FRUIT YIELD RESPONSE OF ‘MARSH SEEDLESS’ GRAPEFRUIT TO SUPPLEMENTARY IRRIGATION

The effects of supplementary irrigation regimes on the yield of grapefruit (Citrus paradisi) were assessed in Malawi between 1976 and 1979 using the ‘Marsh Seedless’ cultivar.
The irrigation treatment effects were not statistically significant.
There was, however, an apparent increase in yield, number of fruits per hectare and fruit size due to treatment effects.

Irrigation applied from the flowering stage through fruit maturity was more effective than irrigating frequently throughout the year.
An evapotranspiration (Et) factor calculated as 0.5 of the water evaporation from a Class A pan (Eo) was a better estimate of the irrigation interval as compared to an Et factor of 0.3 of Eo.
A water deficit of 5 cm from field capacity was the optimum level at which the depleted available soil moisture could be replenished effectively.
It was too early and too late to irrigate when the soil deficits reached 2.5 cm and 7.5 cm respectively.

X African Symposium on Horticultural Crops

E.H.C. Chilembwe

https://doi.org/10.17660/ActaHortic.1985.158.21