Effect of balanced fertilization on yield and quality of Chinese cabbage and lettuce in Chongqing


04 Feb 2008

2007 Annual Interpretive Summary

Effect of Balanced Fertilization on Yield and Quality of Chinese Cabbage and Lettuce in Chongqing, 2007

The project was initiated in 2006 to examine the effect of different fertilizer treatments on yield and quality of consecutively planted leafy vegetables, Chinese cabbage, and lettuce, in the suburb of Chongqing Autonomous City. The results will be used to guide fertilizer application and nutrient management in the suburb, and similar areas under intensive vegetable cultivation. The experiments consisted of nine treatments with two rates of N, P, and K, one rate of boron (B), two types of manures (rapeseed meal and peat), and a zero fertilizer treatment. A common farmer practice (FP) treatment of 225-75-150 kg N-P2O5-K2O/ha was also used. Each vegetable was grown for three seasons in 2007.

Compared to the FP treatment, yields of both cabbage and lettuce increased with further addition of 75 kg N/ha, 75 kg P2O5/ha, 75 kg K2O/ha, 0.9 kg B/ha, 2,250 kg peat/ha, and 2,250 kg rapeseed meal/ha. Addition of these nutrient amounts increased cabbage yield by 14% to 15% for N, 20% to 34% for P, 26% to 46% for K, 14% to 26% for B, 35% to 61% for peat, and 47% to 69% for rapeseed meal. The effects of the treatments on cabbage quality were somewhat different from the previous year. That is, additional N enhanced nitrate and amino acid content in leaf tissue and added P increased vitamin C. There were no certain quality trends observed for the other treatments.

Using the same treatments as were applied in cabbage, first season lettuce responded poorly to the further addition of N and B, leading to yield reductions of 16% for N and 5% for B. For the second and the third seasons, lettuce yields were increased by 18 to 53% for N, 36 to 47% for P, 26 to 48% for K, 11 to 33% for B, 34 to 91% for peat, and 40 to 70% for rapeseed meal. It is apparent that lettuce was much less responsive to B than Chinese cabbage. Consecutive lettuce cropping responded more effectively to the enhanced fertilizer treatments than the previous year. No consistent quality trends were observed for lettuce amongst treatments in 2007. Nitrate contents in lettuce tissue were far below the risk level. Rapeseed meal and peat appeared to be good amendments for lettuce and cabbage as both provided a superior yield response compared to further addition of any mineral nutrient, and they also significantly improved fertilizer use efficiency for N, P, and K. Chongqing-BFDP-SU06