The effect of different levels and timing of nitrogen fertilization on the yield and internal quality of mangoes (cv. Tommy Atkins).
Smith B. L.
Author Affiliation: ARC-Institute for Tropical and Subtropical Crops, Private Bag X11208, Nelspruit 1200, South Africa.
Neltropika Bulletin : 23-27, 31
Abstract : Increased levels of N fertilization resulted in a very small increase in foliar N concentration for the three seasons (1994/95, 1995/96 and 1996/97), the T4 timing of application (one-quarter in each of February, April, August and October) giving the highest yield. This indicates the necessity of ensuring N availability throughout the growing season. Combining the records over the three seasons, the N3 (900 g/tree per annum) and N4 (1350 g) levels would appear to correspond to the highest yields. Too high levels of N application tended to lead to reduced yields and also delayed colour development. A highly significant relationship between foliar N concentration and yield for the T2 timing of application (half at full flowering and half in November) was obtained, with the optimum being in the range 1.18-1.43% N. This value is somewhat lower than for the first two seasons. A polynomial regression of the N:K ratio versus yield for the T3 timing of application (half in January/February and half at the start of flowering) gave an optimum N:K ratio in the range 1.9-2.2 and demonstrates the importance of the specific N and K levels in mango nutrition. This would need to be studied further with regard to fruit size and possibly the effect on soft-nose/jelly-seed.