Abstract
Earthworm digested wastes (vermicompost) are being produced in increasing quantities and there is much interest in developing new markets for these products. In this paper, the responses of wheat (Triticum aestivum var. Einstein and Xi19) to vermicompost additions and to combinations of vermicompost and inorganic NPK fertilizer in field and glasshouse environments are considered. Plant response was determined by measuring a range of ontogenetic parameters (plant growth, chlorophyll content, fertile ears, tiller number and grain yield). The individual treatments involved the addition of 1, 10 and 30 t ha−1 of vermicompost to soil, or the coapplication of 1, 10 and 30 t ha−1 of vermicompost plus NPK fertilizer where the N addition rate was normalized to 150 kg N ha−1. Photosynthetic pigment development, plant growth, and yield were reduced in all treatments in the absence of inorganic fertilizer. However, all coapplication treatments resulted in similar yields to NPK fertilizer alone in both field and glasshouse experiments. It is our conclusion that vermicompost alone cannot provide a viable substitute for inorganic fertilizer without causing a significant loss of yield; however, it may enhance soil quality if integrated into conventional arable cropping practices which use inorganic fertilizers.
