The results showed: Under normal fertilization conditions, the application of 20 mg/kg γ-PGA could significantly increase the chlorophyll and the fresh quality of the underground parts of pakchoi, and the maximum increase in the fresh mass of the aboveground parts of pakchoi reached 8.6%.
At the same time, it can also significantly increase the content of ammonium nitrogen in the soil, and the nitrogen use efficiency can increase by 10.6%. Compared with the control group, the application of 20 mg/kg γ-PGA can reduce the nitrate content in the pakchoi by 44. 8%, increase the vitamin C (Vc) content by 18. 1%, and achieve the best quality of pakchoi.
We applied 20 mg/kg γ-PGA could increase the utilization rate of nitrogen fertilizer by 10.2% ~ 11.6% under conditon of reducing of 15% nitrogen fertilizer.
It shows that γ-PGA has a significant effect on improving the yield and quality of pakchoi in the absence of fertilizers.
Field Trial
Table 1 Test Plans | ||
Treat | Process Mode | γ-PGA Additive Amount (mg) |
Group 1 | Urea + Basic Fertilizer | 0 |
Group 2 | Urea + Basic Fertilizer + γ-PGA | 20 |
Group 3 | 85% Urea + Basic Fertilizer + γ-PGA | 20 |
Table 2 Effects of γ-PGA on Growth Characteristics | ||||
Treat | Plant Height (cm) | Chlorophyll CCI | Underground Part Fresh Weight (g) | Overground Part Fresh Weight (g) |
Group 1 | 11.3 | 49.1 | 3.2 | 52.4 |
Group 2 | 12.0 | 52.0 | 3.5 | 56.9 |
Group 3 | 11.6 | 55.6 | 3.4 | 54.6 |
Table 3 Effects of γ-PGA on nitrogen use efficiency | |||
Treat | Total Nitrogen (g/kg) | Nitrogen Uptake (mg/Pot) | Nitrogen Use Efficiency (%) |
Group 1 | 39.4 | 341.1 | 36.3 |
Group 2 | 41.6 | 367.6 | 43.3 |
Group 3 | 32.1 | 353.2 | 46.5 |
Conclusion
The application of γ-PGA is of great significance for improving fertilizer utilization rate, reducing fertilizer loss, improving crop quality and realizing sustainable agricultural development.