Umidade do solo em cultivo de feijão com refletômetro de conteúdo de água sob variações de cobertura do solo e de irrigação.

Abstract

The objective of this study is to show volumetric (m3 m-3) soil moisture changes using observations made by automatic sensors water content reflectometer with and without calibration for a bean crop seeded under 3 different soil cover situations: So (bare soil), S1 (vegetal straw), S2 (plastic bags) and different water regimens in a factorial experiment. The observed distributions indicated the need of calibration with the local soil data. Volumetric soil moisture changed between 18.1%-18.5%, 16.5%-17.2% and 16.4%-18.8% for So, S1 and S2 situations, respectively. The changes in moisture amplitudes were 6.4%, 4.9% and 5.8%respectively. During the period of water stress, the suppression of watering for 8 days (between days 37 to 51) showed a smaller moisture amplitude for straw S1 (0.7%) than of situations S2 (1.9%) and So (7.4%) thus indications that the soil covers favor a less water loss during the period that irrigation ceased.