Selection of annual legumes for incorporation into rice farming systems

Abstract

Legumes are often recommended for inclusion into rice farming systems to provide organic matter and nitrogen. Thus, a study evaluated the growth, yields and nitrogen dynamics of four popular legumes, namely Sesbania, Mungbean, Cowpea and French bean using "N, when grown in a rice soil. Sesbania produced the highest quantity of nitrogen-rich dry matter. In contrast, French beans produced the lowest quantity, which was low in nitrogen. Dry matter contents of other legumes available for incorporation were greater than in French beans. Nitrogen dynamics illustrated the very high nitrogen fixing capacity of sesbania, while the eficiency of symbiotic fixation was low in French beans. The net nitrogen balance of sesbania was high, followed by cowpea and mungbean. The study illustrated the benefits of using sesbania for the purpose of adding green manure and nitrogen. If a food legume is to be used, species such as cowpea or mungbean was more suitable to achieve the stated objectives than French bean, which produced the highest economic yield.

Effect of Soybean Plant Populations in a Soybean and Maize Rotation

“…Net N balance is the potential N contribution of a legume to the environment (Sangakkara, 1995). Values in this study ranged from −48 to +17 kg N ha −1 (Table 2).…”

Agronomic regeneration of soil fertility in tropical Asian smallholder uplands for sustainable food production

“…Senaratne & Hardarson 1985;Holford & Crocker 1997). However all legumes do not fix nitrogen in large quantities, and species such as Phaseolus beans do leave a negative balance of N in soils (Sangakkara & Attanayake 1995). Thus in general, the conclusion of most studies is that the removal of a harvested product in a legume crop, especially in weaker N fixing species such as Phaseolus beans, a popular legume in most tropical upland systems removes more N than that added via residues.…”