Changes in quantity and quality of SOM in whole soils and fractions affected by times of adoption of no-till system: evidence from natural 13C abundance and solid-state 13C NMR spectroscopy

Abstract

Soil organic matter (SOM) is one of the main factors that contributes for high soil quality and for crop yield increases in the tropics and subtropics. However, soil management can influence its content and composition. No-till (NT) is a well-established production system in Brazil that promotes C sequestration, but there are few studies on the SOM dynamics over time in this system and on the stability of the newly C sequestered. Thus, the objective of this project is to provide a more detailed understanding of the effects of this soil management system on SOM dynamics (i.e., quantity and quality), evaluating the stability of the newly sequestered C and inferring about its resilience in an occasional soil management change. In order to evaluate the allocation of the newly C sequestered in the SOM fractions (with different levels of stability) the natural abundance of 13C will be applied. To identify the alteration of SOM composition the solid-state 13C NMR spectroscopy will be applied in the whole soil and SOM fractions. Finally, we intend to calibrate and validate a model for the rapid prediction of C content and composition in the soils studied. (AU)