Polycultural Productivity of Maize (Zea mays L.) as Affected by Tillage Practices, Fertilizer Rates and Intercropping Systems in the Guinea Savannah Agroecology, Ghana

Abstract

Soil impoverishment remains a major constraint to food crop production in the Guinea Savanna agroecology of Ghana. Most soils identified in this ecology are fragile and deficient in nutrients due to inappropriate management practices. To resolve this challenge, field studies were conducted to assess the polycultural productivity of maize as affected by tillage practices, fertilizer rates and intercropping systems. The study was however conducted in two cropping seasons (2016 and 2017) at Yagaba in the Mamprugu Moaduri District of Northern Ghana. Treatments consisting of 2 tillage practices (direct seeding and ploughing), 2 fertilizer application rates (zero rate [0-0-0 kg/ha NPK] and recommended rate [60-30-30 kg/ha NPK]) and 3 intercropping systems (sole maize, cowpea [Vigna unguiculata L. Walp] and soybean [Glycine max L.]) were factorially examined in three replications using randomized complete block design. Although the maize responded differently to the varied treatments, its exposure to ploughing, 60-30-30 kg/ha fertilizer rate and soybean intercropping system were in general influential in enhancing vegetative growth, yield and yield components. The responsiveness of maize to ploughing and 60-30-30 kg/ha fertilizer rate increased grain yield by 8.60% and 37.68%, respectively than their untreated controls. Regardless of not directly supplying the intercrops with the inorganic fertilizer, nodulation count and effectiveness of cowpea and soybean were improved under ploughed fields treated with 60-30-30 kg/ha fertilizer rate. The combined impact of ploughing, 60-30-30 kg/ha fertilizer rate and soybean integration resulted in higher profit returns. Hence, this study recommends to small-holder farmers in the Guinea Savannah agroecology of Ghana to adapt to the implementation of ploughing, 60-30-30 kg/ha fertilizer rate and soybean intercropping system for yield improvement and profit maximization.