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1
Ibarra-Jiménez, L., J. Munguía-López, A. J. Lozano-del Río, and A. Zermeño-González. "Effect of plastic mulch and row covers on photosynthesis and yield of watermelon." Australian Journal of Experimental Agriculture 45, no. 12 (2005): 1653. http://dx.doi.org/10.1071/ea04140.
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The effect of row covers on watermelon (Citrullus vulgaris) grown on plastic mulch is well documented. However, row covers have not been adequately evaluated under Mexican growing conditions. Watermelon plants were grown on plastic mulch alone or with row covers to study their effect on photosynthesis, and early and total yields. Treatments were clear plastic mulch (C); black plastic mulch (B); B plus a Vispore cover of polypropylene (BV); B plus a white cover of perforated polyethylene (BW); B plus a clear cover of perforated polyethylene (BC); B plus an Agribon cover of polypropylene (BA); and bare soil as the control. For plants grown in treatment C, B or B combined with row covers, plant dry weight and number of leaves 40 days after seeding (DAS) were higher than the control (P<0.05), except BC which was comparable to the control. Total yields of treatments C, B, BV, BW and BA differed (P<0.05) from BC and the control. Total yields increased by 46.1, 43.2, 35.7, 41.6, 13.3, 15.4 and 35.8 t/ha for the C, B, BV, BW, BC and BA treatments, respectively, over the control, which yielded 27.1 t/ha. Total yield was highest for the C and the B treatment suggesting that there was no need for additional covers. The number of leaves per plant or dry weight per plant better explains the changes in yield than net photosynthesis rate. Stomatal conductance was explained in part by changes in photosynthesis.
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Ibarra-Jiménez, L., M. R. Quezada-Martín, and M. de la Rosa-Ibarra. "The effect of plastic mulch and row covers on the growth and physiology of cucumber." Australian Journal of Experimental Agriculture 44, no. 1 (2004): 91. http://dx.doi.org/10.1071/ea02088.
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To determine the effectiveness of black plastic mulch alone and in combination with row covers, on growth and physiological changes of cucumber plants, 6 treatments were established in a randomised complete block design with 4 replications: bare soil (control); black polyethylene mulch alone (B); B plus a clear cover of perforated polyethylene (BRCP); B plus a white cover of perforated polyethylene (BRWP); B plus an Agribon cover of polypropylene (BRA); and B plus a Kimberly farm row cover (BRK). For the plants grown with mulch or mulch combined with row covers, the dry weight of leaves 50 days after seeding (DAS), and the dry weight of whole plants (at 50 and 110 DAS) were significantly (P<0.05) different from the control. Early yields of treatments B, BRCP, BRWP, BRA and BRK were 2.1, 1.9, 2.6, 1.9 and 2.4 times higher than the control, which yielded 10 t/ha. Total yields were increased by 9.7, 15.4, 19.8, 14.9 and 20 t/ha, over the control which yielded 104 t/ha. Increases in plant dry weight explained the changes in yield. Stomatal conductance may explain in part, the increase in photosynthetic rate, but may not explain yield increase.
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Stang, Elden J., and John Klueh. "SPUNBONDED FABRIC COVERS ALTER EARLY SEASON GROWTH AND FRUIT SET IN CRANBERRY." HortScience 25, no. 9 (September 1990): 1105c—1105. http://dx.doi.org/10.21273/hortsci.25.9.1105c.
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Spunbonded polypropylene fabric covers were applied over mature `Searles' cranberry (Vaccinium macrocarpon Ait. in the field during dormancy in 1989. Covers were selectively removed at 3 week intervals in April, May and early June after onset of growth. Plant canopy air temperatures under fabric were 5 to 6C higher than in exposed controls. Temperature differences up to 17C were measured in early June. Soil temperatures did not differ from the control until late May. Earlier greening of leaf tissue resulted in increased photosynthetic rates earlier in the growing season under fabric covers. Subsequent shoot dry weight was increased 5%; leaf size was not affected. A trend to increased fruit set (4 to 6%) with fabric cover treatments was observed when covers were applied for 6 or 9 weeks. Total fruit yield and anthocyanin content were not appreciably influenced by fabric covers.
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Dieser, Markus, Andreas Nocker, John C. Priscu, and Christine M. Foreman. "Viable microbes in ice: application of molecular assays to McMurdo Dry Valley lake ice communities." Antarctic Science 22, no. 5 (June 23, 2010): 470–76. http://dx.doi.org/10.1017/s0954102010000404.
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AbstractThe permanent ice covers of the McMurdo Dry Valley lakes, Antarctica, are colonized by a diverse microbial assemblage. We collected ice cores from Lakes Fryxell, Hoare and Bonney. Propidium monoazide (PMA) was used in combination with quantitative PCR (qPCR) and denaturing gradient gel electrophoresis (DGGE) to examine membrane integrity of prokaryotes in these extreme environments. PMA selectively penetrates cells with compromised membranes and modifies their DNA resulting in the suppression of PCR amplification. Our results based on analysis of 16S rRNA genes demonstrate that despite the hostile conditions of the Dry Valleys, the permanent ice covers of the lakes support a ‘potentially viable’ microbial community. The level of membrane integrity, as well as diversity, was higher in samples where sediment was entrapped in the ice cover. Pronounced differences in the fraction of cells with intact and compromised cell membranes were found for Lake Fryxell and east lobe of Lake Bonney, both expressed in differences in DGGE banding patterns and qPCR signal reductions. Limitations in the ability to distinguish between intact or compromised cells occurred in samples from Lake Hoare and west lobe of Lake Bonney due to low DNA template concentrations recovered from the samples.
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Mylona, Evangelia, Anthimos Xenidis, Mihály Csövári, and Gábor Németh. "Application of dry covers for the closure of tailings facilities." Land Contamination & Reclamation 15, no. 2 (April 1, 2007): 163–82. http://dx.doi.org/10.2462/09670513.849.
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Jiménez-Rodríguez, César, Catalina Esquivel-Vargas, Miriam Coenders-Gerrits, and Mahmood Sasa-Marín. "Quantification of the Evaporation Rates from Six Types of Wetland Cover in Palo Verde National Park, Costa Rica." Water 11, no. 4 (April 1, 2019): 674. http://dx.doi.org/10.3390/w11040674.
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The hydrology of tropical seasonal wetlands is affected by changes in the land cover. Changes from open water towards a vegetated cover imply an increase in the total evaporation flux, which includes the evaporation from open water bodies and the transpiration from vegetated surfaces. This study quantified the total evaporation flux of six covers of the Palo Verde wetland during dry season. The selected wetland covers were dominated by Neptunia natans (L.f.) Druce, Thalia geniculata L., Typha dominguensis Pers., Eichhornia crassipes (Mart.) Solms, a mixture of these species, and open water conditions. The plants were collected from the wetland and placed in lysimeters (59.1 L) built from plastic containers. The lysimeters were located in an open area near the meteorological station of the Organization for Tropical Studies (OTS). The evaporated water volume and meteorological data were collected between December 2012–January 2013. A completely randomized design was applied to determine the total evaporation (E), reference evaporation ( E ref , Penman-Monteith method) and crop coefficient ( K c ) for all the covers. T. geniculata (E: 17.0 mm d − 1 , K c : 3.43) and open water (E: 8.2 mm d − 1 , K c : 1.65) showed the highest and lowest values respectively, for daily evaporation and crop coefficient. Results from the ANOVA indicate that E. crassipes and N. natans were statistically different (p = 0.05) from T. dominguensis and the species mixture, while the water and T. geniculata showed significant differences with regard to other plant covers. These results indicate that the presence of emergent macrophytes as T. geniculata and T. dominguensis will increase the evaporation flux during dry season more than the floating macrophytes or open water surfaces.
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Germer, Jörn. "Effect of transparent covers for collection chambers of urine-diverting dry toilets on dehydration of faecal waste." Journal of Water, Sanitation and Hygiene for Development 1, no. 3 (September 1, 2011): 195–203. http://dx.doi.org/10.2166/washdev.2011.032.
