Meta-analysis of the Effect of Nitrogen Fertilizer Application on Potato Yield Increase and Its Influencing Factors

Purpose To quantitatively analyze the factors influencing potato yield increase under nitrogen fertilization in China.

Methods Based on publicly available field experiment data, with no nitrogen application as the control, a quantitative study was conducted using Meta-analysis to investigate the effects of geographical factors (region, altitude, soil pH), climatic factors (annual precipitation, annual average temperature), and field management measures (planting density, nitrogen application rate) on the yield-increasing effect of nitrogen application in potatoes.

Results The results of different studies exhibited significant heterogeneity. According to the analysis using the fail-safe number method, there was no publication bias in this study. Compared to no nitrogen application, nitrogen application could significantly increase potato yield by 37.4% (P<0.01). The yield-increasing effect of nitrogen application on potatoes was highest in the Southwest area, with a yield increase rate of 59.8%, followed by the North China (49.2%), the Northeast (44.3%), and the Southeast (42.9%) area, and the lowest in the Northwest area (29.8%). When the altitude was less than 850 m, the yield increasing rate of nitrogen-fertilized potatoes was 44.3%, and the rate decreased with increasing altitude. When the pH value was from 6.5 to 7.5, the yield increase rate of nitrogen-applied potatoes was the highest (44.9%). The yield-increasing effect of nitrogen fertilization on potatoes increased with the increase of precipitation and annual average temperature, and exhibited a trend of first increasing and then decreasing with the increase of planting density and nitrogen application rate. When the planting density was from 5.25×10⁴ to 6.75×10⁴ plant/hm² and the nitrogen application rate was from 120 to 180 kg/hm², the effect of nitrogen application on increasing potato yield was the most pronounced.

Conclusion The yield-increasing effect of nitrogen application on potatoes is closely associated with external factors such as geography, climate, and field management practices. The research results can provide a reference for nitrogen application techniques in potato cultivation in China.