Matéria orgânica em um Latossolo submetido a diferentes sistemas de produção de milho
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Data
2003-12-01
Autores
Souza, W. J. O. [UNESP]
Melo, W. J. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Ciência do Solo
Resumo
Com objetivo de avaliar o efeito de sistemas de produção sobre a dinâmica do carbono no solo e nas frações da matéria orgânica, durante seis anos, em Jaboticabal (SP), foram testados diferentes tratamentos, a saber: semeadura convencional de milho com pousio no inverno (C-Mi-P), plantio direto de milho e pousio no inverno (D-Mi-P), convencional de milho em rotação com soja e pousio no inverno (C-Mi-P-So), plantio direto de milho em rotação com soja e pousio no inverno (D-Mi-P-So) e plantio direto de milho com uso de Mucuna aterrina (mucuna preta), Cajanus cajan (feijão guandu) e Crotalaria juncea no inverno (D-Mi-Mu, D-Mi-Gu e D-Mi-Cr) em delineamento de blocos ao acaso e parcelas subdivididas. Após 60 dias da emergência das plântulas, coletaram-se amostras de solo a diferentes profundidades (0-0,05, 0,05-0,10 e 0,10-0,20 m). Avaliaram-se nas amostras os teores de C orgânico (CO) e C total nas frações: matérias húmicas (MH), solúvel em água (SA), ácido fúlvico (AF), ácido húmico (AH) e humina (HN) com dados expressos em base de terra seca em estufa (TSE). O uso do sistema plantio direto com pousio e o cultivo de leguminosas no inverno (mucuna preta e feijão guandu) foram os que apresentaram maiores valores de CO e C-HN na camada de 0-0,05 m. O tratamento C-Mi-P-So mostrou o maior valor de C-SA na camada de 0,05-0,10 m. Quanto aos teores de C-MH, os tratamentos C-Mi-P-So e D-Mi-P-So foram os que apresentaram os maiores valores nas camadas superficiais. O plantio direto de milho em monocultura e sucessão com leguminosas (mucuna preta e feijão guandu) parecem ter favorecido dois processos: migração de AF para as camadas mais profundas, reduzindo os valores de MH nas camadas superficiais do solo, e interconversões de AF em AH mais rápidas.
A long-term field trial was carried out in the Jaboticabal county, São Paulo State. with the objective of estimating production system effects on the soil organic carbon and soil organic matter fractions. The tested treatments were corn under conventional sowing in the summer and no-tillage in the winter (C-Mi-P), maize under direct sowing in the summer and no-tillage in the winter (D-Mi-P), maize under direct sowing in the summer, Mucuna aterrina as green manure in the winter (D-Mi-Mu), maize under direct sowing in the summer, Cajanus cajan as green manure in the winter (D-Mi-Gu), conventional maize in summer crop rotation with soybean and no-tillage in the winters (C-Mi-P-So), maize under direct sowing in crop rotation with soybean and no tillage in the winters (D-Mi-P-So), and maize under direct sowing in the summer, and Crotalaria juncea as green manure in the winter (D-Mi-Cr). The experimental design consisted of randomized blocks with four replicates. 60 days after plant emergence, soil samples were collected (at depths of 0-0.05, 0.05-0.10, and 0.10-0.20 m). Total organic carbon and organic carbon in the organic matter fractions (humic matter, water-soluble carbon/ solúvel em água, fulvic acid, humic acid, and humin) were determinated in the oven-dried soil samples. Direct sowing with no tillage or legume crops in the winter (Mucuna aterrina or Cajanus cajan) led to the highest total organic-C and organic-C in the humin fraction. The C-Mi-P-So treatment caused the highest water soluble carbon value in the 0.05-0.10 m layer. The treatments C-Mi-P-So and D-Mi-P-So presented the highest values for organic-C in the humic matter fraction of the soil organic matters. Maize monoculture in direct sowing system, followed by no tillage or legume crops in the winter (Mucuna aterrina or Cajanus cajan) apparently supported two processes: migration of the humic acid organic-C to deeper layers, reducing the humic material values in the superficial layers and a faster transformation of fulvic acid organic-C fraction to humic acid organic-C.
A long-term field trial was carried out in the Jaboticabal county, São Paulo State. with the objective of estimating production system effects on the soil organic carbon and soil organic matter fractions. The tested treatments were corn under conventional sowing in the summer and no-tillage in the winter (C-Mi-P), maize under direct sowing in the summer and no-tillage in the winter (D-Mi-P), maize under direct sowing in the summer, Mucuna aterrina as green manure in the winter (D-Mi-Mu), maize under direct sowing in the summer, Cajanus cajan as green manure in the winter (D-Mi-Gu), conventional maize in summer crop rotation with soybean and no-tillage in the winters (C-Mi-P-So), maize under direct sowing in crop rotation with soybean and no tillage in the winters (D-Mi-P-So), and maize under direct sowing in the summer, and Crotalaria juncea as green manure in the winter (D-Mi-Cr). The experimental design consisted of randomized blocks with four replicates. 60 days after plant emergence, soil samples were collected (at depths of 0-0.05, 0.05-0.10, and 0.10-0.20 m). Total organic carbon and organic carbon in the organic matter fractions (humic matter, water-soluble carbon/ solúvel em água, fulvic acid, humic acid, and humin) were determinated in the oven-dried soil samples. Direct sowing with no tillage or legume crops in the winter (Mucuna aterrina or Cajanus cajan) led to the highest total organic-C and organic-C in the humin fraction. The C-Mi-P-So treatment caused the highest water soluble carbon value in the 0.05-0.10 m layer. The treatments C-Mi-P-So and D-Mi-P-So presented the highest values for organic-C in the humic matter fraction of the soil organic matters. Maize monoculture in direct sowing system, followed by no tillage or legume crops in the winter (Mucuna aterrina or Cajanus cajan) apparently supported two processes: migration of the humic acid organic-C to deeper layers, reducing the humic material values in the superficial layers and a faster transformation of fulvic acid organic-C fraction to humic acid organic-C.
Descrição
Palavras-chave
plantio direto, adubação verde, carbono, ácido fúlvico, ácido húmico, humina, direct sowing, green manure, carbon, fulvic acid, umic acid, humin
Como citar
Revista Brasileira de Ciência do Solo. Sociedade Brasileira de Ciência do Solo, v. 27, n. 6, p. 1113-1122, 2003.