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1
Hamad, Asal Mahmud, e Mahmood Gazey Jassam. "A Comparative Study for the Effect of Some Petroleum Products on the Engineering Properties of Gypseous Soils". Tikrit Journal of Engineering Sciences 29, n. 3 (15 ottobre 2022): 69. http://dx.doi.org/10.25130/tjes.29.3.7.
Testo completoAbstract (sommario):
Gypseous soils are considered problematic soils because the soil cavities happen during receiving the water or this type of soil and solving gypsum materials and contract in a soil volume. In this study, three types of gypseous soils are used; soil1, soil2, and soil3 with gypsum content (28.71%, 43.6%, and 54.88%) respectively, petroleum products (engine oil, fuel oil, and kerosene) are added to the soils with percentages (3%, 6%, 9%, and 12%) for each product. The result showed that specific gravity, liquid limit, optimum moisture content (O.M.C), and maximum dry density decreased with an increased percentage of product for all types of products. The direct shear (dry and soaked case) results show that increasing the (angle of internal friction and the soil cohesion) for soil1, soil2, and soil3 by adding engine oil and fuel oil. Still, when the soils were treated with kerosene, the angle of internal friction increased while cohesion decreased. The collapse potential for the treated soils increases with increasing gypsum content for all petroleum products. The collapse potential (CP) for (soil1) decreased by 47% when using 6% of the engine oil, 48.8% when using 9% of the fuel oil, and 55% when using 9% of the kerosene. The same percentage of the petroleum products (engine oil, fuel oil, and kerosene) decrease the collapse potential for (soil2), (47%, 46%, and 50%) respectively and decrease the collapse potential for (soil 3), (51%, 47.7%, and 52%) respectively. In the unconfined compressive test applied on (soil1) using maximum density, the results show that the soil strength increased (26% and 10%) when using 6% and engine oil and fuel oil, respectively, while the soil strength decreased by 29% when treated with 9% of kerosene.
2
Sinegani, A. A. S., e A. Mahohi. "Soil water potential effects on the cellulase activities of soil treated with sewage sludge". Plant, Soil and Environment 56, No. 7 (14 luglio 2010): 333–39. http://dx.doi.org/10.17221/256/2009-pse.
Testo completoAbstract (sommario):
To better understand how water stress and availability affect the enzyme activity and microbial communities in soil, we measured the changes of organic carbon (OC), bacteria and fungi populations, and endoglucanase and exoglucanase activities in a semiarid soil treated with air-dried primary sewage sludge at a rate of 20 g/kg. The water potentials established for soil incubation were: saturation (SA, 0 bar), field capacity (FC, –0.3 bar), and permanent wilting point (PWP, –15 bar). An irrigation treatment was a drying-rewetting cycle (DWC) between –0.3 to –15 bars. After 0, 20, 60 and 90 days of incubation soils were sampled for analysis. The addition of sewage sludge increased soil OC, endoglucanase and exoglucanase activities significantly. The effects of soil moisture, incubation time and their interactions on OC, and endoglucanase and exoglucanase activities in soil were significant. During 20 days of incubation, OC, endoglucanase and exoglucanase activities decreased significantly. Soils incubated in DWC and FC compared to soils incubated in SA and PWP had lower OC contents due to organic matter mineralization. Organic C, exoglucanase and endoglucanase activities significantly increased with increasing soil water potential. The activities of exoglucanase and endoglucanase in soils incubated in SA were significantly higher than those in soils incubated in PWP.
3
Akrivos, J., D. Mamais, K. Katsara e A. Andreadakis. "Agricultural utilisation of lime treated sewage sludge". Water Science and Technology 42, n. 9 (1 novembre 2000): 203–10. http://dx.doi.org/10.2166/wst.2000.0207.
Testo completoAbstract (sommario):
Over one growing season, lime treated dewatered sludge was applied to pot and field cotton cultivation at rates of 0, 10, 20 and 30 t/ha to determine the effects of sludge agricultural reuse on physical and chemical soil properties, on soil and plant heavy metal content and on plant production. In most cases total N and total and soluble P content of the soil increased with addition of sludge. Maximum pH increase caused by addition of lime treated sludge to alkaline soils did not exceed 0.2. Heavy metal content in all plant tissues and soil samples did not increase significantly as a result of sludge amendment. Plant yields increased significantly with sludge addition for the three alkaline soils used in this study. A low plant productivity observed with one of the soil types studied, was attributed to the high concentration of Ni in the soil and the low nutrient content of the soil.
4
Makino, M., T. Takeyama e M. Kitazume. "The influence of soil disturbance on material properties and micro-structure of cement-treated soil". Lowland Technology International 17, n. 3 (2015): 139–46. http://dx.doi.org/10.14247/lti.17.3_139.
Testo completo
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Watabe, Yoichi, Takashi Kaneko e Yu Watanabe. "Cement mix proportion for treated soils recycled from a cement treated soil". Japanese Geotechnical Society Special Publication 4, n. 7 (2016): 168–72. http://dx.doi.org/10.3208/jgssp.v04.j16.
Testo completo
6
Aldaood, Abdulrahman, Amina Khalil, Ibrahim Alkiki e Madyan Alsaffar. "Volume Change and Cracks Behavior of Lime Treated Expansive Soils". Academic Journal of Nawroz University 7, n. 4 (21 dicembre 2018): 81. http://dx.doi.org/10.25007/ajnu.v7n4a274.
Testo completoAbstract (sommario):
This research work study the influence of cyclic wetting and drying on free swell potential of untreated and lime treated expansive clayey soils. Such a study is required to understand the behavior of these soils during wet-dry cycles. Two expansive soils (a polwhite bentonite and a kaolinite) with different plasticity indexes were used in this study. The soil samples were treated with different lime content in the order of (3, 5 and 7% by the dry weight of soil). The lime treated soil samples were cured at 20ºC for 28 and 180 days. The untreated and lime treated soil samples were subjected to four wet-dry cycles. Free swell potential and cracks propagation were studied during lime addition and wet-dry cycles. Results showed that, the free swell potential of untreated soil samples; in general; decreased with increasing wet-dry cycles, and all of the soil samples reached equilibrium after the second cycle. While the cracks propagation increased with these cycles, especially of bentonite soil samples. Larger cracks propagation has been observed in the bentonite soil samples. Lime addition enhanced the free swell potential values of the two expansive soils and there was a drastic decrease in free swelling potential and cracks propagation of these soils. The beneficial effect of lime treatment to control the swelling values was partly lost by the first wet–dry cycles, and the free swell potential increased at the subsequent cycles.
7
Ou, Ou, Xin Gui Zhang e Nian Ping Yi. "The Experimental Study on Strength of Subgrade Soil Treated with Liquid Stabilizer". Advanced Materials Research 194-196 (febbraio 2011): 985–88. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.985.
Testo completoAbstract (sommario):
The liquid soil stabilizer technology is a chemically modified method that can stabilize or reinforce those soils with weak engineering properties. In this paper, two typical high liquid limit soils ，which can not be directly used as subgrade materials，were treated with a new soil stabilizer and it were processed that serials of comparison test on the main engineer properties of soil that pre-and post-treated with soil stabilizer. Then the results show that the soil liquid stabilizer is effective to improve strength and moisture susceptibility for two selected soils. The liquid soil stabilizer technology opened up a new approach for soil improvement and ground treatment.
8
Ali, Nizakat, Aneel Kumar e Manoj Kumar. "Compaction and consolidation characteristics of chemically treated expansive soil of Jamshoro". Mehran University Research Journal of Engineering and Technology 41, n. 2 (1 aprile 2022): 2–11. http://dx.doi.org/10.22581/muet1982.2202.01.
Testo completoAbstract (sommario):
The Jamshoro soil is a weak and expansive soil. The construction of infrastructure on such soils has resulted severe damages and huge maintenance costs. Thus, it needs treatment to enhance its geotechnical properties. This research work investigates the effects of chemical stabilizers such as lime, fly ash, and silica fume on the compaction and consolidation characteristics of expansive soil of Jamshoro. The stabilizers were added individually in different proportions (5%, 10%, 15%, and 20%) in the soil. The results show that maximum dry density decreased, while optimum moisture content increased with the increase of the stabilizers’ content in the soil. The compression index and swelling index of lime treated soil significantly decreased than that of soils treated with silica fume and fly ash. On the other side, the coefficient of consolidation and permeability of fly ash treated soil considerably increased than that of soils treated with silica fume and lime.
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Kurt Albayrak, Zeynep Nese, e Banu Altun. "Strength properties of biopolymer treated clay/marble powder mixtures". Challenge Journal of Concrete Research Letters 12, n. 4 (16 dicembre 2021): 131. http://dx.doi.org/10.20528/cjcrl.2021.04.003.
