Abstract:

The aim of this study is to establish the abundance-deficiency indexes of NPK of upland wheat in Yunnan and recommend proper fertilizer amounts. According to experiment data of recent ten years, the correlation between the contents of soil available NPK and the yield of wheat was analysed. For nutrient deficiency area, based on the relative yield of wheat>90%, 75%-90%, 60%-75% and<60% in comparison to the yield of best fertilization wheat area, we classified corresponding soil fertility into 4 levels, namely high, medium, low and very low, established the abundance-deficiency indexes and recommended fertilizer amounts for wheat production. The results showed that the average amount of alkali-hydrolyzed N, available P and available K was 145.3, 26.6 and 143.0 mg/kg, respectively, in upland wheat field of Yunnan, and the variation of all the three nutrients was relatively large. When alkali-hydrolyzed N in soil was high (>175 mg/kg), medium (155-175 mg/kg), low (125-155 mg/kg) and very low (<125 mg/kg), the recommended nitrogen fertilizer rate (N) was 25-45, 45-115, 115-185 and 185-210 kg/hm², respectively. When available P in soil was high (>30 mg/kg), medium (15-30 mg/kg) and low (<15 mg/kg), the recommended phosphorus fertilizer rate (P₂O₅) was 15-30, 30-75 and 75-110 kg/hm², respectively. When available K in soil was high (>145 mg/kg), medium (85-145 mg/kg) and low (<85 mg/kg), the recommended potassium fertilizer rate (K₂O) was 15-30, 30-75 and 75-110 kg/hm², respectively. The results of this study can provide reference for proper fertilization on upland wheat in Yunnan Province.

Key words: upland wheat, yield, nutrient, abundance-deficiency index