全球粮食安全与营养论坛 (FSN论坛)

Monocropping vs Mixed Cropping Systems under a Changing Climate: Selected Soil Properties, Soil Organic Carbon Stocks, and Simulated Maize Yields [https://doi.org/10.1016/j.heliyon.2023.e19041] and Smallholder Farmers' Perceptions and Farm Profitability [https://track.authorhub.elsevier.com/?uuid=49d82b57-3272-4333-90cc-b484…] in drought-hotspot regions of Rwanda

Rainfed agriculture which is the mainstay of the Rwandan economy has been severely affected by prolonged droughts and climate change impacts, resulting in severe food insecurity. In the Eastern Province, the adoption of monocropping (MnC) systems at dissent which was driven by Crop Intensification Programme (CIP) may critically worsen the rain-fed agricultural gains against mixed cropping (MxC) systems practiced by the majority of smallholder farmers in drought conditions. Therefore, this study aimed to analyze and compare soil organic carbon (SOC) stocks and simulated maize biomass and grain yields under MnC and MxC systems in Kayonza District, Rwanda. The results showed that the SOC stocks of MxC soils were significantly (p < 0.001) higher (67.4 ± 1.8 tC/ha) than that of the MnC soils (52.0 ± 3.8 tC/ha). The depths avowed more highly significant (p < 0.001) SOC stocks in topsoils (0–30 cm depth) than that of the subsoils (30–60 cm depth) in the two cropping systems. This indicates that MxC sequesters more carbon and revamps soil C pools than the MnC system. The results also indicated that the simulated biomass and grain yields were highly significantly (p < 0.001) higher more and stable in MxC than in MnC fields for the entire past 20 years. Harnessing these findings, as C pools were monitored and analyzed in this study, N-biochemistry dynamics should also be conducted thereby comparing its environmental pools and impacts to both below and above-ground ecotones. The results from socio-economic perspectives showed that the majority of farmer respondents were more involved in MxC during short-rainy and dry seasons (98%) than MnC. Household heads’ sex, family size, access to credit services, access to weather and climate information, access to extension services, social group membership, and farm income were highlighted to motivate farmers to adopt the MxC systems over MnC. The MxC was, therefore, shown to be more socio-economically and ecologically beneficial to farmers than MnC under drought conditions as it was chosen and adopted by most smallholder farmers and provided higher on-farm benefits (RCR>4). Therefore, the public and non-public research institutions, NGOs, civil societies and farmer groups should facilitate smallholder farmers to freely adopt MxC to improve diverse yields under a changing climate. The MxC system was shown to be a disordered indigenous farming technology, thus it should be modernized and altered to intercropping to be fruitful, aesthetic, environmentally sustainable, and beneficial to both farm producers, planners and policy-makers.