Sistema de plantio direto como prática de produção agrícola sustentável
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Universidade Federal de Viçosa
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O sistema de plantio direto (SPD) é uma ferramenta para se alcançar a sustentabilidade nas produções agrícolas mundiais. No Brasil, a adoção do SPD vem crescendo significativamente visando a coexistência entre manutenção da qualidade do solo e obtenção de rendimentos produtivos. O manejo de áreas agrícolas sob o sistema deve ser acompanhado rotineiramente e pesquisas são necessárias para entendimento de como os diversos fatores físicos, químicos e biológicos do solo são influenciados de maneira concomitante e isoladamente pela inserção no SPD. A associação desses fatores complexos permite menores perdas de solo, nutrientes e matéria orgânica do solo (MOS) e, portanto, permitem maior aporte de carbono (C) ao solo. Nesse sentido, o fracionamento da MOS em matéria orgânica associada aos minerais do solo (MOAM) e particulada (MOP) e a análise do C presente em cada uma delas é uma maneira de entender o desempenho do SPD na estocagem de C no solo. No Capítulo 1 foi realizado uma busca completa nas bases SciELO, Elsevier e Google Acadêmico no período de março de 2021 a janeiro de 2023. Foi possível avaliar a evolução histórica do SPD; contextualizar o sistema por meio de atributos físicos, químicos e biológicos do solo; avaliar a relação entre o SPD e as plantas de cobertura utilizadas, a presença de pragas, doenças e plantas daninhas, a conservação do solo e da água, o balanço de gases de efeito estufa e, por fim, considerar o papel deste sistema conservacionista como ferramenta de marketing sustentável. Concluiu-se que o SPD é um sistema dinâmico e a complexidade de seus efeitos pode resultar em aumento, redução ou neutralidade nos atributos dos agroecossistemas. Para o experimento do Capítulo 2 foi utilizada uma área experimental da Fundação MT, em Itiquira, MT, implantada no ano de 2008, onde os tratamentos foram dispostos em delineamento experimental de blocos casualizados com quatro repetições. Os tratamentos foram constituídos de oito sistemas de cultivo (plantio convencional e sistemas de plantio direto com diferentes plantas de cobertura - crotalária, milheto e braquiária). Em 2020, amostras de solo nas camadas de 0-5, 5-10, 10-20 e 20-40 cm foram coletadas e o carbono total (C-TOTAL) e a MOAM foram determinados. O C da matéria orgânica particulada (MOP) foi obtido por diferença entre C-TOTAL e C-MOAM. Adicionalmente, foi estimado o estoque de C e o déficit de saturação de C no solo (DSC). Ao longo das 12 safras foi determinada a massa de matéria seca disposta sobre a área. Os tratamentos sob SPD favoreceram os estoques de C na MOAM, MOP e total. Em SPD houve maior acúmulo de C via parte aérea com uso de plantas de cobertura ocasionando em redução do DSC. Concluiu-se que o SPD no Cerrado é capaz de incrementar C no solo por meio do aumento de input do elemento via biomassa vegetal, redução da perturbação do solo e diversificação e rotação de culturas graníferas e de cobertura, práticas que favorecem a permanência do C-MOAM no solo e viabilizam a rotatividade equilibrada do C-MOP. Palavras-chave: Agricultura integrada. Conservação do solo. Sistemas de cultivo.
