Moisture in the soil profile with water applications using pulse drip irrigation

ABSTRACT The wet bulb, as a result of local application of irrigation water, is the soil volume that presents higher water content in relation to the surrounding soil. Due to increased moisture in the soil, successive irrigation events tend to form bigger wet bulbs and superficial water accumulation area (AWSS). The objective was to verify the distribution of water in the soil profile, with intermittent application of water, considering the hypothesis that antecedent soil water content modifies the wet bulb characteristics after water pulse application, and to evaluate the effect of increasing AWSS on the lateral dimensions of the bulb. The water applications were performed using 1, 2 and 4 pulses in the flows of 4 and 8 L h-1, totalizing six treatments, which were carried out in four replications for each treatment. The evaluations of AWSS were performed with the continuous application of water at the mentioned flow rates. The results indicate increasing AWSS does not affect the wet bulb, differences in the distribution of soil water are visible only in the first moments after last pulse application. It was concluded water tends to distribute in the soil regardless of the amount of irrigation pulses and pulse irrigation tends to result in similar distribution of moisture inside the wet bulb in relation to continuous irrigation.