A four-year continuous cropping cycle with a very low P addition resulted in a negative P balance (deficit) for all crop rotation treatments at all four locations (Table 9). The greater soil P deficit in forage legume crop rotation treatments (alfalfa-alfalfa-wheat-canola and red clover-red clover-wheat-canola) compared to annual legume (barley-pea-wheat canola) and non-legume crop rotations (barley-flax-wheat-canola) was due to the significantly greater P removal through enhanced biomass production by crops in rotation. During the first two years of crop rotations, (especially the second year), forage legumes produced significantly greater biomass relative to annual crops (data not shown). Also, wheat and canola following forage legume produced significantly higher biomass during the last two years of the crop rotations. In this study, soil P fertility was depleted every year by the crop biomass harvest. Without adequate P replenish- ment through fertilizer addition or manuring, especially in the forage legume rotations where P removal is higher, it is anticipated that P limitations will eventually arise. Therefore, it is critical to apply sufficient P to match the crop P removal over time in order to preserve the soil P fertility over the long-term.
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The experimental animals from the herds in Basawa were fed lablab (Lablab purpureus) forage as the supplement. Lablab is a forage legume recommended for the Nigerian savanna. It is a fast growing plant with high foliage and seed production potential, and is capable of maintaining its nutritive value far into the dry season (up to February) . The lablab forage was grown and processed on-station at NAPRI. Each animal was fed 3 kg of lablab forage/day after milking in the morning before going out for grazing. The supplementation lasted for only 45 days beginning from the first day of milking since the feed produced could only last for this time period.
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ture of forage legume species is expected to gen- erate new knowledge towards achieving higher and more stable biomass and N yields. In addition, integration of sward containing forage legumes only in grassland is expected to increase the sup- ply of protein without N fertilization. Thus, we conducted this study with the objectives of deter- mining how the swards of forage legume species will affect: herbage yield, botanical composition, N yield and the percentage and amount of N derived from the atmosphere. The following hypotheses were tested: functional complementarity between the species with different above-and below-ground architecture increases 1) the herbage yield and N accumulation, and 2) the proportion of legume-N derived from the atmosphere in the forage legume mixtures compared to pure stands .
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The use of legumes is an alternative to decrease erosion and restore and maintain soil fertility of Brazilian pas- tures. The benefits of inclusion of legumes in pastures are unquestionable. Unfortunately, however, such proce- dure is rarely adopted in livestock production system. Moreover, in Brazil, there are just a few studies aiming at developing technology for legume seed dispersion by introducing seeds in the diet of cattle, goats, sheep and/or horses [1-3]. On the other hand, many studies using the collection of manure from cattle grazing reported that many plant species are able to survive passage through the digestive tract of ruminants [4,5]. Until now, however, Ecology and Animal Science handle the dispersal of leg-
Organic grain system managers have to find solutions to nitrogen deficiency and weed infestation. It is especially true when no animals are present on the farm to justify the use of forage legumes despite their interests in the crop succession. Our study focused on the role of four legume cover crop species inserted in a succession of winter wheat and maize on both problems. This insertion consisted in relay- intercropping the legumes under the canopy of wheat. Cover crops were maintained on the field after the harvest of the cereal until the sowing of the subsequent maize crop. The performance of the three crops of the succession was monitored as well as weed development and nitrogen dynamic in the soil- plant system. On the one hand, our results showed that black medic and red clover, that supported the best the competition of wheat, were likely to decrease its grain protein content at harvest (-0.3 to - 0.4 %). On the other hand, the four species did not decrease intercropped wheat grain yield. They were able to control weed infestation during the intercropping period and between the two cash crops. Finally, nitrogen restitution to the subsequent maize crop was efficient and allowed a significant 30 % increase of maize grain yield.
