The effects of ploy (γ-glutamic acid) on spinach productivity and nitrogen use efficiency in North-West China

Recently, with the problem of low utilization rate of nitrogen fertilizers in farmland, agriculture practices have shifted towards the development of environmentally friendly nitrogen fertilizers. Ploy (γ-glutamic acid) is a new plant growth regulator with characteristics of water and fertilizer conservation. In this study, pot experiments were conducted to investigate the effects of ploy (γ-PGA) on the yield, nitrogen use efficiency and soil aggregate of spinach (Spinacia oleracea L.). The results indicated that γ-PGA (0.1%) increased plant growth (as measured by fresh and dry plant weight). However, increasing γ-PGA significantly decreased spinach quality parameters. The nitrogen utilization and use efficiency were increased with increasing γ-PGA. Ploy was stronger in water coagulation which effectively increased soil porosity and improved soil structure. The results suggest that 0.1% of γ-PGA has positive effects on spinach growth.