EFFECTS OF ORGANIC SOIL AMENDMENTS IN NUTRITION OF BANANA PLANTS

Abstract

Soil degradation is among the most common causes of low productivity of bananas in Kenya. Four organic soil amendments were evaluated at the Regional Research Centre at Embu during the 2006 long rainy season for their relative contribution to soil fertility in bananas. The amendments tested were: farmyard manure, poultry litter, Tagetes minuta and Tithonia diversifolia. A control treatment was also included in which no amendment was used. The treatments were arranged in a Randomized Complete Block Design replicated ten times. Ten tissue-cultured banana plants of the cultivar Grand Nain grown in polyethylene sleeves containing sterilized forest soil were used for each treatment. The amendments were incorporated in the soil at the rate of 5% (w/w) per plant. The study was conducted for a period of 90 days. Plant growth and soil fertility data were collected at the termination of the study. Plant growth data included plant height, pseudostem girth, number of leaves and plant biomass, which were analyzed using SAS. Residual soil fertility was determined through fertility analysis conducted at the National Agricultural Research Laboratories. Significant (P<0.05) improvements were observed in plant growth as well as residual levels of major soil nutrients in all amended soils. Poultry manure had the strongest influence on both parameters, showing increases of 54% and 190% in residual levels of nitrogen and phosphorous, respectively, compared to the control. Plant height, girth and total plant biomass increased by 26%, 42% and 46%, respectively over the control due to the application of this amendment. The results indicate that the organic soil amendments are suitable alternatives for restoration of soil fertility and have potential to improve banana productivity in small-holder farms when applied periodically.