The Effect of water depths and moisture depletion on vertical and horizontal distribution for moisture in soil profile under surface drip irrigation system

Abstract

A Field experiment was conducted at one of the fields of College of Agriculture- University of Baghdad in which, it is 20 km west-north of the capital Baghdad where it is Located Longitudes ʺ41.76 ′12 440 East and latitudes330 ′19 4.8ʺ during the summer season/2016. To study the effect of water depths and moisture depletion on vertical and horizontal distribution for moisture under surface drip irrigation system for the soil profile.The study was included two factors: first is the water depths in three levels; Full water depth 100% the under water depth, 75% and the over water depth 125%. Which the second factor is the moisture depletion, for two levels 25% depletion and at 50% depletion. The treatments were distributed as a Factorial experimental according to Randomized Complete Block Design. The surface drip irrigation system (GR emitters: discharge 4 L hr-1). Was obtained for irrigate the experiment land during the study at operation pressure 50 kpa. The moisture distribution was estimated for the study treatments for the spaces 0.10, 0.20, 0.30 and 0.40m, horizontally and at depths of 0.20, 0.40 and 0.60m vertically from the emitter during the three stages of tomato growth (vegetables ,Flowering and holding Fruits and maturity).The results showed that there is on increased of the moisture content of the drip source (emitter) and a decrease while being away from it vertically and horizontally for all study treatments, and the best moisture content was obtained at full water, while the low moisture content was obtained while adding over water depth. The advance of crop growth stages increased the moisture content. In addition, the increase of moisture depletion percentage from 25% to 50%, decrease the values of moisture content in to soil profile.