Microbial diversity and effects on soil attributes, soil carbon stock, and crop yield in no-tillage system

Abstract

Plant species that integrate No-Tillage system (NT) may alter the abundance and diversity of soil microorganisms over time. The microorganisms, on the other hand, can exert great influence on soil organic carbon dynamics, with effects on soil chemical and physical attributes, as well as on soil carbon stock and, consequently, on soil productive potential. Soil C dynamics depend on specific environmental conditions, which suggests a regionalized assessment of the soil's ability to store C in the long term under different uses and management. The objective of the present work is to evaluate the effect of crop sequences on abundance and microbial diversity and their influence on soil attributes and soil carbon stock under long term NT system. The experiment has been conducted since 2001. The treatments are composed of three sequences of summer crops: Corn Monoculture (CC), Soybean Monoculture (SS) and Soybean/Corn rotation (SC) with soybean and corn intercropping year by year; and seven intercropping crops: corn, sunflower, oilseed radish, pearl millet, pigeon pea, grain sorghum and sunn hemp, totaling 21 treatments with three replicates. Soil chemical and physical attributes, carbon stock, soil abundance and diversity of microorganisms, activities of the ²-glucosidase, arylsulfatase and acid phosphatase enzymes, and quality and quantity of plant residues left on the soil surface by the crops will be evaluated after 20 years of NT system establishment. Therefore,this study, coupled with data from previous years, seeks to estimate the contribution of different crop sequences in the microbial community and the annual contribution of C to the soil, seeking a relationship between microorganisms and C sequestration and their effects on soil attributes and productivity of cultures under NT. (AU)