Reusing urine and coffee processing wastewater as a nutrient source: Effect on soil characteristics at optimum cabbage yield

Abstract

Treatment and application of wastewater as a plant nutrient source is one of the waste management approaches currently used. This study attempted to investigate the effect of the application of human urine and coffee processing wastewater (UCPWW) on selected soil characteristics and compared it with rainwater and synthetic fertilizer in a completely randomized design. One-way analysis of variance (ANOVA) for difference and principal component analysis for correlation was employed. It was found that the soil organic carbon (SOC) and available phosphorus after production in a 1:2 ratio of UCPWW was significantly varied from the values before production and the soil treated with synthetic fertilizer (F=24.01, p=0.001; F=49.03, p=0.001, respectively). No significant difference was observed on micro-nutrients and the cation exchange capacity, but on some of the exchangeable cations: Na+(F=15.27, p=0.001) and Mg2+ (F=12.99, p=0.001) of 1:2 ratio application. The soil salinity was significantly increased and varied from other treatments: Na+ (F=11.88, p=0.04), Cl−(F=17.24, p=0.001), and total salinity (EC) (F=11.88, p=0.003), and significantly correlated with SOC and nutrients. The exchangeable sodium percentage (ESP), saturated electrical conductivity (ECe), and pH values for single round cultivation indicated no effects of sodicity, saline-sodicity, and salinity. However, the effect for repeated applications and cultivations, and mechanism of minimizing the salinity by the substrate should be studied before large-scale application.