Fertilizer recommendation based on Nutrient Expert system to improves pear yield and quality

Objectives  The Nutrient Expert System recommends fertilization based on yield response and agronomic efficiency, which is simple and easy to implement. In this study, we applied this method to optimize recommended fertilization for pear trees and verified the practicability of this method using field trials.

Methods  We conducted a 3-year fertilization experiment in Baoding City, Hebei Province, China, from 2017 to 2019 using the Chinese pear variety, Huangguan (Pyrus bretschneideri Rehd. var. Huangguan) as test material. The three fertilization regimes evaluated in this study were Nutrient Expert (NE), farmers’ practice (FP), and soil test (ST). We measured the leaf and fruit nitrogen (N), phosphorus (P) and potassium (K) concentrations, fruit yield and quality, fertilizer agronomic efficiency and partial productivity, and economic returns.

Results  Compared to FP, N, P and K fertilization rates in NE treatment decreased by 35.96%, 28.8% and 57.92%, respectively. Compared with FP treatment, the nitrogen and phosphorus content in leaves under NE treatment was increased by 8% and 26% on average in three years; the nitrogen, phosphorus and potassium content in fruits incrensed by 26%, 68% and 18% on average in three years. Under NE treatment, the average maximum yield and market value of pear fruits were 45.80 t/hm² and RMB 186100 yuan/hm². The fruit yield under NE treatment increased by 15.56%–26.91% and 10.24%–15.23% compared with FP and ST fertilization treatments. The economic benefits of NE treatment were increased by 17%–29% and 11%–16% compared with those of FP and ST fertilization. The average soluble sugars and ratios of soluble solids/titratable acids in 2017–2019 were significantly increased by 27% and 10% under NE treatment than FP treatment, and there was 21% higher soluble sugars under NE treatment than ST treatment. However, titratable acids, soluble solids were similar among FP, NE and ST treatments. Meanwhile, compared with FP, the agronomic efficiency and partial factor productivity of N, P and K fertilizers under NE treatment were increased by 13.76, 19.95, 24.07 g/kg and 36.52, 42.21 and 76.81 g/kg, respectively.

Conclusions  Our findings show that recommending fertilization based on the Nutrient Expert System can increase the yield response and agronomic efficiency of pear fruit plantations. We show that the Nutrient Expert System increased the yield, quality, fertilizer utilization and economic benefit of pear production, indicating that the optimized fertilization program is suitable for pear production in Hebei Province. However, in the recommended scheme, further research is needed to determine if inorganic fertilizers can substitute for organic fertilizers and whether soil nutrient balance can be maintained for a long time.