Nutrient management increases potato productivity and reduces environmental risk: Evidence from China

Abstract

In the absence of a robust nutrient recommendation methodology for smallholder farmers in China, fertilizers are being over-applied to potato fields, which not only threatens potato production, but also causes environmental pollution. To address these challenges, the Nutrient Expert (NE) for Potato was developed based on a large database collected from field experiments. The tool analyzes the real scenarios in different ecological regions and provides tailored calculations of the nutrients needed to achieve the expected yield and agronomic benefits. The method was tested and validated in 239 field trials compared with current farmers' practices (FP) and soil test (ST) based fertilizer recommendations. Results showed that to produce 1000 kg tuber yield when achieved 80% potential yield, plants in the south region required 5.68, 0.79, and 6.64 kg of nitrogen (N), phosphorus (P), and potassium (K), and in the north region required 4.93, 0.74, and 5.35 kg of N, P, and K, respectively. The correlation between yield response and agronomic efficiency was in accordance with a quadratic curve. Soil indigenous N, P, and K supply contributed 68.5%, 83.1%, and 78.9% to the total tuber yield in the south region, while 75.0%, 84.0%, and 83.5% in the north region, respectively. Field validation showed that the NE recommended 24.4% and 4.2% less N fertilizer, 32.3% and 1.9% less P fertilizer, and 4.9% and 4.9% more K fertilizer compared to the FP and ST, respectively. The tuber yield and profit with the NE method were 9.0% and 8.9% more than those with FP, and 1.9% and 1.6% more than those with the ST, respectively. In addition, the greenhouse gas (GHG) balance was 14.8% and 2.0% less and GHG intensity was 24.6% and 3.3% less for the NE compared to the FP and ST, respectively. The results suggest that by adopting the NE method for the fertilizer recommendations, farmers can achieve better potato yields and economic benefits while reducing environmental risks.