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Like the rest of African countries, farming systems in many communal areas of South Africa is small scale, mixed crop-livestock systems. Livestock system is composed of cattle, goat and sheep. These livestock require good quality pastures to maintain satisfactory animal performance throughout the year. However, achieving and maintaining the satisfactory animal performance is a major challenge in summer rainfall areas like the Eastern Cape Province due to the shortage of fodder and poor quality of natural grasses during the winter or dry season. Therefore, legume production to supplement the natural pastures with protein should form part of the animal production or farming systems in the Eastern Cape province of South Africa. Forage legumes also present a cheaper feed supplement than commercial concentrates and can be grown by smallholder farmers (Njarui and Wandera ). To evaluate the potential of these legumes, better knowledge is required on how to include the legumes into existing farming systems. The aim of the study was to determine the effect of forage legume inclusion on the dry matter yield (DMY) production and quality of pastures in four seasons in the semi-arid Lushington communal area in the Eastern Cape Province, South Africa.
The genes involved in R-body production were originally identiﬁed in Caedibacter taeniospiralis (5) and include rebA, rebB, rebC, and rebD (5, 6). Moreover, genes that are homologous to rebA, rebB, and rebD of C. taeniospiralis have been found in species of the phylum Proteobacteria and in Kordia algicida OT-1 (7), which belongs to the phylum Bacteroidetes, whereas no rebC-homologous genes have been identiﬁed in bacteria other than C. taeniospiralis (8, 9). It is hypothesized that reb-homologous genes were passed on by horizontal gene transfer—i.e., by phages or plasmids (2, 8, 10, 11). Although many bacterial species that carry reb-homologous genes are pathogenic to plants and animals (e.g., Xanthomonas axonopodis pv. citri, Stenotrophomonas malto- philia, Burkholderia pseudomallei, and so on) (8), the rhizobium Azorhizobium caulino- dans ORS571, a mutualistic microsymbiont of the tropical legume Sesbania rostrata, possesses reb-homologous genes (8, 12). To date, reb-homologous genes have not been found in rhizobia other than A. caulinodans ORS571.
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The extensive breeding system is the most adopted in Brazil, the pastures when well managed, are the lowest cost food for cattle production, a variable that has the greatest economic impact on production systems, since diet and food management are the most onerous factors in this activity (01). According to Santos et al. (2017), tropical forages provide low-cost energy substrates, mainly fibrous carbohydrates. However, climatic in clemencies and seasonality limit the cattle production system into pasture, especially during the dry season of the year. During this period, low rates of animal production are observed, due to the low availability of pasture accompanied by poor quality of the forage material, since at this period occurred changes in the composition of the pasture, such as an increase in stem size, a greater lignification of the cell walls, reduction of leaf: stem ratio, elevation of dead matter, among others, able to decrease the digestibility of the forage consumed by the animals. Detmann et al. (2014) showed the importance of ensuring the availability of forage mass during the dry period of the year, since it is considered a latent energy bank. In this way, researchers use techniques to
A critical examination of data (Table and Figure 1, 2 and 3) reveals that legume mixture had significant effect on number of tillers/m 2 , green fodder, dry fodder yield, protein content and protein yields over oat at first and second cutting in pooled analysis. The pooled data for the two years show that oat : berseem (2:1) recorded significantly higher number of tillers/m 2 , green fodder, dry fodder yield, protein content and protein yields amounting to increases of 16.71 and 20.35 and 22.76 and 22.99 and 22.87; 17.87, 21.00 and 19.38; 110.58 and 12.30; 29.95 and 35.60 percent, respectively over sole oat sown. Legume mixture oat + berseem (2:1) was closely followed by oat + lucerne (2:1) in pooled analysis and significantly improved the above said parameters over sole oat, respectively. The observed improvement in various characters might be owing to beneficial effect of legumes on cereal as legume fixes nitrogen in the soil through the process of biological nitrogen fixation, which is utilized by the oat and its role in tillering is well established. These findings was corroborating with the findings of Choubey and Prasad (2001).
