Letteratura scientifica selezionata sul tema "Legume; wheat; phosphorus"

A considerable portion of the phosphorus (P) fertilisers applied in agriculture remains in the soil as sorbed P in the forms of various P compounds, termed residual P. Certain grain legume crops may be able to mobilise residual P through root exudates, and thus increase their own growth, and potentially that of subsequent cereal crops. The first objective of this pot experiment was to compare the growth and P uptake of 3 legume crop species with that of wheat grown in a soil with different levels of residual P. Another objective was to determine whether the influence of legumes on subsequent P uptake by wheat was due to legume-induced changes in the rhizosphere, or to the presence of legume roots. White lupin (Lupinus albus L.), field pea (Pisum sativum L.), faba bean (Vicia faba L.), and wheat (Triticum aestivum L.) were grown in a soil containing 25.7, 26.4, 30.8, 39.0, or 51.9 mg/kg of bicarbonate-extractable P and sufficient amounts of nitrogen to suppress nodulation and dinitrogen fixation. Differences among the species in root dry mass were much larger than those in shoot dry mass. Faba bean produced the greatest root dry mass. All the legumes exuded carboxylates from their roots, predominantly malate, at all soil P levels. Rhizosphere concentrations of carboxylates were highest for white lupin, followed by field pea and faba bean. All of the investigated legumes enhanced the growth of the subsequently grown wheat, compared with wheat grown after wheat, even at relatively high levels of soil P. The positive effect on growth was not dependent on the incorporation of the legume roots into the soil. The legumes also caused a modest increase in wheat shoot P concentrations, which were higher when roots were incorporated into the soil. Because of the increased growth and tissue P concentrations, wheat shoot P content was 30–50% higher when grown after legumes than when grown after wheat. The study concludes that the legume crops can enhance P uptake of subsequently grown wheat, even at relatively high levels of residual P.

SUMMARYTrials were conducted in 1987 and 1988 to test methods of intercropping annual Ethiopian clovers, Trifolium spp, with wheat. Several different clover varieties, sowing methods, plant spacings, planting dates and rates of phosphorus application were compared. Planting in single or double alternative rows 20 cm apart did not affect wheat grain and straw yield but broadcast sowing of Trifolium in wheat rows 20 cm apart reduced wheat yield. The Trifolium species used significantly affected legume yield. Phosphorus fertilizer increased yield significantly, especially that of the legume component. The trials indicated that the intercropping of Ethiopian clovers in wheat has potential under African highland conditions.Siembra simultanea de trigo/ Trifolium en Etiopía

The purpose of this paper was to show the economic rationale behind growing legume plants in crop rotation. To pursue that objective, this paper presents a modified profitability accounting method for agricultural production which takes biological benefits into consideration. The following sequence of crop rotation was used in this study: forage pea – winter rape – winter wheat. An assumption was made that, from an economic point of view, the after-effect of legume crops on soil and yields of subsequent crops is an important factor which, however, is disregarded in calculations. Research suggests that legume crop growing brings measurable benefits in following years. As regards forage pea, rape and wheat, biological benefits represented 2%, 19% and 12% of total income, respectively, in the study period. Feedback from respondents suggests that 25% of the interviewees do not reduce nitrogen fertilization input in the years after growing legume crops. In turn, as much as 83% of farmers surveyed do not reduce their phosphorus and potassium fertilization rates for subsequent crops. However, agricultural producers usually fail to take account of additional biological benefits brought about by legumes when assessing their economic competitiveness against cereals and rape.

