Plant residues are considered the primarily resource for soil organic carbon (SOC). The amounts and quality of plant residue are important controlling factors for the SOC sequestration. The SOC can be divided into two major pools based on particle size: particulate C pool (> 53 µm) (POC) and the C mineral-associated pools (< 53 µm) (MOC). The POC is composed mainly of plant, root and fungal hyphae residues at varying stages of decomposition. POC can respond rapidly to changes in soil C input due to soil and/or crop management. For this reason, POC pool has been considered an early indicator of the effects of cropping systems on soil quality. The MOC pool is a relative stable pool of SOC. It is formed predominantly by humic substances (humin, humic acid and fulvic acid). Those humic substances are partially resistant to microbial degradation, which preserve SOC depletion. Additionally, they have considerable contribution on SOC reactivity, which affect SOC quality. We performed a study to determine the impact of residues of 21 different crop sequences on POC and MOC pools, and on soil humic substance contents of an Oxisol under no-till. The study was conducted in Jaboticabal, SP, Brazil (21°14’ S; 48°17’ W; 550 m asl). The climate is classified as Koppen’s Aw (a tropical climate with a dry winter and the average temperature of the coldest month above 18 °C). The average annual rainfall is 1,425 mm, with an annual distribution peaking in the period of October-March. The average annual temperature is 22 °C, and the relative humidity is 70%. The experiment was conducted using a split-block design. Two sets of treatments were composed of t ... 전체 초록 보기