Comparison between organic and mineral sources of potassium and their effects on potassium fractions in clay soil and productivity of potato plants under water stress conditions

Noura M. Taha ; Shaimaa H. Abd-Elrahman 


Potassium (K) is an essential element for plant growth that maintains water balance within its cells. Different forms of K were investigated for their effects on potato (Solanum tuberosum, cv. Spunta) plants grown under water stress conditions as a kind of adaptation to the climatic changes and water shortage under Egyptian soil conditions. Also, knowledge of different K fractions in the studied clay soil is important to achieve the sustainability in agriculture. Therefore, a field experiment was conducted during the two tested seasons of years 2014 and 2015 at the Faculty of Agriculture, Ain Shams University, Qalubia governorate, Egypt. Two sources of K were tested under three levels of irrigation water in a split-plot design. Results indicated that K fractions in soil were in order of total K > non-exchangeable/ fixed > exchangeable > water soluble. The 50% irrigation level of irrigation requirements (IR) combined with K-humate as ground application increased water soluble and exchangeable K in the studied soil. While there was hardly no changes observed due to the applied treatments on fixed and total amounts of K in the soil. Regarding the studied vegetative growth and yield parameters of the growing potato plants, the treatment 100% of IR combined with K-humate as soil application caused significant increases. The specific gravity of tuber, as an important indicator of potato tuber quality, recorded the highest value by applying 50% of IR combined with K-humate as ground addition, compared to mineral addition which came in the second order. Regarding the nutrient concentrations in potato haulm, results revealed that the 50% of IR combined with K-humate gave the highest content of N, while the same irrigation level with K-humate plus foliar spray gave the highest content of P and K, during the two tested seasons. In tubers, 50% of IR combined with K-humate as soil application gave the highest concentration of N and P during the two tested seasons, while 75% of IR in the first season and 50% of IR in the second season combined with K-humate plus foliar spray gave the highest values of K content. The calculated water use efficiency (WUE) showed that the highest value was obtained by 50% irrigation level of IR combined with soil application of K-humate.

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Issue Date 2018
Journal Egyptian Journal of Soil Science 
DOI 10.21608/ejss.2018.2752.1153

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