تأثير النظام الزراعي في بعض صفات التربة الفيزيائية ضمن اقليم الرز في العراق

Abstract

This study was carried out to investigate the effect of long-term agriculture on the monoculture system of rice crop and the crop rotation system of rice-wheat crops compared to not cultivated soil in some soil physical properties within the rice region southern Iraq. A representative pedon was diagnosed at each of the above agricultural systems in three locations, namely the Abbasiyah, Shami and Mashkhab districts within the provinces of Najaf and Qadisiyah, so that the land use period is not less than 50 years. Disturbed soil samples were collected from each diagnosed horizon at each site, and some physical characteristics were estimated. The results showed the values of the clay separate was ranged from 101-395 g.Kg-1 , sand 56-512 g.Kg-1 and silt 325-837 g.Kg-1 . The soil texture in the three study area was within the medium to fine classes, the results also showed that there was a difference in the bulk density values of the studied soils, it was ranging from 1.31 - 1.78 Mg.m-3 , the highest values for this parameter were recorded in the pedons which used in the crop rotation system compared to the monoculture system, with a significant increase in soil resistance for penetration values, reached 18.3% compared to non-cultivated lands soil. There was also a significant increase in the weighted diameters rate when the land cultivated, it was increased from 0.08 mm in the not cultivated soils to 2.01 mm and 2.15 mm in the monoculture and crop rotation farming systems.