In the 31st-34th years (2001-2004) of a long-term NPK fertilization experiment set up on calcareous sandy soil in the region between the Danube and the Tisza in 1970, studies were made on the effect of the treatments on the mineral composition and hay yield of alfalfa and on the AL-soluble PK content of the ploughed layer. The soil contained around 1% CaCO 3 and humus and 5-10% clay in the ploughed layer, while the subsoil was strongly calcareous. The groundwater was at a depth of 5-10 m and the area was prone to drought, with poor supplies of available nutrients (NPK). The major conclusions were as follows: - The hay yields in the experimental years (8 cuts) amounted to 5.8 t/ha on the control soil, 8.4, 9.5 and 12.5 t/ha in the N 1 P 1 , N 2 P 2 and N 2 P 2 K 4 treatment, respectively. In the NP treatments, yield surpluses were recorded in the first two years. By the 3rd and 4th year, the available K supplies of soils/subsoils given no potassium had been exhausted, thus making the soils infertile for alfalfa. - The N content of the alfalfa fluctuated greatly depending on the treatment, the year and the cut. N contents of around 2% were recorded in the first cut on N-deficient soils and around 7% in the 4th cut on NP-fertilized soils. In the NP treatment the N content was doubled compared with the control in the 1st cut. Later the hay N% increased even on unfertilized soil, so the effect of NP fertilization was less pronounced. - The hay K content ranged from 0.9 to 3.6%, with extreme K deficiencies in the control and NP treatments. In response to higher K rates, the 1.5% mean K content recorded in the control rose to 3.0% and the desirable 1.0-1.5 N/P ratio was restored in the shoot. - With improved K supplies the concentrations of Ca, Mg, P, Sr, Mn, Na and B in the hay declined compared with the control and NP treatments. By contrast, NP fertilization significantly improved the incorporation of P, S and Sr into alfalfa shoots. This could be attributed to the fact that the superphosphate applied had mean contents of 13% S, 8% P and almost 2% Sr, thus serving as a source of S, P and Sr for the plants. - The supply limits published in the literature for leaf diagnostics could be suitable for determining the nutrient status of alfalfa and, indirectly, the nutrient-supplying capacity of the soil. They could thus be used for the estimation of fertilizer requirements. In the present experiments, mean soil contents in excess of 3.5% N, 2.5% K and 0.3% P were found to be satisfactory in the green bud stage, in line with data given in the literature.
|Translated title of the contribution||Effect of mineral fertilization on the element content of alfalfa (Medicago sativa L.) on calcareous sandy soil|
|Number of pages||16|
|Journal||Agrokemia es Talajtan|
|Publication status||Published - Dec 1 2009|
ASJC Scopus subject areas
- Agronomy and Crop Science
- Soil Science