A total of 36 root‑nodule bacteria were isolated from southern Ethiopia using the Red Wolaita common bean variety, and 26 were authenticated as rhizobia and then screened for symbiotic effectiveness in a greenhouse at Arba Minch University. Among the authentic isolates, strains AMU23, AMU74, and AMU3A had symbiotic effectiveness values of 138%, 117%, and 116.7%, respectively, and were further evaluated along with a commercial strain, HB429, in farmers’ fields at varying altitudes with the Red Wolaita common bean variety. The selected rhizobial isolates were introduced by seed inoculation with coal‑based formulations prepared under controlled laboratory conditions, along with a commercial reference inoculant. In the field trial, the native strain AMU23 showed the highest nodule number (138.3), nitrogen derived from the atmosphere (84%), and grain yield (2.24 tons ha⁻¹), with superior production‑induced traits and larger effects at the lower altitude (Arguba site, 1160 m.a.s.l.). On the other hand, the strain AMU74 had the highest performance at the higher altitude (Tegecha site, 2174 m.a.s.l.), suggesting that native strains’ symbiotic efficiency and yield improvement were influenced by altitude. However, their effectiveness was also influenced by soil fertility parameters and environmental factors. In comparison, the commercial strain exhibited significantly lower grain yield and symbiotic performance (p < 0.05) than the native strains at both locations, yet it still improved productivity, indicating the superior efficacy of the locally sourced strains over the commercial inoculant. A multi‑locus sequence analysis (MLSA) clustered the native strains within the Rhizobium etli–Rhizobium phaseoli species complex, including Rhizobium etli CFN42 and Rhizobium phaseoli VMW4, whereas the commercial strain HB429 clusters tightly with the Rhizobium etli strain HBR51.
Tag: beans
Coping with drought: strategies to improve genetic adaptation of common bean in drought-prone regions of Africa
Common bean is enjoying resurgence in interes! and an enhanced level of consumption as a majar souree of protein for Afriean households owing to an outrageous inerease in priee of animal products. It also serves as a break erop in Maize-hased and rice-based systems to reduce decline in soil fertility. However, frequent drougbt and diseases Iimit roductivity of beans in Ihe region. It is partly because bean production in recent years has c”panded into semi-arid regions, due to an inerease in population pressure. While drought IS yet one of the most limiting faetors to bean production on a global scale, tbe situation wi II expectedly deteriorate in Afríe!! if the curren! trend of land degradation cannot be reversed. In addition, climatie variability will increase as it bas been postulated in a scenario of global warming.
Legume integration in smallholder farming systems for food security and resilience to climate change
A random sample of 847 households (HHs) in southern Ethiopia was used to assess the impact of HH characteristics, land and livestock ownership, seasonal variations, and agricultural challenges on cereals and legumes, crucial to community livelihoods. A structured survey was integrated into the ODK data collection tool, validated, and used with trained agricultural agents, and analyzed using an R statistical package. Farm productivity was significantly influenced by gender, since male headed HHs produced 25.5% more yield than female headed HHs. Livestock ownership, land cultivation, farm productivity and product utilizations were also varied among the HHs. Furthermore, agricultural practices like labor utilization, fertilizer and composite application, and use of improved seed varieties significantly affected the farm productivity. Besides, maize was identified as the principal and top-priority crop, while common bean (legume) was the second-priority crop for local people. This shows that legumes were important in the region’s agricultural systems, but some farmers experienced reduced productivity due to poor agronomic practices. Consequently, a substantial proportion of farmers (>50%) faced food shortages from February to June, representing the peak of the dry season and the beginning of the rainy season (April to May). Integrating early-maturing legumes in the farming system would help to escape the food shortage periods. Many farmers disclosed that the cost of chemical fertilizers’ was unaffordable, indicating a need for options like use of rhizobia inoculants and showed interest to use on their farms for improved productivities.
