Effect of lime on EUF extractable phosphorus and potassium in the soil and nutrient uptake, yield and quality of sugar beet with varying potassium fertilization

Liming soils is of common agricultural practice. Increasing soil pH and adding calcium (Ca) may influence extractability and availability of phosphorus (P) and potassium (K) and has to be considered for the calculation of fertilizer recommendations for sugar beets using results from electro-ultrafiltration (EUF). The aim of the present study was to quantify the effects of a lime application on weakly acid to neutral soils with low EUF-Ca-contents in fraction two on (i) EUF extractable P and K in the soil, (ii) P- and K-offtake as well as yield and quality of sugar beets, in particular at different K-fertilization levels. In late summer burnt lime was applied in amounts of 0, 3 and 12 t CaO ha–1. 24 weeks after application soil samples were analyzed using EUF. Subsequently, sugar beets were grown with different fertilization regimes (N, K, Mg) on the plots with 0 and 3 t CaO ha–1. Liming did not change EUF extractable nutrients in the soil in plots fertilized with 3 t CaO ha–1. After application of 3tCaO ha–1 the P- and K-contents of beets were slightly lower than those from plots without lime; fresh matter yield rose by 1,4 t ha–1 and white sugar yield (WSY) by 0,3 t ha–1. As expected the K-fertilization resulted in a higher sugar content. Furthermore, the K-fertilization within the limed plots achieved a higher WSY than the plot without K-fertilization, though WSY did not exceed the level of the plots without lime. Conclusively, results show that an adaptation of the fertilizer recommendation for P and K is not required after lime application in common amounts.