Cowpea (Vigna unguiculata) is a major source of dietary protein and essential component of the cropping systems in semi-arid regions of Sub-Saharan Africa. However, yields are very low due to lack of improved cultivars, poor management practices, and limited inputs use. The objectives of this study were to assess the effects of rhizobia inoculant and P on nodulation, N accumulation and yield of two cowpea cultivars in Mozambique. Field study was conducted in three contrasting environments during the 2013/2014 and 2014/2015 seasons using randomized complete block design with four replications and four treatments. Treatments consisted of seed inoculation, application of 40 kg P2O5 ha-1, inoculation + P, and a non-inoculated control. The most probable number (MPN) technique was used to estimate the indigenous bradyrhizobia populations at the experimental sites. The rhizobia numbers at the sites varied from 5.27 × 102 to 1.07 × 103 cells g-1 soil. Inoculation increased nodule number by 34–76% and doubled nodule dry weight (78 to 160 mg plant-1). P application improved nodulation and interacted positively with the inoculant. Inoculation, P, and inoculant + P increased shoot dry weight, and shoot and grain N content across locations but increases in number of pods plant-1, seeds pod-1, and 100-seed weight were not consistent among treatments across locations. Shoot N content was consistently high for the inoculated plants and also for the inoculated + P fertilized plants, whereas the non-inoculated control plants had the lowest tissue N content. P uptake in shoot ranged from 1.72 to 3.77 g kg-1 and was higher for plants that received P fertilizer alone. Inoculation and P either alone or in combination consistently increased cowpea grain yield across locations with yields ranging from 1097 kg ha-1 for the non-inoculated control to 1674 kg ha-1 for the inoculant + P treatment. Grain protein concentration followed a similar trend as grain yield and ranged from 223 to 252 g kg-1 but a negative correlation between grain yield and protein concentration was observed. Inoculation increased net returns by $104–163 ha-1 over that for the control. The results demonstrate the potential of improving cowpea grain yield, quality and profitability using inoculant, although the cost-benefit for using P at the current fertilizer price is not attractive except when applied together with inoculant at low P site.

Inoculation with effective Bradyrhizobium spp., and phosphorus application enhance atmospheric nitrogen fixation in soybean production. Soybean form symbiotic associations with the right rhizobium strain to incorporate atmospheric nitrogen into the plant tissues. The objective of this study was to evaluate responses of two soybean varieties to inoculation, phosphorus and starter-nitrogen, and their interactions on nodulation, growth, yield components and grain yield in different agroecologies of Mozambique. The study was conducted at three locations in Nampula, Tete and Zambézia provinces in Mozambique during 2012 and 2013 seasons. Two soybean genotypes (Storm and TGx 1904-6F) in split-plot design with phosphorus (P 2 O 5 ) rates as main plot, inoculation application as subplots and nitrogen rates as sub-sub plots with four replications were used. Nodulation, plant growth, biomass nutrient content at R3 stage, yield and yield components were evaluated. Data analyzed for combined and individual locations in Statistical Analysis System ® 9.4 indicated that inoculation increased nodulation and yield (37% to 95%) in both soybean genotypes but the effect of phosphorus on nodule formation was not consistent across sites and varieties. Inoculants have a potential to supply required nitrogen for soybean production in Mozambique because farmers seldom use mineral fertilizers due to its high cost.

