Impact of reduced fertilization and fertigation on growth and nutrient demand of Astragalus membranaceus seedlings

【Objective】Following China’s mandate for zero growth in fertilizer use in agricultural production, improving fertilizer and irrigation water efficiency has become a key priority for sustainable agriculture. Astragalus mongholicus is an important medicinal herb grown in Northwestern China. This study investigates how reducing fertilizer application combined with fertigation (integrated fertilization and irrigation) influences the growth and yield of Astragalus mongholicus.【Method】The experiment was conducted on sandy soil in Horqin, Inner Mongolia, focusing on Astragalus mongholicus seedlings. It included five treatments: conventional fertilization combined with spraying irrigation (CS), conventional fertigation (CW), conventional fertigation with a 30% nitrogen reduction (TW), and conventional fertigation with a 50% nitrogen reduction (FW). During the experiment, plant growth parameters and fertilizer requirements were measured for each treatment.【Result】① Fertigation significantly improved plant growth traits, particularly root length and fresh root mass. ② Between 83 and 118 days after seedling emergence, the plant exhibited the fastest dry matter accumulation and the highest demand for phosphorus and potassium absorption. ③ Compared to conventional fertilization combined with micro-spraying irrigation, reducing nitrogen application by 30% combined with fertigation increased nitrogen and phosphorus use efficiency, crop yield by 15.93%, and water use efficiency by 33.33%, leading to a net income increase of 32 648.26 yuan/hm2.【Conclusion】Our results provide valuable insights for optimizing nitrogen, phosphorus, and water application in the intensive and sustainable cultivation of Astragalus mongholicus in the studied region.