Influência de diferentes lâminas de irrigação na produção de sorgo forrageiro

Abstract

The availability of pasture during the course of the entire year is very important for the development of any animal species, as well as maintaining its quality. During the spring-summer period the quality of rangelands decays due to irregular rainfall, requiring the cultivation of irrigated cultivated pastures. Thus, irrigation in spring-summer cultivated pastures, it is a great support technique so that it reaches the pasture supply target for the animals during the fault period of rainfall. In this context, the sorghum is characterized a suitable culture to be implemented by adapting to this time of year and the massive supply produced, however, requiring adequate water availability so that the maximum potential is reached. Thus, the aim of this study was to evaluate the growth and spring-summer pasture production planted with sorghum, under different irrigation levels, these being 0, 61, 65, 77, 100 and 136% of the reference evapotranspiration (ETo) in a block design at random, in order to determine the proper blade to reach the point of greatest efficiency of water use by the quantity and quality of forage dry matter produced at conditions of Santiago-RS in four cuts made at 50, 80, 110 and 140 days after sowing (DAS). We evaluated: plant height, stalk height, stalk diameter, leaf area index, number of stems per square meter, dry matter produced in each of the cuts, total dry mass and efficiency of water use. The different irrigation influenced in all evaluations performed for some of the DAS evaluated, with the depth of 100% of ETo the best results. Therefore, the sprinkler irrigation for sorghum crop is an alternative to the increased production, making it a possibility to meet periods of food shortage of native pasture, providing large supply of food for the animals.