Objective  Derived from fertilization models, utilization of organic fertilizers to partially replace NPK for peanut farming in Fujian was investigated.

  Method  In the major peanut producing areas in Fujian, 105 field experiments were conducted in recent years to examine the response of peanut plants to NPK fertilization. Applying the systematic cluster analysis combined with significant test of difference, various fertilization categories for the planting fields were established. A ternary non-structural fertilizer response model was constructed to arrive at recommend fertilizations for each category. Based on the models, field experiments were carried out to test replacement of NPK with an organic fertilizer.

  Result  According to the significant differences on effectiveness of NPK fertilizations, 4 categories of peanut fields were generated as (1) high yield paddy, (2) medium yield paddy, (3) medium-to-low yield field, and (4) low yield field. To maximize the fertilization effect and peanut yield for the fields, 4 optimized models were formulated to obtain the recommended NPK applications. In 34 controlled field experiments, on average, a 10.2% yield increase over the conventional practice was realized by following the recommendation of the models. Meanwhile, although the usage of N decreased 24.9% and of P 38.1%, that of K increased 79.3%. Financially, the cost on fertilizer was reduced to 63 yuan·hm⁻² and the net revenue increased to 2 877 yuan·hm⁻². Furthermore, by replacing 25% of NPK with a commercial organic fertilizer resulted in the highest peanut yield among all treatments. The substitution increased peanut yield by 10.6% and revenue by 1 595 yuan·hm⁻²over the recommended NPK application.

  Conclusion  It appeared that a 25% replacement of NPK with the organic fertilizer based on the recommended fertilization could be most profitable for the peanut farming in Fujian.