The Use of Vegetable- and Bio- Waste Composts: Effects on Forage Maize Production and Soil Properties

Abstract

Biodegradable municipal and farm waste compost application to agricultural land is increasing following the implementation of regulations which restrict the disposal of organic rich materials in landfills. Compost application, however, needs to ensure sustainable agricultural development. A field study was conducted on sandy loam soil to assess the agronomic benefit and the environmental risk from nitrate leaching following biowaste (containing kitchen, garden, paper and cardboard waste) and vegetable waste compost use in agriculture. The two composts were applied to forage maize production at three rates, ranging on average from 90 to 325 kg total N ha-1 yr-1. Mineral N fertilizer and non-amended soil was used for comparison. Forage maize response to compost application and mineral fertilization was limited in both years of application, as the soil itself met the N requirements of the crop, through the mineralization of soil inherent N. The monitoring of soil mineral N suggested that vegetable waste compost (C: N of 10.5) resulted in similar amounts of plant available N with mineral fertilizer N. Biowaste compost with C: N of 20 resulted in limited mineralization of compost N. In soils with high N mineralization potential applying biowaste compost resulted in lower risk of nitrate leaching. This study provided evidence to suggest that biowaste and vegetable waste compost use in agriculture can allow for the partial substitution of mineral fertilizer N and K. Following the repeated compost application in high rates, however, potential salinity or sodicity problems may rise.