Uso de remineralizadores, inoculantes e urochloa ruziziensis como condicionadores de solo na sucessão soja-milho
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Data
2021-11-19
Autores
Oliveira, Celismar Ferreira de
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Universidade Estadual Paulista (Unesp)
Resumo
O uso de remineralizadores é uma técnica antiga e consiste basicamente no uso de rochas finamente trituradas como fontes de liberação lenta de diversos nutrientes, podendo assim atuar como fertilizantes naturais. Assim, o uso desses materiais como forma única de manejo da fertilidade do solo não parece ser muito efetivo, de maneira que o posicionamento de remineralizadores como fornecedores de nutrientes deve ser realizado juntamente com agentes do biointemperismo, como microrganismos e plantas de cobertura. Diante da realidade de preço dos fertilizantes e a relevância que estes insumos têm para a agricultura brasileira, faz-se necessário uma melhor compreensão da efetividade do uso de remineralizadores nos sistemas de produção. Assim, o objetivo deste trabalho foi comparar o desempenho agronômico e melhorias nas condições físicas do solo no sistema de produção soja-milho em consórcio com Urochloa ruziziensis em resposta ao uso de remineralizadores naturais como fonolito e fosfato natural com fertilizantes de alta solubilidade (KCl e MAP). Um experimento de campo foi conduzido em Latossolo Vermelho distroférrico, na Fazenda Lageado na área experimental da Universidade Estadual Paulista (UNESP), na cidade de Botucatu-SP, nas safras 2019/2020 e 2020/2021, em sistema de sucessão soja-milho. O trabalho avaliou tanto a produtividade das culturas como também o impacto do manejo com remineralizadores, plantas de cobertura e microrganismos na estruturação do solo. Na adubação, utilizou-se uma testemunha absoluta e mais dois tratamentos no sistema de semeadura direta em sucessão de culturas: a) fósforo solúvel (60 Kg ha-1 P2O5) + potássio solúvel (60 Kg ha-1 K2O) e b) fosfato Natural (28% P2O5) + Fonolito (8% de K2O). Ao final de duas safras foram avaliadas a produtividade e as propriedades físicas do solo como: densidade aparente (Ds); resistência à penetração (RP); porosidade total (Pt); macroporosidade (Map); microporosidade (Mip); capacidade de campo (CC); diâmetro médio ponderado dos agregados (DMP); diâmetro médio geométrico (DMG); agregados com diâmetro maior que 2 mm (agg>2 mm); índice de estabilidade de agregados (IEA); carbono orgânico total (COT); carbono orgânico particulado (Cop) e carbono orgânico associado aos minerais (Coam). O delineamento utilizado foi em blocos inteiramente casualizados (DBC) com quatro repetições. Adotou-se o teste de comparações múltiplas de Scott-Knott (p < 0,05). Os tratamentos com uso de remineralizadores de baixa solubilidade, microrganismos e U. ruziziensis, ainda que não tenham apresentado melhorias significativas na estruturação do solo, demonstraram que o uso desses insumos de baixa solubilidade quando combinado com microrganismos, é uma técnica agronômica que pode conferir produtividades próximas àquelas alcançadas por fertilizantes industrializados de alta solubilidade, ao mesmo tempo em que pode proporcionar maior estabilidade ao sistema produtivo. Todavia, o uso dessas fontes naturais como uma técnica isolada, parece não apresentar efeito satisfatório. Assim, ter um ambiente produtivo com uma microbiota diversificada ou lançar mão da adição de inoculantes, pode ser uma alternativa viável para incrementar e/ou acelerar o biointemperismo dos minerais e liberação dos nutrientes às plantas.
