Understanding the factors influencing fall armyworm (Spodoptera frugiperda J.E. Smith) damage in African smallholder maize fields and quantifying its impact on yield: a case study in eastern Zimbabwe

Open Access Article; Published online: 26 Jan 2019Fall armyworm (FAW, Spodoptera frugiperda J.E. Smith) is an invasive lepidopteran pest established in most of sub-Saharan Africa since 2016. Although the immediate reaction of governments has been to invest in chemical pesticides, control methods based on agronomic management would be more affordable to resource-constrained smallholders and minimize risks for health and the environment. However, little is known about the most effective agronomic practices that could control FAW under typical African smallholder conditions. In addition, the impact of FAW damage on yield in Africa has been reported as very large, but these estimates are mainly based on farmers' perceptions, and not on rigorous field scouting methods. Thus, the objectives of this study were to understand the factors influencing FAW damage in African smallholder maize fields and quantify its impact on yield, using two districts of Eastern Zimbabwe as cases. A total of 791 smallholder maize plots were scouted for FAW damage and the head of the corresponding farming household interviewed. Grain yield was later determined in about 20% of these fields. FAW damage was found to be significantly reduced by frequent weeding operations and by minimum- and zero-tillage. Conversely, pumpkin intercropping was found to significantly increase FAW damage. FAW damage was also found to be higher for some maize varieties, although these varieties may not be the lowest yielding. If the incidence of plants with FAW damage symptoms recorded in this research (32–48%, depending on the estimate used) is commensurate with what other studies conducted on the continent found, our best estimate of the impact of FAW damage on yield (11.57%) is much lower than what these studies reported. Although our study presents limitations, losses due to FAW damage in Africa could have been over-estimated. The threat that FAW represents for African smallholders, although very real, should not divert attention away from other pressing challenges they face

Conservation agriculture/farmers mechanization: Africa RISING science, innovations and technologies with scaling potential from the Ethiopian Highlands

United States Agency for International Developmen

Evaluation of suitable water lifting and on-farm water management technologies for the irrigation of vegetables and fodder in Lemo district, Ethiopia

United States Agency for International Developmen

Drivers of Agricultural Mechanization and Mechanized Conservation Agriculture: Synthesis from Experience of Successful Countries

Summary Based on literature, this paper reviews drivers of agricultural mechanization and mechanized conservation agriculture (CA) focusing on the experience of selected countries where mechanization and CA have been adopted at a large scale. The synthesis followed gradient approach where drivers of mechanized CA were evaluated considering different types of farm power use (mechanical, draft animal and manual), tillage types (conservation and conventional) and farm size (large and small holding). In the analysis, emphasis was given to major drivers of mechanized CA; namely, policies, markets, and institutional arrangements. Review results show that the expansion of mechanized CA is less proportionate across the World. Wider expansion has been observed in Latin America, North America, Australia, and South Asia regions whereas countries in sub-Saharan Africa (SSA) are the least in terms of the adoption of mechanized CA. The success of mechanized CA in the above indicated regions are mainly related to the availability of conducive markets, institutional and policy environments and the integration of diverse actors that helped in putting the necessary inputs, information and knowledge together. These all assisted in creating incentives to local CA-related machinery manufactures, machinery importers, distributors, local service providers, and farmers. Generally, literature supports that the expansion of mechanized CA is strongly related to the development, distribution and use of CA related farm machineries through the integrated efforts of different actors including private companies, international and national research institutes, government and non-government organizations, farmers, and extension service providers

Estimating lime requirements for tropical soils: Model comparison and development

Acid tropical soils may become more productive when treated with agricultural lime, but optimal lime rates have yet to be determined in many tropical regions. In these regions, lime rates can be estimated with lime requirement models based on widely available soil data. We reviewed seven of these models and introduced a new model (LiTAS). We evaluated the models’ ability to predict the amount of lime needed to reach a target change in soil chemical properties with data from four soil incubation studies covering 31 soil types. Two foundational models, one targeting acidity saturation and the other targeting base saturation, were more accurate than the five models that were derived from them, while the LiTAS model was the most accurate. The models were used to estimate lime requirements for 303 African soil samples. We found large differences in the estimated lime rates depending on the target soil chemical property of the model. Therefore, an important first step in formulating liming recommendations is to clearly identify the soil property of interest and the target value that needs to be reached. While the LiTAS model can be useful for strategic research, more information on acidity-related problems other than aluminum toxicity is needed to comprehensively assess the benefits of liming