Soil measurements

The SW content is measured either directly (by weighting) or indirectly (profile probe device or PR2). In direct methodology, the mass or volume of water is specifically measured, but in indirect methodology, another factor that is related to the water content is measured first. Then the SW content is estimated based thereupon. The PR2 device is manufactured in two models PR2/4 (with four sensors) and PR2/6 (with six sensors) to measure the SW content in the vertical section. In PR2/6, six sensors are installed on the 1 m bar that enters the soil, and it simultaneously measures the SW content at the depths of 10, 20, 30, 40, 60 and 100 cm. The sensor diameter of the machine is 25.4 mm and the special plastic pipes to be installed in the soil have a diameter of 28 mm. SW content was measured three to four times per week (pre- and post-irrigation)³² to the depth of root development at maximum stress times for all black gram treatments. In the present study, a PR2/6 device calibrated with water weight data was used and tubes were installed in the middle of each plot²¹.