Prediction of soil structure parameters dependent of physical properties at different soil management and texture

This study was an attempt to predict the value of some soil structure parameters of MWD and WSA% as a function of soil content ( organic matter , total porosity, sand silt, clay) at different of soil management and soil texture. Six  soil samples of the depth 0-30 cm were selected from three sites that different in texture of Clay, loam and Sandy loam  in Basra Governorate (Abi Al-Khasib, Madinah and Zubair). Three samples represented the treatment of soil management (soil cultivated with alfalfa crop for 7 years respectively), and the other three samples from the same sites for uncultivated soil (bare soil) with three replicates for each sample. Soil organic matter content, total porosity , mean weight diameter,  water aggregate stability percentage and particle size distribution were  measured. The results showed that the MWD and WSA% as a function of some soil constituents( organic matter, total porosity, clay, silt and sand )  was represented by a highly  significant linear equations. The correlation coefficients were highly significant  and positive for all the studied constituent except for the sand, which it was negative.The results also showed that the change in the WSA% was greater compared   with  the MWD  value depending at the changing of soil constituents. This is reflected in the increasing ​​of the regression constants of the linear equations.The results show that the highest values ​​of soil structural parameters were in the soil management treatment (cultivated soil) and increasing of clay and silt. The variation of the effect of soil constituent on both MWD and WSA% by using the linear correlation equation, The constituent were entered as independent variables to predict these two parameters in multiple linear correlation equations for soil constituents at a probability level of 1%.As this led to a very large increase in the values ​​of the correlation coefficient, which indicates the possibility of using multiple correlation equations for the constituents of the study soil to predict the values ​​of structural parameters. ____________________________________________________________ Keywords: soil management, mean weight diameter, water stability aggregate.