The use of remineralizers is an old technique and basically consists of using finely crushed rocks as a source of slow release of several nutrients, thus being able to act as natural fertilizers. On the other hand, the use of these materials as a unique form of soil fertility management does not seem to be very effective, so the positioning of remineralizers as nutrient suppliers must be carried out together with bioweather agents such as microorganisms and cover crops. Taking into account the reality of fertilizer prices and the relevance that these inputs have for Brazilian agriculture, a better understanding of the effectiveness of the use of remineralizers in production systems is necessary. Thus, the objective of this work was to compare the agronomic performance and improvements in soil physical conditions in the soybean-corn production system intercropped with Urochloa ruziziensis in response to the use of natural remineralizers such as phonolite and rock phosphate with high solubility fertilizers (KCl and MAP). A field experiment was conducted in a dystroferric Red Latosol at the Lageado Farm owned by the Universidade Estadual Paulista (UNESP), in the city of Botucatu-SP, in Crops 2019/2020 and 2020/2021, in a soybean-corn succession system, to evaluate not only crop productivity, but also the impact of management with remineralizers, cover crops and microorganisms on soil structuring. As for fertilization, an absolute control and two treatments were used in the no-tillage system in crop succession: a) soluble phosphorus (60 Kg ha-1 P2O5) + soluble potassium (60 Kg ha-1 K2O) and b) phosphate Natural (28% P2O5) + Phonolite (8% K2O). At the end of two crops, productivity and soil physical properties were evaluated, such as: bulk density (Ds); resistance to penetration (RP); total porosity (Pt); macroporosity (Map); microporosity (Mip); field capacity (CC); weighted mean diameter of aggregates (DMP); geometric mean diameter (DMG); aggregates with a diameter greater than 2 mm (agg>2 mm); aggregate stability index (IEA); total organic carbon (TOC); particulate organic carbon (Cop) and organic carbon associated with minerals (Coam). The design used was a completely randomized blocks (DBC) with four replications. Statistical analyzes were performed using the R programming language in the Rstudio environment. Before the analysis of variance, the ANOVA assumptions were checked and the Scott-Knott test for multiple comparisons was adopted (p < 0.05). The treatments with the use of low solubility remineralizers, microorganisms and U. ruziziensis, although they have not shown significant improvements in soil structuring, demonstrated that the use of these low solubility inputs when combined with microorganisms is an agronomic technique that can confer yields close to those achieved by industrialized fertilizers with high solubility, while at the same time providing greater stability to the production system. However, the use of these natural sources as an isolated technique does not seem to have a satisfactory effect. Thus, having a productive environment with a diversified microbiota, or making use of the addition of inoculants, can be a viable alternative to increase and/or accelerate the biowetting of minerals and release of nutrients to plants. In general, the use of remineralizers has the potential to be part of the fertilization system, however, further studies are needed to better explain the dynamics of nutrients and their impact on chemistry, microbiota and soil structuring.
The use of remineralizers is an old technique and basically consists of using finely crushed rocks as a source of slow release of several nutrients, thus being able to act as natural fertilizers. On the other hand, the use of these materials as a unique form of soil fertility management does not seem to be very effective, so the positioning of remineralizers as nutrient suppliers must be carried out together with bioweather agents such as microorganisms and cover crops. Taking into account the reality of fertilizer prices and the relevance that these inputs have for Brazilian agriculture, a better understanding of the effectiveness of the use of remineralizers in production systems is necessary. Thus, the objective of this work was to compare the agronomic performance and improvements in soil physical conditions in the soybean-corn production system intercropped with Urochloa ruziziensis in response to the use of natural remineralizers such as phonolite and rock phosphate with high solubility fertilizers (KCl and MAP). A field experiment was conducted in a dystroferric Red Latosol at the Lageado Farm owned by the Universidade Estadual Paulista (UNESP), in the city of Botucatu-SP, in Crops 2019/2020 and 2020/2021, in a soybean-corn succession system, to evaluate not only crop productivity, but also the impact of management with remineralizers, cover crops and microorganisms on soil structuring. As for fertilization, an absolute control and two treatments were used in the no-tillage system in crop succession: a) soluble phosphorus (60 Kg ha-1 P2O5) + soluble potassium (60 Kg ha-1 K2O) and b) phosphate Natural (28% P2O5) + Phonolite (8% K2O). At the end of two crops, productivity and soil physical properties were evaluated, such as: bulk density (Ds); resistance to penetration (RP); total porosity (Pt); macroporosity (Map); microporosity (Mip); field capacity (CC); weighted mean diameter of aggregates (DMP); geometric mean diameter (DMG); aggregates with a diameter greater than 2 mm (agg>2 mm); aggregate stability index (IEA); total organic carbon (TOC); particulate organic carbon (Cop) and organic carbon associated with minerals (Coam). The design used was a completely randomized blocks (DBC) with four replications. Statistical analyzes were performed using the R programming language in the Rstudio environment. Before the analysis of variance, the ANOVA assumptions were checked and the Scott-Knott test for multiple comparisons was adopted (p < 0.05). The treatments with the use of low solubility remineralizers, microorganisms and U. ruziziensis, although they have not shown significant improvements in soil structuring, demonstrated that the use of these low solubility inputs when combined with microorganisms is an agronomic technique that can confer yields close to those achieved by industrialized fertilizers with high solubility, while at the same time providing greater stability to the production system. However, the use of these natural sources as an isolated technique does not seem to have a satisfactory effect. Thus, having a productive environment with a diversified microbiota, or making use of the addition of inoculants, can be a viable alternative to increase and/or accelerate the biowetting of minerals and release of nutrients to plants. In general, the use of remineralizers has the potential to be part of the fertilization system, however, further studies are needed to better explain the dynamics of nutrients and their impact on chemistry, microbiota and soil structuring.
Descrição
Palavras-chave
solubilização, rochagem, física do solo, remineralizadores, condicionadores de solo, sistema de produção, solubilization, rock dust, soil physics, soil remineralizers, soil conditioners, production system