Kitchen waste compost increases lettuce growth and shows residual effect on soil fertility

Abstract

Composting is an important tool for transforming organic waste into useful products for agriculture. However, the characterization of the compost and its capacity to stimulate crop growth are necessary to ensure sanitary quality and process efficiency. In this study, the objectives were characterize and evaluate a kitchen waste compost produced in static piles as a stimulant to lettuce growth. The residual effect of compost on soil fertility was also studied. A randomized block design was used, with 3 replications of compost doses equivalent to 0, 30, 60 and 90 t ha^-1. The compost presented chemical characteristics that allow their agricultural use according to Brazilian regulations, but a high electrical conductivity (EC) value was detected. The absence of E. coli indicated that the process was efficient to guarantee the elimination of the pathogenic contaminant. Although compost has reduced net CO₂ assimilation, stomatal conductance and leaf transpiration in plants, consistent increases in shoot and root dry mass, as well as in shoot projection were noticed, with the dose of 90 t ha^-1. Residual effect in soil fertility was also confirmed. The kitchen waste compost obtained from static piles is a safe product that enables the recycling of nutrients, spurring the development of lettuce and resulting in a residual effect on soil fertility.