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Urine-diverting dry toilets save water, reduce the demand for wastewater treatment and provide plant nutrients. The conditions in the collection chambers and the interlinked hygienic safety of subsequent faecal matter use in crop production are affected by the building design. Comparative experiments were carried out to evaluate the potential of transparent chamber covers in comparison with non-transparent chamber covers to increase temperature and ventilation in order to enhance faecal matter dehydration and sanitation. The air temperature in the chambers with transparent covers (TC) was 1.1–1.5 °C higher and the relative air humidity about 5–7% lower than in chambers with non-transparent covers. The advantage of TCs on temperature and humidity prevailed throughout the year, but was most pronounced in months with more sunshine hours and higher irradiation. Furthermore, the airflow out of the chambers through the ventilation pipes was increased by 60% in the TCs. During two-month collection and dehydration cycles the improved drying conditions in the TCs resulted in 7% lower faecal matter moisture. A trend towards an enhanced pathogen inactivation in the faecal material was observed. The results demonstrate that in the semi-arid tropics transparent covers for collection chamber of urine diverting dry toilets improve the dehydration of faecal matter.
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Casierra-Posada, Fánor, Esteban Zapata-Casierra, and Daniel A. Chaparro-Chaparro. "Growth analysis in chard plants (Beta vulgaris L. Cicla, cv. 'Pencas Blancas') exposed to different light quality." Agronomía Colombiana 32, no. 2 (May 1, 2014): 205–12. http://dx.doi.org/10.15446/agron.colomb.v32n2.42640.
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To determine the effects of light quality on the growth indices of plants, Pencas Blancas cultivar chard plantlets were grown for 2 months under five different light treatments, obtained by filtering sunlight through colored polyethylene films. The treatments included: red, blue, green, yellow and transparent cover colors. A transparent cover (white light) was used as the control. The colored covers affected the plant growth. The plants grown under the yellow cover presented a better behavior with regards to growth, taken as: total dry weight per plant, leaf area, specific leaf area, absolute growth rate, relative growth rate, harvestable dry matter and root to shoot ratio. The dry matter partitioning in the leaves and roots was affected by the light quality, but not in the petioles, with a higher accumulation of dry mass in the leaves of plants grown under the yellow cover. As a consequence of the enhanced leaf area in the plants under the yellow cover, they also had the highest water uptake. On the other hand, the highest net assimilation rate value was found in plants grown under the transparent cover. These results open up the possibility of using yellow colored cover in leafy green vegetables, especially in chard plants grown under controlled conditions.
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Calheiros, Altanys Silva, Mario de Andrade Lira Junior, Mércia Virgínia Ferreira Santos, and Maria do Carmo Catanho Pereira Lyra. "SYMBIOTIC EFFECTIVENESS AND COMPETITIVENESS OF CALOPO RHIZOBIAL ISOLATES IN AN ARGISSOLO VERMELHO-AMARELO UNDER THREE VEGETATION COVERS IN THE DRY FOREST ZONE OF PERNAMBUCO." Revista Brasileira de Ciência do Solo 39, no. 2 (April 2015): 367–76. http://dx.doi.org/10.1590/01000683rbcs20140393.
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Biological N fixation in forage legumes is an important alternative to reduce pasture degradation, and is strongly influenced by the inoculant symbiotic capability. This paper evaluates the effectiveness of Calopo (Calopogonium mucunoides) rhizobial isolated from soil under three vegetation covers of an Argissolo Vermelho-Amarelo of the Dry Forest Zone of Pernambuco. An experiment was conducted evaluating 25 isolates, aside from 5 uninoculated controls with 0; 309; 60; 90 and 120 kg ha-1 N, and a treatment inoculated with the SEMIA 6152 strain. The first cut was performed 45 days after inoculation and a second and third cut after 45-day-intervals. Shoot N content was quantified at all cuts. Shoot dry mass was affected by N rates at all cuts. Shoot dry mass increased from the first to the second cut in inoculated plants. There was no difference between rhizobial isolates from the different plant covers for any of the variables. Most variables were significantly and positively correlated.
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Henderson-Cole, Janet C., and Michael A. Schnelle. "Effect of Prodiamine and Oxadiazon on Growth of Bedding Plants and Ground Covers." Journal of Environmental Horticulture 11, no. 1 (March 1, 1993): 17–19. http://dx.doi.org/10.24266/0738-2898-11.1.17.
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Abstract Four bedding plant species, rose periwinkle, petunia, geranium, and scarlet salvia; four ground cover cultivars, golden Japanese barberry, common periwinkle, Bowles periwinkle, and greater periwinkle; and pots seeded with two weed species, crabgrass or pigweed were sprayed with 0, 1.1 or 4.5 kg ai/ha (0, 1.0 or 4.0 lb/A) prodiamine (Barricade) or 2.2 kg ai/ha (2.0 lb/A) oxadiazon (Ronstar). Heights or dry weights or both of all bedding plant species decreased linearly with increasing prodiamine (Barricade) application rates. Ground covers were not affected by oxadiazon (Ronstar) or prodiamine (Barricade) except for a reduction in root dry weight of common periwinkle with prodiamine (Barricade) applications. Crabgrass and pigweed were completely controlled by prodiamine (Barricade) throughout the growing season, but oxadiazon (Ronstar) lost its effectiveness after three months.
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Dobrovolskaya, Yekaterina V., Henry Wai Chau, and Bing Chen Si. "Improving water storage of reclamation soil covers by fractionation of coarse-textured soil." Canadian Journal of Soil Science 94, no. 4 (August 2014): 489–501. http://dx.doi.org/10.4141/cjss2013-086.
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Dobrovolskaya, Y. V., Chau, H. W. and Si, B. C. 2014. Improving water storage of reclamation soil covers by fractionation of coarse-textured soil. Can. J. Soil Sci. 94: 489–501. Mining operations cause considerable land disturbance as well as the accumulation of large amounts of waste rock. Capping waste rock with a soil cover has proven to be a reliable, long-term reclamation technique. This study examines the question of whether it is possible to attain a considerable increase in water storage capacity (WSC) by separating coarse-textured soil into particle size fractions and layering them into a soil cover. Additionally, this study investigated whether preferential flow can be mitigated by increasing the number of layers and extending the interlayer transitions in fine-over-coarse-textured soil systems. Intermittent and constant infiltration experiments were conducted on homogeneous covers composed of natural sand, two-layered covers with abrupt and gradual interlayer transitions as well as on a four-layered cover under initially air-dry and field capacity (FC) conditions. Water storage capacities were determined from a sampling of soil covers’ water content at FC. Infiltration experiments showed that all tested covers under all initial and boundary conditions had limited susceptibility to preferential flow. Increasing the number of layers and extending the interlayer transitions had a stabilizing effect on the wetting front. Water storage capacities and residence time increased with the increased number of layers. Overall, it has been shown that it is possible to improve the WSC of coarse-textured soil by fractionation and layering of it into a relatively fine-over-coarse soil system.
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Hartley, M. J., A. Rahman, K. C. Harrington, and T. K. James. "Assessing ground covers in a newly planted apple orchard." New Zealand Plant Protection 53 (August 1, 2000): 22–27. http://dx.doi.org/10.30843/nzpp.2000.53.3643.
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Three low growing groundcover species dichondra (Dichondra micrantha) hydrocotyle (Hydrocotyle heteromeria) and a creeping red fescue (Festuca rubra)/white clover (Trifolium repens) mixture were compared to bark mulch and herbicide in a newly planted apple orchard for their ability to suppress weeds Dichondra with the aid of an initial herbicide treatment established a dense ground cover and provided good weed suppression Hydrocotyle failed to establish under the dry Hawkes Bay conditions Creeping red fescue gave moderate weed suppression Bark required spot treatment with herbicide for complete weed control All ground covers reduced tree growth and fruit yield in the first year compared to herbicide and bark mulch
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Aubertin, M., E. Cifuentes, S. A. Apithy, B. Bussière, J. Molson, and R. P. Chapuis. "Analyses of water diversion along inclined covers with capillary barrier effects." Canadian Geotechnical Journal 46, no. 10 (October 2009): 1146–64. http://dx.doi.org/10.1139/t09-050.
