engleski

Potassium status as a nutritional problem in hydromorphic soils of eastern Croatia

Potassium (K) nutritional problem in the field crops, especially maize (edge necrosis of leaves, small and unfinished cob, inclination to stalk lodging at maturity stage, low yields) has been found on some hydromorphic clay soils situating in the left side of Sava valley area in the eastern Croatia region. Alkaline reaction, high levels of exchangeable magnesium (Mg) and calcium (Ca), as well as strong K- fixation are mainly in coincidences with K nutrition disorders. Three rates of KCl (containing 60% K2O) were incorporated in Ivankovo soil (pH in KCl = 7.30 ; AL-soluble P and K = 6.9 mg P2O5 and 8.8 K2O/100g) before maize sowing on the ordinary fertilization (kg/ha: 170 N + 130 P2O5 + 130 K2O) as follows (basic plot of fertilization 0.86 ha): a = 0 (control), b = 470, c = 660, d = 980. As affected by additional K fertilization grain yields of maize were increased up to 60 % and they were as follows (t/ha: 2-year means): 6.10 (a), 7.68 (b), 8.92 (c) and 9.75 (d). Also, improvement of K supplies due to K fertilization resulted by considerable decreases of stalk lodging at maturity: 48 % (a), 16 % (b), 12 % (c) and 10 % (d).

Potassium ; fertilization ; maize yield ; K-fixing soil

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