AbstractSustainability of cereal-based cropping systems remains crucial for food security in South Asia. However, productivity of cereal–cereal rotations has declined in the long run, demonstrating the need for a sustainable alternative. Base crop, that is, common crop in different crop rotations, productivity could be used as a sustainability indicator for the assessment of different long-term crop rotations. This study aimed to evaluate the impact of grain legume inclusion in lowland rice–wheat (R-W) and upland maize–wheat (M-W) rotation on system’s base crop (rice in lowland and wheat in upland crop rotations) productivity and sustainability and also in soil fertility. Mung bean (April–May) inclusion in R-W rotation increased rice grain yield by 10–14%. In upland, mung bean inclusion in M-W rotation increased wheat grain yield by 5–11%. Replacing wheat with chickpea in R-W rotation increased rice grain yield by 5–8%. Increased base crop productivity in legume inclusive rotations was attributed to significant improvement in panicle (rice) or spike (wheat) attributes. Increased soil organic carbon and available nitrogen and phosphorus in the legume inclusive rotations significantly influenced the base crop productivity in both the production systems. Among the crop rotations, R-W-Mb (in lowland) and M-W-Mb (in upland) rotations had the highest system productivity and net return. Therefore, intensification/diversification of cereal–cereal rotations with grain legume could improve soil fertility and sustain crop productivity.

The effect of 2 tillage practices (zero v. conventional), fertiliser application (nitrogen, phosphorus and zinc), and pulse–cereal rotation on changes in soil mineral nitrogen, plant-available water in the soil, grain yield and protein, and key soil fertility parameters (total nitrogen, organic carbon) in the Central Highlands of Queensland were examined between 1991 and 1998. Four pasture treatments (perennial legume, perennial grass, annual legume and legume–grass mixes) were included in January 1995, following previously unsuccessful attempts to grow lucerne and annual medics. The experiment was conducted as an opportunity cropping system on an open downs soil at Gindie that is representative of a large proportion (70%) of soils in the Central Highlands. Tillage practice did not affect the amount of mineral nitrate or the plant-available water content of the soil at planting, except in 1991 and 1998 when plant-available water content was higher under conventional tillage than zero tillage. However, zero tillage improved grain yield in 2 of 4 years (wheat in 1992; sorghum in 1996), increased uptake of nitrogen in every crop and produced greater grain protein levels in both wheat crops grown than conventional tillage. There were grain responses to nitrogen + phosphorus fertilisers (wheat in 1991 and sorghum in 1997). Grain protein was increased with applications of nitrogen regardless of whether phosphorus was added in 3 of the 4 crops planted. Sowing a pulse did not significantly increase grain yields in the following crop although it did increase soil mineral nitrogen at planting. Soil nitrate remained low in control (P0N0) plots (<39 kg N/ha) when crops were planted each year but increased significantly (average 84 kg N/ha) following a long fallow of 3.5 years resulting from drought. Plant-available water content of the soil at sowing was lower where chickpeas had been grown the previous season than with wheat. Neither tillage practice nor fertiliser application affected soil organic carbon or soil total nitrogen concentrations in the topsoil. However, all pasture treatments improved soil total nitrogen compared with continuous cropping, and with the exception of annual pasture legumes, also improved soil organic carbon after only 2 seasons. Largest improvements in soil fertility (total nitrogen and organic carbon) occurred with perennial species. It was concluded that zero tillage practices can have beneficial impacts on grain yields as well as minimising environmental degradation such as soil erosion in this region. However, if soil fertility levels are to be maintained, or improved, perennial pasture rotations will need to be used as current levels of fertiliser application or rotations with pulses had no significant beneficial effect.

The dynamics of soil P forms and particle size fractions was studied under three wheat-based cropping sequences in production systems of Argentina. The whole soil and its coarse (100–2000 µm) and fine (0–100 µm) fractions were analyzed to determine Bray-Kurtz extractable (Pe), organic (Po), inorganic (Pi), and total (Pte) phosphorus. The reference soil was determined at time 0 and compared to a four-year period (time 9 to 12) in three crop sequences: wheat (Triticum aestivumL.)-cattle grazing on natural grasses (WG), continuous wheat (WW), and wheat-legume (WL). Levels of Pe showed differences over time, from 10 to 16 µg g−1in WG, in line with agriculture and cattle grazing alternate sequences. In WW, P level increased with time, while in WL systems a significant decrease in P from 33.7 to 10.4 µg P g−1was found during the legume period. Soil P values varied between reference soil and soil samples in year nine and between treatments. Pi was significantly lower in WW, and its concentration increased with time. The coarse fraction of the reference plots had significantly higher levels of Po and Pi than the cultivated treatments, probably a consequence of the particulate organic matter decomposition and coarse mineral particle weathering. The observed changes in Pi content could be attributed to differences in occluded P equilibrium under different soil environments (mainly pH) and crop-tillage-climatic interaction.

