The effect of NPK supply levels and their combinations on the nutrient content, nutrient uptake and optimum diagnostic values of hemp (variety Kompolti) was examined in the 16th year of a long-term mineral fertilisation experiment. The ploughed layer of the calcareous chernozem loam soil contained around 3% humus, 5% CaCO3 and 20% clay, and was poorly supplied with P and Zn and moderately well with N and K. The experiment involved 4N×4K×4P=64 treatments in two replications, giving a total of 128 plots. The fertilisers were applied in the form of calcium ammonium nitrate with a 25% N content, 18% superphosphate and 50% potassium chloride. The groundwater was at a depth of 13-15 m and the area was prone to drought. The main results were as follows: 1. With improving N supplies there was an increase in the N concentration of the plant organs, and to some extent in that of K, Ca and Cu. Rising P supplies caused an increase in the P, Ca and Mn reserves, while the Zn content declined due to the pronounced P-Zn antagonism. Excessive K supplies led to a 2-3 times increase in the K %, with a consequent reduction in the incorporation of Ca, Mg and Na cations. 2. There was a decrease of approximately one order of magnitude in the N, Ca, P, Fe and Mn contents of the young shoots and leaves compared with that in the stems at harvest. The fibres and tow lost even more nutrients, especially K, during retting. 3. Optimum nutrient supplies to fibre hemp arc represented by values of 4-5% N, 0.4-0.5% P and 4-5% K in the 20-40 cm shoots on May 30th, or by ratios of 0.8-1.2 N/K, 8-12 N/P and 8-12 K/P. The analysis of fully developed young leaves from the 2nd or 3rd leaf zone (100-150 cm stand) on June 26th revealed that the optimum range was 4-5% N, 0.3-0.4% P and 2-3% K, or ratios of 1.5-2.5 N/K, 5-10 K/P and 10-15 N/P. 4. A total of 146 kg N, 310 kg K2O, 221 kg CaO, 35 kg MgO, 46 kg P 2O5, 2.7 kg Na, 1.4 kg Fe, 580 g Mn, 244 g Zn and 50 g Cu were incorporated into the 13.2 t/ha air-dry yield of leafy stems at harvest. If the leaves are ploughed back into the soil, 61% of the Ca, 56% of the Mg, 53% of the N and 43% of the P can be recycled. Among the micronutrients, Fe was mainly accumulated in the leaves, and Na, Mn, Zn and Cu in the stems. 5. The specific clement contents in 10 t stems + the associated leaves at harvest ranged from 83-152 kg N, 27-48 kg P2O5, 142-323 kg K 2O, 180-220 kg CaO, 37-68 kg MgO, 1.8-2.9 kg Na, 1.0-1.4 kg Fe, 310-604 g Mn, 254-306 g Zn and 48-52 g Cu, as a function of NPK supplies. 6. On the basis of data in the literature and the present analyses, the following mean specific parameters are recommended for extension services in Hungary (for the estimation of the nutrient requirements of the planned yield): 100 kg N, 40 kg P2O5, 200 kg K2O, 140 kg CaO and 40 kg MgO. Naturally, Ca and Mg fertilisers will not be required at calcareous locations.
|Translated title of the contribution||Mineral fertilisation of fibre hemp (Cannabis sativa L.) on calcareous chernozem loam soil. II|
|Number of pages||14|
|Publication status||Published - Dec 1 2004|
ASJC Scopus subject areas
- Agronomy and Crop Science