Testo completoAbstract (sommario):
Depending on their unique layer structures and chemical structures, soil problems such as swelling, settlement and loss of strength can be seen especially on clay soils when exposed to water. Settlement occurring on clay soils on which the structure is built, causes various damages in the building. Additionally, in the clay soil interacting with water, strength loss occurs due to the effect of the building load. Today, when soil improvement techniques are developed and diversified, clay soils can be stabilized by using different additives. A clay soil that has been improved by adding waste marble powder within the scope of this study in certain percentages (5%, 15%, 25%), biopolymer added clay / marble powder samples were obtained by interacting with locust bean gum in certain percentages (0.5%, 1%, 1.5%). There are many studies in the literature on improving clay soils using only marble powder or only biopolymer. In this study, marble powder and biopolymer were used together and thus, the feasibility of a more effective soil improvement has been investigated. The results showed that the unconfined compressive strength of the biopolymer added clay-marble powder mixtures are higher when compared with natural clay. Similarly, shear box test results showed that the unconsolidated-undrained cohesions and internal friction angles of the doped clay samples increased. It was observed that the strength values of marble powder-added clay increased after improving with biopolymer.
10
Sivapullaiah, P. V., A. Sridharan e H. N. Ramesh. "Strength behaviour of lime-treated soils in the presence of sulphate". Canadian Geotechnical Journal 37, n. 6 (1 dicembre 2000): 1358–67. http://dx.doi.org/10.1139/t00-052.
Testo completoAbstract (sommario):
Lime has been used extensively to improve the shear strength of fine-grained soils. It has been recently reported that the presence of sulphate causes abnormal volume changes in lime-stabilized soil. The paper presents the strength behaviour of lime-treated montmorillonitic natural black cotton soil in the presence of varying sulphate contents after curing for periods of up to 365 days. Alteration of soillime reactions in the presence of sulphate affects the strength development by cementation. Consequently, the stressstrain behaviour effective stress paths of soil cured with sulphate are similar to those of normally consolidated soil rather than cemented soils. The reduction in shear strength due to a reduction in effective cohesion intercept occurs for lime-treated soil cured with sulphate for long periods.Key words: clays, cohesion, fabric, friction, shear strength.
11
Alghamdi, Abdulaziz G. "MOBILITY AND DISTRIBUTION OF LEAD IN SOILS TREATED WITH MUNICIPAL SOLID WASTE ASH". Pakistan Journal of Agricultural Sciences 56, n. 02 (1 gennaio 2019): 275–82. http://dx.doi.org/10.21162/pakjas/19.7538.
Testo completoAbstract (sommario):
Lead (Pb) is an inorganic conservative pollutant poses a risk to soils and water resources. Quantifying the potential hazard impacts of Pb in soils needs further circumstances about its mobility and retention as well. The objective of this study was to evaluate the effects of municipal solid waste ash (MSWA) on mobility and distribution of Pb in two types of soil textures. The extent of Pb mobilization in soils amended with different application rates of MSWA has been quantified by soil columns experiment under steady state conditions. Transport of Pb was studied in soil columns by applying Pb solution of 150 mg/L at the rate of 0.09 cm/min for loamy sand soil and 0.035 cm/min for sandy loam soil. The mathematical model- HYDRUS-2D was used to describe this transport. The results indicated that Pb concentrations were extremely low in the leaching solutions collected from soil columns over time regardless of the application rates of MSWA. Application of MSWA increased the recovery of Pb in both soils achieving superiority in loamy sand soil. The Pb distributed in the soil columns ranged between soil leaching solutions and sorbed phase, of which the greater portion was in the sorbed phase. Lead move slowly through soils columns and the distance of movement was about 5 cm to the soil surface and then the concentrations decreased down the soil columns and later disappeared beyond a depth of to 7 cm. Mass balance calculations of Pb according to the HYDRUS-2D mathematical model resulted in values that were similar to those of the experimental data (error ≤ 5%). A soil quality indicator is considered as a key element of sustainable agriculture and hence soil quality plays an important role in deciding the MSWA methods.
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Motasim, Ahmmed Md, Abd Wahid Samsuri, Arina Shairah Abdul Sukor e Amin Mohd Adibah. "Gaseous Nitrogen Losses from Tropical Soils with Liquid or Granular Urea Fertilizer Application". Sustainability 13, n. 6 (12 marzo 2021): 3128. http://dx.doi.org/10.3390/su13063128.
Testo completoAbstract (sommario):
Gaseous loss of N leads to lower nitrogen use efficiency (NUE) of applied urea and N content of the soil. This laboratory study was conducted to compare the nitrogen losses from two tropical soil series (Bungor sandy clay loam and Selangor clay) incubated with either liquid urea (LU) or granular urea (GU) at 0, 300, 400, or 500 mg/kg of soil for thirty days. The NH3 volatilization, N2O emission, and N content in the soils were measured throughout the incubation period. For the same application rate, the total NH3 volatilization loss was higher in GU-treated soils than the LU-treated soils. NH3 volatilization loss continued up to the 15th day in the Selangor soil, while in the Bungor soil series it continued up to the 26th day. Higher amounts of N2O emissions were recorded in GU-treated soils than the LU-treated soils, and N2O emission increased with increasing rate of GU and LU applications in both soils. The N2O emission was higher only in the first few days and then tapered off at the seventh and eighth day in Bungor and Selangor soil series, respectively. The total N2O emission was higher in the Selangor soil series than that of Bungor soil series. The total N content that remained in the LU-treated soils after 30 days of incubation was higher than the GU-treated soils. The total N loss from applied urea was higher in the sandy clay loam Bungor soils than that of clayey Selangor soil series. The results suggest that the LU may be a better N fertilizer source than GU due to lower N loss from NH3 volatilization and N2O emission.
13
Kaveney, Brooke, Jason Condon, Gregory Doran, Francesca Galea e Jessica Rigg. "Soil moisture impacts nitrification from nitrogen fertilisers treated with 3,4-dimethylpyrazole phosphate in acidic soils". Soil Research 60, n. 1 (2022): 86. http://dx.doi.org/10.1071/sr20264.
Testo completoAbstract (sommario):
ContextSuccess of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) is dependent on a range of soil factors including pH and soil organic carbon (OC) content.AimsThis study identified the effect of soil properties and moisture content at the time of DMPP application on the efficiency of DMPP and soil mineral N concentrations.MethodsSoil was collected from paired paddocks with contrasting management, cropping or pasture across three sites. Soil samples were pre-incubated for 7days with moist (−85kPa) or air dried soil to simulate sowing into soil with moisture equivalents of post seasonal break or dry sowing. Urea ammonium nitrate (UAN) was applied with and without DMPP to all soils.Key resultsDMPP inhibited nitrification in all soils, although decreased inhibitory effectiveness was observed in acidic soils compared to neutral soils. Inhibition efficacy on acidic soils was improved when DMPP was applied to dry rather than wet soils. Neutral soils did not observe the same soil moisture effect having similar inhibition efficiency of DMPP observed between dry and wet soil application. Nitrogen fertilisers applied to dry soils nitrified at a greater rate than when applied to wet soils. DMPP decreased the ammonia oxidising bacteria (AOB) population while the ammonia oxidising archaea (AOA) amoA gene copy numbers were unaffected.ConclusionsThis study shows that the lower soil pH and high OC contents can reduce the efficacy of DMPP.ImplicationsWhen using DMPP in Australian broad acre agriculture, knowledge of soil properties including soil pH will determine if application of DMPP is suitable for use before or after a seasonal break rainfall event.
14
Khan, KT, MTA Chowdhury e SM Imamul Huq. "Application of biochar and fate of soil nutrients". Bangladesh Journal of Scientific Research 27, n. 1 (4 gennaio 2016): 11–25. http://dx.doi.org/10.3329/bjsr.v27i1.26221.
Testo completoAbstract (sommario):
An in vitro incubation study was conducted with soil having seven applications of different treatments of biomass and biochar including a control. The biochar and biomass were applied at a rate of 5 t/h a and incubated at field moisture condition for 30, 60 and 90 days individually in different pots. Total organic carbon (C), total nitrogen, phytoavailable nitrogen (N), phosphorus (P), sulfur (S) and potassium (K) were determined at the end of each incubation period. Total soil organic carbon (SOC), showed a substantial declining trend in all the soils - more prominent in the biochar treated soils than its corresponding biomass treated soils. The pH, total N, phytoavailable N, P, K were substantially higher in the biochar treated soils irrespective of the incubation days compared to the biomass treated soils. Conversely, the available S contents of the biochar treated soils were lower than that of biomass treated soils. The effect of biochar on these nutrients vis-à-vis soil health is discussed.Bangladesh J. Sci. Res. 27(1): 11-25, June-2014
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Giridhar, V., e S. Jyothirmayee. "An structured teaching program on Geo-technical application and soil treated". Scientific Journal of India 1, n. 1 (16 novembre 2016): 10–12. http://dx.doi.org/10.21276/24565644/2016.v1.i1.6.
Testo completo
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Puppala, Anand J., Louay N. Mohammad e Aaron Allen. "Engineering Behavior of Lime-Treated Louisiana Subgrade Soil". Transportation Research Record: Journal of the Transportation Research Board 1546, n. 1 (gennaio 1996): 24–31. http://dx.doi.org/10.1177/0361198196154600103.