The present study set out to test the hypothesis through field and simulation studies that the incorporation of short-term summer legumes, particularly annual legume lablab (Lablab purpureus cv. Highworth), in a fallow–wheat cropping system will improve the overall economic and environmental benefits in south-west Queensland. Replicated, large plot experiments were established at five commercial properties by using their machineries, and two smaller plot experiments were established at two intensively researched sites (Roma and St George). A detailed study on various other biennial and perennial summer forage legumes in rotation with wheat and influenced by phosphorus (P) supply (10 and 40 kg P/ha) was also carried out at the two research sites. The other legumes were lucerne (Medicago sativa), butterfly pea (Clitoria ternatea) and burgundy bean (Macroptilium bracteatum). After legumes, spring wheat (Triticum aestivum) was sown into the legume stubble. The annual lablab produced the highest forage yield, whereas germination, establishment and production of other biennial and perennial legumes were poor, particularly in the red soil at St George. At the commercial sites, only lablab–wheat rotations were experimented, with an increased supply of P in subsurface soil (20 kg P/ha). The lablab grown at the commercial sites yielded between 3 and 6 t/ha forage yield over 2–3 month periods, whereas the following wheat crop with no applied fertiliser yielded between 0.5 to 2.5 t/ha. The wheat following lablab yielded 30% less, on average, than the wheat in a fallow plot, and the profitability of wheat following lablab was slightly higher than that of the wheat following fallow because of greater costs associated with fallow management. The profitability of the lablab–wheat phase was determined after accounting for the input costs and additional costs associated with the management of fallow and in-crop herbicide applications for a fallow–wheat system. The economic and environmental benefits of forage lablab and wheat cropping were also assessed through simulations over a long-term climatic pattern by using economic (PreCAPS) and biophysical (Agricultural Production Systems Simulation, APSIM) decision support models. Analysis of the long-term rainfall pattern (70% in summer and 30% in winter) and simulation studies indicated that ~50% time a wheat crop would not be planted or would fail to produce a profitable crop (grain yield less than 1 t/ha) because of less and unreliable rainfall in winter. Whereas forage lablab in summer would produce a profitable crop, with a forage yield of more than 3 t/ha, ~90% times. Only 14 wheat crops (of 26 growing seasons, i.e. 54%) were profitable, compared with 22 forage lablab (of 25 seasons, i.e. 90%). An opportunistic double-cropping of lablab in summer and wheat in winter is also viable and profitable in 50% of the years. Simulation studies also indicated that an opportunistic lablab–wheat cropping can reduce the potential runoff + drainage by more than 40% in the Roma region, leading to improved economic and environmental benefits.

