Effect of Drip Fertigation under Different Fertilizer Levels on Nutrient Status in Coconut (Cocos nucifera L) Leaf

A study was conducted during 2017-18 under the All India Co-ordinated Research Project initiated in 2009 at research farm of Bihar Agricultural University, Sabour, Bhagalpur. The aim of this study was compare the nutrient concentration of coconut leaves at different nutrient levels through drip fertigation in a Randomized Block Design (RBD) with four (4) replications. Result was observed that leaf Nitrogen, Phosphorous, Sulphur, Iron, Manganese, Copper and Boron content under different fertigation treatments were not significantly different from each other. The content of micronutrients in leaf were found to increase with increasing levels of fertilizer in the treatments. Cation Exchange Capacity was positively correlated with all the leaf nutrients. Organic carbon did not show remarkable relation with plant nutrient parameters. Soil K content of all three depths was positively correlated with all the leaf nutrient elements. Soil pH value was positively correlated with leaf P content in coconut which explains that leaf P content is directly proportional to the soil pH value. Electrical conductivity (EC) of soil was also positively correlated with P, K and B concentration in coconut leaf. Correlation coefficient value between CEC and leaf nutrient contents explains that 2nd depth of soil is more important for mineral nutrition of coconut palm. Correlation coefficient values between soil P content and leaf nutrient content. Higher correlation coefficient value was found at lower soil depth between available sulphur content in soil and sulphur content in leaf of coconut. This result suggests that inherent supplying capacity of micronutrient of experimental soil is not so influential for higher plant growth, but application of N, P and K fertilizers trigger the absorption capacity for micronutrient from soil. Under different NPK levels, the applied NPK does not have significant effect on leaf N, P, S, Zn content after five (5) years of experimentation while the effect was found to be significant for few elements like K, Fe, Mn, Cu, and B. An increasing trend was observed for leaf nutrient content with increasing levels of fertilizer application.