Testo completoAbstract (sommario):
Lime stabilization is often used to treat subgrade soils when they are soft and cohesive in nature. A study was conducted to investigate the engineering behavior, including the resilient and strength behaviors, of a lime-treated subgrade soil. The lime treatment procedure was adapted from the specifications of the Louisiana Department of Transportation and Development. Silty clay, a soil often found in Louisiana subgrades, is used as a base soil. A summary of various engineering properties of a lime-treated soil from resilient modulus, unconfined compression strength, and California bearing ratio (CBR) tests conducted at five moisture content and dry density levels is provided. Tests were also performed on the raw soil without lime treatment, and these results were compared with those of tests with the lime-treated soil. The comparisons indicate that the present lime treatment method results in an increase in strength and resilient modulus properties and a decrease in plasticity characteristics and plastic strains. A regression model with three constants was used to analyze the resilient modulus test results. The model constants are presented as functions of soil properties. Resilient modulus correlations that use either CBR or unconfined compression strength, moisture content, dry density, degree of compaction, and stresses as dependent attributes are developed.
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Vincent, Azunna Chukwuma, e Chiedozie F. Ikebude. "A Comparative Study on the Stabilization of Soft Soil Using Agricultural Wastes (Baggase Ash (BA) And Rice Husk Ash (RHA)". International Journal of Civil Engineering, Construction and Estate Management 11, n. 2 (15 febbraio 2023): 39–69. http://dx.doi.org/10.37745/ijcecem.14/vol11n23969.
Testo completoAbstract (sommario):
Soft soils are expansive soils, also referred to as tropical clay. Soft soil may cause instability to foundations thereby reducing their service life, this necessitates the adoption of a suitable soil stabilization method in order to improve the engineering properties of soft soils. This research work aims at comparing the strength properties of soft soil stabilized using two different agricultural wastes- Bagasse Ash (BA) and Rice Husk Ash (RHA). The studies were conducted to determine the properties of the natural and treated soft soils, the oxide composition of BA and RHA and the evaluation of the effect of BA and RHA (0, 2, 4, 6, 8, 10 and 12 % by dry weight of the soil) on the index and strength properties of soft soil, the determination of strength characteristics (proctor compaction , unconfined compressive strength (UCS), and California bearing ratio, (CBR) under soaked and unsoaked conditions) of soft soil with BA and RHA mixtures, the optimum blend of both BA and RHA needed for the stabilization of clay soil, the comparison of BA and RHA as stabilizing agents on the performance of clay soil. From the test results, it was observed of the natural moisture content of the clay soil was to be 18.02%, indicating that the soil material is a relatively high water holding material with very low porosity and specific gravities of 2.66. The maximum dry density (MDD) of BA treated soil increased with higher BA content to an optimum BA content lying between 8-10% of dry clay soil and MDD of RHA treated soil continuously decreased with addition of RHA to the clay soil. OMC of BA and RHA treated soils continuously increase, the BA treated clay soil increase with increase in BA content with a possible percentage increment of 11.20% and RHA treated clay soil increases continuously with addition of RHA to a percentage increment of 16.2%. BA content leads to a consequent increase in CBR to an optimum value of 9%. The optimum value of RHA content was obtained as 10% with a maximum CBR value of 28.72%. BA treated clay soil increase both CBR and UCS to percentage increment change of 630% and 91.41% respectively while percentage increments of 619.8% and 85.23% were recorded for RHA treated clay soil. BA thus improved the strength properties better in comparison to RHA although in smaller optimum percentage addition.
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Lu, Jiayu, Hui Wang e Chuanwang Hu. "Changes in Physicochemical Properties of Typical Subtropical Soils under Different Treated Domestic Wastewater Irrigation Modes". Sustainability 14, n. 16 (17 agosto 2022): 10197. http://dx.doi.org/10.3390/su141610197.
Testo completoAbstract (sommario):
Irrigation with treated domestic wastewater (TWW) affects the physicochemical properties of soils, but little research has been conducted for different soils in subtropical regions. Consequently, in order to evaluate the effects of domestic wastewater (treated by A2/O process) irrigation on the hydraulic properties, soil salinity and sodicity of four typical subtropical agricultural soils, a soil-column experiment was conducted for one year with eight cycles of wetting and drying. A clay soil (red soil), a silty clay soil (aquic soil), a loamy clay soil (purple soil), and a silty clay loam soil (paddy soil) were subjected to three irrigation modes: (a) cyclic irrigation with TWW (W1), (b) alternating irrigations with TWW and distilled water (W2), and (c) irrigation with distilled water as a control (CK). Our results indicated that EC values increased significantly (p < 0.05) with TWW irrigation for all the soils. TWW irrigation increased the concentrations of Na+, K+, Ca2+, Mg2+, and SAR, ESP values in the red soil, for the W2 treatment especially. In contrast, it decreased Na+, K+, Ca2+, Mg2+ accumulation and ESP values in the aquic soil. Moreover, the soil physical properties exhibited correlations with soil salinity. The saturated hydraulic conductivity (Ks) of the red soil, purple soil, and paddy soil were lower under the W1 and W2 treatments than CK, but the Ks of the aquic soil for W1 were 183.7% higher than that under CK. The unsaturated hydraulic conductivity (Kψ) of the purple soil and paddy soil decreased after TWW irrigation, but those of the aquic soil increased. The water-retention capacities (WRCs) of the TWW-irrigated red soil and aquic soil decreased as a consequence of a shift in the pore-size distribution toward wider pores, but the those of the purple soil and paddy soil improved, associated with narrower pores. The W2 treatment alleviated the impact of TWW on the aquic soil, purple soil, and paddy soil but negatively affected the physical properties, salinity, and sodicity of the red soil. Our results will provide useful information for managing soil and water under TWW irrigation in subtropical regions.
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Zuo, Wengang, Yuxi Zhou, Yutian Yao, Chao Chen, Fan Wang, Hao Peng, Tianyang Qin et al. "Influences of Exogenic Organic Materials Application on Soil Fertility Status and Paddy Growth under a Coastal Saline Soil Condition". Agronomy 13, n. 9 (29 agosto 2023): 2280. http://dx.doi.org/10.3390/agronomy13092280.
Testo completoAbstract (sommario):
Paddy cultivation in saline soil can rapidly reduce soil salinity, which is an important approach for managing, utilizing, and improving such soils. However, the high salinity of saline soil severely limits the sustainability of paddy production. Adding exogenic organic material to improve soil fertility in saline soil is a key measure for obtaining high-yield, efficient and sustainable cultivation of paddy. This study used a field experiment to explore the influences of different organic materials application on soil desalination and fertility improvement in saline paddy soil. The results showed that the application of dairy manure (DM), sludge vermicompost (SV), and vinegar residue (VR) reduced soil barrier factors, including electrical conductivity (EC) and pH, increased soil fertility, including soil organic carbon (SOC), nitrogen (N), and phosphorus (P), and promoted paddy growth in saline soil. Specifically, soil EC decreased by 29.0%, 32.9% and 49.4% and paddy biomass increased by 27.7%, 63.7% and 107.6% in DM, SV, and VR-treated soils with the highest application rates, respectively, compared to the control. At an equal carbon application rate, VR was more conducive to decreasing soil EC and pH and increasing paddy biomass. Compared to DM and SV, VR addition resulted in an average decrease of 20.7% and 19.1% in soil EC, respectively, and an average increase of 57.3% and 29.5% in paddy biomass. In addition, soil water-stable aggregates (WSA), SOC, N, and P contents in VR-treated soil were lower than those in DM and SV-treated soils. Correlation and path analysis revealed that there was a significant negative correlation between paddy biomass and soil barrier factors. However, EC in VR-treated soil had a direct negative effect on paddy biomass, while EC in DM and SV-treated soils had an indirect negative effect on paddy biomass. Additionally, the direct contribution of soil pH to paddy biomass was higher with VR (−1.49) than that with DM (−0.21) and SV (0.89). In contrast to DM and SV, the effect of soil WSA on paddy biomass in VR-treated soil was mainly an indirect positive effect, and the direct effect was negative. The corresponding results provided new options and ideas for the efficient utilization of saline soils and high-yield cultivation of paddy.
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Awn, Safa Hussain Abid, e Jasim M. Abbas. "Improvement of Soft Soil by Stone Column Treated with Bentonite". Key Engineering Materials 857 (agosto 2020): 283–91. http://dx.doi.org/10.4028/www.scientific.net/kem.857.283.
Testo completoAbstract (sommario):
Soft clayey soils cover wide Iraqi areas specially the regions close to rivers and the southern part of this country Heavy weight structures like: highways, dams, multiple story buildings are suffering unacceptable settlement, when constructing on soft soils. The high contamination of water in such soils decrease the effective stress and reduce bearing capacity. The need was appeared to improve such problematic soil by the use of new technique of stone column treated with different percentages of natural bentonite by a series of field tests using full scale concrete footing constructed on soft soil in addition to a laboratory model to investigate settlement with time at constant stress. The soil that used in this study is natural clayey soil, brought from a location south of Diyala governorate, from a farm area. The study includes also: The effect of stone column diameter treated with bentonite on the behavior of footing constructing on soft clayey soil, The effect of stone column length on the behavior of footing on such soils. Results of field and laboratory model tests reviled that the treated model by stone column mixed with 40% bentonite is the ideal one, which reduces the settlement by 55%. In other hand problems of uneven settlements appear when using 60% bentonite as a mix proportion. The Ideal slenderness ratio (Ds/Ls<25%). The effective depth of stone column treated with bentonite is (1/3H).