Legumes are important constituents of Bangladeshi diet and provide a considerable portion of dietary proteins, minerals, and vitamins. The ready to eat soup powder prepared from legume and vegetables in the laboratory can provide an improved nutritional status. Incorporating processed rice, corn, and processed wheat flour as the starch source, three different samples of soup powder were prepared. Protein source was derived from legumes and vegetable paste was used as a mineral source. All these three developed formulations have a protein value ranging from 19.00 to 19.40% and calorie content 347 to 353 Kcal/100g (Table 2). Sensory evaluation of the products revealed a reasonable acceptance of the sample prepared from wheat flour. The selected soup powder contains 19.40 percent protein and 350 Kcal of energy per 100g. Commercially available soup powder was compared with all samples in the light of its nutritional values. Protein and energy content of the selected sample is comparable with the commercial one, which contain only 7.77 percent protein and 297 Kcal energy per 100 g. Prepared soup powder is also a good source of carbohydrate and minerals, mainly iron, calcium & phosphorus. Storage study was conducted to determine the shelf life of the developed food product. Statistical analysis shows that there is no significant difference during the storage of the selected soup powder for six months DOI: http://dx.doi.org/10.3329/bjar.v32i3.547Bangladesh J. Agril. Res. 32(3) : 451-459, September 2007

Phosphorus (P) deficiency is a common constraint to crop growth in many parts of the world. For optimum plant growth, P is often added to soil as inorganic fertiliser or as crop residues. It has been shown that addition of legume residues can increase P availability by supplying P within the residues but also by mobilising native soil P which could reduce the dependence on inorganic P fertilization for crop growth. In soil, P is found in various organic and inorganic pools which vary in availability. The size of these pools is affected by soil properties such as pH; the flux among these pools determines the relative size of pools and also influences P availability. Less is known about how soil properties such as texture and organic matter content affect the size of the various P pools and if this is modulated by addition of residues or inorganic P fertilisers. The aims of this study were to (i) assess the changes in the P pools over time as affected by residue P concentration and plant part (root or shoot) (ii) to compare the effect of different rates of P added as inorganic P or as residues on soil P pools and growth and P uptake by wheat, (iii) assess short and longer term changes in P pools in soils with different physical and chemical properties amended with residues differing in P concentration. The research conducted involved laboratory experiments as well as glasshouse experiment. In these experiments three South Australian soils with low P availability and a wide range of legume residues were used. The soils were selected to represent different physical and chemical properties that may affect P availability and were collected from Mount Bold (Mt. Bold) (acidic sandy clay loam), Monarto (neutral loamy sand), and Langhorne Creek (alkaline sandy loam). To have a wide range of P concentrations, the following root and shoot residues from field or glasshouse-grown plants differed in C, N, P content, maturity were used: mature white lupin (Lupinus albus L., low P concentration), mature chick pea (Cicer arietinum L., medium P concentration) and young faba bean (Vicia faba L., high P concentration). To investigate the changes in P pools during legume residue decomposition legume shoot or root residues with varying P concentrations of faba bean, chickpea and white lupin (high P, medium P and low P) were added to a loamy sand soil at a rate of 20 g residue kg⁻¹ soil and the concentration of various P pools were assessed on day 0 and after 14, 28 and 56 days of incubation. The result of this experiment showed that the size of the P pools changed over time and was affected by both residue P concentration and plant part. The differences in soil P pools among residues were greatest in the first 14 days. Later there was an increase in stable organic and inorganic P in the residue amended soils, indicating net conversion of labile into stable P. Differences in P pools between roots and shoots occurred mainly in the initial phase. The concentration of NaOH-Po increased from d0 to d14 with root and shoot residues, but then decreased from d14 to d28 with addition of shoot residues whereas the concentration of this pool increased when root residues were added. The changes over time were generally more pronounced in low-P than in medium-P residues. In the second experiment, the short term effects (42 days) of different rates of P added either as inorganic P or as legume residues on soil P pools and wheat growth were compared. In this glass house experiment wheat was grown to the flowering stage (42 days) in a loamy sand soil from Monarto amended with shoot residues of faba bean (high P) chickpea (medium P) and