Physiological diversity of rhizobia nodulating promiscuous soyabean in Zimbabwean soils

Rhizobial isolates were obtained from nodules of promiscuous soyabean varieties Hernon 147 and Magoye and specific Roan grown in a range of Zimbabwean soils. A total of 129 isolates authenticated as true rhizobia were characterized using growth rate, elasticity, colour, size, colony shape, acid/alkali production on YEM and tolerance to low and high pH, elevated temperature and salt concentration. Isolates separated into 2 major clusters at a similarity level (%SSM) of 66%. Cluster I contained isolates forming dry colonies (77%) which separated into 9 groups and Cluster II contained those forming the wet colonies (23%) with 4 groups. Acid and salt tolerance patterns did not differ among the two main clusters (the dry and the wet colony types). More isolates forming wet colonies (47%) survived at 40°C than those forming dry colonies (13%). Salt, temperature and acid pH tolerance were not related to geographic origin of the isolates. The promiscuous soyabean variety Magoye nodulated with the widest range of rhizobia (12 groups) followed by Hernon 147 (11 groups) and then Roan (9 groups). Guruve soils had the most diverse range of isolates belonging to 12 groups followed by those from Chiweshe (9 groups) and then those from Chikomba (8 groups). Our results indicate that soyabean is nodulated by a wide range of indigenous rhizobia in African soils

Symbiotic effectiveness and host ranges of indigenous rhizobia nodulating promiscuous soyabean varieties in Zimbabwean soils

Presence of indigenous rhizobia nodulating promiscuous soyabean was determined in 92, mainly sandy soils, from wetter agro-ecological zones of Zimbabwe suited to soyabean production. A total of 129 isolates were obtained from nodules of promiscuous soyabean varieties, Magoye and Hernon 147, and a specific variety, Roan grown in potted soils. Magoye nodulated in 80%, Hernon 147 in 50% and Roan in only 25% of the 92 soils tested. Rhizobia populations ranged from undetectable to 2.4×104 cells g-1 of soil. Twenty-one of these isolates were tested for symbiotic effectiveness on two varieties, promiscuous Magoye and specific Roan. Differences in parameters such as nodule numbers, nodule weights and total N fixed reflected diversity among the indigenous isolates. Three isolates had significantly higher N2-fixing potential in comparison with the commercial strain MAR 1491 on promiscuous Magoye. Host ranges of 34 isolates were evaluated on nine legume species: Arachis hypogaea, Cajanus cajan, Crotalaria juncea, Glycine max, Macroptilium atropurpureum, Phaseolus vulgaris, Sesbania sesbania, Vigna subterranea, Vigna unguiculata. Of these 34 isolates, 33 formed nodules with M. atropurpureum of which 61% were moderately effective to very effective while all nodulated V. unguiculata with 58% being moderately effective to very effective. Twenty-eight isolates nodulated V. subterranea and C. cajan (short season variety) with 76 and 36% of these being moderately to very effective, respectively. None of the isolates formed nodules on Phaseolus vulgaris, Arachis hypogaea or Sesbania sesban. Our results indicate that the ability of even specific varieties of soyabean to nodulate with indigenous isolates in African soils is greater than generally assumed

Assessment of innovations for sustainable livelihoods for smallholder farmers in response to changing climates in semi-arid Zimbabwe through farmer perceptions

Increasing sources of livelihoods and of income through appropriate innovation platforms may contribute to reduced food insecurity and increase resilience of rain-fed smallholder farmers in semi-arid areas of Zimbabwe. Negative impacts of climate change and variability are mainly projected for smallholder production. Small grain and livestock production will remain important sources of livelihoods for Zimbabwean communal farmers in semi-arid areas in future climates. Platforms for innovations for crop and livestock production need to be strengthened to decrease vulnerability of smallholders. The objectives of this study were to assess agricultural innovations in semi-arid smallholder areas and suggest innovations which may improve livelihoods in current and future climates through analysis of farmer perceptions. Sites selected were semi-arid Matobo (AER IV, V) and Chiredzi (AER V) districts of Zimbabwe. Livelihood sources were identified through household surveys. Interventions/strategies introduced by institutions and farmer organizations and possible gaps in innovations were identified through focus group discussions and key informant interviews. Climatic factors in both districts and soil fertility in Matobo were some of the main constraints to production. Crop technologies/interventions by institutions and farmer organizations included irrigation for horticulture, soil fertility management, improving access to fertilizer, and access to grain markets in Matobo. In Chiredzi technologies/interventions included small grain production and soil fertility management innovations. Farmers particularly in Chiredzi identified livestock production to be one of the most important sources of livelihoods. Poor informal markets and bargaining power as well as shortage of grazing land, in addition to pests and diseases were however cited as some of the main constraints to livestock production. For livestock systems there may be need for enhancing platforms for fodder production and grazing management and market access to increase income for households. Small grain production may be enhanced by innovations in processing

An assessment of gender sensitive adaptations options to climate change in smallholder areas of Zimbabwe, using climate analogue analysis and considering farmer perceptions

