Chemical and biological properties as affected by no-tillage and conventional tillage systems in an irrigated Haploxeroll of Central Chile

Abstract

Soil management practices may change the soil properties. The magnitude of the change varies according to the soil property, the climate, and the type and time of implementation of a particular management system. The aim of this study was to evaluate the effects of no-tillage (NT) on the chemical and biological properties of an Entic Haploxeroll in Central Chile. Soil organic carbon (SOC), microbial biomass and associated indicators qCO2 , qMic, qMin, available N, P and K, pH, electrical conductivity (EC), and crop yield were determined in a field experiment having a wheat (Triticum turgidum L.)–maize (Zea mays L.) crop rotation. The change in soil chemical properties was further evaluated using a greenhouse bioassay in which ryegrass (Lolium perenne L.) was grown in soil samples extracted at 0–2, 2–5, and 5–15 cm depth. After nine years SOC in the NT treatment was 29.7 Mg ha 1 compared to 24.8 Mg ha 1 of CT, resulting in 4.98 Mg ha 1 C gain. The NT therefore resulted in an average annual sequestration of 0.55 Mg C ha 1 yr 1 in the upper 15 cm soil. The soil organic C stored under NT was mainly accumulated in the top 2-cm of soil. The biological indicators showed a greater biological soil quality under NT than under CT. Soil organic C was positively associated with available N, P, and K, but negatively with soil pH. The ryegrass bioassay yielded higher biomass in NT than CT. An improvement in the soil chemical quality of the NT soil was considered to be the main reason for this result. The maize yield under NT had the tendency to improve in time as compared to CT. Wheat, however, had lower yield under NT. It was concluded that NT increased C sequestration and SOC improving the chemical and biological properties of this soil