white lupin (low P) at a rate of 5 or 15 g residue kg⁻¹ soil. Inorganic P was added at four different rates (3, 10, 30 and 100 mg P kg⁻¹) corresponding to the total P added with the different residues at the two residue rates. Soil P pools were determined at wheat harvest. Compared to inorganic P addition, P added with residues led to a 10-80% greater increase in shoot biomass at the two highest P addition rates. In residue P amended soil, resin P and microbial P were correlated with wheat P uptake whereas in soil amended with inorganic P, resin P and NaOH Pi pools mainly contributed to P uptake.. Over time, the concentration of HCl P decreased in the residue treatments and that of residual P decreased in all treatments suggesting that these so-called non-labile P pools are quite dynamic and could serve as P source for plants. To assess the impact of soil properties on changes in P pools induced by legume residue addition, three legume different residues differing in P concentration: faba bean (high P) chickpea (medium P) and white lupin (low P), were added at a rate of 20 g kg⁻¹ to three soils differing in pH, organic C content and texture from Monarto (pH 7.5), Mount Bold (pH 5.1) and Langhorne Creek (pH 8.1) and incubated for 42 days. In residue-amended soils from day 0 to day 42, the concentration of water soluble and microbial P decreased, whereas the concentrations of NaHCO₃ Pi and NaOH Po increased; the magnitude of these changes differed among soils, being greatest in the Mt Bold soil. Residue addition had little or no effect on the concentrations of NaOH Pi, HCl Pi and residual P which also did not change significantly over time. Principal component analysis (PCA) of the data showed that most effects of residue addition to soils on microbial activity and growth and soil P pools can be generalized across the three soil used in this study, but that the size of the P pools is affected by soil properties such as organic carbon content, pH and texture. To assess longer term temporal changes in P pools in two soils with contrasting physical and chemical properties amended with residues differing in P concentrations, another incubation experiment was carried out with Monarto and Mt Bold soil amended with shoot residues of faba bean (high P) chickpea (medium P) and white lupin (low P). The concentration of the P pools was measured on days 0, 14, 28, 56, 70 and 98. The PCA plot based on the soil P pools showed a clear separation between the un-amended control soils and those amended with white lupin residues on the one hand and soils amended with faba bean and chickpea residues on the other. The concentrations of most P pools and particularly the labile P pools on days 28 and 56 were higher in soil amended with faba bean and chickpea residues than in the un-amended soil and that with white lupin residues. Despite some differences in temporal changes in P pools between Monarto and Mt. Bold, the PCA showed that the P pool concentrations on day 0 and 98 were quite similar and differed from the P pool concentrations on days 28, 56 and 70 suggesting clear temporal patterns and a limited effect of residue addition on P pool concentrations in the long term. Nevertheless, the temporal changes were more pronounced in the soils amended with faba bean and chickpea residues suggesting that addition of residues with medium or high P concentration has a greater effect on the dynamics among the soil P pools than residues with low P concentration. At the start and the end of the experiment, the concentrations of microbial P and NaOH-Pi were high in both soils, but the concentration of HCl-P was high only in the alkaline Monarto soil whereas the Mt Bold soil was characterized by high resin P concentrations.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2013

In phosphorus (P) deficient soils, several legumes have been shown to mobilise less labile P pools and to have a greater capacity to take up P than cereals. In conditions where N was not limiting, some legumes can increase the growth and P uptake of the following cereals which may be related to P mobilisation by the legumes. There is little information about the size of various soil P pools in the rhizosphere of legumes in soil fertilised with P although P fertiliser is often added to legumes to improve N₂ fixation. The aims of this study were to (i) compare the growth, P uptake and the concentration of rhizosphere soil P pools of different grain legumes, (ii) compare the decomposition rate of grain legume and wheat residues, and (iii) determine the effect of legume pre-crops and residue addition on growth, P uptake and concentrations of rhizosphere P pools of the following wheat. A series of plant growth experiments were carried out in a glasshouse to compare the growth of the different grain legumes and wheat and the concentrations of P pools of the rhizosphere soil. The soil pH determines the dominant P forms, therefore, two soils which were low in available P and contrasting pH (a loamy sand soil pH 8.8 and a sandy loam pH 5.4) were used in separate experiments to which soluble P was added to ensure good plant growth. Additionally, another