Evaluation of Nitrogen Fertilizer Supply and Soil Nitrate Thresholds for High Yields of Foxtail Millet
Yiwei Lu,
Yu Zhao,
Xueyan Xia,
Meng Liu,
Zhimin Wei,
Jingxin Wang,
Jianjun Liu,
Jihan Cui,
Shunguo Li
Affiliations
Yiwei Lu
National Foxtail Millet Improvement Center, Key Laboratory of Characteristic Grain Genetics and Utilization, Ministry of Agriculture and Rural Affairs, Hebei Coarse Cereal Research Laboratory, Institute of Millet Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050035, China
Yu Zhao
National Foxtail Millet Improvement Center, Key Laboratory of Characteristic Grain Genetics and Utilization, Ministry of Agriculture and Rural Affairs, Hebei Coarse Cereal Research Laboratory, Institute of Millet Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050035, China
Xueyan Xia
National Foxtail Millet Improvement Center, Key Laboratory of Characteristic Grain Genetics and Utilization, Ministry of Agriculture and Rural Affairs, Hebei Coarse Cereal Research Laboratory, Institute of Millet Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050035, China
Meng Liu
National Foxtail Millet Improvement Center, Key Laboratory of Characteristic Grain Genetics and Utilization, Ministry of Agriculture and Rural Affairs, Hebei Coarse Cereal Research Laboratory, Institute of Millet Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050035, China
Zhimin Wei
National Foxtail Millet Improvement Center, Key Laboratory of Characteristic Grain Genetics and Utilization, Ministry of Agriculture and Rural Affairs, Hebei Coarse Cereal Research Laboratory, Institute of Millet Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050035, China
Jingxin Wang
National Foxtail Millet Improvement Center, Key Laboratory of Characteristic Grain Genetics and Utilization, Ministry of Agriculture and Rural Affairs, Hebei Coarse Cereal Research Laboratory, Institute of Millet Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050035, China
Jianjun Liu
Hebei Academy of Coarse Cereal Industry Technology, Handan 056000, China
Jihan Cui
National Foxtail Millet Improvement Center, Key Laboratory of Characteristic Grain Genetics and Utilization, Ministry of Agriculture and Rural Affairs, Hebei Coarse Cereal Research Laboratory, Institute of Millet Crops, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050035, China
Shunguo Li
Hebei Academy of Agriculture and Forestry, Shijiazhuang 050000, China
Foxtail millet is an important cereal crop in the North China Plain. However, excessive nitrogen fertilizer application over the years has led to declining yield and soil quality. This study investigated nutrient management strategies for foxtail millet based on crop yield levels and soil nutrient availability. In a field where targeted fertilization was conducted over six seasons, nitrogen fertilization effects and the dynamics of soil-available nitrogen were monitored continuously for two consecutive years (2022–2023) across five different foxtail millet varieties with varying yield levels. The study aimed to determine the optimal nitrogen application rate for achieving a high yield of foxtail millet, the minimum soil nitrate threshold required to maintain soil fertility, and the effective nitrogen application rate range for sustaining soil-available nitrate levels. Results showed that fertilization significantly affected dry matter weight during flowering, while variety affected dry matter weight at maturity. The average nitrogen application rate for achieving high yield across all five millet varieties was 141.3 kg·ha−1. Specifically, the average nitrogen application rate of nitrogen-efficient varieties achieving high yield (5607.32–5637.19 kg·ha−1) was 151.5 kg·ha−1, while the average nitrogen application rate of nitrogen-inefficient varieties achieving high yield (4749.77–4847.74 kg·ha−1) was 134.5 kg·ha−1. Soil NH4+-N and NO3−-N content increased when nitrogen application rate exceeded 360 kg·ha−1, posing environmental risks. To achieve high yield, soil nitrate levels would be maintained at an average of 17.23 mg·kg−1 (before sowing) and 9.75 mg·kg−1 (at maturity). A relationship between soil nitrate and nitrogen application rate was established: y = 867.5 − 50z (where y represents the optimal nitrogen application rate for high yield (kg·ha−1), and z represents soil NO3−-N content in the 0–20 cm layer before sowing, ranging from 10.0 to 17.35 mg·kg−1), which provided a practical method for nitrogen fertilization to achieve high yield of foxtail millet. In this study, the fertilization strategy was optimized according to soil nutrient level and yield targets, and the nitrogen application rate was controlled within 360 kg·ha−1 based on the soil nitrate nitrogen content, which will be instructive for reducing fertilizer use, maximizing fertilizer efficiency, and increasing yield.
