Modelagem fuzzy do acúmulo de matéria seca e das variáveis nutricionais de coberturas vegetais de preparo para sistema plantio direto em resposta à diferentes doses de nitrogênio
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Data
2019-01-14
Autores
Góes, Bruno César
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Universidade Estadual Paulista (Unesp)
Resumo
O Sistema Plantio Direto (SPD) tem como característica a ocupação permanente do terreno agrícola com culturas vegetais além da manutenção da palhada sob a superfície do solo. Entretanto, para eficácia do SPD, é necessário adotar culturas de coberturas adequadas com a região a ser implementado, levando-se em consideração fatores edafoclimáticos e tipos de solo, para que dessa forma, haja a formação e manutenção da palhada sobre a superfície do solo. O sorgo possui como principais características, à tolerância de período de seca, e alto volume de produção de matéria seca, importantes para adoção dos sistemas de sucessão de culturas. O milheto, além da alta resistência à períodos de estresse hídrico, possui alta concentração de produção de biomassa. A taxa de decomposição da cobertura vegetal é regulada pela relação Carbono e Nitrogênio (C/N) específico de cada cultura. Nesse contexto, o presente trabalho visou analisar com modelos matemáticos os efeitos do nitrogênio sobre as culturas, sorgo e milheto, com finalidade de posterior uso como coberturas vegetais, sob níveis diferentes de nitrogênio em relação às variáveis de produtividade de matéria seca, teor de Nitrogênio (N), Fósforo (P), Potássio (K), Cálcio (Ca), Magnésio (Mg), Enxofre (S) e Molibdênio (Mo) e acúmulo de N, P, K, Ca, Mg, S e Mo com elaboração do modelo fuzzy. Foi realizada a comparação entre os modelos fuzzy (gaussiano e triangular) e de regressão polinomial por meio de testes estatísticos de ajustes de modelos e determinação do coeficiente de determinação (R²) . Dessa forma, concluiu-se que o melhor rendimento para os teores dos nutrientes analisados fora apresentado pela cobertura vegetal de milheto, já por sua vez, a cobertura vegetal de sorgo, apresentou os melhores rendimentos sobre os acúmulos dos nutrientes, pois obteve a maior produtividade de matéria seca em relação ao milheto. Analiticamente, verificou-se os melhores parâmetros estatísticos para a modelagem fuzzy triangular em comparação ao modelo fuzzy gaussiano e regressão polinomial de grau dois. No entanto, em relação ao comportamento da curva das modelagens matemáticas, o modelo gaussiano mostrou-se mais condizente com a realidade dos fenômenos agronômicos, em grande parte devida a suavização da curva sobre o conjunto dos dados.
The Direct Planting System (DPS) has as a characteristic the permanent occupation of the agricultural land with plant crops besides the maintenance of the straw under the soil surface. However, for DPS efficacy, it is necessary to adopt adequate cover crops with the region to be implemented, taking into account edaphoclimatic factors and soil types, so that the formation and maintenance of the straw on the soil surface. Sorghum has as main characteristics, to the tolerance of drought period, and high volume of dry matter production, important for the adoption of crop succession systems. Millet, besides the high resistance to periods of water stress, has high concentration of biomass production. The rate of decomposition of the vegetal cover is regulated by the relation Carbon and Nitrogen (C/N) specific of each culture. In this context, the present work aimed to analyze with mathematical models the effects of nitrogen on crops, sorghum and millet, with the purpose of later use as plant cover, under different levels of nitrogen in relation to the variables of dry matter yield content, Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S) and Molybdenum (Mo) and accumulation of N, P, K, Ca, Mg, S and Mo with elaboration of the fuzzy model. The comparison between the fuzzy (gaussian and triangular) and polynomial regression models was carried out by means of statistical tests of model adjustments and determination of the coefficient of determination (R²) . Thus, it was concluded that the best yield for the nutrient contents analyzed was presented by the plant cover of millet, and in turn, the vegetative cover of sorghum, presented the best yields on the accumulation of nutrients, as it obtained the highest productivity of dry matter in relation to millet. Analytically, the best statistical parameters for triangular fuzzy modeling were verified in comparison to the gaussian fuzzy model and degree two polynomial regression. However, in relation to the behavior of the mathematical modeling curve, the Gaussian model proved to be more in keeping with the reality of agronomic phenomena, due in large part to the smoothing of the curve over the data set.
The Direct Planting System (DPS) has as a characteristic the permanent occupation of the agricultural land with plant crops besides the maintenance of the straw under the soil surface. However, for DPS efficacy, it is necessary to adopt adequate cover crops with the region to be implemented, taking into account edaphoclimatic factors and soil types, so that the formation and maintenance of the straw on the soil surface. Sorghum has as main characteristics, to the tolerance of drought period, and high volume of dry matter production, important for the adoption of crop succession systems. Millet, besides the high resistance to periods of water stress, has high concentration of biomass production. The rate of decomposition of the vegetal cover is regulated by the relation Carbon and Nitrogen (C/N) specific of each culture. In this context, the present work aimed to analyze with mathematical models the effects of nitrogen on crops, sorghum and millet, with the purpose of later use as plant cover, under different levels of nitrogen in relation to the variables of dry matter yield content, Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulfur (S) and Molybdenum (Mo) and accumulation of N, P, K, Ca, Mg, S and Mo with elaboration of the fuzzy model. The comparison between the fuzzy (gaussian and triangular) and polynomial regression models was carried out by means of statistical tests of model adjustments and determination of the coefficient of determination (R²) . Thus, it was concluded that the best yield for the nutrient contents analyzed was presented by the plant cover of millet, and in turn, the vegetative cover of sorghum, presented the best yields on the accumulation of nutrients, as it obtained the highest productivity of dry matter in relation to millet. Analytically, the best statistical parameters for triangular fuzzy modeling were verified in comparison to the gaussian fuzzy model and degree two polynomial regression. However, in relation to the behavior of the mathematical modeling curve, the Gaussian model proved to be more in keeping with the reality of agronomic phenomena, due in large part to the smoothing of the curve over the data set.
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Lógica fuzzy, Modelagem matemática, Cultura de cobertura, Sorgo, Milheto, Fuzzy logic, Mathematical modeling, Cover crop, Sorghum, Millet