Grains and field crops
The excessive amounts of nutrients entering the Peel-Harvey Estuarine system have resulted in a marked increase in the abundance of algal species .within the estuary and reduced production on the sandy coastal soils of the catchment from which the nutrients are being leached. Recent stream samplings by D.C.E have shown that the deep grey Bassendean sands may be contributing up to 40 per cent of the total P loading in the Harvey River. Agriculture Department trials around Albany on similar sands have shown that up to 80 per cent of the bicarb extractable P may be lost after only 150 mm of rain. Phosphorus rundown trials. 82HA14, 82HA15, 82HA16, 82HA17, 82HA18. Soil test calibration curve trials. 82HA20, 82HA21, 82HA22, 82HA23, 82HA24, 82HA25, 82HA26, 82HA27, 82HA28, 82HA29, 82HA30. P sources x rates x times of application trials. 82HA31, 82HA32. P sources leaching trials. 82HA33, same site as 82HA31, 82HA34, same site as 82HA32. Lime rates with + P. 82HA36, 82HA37, 82HA38, Old land same site as 82HA28. Overall summary. The reverted superphosphates are at least as good as normal superphosphate as far as pasture yield and P uptake are concerned, however bicarb P results indicate considerably less leaching. The very insoluble phosphate areas do not leach to any degree but are less efficient than superphosphate in pasture nutrition. The performance of these less leachable sources is expected to improve relative to superphosphate in subsequent years. The two leaching trials show that there is little difference in P leaching on new and old land sites, however the build-up of organic material on old land appears to have a marked effect on Potassium retention. In 1983 all treatments in the soil test calibration curve trials should have different residual values of P and splitting each plot into untreated and adequately supplied halves should give many points for the soil test calibration curves. From the three trials reported here it would appear that there is no interaction between P nutrition and added lime, however improved pasture management on these trials in 1983 should give more data.
Number of Pages
Deeley, D M, Mason, S M, and Barker, B G. (1982), Phosphorus Nutrition on Leaching Sands.. Department of Agriculture and Food, Western Australia, Perth. Report.