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Hussein, Ahmed H., Farouk M. Muhauwiss e Riyadh A. Abdul-Jabbar. "Collapsibility of Gypseous Soil Treated with Pectin-Biopolymer through Leaching". Journal of Engineering 2023 (4 marzo 2023): 1–11. http://dx.doi.org/10.1155/2023/6379835.
Testo completoAbstract (sommario):
Gypsum reinforcement in dry soil provides activity resistance. It quickly becomes a source of danger in the conditions of partial and complete soaking of gypsum soil as a result of the dissolution of gypsum, which poses a great danger to the structures built on this soil. The danger increases when water flows through it and works to leach the soil, which leads to the loss of its mass by leaching gypsum. The soil is chemically and mechanically improved to enhance its geotechnical properties, but despite its great advantages in strengthening, it has significant negative effects on the ecosystem, so the use of environmentally friendly materials is essential. Pectin was selected as an improved biopolymer and added at three different contents (0.5, 1, and 2)% to create a soil mixture and at four different gypsum contents (10, 20, 40, and 62%) to evaluate the chemical and mechanical properties of the improved mixture. Develop an engineering model to leach the soil and pectin mixture. The results showed a significant decrease in CH and CP. values due to biogel encapsulation of soil particles and pore filling properties. The percentage decrease in the values of (CH) reaches (0.67, 73, 75, and 68%) for soils 1, 2, 3, and 4, respectively. After soil (1, 2, 3, and 4), CP values decreased in percent (0.63, 0.63, 0.65, and 0.7%). TDS decreased at a biopolymer content of 2% from 1050, 1200, 2200, and 2500 mg/ml to 320, 540, 468, and 570 mg/ml of soils 1, 2, 3, and 4, respectively.
22
Quang, Nguyen Duy, e Jin Chun Chai. "Permeability of lime- and cement-treated clayey soils". Canadian Geotechnical Journal 52, n. 9 (settembre 2015): 1221–27. http://dx.doi.org/10.1139/cgj-2014-0134.
Testo completoAbstract (sommario):
The permeability (k) of lime- and cement-treated clayey soils was investigated in the laboratory by flexible-wall permeability tests and oedometer tests. Test results indicate that for the cement-treated soils (with up to 8% cement content by dry weight), the value of k is almost equal to that of untreated soils under identical void ratio (e) conditions, and the k value decreases significantly when the cement content is higher than 8%. For lime-treated soils, the threshold lime content is about 4%. Investigation of the soil microstructure using the mercury intrusion porosimetry (MIP) test and scanning electron microscope (SEM) imaging indicates that when the cementation products formed by the pozzolanic reaction fill mainly the intra-aggregate pores, the value of k is comparable for the treated and untreated samples. When the cementation products begin to fill the interaggregate pores, the value of k of the treated sample becomes smaller than that of the untreated soil sample under the identical e value condition. An indication that the cementation products have filled the interaggregate pores is the rapid increase in strength of the treated soil.
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Aldaood, Abdulrahman, Marwen Bouasker e Muzahim Al-Mukhtar. "Soil–water characteristic curve of lime treated gypseous soil". Applied Clay Science 102 (dicembre 2014): 128–38. http://dx.doi.org/10.1016/j.clay.2014.09.024.
Testo completo
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Baharuddin, INZ, Hairin Taha, RC Omar, R. Roslan, FS Buslima e K. Rizal. "Evaluation of Vege-Grout Treated Slope by Electrical Resistivity". International Journal of Engineering & Technology 7, n. 4.35 (30 novembre 2018): 168. http://dx.doi.org/10.14419/ijet.v7i4.35.22352.
Testo completoAbstract (sommario):
Soil stabilization using bio-grouting method based on microbial induced calcium carbonate precipitation (MICP) technology has been developed recently to improve the engineering properties of the soil. This new technology could provide an alternative to traditional methods of soil stabilization using soil-cement and chemical grouting. Vegetable waste is a good source for the growth of various kinds of microorganisms which is suitable to be applied as bio-grouting material. The bio-grout extract known as vege-grout was able to induce bio-cementation and bio-clogging process. In this study, vege-grout from vegetable waste was injected into the soil to strengthen the slope and improve the mechanical properties of the affected area. The changes in the subsurface soil after treatment with vege-grout were evaluated by electrical resistivity measurement. Resistivity test showed the resistance in the soil has increased after the grouting using vege-grout. Results indicated that the underneath soils have transformed from medium dense sand to dense sand. The water containment in the subsurface appeared to shift deeper into the ground. SEM analysis showed evidence of bio-clogging process as a result of microbial activities in the soil. This analysis showed that the vege-grout from vegetable waste has successfully strengthened and stabilized the slope from soil erosion.
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Saad, Ahmed Hassan, Haslinda Nahazanan, Zainuddin Bin Md Yusoff, Muskhazli Mustafa, Mohamed Hamdy Elseknidy e Angham Ali Mohammed. "Evaluating Biosedimentation for Strength Improvement in Acidic Soil". Applied Sciences 11, n. 22 (16 novembre 2021): 10817. http://dx.doi.org/10.3390/app112210817.
Testo completoAbstract (sommario):
Marine clay soils are problematic soils in the construction industry when they are subjected to construction loads. When these soils are loaded, they lose their structure. This leads to the soil being unable to withstand loads of any magnitude without exhibiting significant, permanent deformations. In order to stabilize the marine soil, new methods for soil improvement were built upon biogrouting by incorporating physical, biological and chemical treatments into the soil. However, the biggest challenge of this method is the bacteria migration through the soil medium. To overcome this issue, the electrokinetic phenomenon can be utilized alongside biogrouting to prevent the bacteria migration. In this regard, the present study applied electrobiogrouting stabilization to investigate the improvement of acidic marine clay soil with a pH of 3.69. To accomplish this, two large-scale physical models with dimensions of 500 × 300 × 1200 mm were fabricated to examine the influence of two different treated distances between the inlet and outlet—450 mm (D45) and 600 mm (D60)—on the stability of the treated soil. It was observed that the shear strength of the treated soil improved significantly. The shear strength at the D45 treated distance increased from 3.65 kPa (untreated soil) to 28.14 kPa (treated soil). However, the strength increased by increasing the treated distance. In addition, compressibility and soil electrical conductivity were reduced significantly, and the Atterberg limits were significantly enhanced from OH to OL. The reasons for the enhancement of treated soil were the formation of CaCO3, which filled the soil voids, and that the water content was reduced. To address issues with marine clay soil, this study aims to minimize the high cost of a special foundation system and the use of non-environmentally friendly materials such as calcium-based binders, aside from the reduction of deformations caused by loading. The findings of this study can be used for acidic soils and the improvement of soil’s geotechnical behavior in general.
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Zhong, Yuqing, Guanghua Cai, Shiquan Wang, Huajin Qin, Caihong Zhang e Jiangshan Li. "Influence of Organic Content on the Mechanical Properties of Organic-Rich Soils Stabilized with CaO-GGBS Binder and PC". Water 14, n. 19 (28 settembre 2022): 3053. http://dx.doi.org/10.3390/w14193053.
Testo completoAbstract (sommario):
Organic-rich soil is a typical special soil often encountered in foundation treatment. Previous research has revealed that Portland cement (PC) not only pollutes the environment but is significantly affected by organic matter during its hydration and cementation. Although quicklime (CaO)-GGBS binder (CG) is an effective alternative to PC, its efficiency in treating organic-rich soils has not been studied. In this study, organic-rich soil was treated with two binders of CG and PC. The physical, mechanical, and chemical characteristics of the stabilized soils were tested at various organic contents, binder contents, and curing ages. The results show that the cracks in two treated soils increase with the increase in organic content and the reduction in binder content. CG-treated soils are more likely to shed big lumps after damage than PC-treated soils. The unconfined compressive strength (qu) and deformation modulus (E50) of stabilized soils increase with the increasing curing age and binder content but the decreasing organic content. The E50 of PC-treated soil is about 22~73 times qu, and the E50 of CG-treated soil shows an excellent linear relationship with qu. The moisture content of two treated soils increases as the organic content grows, but it falls as the curing age and binder content increase. The soil pH rises with the increasing organic content and binder content, but it declines with increased curing age. The strength development of organic-rich soils treated by the CG binder has an evident attenuation with the organic content. Given its possible environmental benefit, alkali (especially low calcium)-activated binder is appropriate for practical engineering with modest strength needs.
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Little, Dallas N., Bruce Herbert e Sachin N. Kunagalli. "Ettringite Formation in Lime-Treated Soils". Transportation Research Record: Journal of the Transportation Research Board 1936, n. 1 (gennaio 2005): 51–59. http://dx.doi.org/10.1177/0361198105193600107.
