Micrometeorologia em ambiente protegido para cultivares de soja sob diferentes lâminas de irrigação

Abstract

Soy is a raw material for a variety of products, destined for food, animal feed, biodiesel, among others, under a growing annual demand. However, such activity is only possible under specific meteorological conditions, and alterations outside the optimum conditions for the crop, with respect to temperature, air humidity, soil water availability, radiation and day length, directly influence growth and crop production. In this context, the objective of this study was to evaluate growth, until flowering, of three soybean cultivars, BRSMG 820 RR, BRSMG 850 RR and BRS Favorita RR, under different soil water stresses and specific micrometeorological conditions. The experiment was conducted in a conventional greenhouse located in the experimental area of the Engineering Department of UFLA, located in the city of Lavras-MG, between April and June 2016, under a completely randomized design (CRD) and factorial scheme (5x3), with five replicates, five soil water stress levels (7, 12, 25, 40 and 60 kPa) and three different cultivars. In each vessel, filled with soil classified as Oxiso l, soil moisture sensors were installed at a depth of 25 cm to monitor soil water tension and conduct irrigation management. Soil temperature was monitored using “T” type thermocouples. For the monitoring of air temperature, relative humidity and radiation, a weather station was installed in the center of the greenhouse. The correction of the photoperiod was artificial lighting. The results showed that the treatment corresponding to 7 kPa provided the best soil moisture conditions for good development, moisture at 80% of field capacity (Ucc), and tensions 25, 40 and 60 kPa, moisture about 50% Ucc for the studied soil, are not recommended. The cultivar BRSMG 820 RR had the greatest height and leaf area index, and differentiated statistically from the others. No significant differences were found in shoot and root dry mass among the analyzed cultivars.