Conservation Agriculture in Semi-Arid Zimbabwe: A Promising Practice to Improve Finger Millet (Eleusine coracana Gaertn.) Productivity and Soil Water Availability in the Short Term

Abstract

Increasing within-season dry spells in Southern Africa in recent years have generated growing interest in conservation agriculture (CA) to secure crop yields, especially under rainfed systems. This study aimed to evaluate the effects of CA on finger millet’s (Eleusine coracana (L.) Gaertn) growth, yield and water use efficiency on nutrient-depleted sandy soils. Five treatments, namely (conventional tillage (control), conventional tillage + mulch (partial CA1), reduced tillage only (partial CA2), reduced tillage + mulching (partial CA3) and reduced tillage + mulching + intercropping (full CA)) were evaluated over two consecutive cropping seasons (2015/16 and 2016/17) on-farm in the village of Chidora in Hwedza District, southeast Zimbabwe. All mulched treatments had 15–32% more soil water content over the two growing seasons compared to the control. The higher soil water content under the mulched treatments significantly improved finger millet growth and development during both seasons as evidenced by the lower number of days to emergence (3 days less), greater shoot biomass, higher number of productive tillers and higher number of fingers produced. The full CA treatment achieved the best finger millet grain yield of 1.07 and 1.29 t ha−1 during the 2015/16 and 2016/17 seasons, respectively. Full CA, partial CA3 and partial CA1 increased finger millet grain yield by 70%, 14% and 17% during the 2015/16 cropping season compared to the control. During the 2016/17 cropping season, a similar trend in finger millet grain yield was observed. Full CA was also among the most efficient methods in terms of water utilization (WUE), especially during the 2015/16 season. We concluded that CA, particularly when practiced in full, was more effective at offsetting the water limitations imposed by intra-seasonal dry spells on finger millet and significantly improved productivity.

Continuous cropping system altered soil microbial communities and nutrient cycles

“…The contents of AP and AN after continuous soybean cropping for 13 years were significantly higher than those after 3 or 5 years. Soil nutrients exhibited no decrease after long-term continuous cropping, indicating that the lack of plant nutrients may not directly cause plant diseases (Mbanyele et al, 2022).…”

Finger millet (Eleusine coracana) improvement: Challenges and prospects—A review

“…For example, NGRC04789, NGRC04849 and NGRC06490 are landrace selections of finger millet favoured in Nepal for blast resistance, drought tolerance and medicinal value (Luitel et al, 2020). In Zimbabwe, most finger millet production is based on unimproved landrace varieties (Mbanyele et al, 2022). Landraces such as Tsa'ada, Tselim and Keyih with different seed colours are widely preferred finger millet in Northern Ethiopia, meeting consumers' needs and market demands (Tsehaye et al, 2006).…”

Managing multiple stressors for sustainable livelihoods in dryland ecosystems: Insights and entry points for resource management

“…Meanwhile, China's drought‐stricken Gansu province uses small spherical sub‐surface tanks to collect rainwater to supply water to 2 million households (Zhu, 2003). As another example, conservation agriculture treatments in southern Africa effectively improved the protection of ‘green water’, with all mulching treatments providing 15%–32% more soil water content in both growing seasons compared to controls, effectively improving finger millet growth and development during both seasons and leading to an increase in finger millet grain yield of 70% (Mbanyele et al, 2022). Community‐level climate adaptation strategies and guidelines for grassroots action, such as micro‐watershed management and conservation in small‐scale local agriculture, can reduce disaster risks and increase local adaptation capacity (Dobson, 2017; Mihunov et al, 2019).…”