Effect of Vermicompost, Vermiwash and Application Time on Soil Physicochemical Properties

Abstract

Vermicomposting results in the production of two bio-fertilizers, vermicompost and vermiwash. The bio-fertilizers were applied to 4kg of loam-clay soil over a period of 40 days. The effect of the vermicompost, vermiwash, application time and their combined effect on soil pH, electrical conductivity and nitrogen, phosphorous and potassium content were analyzed. Increasing the vermicompost quantity decreased the soil pH, electrical conductivity and nitrogen content, however, this resulted in a slight increase in the phosphorous content but the potassium content remained unaltered. Increasing the vermiwash quantity increased the soil pH, electrical conductivity and potassium content but resulted in reduced nitrogen and phosphorous content. In addition, increasing the application period of either the vermicompost or the vermiwash resulted in increased soil pH, electrical conductivity, phosphorous and potassium content but resulted in reduced phosphorous content. The reduction of the soil nitrogen content is attributed to de-nitrification, whilst the increase in phosphorous content is attributed to increase in soluble phosphates and release of nutrients into the soil due to microbial activity in the bio-fertilizers. Furthermore, loam-clay soils have good absorbing properties for potassium. The soil properties and micro-organisms present in the bio-fertilizers play a critical role on the modification of the soil physicochemical properties