Testo completoAbstract (sommario):
The use of calcium-based stabilizers such as calcium oxide (lime) in sulfate-bearing clay soils has historically led to structural distress because of the formation of a mineral called ettringite and possibly thaumasite. In trying to control the damage associated with such formations, engineers have attempted to determine a threshold level of soluble sulfates–-a quantity that is relatively easy and quick to measure at which significant ettringite growth and, therefore, structural distress occurs. This is indeed a complex problem related to not only soil composition but also construction methods, availability of water, ion migration, and the ability of the void structure to accommodate the expansive mineral growth. Unfortunately, experience alone and rules-of-thumb based on experience are not sufficient to deal with this complex issue. Thermodynamic geochemical models of the lime-treated soil can be used as a first step toward establishing thresholds for problematic levels of soluble sulfates for a specific soil. A foundation for the model development is presented, and two soils are compared to illustrate their sensitivities to ettringite growth on the addition of lime. Because the model predicts ettringite growth on the basis of site-specific properties, the model can be used to assess the potential amelioration effects of soluble silica.
28
Khiari, Lotfi, e Léon E. Parent. "Phosphorus transformations in acid light-textured soils treated with dry swine manure". Canadian Journal of Soil Science 85, n. 1 (1 febbraio 2005): 75–87. http://dx.doi.org/10.4141/s03-049.
Testo completoAbstract (sommario):
Organic matter can sorb P in acid soils through metal-organic matter-phosphate complexes. The pyrophosphate extractable Al and Fe and soil C contents were hypothetized to influence P partitioning in Ferro-Humic Podzols. Reaction of added P may be mitigated by adding lime or organic matter as dry swine manure (DSM) together with mineral P fertilizers. Three soils had 40 to 50 g kg-1 of soil organic matter (SOM) content, and 76 to 140 mmol (Al + Fe)pyro kg-1. A peaty soil phase had 200 g SOM kg-1, and 58 mmol (Al + Fe)pyro kg-1. Rates of monoammonium phosphate were 0, 27, 69, and 144 kg P ha-1 in a simulated fertilizer band. Rates of DSM and lime were 800 and 185–369 mg per 35 mL of soil, respectively. After 6 wk of incubation, soil P was fractionated sequentially into aluminium bound P (Al-P), iron bound P (Fe-P), and loosely bound P. Total P, desorbed P and organic P were determined in separate subsamples. A proportion of 79–92% of added P was recovered as Al-P and Fe-P in the three low SOM soils, compared to 51–61% in the high SOM soil. The DSM increased loosely bound P from 25 to 34% in the high SOM soil and from 4.8 to 5.9% in low SOM soils. With DSM, the proportion of desorbed P was much higher in the high (70%) than in low SOM (22%) soils. Compared to the non-amended treatment, lime showed no significant effect on any P fraction but desorbed P. The DSM increased P availability in the fertilizer band considerably more in the soil having the lowest (Al + Fe)pyro/C ratio. Key words: P fractionation, organic ligand, P sorption, fertilizer band
29
Motasim, Ahmmed Md, Abd Wahid Samsuri, Arina Shairah Abdul Sukor e Amin Mohd Adibah. "Nitrogen Dynamics in Tropical Soils Treated with Liquid and Granular Urea Fertilizers". Agriculture 11, n. 6 (14 giugno 2021): 546. http://dx.doi.org/10.3390/agriculture11060546.
Testo completoAbstract (sommario):
The mineralization of urea fertilizer mostly regulates the nitrogen dynamics in the soil. A laboratory-scale study was conducted to compare the nitrogen dynamics in two tropical soil series incubated with either liquid urea (LU) or granular urea (GU) at 0, 300, 400 or 500 mg/kg of soil. The soils samples used in the experiment were the Bungor and Selangor soil series which have a sandy clay loam and clay texture, respectively. The NH4+-N, NO3−-N concentration in the soils were measured for four weeks to determine the urea-N mineralization while ten pore volumes of water were used for the NH4+-N and NO3−-N leaching loss. At the same application rate, higher NH4+-N and NO3−-N concentrations were recorded in the LU applied soils throughout the incubation period in case of N mineralization. Urea-N recovery was higher in GU than LU treated soils in the first two weeks while no urea-N was present in both GU and LU treated soils after the third week of incubation. The leaching of N (NH4+-N and NO3−-N) was higher in GU treated soils than that of LU and leaching was increased with increased application rate in both LU and GU in both soils. The NH4+-N and NO3−-N concentrations were higher in the Selangor soil whereas the total N leaching loss was higher in Bungor soil. The results suggest that the LU was a better N fertilizer source than GU for rapid mineralization, quicker N availability and lower N leaching loss.
30
Vermes, László, e B. Biró. "Study on the Revitalization Potential of Thermal-treated Soils". Agrokémia és Talajtan 51, n. 1-2 (1 marzo 2002): 129–38. http://dx.doi.org/10.1556/agrokem.51.2002.1-2.16.
Testo completoAbstract (sommario):
A pot experiment was set up at the Experimental Farm of the Faculty of Horticultural Sciences of the Szent István University in 2001 investigating the revitalization effect of selected treatments on thermal-treated soils and other production substances. In the experiment 6 factors and 7 treatments were used, each in 4 replicates, using rape ( Brassica napus DC ) as test plant. During the time period of the experiment (29 May-17 August) continuous observations and measurements were conducted, plant and soil analyses - chemical and microbiological - were made to establish the main effects and results of the different treatments. These are discussed in the paper in detail. Although the soil-vitalization procedures were of great success, no treatment in the experiment had an extremely positive effect. Various additives, however could enhance the re-colonization processes significantly. According to the basic factors (the soils or substrates) the best treatments were: the A1 (clay-pearl) additive and the C2, C3 factors (the medium and low temperature soil treatments). Among the treatment combinations, treatments IV and VII were the best ( compost and compost + inocula addition). This fact shows that the compost in a good quality, and the compost enriched, compost extracted microbial inocula can play the most important role in the revitalization of thermal-treated soils. Manure addition and the manure + inocula treatment can also be used as a prominent treatment in the restoration, to increase the organic matter content and the microbial activity in soils. The single alga- and microbial inocula treatment was not successful permanently, therefore their use - without adding any parallel organic matter - cannot be recommended. Investigations of the soil microbial activity showed that the lowest temperature of thermal treatments had resulted a more effective revitalization. The clay-pearl additive increased the persistency and activity of the microbes in the soil. It was also obviously found that the organic additives with or without the microbial inoculations could be used potentially as the best soil revitalization treatments.
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Fatehi, Hadi, Dominic E. L. Ong, Jimmy Yu e Ilhan Chang. "Biopolymers as Green Binders for Soil Improvement in Geotechnical Applications: A Review". Geosciences 11, n. 7 (15 luglio 2021): 291. http://dx.doi.org/10.3390/geosciences11070291.
Testo completoAbstract (sommario):
Soil improvement using biopolymers has attracted considerable attention in recent years, with the aim to reduce the harmful environmental effects of traditional materials, such as cement. This paper aims to provide a review on the environmental assessment of using biopolymers as binders in soil improvement, biopolymer-treated soil characteristics, as well as the most important factors affecting the behavior of the treated soil. In more detail, environmental benefits and concerns about the use of biopolymers in soil improvement as well as biopolymer–soil interaction are discussed. Various geotechnical properties are evaluated and compared, including the unconfined compressive strength, shear strength, erosion resistance, physical properties, and durability of biopolymer-treated soils. The influential factors and soil and environmental conditions affecting various geotechnical characteristics of biopolymer-treated soils are also discussed. These factors include biopolymer concentration in the biopolymer–soil mixture, moisture condition, temperature, and dehydration time. Potential opportunities for biopolymers in geotechnical engineering and the challenges are also presented.
32
Jalali, Mohsen, Maryam Saeedi Lotf e Faranak Ranjbar. "Changes in some chemical properties of saline-sodic soils over time as affected by organic residues: An incubation study". Polish Journal of Soil Science 53, n. 1 (22 giugno 2020): 1. http://dx.doi.org/10.17951/pjss.2020.53.1.1.
Testo completoAbstract (sommario):
<p>Salinization and sodification of agricultural lands in arid and semi-arid regions of the world are two limiting factors in the crop production. This study was conducted to evaluate the effect of readily available agricultural residues on changing some chemical properties of saline-sodic soils. Wheat, potato, sunflower, and canola residues were separately added into three saline-sodic soils at a rate of 2% by weight and thoroughly mixed with soils. Control and treated soils were incubated for 168 days at a constant moisture and temperature. The pH, electrical conductivity (EC), soluble cations, available nitrate (NO3-) and phosphorous (P), cation exchange capacity (CEC), and exchangeable sodium percentage (ESP) were measured during the incubation. The EC increased in the response to the incorporation of plant residues, whereas the pH was reduced. The application of organic components in soils increased CEC and decreased ESP. The results showed that the maximum reduction in ESP was observed in the potato treatment because of the highest Ca2+ concentration. The average reduction in ESP of treated soil samples at the end of incubation followed this order: 16.1% (potato residue-treated soil) >12.7% (canola residue-treated soil) >11.1% (wheat residue-treated soil) >9.6% (sunflwer residue-treated soil). The potato residue was the most effective amendment in changing the chemical properties of saline-sodic soils in comparison with other organic residues. The results indicated that the application of organic residues had a positive impact on reducing the soil sodicity and improving the soil fertility depending on their chemical composition.</p>
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Tuxhorn, Gary L., Fred W. Roeth, Alex R. Martin e Robert G. Wilson. "Butylate Persistence and Activity in Soils Previously Treated with Thiocarbamates". Weed Science 34, n. 6 (novembre 1986): 961–65. http://dx.doi.org/10.1017/s0043174500068181.
