Potassium placement effect on dynamics of barley (Hordeum vulgare L.) nutrition

The effects of local placement of potassium (K) on mineral nutrition dynamics of barley (Hordeum vulgare L.) in fertile Сhernozem were studied. A pot experiment with local K-placement at 4–5 cm soil depth was carried out and the dynamics of nitrogen, phosphorus, potassium (NPK) concentrations in tillers, organs and parts of spring barley was measured. K-placement increased the productivity index from 0.49 to 0.54, despite optimal and slightly varying NPK concentrations during the second half of the vegetation period (60–100 d). This occurs due to partitioning of assimilates, N, K, and especially P in generative organs of primary and secondary tillers forming quality grains. Nutrient concentrations in certain primary tiller parts of a 60-d plant (senescing leaves and the main spike axis) proved to be more sensitive indicators of the K-placement effect than average whole-plant characteristics. While being beneficial, K-placement had little impact on the overall NPK removal in barley, which shows a significant role of factors related to K uptake kinetics. Thus, the chosen parameters in the soil–plant system (the high content of available K in Chernozem, in the second part of the vegetation period) have for the first time allowed the evaluation of the impact of local K-placement on mineral nutrition dynamics in barley.