Current projections suggest that the impacts of warmer climates on smallholder production by the middle of this century, are excpected to be mainly negative. Both the livelihoods and food security of smallholder households can be improved through suitable strategies for handling climate- induced risks and socio-economic and biophysical constraints. This paper describes the use of climate analogue areas together with an assessment of farmers´ perceptions, within the framework of the project CALESA. In particular, it considers them as tools for climate-risk analysis and assessment of adapation options. The importance for mainstreaming gender sensitive options for climate change planning and policy is also herewith illustrated. Climate analogues for 2050s were identified in smallholder areas of Zimbabwe based on 30 years metereological data. Pairs of sites with similar annual rainfall totals, which differed by 2-4 degrees Celsius in mean annual temperature (following the forecast effects of global warming for the 2050s) consist of Chiredzi which represent Matobo for drier areas, and Kadoma for wetter areas, which represent Mazowe/Goromonzi. Preliminary results for the 2010/2011 cropping season show different preferences for crop management strategies, particulalry between the dry analogue pair, with respect to crops choices as well as soil and water management strategies. In drier areas, implications are for increased uptake of small grains, in 2050s climates. For wetter climates, soil and water management stragegies are important options for smallholders. Gender issues for differently managed households seem to vary across sites. At drier sites, gender issues include labour for production and processing of the small grains, against a background of male labour migration. At wetter sites, access to draft power, labour, agricultural assets, social and financial capital in differently managed households are important for increasing adoption of effective crop management strategies

Residual nitrogen benefits of promiscuous soybeans to maize under field conditions

(African Crop Science Journal 1999 7(4): 375-382

Residual Nitrogen Benefits of Promiscuous Soybeans to Maize Under Field Conditions

Residual N benefits of incorporated stover of two promiscuous and two specific soybean varieties to a subsequent, unfertilised maize crop were determined at three sites. Soybean stover was either incorporated onto field plots previously under four soybean varieties or removed soon after harvesting. Maize yield increases were higher when promiscuous soybean stover was incorporated compared to where specific soybean stover was incorporated. Yields were higher with stover incorporation compared with stover removal. Plots where soybean stover was removed gave significantly higher maize grain yield (1 - 2 t ha-1) on-farm and 3 - 5 t ha-1 on-station compared to the control (maize after maize) plots which gave 0.4 t ha-1 on-farm and 2 t ha-1 on station. Our results indicate that soybean has significant residual fertility effects for maize and maize-based cropping systems.Les effets r\ue9siduels b\ue9n\ue9fiques de l\u2019azote des fanes de deux vari\ue9t\ue9s de soja non sp\ue9cifiques et de deux vari\ue9t\ue9s de soja sp\ue9cifiques incorpor\ue9s dans une culture ult\ue9rieure de ma\uefs sans apport d\u2019engrais, ont \ue9t\ue9 d\ue9termin\ue9s dans trois sites d\u2019essai en milieu r\ue9el. Les rendements du ma\uef\uefs ont augment\ue9 quand les fanes de vari\ue9t\ue9s non sp\ue9cifiques de soja \ue9taient incorpor\ue9es compar\ue9s aux r\ue9sidux de soja sp\ue9cifiques. Les rendements \ue9taint plus \ue9l\ue9v\ue9s avec l\u2019incorporation de fanes en comparaison de l\u2019enl\ue8vement des fanes. Les parcelles ou les fanes de soja \ue9taient enlev\ue9es ont donn\ue9 de rendements en grains significativement plus \ue9l\ue9v\ue9s en milieu r\ue9el (1 - 2 t ha-1) et station (3 - 5 t ha-1) plus que les parcelles t\ue9moins (ma\uefs sur ma\uefs) qui ont donn\ue9 0.4 t ha-1 en milieu r\ue9el et 2 t ha-1 en station. Nos r\ue9sultats montrent que le soja a des effets r\ue9siduels de fertilit\ue9 significatifs sur le ma\uefs et les syst\ue8mes de cultures \ue0 base du ma\uefs

An Assessment of Gender Sensitive Adaptation Options to Climate Change in Smallholder Areas of Zimbabwe, Using Climate Analogue Analysis

Climate analogues can be used to assess climate–induced risks and adaptation options for smallholder farmers. Surveys were carried out in smallholder areas at two 2050s climate analogue sites to assess smallholder climate-induced risks, farmers’ perceptions, and adaptation options, with a gender perspective. Pairs of sites selected had similar annual rainfall totals but differed in mean annual temperature by 2–4 °C. For drier areas Chiredzi was hypothesised to represent Matobo, and for wetter areas Kadoma was hypothesized to represent Mazowe/Goromonzi 2050s climates. Differences in crop management strategies and gender issues vary across sites. At the drier analogue pair, higher proportions of households grew small grains in Chiredzi compared to Matobo. Implications are for increased uptake of small grains, in 2050s climates for Matobo farmers. Gender issues include labour for production and processing of the small grains, against a background of male labour migration. For wetter climates, soil and water management strategies are important options for smallholders. Accesses to draft power, labour, agricultural assets, social and financial capital in differently managed households are important for increasing adoption of effective crop management strategies