Nutrient Management for Litchi in Guangdong

Application ratio of N/K2O

IPNI-2009-CHN-GD12

14 Jan 2013

2012 Annual Interpretive Summary


Litchi is one of the most favorable subtropical fruits grown in China. To get high yields and quality of litchi, special care is needed for its mineral nutrition. Among all the essential nutrients, insufficient or over supply of N or K, or using improper fertilizer ratios of K2O/N, usually reduces litchi yield and quality. High fertilizer K2O/N ratios are known to cause fruit cracking, which results in economic loss to the growers. We conducted a three-year field experiment to determine the optimal fertilizer ratios of K2O/N for litchi production in Guangdong. Treatments included five K2O/N ratios (0.6, 0.8, 1.0, 1.2, and 1.4) with five replications (trees). Each tree received a total amount of 0.36, 0.48, 0.60, 0.72, or 0.84 kg K2O in combination with a fixed rate of P, Ca, Mg, Zn, B, and Mo based on soil testing. Nitrogen, P, K, Ca, and Mg were split applied at four times, viz., at after-harvest, before-blossom, after-blossom and fruit swelling stages, and the micronutrients were applied at after-harvest stage only.

Results showed that litchi yield increased slightly, but consistently with an increase in K rate and leveled off at 0.72 kg K2O/tree, i.e., a K2O/N ratio of 1.2 in three years. At this ratio, the single fruit weighed 7 to 10% more than the lowest K treatment and 8 to 9% more than the highest K treatment. The photosynthesis rate, anti-oxidation activity of the leaves, growth rate, fruit quality, and economic returns were maximum at K2O/N ratios of 1.0 to 1.2. In summary, a K2O/N ratio of 1.0 to 1.2 can be recommended for high yield and quality of litchi in Guangdong. Guangdong-BFDP-09