Among various factors influencing microbial metabolism in the rumen, liquid turnover rate and forage to concentrate ratio have been found to alter the balance of microbial species and consequently impact their fermentation pathways. Ruminal output or flow to the omasum divided by ruminal volume gives the fractional passage rate. For liquid, this is often called “dilution rate”. Slow growing microorganisms, especially certain protozoa, would wash out of the rumen if the dilution rate exceeded their growth rate (Carro et al., 1995). In addition, Hoover et al. (1984) suggested that high dilution rates result in energetic uncoupling with diminished protein digestion and microbial growth. In contrast, if the dilution rate is reduced, accumulated metabolites may adversely affect microorganisms (Fuchigami et al., 1989). Variation in the forage to concentrate ratio is one of the most commonly modified characteristics of practical ruminant diets. With medium to high forage diets, rates of fermentation are normal and avoid the accumulation of fermentation end-products to
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The use of nitrogen application to encourage grass growth in legume grass mixtures has negative effects on the nitrogen fixed by the accompanied legume. A decrease in nitrogen fixed by the Rhizobium can be expected with minimal rates of applied nitrogen. McAuliffe et al.  found that the percent of fixed nitrogen in 10-week old alfalfa plants decreased from 58% to 17% with the addition of 22 - 89 kg N ha −1 . However, most producers do not have the ability or not find it economically sound to fertilize with nitrogen rates less than 56 kg∙ha −1 . The main reason for alfalfa inclusion into bermudagrass is its ability to fix nitrogen from the air. It is only logical to decide a threshold for the mixture composition and forage yield to which economical nitrogen rates can again be applied for grass production. This may be simply done using the potential yield and forage value of bermuda- grass receiving 112 kg N ha −1 compared to the alfalfa bermudagrass mixture receiving 0 kg N ha −1 . The rela- tively predictable linear regressions equation for yield and forage quality compared to alfalfa composition was utilized to develop an economic threshold. In well managed improved bermudagrass pastures in Mississippi re- ceiving 112 kg N ha −1 in split applications, DM yield, ADF, NDF, and CP were 1699 kg∙ha −1 , 36%, 64%, and 10% respectively . Using these paremeters and the predictive equations from Figure 1, DM yield would be matched when alfalfa composed only 60% of the mixture. In addition, mixtures containing less than 20% alfalfa could still produce lower NDF values and greater CP values than well managed bermudagrass. Bermudagrass alone will have similar ADF values grass/legume mixed systems with less than 40% alfalfa. Considering that forage nutritive value must be compromised with forage yield, the data suggest that after the second harvest of the third year alfalfa composition, yield and forage nutritive value have all decreased enough to justify a shift in management for ideal bermudagrass management.
In contrast with O. cumana in which races have been identified and the new ones are continuously evolving defeating newly introduced resistance genes (Fernández-Martínez et al. 2008), there is no clear evidence for the existence of races of O. crenata. This might be due to the lack of a selection pressure as there is little resistance in commercial cultivars of most legume hosts (Rubiales et al. 2006). However, O. crenata populations are known to be very het- erogeneous (Román et al. 2001, 2002a) and the risk exists that they can be selected for virulence when challenged by the widespread use of highly resistant cultivars. In fact, a virulent population has already been selected by the frequent culture of the resistant vetch cultivar in Israel (Joel 2000).
The closely related tribes Desmodieae, Phaseoleae and Psoraleae are also mainly of tropical/sub-tropical distribution, and with rare exceptions, species within these tribes showed a desmodioid nodule structure [2,15]. Rhizobia have been characterized for 25 species from three genera, Desmodium, Kummerowia and Lespedeza, in the Desmodieae (Table 4). Species from all three genera, Desmodium microphyllum, Desmodium racemosum, Desmodium sequax, Kummerowia striata, Lespedeza bicolor and Lespedeza daurica, were nodulated by rhizobia from three separate genera. Similarly, for 28 species across 14 genera within the Phaseoleae, there was no strong evidence for high specificity for rhizobial symbiont (Table 4). Phaseolus vulgaris and Vigna unguiculata have been highlighted as being promiscuous with respect to their rhizobial symbionts under field conditions. Data in Table 4 show that both species can be nodulated by different rhizobial genera in the α-proteobacteria, as well as Burkholderia in the β-proteobacteria. Across three studies, Phaseolus lunatus was reported to be nodulated by Bradyrhizobium and Rhizobium, while Vigna angularis, Vigna radiata and Vigna subterranea were reported to be nodulated by three separate rhizobial genera. Data are limited for other genera/species within the Phaseoleae with the exception of Glycine max, which is the main grain/oil seed legume grown worldwide, and Glycine soja. Both Glycine spp. were nodulated by Bradyrhizobium, Ensifer and Rhizobium. In the one case where separate studies were carried out on one species within the Psoraleae, Psoralea pinnata was nodulated by Bradyrhizobium, Burkholderia and Mesorhizobium [136,193,287]. Thus, where tested, species within the Desmodieae, Phaseoleae and Psoraleae were promiscuous with respect to their rhizobial symbionts.