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Various types of cover systems can be used to control water infiltration into waste disposal sites. One promising option is to combine different types of soil to create a layered cover with capillary barrier effects (CCBE). A CCBE basically involves the placement of a relatively fine-grained soil, which acts as a water-retention layer, over a coarser capillary break material. On slopes, a CCBE promotes lateral water diversion. Inclined CCBEs, however, are relatively complex, as their behaviour is influenced by numerous factors. In this paper, the authors present the key results obtained from a numerical investigation into the response of steeply inclined CCBEs. The study evaluates the behaviour of covers under dry and humid climatic conditions. After a review of the physical processes and background studies, the paper presents simulation results that demonstrate the effect of key factors on the diversion length of covers, including layer thicknesses, material properties, and recharge rates. The results shown here indicate that increasing the thickness of the cover may improve its efficiency, but only up to a certain maximum beyond which the gain becomes minimal. These results should be of help to those involved in the design of inclined CCBEs.
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Siwek, Piotr, Andrzej Libik, and Izabela Zawiska. "The effect of biodegradable nonwovens in butterhead lettuce cultivation for early harvest." Folia Horticulturae 24, no. 2 (December 1, 2012): 161–66. http://dx.doi.org/10.2478/v10245-012-0020-2.
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Abstract Field experiments using ‘melt-blown’ biodegradable nonwovens were carried out on the ‘Melodion’ butterhead lettuce (Lactuca sativa var. capitata L.) cultivar for early harvest. All biodegradable nonwovens were manufactured in the Institute of Biopolymers and Chemical Fibres and POLMATEX CENARO in Łódź, Poland. Lettuce seeds were sown into boxes in a greenhouse at the beginning of March, and transplants were planted into the field at the beginning of April. Biodegradable nonwovens - aromatic polyester IBWCH 75 g m-2, polybutylene succinate Bionolle 100 g m-2 and standard polypropylene PP Agro 20 g m-2 - were stretched over the lettuce in the field. The covers were kept on until 4-5 days before harvest. Plots without covers were defined as the control. Ascorbic acid, soluble sugar, dry matter, nitrates, chlorophyll a, chlorophyll b and carotenoid contents were recorded in the leaves. All biodegradable nonwovens showed a positive effect on yielding in comparison to the control in 2009. In the second year of the experiment, there were no significant differences between covers with regard to the yield. Dry matter and soluble sugar content in both years of the experiment was diversified. Nonwovens used as covers in 2009 significantly increased the content of nitrates in comparison to the control. In the second year, the highest level of nitrates was demonstrated in the control object. It is worth underlining that the maximum allowed limit of nitrate content in lettuce (4000 mg kg f.w.) was not exceed. The kind of cover had no significant effect on the level of chlorophyll a in 2009 or chlorophyll b and carotenoids in 2009 and 2010 in the lettuce
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Zawiska, Izabela, and Piotr Siwek. "The effect of biodegradable direct covers on the root development, yield and quality of cucumber." Folia Horticulturae 26, no. 1 (June 1, 2014): 43–48. http://dx.doi.org/10.2478/fhort-2014-0004.
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ABSTRACT The results of three years (2009-2011) of field studies using two types of biodegradable nonwoven covers (aromatic polyester IBWCH 75 g m-2 and polylactic acid PLA 54 g m-2) on the yield, quality and root development of cucumber are presented. Seeds of parthenocarpic cucumber (‘Mirabelle’ F1) were sown directly into the field at the beginning of May/June and covered with nonwoven field covers. A plot that remained uncovered served as the control. The covers were kept in place until the first flowers appeared. Cucumbers were harvested every three days for 5-6 weeks. Fruits were evaluated for dry matter, soluble sugars and nitrate content. After the last harvest, whole plants were harvested and evaluated for weight, surface area, total length and average diameter of the roots. The experiment showed that the covers increased the marketable yield of cucumber in 2009 and 2010 (regardless of the type of polymer), but did not influence the yield in 2011. In 2011 the fruits from the covered plots had higher levels of soluble sugars and dry matter in comparison to the control. The covers did not influence root development.
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Wang, Peng, Licheng Shen, Xiaohong Chen, Zhijun Wang, Xuan Liang, Bill X. Hu, Jiacheng Lan, and Xinxin Zhai. "Response of soil water hydrochemistry and δ13CDIC to changes in spatio-temporal variations under different land covers in SW China karst catchment." Hydrology Research 50, no. 3 (February 26, 2019): 925–44. http://dx.doi.org/10.2166/nh.2019.061.
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Abstract Soil water plays a crucial role in biogeochemical processes within karst ecosystems. However, geochemical variations of soil waters under different land covers and the related karst critical zone processes are still unclear. In this study, five land covers, including grassland, dry land, shrub land, reforestation land, and bamboo land in the Qingmuguan karst area of Chongqing Municipality, Southwest (SW) China were investigated in order to better understand the spatio-temporal variations of soil water geochemistry and its controlling mechanisms. The hydrochemistry of soil water and stable carbon isotopic compositions of dissolved inorganic carbon (δ13CDIC) in soil water were analyzed by a semi-monthly sampling strategy. The results show that there is remarkable spatio-temporal variation in the hydrochemistry and δ13CDIC of soil waters under different land covers in the studied area. Soil waters collected from shrub, dry, and afforestation lands have higher total dissolved solids (TDS), Ca2+, and HCO3− concentrations and heavier δ13CDIC, which is probably associated with the stronger carbonate dissolution caused by higher soil CO2 and carbonate content in soils under these land covers. However, lower TDS, Ca2+, and HCO3− concentrations as well as δ13CDIC values but higher SO42− concentrations are found in soil waters collected from bamboo land and grassland. The reason is that higher gypsum dissolution or oxidation of sulfide minerals and less soil CO2 input occurs in soils under these two land covers. Under the shrub, dry, and afforestation lands, higher concentrations of Ca2+ and HCO3− in soil waters occur in rainy seasons than in dry seasons, which are probably linked to higher CO2 input due to stronger microbial activities and root respiration in the wet summer seasons. In addition, seasonal variations of NO3− concentrations in soil waters from the dry land are observed, and much higher NO3− concentration occurs in the rainy seasons than that in the dry seasons, which suggest that the agricultural fertilization may lead to high NO3− in soil water. On the vertical soil profile, except for the bamboo land, soil waters under different land covers commonly show an increasing trend of main ion concentrations with the increase of depth. This vertical variation of hydrochemistry and δ13CDIC values in soil waters is primarily controlled by the intensity of carbonate dissolution related to carbonate content in soils and soil CO2 production. The soil waters under different land covers have great variations in δ13CDIC values which ranged from −20.68‰ to −6.90‰. Also, the [HCO3−]/([Ca2+] + [Mg2+]), [NO3−]/[HCO3−], and [SO42−]/([Ca2+] + [Mg2+]) molar ratios in soil waters show a large amplitude of variation. This suggested that carbonic acids could not be a unique dissolving agent and sulfuric/nitric acids may play a role in the weathering of carbonate in the Qingmuguan karst area.
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Kosterna, E. "The yield and quality of broccoli grown under flat covers with soil mulching." Plant, Soil and Environment 60, No. 5 (May 7, 2014): 228–33. http://dx.doi.org/10.17221/168/2014-pse.
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The experiment was carried out between 2010 and 2012. Effect of plants covering and the kind of organic mulch applied to soil mulching on the yield and selected component of nutritive value in Milady F<sub>1</sub> broccoli cultivated for early harvest was investigated. The application of polypropylene fibre contributed to a significant increase in the marketable yield of broccoli on average by 5.25 t/ha, weight of head by 0.10 kg and length of arc by 1.44 cm. Increase of the content of chemical components as a result of plants covering amounted to 1.76% for dry matter, 2.50 mg/100 g fresh matter (FM) for ascorbic acid, 0.65% FM for total sugar and 0.15% FM for monosaccharides. All kinds of straw contributed to an increase in the broccoli yield and improvement its parameters. The highest marketable yield and weight of head was obtained in the plots mulched with buckwheat straw. Irrespective of covering, cultivation on the mulch with buckwheat straw contributed to a slight decrease in dry matter, total sugars content, whereas cultivation on the rye straw decreased ascorbic acid content.
