STATUS AND DISTRIBUTION OF DIFFERENT POTASSIUM FORMS IN CALCAREOUS SOILS IN NORTHERN IRAQ

Abstract

1n the last few years, the demand increased especially in the developing countries for food production. One of the parameters to increase the production quantitatively and qualitatively is the use of fertilizers by following the modern techniques in fertilization which needs a detail soil studies. This study highlighted on behavior of different forms of potassium, their distributions through soil profile, and the relationships between them and with soil other properties.To represent a detailed study of the potassium behavior, twenty two surface (0-15cm) and subsurface (15-30cm) soil samples were selected from Nineveh province. The soil chemical and physical properties of each location are different.Distribution of different forms of K in these soils, i.e., available, water soluble (H2O-K), exchangeable (NH4OAc-K), non-exchangeable (HNO3-K), mineral and Total forms were ranged from (0.708 to 1.167),( 0.006 to 0.146), (0.691 to 1.124), (1.150 to 3.261), (35.48 to 52.81) and (38.78 to 58.65) respectively, for surface soil and (0.559 –0.997),( 0.003-0.105), (0.554 to 0.914), (0.997 to 2.801), (30.04 to 56.77) and (32.55 to 60.88) respectively, for sub-surface soil. Correlation study showed that the various forms of K were positively and significantly correlated amongst themselves and with CaCO3 content of the soils negatively. The water soluble, exchangeable; available; nonexchangeable and mineral potassium constituted only 0.075; 1.65 ;.1.73; 3.95 and 92.03 percent of the total-K respectively.