Relationship of phosphorus application rate, winter wheat yield and soil available phosphorus content

Objectives We studied the influence of phosphorus (P) application level on tiller-earing, yield, and the absorption and utilization of P in winter wheat.

Methods From 2018 to 2021, a field experiment was conducted in Luoyang, Henan Province. Four P₂O₅ levels (0, 90, 180 and 270 kg/hm²) were setup, recorded as P₀, P₉₀, P₁₈₀ and P₂₇₀ treatments, respectively. The dry matter accumulation, P content in different organs at the main growing stages of wheat, the yield and yield components were recorded. After harvest, 0–20 cm soil samples were collected for the determination of available P.

Results Among the P treatments, the maximum and effective tiller number, and the dry matter accumulation of winter wheat were in order of P₂₇₀>P₁₈₀>P₉₀>P₀, while the grain number per spike, the dry matter allocation rate in grains and yield increased first and then decreased. P₁₈₀ recorded the highest yield (9.8‒10.2 t/hm²), which was 17.3%‒18.2% higher (P<0.05) than P₉₀, but similar with P₂₇₀. The P concentration of stems, leaves, glume shells, spike shafts and grains of winter wheat were in order of P₂₇₀>P₁₈₀>P₉₀>P₀, while the grain P accumulation reached pick under P₁₈₀ (57.0‒61.1 g/m²). Compared with P₉₀, P₁₈₀ significantly (P<0.05) increased grain P accumulation by 27.7%‒39.0%. The partial productivity of P and the agronomic utilization efficiency of P in winter wheat showed a decrease trend with the increase of P application levels. Compared with P₉₀, the P partial productivity and P agronomic utilization efficiency of winter wheat at the P₁₈₀ and P₂₇₀ levels decreased by 40.0% to 41.1%, 35.3% to 36.1% and 62.1% to 64.7%, 58.6% to 62.8%, respectively. P application levels had linear relationship with soil available P content, but the relationship of wheat yield with P application levels and soil available P content could be fitted with quadratic equations.

Conclusions Suitable application rate of phosphorus can significantly increase the number of effective tillers and panicles of winter wheat, increase the accumulation of dry matter and phosphorus in stems, leaves, glumes and rachis and their transfer to grains, and increase the number of spikes per unit area, grains per spike, 1000-grain weight and yield of winter wheat. For the highest winter wheat yield in the test area, the P₂O₅ application rate was 194.2‒197.4 kg/hm², and the soil available P was 25.5‒25.8 mg/kg.