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Rhizobia have been characterized from 15 species across seven genera in the tribe Ingeae and ca 90 species from 13 genera in the tribe Mimoseae within the sub-family Mimosoideae (Table 1). Bradyrhizobium, Ensifer, Mesorhizobium and Rhizobium were each reported to nodulate species in the Ingeae and the Mimoseae. Also, Ochrobactrum was reported to nodulate Acacia mangium (Ingeae), Allorhizobium and Devosia were reported to nodulate Neptunia natans (Mimoseae), and there are many reports that Cupriavidus and Burkholderia nodulate Mimosa spp. and related species (Mimoseae) (Table 1). In addition, with the exception of Acacia auriculiformis (Ingeae) and Mimosa diplotricha (Mimoseae), all species which were examined in three or more separate studies, Acacia mangium, Acacia saligna, Calliandra grandiflora and Senegalia senegal (Ingeae), Leucaena leucocephala, Mimosa pudica, Parapiptadenia rigida, Prosopis alba and Vachellia tortilis (Mimoseae), were nodulated by at least three different rhizobial genera. Thus, a range of rhizobial genera, including both alpha- and beta-proteobacteria, can nodulate legume species across the two Mimosoideae tribes and, generally, where tested over different studies, species within the Ingeae and Mimoseae tribes were promiscuous with respect to their rhizobial symbionts.
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The Hillgrove trial was originally planted in 1983 to explore the climatic and edaphic adaptaion of new legume species. Only very scant details of the trial exists today including; the location, soil type and that there was a focus on Stylosanthes hamata (80 accessions) and Desmanthus spp (30 accessions). Other species included: Alysicarpus sp, Arachis sp, S.scabra, Centrosema molle, C.pascuorum, Macroptilium and Vigna spp. In all 150 accessions were trialed (Burt 1986).
Root nodules are highly organized root organs where the nitrogen fixation take place in, its formation are the results of complicated interactions between legumes and rhizobia. The nodule formation and nitrogen fixation are energy-demanding processes. During nodule formation and nitrogen fixation ， a large amount of sucrose, as the major end product of photosynthesis is required to be transported into nodules. In legume root nodules, hydrolysis of sucrose by Sucrose synthase (SuSy) is a necessary prerequisite for normal nodule development and a key step in nitrogen fixation. Deficient SuSy activity in nodules renders them incapable of effective nitrogen fixation. ENOD40 play a role in the regulation of sucrose utilization in nodules through the soyabean ENOD40 peptides directly binding to SuSy.In both legumes and non-legumes, ENOD40 expression is important in nodule organogenesis and development. However, during symbiotic development, whether Nod factor signaling associate with in the regulation of sucrose utilization in nodules is unknown. NORK the immediately downstream component of these Nod factor receptors, is central to the Nod factor signalling cascade. NORK functions not only in the early signaling pathway operative in root hairs, but also in later stages of nodule formation. In this study, we found that the GmENOD40expression level decreased in GmNORKRNAisoybean transgenic root by rhizobial inoculation. Thus provide important detail information toward understanding the functions of NORK and GmENOD in symbiotic signaling and nodule development.
