Studies and Demonstration on Environmentally Sound Fertilization Technology for Vegetables and Banana

Vegetable planting area in Fujian Province has reached 670,000 ha with a total production of 14,530,100 t, and is valued at USD 33 billion. However, imbalanced fertilization practices usually followed by farmers here affect the environment negatively. This study was conducted by the Soil and Fertilization Institute of Fujian Academy of Agricultural Science with the objectives of demonstrating efficient fertilization technology for vegetables and banana in Fujian.

Results showed that balanced fertilization helped attain maximum lettuce yield of 46 t/ha (8.7% increase over farmers’ practice) with net income of USD 1,509/ha. For banana, the results showed that average yield of balanced fertilization plots was 43.8 t/ha. Nitrogen fertilization contributed banana yield 0.8 to 4.2 t/ha, P fertilization contributed 0.2 to 4.4 t/ha and K fertilization contributed 1.2 to 3.8 t/ha over farmers’ practice. A control plot without fertilizer revealed that soil indigenous nutrient supplies contributed about 50% of banana yield.

A long-term field experiment has been running in Pinghe county since 2008 with green beans-cucumber-early rice rotation. Unfertilized plots showed that the soil indigenous fertility contributed about 61% to vegetable yield and about 80% to rice yield. The residual effect of N and P fertilizers applied to the two vegetable crops in rotation, had a positive impact on the yield of early rice yield. No fertilization in the rice growing season obtained the highest economic profit with less than 10% lower yield, reflecting the large supply of residual nutrients left after the two vegetable crops. After cucumber, soil NO₃^--N and P concentrations of soil water were 1,125 mg/L and 2.267 mg/L, and after rice planting season, it dropped to 143.5 mg/L and 0.435 mg/L. Therefore, in this rotation, rice planting not only greatly increased fertilization efficiency, but also greatly reduced the NO₃^--N and P concentrations of soil water. In this rotation with optimum fertilization treatment, N loss was reduced by 67.7 kg/ha and N use efficiency increased from 45.1 to 65.6%, while P loss reduced by 6.6 kg/ha and P use efficiency increased from 17.9 to 26.5% over farmers’ practice. Fujian-10