Potassium Forms Status in Some Iraqi Sedimentary Soils and Effect of Cultivation on It

Abstract

A field experiment was carried out in Al-Hussainiya area/Al-Mussaib district within Babil Governorate to study the extraction and estimation of potassium in cultivated soil, and bush soil, and uncultivated soil, to identify the state of the soil in terms of its ability to supply potassium (poor potassium - moderate potassium - rich in potassium). Soil samples were collected from the study area in the period (1-4-2022) for each soil from the surface depth (0-30) cm and sub-surface (30-60) cm. Potassium was extracted from the study soil and the amount of potassium Soluble in water, and the exchangable, reserve-K, primary step-K and total step-K, and total K. The value of reserve-K was 0.40 and 0.46 cmol in the cultivated soil, 0.99 and 1.07 cmol in the uncultivated soil, 0.66 and 0.87 cmol in the bush soil and the surface and subsurface layers, respectively, and the initial step-K values were 0.213 and 0.487 cmol in the cultivated soil and 0.845 and 0.929 cmol in uncultivated soil and 0.48 and 0.511 bush soil, and value of total step-K was 0.982 and 0.944 cmol in the cultivated soil, 3.073 and 3.136 cmol in the uncultivated soil, 2.795 and 2.109 cmol in the bush soil and the surface and subsurface layers, respectively. Based on the results obtained and under the conditions of this study, the concentration of potassium Soluble in water and exchangable within the content of the dry and semi-arid areas, and that the exploitation of the soil by intensive cultivation constantly led to a decrease in the values of step-K and reserve-K, and that the concentration of step-K and reserve-K is lower in the subsurface layers (30-60) cm in the cultivated soil and the soil in which the bush grows. As for the uncultivated soils, the potassium values are higher and almost close in the subsurface layer compared to the surface. As a result of the conditions of use, the sequence of the step-K and reserve-K in the study soils are as follows: Cultivated soil > bush soil > uncultivated soil. In addition to the need to use potassium fertilizers under conditions of intensive cultivation.