Effects of Calcium Nitrate Levels and Soaking Durations on Cocopeat Nutrient Content

Cocopeat, a by-product of the coconut (Cocos nucifera L.), is an important soilless media that contains high potassium (K), sodium (Na), and electrical conductivity (EC) depending on its source. Methods for extracting these elements and thus lowering EC are yet to be standardized. This study was therefore carried out to investigate two extraction methods of these elements in cocopeat. A greenhouse pot experiment was carried out at the Climate and Water Smart Agriculture Centre of Egerton University, Kenya. It was laid out in a 5 × 4 factorial completely randomized design. Five soaking durations (12, 24, 36, 48, and 72 hours) and four calcium nitrate (Ca(NO3)2) levels (0, 60, 100, and 150 g) were used. The experiment was done in two folds: the leachate and treated cocopeat examination for their chemical properties. The General Linear Model procedures were used for Analysis of Variance at (P ≤ 0.05). The results showed that the addition of Ca(NO3)2 100 g extracted significantly more K and Na in the leachate than Ca(NO3)2 0.0 g and 60 g. The EC levels in the leachate increased with the application levels of Ca(NO3)2 while the pH levels were reducing. In the treated cocopeat, Ca(NO3)2 100 g and soaking duration 36 hours significantly reduced K and Na and sufficiently supplemented Ca and N. Irrespective of Ca(NO3)2 and soaking durations, after the cocopeat is washed, the EC and pH values fall within their suitable ranges. There was a strong negative correlation between Ca and Na, Ca and K, and between Na and EC. Also, strong positive correlation between Ca and N and Ca and EC. Effective supplementation of Ca and N, and optimal reduction of K and Na by 78.44% and 92%, respectively can be achieved with 100 g of Ca(NO3)2 1.5 kg−1 of cocopeat in 15 liters of water with a soaking duration of 36 hours.