The no-tillage system (NTS) is a tool to achieve sustainability in the world agricultural production. In Brazil, the adoption of NTS has been significantly growing, aiming the coexistence between maintaining of the soil quality and obtaining of the productive yields. The management of agricultural areas under the system must be routinely monitored and researches are needed to understand how the different physical, chemical and biological factors of the soil are influenced concomitantly and separately by the insertion in the NTS. The association of these complex factors allows lower soil losses, nutrients and soil organic matter (SOM) and, therefore, allows a higher contribution of carbon (C) to the soil. In this sense, the fractionation of SOM into mineral-associated organic matter (MAOM) and particulate (POM) and the C analysis present in each of them is a way of understanding the performance of NTS in the storage of C in the soil. In the Chapter 1, was carried out a complete search in the SciELO, Elsevier and Google Scholar databases from March 2021 to January 2023. It was possible to assess the historical evolution of the NTS; contextualize the system through soil physical, chemical and biological attributes; evaluate the relationship between the NTS and the cover crops used, the presence of pests, diseases and weeds, the soil and water conservation, the balance of greenhouse gases and, finally, consider the role of this conservationist system as a sustainable marketing tool. It was conclude that the NTS is a dynamic system and the complexity of its effects can result in an increase, reduction or neutrality in the agroecosystems attributes. For the experiment in the Chapter 2, an experimental area of Fundação MT, in Itiquira, MT, implemented in 2008, was used, where the treatments were arranged in an experimental design of randomized blocks with four replications. The treatments consisted of eight cropping systems (conventional tillage and no-tillage systems with different cover crops - crotalaria, millet and brachiaria). In 2020, soil samples in the 0-5, 5-10, 10-20 and 20-40 cm depth layers were collected and the C-TOTAL and MAOM were determined. The C of the POM was obtained by the difference between C-TOTAL and C-MAOM. Additionally, C stock and soil C saturation deficit (CSD) were estimated. Over the 12 harvests, productivity and dry matter mass disposed over the area were determined. The treatments under NTS favored the C stocks in MAOM, POM and total. In NT, there was a higher accumulation of C via shoots with the use of cover crops, leading to a reduction in CSD. It was conclude that NT in the Cerrado is able to increase C in the soil by increasing the input of the element via plant biomass, reduction of soil disturbance and diversifying and rotation of grain and cover crops, practices that lead to the permanence of C-MAOM in the soil and enable the balanced rotation of the C- POM. Keywords: Integrated agriculture. Soil conservation. Cultivation systems. SUMÁRIO
The no-tillage system (NTS) is a tool to achieve sustainability in the world agricultural production. In Brazil, the adoption of NTS has been significantly growing, aiming the coexistence between maintaining of the soil quality and obtaining of the productive yields. The management of agricultural areas under the system must be routinely monitored and researches are needed to understand how the different physical, chemical and biological factors of the soil are influenced concomitantly and separately by the insertion in the NTS. The association of these complex factors allows lower soil losses, nutrients and soil organic matter (SOM) and, therefore, allows a higher contribution of carbon (C) to the soil. In this sense, the fractionation of SOM into mineral-associated organic matter (MAOM) and particulate (POM) and the C analysis present in each of them is a way of understanding the performance of NTS in the storage of C in the soil. In the Chapter 1, was carried out a complete search in the SciELO, Elsevier and Google Scholar databases from March 2021 to January 2023. It was possible to assess the historical evolution of the NTS; contextualize the system through soil physical, chemical and biological attributes; evaluate the relationship between the NTS and the cover crops used, the presence of pests, diseases and weeds, the soil and water conservation, the balance of greenhouse gases and, finally, consider the role of this conservationist system as a sustainable marketing tool. It was conclude that the NTS is a dynamic system and the complexity of its effects can result in an increase, reduction or neutrality in the agroecosystems attributes. For the experiment in the Chapter 2, an experimental area of Fundação MT, in Itiquira, MT, implemented in 2008, was used, where the treatments were arranged in an experimental design of randomized blocks with four replications. The treatments consisted of eight cropping systems (conventional tillage and no-tillage systems with different cover crops - crotalaria, millet and brachiaria). In 2020, soil samples in the 0-5, 5-10, 10-20 and 20-40 cm depth layers were collected and the C-TOTAL and MAOM were determined. The C of the POM was obtained by the difference between C-TOTAL and C-MAOM. Additionally, C stock and soil C saturation deficit (CSD) were estimated. Over the 12 harvests, productivity and dry matter mass disposed over the area were determined. The treatments under NTS favored the C stocks in MAOM, POM and total. In NT, there was a higher accumulation of C via shoots with the use of cover crops, leading to a reduction in CSD. It was conclude that NT in the Cerrado is able to increase C in the soil by increasing the input of the element via plant biomass, reduction of soil disturbance and diversifying and rotation of grain and cover crops, practices that lead to the permanence of C-MAOM in the soil and enable the balanced rotation of the C- POM. Keywords: Integrated agriculture. Soil conservation. Cultivation systems. SUMÁRIO
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ARAUJO, Izabella Marani Martins. Sistema de plantio direto como prática de produção agrícola sustentável. 2023. 144 f. Dissertação (Mestrado em Fitotecnia) - Universidade Federal de Viçosa, Viçosa. 2023.