Abstract
AbstractSoybean 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.
Highlights
IntroductionYield continue to fall below the varieties production potentials due to climate change regardless of continuous expansion of cultivated land areas, introduction of improved varieties and use of plant nutrients inputs for soybean production (Khojely et al, 2018)
Temperature was comparable between the sites but declined towards the end of the seasons in Angonia creating favourable conditions for soybean rust (Fig. 1)
Inputs that avail more N to plants such as inoculants and organic fertilizers lead to increased photosynthesis increased water-use efficiency (WUE). This indicates that use of inoculant, timely application of N and P fertilizers in soybean production provide important elements necessary for photosynthesis, better WUE could translate into improved soybean yield in Mozambique and the larger southern Africa region. Yield of both promiscuous and non-promiscuous soybean varieties in Mozambique can be improved by use of inoculants and application of supplemental P fertilizer
Summary
Yield continue to fall below the varieties production potentials due to climate change regardless of continuous expansion of cultivated land areas, introduction of improved varieties and use of plant nutrients inputs for soybean production (Khojely et al, 2018). Cropping-seasons have been characterized by frequent events of irregular rainfall and drought both mid- and/or end-season (Ngcamu and Chari, 2020) that warrants better water-use efficiency (WUE) for yield improvement. Technologies for combating irregular rainfall patterns and drought are numerous, chief being water harnessing in reservoirs (during heavy rains) and irrigation. Smallholder farmers in sub-Saharan Africa (SSA) rarely adopt these due to a plethora of challenges. Instead, they rely heavily on rainfed production of crops. Other agronomic technologies such as: adjusting or changing planting dates, crop varieties, plant density, nutrient and soil moisture management practices can suffice to improve yield
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
