The aim of this work was to analyse the effect of K, P and N supplies on the yield of winter barley in a long-term mineral fertilisation experiment with clearly distinct soil nutrient supply levels in order to develop fertilisation guidelines for winter barley growers. The experiment was set up in 1989 on a chernozem meadow soil calcareous in the ...deeper layers, applying all possible combinations of 4 levels each of N, P and K fertiliser, giving a total of 64 treatments.
The results of analyses performed in 2011 and 2012 can be summarised as follows:
In 2011, when rainfall supplies were deficient in the shooting phase, improved K supplies (324 mg kg-1 AL-K2O) increased the grain yield, but in 2012, when rainfall supplies were more evenly distributed, K supply levels in the range 210–335 mg kg-1 AL-K2O had no significant influence on the yield of winter barley.
An analysis of the P treatments revealed that, compared to the 119–133 mg kg-1 AL-P2O5 level (P0), better P supplies (186–251 mg kg-1) led to a significant increase in the grain yield.
In both years rising N rates significantly increased the yield up to an annual N rate of 160 kg ha-1.
4. A K×N interaction could only be detected in the nutrient supplies of winter barley in 2011. The yield-increasing effect of N fertiliser was more pronounced at better K supply levels, while K fertiliser led to higher yields in the case of better N supplies.
The effect of the N, P and K supplies of soil on the grain yield and N, P and K status of maize was studied in a long-term mineral fertilisation experiment between 2001 and 2008 and nutrient supply limit values were determined to plant analysis. Based on the interaction between the N concentrtion of maize leaves measured at the beginnig of tasseli...ng and grain yield, the satisfactory limit value of N supply to reach 10–14 t ha-1 yield was between 2.0–4.0%. Leaf analysis at the beginning of tasselling indicated that better P and K supplies were associated with a higher P and K concentration in the maize leaves. Correlation analysis on the P concentration of the maize leaves and the grain yield showed that at a grain yield level of 10–14 t ha-1 a P concentration of 0.20–0.37% represented a satisfactory P supply level. The satisfactory K supply limit value to reach 10–14t ha-1 grain yield was 1.5–2.6%.