Intervalo hídrico ótimo no monitoramento da compactação e da qualidade física de um latossolo vermelho cultivado com soja
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Data
2007-12-01
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Sociedade Brasileira de Ciência do Solo
Resumo
A qualidade física do solo é essencial ao crescimento das plantas e à sustentabilidade dos sistemas agrícolas. O objetivo deste estudo foi avaliar a eficiência do intervalo hídrico ótimo (IHO) no monitoramento da compactação e qualidade física do solo para soja em cultivo de sequeiro e irrigado. O experimento foi realizado em Latossolo Vermelho eutroférrico (21 ° 14 ' 53S; 48 ° 17 ' 20W; 540 m de altitude). O delineamento experimental foi inteiramente casualizado em esquema fatorial 6 x 2, com quatro repetições. Os tratamentos de compactação foram: T1 = sem compactação; T2 = 1 passada de trator de 4 t; T3 = 1; T4 = 2; T5 = 4; e T6 = 6 passadas de um trator de 11 t, no mesmo local. Foi semeada a soja (Glycine max (L.) Merrill), cultivar IAC Foscarim 31. Foram coletadas amostras indeformadas de solo nas camadas de 3-6, 8-11, 15-18 e 22-25 cm, para determinação dos atributos físicos. Na colheita, foi avaliada a produtividade de soja em microparcela de 3,37 m². No cultivo de soja sequeiro e irrigado, a produtividade diminui a partir da resistência à penetração (RP) de 1,30 e 1,64 MPa e da densidade do solo (Ds) de 1,26 e 1,29 kg dm-3, com perdas de 19,15 e 11,71 % no maior nível de compactação (RP = 2,84 MPa; Ds = 1,45 kg dm-3), respectivamente. O IHO foi reduzido pela RP até atingir a Dsc(IHO = 0) de 1,33 e 1,38 kg dm-3, no cultivo de soja sequeiro e irrigado. O IHO é adequado no monitoramento da compactação e da qualidade física do solo para soja, quando sua aplicação é realizada com base no valor de resistência à penetração limitante e no valor de densidade crítica do solo (IHO = 0). A soja em cultivo irrigado tolera maior compactação.
Soil physical quality is essential for plant growth and sustainable agricultural systems. This study aimed to evaluate the efficiency of the least limiting water range (LLWR) to monitor soil compaction and soil physical quality for soybean, without and with irrigation. The study was carried out in an clayer Red Latosol (Oxisol) (21 ° 14 ' 53S; 48 ° 17 ' 20W; 540 m asl). The experiment was entirely randomized, in a 6 x 2 factorial scheme, with four repetitions. The compaction treatments were: T1 = without compaction; T2 = 1 pass of a 4 t tractor; T3 = 1, T4 = 2, T5 = 4 and T6 = 6 passes of an 11 t tractor over the same track. Soybean (Glycine max (L.) Merrill), cultivar IAC Foscarim 31 was planted. Undisturbed soil samples were collected in the layers 3-6, 8-11, 15-18 and 22-25 cm to determine soil physical attributes. In the harvest soybean yield was evaluated in 3.37 m² microplots. Soybean yield, cultivated without and with irrigation, dropped when penetration resistance increased from 1.30 to 1.64 MPa and bulk density from 1.26 to 1.29 kg dm-3, with yield losses of 19.15 and 11.71% at the highest compaction level (RP = 2.84 MPa; Ds = 1.45 kg dm-3), respectively. The LLWR was reduced by RP until reaching critical soil bulk density (Dsc(IHO = 0)) of 1.33 and 1.38 kg dm-3, in non-irrigated and irrigated soybean. LLWR is an adequate indicator of soil compaction and physical quality for soybean when applied based on the critical bulk density value Dsc(LLWR = 0). Irrigated soybean is more tolerant to compaction.
Soil physical quality is essential for plant growth and sustainable agricultural systems. This study aimed to evaluate the efficiency of the least limiting water range (LLWR) to monitor soil compaction and soil physical quality for soybean, without and with irrigation. The study was carried out in an clayer Red Latosol (Oxisol) (21 ° 14 ' 53S; 48 ° 17 ' 20W; 540 m asl). The experiment was entirely randomized, in a 6 x 2 factorial scheme, with four repetitions. The compaction treatments were: T1 = without compaction; T2 = 1 pass of a 4 t tractor; T3 = 1, T4 = 2, T5 = 4 and T6 = 6 passes of an 11 t tractor over the same track. Soybean (Glycine max (L.) Merrill), cultivar IAC Foscarim 31 was planted. Undisturbed soil samples were collected in the layers 3-6, 8-11, 15-18 and 22-25 cm to determine soil physical attributes. In the harvest soybean yield was evaluated in 3.37 m² microplots. Soybean yield, cultivated without and with irrigation, dropped when penetration resistance increased from 1.30 to 1.64 MPa and bulk density from 1.26 to 1.29 kg dm-3, with yield losses of 19.15 and 11.71% at the highest compaction level (RP = 2.84 MPa; Ds = 1.45 kg dm-3), respectively. The LLWR was reduced by RP until reaching critical soil bulk density (Dsc(IHO = 0)) of 1.33 and 1.38 kg dm-3, in non-irrigated and irrigated soybean. LLWR is an adequate indicator of soil compaction and physical quality for soybean when applied based on the critical bulk density value Dsc(LLWR = 0). Irrigated soybean is more tolerant to compaction.
Descrição
Palavras-chave
Glycine max (L.) Merrill, machinery traffic, Soil quality, Water content, tráfego de máquinas, Solos - Qualidade, Conteúdo de água, Glycine max (L.) Merrill
Como citar
Revista Brasileira de Ciência do Solo. Sociedade Brasileira de Ciência do Solo, v. 31, n. 6, p. 1223-1232, 2007.