China is one of the banana provenances dated back to >3000 years ago. Achieved rapid development in recent 20 years, banana has become the most popular fruit in southern subtropical areas. Due to its large growth and high yield, high rates of fertilizers, several-folds more than other crops, are usually required, which become the main cost of production. A number of workers have studied the optimal rates and ratio of nutrients for healthy growth and high yield of banana, but few have assessed different methods of fertilizer placement yet. The commonly used fertilizer placement in Guangdong includes broadcasting, hole application, banding and fertigation. The objective of the this study was to investigate the effect of these different fertilizer placement during different growing periods on banana yield, quality and profit in order to offer technology for best nutrient management for banana production.
The experiment was carried out in March, 2008 in Fanyu district, Guangzhou on an alluvial soil. The soil was acidic with pH 4.46, contained 22.6 23.2 g/kg of organic matter, 116.2, 122.8, 1047.7, 137.2, 92.4, 51.7, 3.9, 395.5 and 1.1 mg/L of available N, P, K, Ca, Mg, S, Mn, Zn, Fe, and B, respectively.
There were four treatments of different fertilizer placement: broadcasting every time (T1); broadcasting at early stage and banding or hole application at middle to late growth stage (T2); fertigation at early stage and broadcasting at middle to late growth stage (T3); fertigation at early stage and banding or hole application at middle to late growth stage (T4). Each treatment repeated three times. Fertilizer rates for N, P and K were 556.5 kg N/ha，178.5 kg P₂O₅/ha and 631.5 kg K₂O /ha.
Plant growth
The banana in the T1 and T2 grew taller and thicker stems and more uniform leaves than in the T3 and T4 most likely due to the T1 and T2 receiving higher rates of N and K at early growth stage (Table 1). At budding stage, however, the stem was the tallest in the T2, thickest in the T1 and the thinnest in the T4; T3 had the least number of green leaves. At floral emergence stage no significant difference in the above growth indicators was observed between treatments, a slight better growth in the T1 and T2 over the T3 and T4 resulted, which could be attributed to fertigation at early growth stage promoting stem growth more than broadcasting, but delaying plant floral emergence.

Table1 Plant growth affected by different placements.

Treatment	Growth stage			Budding stage			Floral emergence stage
	Stem height (cm)	Stem girth (cm)	Green leaves (No./plant)	Stem height (cm)	Stem girth (cm)	Green leaves (No./plant)	Stem height (cm)	Stem girth (cm)	Green leaves (No./plant)	Floral emergence rate (%)
T1	136.7a	35.8a	11.9a	217.2ab	54.6a	11.4ab	252.8a	62.9a	12.4a	36.7a
T2	137.7a	35.8a	11.4a	218.7a	53.5ab	11.7a	250.2a	61.0a	12.4a	40.0a
T3	136.5a	35.1a	11.8a	212.4b	54.1ab	10.8b	249.9a	62.1a	12.6a	26.7a
T4	132.6a	34.5a	11.4a	217.3ab	52.9b	11.0ab	251.1a	61.6a	12.7a	20.0a

Means following the same letter in a column are not significantly different (p<0.05)

Fruit growth
The T4 treatment achieved the highest fruit weight and fingers per hand (Table 2), while T1 and T2 had the highest single fruit weight. No distinct difference on finger length and finger girth was observed between treatments. It indicated that fertigation at early growth stage with banding or hole application at latter stages could increase weight and fingers per hand.

Table 2 Fruit growth

Treatment	Weight per hand (kg)	Fingers per hand	Weight per fruit (g)	Finger length （cm）	Finger girth(cm)
T1	3.61	18.3	197	26.7	13.4
T2	3.40	17.3	197	26.1	13.5
T3	3.30	17.7	188	26.7	13.1
T4	3.68	19.0	193	26.3	13.2

Fruit quality
Banana fruit in the T1 contained the lowest solids, 0.3%-1.0 % lower than other treatments. Content of vitamin C in the T4 was 0.55 mg higher than in the T3 and 0.22 mg higher than in the T1.Soluble sugar in the T4 was increased by 1.38%, 0.92% and 0.84% comparison to the T1, T3 and T2, respectively. Fertigation favored formation of thicker fruit peel which could prevent banana from insect and pest damage and result in better shelf life. Fruit quality, however, was hardly affected by methods of fertilizer placement.

Table 3 Fruit quality affected by different placements.

Treatment	Solid content (%)	Vc（mg/100g）	Soluble sugar (%)	Peel weight (% of total fruit weight)
T1	21.7a	9.08a	16.74a	29.4%a
T2	22.7a	9.52a	17.28a	28.4%a
T3	22.5a	8.75a	17.20a	31.5%a
T4	22.0a	9.30a	18.12a	29.6%a

Banana blight
Banana blight is a kind of soil-born disease that attacks vascular bundle and causes serious yield losses once infected. Due to unfavorable weather, too much rains resulting in high humidity in particular at the seedling stage, it may increase incidence of different diseases. It is surprising to see that there was no blight infection in the treatments of T1 and T3 and only slight infection in T2 at later stage, while severe infection was observed in the farmers’ treatment and T4(Table 4). This could be attributed to the imbalanced fertilization of he farmers’ practice that weakened the disease resistance of the plant, and to the banding damaging some plant roots that no doubt led to higher susceptibility to blight infection.

Table 4 Blight incidence for banana.

Treatment	Aug.,22	Aug.,29	Sept., 5
T1	0	0	0
T2	0	0	3.3
T3	0	0	0
T4	3.3	3.3	3.3
Farmer’s practice	3.0	3.0	16.6

Banana yield and profit
At last, different treatments produced the similar yields (Table 5). The treatment T4 produced slightly higher banana yield than the other three treatments. In the small-scale plantation, profit of banana was well corresponded to the yield level of different treatments. The best profit resulted from T4, i.e, fertigation at early stage and banding or hole application at middle to late growth stage, and followed by T1, that is, broadcasting throughout the growing season.

Table 5 Banana yield affected by different placements.

Treatment	Yield （kg/ha）	Yield increase
		kg/ha	%	kg/ha	%	kg/ha	%
T1	49848a	—	—
T2	48750a	-1098	-2.2	—	—
T3	48877a	-971	-1.9	127	0.3	—	—
穴T4	50715a	867	1.7	1965	3.9	1838	3.6

Treatment	Income ($/ha)	Input ($/ha)		Net profit ($/ha)	Increase
		Fertilizers	Others		$/ha	%	$/ha	%	$/ha	%
T1	14661	1376	5735	7549	—	—
T2	14338	1376	5735	7226	-323	-4.3	—	—
T3	14376	1376	5735	7264	-286	-3.8	37	0.5	—	—
T4	14916	1376	5735	7804	255	3.3	578	7.4	541	6.9

Treatment	Income ($/ha)	Input ($/ha)		Net profit ($/ha)	Profit increase
		Fertilizers	Others		$/ha	%	$ /ha	%	$ /ha	%
T1	14661	1376	39000	5735	—	—
T2	14338	1376	43200	6609	-941	-12.5	—	—
T3	14376	1376	40800	6999	-550	-7.3	390	5.6	—	—
T4	14916	1376	45300	6878	-671	-8.9	269	3.9	-121	-1.7