Irrigação por aspersão e produção de sementes de soja em solo de várzea

Abstract

The soybean crop in the southern half of Rio Grande do Sul is increasing annually and, therefore, this region is becoming a new agricultural frontier. However in this State, in most years, the frequency and intensity of rainfall during the development of soybeans are insufficient for that culture manifests its productive potential. The study subject was to evaluate sprinkler irrigation effect on soybean varieties performance and the physiological quality of seed produced on paddy soil. The field work was conducted at Embrapa Clima Temperado, while the seed quality evaluations were performed at the Laboratory Textbook of Seed Analysis, of Universidade Federal de Pelotas (LDAS / UFPel). The treatments consisted of sixteen soybean cultivars and two water regimes (irrigation throughout cycle and without irrigation), eight medium cycle cultivars and eight late-maturing cultivars, using randomized complete blocks with split plots and three replicates. The spray irrigation was performed using a linear movable. Irrigation was performed whenever the soil water sensors (Watermark type) when registered 40 kPa. During the experiment determinations were carried out at field level, such as height, height of the first pod insertion, stem diameter. After harvesting were conducted: seed yield, yield components and thousand seed weight. To evaluate the physiological quality tests were conducted germination, first count, accelerated aging, electrical conductivity and field emergence. Statistical analysis was performed using analysis of variance and hypothesis testing to verify the significance of main effects and interactions. For mean comparison test was used for the Scott-Knott 5% probability. The sprinkler irrigation promotes increase in soybean yield in cultivars of medium cycle and late-maturing cultivars. The numbers of pods and seeds per plant, and on the main stem increased due to irrigation. It also provides increases in physical and physiological quality through the thousand seed weight, germination, electric conductivity and field emergence. Irrigation increased cycle of soybean.