experiment was conducted in the alkaline soil with lower P supply. Nodulated chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), white lupin (Lupinus albus L.), yellow lupin (Lupinus luteus L.) narrow-leafed lupin (Lupinus angustifolius L.) and wheat were grown until maturity. Plant dry weight and P uptake were measured, sequential P fractionation was employed to determine the concentrations of P pools in the rhizosphere of the legumes and wheat. Irrespective of soil pH and P supply, growth and P uptake were greatest in faba bean whereas the less labile P pools were most strongly depleted in the rhizosphere of white lupin despite its lower growth and P uptake compared to faba bean. In the alkaline soil with high P supply, compared to the unplanted control soil, the depletion of labile pools (resin P and NaHCO₃) were greater in the rhizosphere of faba bean whereas in the alkaline soil with low P supply and the acidic soil, white lupin depleted most of the labile pools more strongly than the other legumes. An incubation study was carried out to compare the decomposition rate and the available N and P concentrations after addition of the legume and wheat residues. Shoots, roots and the combination of shoots and roots of wheat, faba bean, chickpea and white lupin were mixed into the loamy sand soil. The decomposition rate was measured over 42 days by determining soil CO₂ release and the concentrations of available P and N in the soil were measured on days 0 and 42. Chickpea shoot residue decomposed faster than the other residues. Compared to the control soil without residue addition, resin P concentration was increased with legume residue addition but not with wheat residue addition. Inorganic N was increased significantly with addition of faba bean and white lupin residues compared to the un-amended control whereas wheat residue addition had no effect. In order to differentiate between the effect of the legume pre-crop alone and that of legume pre-crop and their residue on the following wheat, soil grown with legumes from which rootand shoot residues were removed or added back were planted with wheat. Growth, P uptake and concentrations of rhizosphere P pools of the following wheat were measured. Generally, growth was greater in wheat grown in the previously unplanted soil than in the pre-cropped soils. Among the pre-crops, in the alkaline and acidic soils with high P supply, the growth of the following wheat was greater in legume pre-crop soil without residue than with residue addition. The reverse was true for plant P concentration in the alkaline soil whereas in the acidic soil, plant P concentration was similar among the treatments. Varying results with residue addition on the growth of following wheat were observed in the alkaline soil with low P supply, but residue addition consistently increased wheat P concentration. In the loamy sand (pH 8.8) with high P supply, regardless of the pre-crops, wheat depleted the less labile residual P, NaOH-Pi and particularly NaOH-Po, whereas in the sandy loam (pH 5.4), the depletion was greatest in resin P. Similarly, in the loamy sand soil with low P supply, wheat after legumes depleted labile and less labile pools more than wheat after wheat. Generally, the addition of pre-crop residues increased the size of organic P pools in the rhizosphere of wheat grown in pre-crop soils. The results of this study showed that in the alkaline loamy sand, among the legumes only those with the greatest depletion of either labile or less labile pools (faba bean at high P and white lupin at low P supply) enhanced the growth of the following wheat. At high P supply, the pre-crop faba bean with greatest depletion of labile pools resulted in a greater depletion of less labile pools by the following wheat than the other legumes. At low P supply, the pre-crop white lupin with greatest depletion of labile and less labile pools induced a greater depletion of the less labile pools in the rhizosphere of wheat. On the other hand, in the acidic sandy loam, the legumes with the greatest depletion of most pools (labile and less labile) did not increase the growth of the following wheat compared to legumes with little depletion. Furthermore, the addition of legume pre-crop residues increased the concentration of organic P pools in the rhizosphere of the following wheat compared to pre-crop alone but generally decreased wheat growth.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture Food and Wine, 2012