Testo completoAbstract (sommario):
Butylate [S-ethyl bis(2-methylpropyl)carbamothioate] persistence was compared in three soils that were treated annually with four thiocarbamate herbicides in 1981 and 1982. Butylate degraded faster in soils treated two consecutive years with butylate + dichlormid (2,2-dichloro-N,N-di-2-prophenylacetamide) than in soils treated for 2 yr with EPTC (S-ethyl dipropyl carbamothioate) + dichlormid, cycloate (S-ethyl cyclohexylethylcarbamothioate), vernolate (S-propyl dipropylcarbamothioate) + dichlormid, or from previously untreated soils. Butylate + dichlormid applications in 1981 and 1982 enhanced butylate degradation in 1983 at all locations and reduced weed control at two locations. Previously untreated soil or soil previously treated with two annual applications of butylate + dichlormid was treated with 6 ppmw butylate, incubated for 14 days, analyzed for residual butylate, and bioassayed for herbicide activity. Bioassay indicated higher herbicidal activity than was predicted by the residual butylate concentration. A herbicidally active metabolite may be produced during the soil degradation of butylate.
34
Glaspie, Calvin F., Eric A. L. Jones, Donald Penner, John A. Pawlak e Wesley J. Everman. "Effect of Clay, Soil Organic Matter, and Soil pH on Initial and Residual Weed Control with Flumioxazin". Agronomy 11, n. 7 (29 giugno 2021): 1326. http://dx.doi.org/10.3390/agronomy11071326.
Testo completoAbstract (sommario):
Greenhouse studies were conducted to evaluate the effects of soil organic matter content and soil pH on initial and residual weed control with flumioxazin by planting selected weed species in various lab-made and field soils. Initial control was determined by planting weed seeds into various lab-made and field soils treated with flumioxazin (71 g ha−1). Seeds of Echinochloa crus-galli (barnyard grass), Setaria faberi (giant foxtail), Amaranthus retroflexus (redroot pigweed), and Abutilon theophrasti (velvetleaf) were incorporated into the top 1.3 cm of each soil at a density of 100 seeds per pot, respectively. Emerged plants were counted and removed in both treated and non-treated pots two weeks after planting and each following week for six weeks. Flumioxazin control was evaluated by calculating percent emergence of weeds in treated soils compared to the emergence of weeds in non-treated soils. Clay content was not found to affect initial flumioxazin control of any tested weed species. Control of A. theophrasti, E. crus-galli, and S. faberi was reduced as soil organic matter content increased. The control of A. retroflexus was not affected by organic matter. Soil pH below 6 reduced flumioxazin control of A. theophrasti, and S. faberi but did not affect the control of A. retroflexus and E. crus-galli. Flumioxazin residual control was determined by planting selected weed species in various lab-made and field soils 0, 2, 4, 6, and 8 weeks after treatment. Eight weeks after treatment, flumioxazin gave 0% control of A. theophrasti and S. faberi in all soils tested. Control of A. retroflexus and Chenopodium album (common lambsquarters) was 100% for the duration of the experiment, except when soil organic matter content was greater than 3% or the soil pH 7. Eight weeks after treatment, 0% control was only observed for common A. retroflexus and C. album in organic soil (soil organic matter > 80%) or when soil pH was above 7. Control of A. theophrasti and S. faberi decreased as soil organic matter content and soil pH increased. Similar results were observed when comparing lab-made soils to field soils; however, differences in control were observed between lab-made organic matter soils and field organic matter soils. Results indicate that flumioxazin can provide control ranging from 75–100% for two to six weeks on common weed species.
35
Khaskhoussy, K., B. Kahlaoui, B. Messoudi Nefzi, O. Jozdan, A. Dakheel e M. Hachicha. "Effect of Treated Wastewater Irrigation on Heavy Metals Distribution in a Tunisian Soil". Engineering, Technology & Applied Science Research 5, n. 3 (21 giugno 2015): 805–10. http://dx.doi.org/10.48084/etasr.563.
Testo completoAbstract (sommario):
Treated wastewater (TWW) may contain toxic chemical constituents that pose negative environmental and health impacts. In this study, soil samples under treated wastewater irrigation were studied. For this purpose, six plots were made in an irrigated area in north of Tunisia and treated with two water qualities: fresh water (FW) and treated wastewater (TWW). Five soil depths were used: 0-30, 30-60, 60-90, 90-120 and 120-150 cm. The TWW irrigation increased significantly (P≤0.05) the soils’ EC, Na, K, Ca, Mg, Cl, SAR, Cu, Cd and Ni and had no significant (P ≤0.05) effect on the soils’ pH, Zn, Co and Pb contents. EC, Na, Cl, SAR, Zn and Co increased significantly with soil depth. The results for K, Ca, Mg, Cd, Pb and Ni exhibited similar repartition in different layers of soil. It was also shown that the amount of different elements in soil irrigated with fresh water (FW) were less compared with the control soil.
36
Le Runigo, B., O. Cuisinier, Y. J. Cui, V. Ferber e D. Deneele. "Impact of initial state on the fabric and permeability of a lime-treated silt under long-term leaching". Canadian Geotechnical Journal 46, n. 11 (novembre 2009): 1243–57. http://dx.doi.org/10.1139/t09-061.
Testo completoAbstract (sommario):
The long-term performance of lime-treated soil is still in question, especially in the case of the use of such soils to build earthen structures in permanent contact with water (i.e., dams, river levees, etc.) Indeed, water circulation may induce significant alteration of the improvements brought by the lime treatment. In this context, the main objective of this work is to study the long-term behaviour (durability) of lime-treated soils submitted to water circulation as well as to determine the most favourable initial soil compaction in terms of lime-treated soil durability. First, the impact of lime addition on soil microstructure is investigated with mercury intrusion porosimetry tests. This was done to highlight the effect of curing time, lime dosage, and compaction on soil initial permeability, a critical parameter in terms of long-term behaviour of the lime-treated soil. Then, lime-treated soil samples were submitted to an accelerated circulation of water over a period of 150 days. The obtained results show that soil permeability did not fluctuate with circulation time. This has been confirmed by the results obtained on the samples’ microstructure that remained stable throughout the experiments.
37
Vail, Zhu, Tang, Anderson, Moroski e Montalbo-Lomboy. "Desiccation Cracking Behavior of MICP-Treated Bentonite". Geosciences 9, n. 9 (2 settembre 2019): 385. http://dx.doi.org/10.3390/geosciences9090385.
Testo completoAbstract (sommario):
This study aims to characterize the effect of microbial-induced calcite precipitation (MICP) on the desiccation cracking behaviors of compacted calcium bentonite soils. We prepare six groups of samples by mixing bentonites with deionized water, pure bacteria solution, pure cementation solution, and mixed bacteria and cementation solutions at three different percentages. We use an image processing tool to characterize the soil desiccation cracking patterns. Experimental results reveal the influences of fluid type and mixture percentage on the crack evolution and volumetric deformation of bentonite soils. MICP reactions effectively delay the crack initiation and remediate desiccation cracking, as reflected by the decreased geometrical descriptors of the crack pattern such as surface crack ratio. The mixture containing 50% bacteria and 50% cementation solutions maximizes the MICP treatment and works most effectively in lowering the soil cracking potential. This study provides new insights into the desiccation cracking of expansive clayey soils and shows the potential of MICP applications in the crack remediation.
38
Rétháti, Gabriella, Adrienn Vejzer, Barbara Simon, Ramadan Benjared e György Füleky. "Examination of zinc adsorption capacity of soils treated with different pyrolysis products". Acta Universitatis Sapientiae, Agriculture and Environment 6, n. 1 (1 novembre 2014): 33–38. http://dx.doi.org/10.2478/ausae-2014-0010.
Testo completoAbstract (sommario):
Abstract Organic matter input into soils is essential regarding agricultural, environmental and soil science aspects as well. However, the application of the pyrolysed forms of biochars and materials with different organic matter content gained more attention in order to decrease the emission of the green house gases (CO2, N2O) from the soil. During pyrolysis, the materials containing high organic matter (biomass-originated organic matter) are heated in oxygen-free (or limited amount of oxygen) environment. As a result, the solid phase, which remains after eliminating the gases and liquid phase, is more stable compared to the original product, it cannot be mineralized easily in the soil and its utilization is more beneficial in terms of climatic aspects. Furthermore, it can improve soil structure and it can retain soil moisture and cations in the topsoil for long periods of time, which is very important for plants. In our experiment, the effects of biochar and bone char were examined on soils by zinc adsorption experiments. Based on our experiments, we concluded that the pyrolysis products can have significant Zn adsorption capacity compared to the soil. Bone ash can adsorb more Zn than the charcoal product. The Zn adsorption capacity of soils treated by pyrolysis products can be described by Langmuir adsorption isotherms. However, based on the amount of pyrolysis products, one or two term Langmuir isotherm fits well on the experiment data, which depends on the time the pyrolysis product has spent in the soil.
