Efecto del exceso de humedad del suelo sobre el rendimiento en algunos cultivos de importancia agrícola en Cuba.

Rainfall excess during the rainy season is the main cause of soil waterlogging in Cuba. In areas with poor soil drainage, surface drainage is the best solution for cropping during the rainy season, but for an adequate drainage system design, it is necessary to know the required time to evacuate the excess rainfall before the crop is affected by waterlogging in soils. Data from different experiments carry out in Cuba, were if was measured the effects of the numbers of days with excessive soil moisture on yield in different crops; where adjusted to a piecewise linear model similar to one developed for Gupta et al (1992) in India. Adjusting the model, it was find that there is not yield declined for a few initial days of submergence, beyond this period, if submergence continue, there would be linear decline in yield. The unknown parameters in the model are optimum yield, threshold time and the slope which represent the percent yield reduction per day of additional submergence beyond the threshold. The model worked well in the crops selected (sugar cane, black bean, soya bean, potatoes, star grass and king grass); in some of them like black bean and potatoes, the threshold value was cero or very closed; the highest percent values of yields reduction in relation with the number of submergence days were 34,3, 23,2 and 16,3 for potatoes, black bean and soya bean respectively and lowest were star grass, sugar cane and king grass. The prosed model permit to calculate the drainage requirements and the economic evaluation of crop submergence and the economic value of the investment to do in drainage; it is recommended to continues the research and to extend the model to others important crops in the country like corn, sorghum, sunflowers and others that are planted in soils susceptible to submergence. [ABSTRACT FROM AUTHOR]