Effect of phosphorus placement on wheat yield and quality in Southwestern Buenos Aires (Argentina) |
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| Abstract: | Abstract In the Southwest of Buenos Aires Province (Argentina), wheat yields are limited by phosphorus (P) deficiencies in at least 50% of the area. The objective of this paper was to report on the relative efficiency of two different methods of application of ? fertilizer: (i) by row placement with the seed at sowing (RP) and (ii) by broadcasting and incorporation into the surface soil (BP). The design of the experiments was of complete blocks with a strip subplot. Treatments were ? rates and method of application. Subtreatments were ? fertilization at different times and rates. ? fertilizer was triple superphosphate (TSP). One experiment included diammonium phosphate (DAP). Yield response to ? was significant in 3 of the 4 experiments. The RP produced higher yields in three experiments, but differences were significant in only one site. The RP effects on yield are shown by comparison of yields for individual treatment rates and by the calculation of fertilizer efficiency, efficiency ratio and substitution rate (S), which is defined as the ratio of RP and BP rates rendering the same yield response. Of these, the substitution rate showed the most highly significant effects. Fertilizer efficiency for TSP broadcast ranged from 8 to 44 kg wheat kg‐1 P. Efficiency ratio of RP to BP for a rate of 16 kg ? ha‐1 was between 1.27 and 1.74. The S was significant in two experiments carried out on sandy loams where values of 0.31 and 0.39 were found for soils with 6 and 10 mg ? kg‐1 (Bray I). In general, RP improved wheat quality as determined by kernel and volume weight and also the ability of the crop to compete with weeds (Avena fatua). |
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