Maize-Legumes Rotation Effects on Growth and Yield of Maize in a Semi-Arid Agro-Ecology in Northern Ghana

Abstract

Low soil fertility is the most significant agricultural production constraint also mentioned by resource-poor Farmers participating in the Annual Review and Planning Sessions organized under the auspices of the Research, Extension and Farmer Linkage Committees across Ghana. It is in an attempt to find a very cost effective but yet cheaper and most sustainable solution that this work was undertaken. A six-year field trials were conducted at the Manga Agricultural Research Station near Bawku in the Upper East Region in northern Ghana to determine the most suitable grain legume rotation partners for maize relative to continuous cultivation of maize (Zea mays L.) after maize, which is often practiced by cereal farmers under inherently poor soils conditions. The grain legumes evaluated were cowpea [Vigna unguiculata (L.) Walp.], soybean [Glycine max (L.) Merr.], groundnuts (Arachis hypogaea), pigeon pea [Cajanus cajan (L.) Millsp.], mucuna (Mucuna pruriens (L.) DC and green gram (Vigna radiate (L.) Wilczek. The trial was established in a randomized complete block with four replications. Growth, development, grain yield and its components and some derived variables were computed. Mean grain yield of maize in the first year, preceding rotation was 2055 Mt ha-1. All the grain legumes recorded significantly greater grain yields as compared to the farmers’ practice of continuous cultivation of maize. This is consistent with the very low Carbon and Nitrogen ratios recorded under the grain legumes as compared to the continuous maize treatment. Maize after pigeon pea, groundnuts and cowpea recorded consistently superior grain yields as compared to the other grain legumes and farmers’ practice. Mean grain yield increment recorded for one of the first cycle of rotation was as high as 62% over continuous cropping of maize. Similarly, mean grain yield increment of maize after pigeon pea, groundnut and cowpea over continuous maize was 42.5, 41.5 and 31.5% respectively, over the farmer practice. It was concluded that continuous crop rotation of grain legumes with maize resulted in higher maize grain yields as reflected in the superior economic returns on a sustainable basis than the current farmers’ practice of continuous cropping of maize after over the years. This obviously has important implications on food security at the farmer household level not only in northern Ghana but equally so in other countries with similar, agro-ecology zones in the African and Asian Continents.