Lâminas de irrigação e adubações silicatada, nitrogenada e potássica na cultura do milho verde na região de Iguatu- CE

• Ano de defesa: 2020
• Autor(a) principal: Fernandes, Chrislene Nojosa Dias
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Zea mays L.; Déficit hídrico; Adubação; Water deficit; Fertilization
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/56026

In the northeastern semiarid, the cultivation of green maize is a typical practice of family farming, with social, economic and food importance. This culture combined with the irrigation technique allows cultivation also during the dry period. Thus, estimating the correct water depth becomes decisive for successful crop productivity. In addition, studies indicate that the exogenous application of silicon has resulted in benefits to vegetables, conferring greater tolerance to stresses, which may allow the reduction of the water layer applied. Throughout the crop cycle, nitrogen (N) and potassium (K) are absorbed in greater quantities and fit the fertigation technique perfectly, due to the high water solubility and mobility in the soil. However, the interaction between different doses of essential mineral nutrients can reinforce, decrease, mask, or even revert to the responses of vegetables to a certain nutrient, which makes it imperative to define the interactive effects of simultaneous applications of these nutrients under conditions fertigated for the culture in question. n this context, the general objective of this research was to study the effects of interactions between irrigation blades versus silicon doses, applied via foliar; and doses of nitrogen versus potassium doses, fertigated, in the corn crop, aiming at the production of green ears of the hybrid AG1051. For this, two field experiments were conducted, in the experimental area belonging to the Federal Institute of Education, Science and Technology of Ceará (IFCE), campus Iguatu, Ceará, from August to November 2017, In experiment I, slides were evaluated irrigation and silicon doses, the blades corresponding to: 50; 75; 100; 125 and 150% of the potential evapotranspiration of the culture, ETc (mm day-1), with silicon applied via leaf corresponding to 0; 50; 100 and 200% of the recommended dose of Si, for corn, by the manufacturer of the source used. In experiment II, nitrogen and potassium doses, applied by fertigation, corresponding to 0; 50; 100 and 200% of the recommended dose of N (170 kg ha-1) and K (40 kg ha-1). In both, the growth variables analyzed were: plant height, stem diameter, leaf dry mass, stem and total at 15; 30; 45; 60 and 75 days after sowing; and the productive ones: the diameter, length and mass of the ear without straw, the mass of the ear with straw and productivity. The data obtained with the growth variables were subjected to analysis of variance, using the F test, according to the randomized block design in a subdivided plot scheme, where the times of assessment of the referred variables constituted the sub-parcels. The data obtained with the productive variables were subjected to analysis of variance, using the F test, and analyzed according to the randomized block design in a split plot scheme. In the case of proving the significant effects on the interactions between the factors studied, the data of the variables were plotted on response surfaces. For cases in which a significant effect for the factor was found in isolation, the data of the variables were studied through regression analysis. In experiment I, the irrigation depths and the different seasons significantly influenced the growth variables, with increasing linear responses for both factors studied, with the exception of the stem diameter variable, which responded quadratically to the factors studied. The irrigation depths positively influenced the production of green corn, where the irrigation depth of 600 mm referring to 150% of ETc, provided the maximization of the responses of the analyzed productive variables. The foliar application of silicon in the studied doses was not able to provide favorable effects for the cultivation of green corn. In experiment II, nitrogen doses and different seasons significantly influenced the vegetative growth variables studied with increasing linear responses for both factors studied, with the best values obtained with the highest N dose evaluated, 340 kg ha-1, and at 75 days after sowing, with the exception of the stem diameter that behaved quadratically for the season factor, with the maximum value at 52 days after sowing. The nitrogen doses positively influenced the production of the green corn crop, with the highest dose evaluated providing the highest values for the productive variables analyzed. Potassium doses did not influence the variables studied.