Coconut leaf vermiwash: a bio-liquid from coconut leaf vermicompost for improving the crop production capacities of soil.

Coconut leaf vermiwash (CLV) was produced from actively vermicomposting coconut leaf litter + cow dung substrate (10:1 w/w basis) by Eudrilus sp. It significantly increased the seedling vigour index of cowpea and paddy at 1: 10 and 1:15 dilutions in laboratory trials. Field trials carried out in red sandy loam soil (Arenic Paleustuits) resulted an increase of 36% fresh biomass weight of cowpea with application of CLV at 1: 10 dilution. In maize, increase in cob yield by 5-10% and in bhendi (okra) 22-33% increase in fruit yield were recorded at 1: 5 dilutions of CLV. A concomitant increase in populations of general and plant beneficial microorganisms and soil enzyme activities in the rhizosphere of CLV-applied plants were also recorded. Soil organic carbon content increased in the CLV-applied plots in all the crops studied, but the total N, available P and K content in soil varied in different crops. The study indicated that CLV must be used in graded doses. Its application increased the crop production capacities of soil by (i) enhancing the organic carbon contents in the soil and (ii) increasing the populations of the soil microorganisms, particularly plant beneficial ones, and their activities which would have facilitated increased uptake of the nutrients by the plants resulting in higher growth and yield.