There was a significant difference in the percent- age of adults which emerged in the legume seeds studied. Seeds of cowpea and garden pea had the highest percentage adult emergence followed by pigeon pea, bambara nut, chickpea and green gram. The lowest percentage adult emergence was observed in common bean seeds. Although slightly higher mean counts of eggs were laid on common bean than on black gram and soya bean, a smaller percentage of adults emerged from com- mon bean. Seifelnasr (1991) observed a similar trend in haricot bean where a total of 41 eggs were deposited which was higher than the number deposited on chickpea (26) or on bambara nut (39) but none of the larvae survived to adulthood. Microscopic examinations revealed that the newly hatched larvae had died before boring the seed coats or cotyledons of haricot bean.
Among the plant growth form, herbs constituted 48%, and it was followed by shrub (22%), tree (20%) and climbers (10%). Although possession of tendril is a common feature in papilionoid genera, the ability to climb has been taken as criteria to mention a climber. Several genera like Acacia, Lathyrus, Phaseolus, Cassia, Crotalaria etc. were found to possess three or more species (Table 1). About 87% of alien legumes are invasive in nature of which 8 species were primarily categorized as ‘very high’ invasive and 6 species are primarily designated as ‘highly’ invasive’. Twelve species were categorized as ‘moderate’ and 9 species showed ‘low’ invasiveness. Five species are not invasive in nature although they were alien in study areas (Table 1). Among the most invasive species, Leucaena and Cassia exhibited tremendous capacity to grow along roadside as well as deep inside the study areas. Cultivated fields and banks of water bodies were preferred by 20% and 10% species, respectively. Quadrat studies revealed high frequency of some of the legumes like Leucaena leucocephala, Cassia sophera, C. tora, C. occidentalis, Crotalaria pallida, Melilotus alba and Phaseolus in study sites (Table 1). The ratio of number of plants (cumulative of 400 quadrats/year) between cultivated field and roadside varied between 0.53-0.88, but it was close to 1.0 for Cassia sophera (0.98), and >1.0 for Leucaena leucocephala. Documentation of spread of alien flora cumulative of 2800 total quadrats laid over the last seven years (2005-2011) revealed steep rise in number of certain legume species such as species of Cassia, Crotalaria, Leucaena, Melilotus, Desmodium, and Phaseolus (Fig. 2). Low to moderate rise was documented for other species. Some of these species particularly Leucaena reportedly possesses allelopathic potential, which has been postulated as one of the potent weapons for rapid introduction and seedling establishments of invasive legumes even in rough, polluted and nutrient- deficient terrain throughout the world (Lee, 2002).
mixcropping resulted in increased water and nutrient uptake and thus, it conserved the soil (Vasilakoglou et al., 2005). Vetch with cereals, facilitates the forage growth and improve forage quality whereas cereals in return provide advantages as, structural support, better light interpretation and harvesting (Thompson et al., 1992). However, insufficient and limited investigation on cereal-legume mixtures for forage yield and quality has been carried out in subtropical dry regions, Pothwar of Pakistan.
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(harvest three), and Lynx (harvest four). The highest lignin pea at each harvest timing was: PS10300121W (harvest one), Granger (harvest two), Melrose (harvest three), and Melrose (harvest four). At the first harvest timing, crimson clover and hairy vetch were predicted to release more N than any pea genotype (Figure 5). The pea genotype with the highest N concentration consistently was predicted to release less N than crimson clover, hairy vetch, and the high biomass producing pea (Figure 5). A pea genotype that produces substantial N while maintaining high N concentration is desirable. Biomass and protein were generally significantly correlated, and there was a very slight decline in N concentration as biomass increased (data not shown). This relationship was not strong enough to prevent researchers from trying to target increasing biomass and N concentration simultaneously. By the second, third, and forth harvest timings, the high biomass producing pea was predicted to release N at the same rate as hairy vetch, and crimson clover was releasing less N (Figure 5). These results demonstrate that some pea genotypes can be competitive with hairy vetch and crimson clover for releasing N to the subsequent cash crop; a critical component of the success of a legume cover crop.
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