EVAPOTRANSPIRATION AND CROP COEFFICIENTS IN BANANA

In order to establish guidelines for crop water management using various climatic parameters, banana evapotranspiration was measured at the Government Research Station on the island of Tenerife (Canary Islands), with a field lysimeter set up as follows: two 60 m³ tanks, with ten plants per tank, at 2x2 m. planting distance; drip irrigation was applied daily, using two ET/E₀ ratios of 1.1 and 1.4, E₀ being the evaporation of a class A tank.

The volumetric balance of the lysimeter is expressed in the equation ET=P+I+D+ΔW, where ET is the crop evapotranspiration, P is the precipitation, I is the irrigation, D is drainage water, and ΔW are the changes in content of the soil water as measured by neutron probe.

Using data recorded between 1988 and 1990, a fifth-degree polynomial regression was adjusted for averages of 10 and 30 days, obtaining ET values ranging from 2.10 to 4.56; low temperatures during January and February had a negative effect.

Three crop coefficient curves were calculated by ET/E₀ ratios versus shaded area, where ETo was E₀, Penman-Monteith, and E₀xKp.