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Kalisz, Andrzej, Agnieszka Sękara, Aneta Grabowska, Konrad Sulak, Ewa Capecka, Andrzej Libik, Rita Jurkow, and Bogdan Kulig. "PERFORMANCE OF BIODEGRADABLE FLOATING DIRECT COVERS IN THE FIELD PRODUCTION OF BUTTERHEAD LETTUCE DURING SPRING AND AUTUMN TRIALS." Acta Scientiarum Polonorum Hortorum Cultus 20, no. 2 (April 28, 2021): 93–106. http://dx.doi.org/10.24326/asphc.2021.2.10.
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Non-degradable polypropylene nonwovens are difficult to dispose and their utilization represents high economic costs. This study was conducted on lettuce cultivated during the spring and autumn seasons in the southern part of Poland to test biodegradable nonwovens as plant covers. Several nonwovens were developed from aliphatic-aromatic copolyesters (ACC), one without modifiers (SB48/11) and three with the addition of fatty acid dimers: two commercial variants (SB20/13, SB21/13) and one made from plant biomass (SB28/13). Nonwoven polypropylene (PP) fleece was included as a control cover. One week after covering with SB48/11, stomatal conductance (gs) increased in lettuce plants in parallel with higher transpiration rate (E) and sub-stomatal CO2 concentration (Ci) relative to the control, but differences in these parameters evened out in mature plants. In the spring, degradable covers with their higher mass per unit area, caused a decrease in marketable yield of lettuce compared to the control PP, resulting mainly from the deterioration of plant quality and lower mean weight per head. In the autumn season, yield was statistically not different between treatments. Yield of spring lettuces was 78% higher compared to the autumn cultivation period. Plants grown under SB20/13 had the lowest dry weight and L-ascorbic acid, while plants under SB21/13 had the highest dry weight and L-ascorbic acid content. Plants under SB28/13 had higher chlorophyll a content. Generally, no effect of covers was noted for carotenoid concentrations. The content of dry weight, L-ascorbic acid, and carotenoids were higher in plants harvested in spring, while no effects of crop season on chlorophyll level were observed. All tested biodegradable nonwovens are a potential substitute for standard polypropylene in autumn trials, but for spring covering unit weight of these materials should be reduced.
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Giambelluca, T. W., J. Fox, S. Yarnasarn, P. Onibutr, and M. A. Nullet. "Dry-season radiation balance of land covers replacing forest in northern Thailand." Agricultural and Forest Meteorology 95, no. 1 (May 1999): 53–65. http://dx.doi.org/10.1016/s0168-1923(99)00016-7.
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Lu, Jimnei, Lena Alakangas, Yu Jia, and Jenny Gotthardsson. "Evaluation of the application of dry covers over carbonate-rich sulphide tailings." Journal of Hazardous Materials 244-245 (January 2013): 180–94. http://dx.doi.org/10.1016/j.jhazmat.2012.11.030.
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Bender, David A. "SEEDING AND COVERING DATES FOR PRODUCING `TEXAS GRANO 1015Y' ONION TRANSPLANTS UNDER ROW COVERS." HortScience 29, no. 7 (July 1994): 731f—731. http://dx.doi.org/10.21273/hortsci.29.7.731f.
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Field production of adapted transplants could allow West Texas growers to meet the strong demand for `Texas Grano 1015Y' onions in June. A trial was conducted to determine optimal timing for seeding and covering field beds with row covers to produce transplants for planting in early March. Onions were seeded in drip-irrigated field beds at 10-day intervals from mid-October to mid-November and covered with 4-mil polyethylene tunnels at 10-day intervals from mid-November to mid-December. Plants were evaluated on 11 March and transplanted into field plots with greenhouse-grown plants. Seeding in October or covering in mid-November produced acceptable 4-leaf transplants by early March. Plant height, dry weight, number of leaves and survival decreased as seeding or covering was delayed. In field trials, row cover plants produced equal yields and only slightly smaller bulbs than greenhouse plants. Despite the large size of some of the field-grown transplants, no bolting was observed.
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Fukami, Hiroshi, Kenji Kojima, and Hideaki Aburakawa. "The Extinction and Absorption of Solar Radiation Within a Snow Cover." Annals of Glaciology 6 (1985): 118–22. http://dx.doi.org/10.3189/1985aog6-1-118-122.
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A device capable of measuring the extinction coefficient of solar radiation within the snow cover was developed, using small silicone photocells as sensors. Extinction coefficient measured for natural snow covers in the field was 37-97 m-1 for dry snow of density 90-470 kg m-3. It decreased in the process of metamorphism from new snow to slightly compacted snow, and increased in the process of settlement from slightly compacted to compacted snow. It was 23-58 m-1 for wet snow of density 430-530 kg m-3 and in water content from 5-15%, being smaller than that for dry snow of the same density. The authors also determined local temperature increase of snow cover related to absorption of solar radiation. The temperature profile within the snow cover was calculated by solving the equation of heat conduction including the term of absorption of radiative energy. Measured and calculated snow temperatures agreed well, indicating the accuracy of the extinction measurements.
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Fukami, Hiroshi, Kenji Kojima, and Hideaki Aburakawa. "The Extinction and Absorption of Solar Radiation Within a Snow Cover." Annals of Glaciology 6 (1985): 118–22. http://dx.doi.org/10.1017/s0260305500010132.
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A device capable of measuring the extinction coefficient of solar radiation within the snow cover was developed, using small silicone photocells as sensors. Extinction coefficient measured for natural snow covers in the field was 37-97 m-1 for dry snow of density 90-470 kg m-3. It decreased in the process of metamorphism from new snow to slightly compacted snow, and increased in the process of settlement from slightly compacted to compacted snow. It was 23-58 m-1 for wet snow of density 430-530 kg m-3 and in water content from 5-15%, being smaller than that for dry snow of the same density. The authors also determined local temperature increase of snow cover related to absorption of solar radiation. The temperature profile within the snow cover was calculated by solving the equation of heat conduction including the term of absorption of radiative energy. Measured and calculated snow temperatures agreed well, indicating the accuracy of the extinction measurements.
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Vargas, Pablo Forlan, Amanda Chiarion Zecchini, Renato Silva Soares, Leonardo Dos Santos Duarte, and Edgard Henrique Costa Silva. "Performance of crispy lettuce cultivars in different soil covers." Comunicata Scientiae 8, no. 4 (April 12, 2018): 514–20. http://dx.doi.org/10.14295/cs.v8i4.1942.
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The lettuce cropping is an important segment of the national agriculture, with strong economic expression. However, climatic factors such as high temperature and humidity can affect this vegetable cultivation. These environmental conditions are common in various Brazilian regions, so the growers should adopt crop management systems, as soil covers, to minimize the environmental effect and obtain higher returns. Thus, the aim of this study was to evaluate the influence of different soil covers on the agronomic performance of crispy lettuce cultivars. The study was conducted at UNESP, Registro Campus, Brazil, from August to October, 2013. The experiment was carried out in a randomized blocks design, arranged in a 4x4 factorial, with three repetitions. The treatments consisted of the factors soil covers (black mulching, silver mulching, white mulching and control) and cultivars (Inaiá, Milena, Vanda and Vera). The experimental unit consisted of fifteen plants, with the useful area composed of nine central plants. At harvest, the following characteristics were evaluated: plant height, head diameter, fresh mass, number of leaves, leaf width, leaf height, stem diameter, heart diameter, heart height, dry mass, yield and nitrate content. Among the studied covers, white mulching showed the best results for the main productive characteristics and can be used as soil cover in the cultivation of Vera, Vanda and Inaiá culivars.
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G, Thirumaran, Ganesan C.M, and Nandakumar K. "ETHNOMEDICINAL STUDIES ON RIVER STRETCH CAUVERY BASIN OF NANJAI EDAYAR AND KUCHIPALAYAM, NAMAKKAL DISTRICT, TAMIL NADU." Kongunadu Research Journal 1, no. 2 (December 30, 2014): 116–20. http://dx.doi.org/10.26524/krj51.
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The study area covers about 15 km stretch in the perennial river bed, Cauvery which supports semievergreen to dry deciduous types of forests. Ethnomedicinal information on 26 plant species was recorded during the extensive field survey carried out in this stretch during 2011-2013. The information covers botanical names, vernacular names, family, plant parts used and the mode of usage
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Mackowiak, C. L., R. M. Wheeler, G. W. Stutte, N. C. Yorio, and L. M. Ruffe. "A Recirculating Hydroponic System for Studying Peanut (Arachis hypogaea L.)." HortScience 33, no. 4 (July 1998): 650–51. http://dx.doi.org/10.21273/hortsci.33.4.650.
