Pot test on the utilization of water soluble phosphorus 32 phosphorus 33 fertilizer phosphate on spring barley as a function of the phosphorus placement and phosphorus supply in the soil
Von Wieneke, J.; Isermann, K.; Schimansky, C.; Fuerh, F.
Landwirtschaftliche Forschung 36(3-4): 327-347
1983
Accession: 006155829
The economic application of P-fertilizer to soils with a high yield level by means of different techniques of placement (P-basal dressing mixed in in the autumn as opposed to compound fertilizer pn top in spring), is being actively discussed in agricultural practice especially because of the rise in fertilizer phosphate prices. As a contribution to this problem area, 2 pot tests with spring barley were carried out dealing with the question of yield effectiveness and utilization of fertilizer-P on soils with graduated P-content classes. Fertilizer-P in a mixed-in placement-irrespective of the volume of fertilizer and the P supply level was applied at an average of 24.7 .+-. 3.4%. It varied considerably as a top-dressing (4.5-45%). With top-dressing water supply plays a decisive role. More fertilizer-P remained available for the subsequent crop after this type of placement. In spite of the large volumes of water which have to be added in pot tests, leaching of fertilizer-P at soil depths below 5 cm only amounted to .apprx. 5%. The grain yields were not adversely affected or were even increased by top-dressing on soils with average to high P supply, but yields were significantly reduced on soils of P content class A. The highest yields were obtained in an optimum P supply class of the soil and only half extraction fertilization-irrespective of the type of placement. The extraction of total P rose considerably, comparable to a luxury consumption.