Growth and yield response of two onion (Allium Cepa) varieties to integrated nutrient management in the transitional zone of Ghana

Abstract

Field experiments were conducted in 2016 and 2017 cropping seasons at the University of Education Winneba, Faculty of Agriculture Education, Mampong in the forest-savannah transitional zone of Ghana. The study was to evaluate the growth and yield response of two onion varieties to integrated nutrient management in the transional zone of Ghana. The treatments used were 10 t/ha Cow Dung, 10 t/ha Poultry Manure, 300 Kg/ha NPK, combination of half rate animal manure and half rate NPK 15:15:15 fertilizer (5 t/ha PM +150 kg/ha NPK; 15:15:15 and 5 t/ha CD +150 kg/ha NPK) and control (without amendment), laid out in a split plot design with 3 replications. Variety was laid as main plot while nutrient treatments were assigned to sub-plots. The onion varieties used in the study were Bawku Red and Red Creole. Application of poultry manure and cow dung and their combination with NPK fertilizer improved soil physical conditions, particularly aeration, total porosity, water holding capacity and gravimetric moisture content than the control. Soil bulk density was high in the control plots while the manure and their combinations reduced the soil bulk density. The sole cow dung and poultry manure as well as their combinations with NPK significantly increased soil organic carbon, N, P, K, Ca, and Mg concentrations over the control. Also, the total exchangeable bases, effective cation exchange capacity and percent base saturations recorded an increase over the control. Plant height and number of leaves per plant for the 5 t/ha PM + 150 Kg/ha NPK was significantly (P<0.05) higher for Bawku Red than the control while the 10 t/ha PM recorded a significantly higher number of leaves and plant height for Red Creole than the control in 2016 cropping season. The 10 t/ha PM recorded a significantly (P<0.05) greater number of leaves