Efeito de variáveis meteorológicas no crescimento e produtividade de cultivares de capim na zona da mata alagoana.

Abstract

Understanding the water-soil-plant-atmosphere relationships and their effects on forage plants is fundamental to optimize the pasture productivity. In this sense, the objective of this study was to evaluate the influence of agrometeorological variables on growth, yield and supporter capacity of grass cultivars. The experiment was done at the Center of Agricultural Sciences of the Federal University of Alagoas, from April to August 2018. The treatments were six grass cultivars: Capim Elefante cv. BRS Kurumi, Brachiaria decumbens cv. Basilisk, Hybrid Brachiaria cv. Mulatto II, Brachiaria brizantha cv. Xaraés, Panicum maximum cv. Massai and Panicum maximum cv. Mombasa The experimental design was randomized blocks with five replications. The variables analyzed were: agrometeorological (rain, evapotranspiration, air temperature and photosynthetically active radiation), water balance, leaf area index (IAF), vegetative canopy height (CH), light intercept index, green and dry matter yield, light extinction coefficient, water productivity and supporter capacity of grass cultivars. Rainfall from April to august was (611,9 mm), higher than the reference evapotranspiration (376,3 mm), but due to the irregular distribution of rainfall in that period, there was water excess (288,8 mm), and hidric deficit (34,4 mm). The intercepted radiation was 103,6 MJ m-2, the LAI and CH were 2,9 and 64,9 cm. green matter (GM) and dry matter (DM) yield were 6.695,0 and 1.367,1 t ha-1, respectively. The average water productivity was 0,24 kg of GM per cubic meter of water and maximum supporter capacity was 6,5 animal units per hectare. The cultivars that produced the most green and dry matter were BRS Kurumi and Massai, respectively. The cultivars Mombasa and Massai were the most responsive to water and with the highest carrying capacity.