Nitrogen Fertilizer Replacement in Legume Cereal Rotations

Abstract

Sustainable food production is one of the major global challenges, exacerbated by climate change, increasing population, and natural resource degradation, including soil degradation and loss of biodiversity (Pretty and Bharucha, 2014; Vanlauwe et al., 2014). Cropping systems that specialize in one or two crops, with little attention to crop diversity, may lead to biological and physical soil degradation (Kirschenmann, 2002; Tanaka et al., 2010). Annual cropping systems, which include diverse crops such as cereals, legumes, and oilseeds, may be economically viable options for farmers. Diversifying crops in cropping systems also influences the soil environment and diversity of soil organisms (Williams et al., 2023; Yang et al., 2020). It is crucial to consider the synergistic or antagonistic relationships of crops in cropping systems for sustainability and resilience in agricultural systems (Kirschenmann, 2007). Legumes play a major role in the sustainability of cropping systems, primarily due to their contribution of biologically fixed N and other beneficial effects, such as breaking pest and disease cycles for non-legume crops (Agegnehu et al., 2014; Peoples et al., 1995; Siddique et al., 2008). In Ethiopia, crops and cropping systems are diverse due to large agroecological and cultural diversity, which in turn leads to variable cropping patterns. The greater reliability of return is the main feature of multiple cropping, compared to monocropping. This report summarizes the contribution of crop rotation to the yield of major cereal crops after major precursor legumes based on legacy research data on cereal-legume rotations. Determining the contribution of major leguminous crops to subsequent cereal crops in terms of yield and soil fertility will help compensate for the rate of nitrogen fertilizer required, thereby enabling integration into digital fertilizer advisory services