Abstract:Based on agricultural economy statistical data, the model of farmland nutrient balance of input/output and GIS, the balance characteristic of farmland potassium nutrient and its spatial distribution in China in 2000 was studied. The conclusions were as follows: 1) the total input of potassium for farmland was 1.068 ×107 t in China, but the output was 1.458 ×107 t, with a deficit of 3.90 ×106 t (40 kg/hm2), 2) at county level, 77.39% of the counties in China showed a deficit supply of potassium, 3) in the total input of potassium for farmland, the chemical potassium fertilizer amounts to 4.77 ×106 t and the organic potassium fertilizer to 4.98×106 t, 4) at national scale, the potassium provided by the excrement and urine of human and animals and the crop straw occupy 48.98% and 51.02% of the total potassium supply, respectively, 5) the biological output of potassium from national farmland amounts to 1.335×107 t, was 91.56% of the total expenditure.