Organic manure and inorganic fertilizer effect on the growth and yield of cabbage (brassica oleracea var capitata) and incidence of insect pest in the forest transition zone of Ghana

Abstract

Two field experiments were conducted at the Multipurpose Crop Nursery of the University of Education, Winneba, Mampong – Ashanti during the 2015 and 2016 cropping seasons from August to November, 2015 and June to September, 2016 respectively. The objective of the study was to determine the organic and inorganic fertilizer effects on the growth and yield of cabbage (Brassica oleraceae var capitata), and incidence of pest in the forest transition agro – ecological zone of Ghana. The experimental design used for the field experiment was a randomized complete block design (RCBD) with three replications. The treatments were: poultry manure (20 t/ha) + Cypermetrine (30 l/ha), cow dung (20 t/ha) + Cypermetrine (30 l/ha), N.P.K (300 kg) + Cypermetrine (30 l/ha), foliar + Cypermetrine (30 l/ha), poultry manure (20 t/ha) + neem leaf extract, cow dung (20 t/ha) + neem leaf extract, N.P.K (300 kg) + neem leaf extract, foliar + neem leaf extract and the control (no fertilizer and no insecticide). The results obtained revealed that the application of organic manure (poultry manure and cow dung) and inorganic fertilization is a better option for soil fertility enhancement in cabbage production. Application of poultry manure and N.P.K combined with Cypermetrine and neem leaf extract remarkably improved the growth and yield of cabbage. Cabbage yield in tons per hectare was significantly influenced by the application of poultry manure and N.P.K combined with Cypermetrine and neem leaf extract treatment. In addition, the application of Cypermetrine and neem leaf extract effectively reduced the severity of insect pest infestation. The application of Cypermetrine with poultry manure significantly reduced the percentage incidence of damage by insects on cabbage. The conclusions drawn from the research were, soil amendments with organic fertilizers remarkably improved the soil physical and chemical properties, the application of poultry manure and N.P.K fertilizers combined with Cypermetrine and neem leaf extract effectively improved the growth and yield of cabbage.