Effects of different fertilization on loss of organic c and n in seepage water under phyllostachy pracox stand

Changes in dissolved organic carbon（DOC）and dissolved organic nitrogen（DON）concentrations in the seepage water from the soil under Phyllostachy praecox stand in the whole year were monitored to ascertain effects of reducing chemical and organic fertilizer rates on the reduced effects of the seepage loss of DOC and DON. The results showed that the average concentrations of DOC and DON in the seepage water for the different fertilization treatments were 33.7 mg/L ~45.5 mg/L and 4.3 mg/L ~13.8 mg/L, respectively, whereas the average seepage loss loads of DOC and DON for the different fertilization treatments were 84.5 kg/ha~138.2 kg/ha and 17.2 kg/ha~46.3 kg/ha, respectively. The seepage loss loads of DOC from the soil with different fertilization treatments decreased as follows: conventional fertilizer(CF) (138.2 kg/ha) decreased organic fertilizer(DO) (133.7 kg/ha) decreased inorganic fertilizer(DI) (120.9 kg/ha) no fertilizer （CK）(99.8 kg/ha) decreased organic inorganic fertilizer(DOI) (84.5 kg/ha), whereas the seepage loss loads of DON from the soil with different fertilization treatments decreased as follows: DO (46.3 kg/ha) CF (35.3 kg/ha） DOI (34.8 kg/ha)DI (31.1 kg/ha)CK (17.2 kg/ha). No significant relationship was found between DOC concentrations and DON concentrations in the seepage water. Under condition of that without reducing the bamboo yield, this experiment were set up with reducing nitrogen fertilizer rate of 40%. Compared with CF, DI and DOI could improve nitrogen fertilizer agronomic efficiency by 23.3%, 43.7%, respectively.