Assessing the agroforestry potential of selected native tree species in Rwanda
The deliberate integration of trees into crop and livestock farming systems has garnered significant attention for its ability to deliver environmental, economic, and social benefits. In Rwanda, this agroforestry approach is increasingly embraced because of its capacity to conserve the soil, produce food, feed, and wood products, and provide other essential ecosystem services. However, the limited integration and undervaluation of indigenous tree species in Rwandan farming practices reveal a critical gap in the sustainability of this practice. This study evaluated the agroforestry potential of nine native tree species by examining their compatibility with beans and maize, and their growth outside forest environments. Among the species tested, Pterygota mildbraedii exhibited the highest mean annual height growth (0.27 m yr−1), while Erythrina abyssinica recorded the largest diameter increment (0.30 cm yr−1). Tree presence significantly reduced crop yield (p < 0.05), with compatibility varying among species in the following order: Ficus thonningii, Markhamia platycalyx, Podocarpus falcatus, Maesopsis eminii, and Polyscias fulva. While further studies are needed, these compatibility levels indicate that integrating one or more of the tested species into farming systems may be feasible if the benefits from tree products and ecosystem services outweigh any crop competition.
A simple model of P uptake by crops as a possible basis for P fertilizer recommendations
In the Netherlands the Pw value, based on an extraction of soil P with water, is used as a basis for P-fertilizer recommendations for arable crops. Using a simple, mechanistic model of P transport in the soil the Pw value required for adequate P uptake by crops can be calculated on the basis of daily uptake requirements, root area index, P-adsorption isotherms and total amount of P taken up during a growing season. Calculated Pw values for adequate uptake are in the same range as the present recommendation scheme based on field experiments. Possible refinements of the model are discussed. For each soil the Pw value can be calculated that corresponds to the P concentrations in the soil solution according to standards set to reduce environmental pollution. Our model predicts that, unless the root area index of non-cereal crops is considerably improved, these standards cannot be met in the plough layer without affecting crop production levels. Calculations show that the present method of determining the Pw value yields a reasonable compromise between a measurement of intensity and capacity of P supply in the soil.
Tree species and pruning regime affect crop yield on bench terraces in SW Uganda
Integration of trees on farms may exert complementary or competitive effects on crop yield. This 4 year study examined novel systems in which Alnus acuminata (alnus), Calliandra calothyrsus (calliandra), Sesbania sesban (sesbania) or a mixture of all three were grown on the degraded upper part of bench terraces in Uganda; beans or maize were grown on the more fertile lower terrace during the short and long rains. Three pruning treatments (shoot, root or shoot root pruning) were applied to the tree rows adjacent to the crops; shoot prunings were applied as green manure to the woodlot from which they came. Pruning increased survival in calliandra and reduced survival in sesbania; alnus was unaffected. Pruning reduced tree height and stem diameter in alnus, but did not affect calliandra or sesbania. Maize yield adjacent to unpruned calliandra, alnus and sesbania or a mixture of all three was reduced by 48, 17, 6 and 24% relative to sole maize. Shoot pruning initially sustained crop performance but shoot root pruning became necessary when tree age exceeded 2 years; shoot root pruning increased maize yield by 88, 40, 11 and 31% in the calliandra, alnus, sesbania and tree mixture systems relative to unpruned trees. Bean yield adjacent to unpruned calliandra, alnus, sesbania and the tree mixture was 44, 31, 33 and 22% lower than in sole crops and pruning had no significant effect on crop yield. The results suggest that sesbania fallows may be used on the upper terrace without reducing crop yield on the lower terrace, whereas pruning of alnus is needed to sustain yield. Calliandra woodlots appear to be unsuitable as crop yield was reduced even after pruning
Tree stakes for climbing beans in Rwanda
Population growth and land fragmentation (farm sizes 0.3–0.6 ha) in Rwanda has resulted in reduced agricultural productivity and increased hunger and malnutrition, with 38% of children under 5 years being stunted.