Respostas fisiológicas da soja submetida ao estresse hídrico e compactação do solo

Abstract

Water stress is one of the main causes of variation of the potential productivity of soybean. Soil compaction is also highly correlated with the water availability of the soil, which is determinant in the growth and development of the soybean, contributing to productivity. However, it can be achieved with the adoption of deficit irrigation that reduces the transpiration rate, contributing to the increase of water use efficiency without compromising the regulation of gas exchange in the photosynthetic process and for phytomass production in compacted soil at intermediate levels. Thus, this study aimed a) to evaluate the water stress and phytomass accumulation of soybean in a compacted soil with irrigation deficit, b) to evaluate the effect of water deficit on the physiological parameters, behavioral growth analysis and soybean performance in compacted soil. The results of the first experiment demonstrated that the stomatal conductance, transpiration, intercellular CO2 concentration and the net photosynthesis rate were not altered by the specific mass of the soil. However, dry shoot and root phytomass were altered by soil compaction and / or by the daily blade of water in the soil to provide lower number of dry vegetable phytomass on the 4.0 mm depth. The results of the second experiment indicated that the daily depths of 4.0 and 5.0 mm provided the best results of water use efficiency and in the instant efficiency of water use, but not in dry phytomass gain. Soil compaction at intermediate levels is not detrimental to the development of the aerial part and in the growth of the root system.