Full textAbstract:
Peanut (Arachis hypogaea L.) plants were grown hydroponically, using continuously recirculating nutrient solution. Two culture tray designs were tested; one tray design used only nutrient solution, while the other used a sphagnum-filled pod development compartment just beneath the cover and above the nutrient solution. Both trays were fitted with slotted covers to allow developing gynophores to reach the root zone. Peanut seed yields averaged 350 g·m-2 dry mass, regardless of tray design, suggesting that substrate is not required for hydroponic peanut production.
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Favarato, Luiz Fernando, Rogério Carvalho Guarçoni, Frederico Jacob Eutrópio, Lidiane Mendes, and Mírian Piassi. "Growth of lettuce cultivars in beds covered with differing materials." REVISTA AGRO@MBIENTE ON-LINE 13 (July 23, 2019): 87. http://dx.doi.org/10.18227/1982-8470ragro.v13i0.5442.
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In commercial lettuce growing, the intensive cultivation of the soil results in an increase in weed populations, making it difficult to fully exploit the area and increasing production costs. Under such
circumstances, the use of soil covers can minimize this problem. Consequently, the objective of this study was to evaluate the effects of different materials as soil covers on the agronomic performance of three lettuce cultivars. The experiment was arranged in randomized blocks, with treatments set in a subdivided plot scheme. Five types of soil cover (plots) were tested: no cover, black plastic, double white faced plastic, straw mulching and kraft paper and three Lettuce cultivars (subplots): loose-crested leaf group, iceberg lettuce group, with four replicates. Number of leaves per plant, stem length and diameter, head diameter, mass of fresh and total dry matter, fresh matter mass of leaves and stem were evaluated. For the Lisa and Americana lettuce groups, bed soil cover materials were more efficient when compared to the uncovered beds. For economic and environmental reasons, kraft paper is recommended as a bedding cover material for these cultivars. Variation in growth occurred between the lettuce cultivars, independently of the use of bedding cover. This
occurred in the sequence: loose leaf > iceberg lettuce> loose-crested leaf group.
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Siwek, Piotr, Renata Wojciechowska, Andrzej Libik, and Andrzej Kalisz. "The Effect of Different Kind of Polyethylene Film Used as a Low Tunnel Cover on Celery Yield and Stalk Quality." Vegetable Crops Research Bulletin 70, no. 1 (January 1, 2009): 91–100. http://dx.doi.org/10.2478/v10032-009-0009-8.
Full textAbstract:
The Effect of Different Kind of Polyethylene Film Used as a Low Tunnel Cover on Celery Yield and Stalk QualityEarlier experiments showed that celery could be grown under different plastic covers for spring and autumn harvest. The most significant for yield quantity and quality were light conditions. In conducted studies (2005-2007) the effect of three different covers for low tunnels: transparent, white and black film (made of original and recycled polyethylene) on the growth, yield and some quality factors of celery Tango stalks was estimated. Only small differences in the length of celery stalks grown under different films were observed. In the third year of experiment stalks grown under black film were around 1cm longer than all the others. Mean values of the yield indicate that transparent film used as a cover and the control treatment increased slightly the obtained yield but the differences did not exceed several percent. Plants grown in more favourable light conditions accumulated more dry matter as well as more soluble sugars in celery stalks. No such differences were observed under original and recycled films.
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Abdullah, Oday I., and Josef Schlattmann. "Contact Analysis of a Dry Friction Clutch System." ISRN Mechanical Engineering 2013 (August 25, 2013): 1–9. http://dx.doi.org/10.1155/2013/495918.
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The numerical simulation of the friction clutch system (pressure plate, clutch disc, and flywheel) during the full engagement period (assuming no slipping between contact surfaces) is carried out using finite element method. Two types of load condition considered affect on the clutch elements during the full engagement period are the contact pressure of diaphragm spring and the centrifugal force. The study of the pressure distribution between the contact surfaces and the factors affecting it is one of the fundamentals in the process of designing the friction clutch to obtain accurate estimation of the temperature distribution during the slipping period and the contact stresses during the full engagement period. The investigation covers the effect of the contact stiffness factor FKN on the pressure distribution between contact surfaces, stresses, and penetration. The penalty and augmented Lagrange algorithms have been used to obtain the pressure distribution between contact surfaces. ANSYS13 software has been used to perform the numerical calculation in this paper.
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Nelson, Wendy A., Brian A. Kahn, and B. Warren Roberts. "Screening Cover Crops for Use in Conservation Tillage Systems for Vegetables Following Spring Plowing." HortScience 26, no. 7 (July 1991): 860–62. http://dx.doi.org/10.21273/hortsci.26.7.860.
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Several prospective cover crops were sown into 1-m2 monoculture plots on 9 Mar. 1987 and 10 Mar. 1988 at Bixby, Okla., and on 14 Mar. 1988 at Lane, Okla., after sites were plowed and fitted. Densities and dry weights of cover crops and weeds were determined in late April or early May of both years. Plots also were evaluated for degree of kill by glyphosate in 1988. Fourteen cover crops were screened at Bixby in 1987. Kentucky bluegrass (Poa pratensis L.) and three fescues (Festuca rubra L., Festuca rubra L. var. commutata Gaud.-Beaup., and Festuca elatior L.) were eliminated from further consideration due to inadequate cover density and inability to suppress weeds. Screenings of the 10 remaining covers were conducted at both locations in 1988. Annual ryegrass (Lolium multiflorum L.) and three small grains [rye (Secale cereale L.), barley (Hordeum vulgare L.), and wheat (Triticum aestivum L.)] were the most promising cover crops with respect to cover density, competitiveness against weeds, and degree of kill by glyphosate. Crimson clover (Trifolium incarnatum L.) and hairy vetch (Vicia villosa Roth) were the most promising legumes, but they generally were less satisfactory than the grassy covers in all tested aspects. A single application of glyphosate was ineffective in killing hairy vetch at both locations. Chemical name used: N-(phosphonomethyl)glycine (glyphosate).
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Schmidt, Olaf. "Molecular Methods for the Characterization and Identification of the Dry Rot Fungus Serpula lacrymans." Holzforschung 54, no. 3 (April 13, 2000): 221–28. http://dx.doi.org/10.1515/hf.2000.038.
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Summary Novel methods developed for characterization and identification of wood-inhabiting fungi target molecules of the organisms such as proteins and nucleic acids and use mycelial interaction, mating, antibodies, electrophoretic protein patterns, oligonucleotide primers and DNA sequencing. The article reviews the respective work on the dry rot fungus Serpula lacrymans in the Hamburg institute and also covers the international literature.
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Kalisz, Andrzej, Agnieszka Sękara, Andrzej Jurkow, and Aneta Grabowska. "Effect of biodegradable nonwoven covers on yield and chemical composition of overwintering onion." Italus Hortus 27 (April 2020): 41–54. http://dx.doi.org/10.26353/j.itahort/2020.1.4154.
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Floating row covers are important pre-harvest factors for maximizing the yield of vegetable crops grown under open-field conditions. It is necessary to replace oil-based nonwoven covers with biodegradable ones that are environmentally friendly. The aim of this study was to investigate the effects of biodegradable nonwoven covers, made of aliphatic-aromatic copolyesters, with or without fatty acid dimers (SB20/13, SB21/13, and SB28/13), on yield and chemical composition of ‘Glacier’ and ‘Swift’ winter onions. In the first experiment, we observed a higher total marketable yield and higher harvest index for onions covered with SB21/13 (by 24% and 3%, respectively) when compared to the control (polypropylene nonwoven). The SB20/13 cover significantly decreased mean bulb weight by 15.3% than in control. Bulbs harvested from the plots covered with SB21/13 had lower dry weight by 3.2-3.7% and those covered with SB28/13 showed the lowest L-ascorbic acid content when compared to all other treatments (by 6.3-10.3%). The lowest total sugar content was found in control onion bulbs, but it was significantly different only from bulbs covered by SB20/13, which had more sugar by 10.6%. In the second experiment, plants covered with the SB28/13 had a 1 st grade yield of onions higher by 47% than that of the control. The highest mean bulb weight was obtained from plants covered with the SB21/13 nonwoven. Covering with nonwovens caused a decrease in dry weight (SB20/13 and SB21/13, by 1.3-1.7%, respectively) and L-ascorbic acid (all nonwovens, by 15.6% for SB21/13 up to 22% for SB20/13) in onion bulbs in comparison to the control. Since the tested biodegradable nonwovens covers did not cause any decrease in the yield of winter onions compared to polypropylene nonwovens, the former appear to be a suitable environmental-friendly solution for the open-field cultivation of this important vegetable crop.
