A comparative assessment of nutrient partitioning in healthy and root (wilt) disease affected coconut palms grown in an Entisol of humid tropical Kerala

Abstract

Root (wilt) is a predominant phytoplasmal disease affecting coconut (Cocos nucifera L.) palms and to sustain the palm health and productivity, better nutrient management practices are required. The objective of this research was to understand the uptake pattern and the partitioning of nutrients in the total biomass of healthy and root (wilt) diseased palms grown in humid tropical Entisol of Kerala. 5 coconut palms each were selected from diseased palms viz., Early (DE), Middle (DM) and Advanced (DA) category along with the control, which is Apparently Healthy palm (AH), without any diseases. The total biomass component with respect to each part viz., leaf (L), petiole (P), spadix (S), spathe (Sp), stem (St), leaf sheath fiber (LSF), husk (H) and nuts (copra:C + shell (Sh)) (N) were estimated. Nutrient uptake by the entire biomass uptake is classified as 1. Recyclable portion (L, P, S, Sp, H, LSF and Sh) 2. Removable portion (C) 3. Reserve biomass (St) and then computed the nutrient partitioning by standard analytical procedures. For all nutrients except Mg, reserve biomass had the greatest nutrient uptake followed by recyclable biomass and removable biomass components. Among the nutrients, potassium recorded the highest total uptake. In AH palm, the total uptake of potassium was 1075 g per palm, whereas it was 407.3 g per palm in the diseased palms. The total uptake of nutrients which showed a significant relation with disease index followed the order K > N > Ca > S > P > Mg in apparently healthy palms and N > K > Ca > S > P > Mg in diseased palms. The percentage reduction in total uptake of N, P, K, Ca, Mg, S and B by diseased palms in comparison with healthy palms was 36.5, 37.6, 57.5, 44.1 23.3, 43.7 and 48.9. The results of the study indicated that the pattern of nutrient uptake in the different biomass components of apparently healthy and root (wilt) disease affected palms are significantly different. This can instigate the formulation of appropriate nutrient management strategies in coconut with emphasis on its residue recycling potential