Indicadores de qualidade de argissolo submetido à escarificação em área mecanizada de cana-de-açúcar
Data
2018-07-11
Autores
Pinheiro, Daniel Pereira
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A escarificação somente na linha de plantio é um tipo de preparo mínimo do solo que vem sendo utilizado na reforma de canaviais, e o seu impacto sobre a qualidade física do solo necessita ser avaliado. O objetivo neste trabalho foi avaliar a qualidade física de Argissolo, submetido à escarificação para o plantio de cana-de-açúcar. Os tratamentos avaliados foram: escarificação do solo somente na linha de plantio (ELP) e escarificação em área total (EAT). O experimento foi realizado no município de Monte Alto, SP, próximos as coordenadas 21º 15’ S e 48º 25’ W, altitude média 735 m. Foram avaliadas quatro épocas de amostragem: após o preparo do solo com escarificação, após o plantio da cana-de-açúcar, seis meses após o plantio e após a colheita mecanizada da cana-de-açúcar. Amostras de solo foram coletadas nas camadas de 0,00-0,10 m, 0,10-0,20 m, 0,20-0,40 m e 0,40-0,60 m de profundidade em dois locais de amostragem (linha e entrelinha de plantio). Determinaram-se os teores de areia, silte e argila, e os atributos físicos: densidade do solo (Ds), resistência mecânica à penetração (RP), macroporosidade (MaP), microporosidade (MiP). A partir do conjunto de dados obtidos, realizou-se uma análise fatorial multivariada com extração dos fatores pelo método da análise de componentes principais. Dois fatores foram extraídos e explicaram 76% da variação total. O primeiro fator, responsável por 44 % da variância total pôde ser interpretado como a resposta da formação de microporosidade do solo influenciada pela natureza textural, uma vez que, as variáveis relevantes neste fator foram MiP, areia e argila. Esse fator representou o indicador intrínseco do solo. O segundo fator, responsável por 32 % da variância remanescente pôde ser interpretado como a resposta do processo de alteração na relação massa-volume do solo, uma vez que, as variáveis relevantes nesse fator foram MaP, Ds e RP. Esse fator remanescente, representou o indicador do manejo do solo. Após a extração dos fatores, com base nos valores de escores fatoriais obtidos, determinou-se um índice de qualidade física do solo (IQFS) que, conjuntamente com os dois fatores extraídos, auxiliaram na avaliação da qualidade física do solo. Após o preparo da área, as linhas de plantio submetidas à escarificação apresentaram qualidade física melhor que as entrelinhas de cultivo, em função do maior volume de poros e menor RP e Ds. Porém, o efeito benéfico da escarificação do solo não foi persistente em função do fenômeno da reconsolidação do solo, desaparecendo logo após o plantio e estendendo-se após a colheita da cana-de-açúcar, cujas linhas e entrelinhas de cultivo apresentaram qualidade física do solo semelhante para as duas áreas avaliadas.
Soil chiseling conducted only in the planting row is a type of minimal-disturbance soil management practice to prepare fields for planting of sugarcane plantations, and its impact on soil physical quality needs to be evaluated through agricultural experimentation. The objective of this study was to evaluate the physical quality of an Ultisol that was submitted to chiseling as part of sugarcane plantation management. The treatments consisted of soil chiseling only in the planting row (CPR), and chiseling in the total area of the soil of the plantation (CTA). The experiment was carried in Monte Alto, SP, near the coordinates 21º 15 'S and 48º 25' W, average altitude 735 m. Four sampling periods were evaluated. Four periods were evaluated: after soil chiseling, after sugarcane planting, six months after planting, and after mechanized sugarcane harvest. Soil samples were collected within and between planting rows in depths 0.00-0.10, 0.10-0.20, 0.20-0.40, and 0.40-0.60 m. Soil texture was determined along with the following soil physical indicators: bulk density (BD), mechanical penetration resistance (PR), total porosity (TP), macroporosity (MaP), microporosity (MiP). A multivariate factorial analysis was conducted with factor extraction done by the method of principal components analysis. Two extracted factors explained 76% of the total variation. The first factor responsible for 44% of the total variance could be interpreted as the response of soil microporosity formation influenced by the textural nature, since the relevant variables in this factor were MiP, sand and clay. This factor represented the soil intrinsic indicator. The second factor, responsible for 32% of the remaining variance, could be interpreted as the response of the alteration process in the soil mass-volume relationship, since the relevant variables in this factor were MaP, Ds and RP. This remaining factor represented the indicator of soil management.. After factor extraction and using the factorial scores, the index of soil physical quality was determined (SQI), which, together with two factor, aided in the evaluation of soil physical quality. After soil preparation, the planting rows that were submitted to chiseling had better soil physical quality than did the area between the rows that did not receive chiseling in site preparation due to greater pore volume and lower PR and BD. However, the beneficial effect of chiseling did not persist due to subsequent soil reconsolidation, and disappeared soon after the planting of sugarcane, and remained this way up to the post-harvest period wherein the areas within (CPR) and between (CTA) the planting rows had equal soil physical quality.
Soil chiseling conducted only in the planting row is a type of minimal-disturbance soil management practice to prepare fields for planting of sugarcane plantations, and its impact on soil physical quality needs to be evaluated through agricultural experimentation. The objective of this study was to evaluate the physical quality of an Ultisol that was submitted to chiseling as part of sugarcane plantation management. The treatments consisted of soil chiseling only in the planting row (CPR), and chiseling in the total area of the soil of the plantation (CTA). The experiment was carried in Monte Alto, SP, near the coordinates 21º 15 'S and 48º 25' W, average altitude 735 m. Four sampling periods were evaluated. Four periods were evaluated: after soil chiseling, after sugarcane planting, six months after planting, and after mechanized sugarcane harvest. Soil samples were collected within and between planting rows in depths 0.00-0.10, 0.10-0.20, 0.20-0.40, and 0.40-0.60 m. Soil texture was determined along with the following soil physical indicators: bulk density (BD), mechanical penetration resistance (PR), total porosity (TP), macroporosity (MaP), microporosity (MiP). A multivariate factorial analysis was conducted with factor extraction done by the method of principal components analysis. Two extracted factors explained 76% of the total variation. The first factor responsible for 44% of the total variance could be interpreted as the response of soil microporosity formation influenced by the textural nature, since the relevant variables in this factor were MiP, sand and clay. This factor represented the soil intrinsic indicator. The second factor, responsible for 32% of the remaining variance, could be interpreted as the response of the alteration process in the soil mass-volume relationship, since the relevant variables in this factor were MaP, Ds and RP. This remaining factor represented the indicator of soil management.. After factor extraction and using the factorial scores, the index of soil physical quality was determined (SQI), which, together with two factor, aided in the evaluation of soil physical quality. After soil preparation, the planting rows that were submitted to chiseling had better soil physical quality than did the area between the rows that did not receive chiseling in site preparation due to greater pore volume and lower PR and BD. However, the beneficial effect of chiseling did not persist due to subsequent soil reconsolidation, and disappeared soon after the planting of sugarcane, and remained this way up to the post-harvest period wherein the areas within (CPR) and between (CTA) the planting rows had equal soil physical quality.
Descrição
Palavras-chave
Saccharum spp, Saccharum spp, Agricultura, Preparo do solo, Agriculture, Soil tillage