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 itsproduction is low in the humid rainforest zone of Southern Nigeria. A field experiment was conducted inthe Rivers State University Teaching and Research Farm in Port Harcourt Nigeria, to evaluate the effectof various nitrogenous soil amendments on the growth and yield of castor bean plant (Ricinus communis).The treatments included 120kgNha-1equivalent of urea, NPK 20-10-10, poultry droppings, piggery dungand no amendment (control). These were replicated thrice and laid out in randomized complete blockdesign. A Chinese improved variety of castor bean plant (Zibocastor No 5) was planted at a spacing of 1mx 1m within and between row, at a population of 5,000 seeds per hectare. Results showed that the variousnitrogenous soil amendments significantly affected all growth and yield parameters measured, butgermination was negatively affected. Piggery dung gave the best values of 52.6cm, 24.0, 85.0cm2, 191.5,and 350gplant-1for plant height, number of leaves, leaf area, number of capsules and capsule weightrespectively, when compared to the control with 24.5, 8.0, 40.0cm2, 28.4, 153gplant-1. Results of thephysico-chemical properties of the soil showed significant increase in total nitrogen and availablephosphorus, 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.