Perdas de solo, nutrientes e água por erosão e o subfator CiII em Argissolo e Latossolo com resíduos vegetais de cana-de-açúcar
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Data
2019-04-22
Autores
Gomes, Mayara Germana dos Santos
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Universidade Estadual Paulista (Unesp)
Resumo
A perda do solo quando ocasionada pela água da chuva resulta em impactos negativos como a degradação do solo. O fator cobertura e manejo do solo (Fator C) é aquele que mais facilmente técnicos e agricultores podem modificar, com o intuito de reduzir a erosão em entressulcos com a adição de resíduos vegetais na superfície do solo. O presente trabalho teve os seguintes objetivos: 1) avaliar a eficácia do uso de resíduos de palha de cana-de-açúcar em diferentes proporções no controle das perdas de solo, água, matéria orgânica (MO) e nutrientes; 2) propor modelos para estimar o subfator CiII relativo ao manejo com resíduos mantidos em superfície; 3) estimar o custo da erosão associados com as perdas de nutrientes do solo. O experimento foi realizado em duas áreas experimentais. A área 1 está localizada no município de Guariba - SP num Latossolo (LV) enquanto a área 2 está localizada no município de Tabapuã - SP em um Argissolo (PV). Para estimar as perdas de solo, água e nutrientes por erosão, aplicou-se chuva artificial, em parcelas experimentais, com 0 (CS0), 50% (CS50) e 100% (CS100) de cobertura sobre a superfície do solo. Cada parcela tinha a dimensão de 0,50 m de largura e 1,00 m de comprimento (0,5 m2). A intensidade média da chuva foi 60 mm h-1, durante 60 minutos. Os tratamentos CS100 propiciaram redução significativa nas perdas de solo (90%), água (88%), MO (97%) e nutrientes como P (97%), K (96%), Ca e Mg (98%), para ambos solos. O aumento da cobertura do solo nos tratamentos reduz os custos das perdas de nutrientes por erosão quando expressos em termos de P2O5 (R$ 2,09 ha-1), KCl (R$ 4,30 ha-1) e corretivo do solo CaMg (CO3)2 (R$ 1,70 ha-1). As taxas de infiltração de água foram maiores nas parcelas com CS50 e CS100. Recomenda-se o uso da equação CiII = e-2,917 CS/100, no LV e PV estudados, nas estimativas indiretas do subfator cobertura e manejo do solo para a cultura da cana-de-açúcar, em áreas com colheita mecanizada.
Soil loss when caused by rainwater results in negative impacts such as soil degradation. The soil cover and management factor (Factor C) is the one that technicians and farmers can most easily modify in order to reduce interrill erosion with the addition of vegetal residues on the soil surface. The present work had the following objectives: 1) to evaluate the effectiveness of the use of sugarcane straw residues in different proportions in the control of soil losses, water, organic matter (OM) and nutrients; 2) to propose models for estimating the sub-factor CiII concerning the management with residues kept on the surface; 3) estimate the cost of erosion associated with soil nutrient losses. The experiment was carried out in two experimental areas. Area 1 is located in the municipality of Guariba - SP in a Latosol (LV) while area 2 is located in the municipality of Tabapuã - SP in an Argisol (PV). To estimate soil, water and nutrient losses by erosion, artificial rainfall was applied in experimental plots with 0 (CS0), 50% (CS50) and 100% (CS100) covering on the soil surface. Each plot was 0.50 m wide and 1.00 m long (0.5 m2). The average rainfall intensity was 60 mm h-1 for 60 minutes. CS100 treatments provided significant reduction in soil losses (90%), water (88%), MO (97%) and nutrients such as P (97%), K (96%), Ca and Mg both alone. The increase in soil cover in the treatments reduces the costs of erosion losses when expressed in terms of P2O5 (R$ 2.09 ha-1), KCl (R$ 4.30 ha-1) and soil remediation Ca Mg (CO3)2 (R$ 1.70 ha-1). Water infiltration rates were higher in the plots with CS50 and CS100. It is recommended to use the CiII = e-2,917 CS / 100, in the LV and PV studied, in the indirect estimates of the sub-soil cover and soil management for the sugarcane crop, in areas with mechanized harvesting.
Soil loss when caused by rainwater results in negative impacts such as soil degradation. The soil cover and management factor (Factor C) is the one that technicians and farmers can most easily modify in order to reduce interrill erosion with the addition of vegetal residues on the soil surface. The present work had the following objectives: 1) to evaluate the effectiveness of the use of sugarcane straw residues in different proportions in the control of soil losses, water, organic matter (OM) and nutrients; 2) to propose models for estimating the sub-factor CiII concerning the management with residues kept on the surface; 3) estimate the cost of erosion associated with soil nutrient losses. The experiment was carried out in two experimental areas. Area 1 is located in the municipality of Guariba - SP in a Latosol (LV) while area 2 is located in the municipality of Tabapuã - SP in an Argisol (PV). To estimate soil, water and nutrient losses by erosion, artificial rainfall was applied in experimental plots with 0 (CS0), 50% (CS50) and 100% (CS100) covering on the soil surface. Each plot was 0.50 m wide and 1.00 m long (0.5 m2). The average rainfall intensity was 60 mm h-1 for 60 minutes. CS100 treatments provided significant reduction in soil losses (90%), water (88%), MO (97%) and nutrients such as P (97%), K (96%), Ca and Mg both alone. The increase in soil cover in the treatments reduces the costs of erosion losses when expressed in terms of P2O5 (R$ 2.09 ha-1), KCl (R$ 4.30 ha-1) and soil remediation Ca Mg (CO3)2 (R$ 1.70 ha-1). Water infiltration rates were higher in the plots with CS50 and CS100. It is recommended to use the CiII = e-2,917 CS / 100, in the LV and PV studied, in the indirect estimates of the sub-soil cover and soil management for the sugarcane crop, in areas with mechanized harvesting.
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Palavras-chave
Erosão em entressulcos, Fator cobertura e manejo, Rainfall simulation, Interrill erosion, Coverage and management factor, Chuva simulada