39
Sun, H. Y., S. P. Deng e W. R. Raun. "Bacterial Community Structure and Diversity in a Century-Old Manure-Treated Agroecosystem". Applied and Environmental Microbiology 70, n. 10 (ottobre 2004): 5868–74. http://dx.doi.org/10.1128/aem.70.10.5868-5874.2004.
Testo completoAbstract (sommario):
ABSTRACT Changes in soil microbial community structure and diversity may reflect environmental impact. We examined 16S rRNA gene fingerprints of bacterial communities in six agroecosystems by PCR amplification and denaturing gradient gel electrophoresis (PCR-DGGE) separation. These soils were treated with manure for over a century or different fertilizers for over 70 years. Bacterial community structure and diversity were affected by soil management practices, as evidenced by changes in the PCR-DGGE banding patterns. Bacterial community structure in the manure-treated soil was more closely related to the structure in the untreated soil than that in soils treated with inorganic fertilizers. Lime treatment had little effect on bacterial community structure. Soils treated with P and N-P had bacterial community structures more closely related to each other than to those of soils given other treatments. Among the soils tested, a significantly higher number of bacterial ribotypes and a more even distribution of the bacterial community existed in the manure-treated soil. Of the 99 clones obtained from the soil treated with manure for over a century, two (both Pseudomonas spp.) exhibited 100% similarity to sequences in the GenBank database. Two of the clones were possible chimeras. Based on similarity matching, the remaining 97 clones formed six major clusters. Fifty-six out of 97 were assigned taxonomic units which grouped into five major taxa: α-, β-, and γ-Proteobacteria (36 clones), Acidobacteria (16 clones), Bacteroidetes (2 clones), Nitrospirae (1 clone), and Firmicutes (1 clone). Forty-one clones remained unclassified. Results from this study suggested that bacterial community structure was closely related to agroecosystem management practices conducted for over 70 years.
40
Lavanya, S., e V. Krishna Murthy. "Suitability of Electronic Nose as a Reflective Tool to the Measurement of Soil Fertility Factors". Kathmandu University Journal of Science, Engineering and Technology 13, n. 2 (8 ottobre 2018): 39–47. http://dx.doi.org/10.3126/kuset.v13i2.21282.
Testo completoAbstract (sommario):
Humic Acid (HA) and Fulvic Acid (FA) contribute prominently to soil fertility. They are aromatic in nature and hence can be determined by sensory array. This is apparently the first report on the employment of Electronic nose (E-nose) to detect HA and FA extracted from soil. The aim was to evaluate the E-nose sensor response to HA and FA chemically extracted from different agricultural soils. Humic acid and Fulvic acid were extracted from collected agricultural soils and the aroma was measured by E-nose from each of the seven soils. Their presence was confirmed by fluorescence spectroscopy. The Norm Aroma Index (NAI) was measured for: soil, soil after heat treatment, heat treated soil amended with extracted HA, heat treated soil amended with extracted FA, extracted HA and extracted FA. The NAI values were descending in the order: heat treated soil amended with extracted HA/FA, extracted HA/FA, soil (untreated) and heat treated soil. This indicates that HA and FA are detected by E-nose. It was also observed that the most sensitive sensors were 2, 3, 4, 8 and 5 for all agricultural soils tested. Out of the eight sensors in the sensory array of E-nose, above mentioned sensors consistently exhibited high response and these sensors when customized into a small unit may act as a soil fertility tester.Kathmandu University Journal of Science, Engineering and TechnologyVol. 13, No. 2, 2017, page: 39-47
41
Morugán-Coronado, A., V. Arcenegui, F. García-Orenes, J. Mataix-Solera e J. Mataix-Beneyto. "Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters". Solid Earth 4, n. 1 (7 marzo 2013): 119–27. http://dx.doi.org/10.5194/se-4-119-2013.
Testo completoAbstract (sommario):
Abstract. The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. These indices represent the balance reached among properties in "steady state" soils. This study was carried out in four study sites from SE Spain irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.
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Morugán-Coronado, A., V. Arcenegui, F. García-Orenes, J. Mataix-Solera e J. Mataix-Beneyto. "Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters". Solid Earth Discussions 4, n. 2 (12 dicembre 2012): 1485–509. http://dx.doi.org/10.5194/sed-4-1485-2012.
Testo completoAbstract (sommario):
Abstract. The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships, the equilibrium reached and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. This study was carried out in three areas of Alicante Province (SE Spain) irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.
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Jamnická, G., Ľ. Ditmarová, D. Kurjak, J. Kmeť, E. Pšidová, M. Macková, D. Gömöry e K. Střelcová. "The soil hydrogel improved photosynthetic performance of beech seedlings treated under drought". Plant, Soil and Environment 59, No. 10 (2 ottobre 2013): 446–51. http://dx.doi.org/10.17221/170/2013-pse.
Testo completoAbstract (sommario):
The effect of soil amendment with the STOCKOSORB®500 MICRO hydrophilic polymer on the photosynthetic traits in beech seedlings (Fagus sylvatica L.) during 50 days of dehydration was investigated. Dehydration was detected through osmotic potential (Ψ<sub>s</sub>) in the assimilatory organs of beech seedlings. The addition of Stockosorb positively affected the CO<sub>2</sub> assimilation rate (A) and instantaneous water use efficiency (A/T), for severely drought-treated seedlings. In comparison with irrigated plants, the values of A of non-irrigated plants with Stockosorb substrate decreased by 50%, and in non-irrigated plants with common substrate by 88%. The fast kinetics of chlorophyll a fluorescence indicated chronic photoinhibition under drought treatment without Stockosorb, while no significant changes in maximal quantum efficiency (F<sub>v</sub>/F<sub>m</sub>) were recorded under drought treatment with Stockosorb. The actual quantum efficiency of PSII (Φ<sub>PSII</sub>) markedly decreased in both treatments – with and without Stockosorb, though significant differences were found only between control treatments and drought treatment without Stockosorb. Moreover, the thermal energy dissipation (NPQ) was strongly limited under severe drought stress. The capacity to down regulate PSII functionality through non-photochemical quenching was maintained under drought treatment with Stockosorb. The results indicate that an amendment with soil conditioner significantly improved the photosynthetic performance of drought-stressed beech seedlings.
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Bui Truong, Son, Nu Nguyen Thi e Duong Nguyen Thanh. "An Experimental Study on Unconfined Compressive Strength of Soft Soil-Cement Mixtures with or without GGBFS in the Coastal Area of Vietnam". Advances in Civil Engineering 2020 (30 giugno 2020): 1–12. http://dx.doi.org/10.1155/2020/7243704.
Testo completoAbstract (sommario):
Soft soil is widely distributed in Vietnam, especially in the coastal area. In engineering practice, soft soil cannot be used to build any construction and needs to be improved or treated before building construction. In addition, Vietnam has many pig-iron or thermal power plants, which annually produce a huge amount of granulated blast furnace slag (GBFS). Thus, the use of this material for soft soil improvement needs to be considered. This paper presents experimental results on the unconfined compressive strength (UCS) of three Vietnam’s soft soils treated with Portland cement and Portland cement with ground granulated blast furnace slag (GGBFS). Binder dosage used in this study is 250, 300, and 350 kg/m3 with the three different water/cement ratios of 0.8, 0.9, and 1.0, respectively. The research results showed that the UCS of soil-cement mixtures depends on soil type, water/cement ratio, cement type, and binder content. Accordingly, the unconfined compressive strength increased with the increase of binder contents, the decrease of the natural water content of soft soil, water/cement ratios, and clay content. The highest value of UCS of treated soils was found for the soil at Site II with the Portland cement content, cement GGBFS, and water/cement ratio of 873 kg/m3, 2355 kg/m3, and 0.8, respectively. Besides, for all the three soils and two binder types, the water/cement ratio of 0.8 was found to be suitable to reach the highest UCS values of treated soil. The research results also showed that the UCS of treated soil with cement GGBFS was higher than that of treated soil with Portland cement. This indicated the effectiveness of the use of Portland cement with GGBFS in soft soil improvement. There is great potential for reducing the environmental problems regarding the waste materials from pig-iron plants in Vietnam and the construction cost as well.
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Lambie, S. M., L. A. Schipper, M. R. Balks e W. T. Baisden. "Carbon leaching from undisturbed soil cores treated with dairy cow urine". Soil Research 50, n. 4 (2012): 320. http://dx.doi.org/10.1071/sr12055.
Testo completoAbstract (sommario):
Solubilisation of soil carbon (C) under cow urine patches may lead to losses of soil C by priming or leaching. We investigated the solubilisation and bioavailability of soil C in undisturbed pasture soil treated with urine. We also studied the contribution of acid-neutralising capacity (ANC) forcing and aggregate disruption as mechanisms of soil C solubilisation. Undisturbed soil cores (0–5 cm; Typic Udivitrand) were treated with water or δ13C-enriched urine and subsequently leached. Urine deposition increased total C and dissolved organic C leaching by 8 g C m–2 compared with water. Soil C contributed 28.1 ± 0.9% of the C in the leachate from urine-treated cores (ULeachate). ANC forcing of urine was 11.8 meq L–1 and may have contributed to soil C leaching, but aggregate disruption was unlikely to have contributed. The bioavailability of organic C in ULeachate was four times greater than in both cow urine and water leachate. It is possible that ULeachate may lead to priming of soil C decomposition lower in the profile. Further testing under field conditions would determine the long-term contribution of urine deposition to dissolved organic C leaching and the fate of solubilised C in pastoral soils.
