Citrus

1. Stress Resistance (various enzyme activities, phenotypes of different organs)

Treatment: Two treatments were set up in the experiment, namely CK (0g/L) and FA-K (1.5g/L), applied to two batches of citrus seedlings that were basically similar for salt stress treatment. After the stress was observed, spraying treatments were carried out continuously for three days, while other conventional operations were performed.

Figure11.The growth status of citrus seedlings under various treatments during salt stress.

Table2. Soil enzyme activity under different treatments

Results: Compared with the control, fulvic acid treatment can significantly enhance various soil enzyme activities under salt stress, promote the decomposition of soil nutrients into smaller molecules that are more easily absorbed by roots, thereby maintaining tree vigor and ensuring survival.

2. Biomass (growth of each organ)

Treatment: Two treatments were set up in the experiment, namely CK (10g of urea per week) and HA (10g per week), applied to two batches of citrus seedlings that were basically the same,while other operations were carried out conventionally.

Figure12. Plant growth under different treatments

Result: Compared with the control, applying humic acid promoted stronger growth in young citrus trees.

3. Fruits (yield, coloration, internal quality (nutritional components))

Treatment: Two treatments were set up in the experiment, namely CK (KH2PO4 0 g/L) and FA-K (1.5 g/L). Two batches of citrus trees with similar conditions were selected. After the physiological fruit drop was completed, fertilization was applied once a week, while other operations followed conventional practices.

Figure13. Fruit growth under different treatments

Result: Compared with the control, fulvic acid significantly increased the sucrose, glucose, and fructose content of the fruit, and promoted fruit coloring.