EFFECT OF NITROGENOUS SOIL AMMENDMENTS ON SOIL PHYSICO-CHEMICAL PROPERTIES AND PERFORMANCE OF CASTORBEAN PLANT (Ricinus communis) IN RIVERS STATE, NIGERIA

Abstract

The castor bean seed when cooked and fermented, is a staple food condiment in Nigeria, but its production is low in the humid rainforest zone of Southern Nigeria. A field experiment was conducted in the Rivers State University Teaching and Research Farm in Port Harcourt Nigeria, to evaluate the effect of various nitrogenous soil amendments on the growth and yield of castor bean plant (Ricinus communis). The treatments included 120kgNha -1 equivalent of urea, NPK 20-10-10, poultry droppings, piggery dung and no amendment (control). These were replicated thrice and laid out in randomized complete block design. A Chinese improved variety of castor bean plant (Zibocastor No 5) was planted at a spacing of 1m x 1m within and between row, at a population of 5,000 seeds per hectare. Results showed that the various nitrogenous soil amendments significantly affected all growth and yield parameters measured, but germination was negatively affected. Piggery dung gave the best values of 52.6cm, 24.0, 85.0cm 2 , 191.5, and 350gplant -1 for plant height, number of leaves, leaf area, number of capsules and capsule weight respectively, when compared to the control with 24.5, 8.0, 40.0cm 2 , 28.4, 153gplant -1 . Results of the physico-chemical properties of the soil showed significant increase in total nitrogen and available phosphorus, and a decrease in exchangeable calcium and magnesium with no significant changes in pH; following soil amendment and cropping. Amending the soil with piggery dung increased yield by 397.0% over the control.