The effect of potassium and phosphorus fertilizers on the potato yield depending on pedoclimatic conditions
2003
Astover, A. | Roostalu, H. (Estonian Agricultural Univ., Tartu (Estonia). Institute of Soil Science and Agrochemistry)
On potassium poor soils, the average effectiveness of K60 fertilizer norm is 60-80 kg of tubers per kg of K2O, while in favourable years it can be as high as 120-140 kg. On soils with lactate soluble potassium below 130 mg K2O kg*[-1), moderate amounts of potassium fertilizers provide a yield increase of potato almost every year. On soils with very high potassium content, potassium fertilizers ensure yield increase only in one to three years out of ten. An increase in soil potassium content by 10 mg K2O kg*[-1) decreased the average effectiveness of the K60 rate by 5.5 kg of tubers per 1 kg of K2O applied. Phosphorus fertilizers produce a positive effect every other year on soils with the lactate soluble P2O5 content below 200 mg kg*[-1). On phosphorus poor soils (below 70 mg kg*[-1)), the effect of phosphorus fertilizers is evident almost every year, and the effectiveness of the use of low phosphorus amounts (P60) is on average higher than 50 kg of tubers per kg P2O5. The increase of plant available phosphorus in soil by 10 mg kg*[-1) results in reduction of P60 use by 3.2 kg of tubers on average per 1 kg of P2O5 applied.
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