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Pini, Roberto, Francesca Bretzel, Enzo Sparvoli, Beatrice Pezzarossa e Manuele Scatena. "Compost and Wildflowers for the Management of Urban Derelict Soils". Applied and Environmental Soil Science 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/832608.
Testo completoAbstract (sommario):
The aim of this study was to verify whether the use of source-separated municipal waste compost could improve the physical quality of urban soils and create better conditions for their management when planted with herbaceous species. A sandy soil in traffic islands was tilled to a depth of 10 cm, and half of the surface was treated with compost (3 kg/m2). A mixture of 25 herbaceous annuals was then sown in the entire area. Organic carbon content and physical characteristics were determined at different times in the soil treated and not treated with compost. The vegetation was monitored in terms of its growth and flowering. The compost-treated soil showed an increase in organic carbon content. Total porosity increased with time in the compost-treated soil, due to a higher volume of transmission pores, which play a role in water movement. Soil aggregate stability also improved in the compost-treated soil. The duration of flowering of the individual species and the overall quantity of flowers were greater in the compost-treated soil.
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Kookana, R. S., S. L. Rogers e D. P. Oliver. "Sorption and desorption behaviour of strychnine rodenticide in soils". Soil Research 35, n. 3 (1997): 491. http://dx.doi.org/10.1071/s96070.
Testo completoAbstract (sommario):
Strychnine (Strychnidin-10-one) was used as a rodenticide to control a mouse plague across southern Australia in 1993. Wheat grains were coated with a mixture (containing strychnine, sugar, flour, oil, and a dye) at a rate of 3 g strychnine/kg grain, and were spread as a bait for mice at a density of approximately 3 treated grains/m2. We examined the release of strychnine residue from the treated grains into soils and its sorption–desorption behaviour in 4 different South Australian soils, ranging from sand to clay in texture and acidic to alkaline in reaction. Release studies using treated grains showed that, unless the treated grains were buried in soil, the release of strychnine from the treated grain into soil was slow, requiring about 2 months for its complete transfer into soil. However, upon burial of the treated grain, such as during resowing, the transfer of strychnine from the treated grain to soil was rapid (>90% within 7 days). The sorption of strychnine was found to occur rapidly (>90% of sorption within 15 min). The sorption affinity of strychnine varied by almost 1 order of magnitude among the 4 soils studied. An acidic clay soil (Mintaro) sorbed nearly all (97%) of the applied strychnine, whereas the alkaline sandy soil (Bute) sorbed only 54% of the applied amount, when a strychnine solution 10 mg/L was equilibrated with the soil. Sorption was found to increase substantially with decreasing pHCa from 9 to 7. Indeed, in the 2 soils with relatively higher sorption capacities, nearly 100% of the applied strychnine was sorbed at pHCa 6·5. The pH dependency of sorption was found to follow the proportion of cationic species of strychnine base present in the soil solution. During desorption, hysteresis between the sorption and desorption isotherms of strychnine was noted. The study showed that except in very sandy, alkaline soils, the sorption of strychnine is likely to be high.
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Colinas, C., D. Perry, R. Molina e M. Amaranthus. "Survival and growth of Pseudotsugamenziesii seedlings inoculated with biocide-treated soils at planting in a degraded clearcut". Canadian Journal of Forest Research 24, n. 8 (1 agosto 1994): 1741–49. http://dx.doi.org/10.1139/x94-225.
Testo completoAbstract (sommario):
To determine the component(s) of transfer soils responsible for increased seedling survival and growth, we inoculated planting holes with forest, plantation, and clear-cut soils that were (i) treated with fertilizer to test for effects of nutrients; treated with biocides to test for effects of (ii) microarthropods or nematodes, (iii) protozoa, (iv) fungi, and (v) bacteria; (vi) pasteurized; (vii) Tyndallized; and (viii) untreated. Odds of survival were increased by inoculation with untreated plantation soils, but not if they were fertilized or treated with dimethoate + carbofuran (grazercide), fumagillin (protozoacide), or oxytetracycline + penicillin (bactericide). Addition of untreated forest soil did not increase survival. For all soils, survival odds were increased by captan (fungicide), pasteurization, and Tyndallization. Treatments affected seedling dry weights differently than survival. Untreated plantation and forest soil transfers increased dry weights whereas neither did when treated with dimethoate + carbofuran. Dry weights of seedlings given clear-cut soil were increased by fertilization, pasteurization, and Tyndallization of the soil; the latter two treatments also increased the number of short roots. We hypothesize that stimulation of seedling growth by soil transfers was related to an increased rate of nutrient mineralization due to microbivorous soil animals contained within the transfer soils. Soil transfers may have enhanced seedling survival by at least two mechanisms: (i) by providing a safe site for beneficial rhizosphere organisms to proliferate, free from competing organisms that have proliferated in the clear-cut soil; (ii) through volatile organic compounds that stimulated seedling root growth, especially ethylene, which previous studies have shown to be produced at significantly lower rates in soils of the clear-cut compared with adjacent forest soils. Further research is needed to distinguish between these possibilities.
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Moretti, Sarah Mello Leite, Edna Ivani Bertoncini e Cassio Hamilton Abreu-Junior. "Carbon Mineralization in Soils Irrigated with Treated Swine Wastewater". Journal of Agricultural Science 9, n. 3 (13 febbraio 2017): 19. http://dx.doi.org/10.5539/jas.v9n3p19.
Testo completoAbstract (sommario):
Treated swine wastewater agricultural use can promote environmental and agronomical improvements, however, the inappropiate management of this organic load added on soil can cause unbalances in soil fertility and in availability of nutrients and/or contaminants. Thus, this study aim was evaluate the organic matter biodegradation of treated swine wastewater (WB) and diluted swine wastewater (WBD) applied in Oxisol clayey texture (CS) and in Ultisol (SS) with medium-sandy texture. The treatments studied were: R1 – CS control; R2 – irrigation with WB on CS; R3 – irrigation with WBD on CS; R4 – SS control; R5 – irrigation with WBD on SS; R6 – irrigation with WBD on SS. Three applications were done in flasks containing 500 g of soils sampled from depth of 0-20 cm, the C-CO2 evolutions and degradation fractions were quantified after each application. The results obtained were adjusted to first-order chemical kinetics model. More than half organic matter was biodegraded between 4 and 10 days of incubation, when higher WB amount was applied (33.3 mm). Sucessive WBD use caused degradation of organic matter remaning of previous application. Higher CO2 evolutions were obtained for Oxisol treatments due to higher carbon contents of this soil. SW use caused depletion of Ultisol native organic matter. However, the WB use in Oxisol provided accumulation of organic matter. Soon, the respirometry test evidenced the importance of evaluate the soil depuration capacity before agricultural use, since that this process can affect the contents of organic matter native of these soils and the availabity of nutrient/contaminant for soil-water-plant system.
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Zhang, Xike, e Zdenko Rengel. "Role of soil pH, Ca supply, and banded P fertilisers in modulating ammonia toxicity to wheat". Australian Journal of Agricultural Research 51, n. 6 (2000): 691. http://dx.doi.org/10.1071/ar99071.
Testo completoAbstract (sommario):
Di-ammonium phosphate (DAP) and mono-ammonium phosphate (MAP) banded close to seed may cause ammonia (NH 3 ) toxicity by inhibiting seed germination and early seedling growth. A pH increase around the fertiliser band and/or limited Ca supply may exaggerate ammonia toxicity. In the current study, wheat growth and gradients of pH, electrical conductivity (EC), ammonium (NH 4 + ), and P concentration in soil were studied by comparing banded DAP + urea or MAP + urea fertilisers in control or gypsum- or CaCO 3 -treated Lancelin soil. After 21 days of wheat growth, visual symptoms of ammonia toxicity appeared in the gypsum-treated and control plants, but not in the CaCO 3 -treated plants. The symptoms were more severe in the MAP treatments than in DAP treatments. An addition of CaCO 3 increased soil pH CaCl2 from 5.1 to 7.3, and the ammonium concentration was lower than that in the gypsum-treated and control soils. In the gypsum-treated and control soils, pH increased by nearly 1 unit in the vicinity of the DAP or MAP band. In contrast, soil pH decreased in the location of the DAP or MAP band in the CaCO 3 -treated soil. Banding of MAP or DAP in the gypsum-treated soil caused an increase in soil EC. The good plant growth on the soil amended with CaCO 3 might have been related to the low ammonium concentration in the soil and the high concentration of Ca. Gypsum and CaCO3 decreased the availability of P supplied in the MAP or DAP band. It was concluded that increased pH and higher Ca content in sandy soil may alleviate ammonia toxicity to wheat.