Abstract: To provide a scientific basis for corn potassium (K) fertilization,the abundance-deficiency index(ADI) of soil available K for corn(SAKFC) and the appropriate K fertilizer application rates(APFAR) for corn in the Northeast plain,the Huang-huai-hai plain,the loess plateau,the northwest desert oasis area,and the southwest hilly area were studied.The methods of scattered theoretical data integration,regression equation between relative yield in the absence of K fertilizer and soil available K content,and the new applied formula based on “nutrient balance and projected yield minus soil fertility yield” for determining the appropriate fertilizer application rates were employed.The results showed that the ADI of SAKFC in the Northeast plain for the first to fifth level was≥167,121-167,63-121,33-63 and<33 mg/kg,respectively.The ADI of SAKFC in the Huang-huai-hai plain for the first to the fifth level was≥176,112-176,46-112,19-46 and<19 mg/kg,respectively.The ADI of SAKFC in the southwest hilly area for the first to the fifth level was≥186,124-186,55-124, 24-55 and<24 mg/kg,respectively.The ADI of SAKFC in the loess plateau for the first to the fifth level was≥269,187-269, 91-187,44-91 and <44 mg/kg,respectively.The ADI of SAKFC in the northwest desert oasis area for the first to sixth level was≥205,166-205,110-166,73-110,48-73 and<48 mg/kg,respectively.When the K fertilizer use efficiency in the current season was 50%,the APFAR for grain corn(target yield of 6-15 t/hm^2) for the first to the sixth level was 0,25-63,50-126, 76-189,101-252 and 126-315 kg/hm2,respectively.The APFAR for silage corn(target yield of 30-120 t/hm^2) for the first to the sixth level was 0,21-84,42-168,63-252,84-336 and 105-420 kg/hm^2,respectively.

Key words: China;Corn;Soil testing and fertilizer recommendation;Available K;Abundance-deficiency index;Fertilizer application rate