Maize growth and root organic acid exudation in response to water extract of compost application

Abstract

Water extract of compost (WEC) can be used to develop eco-friendly fertilizers and presents plant biostimulant effects. The aim of this study was to evaluate WEC bioactivity effects on maize growth and root organic acid exudation. Maize plants were cultivated 24 days in nutrient solution with WEC addition at the concentrations of 0, 2, 5, 15, 40, and 75 mg L−1 of C. The SPAD index, shoot dry matter (SDM), root dry matter (RDM), and nutrient accumulation in maize shoot were measured, and organic acid root exudate was determined. WEC application increased maize growth in 30%, compared to control plants. Furthermore, SPAD index, N, K, S, and Mn shoot accumulation; K and Mn uptake efficiency; and S, Fe, and Mn translocation efficiency increased over WEC concentrations. Root organic acid exudation of isocitric, oxalic, and tartaric increase about 100%, citric and malic about 200%, and succinic was more than four times higher, in relation to maize plants not treated with WEC. WEC augmented maize growth and stimulated root organic acid exudation. The optimum WEC concentration was about 40 mg L−1 of C in nutrient solution.