Níveis de Irrigação por gotejamento na cultura do milho na zona da mata alagoana

Abstract

In the zone of the alagoana forest the corn agricultural productivity is well below the potential of the cultivars currently available in the market and the main reason for this low yield is, mainly due to the irregularities of the winter rain, which even in the rainy season sometimes stays seven or more days followed without rain, affecting the development of the maize crop, which needs 380 to 550 mm, depending on the climatic conditions. This water deficiency can be supplied by irrigation to improve the development of the crop. Therefore, with the objective of analyze the development, growth and productivity of corn with different levels of irrigation, a field experiment was set up at the Agricultural Sciences Center of the Federal University of Alagoas (CECA/UFAL). The experimental design was randomized blocks,,in the subdivided plot scheme and the treatments were levels of irrigation and nitrogen fertilization. But in this work It was analyzed the effects of the irrigation levels. The decendial water balance was done by the method of THORNTWAITE & MATHER, (1957), with the meteorological data of rainfall (P) and reference evapotranspiration (ET0), provided by the Irrigation and Agrometeorology Laboratory (LAI) of the Federal University of Alagoas. The analyzed variables were: development (duration of the phenological phases), growth (based on vegetative canopy height, leaf area index, LAI) and agricultural productivity. During the corn crop production cycle there was an average water deficit of 60.8 mm, the mean maximum LAI (4.2) and the mean maximum vegetative canopy height (2.3 m) are observed at 60 and 75 days after planting, respectively. The average grain yield was 7.8 t ha-1 and the maximum physical 8.4 t ha-1 obtained with 498 mm irrigation.