Potential Use of King Coconut Husk as a Nutrient Source for Organic Coconut Cultivation

Abstract

King coconut husk (KCH) is a waste material from nut water processing industry which has no identified economic value, rather causing environmental problems. The KCH was used to develop a nutrient supplement material (NSM) by controlled combustion inside a kiln. Among the three categories of moist, semi-dry and dry coconut husk used for combustion, semi-dry KCH was found to be the best for processing in terms of time taken for the processing and ease of handling. The product was analyzed for nutrient availability and found that it contained considerable amounts of macro and micro nutrients. The developed NSM was then tested under field condition to investigate the potential for it to be used as a source of nutrient in coconut cultivation. The treatments were: T1- Recommended straight fertilizer (N, P, K) for coconut, T2- NSM was added as a source of K while other nutrients were same as in T1, and T3 - K source supplied from sulfate of potash while other fertilizers were similar to T1. Three months after treatment application, representative soil samples were extracted and tested for soil pH, electrical conductivity and soil exchangeable potassium levels. According to the results, the product contained considerable amounts of macro nutrients including N (2.1 - 2.4%) and K (8.8 - 13.1%), and micro nutrients including Zn (1350 - 1522 ppm) and Cu (61.2 - 62.5 ppm). The K content of NSM was around three times higher than the K content of other locally available organic manure. This indicates the potential of the product as a source of nutrient. Even though the pH of developed NSM product was higher (10.6), after application this product into soil, there was no significant difference among treatments. The NSM incorporated treatment showed significantly higher soil K content compared to other treatments which indicates its potential to be used as a source of K with organic manure for young coconut.