Department of Agricultural Engineering, Indian Institute of Technology, Kharagpur, West Bengal
*Present address: Water Management Project, Mahatma Phule Krishi Vidyapeeth, Rahuri, Maharashtra
**Present address: Water and Soil Management Institute, Aurangabad, Maharashtra
Water loss through large simulated shrinkage cracks in black (clay) soil in relation to soil moisture content was assessed under controlled conditions and predicted using a simple theory of water vapour flux. The evaporative flux was influenced by crack dimensions and change in potential evaporative demand. The decrease in evaporation rate with tinie was slower in the relatively wet range and faster in the dry range. The slope of the cumulative evaporation versus time curve decreased with increase in the crack depth. Observed water loss rates were greater than the predicted water vapour flux density by a factor of 2.45. About 32% of the water loss could be accounted from below 30 cm depth in the shrinkage crack.
Simulated shrinkage crack, water vapour transfer, water flux