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Yamamoto, Tatsuya, Kenichi Matsuoka, and Renji Naruse. "Observation of internal structures of snow covers with a ground-penetrating radar." Annals of Glaciology 38 (2004): 21–24. http://dx.doi.org/10.3189/172756404781814834.
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AbstractTo complement a technique to detect internal structures of seasonal snow covers and glacier firn with ground-penetrating radar (GPR), we carried out calibration experiments and an observation of winter snow cover (5.7m thick dry snow with numerous ice layers) with an 800 MHz GPR. In particular, we aimed to discriminate periodic noise, which is inherent in GPR, from radar echoes and to obtain a relationship between the observed reflection strength and the magnitude of density contrasts. Experiments were done in air to evaluate noise levels and receiver characteristics of this system. Based on these, we removed noise from radar echoes in the snow-cover observation. We recognized numerous marked echoes in a noise-free radargram. The depths of these echoes coincided roughly with those of large density contrasts observed in the snow pit. Thus, we argue that the echoes correspond to thin ice layers. Furthermore, the minimum density contrasts detected by this GPR are found to vary from about 100 to 250 kgm–3 at 1–6m depth in the seasonal snow cover.
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Ganachari, Vaibhav Sidraya, Uday Chate, Laxman Waghmode, Prashant Jadhav, and Satish Mullya. "Simulation and experimental investigation of tool wear rate in dry and near-dry EDM process." World Journal of Engineering 18, no. 5 (February 10, 2021): 701–9. http://dx.doi.org/10.1108/wje-07-2020-0322.
Full textAbstract:
Purpose Many engineering applications in this era require new age materials; however, some classic alloys like spring steel are still used in critical applications such as aerospace, defense and automobile. To machine spring steel material, there exist various difficulties such as rapid tool wear rate, the rough surface formation of a workpiece and higher power consumption. The purpose of this paper is to address these issues, various approaches in addition to electrical discharge machines (EDM) are used such as dry EDM (DEDM) and near dry EDM (NDEDM). Design/methodology/approach This study focuses on these two approaches and their comparative analysis with respect to tool wear during machining of spring steel material. For this study, current, gap voltage, cycle time and dielectric medium pressure are considered input variables. This study shows that the near dry EDM approach yields better results. Hence, the thermo-electrical model for this approach is developed using ANSYS workbench, which is further validated by comparing with experimental results. This thermo-electrical model covers spark radius variation and formation of temperature profile due to electric discharge. Transient thermal analysis is used to simulate the electric discharge machining. Findings It is observed from this study that discharge environment parameters such as debris concentration and fluid viscosity largely influences the dielectric fluid pressure value. Experimental results revealed that NDEDM yields better results in comparison with DEDM as it shows a 25% lesser tool wear rate in NDEDM. Originality/value The range of predicted results and the experimental results are in close agreement, authenticating the model.
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Kaiser, K., A. Barthelmes, S. Czakó Pap, A. Hilgers, W. Janke, P. Kühn, and M. Theuerkauf. "A Lateglacial palaeosol cover in the Altdarss area, southern Baltic Sea coast (northeast Germany): investigations on pedology, geochronology and botany." Netherlands Journal of Geosciences - Geologie en Mijnbouw 85, no. 3 (September 2006): 197–220. http://dx.doi.org/10.1017/s0016774600021478.
Full textAbstract:
AbstractA new site with Lateglacial palaeosols covered by 0.8 - 2.4 m thick aeolian sands is presented. The buried soils were subjected to multidisciplinary analyses (pedology, micromorphology, geochronology, dendrology, palynology, macrofossils). The buried soil cover comprises a catena from relatively dry (’Nano’-Podzol, Arenosol) via moist (Histic Gleysol, Gleysol) to wet conditions (Histosol). Dry soils are similar to the so-called Usselo soil, as described from sites in NW Europe and central Poland. The buried soil surface covers ca. 3.4 km2. Pollen analyses date this surface into the late Allerød. Due to a possible contamination by younger carbon, radiocarbon dates are too young. OSL dates indicate that the covering by aeolian sands most probably occurred during the Younger Dryas. Botanical analyses enables the reconstruction of a vegetation pattern typical for the late Allerød. Large wooden remains of pine and birch were recorded.
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Petroff, A., and L. Zhang. "Development and validation of a size-resolved particle dry deposition scheme for application in aerosol transport models." Geoscientific Model Development 3, no. 2 (December 23, 2010): 753–69. http://dx.doi.org/10.5194/gmd-3-753-2010.
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Abstract. A size-resolved particle dry deposition scheme is developed for inclusion in large-scale air quality and climate models where the size distribution and fate of atmospheric aerosols is of concern. The "resistance" structure is similar to what is proposed by Zhang et al. (2001), while a new "surface" deposition velocity (or surface resistance) is derived by simplification of a one-dimensional aerosol transport model (Petroff et al., 2008b, 2009). Compared to Zhang et al.'s model, the present model accounts for the leaf size, shape and area index as well as the height of the vegetation canopy. Consequently, it is more sensitive to the change of land covers, particularly in the accumulation mode (0.1–1 micron). A drift velocity is included to account for the phoretic effects related to temperature and humidity gradients close to liquid and solid water surfaces. An extended comparison of this model with experimental evidence is performed over typical land covers such as bare ground, grass, coniferous forest, liquid and solid water surfaces and highlights its adequate prediction. The predictions of the present model differ from Zhang et al.'s model in the fine mode, where the latter tends to over-estimate in a significant way the particle deposition, as measured by various investigators or predicted by the present model. The present development is thought to be useful to modellers of the atmospheric aerosol who need an adequate parameterization of aerosol dry removal to the earth surface, described here by 26 land covers. An open source code is available in Fortran90.
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Schnabel, S., J. Lozano-Parra, Á. Gómez-Gutiérrez, and A. Alfonso-Torreño. "Hydrological dynamics in a small catchment with silvopastoral land use in SW Spain." Cuadernos de Investigación Geográfica 44, no. 2 (June 29, 2018): 557. http://dx.doi.org/10.18172/cig.3378.
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Hydrological processes were investigated since the year 2000 in a semiarid rangeland with disperse cover of evergreen holm oaks. In this article results are presented on the spatial variation of rainfall in the catchment using a network of 6 raingauges. Results are also presented on soil water dynamics, which were studied under different vegetation covers and varying soil depths. Furthermore, the temporal variation of runoff generation in the basin outlet is reviewed, taking into account different timescales. The following results can be highlighted: Spatial variation of rainfall in the catchment at annual or monthly scale was low. However, large dispersion exists in the case of individual rainstorms, when the differences between the 6 raingauges varied strongly, both for daily values as well as maximum intensities. Events with high spatial variation are presumably related with small, localized storms, particularly those of high intensity and short duration, and those showing low variation are probably of frontal origin. Soil moisture presented seasonal patterns clearly dependent on factors such as rainfall or evapotranspirative demand. Spatial distribution of soil moisture was mainly affected by physiographic terrain characteristics and vegetation covers. Generally, in dry hydrological years, soil moisture was lower beneath than beyond the tree canopies, while the opposite was observed in wet years. Dry situations increase the intensity and duration of soil water deficits, enhance the evaporative demand and increment water storage capacity by covers. Channel flow in dehesas depends highly on the antecedent moisture conditions and particularly on the water content of the sediment-filled valley bottoms. If these areas become saturated, high amounts of runoff are produced during rainfall events. Under high intensity rainstorms Hortonian overland flow is rapidly generated on hillslopes producing a quick channel response. Interannual runoff variation is very high, the more frequent low rainfall years provoke very low total water flow, contrasting with less frequent years of above average rainfall, which are the ones producing high total runoff. It can be concluded that the hydrological dynamics in Mediterranean rangelands with a disperse tree cover are complex, both regarding soil water and catchment runoff, being highly variable in time. Future changes in land use or climate could affect notably the hydrological dynamics of the catchment, and hence similar upland basins. For example, a notable increase of tree cover would reduce water availability of pasture plants, particularly during dry years. A decrease of annual rainfall amounts and/or increased drought intensities, as a consequence of climate change, would enlarge periods of soil moisture deficit for pasture plants, as well as a reduction of runoff.
