Potential of agroforestry in improving soil productivity in semi-arid farming regions of Zimbabwe

Abstract

Crop productivity in semiarid regions is constrained by low inherent soil fertility and limited moisture. A large (>70%) proportion of communal farmers is located in semi-arid regions, which are characterized by erratic rainfall and infertile and acidic soils with poor water-holding capacity. Low soil moisture recharge, high evapotranspiration, and reduced nutrient content drastically reduce crop yields, exposing the rural population to acute food and nutrition deficiencies. Low soil productivity is exacerbated by a lack of adequate farming resources among communal farmers. Farmers cannot afford to purchase expensive soil fertility-improving inputs, such as chemical fertilizers, and are devoid of irrigation infrastructure. Hence, sustainable in-field soil moisture and fertility conservation strategies are required in the semiarid regions of Zimbabwe. Many strategies, such as straw mulching, conservation agriculture (CA), fanya juu, crop rotation, and agroforestry (AF), are possible strategies for enhancing soil moisture conservation and fertility. Considering the rampant deforestation in the semi-arid communal areas of Zimbabwe, the AF is potentially important in restoration of soil production. The AF is when farmers intentionally integrate multipurpose trees with field crops and/or animals in their farms to boost productivity. Agroforestry increases soil productivity by improving soil moisture holding capacity, fertility, and soil conservation. Unfortunately, the potential of AF in agro-systems is limited, and hence, there is low uptake among smallholder farmers in Zimbabwe. Therefore, this review explores the ways in which agroforestry can be used to increase soil productivity in semiarid regions.