Nutrient Content and Ratio in Litchi Leaves in Fall
Two-year fertilizer trails on quality litchi (Guiwei and Luomici) were conducted in the litchi plantations located in Shengzhen City, Dongguan City and Huadu District of Canton in Guangdong province. All the treatments and fertilizer rates used in the trials are given in Table 1. Results showed that the nutrient content in mature leaves of fall branches was in the order of N > K > Ca > Mg > P, S (Table 2). Under the conditions where K, Mg, and S were deficient, balanced fertilization increased the content of K, Mg, and S by 10-12%, 7-15%, 6-14% in the leaves compared to farmers’ practice. These improved nutritional conditions favoured litchi growth and improved crop tolerance for harsh weather.

Table 1 The rate of fertilizers used per year for litchi in different treatments (g/plant)



Table 2 Nutrient content and ratio in mature Guiwei and Nuomici leaves in fall



Nutrient Content and Ratio in Fruits
Nutrient content varied greatly in the different parts of litchi fruit (Table 3). Potassium appeared to be the highest in the pulp and the pericarp of fruit which was followed by N. The contents of nutrient tested were in the order of K > N > P > Mg, S > Ca in the pulp and K > N > Ca > Mg > P > S in the pericarp.

Table 3 Nutrient content and its ratio in the different parts of litchi fruit (1999-2000)

All the data came from balanced fertilization with NPKMgS treatment. The pulp was sampled fresh and the pericarp and seed were dry.


Comparing the two litchi varieties, they differed considerably in nutrient content in the fruit and fruit yield (Table 4). It appears that the higher the nutrient uptake, the higher the fruit yield. In terms of nutrient per unit fruit weight; however, the Guiwei variety required higher quantity of nutrients to produce the same fruit yield than the Luomici (Table 5).

Table 4 Yield and nutrient uptake in litchi fruits for Guiwei and Luomici



Table 5 Nutrient uptake in 100 kg of litchi fruits and the nutrient ratio



Yield and Economic Profit from the Different Treatments
The yield and economic profit from litchi varied in the different treatments (Table 6 and 7). Balanced fertilization with NPKMgS proved to be the best and produced the highest yield of 20,685 kg/ha and highest economic profit of US$ 20,978/ha. It increased litchi yield by 7,620 kg/ha and net profit by US$ 8,455/ha compared to farmers’ practice. The balanced fertilizer treatment is highly recommended to litchi growers and its extension has been in good progress in Guangdong province.

Table 6 Agronomic properties of quality litchi as affected by different treatments

Treatment	Fruit weight (g/fruit)	Fruit diameter (cm)	Fruit height(cm)	Yield of a litch tree(kg)	Total yield (kg/ha)
Farmers’ practice	18.8	3.33	3.21	39.6	13,065
NPMgS	19.1	3.34	3.23	45.6	15,045
NPKS	18.8	3.31	3.24	47.0	15,510
NPKMg	19.0	3.33	3.21	49.8	16,440
NPKMgS	19.8	3.45	3.38	62.7	20,685

Note: total yield is the average of Guiwei and luomici in two years. LSD 0.05=3,570 kg/ha, LSD=4,890 kg/ha.



Table 7 Effect of different fertilizer treatments on profit of litchi

Note: the fertilizer prices used in profit calculation: urea $US 158.6/t, super single phosphate $US 48.8/t, imported DAP $US 268.2/t, KCl $US 171/t, MgCl2 $US 158.6/t, compound fertilizer (15-15-15) $US 280.4/t, SPM $US 158.5/t, S $US 304.9/t. Wholesale litchi price: $US 1.1/kg.


Besides the increase in litchi yield and economic return, balanced fertilization also improved fruit quality and flavour. Chemical analysis indicated that it increased the fruit solids by 1.2%, soluble sugar by 1.1% and vitamin C by 1.1 mg/100g, and decreased organic acids by 0.01% (Table 8).

Table 8 Fruit quality as affected by different treatments