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Rodrigues, M. Ângelo, Isabel Q. Ferreira, Sara L. Freitas, Jaime M. Pires, and Margarida P. Arrobas. "Self-reseeding annual legumes for cover cropping in rainfed managed olive orchards." Spanish Journal of Agricultural Research 13, no. 2 (May 29, 2015): e0302. http://dx.doi.org/10.5424/sjar/2015132-6252.
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<span lang="EN-US">Given the environmental impact of nitrogen (N)-fertilizer manufacture and use, the sustainable management of agro-systems should be sought by growing N-fixing legumes. In this work, eleven self-reseeding annual legumes were grown in pure stands as mulching cover crops in a rainfed olive orchard managed without grazing animals. Dry matter yield, N content in above-ground biomass, groundcover percentage and persistence of the sown species were assessed during four growing seasons. All covers provided enough soil protection over the year, with living plants during the autumn/winter period and a mulch of dead residues during the summer. The legumes overcame a false break observed in the third year recovering the dominance of the covers in the fourth growing season. This means that the seed bank established in previous seasons ensured the persistence of the sown legume even when a gap in seed production occurred. The early-maturing cultivars produced less biomass and fixed less N (approx. 50 kg N/ha/yr present in the above-ground biomass) than the late-maturing ones, but would compete less for water since the growing cycle finished earlier in the spring. They seem best suited to being grown in dry farmed olive orchards with low N demand in drought prone regions.<br /></span>
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Ben-Salem, Nahed, Sara Álvarez, and Manuel López-Vicente. "Soil and Water Conservation in Rainfed Vineyards with Common Sainfoin and Spontaneous Vegetation under Different Ground Conditions." Water 10, no. 8 (August 9, 2018): 1058. http://dx.doi.org/10.3390/w10081058.
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Soil erosion seriously affects vineyards. In this study, the influence of two vegetation covers on topsoil moisture and the effect of different physiographic conditions on runoff and sediment yields were evaluated in a rainfed vineyard formed by four fields (NE Spain) during 15 months. One field had spontaneous vegetation in the inter-row areas, and three fields had a cover crop of common sainfoin. Moisture conditions were dry and stable in the vineyards’ rows, wet and very variable in the inter-row areas and wet and very stable in the corridors. Topsoil moisture in the areas with common sainfoin was much higher than in the rows (62–70%), whereas this difference was lower with spontaneous vegetation (40%). Two runoff and sediment traps (STs) were installed in two ephemeral gullies, and 26 time-integrated surveys (TIS) were done. The mean runoff yields were 9.8 and 13.5 L TIS−1 in ST2 and ST3. Rainfall depth (12 mm) and erosivity (5.2 MJ mm ha−1 h−1) thresholds for runoff initiation were assessed. The mean turbidity was 333 (ST2) and 19 (ST3) g L−1. Changes in the canopy covers (grapevines and vegetation covers), topography and rainfall parameters explained the runoff and sediment dynamics.
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Adamczewska-Sowińska, Katarzyna, Józef Sowiński, Mirosław Anioł, Piotr Ochodzki, and Roman Warzecha. "The Effect of Polyethylene Film and Polypropylene Non-Woven Fabric Cover on Cobs Parameters and Nutritional Value of Two Sweet Maize (Zea mays L. var. saccharata Bailey) Hybrids." Agronomy 11, no. 3 (March 12, 2021): 539. http://dx.doi.org/10.3390/agronomy11030539.
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In 2012–2014, at the Research and Didactic Station of the Department of Horticulture at Wroclaw University of Environmental and Life Sciences (51°19′06″ N, 17°03′49″ E), field studies were conducted to evaluate the responses of two sweet maize hybrids to sowing dates (early and optimum) and five methods of maize plant coverings—polyethylene film: perforated (PE), red (PER), green (PEG), polypropylene non-woven fabric (PP), and control (C), with non-irrigation systems. Total yield and morphological characteristics of cobs were compared. In 2012 soluble sugars and carotenoids content were measured. The use of maize cover at the beginning of growth (PE and PER) significantly influenced the number of rows, while PE and PEG increased the number of grains per cob. Covering maize sown at a later date, with polyethylene film and non-woven fabric, ensured better production effects than using such covers after earlier sowing. Signet F1 hybrid was charact0erized by significantly higher sugar content and Rustler F1 by higher lutein and zeaxanthin levels. The application of the optimum sowing date resulted in a significantly higher yield of cobs, by 11.3%, than after early sowing. The yield increase as a result of the applied covers was higher after sowing at a later date. The content of dry matter in grains was positively correlated with the content of sucrose, glucose, and fructose. The change in carotenoids content also depended on the accumulation of dry matter in the kernels. The study confirmed the correlation of sweet maize accumulated growing degree days (AGDD), and revealed dependence of grain quality on dry matter content in the grain.
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RUIZ, GUSTAVO R. S., and ROBERTA M. VALENTE. "The first schizomid from a dry forest in South America (Arachnida: Schizomida)." Zootaxa 4311, no. 1 (August 22, 2017): 81. http://dx.doi.org/10.11646/zootaxa.4311.1.5.
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Schizomids are arachnids typically found on the ground of areas with rainforest, living in the moist litter. Here we describe Surazomus algodoal sp. nov. from a coastal, dry environment on an island of the state of Pará, Brazil, in the Atlantic Ocean. Only one male has been collected, but the morphology of the flagellum is unique. Surazomus algodoal sp. nov. represents the first epigean schizomid living only in a dry forest and the easternmost record for Surazomus Reddell & Cokendolpher. The type of dry vegetation in which the animal was found covers only a small area and is endangered by human use. The new species is considered critically endangered using the IUCN criteria.
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Jabłońska-Ceglarek, R., and W. Wadas. "Effect of nonwoven polypropylene covers on early tuber yield of potato crops." Plant, Soil and Environment 51, No. 5 (November 19, 2011): 226–31. http://dx.doi.org/10.17221/3578-pse.
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In this six-year research study the effect of nonwoven polypropylene covering on the quantity and quality of early potato yield was estimated. The use of nonwoven polypropylene covers resulted in an increase in the tuber yield and smaller yield variability in the various years, when compared with the traditional cultivation, especially at a very early date of potato harvest. In the cultivation with nonwoven polypropylene covering, the marketable tuber yield 60 days after planting was higher by 23.34% on average and 75 days after planting by 10.92% in the six-year period of the study, compared with the cultivation with no plant covering. The higher profitable effect of covering was obtained in the years with cold spring. The cultivation method of the potato did not affect the chemical composition of the tubers harvested after 60 days from planting. After 75 days from planting the tubers of potato cultivated under nonwoven polypropylene covers contained, on average, more dry matter and starch by 0.81% and 0.85%, respectively.
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Ng, Charles W. W., Jian Liu, and Rui Chen. "Numerical Investigation on Gas Emission from Three Landfill Soil Covers under Dry Weather Conditions." Vadose Zone Journal 14, no. 8 (August 2015): vzj2014.12.0180. http://dx.doi.org/10.2136/vzj2014.12.0180.
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Raeini-Sarjaz, M., and N. N. Barthakur. "Water use efficiency and total dry matter production of bush bean under plastic covers." Agricultural and Forest Meteorology 87, no. 1 (November 1997): 75–84. http://dx.doi.org/10.1016/s0168-1923(97)00007-5.
