Current situation and reduction potential of potato fertilization in China

Objectives Reasonable fertilization is required for the high yield, quality and profit of potato production. We investigated the fertilization situation of the main potato production areas around China, and the localized potential of fertilizer reduction.

Methods A total of 1807 potato fields in the main potato producing areas were surveyed during 2019−2021 in China. The questionnaire included potato yield, fertilizer sources and ratios of nitrogen (N), phosphorus (P) and potassium (K) fertilizers, and the frequency of basal dressing and topdressing. The fertilizer nutrient reduction potential was evaluated using the fertilizer recommendation rate produced by Nutrient Expert (NE) system.

Results On average across China, the annual total N, P₂O₅ and K₂O input for potato was 252, 219, and 224 kg/hm², respectively. N 187 kg/hm², P₂O₅ 164 kg/hm² and K₂O 175 kg/hm² were from chemical fertilizer, and the left from organic fertilizer. The organic nutrients accounted for 25.8%, 25.6%, and 21.4% of the total N, P₂O₅ and K₂O inputs. Compound fertilizer was the main chemical fertilizer source in the surveyed potato fields, supplied 84.6%, 95.7% and 92.8% of chemical N, P₂O₅ and K₂O nutrients. And 82.9% of organic fertilizer was from livestock and poultry manure. Compared with the fertilizer rate recommended by NE system, the fertilizer nutrient reduction potential across China was about 47.0%, of which the N, P₂O₅, and K₂O reduction potential in the monocropping area of North China were 17.8%, 54.8%, and 55.2%; the P₂O₅ and K₂O reduction potential in the monocropping area of Northeast China were 64.6%, and 46.9%, respectively; the N, P₂O₅, and K₂O reduction potential in the monocropping area of Northwest China were 17.3%, 47.7%, and 21.5%, respectively. The reduction potential of N, P₂O₅, and K₂O were 7.4%, 51.6%, and 18.3% in the mono/two cropping area of Southwest China, and 31.1%, 69.7%, and 61.2% in winter season area of South China, respectively.

Conclusions The nutrient inputs in potato is generally high and unreasonable in nutrient ratios, particularly the low proportion of organic fertilizer nutrients. The promotion of the Nutrient Expert recommendation will save 47.0% of current fertilizer nutrient input in China, the reduction rate of N, P₂O₅, and K₂O nutrient is dependent on the cropping system, production areas, and fertilization method.