Initial Growth and Roots Development of Soybean as Function of Water Availability and Soil Bulk Density

Abstract

Soil compaction is preponderant in soil physical-hydric relationships, which in turn, exert direct effect on plant development. In this context, this work aimed to evaluate the initial development of shoot and roots of soybean plants (Glycine max (L.) Merril), cv. BMX Ícone, cultivated in different combinations of soil bulk densities and water availability. A greenhouse experiment was carried out at the EMBRAPA Lowland Experimental Station, Rio Grande do Sul, Brazil. Soybean plants were grown in seven levels of soil bulk density (1.4, 1.5, 1.6, 1.7, 1.8, 1.9 and 2.0 kg dm-3) coupled to two soil water tensions (10 and 50 kPa). Plant height and leaf area, as well as root volume, decreased when soybean was cultivated at 50 kPa, associated to soil bulk densities above 1.8 kg dm-3. Soybean crop showed to be most sensitive to water deficit than to soil compaction, and soil water tension around the field capacity (10 kPa) should be associated to soil bulk density lower than 1.8 kg dm-3 to allow adequate soybean crop development.