A glasshouse evaluation of sulfur fertilizer sources for crops and pastures, 3. Soluble and non-soluble sulfur and phosphorus sources for pastures
1994
Lefroy, R.D. | Dana, M. | Blair, G.J. (New England Univ., Armidale (Australia). Dept. of Agronomy and Soil Science)
A randomized block experiment was conducted under glasshouse conditions. Undisturbed soil cores of an Aquic Haplustalf soil were oversown with perennial ryegrass and white clover, and a factorial combination of two S sources (elemental S and gypsum), two P sources (triple superphosphate, (TSP), or North Carolina reactive phosphate rock (RPR), two methods of S and P application (S mixed with granulated TSP or RPR and S coated onto TSP or granulated RPR). Pots were either watered to field capacity (NL) or watered to 25 percent excess to promote leaching (L). Harvests of tops were made at 4 or 8 weekly intervals up to 96 weeks after application when the pots were destructively harvested. Yields were lower in the leached than the unleached pots between weeks 8 and 44 where TSP or G was applied. Clover yields were initially highest with G, but elemental S gave more sustained production. Yields and P content of tops were lower with RPR than TSP up to week 36. Recovery of fertilizer S was higher in the TSP than RPR treatments up to week 24. Leaching losses of S were higher from G than elemental S sources up to week 17 and were higher where TSP was the P source. Manipulation of P and S source has been shown to improve the efficiency of utilization of the applied fertilizers.
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