The effect of Fire of Wheat Residues and Sawdust on Soil Water Repellency

Crop residue burning has been proved to have negative impacts on regional atmospheric environment, soil organic material, reduce soil fertility for long term and soil and water pollution. Therefore, the aim of this study is to investigate the effect of Burning the wheat residue and sawdust on the water repellency of soil. For this purpose, sampling was done of soil surface (0-15 cm) in the east of Ahvaz city in four treatments: sawdust, burned sawdust, wheat residue and burned wheat residue, with 3 replications in ratio of 5, 10 and 25 presents by weight. for measure soil water repellency, was used water drop penetration time (WDPT) method. Analysis of obtained data and mean comparisons were done with using SPSS software and drawing charts with Excel. The results showed that the average water drop penetration time into the soil was 116.33 seconds, the soil was placed in the strongly water repellent class. With the addition sawdust and wheat residues to the soil, were decreased the amount of water penetration into the soil. So that the (WDPT) time from 116.33 in blank treatment decreased to 62.67 and 47.67 second (respectively) in the 25% treatment. The water repellency class was changed from strongly to slightly water repellent. But burned sawdust and burned wheat residues were increased the amount of water penetration into the soil, so that the (WDPT) from 116.33 in blank treatment increased to 923 and 1008.33 second (respectively) in the 25% treatment.