High Potassium Required for Good Fruit Yield

Fruit crops are generally heavy feeders of plant nutrients, particularly potassium (K). High and balanced K nutrition of fruit crops ensures better yield and quality of marketable products. The influence of K on fruit quality is greater than any other plant nutrient. Although K application is recommended for all fruit crops in India, normally application rates are far below the crop's requirement. Table 1 provides a general idea on nutrient removal by some fruit crops and emphasizes the importance of K in fruit production:





Table 1. Nutrient removed in fruit harvest (kg/ha)

Fruit crop	Fruit yield (tonnes/ha)	N	P2O5	K2O
Mango	15.0	100	25	110
Banana	57.5	322	73	1180
Citrus	20.0	22	12	57
Pineapple	84.0	150	45	530
Papaya	80.0	225	60	180
Grape	20.0	160	40	180
Litchi	10.0	220	35	290

Based on experiments and considering profitability, the following fertilizer schedule is recommended for fruit crops in West Bengal. In most fruit crops, a 1:1 ratio of N and K₂O (mango, pineapple, litchi and guava) or a higher K₂O ratio (papaya and banana) was found necessary for a good harvest (Table 2).

Table 2. Fertilizer recommendations for West Bengal.

Fruit crop	Rate	N	P2O5	K2O	Source
Mango (fazli)	g/tree/year	1000	500	1000	Mallik et al. (1985) Abst. Int. Mango Symp., Bangalore pp. 30-37.
Citrus (Darjeeling Mandarin)	g/tree/year	600	200	400	Mitra & Ghosh (1991) Scientific Hort., 2 : 15-20.
Pineapple (Kew)	kg/ha	600	400	600	Mitra & Sheet (1995) Pineapple News, USA. p2
Litchi (Bombai)	g/tree/year	600	200	600	Dwivedi (1996) Ph.D. Thesis B.C.K.V, Mohanpur, West Bengal.
Papaya (Ranchi)	g/tree/year	250	200	600	Ghanta et al. (1995) Ann. Agric. Re., 16 : 405-408.
Guava (L-49)	g/tree/year	260	130	260	Mitra (1987) J. Potassium Res., 3: 160-163.
Banana (Giant Governor)	g/tree/year	250	125	500	Hassan et al. (1999) Environment & Ecology, 17 : 543-545.

These are usually applied in split applications throughout the growing cycle. In case of mango and citrus, the yearly doses are supplied in two splits, at the beginning and end of the monsoon each year. For banana, fertilization is done on 3, 6 and 9 months after planting. While for pineapple, the total amount is supplied in four splits, at 3, 6, 9 and 11 months after planting. Papaya requires fertilization at intervals of two months and litchi should be fertilized just after flowering and after harvest each year (Mitra, 2001, personal communication).