FORMS AND DISTRIBUTION PATTERN OF SOME GYPSIFEROUS SOIL HORIZON COMPONENTS IN SALAH- AL DIN GOVERNORATE

Abstract

Three pedons representing arid gypsiferous soils in Sallah-Al-Din governorate of Tikrit have been selected for studying the vertical distribution of some soil components and its relation with irrigation methods ( without irrigation ,sprinkler irrigation ,surface irrigation ) .The soils were classified as Aridisols and subgreat group Calcigypsids. The results showed a significant effects to the land use, especially center piovot irrigation and plowing on the distribution of soil components , horizons thickness and development .Most of the studied soil pedons were silty loam, non-saline with a slightly alkalinity. Moreover, the predominant types of soil structure were complex, spongy, massive and subangular blocky . Cultivated Ahorizon was thicker ( 25 – 26cm) than uncultivated A horizon( 13) cm. Morphological description ,physical , chemical analysis, and thin section technique showed that there is a significant difference in vertical distribution of soil separates. The occurance of desected clay-ferran skin(ferriargillans ) were found either around soil particles or in the internal pores surface as well as calcitans and gypsans which indicates down word movement of some soil component due to pedogenic processes .Soil development indices ( C.I) reflected the development of cultivated soil pedons (3.75,38.2 ), while these indices (1.12,1.67 ), indicates that the non-cultivated soil pedons were not developed. Dominant pores were ,chamber, channel, complex and vughs. Gypsum crystals shape were mainly spindle and lenticular. Thus, it is important to take into account the soil management and irrigation method for the future land use.

Keywords

Soil, Gypsiferous