A number of studies have shown that biomass and P uptake in cereals following legumes are higher than in cereals following cereals. The positive effect of legumes on the following wheat may be due to the growth of legumes prior to wheat and/or due to nutrients released during decomposition of legume residue that are used by the subsequent wheat. The aim of this study is to assess the effects of legumes and/or their residues on AM colonisation, P uptake and the growth of the following wheat. A series of short experiments were carried out to assess the relationship between P addition, P availability, P uptake and AM colonisation of wheat in a soil with low P availability under conditions in which N was not limiting. Young and mature faba bean shoots (FYS, FMS) and mature chickpea shoots (CP) were added to the soil at different rates. Other treatments included addition of inorganic P at different rates. As expected, inorganic P addition increased growth and P uptake, but decreased AM colonisation. AM colonisation was not correlated with available P in the soil amended with residues, whereas there was significant negative correlation between available P and AM colonisation within the treatments with inorganic P. FMS and CP addition not only decreased wheat growth and P uptake but also AM colonisation despite low P availability in the soil. It is concluded that addition of some legume residues cannot be explained solely by soil P availability. The aim of the first experiment with legume pre-crops was to identify the effect of legumes as a pre-crop and their residues on AM colonisation and P uptake by the following wheat. Four pre-crops (chickpea, faba bean, white lupin and wheat) were grown for 10 weeks in the loamy sand. Before planting wheat as the following crop, several treatments were imposed: (1) both roots and shoots of the pre-crop were removed completely; (2) only roots (0.04 % w/w) were added back into the soil to determine; (3) only shoot residues(0.24% w/w) mixed with soil; (4) a mixture of shoot and root residues (0.24% shoots + 0.04 % w/w roots) was added. Wheat growth and P uptake were greatest in the previously unplanted soil. Among the legume pre-crops, only white lupin increased the growth and P uptake but decreased AM colonisation of the following wheat compared with wheat as a pre-crop. The aim of last study was to investigate the effect of legume pre-crop and soil water content during the fallow period on P uptake and AM colonisation by the following wheat. The experimental design was similar as in the study described above but there was fallow period of one month. During the fallow there were two treatments: (1) soil moisture was maintained at 70% water-holding capacity, and (2) allowed to dry and maintained dry until wheat sowing and rewet to 70% water-holding capacity. Dry weight was generally similar with previous study while N and P concentrations of faba bean and white lupin were higher in this study. If compared with previous experiment without fallow time, this experiment showed a surprising results for N concentrations were about 50% lower in constant moisture treatment, while in drying-rewetting treatment resulted similar value with previous experiment.
Thesis (M.Ag.Sc.) -- University of Adelaide, School of Agriculture, Food and Wine, 2011

Faba bean is an important pulse crop in terms of protein source, area coverage, and volume of annual production in Ethiopia. The aim of this paper is to assess the agronomic and crop physiology investigations in the past two decades in Ethiopia. The production limiting factors of this crop are low input usage, natural disasters, depletion of macronutrients, and unavailability of essential nutrients. Phosphorus is among the main limiting nutrients in soil systems in Ethiopia. Seed yield and biomass yield of faba bean were increased from 1338 to 1974 kg/ha and from 3124 to 4446 kg/ha when phosphorous was changed from 0 to 52 kg/ha, respectively at Holeta whereas application of 40 kg P ha − 1 resulted in higher grain yield (6323 kg ha−1) and 3303 kg ha−1 at Lemu-Bilbilo and Bore highlands, respectively. The highest grain yield of 32 kg ha−1 was obtained from the application of 92 kg P2O5 ha−1 at Sekela district while application of 46 kg P2O5 ha−1 resulted in a substantial increase in seed yield over unfertilized plots on vertisols of Ambo. On the other hand, the results suggest that using starter nitrogen from 0 to 27 kg/ha has marginally increased faba bean yield but, a farther increase of nitrogen has indicated deteriorate of yield at Arsi zone. Proper plant populations play a crucial role in enhancing faba bean production. Planting faba bean at 30 cm × 15 cm spacing gave the highest grain yield in Duna district while it was 30 × 7.5 cm at vertisols of Ambo University research farm. Significantly higher seed yield (4222 kg/ha) was observed in the 40 cm inter-row spacing as compared to 50 cm inter-row spacing, which gave the lowest seed yield per hectare (3138 kg/ha) on fluvisols of Haramaya University. Intercropping and crop rotation are cropping systems that can increase soil fertility and crop yield. Intercropping of faba bean with barley at Debre Birhan increased land equivalent ratio than both crops when planted as sole. An additional income of 18.5% and 40% was gained than planting sole faba bean and wheat, respectively at Kulumsa. Faba bean can fix about 69 kg/ha nitrogen in Northern Ethiopia. Generally, the current review results showed that only limited studies in organic and bio fertilizer, plant density, and cropping systems were done on faba bean in Ethiopia. Hence, studies regarding soil acidity, organic fertilizer, and secondary plus micronutrient impacts on faba bean production and productivity along soil types and weather conditions need great attention in the future in Ethiopia.

