Abstract: We examined the effects of 30% reduction of chemical fertilizer replaced by adding different organic fertilizers (chicken manure organic fertilizer, vermicompost from pig manure, and vermicompost from kitchen waste) on the growth, yield and grain quality of sweet-waxy corn, aiming to choose proper strategy of using organic fertilizer to replace chemical fertilizer in sweet-waxy corn planting. Sweet-waxy corn Nongkeyu 368 was used as test crop. There were six treatments, including no fertilizer treatment (CK), fullquantity fertilizer application (CF), reduced fertilizer application (RF), reduced fertilizer combined with chicken manure organic fertilizer (RF+OF), reduced fertilizer combined with vermicompost from pig manure (RF+PF), andreduced fertilizer combined with vermicompost from kitchen waste (RF+KF). The growth and photosynthetic characteristics of corn were measured at the jointing stage and tasseling stage respectively, while the yield and quality (including heavy metal content) of the grain were measured during the harvest period. The corn yield under the treatments of RF+KF and RF+PF was similar to that under CF treatment. Compared with CF treatment, the number of spikes of RF treatment was significantly decreased while the yield was not significantly different. The plant height, stem diameter and leaf chlorophyll content followed the sequence of CF ≥RF+KF > RF > RF+OF > (RF+PF). Compared with CF treatment, photosynthetic rate was significantly lower under RF+PF treatment, and intercellular CO₂ concentration of RF+KF was significantly higher. Fertilizer application significantly increased the contents of vitamin C, soluble protein, and starch in corn grains. Compared with CF treatment, reduced fertilization with application of organic fertilizer significantly increased vitamin C content, with the maximum under RF+KF treatment. The soluble protein content was significantly higher under RF+PF treatment. The soluble sugar contents were significantly higher under RF+OF and RF+KF treatments, with an enhancement of42.07% and 69.01%, respectively. The starch content was significantly higher under RF+KF treatment. Fertilization treatment significantly increased Zn content in the corn grains, but did not affect Cd and Pb contents. The maximum accumulation of Zn, Cu, and Cr was found under RF+OF treatment. In conclusion, corn yield under RF+PF and RF+KF treatments was similar to that under full-quantity fertilizer treatment. RF+KF treatment improved fruit quality, and thus is a feasible strategy for fertilizer reduction in corn production.

Key words: reduced fertilizer application, sweet-waxy corn, vermicompost, corn yield, corn quality, heavy metal.