Potassium release as affected by soil indigenous properties in some soils of Upper Egypt. تأثير بعض خواص التربة علي انطلاق عنصر البوتاسيوم في بعض أراضي مصر العليا

Abstract

Recently, K has become a critical nutrient for plant growth, especially in soils of coarse textures. Moreover, K is readily leached out from soils when irrigation waters or soil solutions contain high concentrations of calcium and other cations and affected by soil clay type. Thus, a multicorrelation study was conducted to find the relations between clay contents in the investigated soils and the available forms of K in soil and investigating the reaction pathways of Kfertilizer applied at different rates to soils with different textures. Soil samples collected from 4 different sites i.e., Wadi El-Nokra, Garf Hussein, El-Gaafrah, and Adndan. A sorption experiment was conducted using a series of K concentrations (20-180 mg L -1 ) on the investigated soils. The obtained relations were fitted to three adsorption isotherms, i.e., Langmuir, Bemmelen-Freundlich, and Temkin. Results show that both water soluble-K and the NH 4 OAC-K significantly correlated with the clay contents in the study soils (P=0.020 and 0.034, respectively). Results revealed that Van Bemmelen-Freundlich isotherm model seemed to be the best model fitting K sorption data in all the investigated soils. concentrations of water-soluble K increased significantly, with increasing the rate of applied K (mg kg 1 ). It seems that soil type played an essential role in increasing the retention of K in soil, i.e., the lowest increases in the water-soluble K occurred in soils with the highest clay contents in El-Gaafrah soil (Clay, 77.45% clay), whereas the highest increases occurred in Garf Hussein (Sandy Loam, 17.91% clay) and Wadi El-Nokra (Sandy Clay Loam, 35.69% clay). water-‫مجلة‬ ‫النوعية‬ ‫للدراسات‬ ‫العالي‬ ‫المعهد‬ ‫مجلد‬ 3 ‫ع‬ ‫دد‬ 1 ‫يناير‬ ( 2023 ) ( ‫ت‬ ‫أ‬ ‫ثير‬ ‫بعض‬ ‫خواص‬ ‫التربه‬ ‫علي‬ ‫انطالق‬ ‫عنصر‬ ‫البوتاسيوم‬ …….. ) ‫ربيع‬ ‫الرحمن‬ ‫عبد‬ 918soluble K decreased significantly with increasing contact time. NH 4 OAc-K increased in soil with increasing the rate of applied K. On contrary, these concentrations increased with increasing the contact time with soil.