Objective  To study the characteristics of nitrogen(N), phosphorus(P) and potassium (K) nutrient release and soil N, P, K nutrient balance under straw mulching pattern during potato planting process.

Method  We studied the decomposition rate and nutrient release status of mulching straw using pot experiment.

Result  Straw carbon (C) and P contents changed slightly after mulching for 82 days, while K content decreased by 93.96%, and N content increased by 49.22%. The mulching straw provided a large amount of nutrients (especially K) with 100 kg mulching straw contributing 0.42 kg N, 0.14 kg P (P₂O₅), and 1.70 kg K (K₂O) to soil used for potato growth. Straw decomposition rate was 70.87%. The nutrient accumulative release rates were performed as: K (98.22%) > C (71.89%) > P (68.75%) > N (56.85%). Straw mulching and K fertilization largely affected soil K balance. The K deficient amount was 163.80 kg/hm ² without straw mulching and K fertilizer application. K deficient amount was effectively reduced by straw mulching and K fertilization, and even K had surplus with combined application of straw and K fertilizer.

Conclusion  The straw mulching pattern can reduce K fertilizer application amount and production cost, and relieve the dilemma of K fertilizer resource deficiency in China.