Effect of the long-term NP fertilizer application on the available potassium content of some soils in north Bulgaria
1997
Stoichev, D. | Donov, D. | Stoicheva, Dimitranka (N. Poushkarov Research Institute of Soil Science and Agroecology, Sofia (Bulgaria))
Data about the influence of a long-term mineral fertilisation on the potassium uptake and its available content in the arable layer of main soils in North Bulgaria (Chernozem and Grey Forest) are presented. The study has been conducted on the base of the field experiment with maize grown as monocropping under irrigation. Four treatments with different NP rates without potassium application are compared with non-treated variant. Results from the investigation show that total potassium uptake varies from 1182 to 2949 kg ha-1 and depends closely of NPK rate of application. Some decreasing of the available potassium is pointed out at the end of the 15 year in the arable layer only of the Grey Forest Soil in the treatment where maximum N-uptake is realised. At all other cases changes of available potassium content are statistically not significant
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