Soil organic matter fractions in an Oxisol under tillage systems and winter cover crops for 26 years in the Brazilian subtropics

IF 1.2 4区农林科学 Q2 AGRICULTURE, MULTIDISCIPLINARY

Bragantia Pub Date : 2022-01-01 DOI:10.1590/1678-4499.20210352

Caroline Amadori, P. C. Conceição, C. A. Casali, L.B.S. Canalli, A. Calegari, J. Dieckow

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引用次数: 2

Abstract

: The improvement of carbon (C) accumulation in soils has been one of the main purposes of the conservation systems in agricultural production. This study aimed to assess the long-term effect of conventional tillage (CT) and no-tillage (NT) combined with winter cover crops, black oat and oilseed radish, and fallow on C accumulation and stabilization in a very clayey Oxisol in Southern Brazil. Soil samples were collected in the 0-0.05, 0.05-0.10 and 0.10-0.20 m layers of a 26-year-old experiment. Distribution of size-class aggregates, C stock in aggregates, total C stock, and C stocks in the physical fractions, free particulate organic matter (free-POM), occluded particulate organic matter (occluded-POM) and mineral-associated organic matter (min-OM) were assessed. NT had a higher percentage of macroaggregates and C stock in this size-class, and also higher C stock in bulk soil, free-POM and occluded-POM fractions than CT in 0-0.05 m (Tukey’s test p < 0.05), due to higher input of biomass and minimum soil mobilization in NT. Oat and radish had higher C stock in macroaggregates than fallow in 0.05-0.10 m (Tukey’s test p < 0.05). Radish had the highest C stock in the free-POM (0-0.05 m). Fallow decreased the stabilization of macroaggregates and C accumulation in free-POM, due to the lower C input from aboveground biomass over the years. In conclusion, NT after 26 years improved C accumulation and stabilization, mainly in the superficial layer and in POM fractions, and winter cover crops favored the formation and stability of macroaggregates.

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巴西亚热带地区26年耕作制度和冬季覆盖作物下Oxisol土壤有机质组分

改善土壤碳(C)积累已成为农业生产中保护系统的主要目的之一。本研究旨在评估常规耕作(CT)和免耕作(NT)配合冬季覆盖作物、黑燕麦和油籽萝卜以及休耕对巴西南部极粘土Oxisol中碳积累和稳定的长期影响。选取0 ~ 0.05 m、0.05 ~ 0.10 m和0.10 ~ 0.20 m三层土壤样品，历时26年。评估了粒径级团聚体、团聚体中的碳储量、总碳储量、物理组分中的碳储量、自由颗粒有机质(free- pom)、封闭颗粒有机质(occluded- pom)和矿物伴生有机质(min-OM)的分布。在0 ~ 0.05 m范围内，由于NT的生物量投入较大，土壤动员最小，因此NT的大团聚体和C储量比CT高(Tukey’s检验p < 0.05)，且块状土壤、游离pom和闭聚pom组分的C储量也高于CT (Tukey’s检验p < 0.05)。在0.05 ~ 0.10 m范围内，燕麦和萝卜的大团聚体C储量高于休耕(Tukey’s检验p < 0.05)。在自由pom (0-0.05 m)中，萝卜的碳储量最高，由于多年来地上生物量的碳输入减少，休耕降低了自由pom中大团聚体的稳定性和碳积累。综上所述，26 a后氮肥处理促进了土壤中碳的积累和稳定，主要表现在表层和POM组分中，冬盖作物有利于大团聚体的形成和稳定。

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来源期刊

Bragantia AGRICULTURE, MULTIDISCIPLINARY-

CiteScore

2.40

自引率

8.30%

发文量

审稿时长

4 weeks

期刊介绍： Bragantia é uma revista de ciências agronômicas editada pelo Instituto Agronômico da Agência Paulista de Tecnologia dos Agronegócios, da Secretaria de Agricultura e Abastecimento do Estado de São Paulo, com o objetivo de publicar trabalhos científicos originais que contribuam para o desenvolvimento das ciências agronômicas. A revista é publicada desde 1941, tornando-se semestral em 1984, quadrimestral em 2001 e trimestral em 2005. É filiada à Associação Brasileira de Editores Científicos (ABEC).