Mineral fertilisation of winter barley (Hordeum vulgare L.) on calcareous loamy chernozem soil

The effects of different levels of N, P and K supplies and their combinations on the aboveground yield (tillering, heading, flowering, grain, straw, husks), mineral composition and element ratios of winter barley were studied in 1979 in the 6(th) year of a mineral fertilisation experiment set up in autumn 1973. The agro-chemical properties of the soil in the ploughed layer were as follows: CaCO3 5%, humus 3%. clay content 20-25%, pH((KCl)), 7.3. The growing site had good supplies of Mn, satisfactory supplies of Mg and Cu, moderate supplies of N and K and poor supplies of P and Zn. The experiment was carried out with 4N x 4P x 4K= 64 treatments in two replications on a total of 128 plots. The plant samples consisted of the aboveground parts of 4 running metres per plot (0.5 m(2)). The second half of the vegetation period was very dry. The main results were as follows: 1. No K effects were observed. The original 120-140 mg/kg AL-K2O content of the soil was sufficient to satisfy the K requirements of winter barley. Satisfactory P supplies were provided by 150-200 mg/kg AL-P2O5, and satisfactory N supplies by 100 kg/ha/year. 2. N fertiliser applied alone did not increase the yield, while the shoots showed an increase of 10 times at tillering, 6-8 times at heading and 3-4 times at flowering after NxP fertilisation compared to the unfertilised control. The grain yield at harvest rose from 2.5 to 4.1 t/ha. Due to the summer drought excessive N fertilisation led to a 0.7 t/ha reduction in yield. The 1000-grain mass dropped from 26 to 2 1 g as the result of excessive NxP fertilisation. 3. On P-deficient soil the plants had poor tillering and the stand was short and chlorotic, exhibiting an approx. 2-week retardation in development. During the ripening stage these differences gradually disappeared. Between flowering and harvesting the aboveground air-dry matter yield rose by 1.7 t/ha on the P control soil, while it decreased by 1.9 t/ha on the N3P3K3 plots. 4. Satisfactory NPK supplies to winter barley were characterised by shoot nutrient contents of 4-5 % N, 3-4% K and 0.4-0.5 % P at the end of tillering. The limit concentration ranges published in the literature for diagnostic purposes can be used as guidelines in the extension service. 5. Balanced NPK supplies to winter barley were indicated by ratios of 10-15 N/P, 8-12 WP and 1.0-1.5 N/K in the shoots at tillering. The literature optima contain diagnostic information and can be used in the extension service.