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Jarquin-Enriquez, L., E. Mercado-Silva, and E. Castaño-Tostado. "EFFECT OF TWO GREENHOUSE COVERS ON GROWTH, DRY MATTER CONTENT AND TOMATO FRUIT QUALITY." Acta Horticulturae, no. 697 (December 2005): 481–86. http://dx.doi.org/10.17660/actahortic.2005.697.61.
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Ishizaka, Masaaki. "New categories for the climatic division of snowy areas in Japan." Annals of Glaciology 26 (1998): 131–37. http://dx.doi.org/10.3189/1998aog26-1-131-137.
Full textAbstract:
New categories for the climatic division of snowy areas according to their snow-cover character in mid-winter are proposed. They are a wet-snow region, a dry-snow region, an intermediate snow region and a depth-hoar region. The wet-snow region is defined as the region in which every layer of deposited snow is wet due to percolation of snowmelt water throughout the winter. In contrast, areas in which the snow cover is dry, at least in the coldest period of the winter season, are classified into two categories, that is the dry-snow region and the depth-hoar region. In the latter region, the small snow depth and low air temperature induce development of depth hoar. The intermediate snow region was introduced to indicate an intermediate character between the dry-snow and wet-snow regions. From the climatic dataset calculated by the Japanese Meteorological Agency and from snow surveys, it has been found that in snowy areas, which have a climatic monthly mean temperature in January (Tjan) higher than 0.3°C, snow would be expected to be wet throughout the winter and, in areas that have Tjan, lower than −1.1°C, to be dry at least in the coldest period. Snow covers, where Tjan is between these two values, are expected to have intermediate characters. Therefore, these temperatures are supposed to be critical values among the wet, dry and intermediate snow regions. The criterion that separates the depth-hoar region from the dry-snow areas was found to be given by a climatic mean temperature gradient. This value lies between 10 and 12°Cm−1, which is derived by dividing the absolute value of the average of the climatic monthly mean air temperature, which is always below 0°C, by the average of the monthly maximum snow depth during January and February.
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Ishizaka, Masaaki. "New categories for the climatic division of snowy areas in Japan." Annals of Glaciology 26 (1998): 131–37. http://dx.doi.org/10.1017/s0260305500014695.
Full textAbstract:
New categories for the climatic division of snowy areas according to their snow-cover character in mid-winter are proposed. They are a wet-snow region, a dry-snow region, an intermediate snow region and a depth-hoar region. The wet-snow region is defined as the region in which every layer of deposited snow is wet due to percolation of snowmelt water throughout the winter. In contrast, areas in which the snow cover is dry, at least in the coldest period of the winter season, are classified into two categories, that is the dry-snow region and the depth-hoar region. In the latter region, the small snow depth and low air temperature induce development of depth hoar. The intermediate snow region was introduced to indicate an intermediate character between the dry-snow and wet-snow regions. From the climatic dataset calculated by the Japanese Meteorological Agency and from snow surveys, it has been found that in snowy areas, which have a climatic monthly mean temperature in January (Tjan ) higher than 0.3°C, snow would be expected to be wet throughout the winter and, in areas that have Tjan, lower than −1.1°C, to be dry at least in the coldest period. Snow covers, where Tjan is between these two values, are expected to have intermediate characters. Therefore, these temperatures are supposed to be critical values among the wet, dry and intermediate snow regions. The criterion that separates the depth-hoar region from the dry-snow areas was found to be given by a climatic mean temperature gradient. This value lies between 10 and 12°Cm−1, which is derived by dividing the absolute value of the average of the climatic monthly mean air temperature, which is always below 0°C, by the average of the monthly maximum snow depth during January and February.
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Poluektova, Valentina A., and Nikolay I. Novosadov. "Dry Mortar with Redispersible Polymeric Powder for Additive Technologies." Materials Science Forum 974 (December 2019): 101–6. http://dx.doi.org/10.4028/www.scientific.net/msf.974.101.
Full textAbstract:
Special formulas of dry building mortars for construction concrete printing is one of the pertinent areas in the development of innovative construction. The research covers the dry building mortar technology with re-dispersible polymeric powders. The best regime of mixing components with a high-speed paddle wheel agitator was presented. It was shown that only the automation of the construction material production for 3D printing will provide the necessary level of composition stability and property optimization. The work presents some methods of technical control in the production environment. According to the devised functions the technical specifications for the material use were developed. The technical and operational characteristics of the obtained material were researched and the advantages of using polymer-cement concrete in construction 3D printing were identified. On the basis of the obtained results it was established that the specifically designed composition of the mortar reduces stiffening time, has good adhesion characteristics and the necessary plastic strength, this material also delivers impressive performance when it comes to strength and other technical and operational characteristics in comparison with the test mortar.
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Giancotti, Paulo Roberto Fidelis, Mariluce Pascoína Nepomuceno, Juliana de Souza Rodrigues, Micheli Yamauti, José Valcir Fidelis Martins, and Pedro Luís da Costa Aguiar Alves. "Residues of sweet sorghum promotes suppression of weeds in sugarcane rotation." April 2020, no. 14(04):2020 (April 20, 2020): 565–73. http://dx.doi.org/10.21475/ajcs.20.14.04.p1903.
Full textAbstract:
Sorghum is an important crop to plant in rotation with sugarcane. This is mainly because both are inputs for the ethanol industry. Crop residues of sweet sorghum promote suppression of weed re-infestation, avoiding weed interference to the sugarcane crop due to the strong allelopathic potential of sorghum. In order to determine the suppressive effects of sorghum crop residues on weeds, a field experiment was carried out. Seven vegetation covers were used as options for crop rotation with sugarcane. The treatments were sweet sorghum, velvet bean, sunflower, soybean, sugar cane, fallow, and an area without cover. The experiment was randomized blocks with four replications of 27 m2 plots. The weed community of each plot was evaluated by phytosociological indexes at 60 and 120 days after the formation of vegetation cover. The composition of soil seed bank was also evaluated. The weeds with the highest indexes of relative importance during the evaluations were Cyperus rotundus, Raphanus raphanistrum and Parthenium hysterophorus. The diversity of the weed community, estimated by relative importance indexes, was lower in the area with velvet bean as soil cover. Sorghum, velvet bean and sunn hemp covers reduced the soil seed bank compared to the fallow treatment and the treatment without vegetation cover. Crop residues of sweet sorghum and velvet bean provide a decrease in weed infestation in field, and the weed suppression period can last up to 120 days during the dry season.
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Bai, Tian, Audrey Mayer, William Shuster, and Guohang Tian. "The Hydrologic Role of Urban Green Space in Mitigating Flooding (Luohe, China)." Sustainability 10, no. 10 (October 9, 2018): 3584. http://dx.doi.org/10.3390/su10103584.
Full textAbstract:
Even if urban catchments are adequately drained by sewer infrastructures, flooding hotspots develop where ongoing development and poor coordination among utilities conspire with land use and land cover, drainage, and rainfall. We combined spatially explicit land use/land cover data from Luohe City (central China) with soil hydrology (as measured, green space hydraulic conductivity), topography, and observed chronic flooding to analyze the relationships between spatial patterns in pervious surface and flooding. When compared to spatial–structural metrics of land use/cover where flooding was commonly observed, we found that some areas expected to remain dry (given soil and elevation characteristics) still experienced localized flooding, indicating hotspots with overwhelmed sewer infrastructure and a lack of pervious surfaces to effectively infiltrate and drain rainfall. Next, we used curve numbers to represent the composite hydrology of different land use/covers within both chronic flooding and dry (non-flooding) circles of 750 m diameter, and local design storms to determine the anticipated average proportion of runoff. We found that dry circles were more permeable (curve number (mean ± std. error) = 74 ± 2, n = 25) than wetter, flooded circles (curve number = 87 ± 1). Given design storm forcing (20, 50, 100 years’ recurrence interval, and maximum anticipated storm depths), dry points would produce runoff of 26 to 35 percent rainfall, and wet points of 52 to 61 percent of applied rainfall. However, we estimate by simulation that runoff reduction benefits would decline once infiltration-excess (Hortonian) runoff mechanisms activate for storms with precipitation rates in excess of an average of 21 mm/h, contingent on antecedent moisture conditions. Our spatial metrics indicate that larger amounts and patches of dispersed green space mitigate flooding risk, while aggregating buildings (roofs) and green space into larger, separate areas exacerbates risk.