Determination of Potassium Adsorption Isotherm and Its Exter | 104330
International Research Journals

Determination of Potassium Adsorption Isotherm and Its External and Internal Requirements for Optimum Yield of Wheat (Triticum aestivum L.) on Soils of Central Highlands, Ethiopia


Getahun Alemayehu*, Asmare Melese and Wondwosen Tena

Low soil fertility is a major constraint that limits wheat production in Ethiopia. Application of Potassium (K)fertilizer in the area is limited. This study aimed to assess K status, adsorption capacity of soils andto determine K requirements for wheat. Eight Kebeles from the district were selected. Soil analysisshowed that pH of soils were ranged from neutral to strongly acidic; clayey in texture; low to moderate% OM and total N; moderate to high CEC; medium to very high Ca and Mg and medium to high contentsof K were recorded. The pot experiment laid out was in Complete Randomized Design (CRD) with threereplications using Danda’a wheat variety as a test crop. K was determined from filtrate of 2.5 g of soil in25 mL solutions of 0, 25, 50, 75, 100, 125, 150, 175, 200, 225 and 250 mg/L K. Soils of the experimentalsites showed different K adsorption characteristics and their adsorption rates ranged from 51.82 to70.08%. The highest adsorption rate recorded on vertisols. The adsorption data fitted better toFreundlich model, and used to compute K doses for pot application. The study found that wheat growthand yield parameters were increased as K increased and reached their optimum levels of 148 kg/haand 145 kg/ha of K that produced 3,556 kg/ha and 4,826 kg/ha of wheat at each sites. Internal Krequirements were 0.77% and 0.78% for Godnamamas and Cheki, respectively. Generally, wheat yieldshowed a significant response to K fertilizer.

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