Research was carried out at the Lithuanian Research Centre for Agriculture and Forestry’s (LAMMC) Joniškėlis Experimental Station on a clay loam Endocalcari Endohypogleyic Cambisol. The study was aimed to explore the aboveground mass of perennial forage legumes: red clover (Trifolium pratense L.) and lucerne (Medicago sativa L.), and their mixtures with festulolium (x Festuliolium), used as green manure, qualitative parameters and compatibility with cereals on the basis of nutrients nitrogen (N), phosphorus (P) and potassium (K). The deficiency of other nutrients (P, K) and intensity of green manure mineralization can lead to N absorption. It has been determined that winter wheat takes one kg of N together with 0.2 kg P and 0.6 kg K. Spring wheat requires a similar amount of P but a higher amount of K. Average winter wheat grain yield can be 4.0 t ha-1 on a clay loam Cambisol in organic cropping system. NPK content – 134 kg ha-1 is needed for such productivity (grain + straw). This content is lower for spring winter growing. P:N and K:N ratios are more favourable in perennial forage legume mixture with festulolium, as compared to legume alone. To obtain grain yields of 4 t ha-1 of winter wheat and 3 t ha-1 of spring wheat in balanced organic crop rotation it is sufficient to apply 3.0 and 2.0 t ha-1 DM of pure legume mass as green manure. “Cut-and-carry” fertilisers do not satisfy the wheat demand for P.

Vesicular-arbuscular mycorrhizal (VAM) fungi and other beneficial rhizosphere microorganisms, such as Rhizobium bacteria, must locate and infect a host plant before either symbiont profits. Although benefits of the VAM association for increased phosphorous uptake have been widely documented, attempts to improve the fungus and to produce agronomically useful amounts of inoculum have failed due to a lack of in vitro production methods. This project was designed to extend our prior observation that the alfalfa flavonoid quercetin promoted spore germination and hyphal growth of VAM fungi in the absence of a host plant. On the Israeli side of the project, a detailed examination of changes in flavonoids and flavonoid-biosynthetic enzymes during the early stages of VAM development in alfalfa found that VAM fungi elicited and then suppressed transcription of a plant gene coding for chalcone isomerase, which normally is associated with pathogenic infections. US workers collaborated in the identification of flavonoid compounds that appeared during VAM development. On the US side, an in vitro system for testing the effects of plant compounds on fungal spore germination and hyphal growth was developed for use, and intensive analyses of natural products released from alfalfa seedlings grown in the presence and absence of microorganisms were conducted. Two betaines, trigonelline and stachydrine, were identified as being released from alfalfa seeds in much higher concentrations than flavonoids, and these compounds functioned as transcriptional signals to another alfalfa microsymbiont, Rhizobium meliloti. However, these betaines had no effect on VAM spore germination or hyphal growth i vitro. Experiments showed that symbiotic bacteria elicited exudation of the isoflavonoids medicarpin and coumestrol from legume roots, but neither compound promoted growth or germination of VAM fungi in vitro. Attempts to look directly in alfalfa rhizosphere soil for microbiologically active plant products measured a gradient of nod-gene-inducing activity in R. meliloti, but no novel compounds were identified for testing in the VAM fungal system in vitro. Israeli field experiments on agricultural applications of VAM were very successful and developed methods for using VAM to overcome stunting in peanuts and garlic grown in Israel. In addition, deleterious effects of soil solarization on growth of onion, carrot and wheat were linked to effects on VAM fungi. A collaborative combination of basic and applied approaches toward enhancing the agronomic benefits of VAM asociations produced new knowledge on symbiotic biology and successful methods for using VAM inocula under field conditions