Effect of the application of low grade rock phosphate to subsoil on the growth and phosphorus uptake of pasture plants
1997
Kondoh, H. (National Grassland Research Inst., Nishinasuno, Tochigi (Japan)) | Shibuya, T. | Kimura, T. | Kojima, M. | Yamamoto, K.
Two different grade rock phosphate or phosphorus fertilizer was applied to subsoil (20cm depth) or surface soil before the establishment of mixed sowing grassland. Effect of these different application method of the phosphorus materialize on the growth of pasture plants (white clover and orchard grass) was examined for 3 years. The growth and phosphorus uptake of the pasture plants in the plot of the subsoil application of low grade rock phosphate was comparable with those in the plot of the surface application of phosphorus fertilizer at a standard rate. In the former plot, much amount of available phosphate was found in the subsoil. This suggested that the phosphate dissolved from the rock phosphate was not readily absorbed with soil particles because of large size clods of the rock phosphate. The phosphorus uptake by pasture plants in this plot may depend upon thy phosphorus supply from the subsoil. The distribution of root system in the subsoil did not differ irrespective of the application method. The spore numbers of VA mycorrhizal fungi and the infection intensity in roots was higher in the subsoil application plot than in the surface application plot. These suggested that the phosphate dissolved from the rock phosphate in the subsoil was absorbed through the hyphae of VA mycorrhizal fungi
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