| Autor: |
COOKE, G. W., MATTINGLY, G. E. G., WILLIAMS, R. J. B. |
| Zdroj: |
Journal of Soil Science; 1958, Vol. 9 Issue 2, p298-305, 8p |
| Abstrakt: |
A four-course rotation experiment was carried out on wheat, mangolds, barley, and legumes. Yields of all crops were much increased by phosphate fertilizers, nitrogen fertilizers increased yields of non-legumes, extra yields from potash fertilizers were smaller. Fifty-six years of continuous manuring caused the following changes in the calcareous boulder clay soil: Plots receiving farmyard manure contained half as much again organic carbon as plots receiving fertilizers, plots receiving N and P fertilizers contained slightly more organic matter than plots without these fertilizers. Total soil nitrogen was considerably increased by farmyard manure and was slightly higher on plots receiving sodium nitrate than on plots without nitrogen fertilizer. Total soil phosphorus was built up by farmyard manure and by bone meal, and to a smaller extent by light annual dressings of superphosphate. 'Soluble phosphorus' determined by three methods differentiated clearly between plots which had received phosphate fertilirs and those which had received none. An accumulation of bone meal residues was demonstrated by dilute hydrochloric-acid extraction, but not by methods involving extraction with 0.5 M sodium bicarbonate or equilibrium with 0.01 M calcium chloride. Soluble-phosphorus values by all three methods indicated the presence of fertilizer residues more clearly than did values for total soil phosphorus. The soil contained a large quantity of total potassium and the values were not materially affected by manuring. Dilute-HCl-soluble-K and exchangeable-K values differentiated between plots which had received potash fertilizers and those which had received none. They also reflected changes in soluble potassium caused by the different amounts of potassium removed in the crops grown. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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