Soybean production in sub-Saharan Africa is increasing as farmers open more land areas for cultivation and replace other crops, such as tobacco, in favor of this legume crop. Despite the production is increased in Mozambique, demand for animal feed and oil is not satisfied. As such, farmers explore ways to improve yield per unit area of soybean by using bio-inoculants from various sources and agroecological adaptability. These bio-inoculants are seldom available during planting time, and retail at almost similar prices although yield varied based on the product source, handling, and the rhizobia strain carrier. Mozambique does not produce bio-inoculants, so it obtains the product from neighboring countries or as far as the South American continent. In this study, we evaluated the performance, ecological adaptability, and soybean productivity of seven Bradyrhizobium diazoefficiens strain-based bio-inoculants from several countries with different carrier materials: Biofix, Masterfix, Nitrofix, NitroZam, N-Fixer, Soygro Peat, and Soygro Liquid against a control (non-inoculated) on two soybean varieties Storm and TGx 1904-6F. The trial was conducted in the 2016 and 2017 growing seasons in three agroecologies of Mozambique at Angonia, Nampula, and Ruace. Data on nodulation, plant growth, biomass nitrogen content at beginning of podding (R3) stage, yield, and yield components of soybean were evaluated. Analysis of variance and contrast comparisons were performed on the Statistical Analysis System® 9.4. Nodule weight per plant variedly increased from 7.7 to 167.6 mg with inoculation of both varieties across environments. Plant tissue nitrogen content at the R3 stage was higher in inoculated non-promiscuous variety at 3.9% than the promiscuous counterpart with 3.7%. Storm, a non-promiscuous short-maturity variety of soybean, responded to inoculation and accumulated more N than the medium-to-late maturity promiscuous TGx 1904-6F. Higher N tissue content is an indicator of better nutritive value, as well as high-quality recyclable biomass of inoculated soybean. Both Storm and TGx 1904-6F responded to all inoculants variedly with NitroZam yield of 2,750 kg ha−1 being highest, while Soygro Liquid was lowest with 2,051 kg ha−1 but more than the check with 1,690 kg ha−1 across sites. There were varietal differences in 100-seed weight after inoculation where Storm (15.4 g) had heavier seeds than TGx 1904-6F (13.1 g). The results show that inoculation improved plant growth and development, increased nodulation, and gave higher yields for better economic returns among farmers. Inoculation has the potential of increasing soybean yield, nutritive value, and biomass quality within Mozambique.

Soybean yield within the Southern Africa falls below its potential despite similar climatic conditions across some agroecologies, replicable agronomic management practices and introduced improved varieties. Understanding physiological processes and water-use efficiency (WUE) of soybean offer information on bridging this yield gap. A field study was conducted in 2017 and 2018 seasons in two agroecologies (Angonia and Ruace) in Mozambique to evaluate the effects of Bradyrhizobium diazoefficiens strain USDA110 formerly known as Bradyrhizobium japonicum inoculant, nitrogen and phosphorus on nodulation, physiology and yield of non-promiscuous (Safari) and promiscuous (TGx 1740-2F) soybean varieties. Data on transpiration, photosynthesis, leaf area index, radiation interception and WUE from the beginning of flowering to maturity were collected. Transpiration rate varied considerably with interaction between locations, growth stages, varieties and treatments. At podding, phosphorus-treated soybean at Angonia transpired less (6.3 mmol/m2/s) than check plants (6.6 mmol/m2/s). Photosynthesis rate and WUE were distinct with variety, growth stages and inputs within agroecologies. For instance, in Angonia 2018 season, phosphorus fertilized TGx 1740-2F photosynthesized more at flowering (25.3 μmol/m2/s) while the lowest was phosphorus-treated Safari at podding with 17.2 μmol/m2/s. At the same site in 2017, inoculated soybean photosynthesized more at 22.8 μmol/m2/s leading to better WUE of 3.6 that corresponded to 2894 kg/ha yield. Overall, soybean WUE was higher when inoculated than N-treated, while P application yielded better. Results from this study will complement breeders’ effort in developing phosphorus efficient varieties suited for a wide range of changing climatical conditions.

Standard poultry manure use recommendations in North Carolina consider waste analysis but not differences among manure types, cropping seasons, or application timing. This study evaluated poultry manure source, N rate strategy, and application time effects on soft red winter wheat (Triticum aestivum L.) tiller density, yield components, grain yield, and N availability coefficients. Coefficients included fertilizer N equivalence based on grain yield and plant‐available N based on aboveground plant N content. Four field experiments used broiler litter (BL) and composted layer manure (CLM), two rates (67 and 134 kg total‐N ha−1), and three different application times (incorporated in October preplant, Feekes’ 3 in December/January, or Feekes’ 4 in February). Dual‐source treatments received 67 kg N ha−1 of manure plus 67 kg N ha−1 as urea ammonium nitrate (UAN) solution at Feekes’ 5. Fertilizer‐N (UAN) rate treatments (0, 39, 78, 117, and 156 kg N ha−1) were also included. Yields responded to N inputs but were lowest when BL and CLM were applied at 67 kg N ha−1 either preplant or at Feekes’ 3. Grain yield and N availability were greater with CLM than with BL (3.0 vs. 2.8 t ha−1 grain and 58 vs. 52 kg ha−1 N uptake, respectively). Availability coefficients ranged from 12 to 32%, lower than the standard assumed values of 50 to 60%. The feasible poultry manure application window includes preplant until Feekes’ 4, but fertilizing winter wheat crops solely with poultry manure may supply less N than intended.