In the 20th year of a long-term fertilisation experiment set up on loamy chernozem soil with lime deposits, tests were made on the effects of various N, P and K supply levels and their combinations on weed infestation, and on the development, yield components and mineral composition of silage maize. The soil of the experimental location contained 3% humus, 5% CaCO3 and 20% clay in the ploughed layer, and was supplied moderately well with N and K and poorly with P and Zn. The experiment consisted of 4N×4P×4K = 64 treatments in two replications, giving a total of 128 plots. The fertilisers were applied in the form of calcium ammonium nitrate, superphosphate and potassium chloride. The groundwater was at a depth of 15 m and the area had a tendency to drought. The spring and the first half of the summer were dry in the experimental year. The main results can be summarised as follows: 1. Weed infestation data recorded prior to sowing indicated that the average 2.5% weed cover on the control soil rose nearly 4 times as the result of P fertilisation. The species Amaranthus blitoides made up 85% of the weed cover. 2. The highest yields (6.7 t grain + 7.5 t stalks + 1.1 t cobs = 15.3 t/ha air-dry aboveground yield) were achieved in treatments provided with 100 kg/ha/year N rates, but given no P fertiliser for 20 years. In this treatment the ploughed layer contained AL-P2O5 supplies of 78 mg/kg, classified as poor" by the Hungarian fertiliser recommendation service. The yield was not influenced by K fertilisation. 3. On soil containing 263 mg/kg AL-P 2O5, classified as "well-supplied", the mean plant density at harvest dropped from 65,000 to 26,000 per hectare, the 1000-gram mass from 309 to 292 g and the aboveground air-dry matter to a third, 5 t/ha. In agreement with the results of previous analyses, this yield loss could be attributed to Zn deficiency induced by the excessive P. The P/Zn ratio increased from an optimum value of around 100 on the control soil to around 300, both in 4-6-leaf shoots and in the grain yield. Under such conditions, Zn fertilisation is definitely justified. 4. The nutrient quantities incorporated in the maximum yield of 6.4 t/ha grain + 6.4 t/ha stalks amounted to 144 kg N, 85 kg K, 30 kg Ca, 25 kg Mg, 19 kg P and 14 kg S. Under the given conditions, the P requirements of maize may be over-estimated by some 50% by the Hungarian fertiliser recommendations. The microelement uptake was found to be 554 g Mn, 237 g Na, 240 g Zn, 86 g Sr, 59 g Cu, 38 g Ba, 36 g B and 5 g Ni per hectare. The uptake of As, Sc, Co, Cr, Hg and Cd was below the g/ha detection limit.
|Number of pages||13|
|Publication status||Published - Jun 1 2004|
ASJC Scopus subject areas
- Agronomy and Crop Science