Biochar and poultry manure effects on selected soil physical and chemical properties and maize (Zea Mays) in a dry environment

Abstract

Poultry manure (PM) is an inexpensive source of fertilizer but it decomposes quickly and releases carbon and greenhouse gases. Biochar (BC) could be an alternative source of carbon to improve soil quality and reduce greenhouse gas emission. This study investigated the effect of co-application of BC and PM on selected soil physical and chemical properties and performance of maize. A field experiment was conducted at the University of Venda experimental farm during 2015/2016 and 2016/2017 seasons. The experiment was a 4 x 3 factorial arrangement consisting of four rates of BC (0, 5, 10 and 20 t ha-1) and three rates of PM (0, 2, and 4 t ha-1) in a RCBD arrangement replicated three times. Maize was planted in both seasons. After harvest, soil bulk density was determined at four soil depths (0-5, 5-10, 10-15, and 15-20 cm), while aggregate stability and selected soil chemical properties were determined at two soil depths (0-15 cm and 15-30 cm). Data were subjected to ANOVA using Genstat 17th edition. The least significant difference was used to compare the treatment means at P < 0.05. Soil aggregate stability, organic carbon, Ca2+, Mg2+, K+, maize dry matter and maize grain yield increased with increasing rates of BC and PM application at 0 - 15 cm depth in both seasons. The combination of BC at 20 t ha-1 and PM at 4 t ha-1 significantly (P < 0.05) decreased soil bulk density at 5 - 10 cm depth but increased soil available P and total N at the two depths in both seasons. The results of this study suggested that BC and PM improved soil ability to retain and supply nutrients through improved soil aggregate stability and reduced bulk density thereby improving maize dry matter and grain yield. Combining BC with PM proved to enhance the ability of soil to function by improving selected soil physical and chemical properties thereby improving maize dry matter and grain yield.