How diversity of crop residues in long-term no-tillage systems affect chemical and microbiological soil properties

Abstract

Integrated systems of agriculture lead to better food and environmental quality, but these systems are complex and should be evaluated in long-term experiments. The objective of this study is to evaluate long-term NT systems with different histories, management and different quantity and quality of plant residues on chemical and microbiological soil properties. The NT systems are located in three experimental fields of Embrapa Cerrados, in the Cerrado region, with 26, 21 and 12 years of establishment. The NT systems were characterized for soil chemical and microbiological properties and for quantity and quality of crop residues. Soil properties studied were basal respiration (BR), microbial biomass carbon (MBC), total organic carbon (TOC), total nitrogen (TN) and microbial quotient (qMIC) in three depths from 0–30 cm layer. The systems with annual succession of soybean with maize intercropped with U. brizantha grazed or not in the off-season increased the quantity of crop residues (around 10.70 ton ha−1) and contributed more to the quality of the vegetal residues, in addition to increasing MBC (up to 716 mg kg-1 soil), TN (between 4 and 5 g kg-1 soil), TOC (35 to 40 g kg-1 soil) and qMIC (up to 1.83%), which indicates that this system promoted improvement in the quality of chemical and biological soil properties and contributed to carbon accumulation in the soil over a period of 26 years.