Evaluation of Soil Wetting Patterns in Clay Loam Soil under Drip Irrigation

Maximum agricultural water use efficiency is important owing to decrease of availability of water for agricultural field. Drip irrigation is considered so far as the most efficient irrigation systems. Knowledge of dimension of the soil wetted volume is one of the main factors in determining the spacing of drippers. It is important in the design and management of the irrigation system. The present study was conducted at the Instructional Farm, Faculty of Agricultural Engineering, Bidhan Chandra Krishi Viswavidyalaya, Moahanpur, Nadia, West Bengal to examine the vertical (Z) and horizontal (W) water front advance within the soil profile at the dripper in a clay loam soil. Same volume of water (50 litre) was applied at the rate of 2.3 and 4.9 l/h at each irrigation. By observing the soil on the tips of the auger, the depth of wetting was determined and noted it down for different points on the line of the wetted area. It was found that there is little variation in the theoretical width and depth with the actual width and depth of wetting of the soil in case of 4.9 lph discharge rate. For the given discharge rate, the inaccuracy was less for the wetted depth than the wetted diameter. In the instance of the 2.3 lph discharge rate, however, there was a lot more fluctuation. This variation might be resulted from some experimental errors due to surrounding disturbances and climatic variation.