Figure 3
Temporal variations of soil NH4 +-N (a), NO3 −-N (b), Olsen-P (c), available K (d) content and pH (e). Error bars represent standard error (n = 3). CK: Normal fertilization with no γ-PGA application, γ-PGA: Normal fertilization with application of 350.44 mg γ-PGA kg−1 soil. **p < 0.01, *p < 0.05.
