Effects of organic and mineral amendments on mean-weight diameter of soil aggregates

Soil structure and aggregate stability affect soil erodibility. There is a necessity for increasing aggregate stability against erosive factors such as wind and water. This study conducted on surface soil samples (0-20cm) collected from agricultural land susceptible to erosion located in the south of Fars Province. The experimental design was CRD with 10 treatments of control plot (without addition of soil amendments)، pure gypsum، chopped wheat straw، animal manure، wheat straw and gypsum، animal manure and gypsum (1% w/w)، cement (0. 3، 0. 6 and 0. 9% w/w)، and gypsum and cement (0. 9% w/w) in 3 replicates. Amounts of soil aggregates in 53-4000 µm sizes were determined by wet sieving and MWD was calculated after one، four and seven months. After seven months، the results showed that the wheat straw، wheat straw and gypsum، and animal manure and gypsum treatments 2. 7، 3. 5 and 1. 4 times respectively increased the MWD compared to the control. Generally، based on the results of this study، application of wheat straw with gypsum، wheat straw and animal manure with gypsum for increasing the stability of similar soils is recommended.