2004 - Effects of Time and Rate of Phosphorus Application on Rice Growth and Phosphorus Uptake
2003 - Rice Response to Phosphorus Fertilizer Application Time and Rate
2002 - Effect of Phosphorus Fertilizer Rate and Application Time on Rice Growth and Yield
2001 - Time and Rate of Phosphorus Fertilizer Application on Rice Growth and Phosphorus Uptake
Time and Rate of Phosphorus Fertilizer Application on Rice Growth and Phosphorus Uptake, 2001
Phosphorus (P) fertilizer applied near the time of flooding has proved to be equal and sometimes superior to preemergence applications on soils (alkaline silt loams) that require P to produce maximum rice yields. The objectives of this research were to: 1) measure rice biomass and P uptake during the growing season and 2) measure rice grain yield response to P fertilizer application time and rate.
A single field study was established on a high pH (> 8.0) silt loam soil to evaluate P fertilizer rates at 0, 25, 50, and 100 lb P2O5/A, applied before emergence, preflood at the 5-leaf stage, at 1.25-inch internode elongation, or after the flag leaf was fully emerged. Biomass production and tissue P concentrations were monitored during the growing season, and grain yield was measured at maturity. The time of P fertilizer application was the dominant factor affecting rice biomass production, tissue P concentration, and grain yield on an alkaline silt loam soil. Phosphorus fertilizer applied before flooding at the 5-leaf stage resulted in consistently higher biomass production, tissue P concentration, and grain yield than the untreated check and numerically higher values for these growth parameters than all other times of P application.
Data from this study strongly suggest that the time of P fertilizer application has a profound influence on fertilizer use efficiency on alkaline silt loam soils. Phosphorus fertilizer applied before rice emergence is apparently fixed into forms that are not immediately available for rice uptake after flooding. AR-22F