Effect of Conservation Agriculture on Maize Yield in the Semi-Arid Areas of Zimbabwe

Abstract

Globally, a range of agronomic factors have been reported to have an impact on the performance of conservation agriculture (CA) and often determine its performance in relation to conventional agriculture (CONV). To assess this performance in Zimbabwe, 48 CA experiments were conducted by the International Crops Research Institute for the Semi-Arid Tropics in the semi-arid areas of southern Zimbabwe from 2004 to 2010, to calculate the weighted mean difference (WMD) through meta-analytical methods. The two CA practices, planting basins (Basins) and ripper tillage (Ripper), were compared with CONV. It was hypothesised that CA results improved yield compared with CONV and that the effect of CA practices on yield is affected by soil type, rainfall amount and distribution and selected management practices, which included rates of inorganic fertilisers and manures and mulching. Basins were superior to CONV in 59% of the experiments and the overall effect was significant (p < 0.001). The effect of Ripper was non-significant. The hypothesis that CA practices result in improved maize grain yield over CONV was accepted for Basins. The WMD for experiments conducted on sandy soils was 0.365 t ha −1 for Basins and 0.184 t ha −1 for Ripper, and in both cases was significant (p < 0.05). For clay soils, only the WMD for Basins was significant. A higher rainfall regime (500-830 mm) resulted in a lower WMD for Basins (0.095 t ha −1 ) and Ripper (0.105 t ha −1 ) compared with 0.151 t ha −1 for Basins and 0.110 t ha −1 for Ripper under lower rainfall (320-500 mm). The overall effect of Basins under the higher rainfall regime was not significant. There was better yield performance for Basins when the rainfall was well distributed; the reverse was noted for the Ripper. The application of 10-30 kg ha −1 of N (micro-dose range) resulted in a higher WMD for Basins than zero N application. Without N application, the WMD of Basins was not significant. For zero manure application in Basins, the WMD was 0.043 t ha −1 compared with 0.159 t ha −1 when manure was applied. The application of mulch depressed the WMD in Basins by 44% and Ripper by 89%. The hypothesis that yield performance under CA is influenced by soil type, rainfall amount and distribution, inorganic fertiliser and manure application was accepted.

Tinkering on the periphery: Labour burden not crop productivity increased under no-till planting basins on smallholder farms in Murehwa district, Zimbabwe

“…For example, Nyamangara et al (2013) reported that weeding in planting basins required double the labour in conventional tillage, and that weed growth and labour demand remained higher under planting basins tillage even after several years. Moreover, increased crop productivity under planting basins was only observed when adequate fertiliser application was achieved (Nyamangara et al, 2014). However, Mazvimavi and Twomlow (2009) observed that household labour availability did not influence adoption intensity of planting basins and might not be a major consideration for the practice.…”

Comparison of growth and yield adaptability indicators of two maize (Zea mays L.) cultivars under planting basin technique in Zimbabwe

“…The yields in various literatures can be in disagreement with the yields obtained in the current study because of the variations in the biophysical factors impacting on the type of cultivar(s) grown. Effect of basin tillage practice on yield can also be affected by soil type, amount of rainfall, management practices (which include inorganic fertilizers and organic type and rates), mulching and prevailing temperature (Nyamangara et al, 2013). The fertilizer rates of 100 kgha -1 compounds D and 90 kgha -1 ammonium nitrate contributed much on the yield.…”

“…Planting basins have been reported in literature to increase maize yields in semi-arid regions when manure and fertilizers are added (Mashingaidze et al, 2012;Nyamangara et al, 2014). The two technologies in planting basins and fertilizer application in the basins can, increase yields if the correct choice of well adapted cultivar to a particular environment is done.…”

Evidence and Lessons Learned from Long-Term On-Farm Research on Conservation Agriculture Systems in Communities in Malawi and Zimbabwe

“…These discussions were conducted with small groups of farmers (10)(11)(12)(13)(14)(15) with equal representation of males and female. The discussions were held at the different sites during annual field tours, study tours and evaluation meetings in each locality with the assistance of local extension officers, who served as translators.…”

“…However, greater water infiltration may also lead to increased waterlogging and nutrient leaching, which can negatively affect plant growth in very wet years [6]. CA has also been shown to improve different parameters of soil quality such as soil fauna, aggregate stability, soil carbon amongst others which all lead to increased productivity in the medium to long-term [7,[10][11][12][13].…”