Organic Matter Fractions and Carbon Management Index in Oxisol Under Integrated Agricultural Production Systems

Abstract

This work aimed to evaluate the oxidizable and chemical fractions of organic matter and the carbon management index in different integrated agricultural production systems, hay production and native forest areas in an Oxisol. Nine areas with different management systems were evaluated being six managements of the combination between different oat density (40 and 60 kg ha^-1) and grazing frequencies (0, 1 and 2) in autumn-winter and soybean succession in spring-summer, one with natural reseeding ryegrass and forage turnip in autumn-winter and soybean succession in spring-summer and two reference areas. In each soil management systems were collected soil samples composite in the 0-5, 5-10 and 10-20 cm layers and determined the Total Organic Carbon (TOC), humic substances (Fulvic Acids - FA, Humic Acids - HA and humin - HUM), the carbon in the oxidizable fractions (F1, F2, F3 and F4) and Carbon Management Index (CMI). Were observed that chemical, oxidizable fractions and CMI, do not have significant differences between with the various managements each other. For TOC, HA, HUM, F1, F3, F4 and CMI, the managements did not differ from the reference areas indicating maintenance of soil carbon.