Influence of phosphorus supply pattern in soil on yield of spring wheat

The purpose of this research was 1) testing the influence of various patterns of supplying phosphorus (P) on dry matter production and biomass allocation in various organs of spring wheat and 2) exploring the optimal P application pattern for high grain yields of spring wheat. Plants were grown in pots constructed with PVC tube, 130 cm long and 10 cm in diameter. Each tube consisted of two segments of 0–43 cm and 43–130 cm. Two soil water regimes were imposed: i) D, water content in the upper soil layer was kept at 50% of field capacity (FC), lower layer (43–130 cm) was at 75–80% of FC and ii) W, a well‐watered control with the entire soil profile being maintained at 75–80 FC. Three P applications were made: i) Pu, P was supplied in the upper 0–43 cm soil layer, ii) Pl, P was supplied in the 43–130 cm layer, and iii) Pe, P was supplied to the entire soil profile. Total photosynthates of plants in WPe and WPu in a whole day were higher than that in DPe and DPu. The photosynthetic rates were similar between WP1 and DPl. The highest P/T (Photosynthesis/ Transpiration) in topsoil drying treatments occurred in DPu, but in wet treatments it was Wpe. The DPu and WPu had similar leaf area, which were significantly higher than other treatments. In the period from the beginning of water treatments to harvest, water consumption in DPe, DPu, DPl, WPe, WPu, and WP1 was 419, 354, 476, 763, 565, 806 mL, respectively. At harvest time, supplied water use efficiencies of DPu and WPu were similar, and reached a peak in both drying and wet treatments. Grain weights per shoot in DPu and WPu were significantly higher than those of other treatments. This implies that phosphorus supplied to the upper soil is beneficial to yield maximum.