Nutrient Management Strategies for Guangdong

IPNI-2002-CHN-GD13

04 Feb 2008

2007 Annual Interpretive Summary

Nutrient Management Strategies for Banana in Guangdong, 2007

Banana is one of the most lucrative crops in southern China and is widely produced in the provinces of Guangdong, Guangxi, and Hannan where weather favors its growth. Due to its extremely high yield, fertilizer rates of K and N are particularly high and its nutrient uptake usually surpasses any other crop. Because of the high risk of large yield and economic losses, researchers and banana farmers in the past were always reluctant to conduct field trials that omit N and/or K or use check (CK) treatments supplying no fertilizers to study the contribution of indigenous soil fertility to banana production and its nutrient use efficiency. After repeated persuasion and encouragement, both local researchers and farmers finally agreed on a nutrient omission research plan. This work was conducted in Guangdong for the first time in China and aimed to further improve banana fertilizer recommendations and develop best nutrient management practices for banana production. The experiment consisted of four treatments, including the optimal treatment (OPT) including 900-270-108 kg N-P2O5-K2O/ha in 2006 and 825-247-990 kg/ha in 2007, as well as an OPT-N, OPT-P, and OPT-K.

Although all the nutrient omission treatments reduced banana growth, fruit yield, and quality, the losses were much less than what the researchers originally thought. Averaged over the 2 years, the OPT produced a fruit yield of 49 t/ha and a net income of US$10,953/ha. Yield and net income were reduced by 3.6 t/ha and US$550 for the OPT-N treatment. The OPT-P treatment reduced yield and income by 3.8 t/ha and US$1040/ha. The OPT-K treatment reduced yield and income by 6.4 t/ha and US$1,330. The OPT-P and OPT-K treatments significantly reduced plant height in both years. The OPT-K treatment delayed flowering by 47% and reduced single fruit weight by 12 to 14% in 2006/07. The OPT-P treatment significantly reduced the single fruit weight in 2007. No other significant differences were observed among the growth indices. Among the quality indices (i.e., soluble solids, soluble sugar, and vitamin C), there were no significant differences between treatments in 2006. In 2007, the OPT-N treatment significantly decreased vitamin C content and the OPT-K treatment significantly reduced both soluble sugar and vitamin C.

The results further suggest that fertilizer rates used for banana production in the past, N in particular, might be excessive as soil fertility has improved in recent years and should be re-examined and verified through field studies in the future. Guangdong-NMS-02