Document Type : Research Paper
Authors
1
Former M. Sc. Student Dept. of Soil Science, Urmia University
2
Prof., Dept. of Soil Science, Urmia University
3
Assist. Prof., Dept. of Soil Science, Kurdistan University
4
Assist. Prof., Dept. of Soil Science, Faculty of Agricultural Sciences, University of Guilan
Abstract
Corn (Zea mays L.) plays an important influence in human food cycle and thus assessing factors affecting its optimal yield is of great importance. Potassium status in soil is one of the most influencing inputs affecting both quantity and quality of corn yield. Potassium is not only an important nutrient for corn due to its large demand, but also plays significant roles on physiological and biochemical activities. The objective of this study was to designate an appropriate extractant for determining available K in 19 calcareous soils in Kordistan province. In order to evaluate the relationship between extractable K with different extractants and potassium uptake by corn, an experiment with corn was carried out in a completely randomized design with two levels of potassium (0 and 300 mg.kg-1 using potassium sulfate) each with three replicates. The concentrations of potassium in plants were measured and K uptake, additional uptake, plant response, relative yield and increasing concentrations were calculated. The results indicated that singnificant correlations are exist between K uptake by corn and six extractants including 1M NH4OAc (r=0.84**, P≤0.01), 0.1 M BaCl2 (r=0.74**, P≤0.01), 1 M NaOAc (r=0.69**, P≤0.01), 1 M NaCl (r=0.67**, P≤0.01), 0.1 M HNO3 (r=0.64**, P≤0.01), and 0.01 M CaCl2 (r=0.55*, P≤ 0.05). However, considering cost effectiveness, applicability aspects, extraction duration and its relationship with plant indices, the 1M NaOAc extractant can provide the most useful prediction for K uptake by corn in calcareous soils of Kurdistan.
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