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


30 Jan 2007

2006 Annual Interpretive Summary

Effect of Balanced Fertilization on Yield and Quality of Chinese Cabbage and Lettuce in Chongqing, 2006

The objective of this project was to employ balanced fertilization (BF) technology to improve yield and quality of vegetables for residents of the Chongqing Autonomous City. Two leafy vegetables, Chinese cabbage and lettuce, were selected for study. The experiments consisted of nine treatments: two rates of N, P, and K, one rate of boron (B), two types of manures (rapeseed meal and peat), and a zero fertilizer check. The treatment with 225-75-150 kg N-P2O5-K2O/ha was also used as a check (CK).

Compared to the CK, cabbage yield was most improved through further addition of either 2,250 kg peat/ha (+17.0 t/ha, or 42%) or 2,250 kg rapeseed meal/ha (+17.4 t/ha, or 43%). Further addition of either 75 kg N/ha, 75 kg P2O5/ha, 75 kg K2O/ha, or 0.9 kg B/ha was much less effective, but did increase yield by 6.7 t/ha (17%), 9.6 t/ha (24%), 13.3 t/ha (33%), 10.3 t/ha (26%), respectively. All improved treatments, except those adding P and K, increased vitamin C, reducing sugars, and amino acid contents. Despite these yield improvements, tissue nitrate contents were all over 2,000 mg/kg, excluding the zero fertilizer treatment.

Using the same treatments applied in cabbage, lettuce yield increased by 4.0 t/ha (26%), 5.4 t/ha (36%), 2.6 t/ha (17%), 0.7 t/ha (4.6%), 5.3 t/ha (35%), and 8.4 t (56%) with further addition of N, P, K, B, peat, or rapeseed meal, respectively. Application of these treatments under consecutive lettuce cropping resulted in dimishing returns from these enhanced treatments. Rapeseed meal was most effective at sustaining long-term responses. Compared to the CK, all other treatments had slightly less vitamin C, reducing sugars, and amino acid contents. Nitrate content, however, measured far below the risk level for lettuce. Chongqing-BFDP-SU06