Studies on potassium supplying power for corn of Khorat, Hin Kong, Park Chong, Takhli and Kamphaeng Saen soils [Thailand]
1988
Sakorn Soisungwan
Excess K, the amount of K that could be released for crop befor response to K-fertilizer was obtained, were 0.00,0.00,0.637,0.674 and 0.997 me K/100 gm soil for Khorat, Hin Kong, Pak Chong, Takhli and Kampaeng Saen soils respectively. It has also been predicted that response of corn to K-fertilizer was not likely to be obtained with in the next 30, 32 and 47 cropping for Pak Chong, takhli, and Kamphaeng Saen soils respectively. Depletable K, the amount of K that could be released for crop before K-deficiency symptom occurred were 0.199, 0.222, 1.071, 0.796 and 1.174 me K/100 gm. soil for Khorat, hin Kong, pak Chong, takhli and Kampheng Saen soils respectively. According, it has been predicted that visual symptom of K-deficiency was not likely to be obtained within the next croppings for Khorat soil,10 for Hin Kong soil,50 for Pak Chong soil,36 for Takhli soil and 55 for Kamphaeng Saen soil. Minimal variable ranges of the critical level of K in soils has been determined to be 0.401-0.737 me K/100 gm by NH4OAc extraction and 0.462-0.769 me K/100 gm soil by H-saturated resin extraction where as those of the threshold of deficiency level to be 0.186-0.192 me K/100 gm. Soil by NH4OAc extraction and 0.215-0.388 me K/100 gm. Soil by H-saturated resin extraction.
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