Establishing phosphorus and potassium fertilization recommendation index based on the ‘3414’ field experiments

Recently, numerous field experiments are conducted in national soil testing and fertilization recommendation project, however, how to use these experimental data to establish fertilization recommendation index is urgently needed. Taking the winter wheat “3414” experiments in Shandong Province as an example, the process of establishing fertilization recommendation index was investigated and discussed. Soil Olsen-P and NH4OAc-K were classified as low (75% relative yield), medium (75%–90% relative yield), high (90%–95% relative yield) and very high (95% relative yield) based on the relative yields. Fertilizer recommended rates were simulated by the models of three-factor or one-factor for each “3414” field experiment. The results indicate that phosphorus fertilizer rates (P2O5) are 100–130, 80–100, 60–80, and 0 kg/ha when soil fertility are classified as low, medium, high and very high (Olsen-P10, 10–30, 30–50 and 50 mg/kg), respectively, while potassium fertilizer rates (K2O) are 120–150,100–120, 60–80, and 0 kg/ha (NH4OAc-K 50, 50–100, 100–140 and 140mg/kg). Therefore, establishing fertilization recommendation index based on "3414" field experimental data is practicable.