Technical advances for irrigation programming and management in sugar cane

The Cauca River Valley is a region that can be considered semi-humid, with fine-textured soils, where sugar cane is planted and harvested throughout the year. Irrigation has been adopted as a routine practice, and thus 95% of the cultivated area receives supplementary irrigation.

Precipitation in normal years ranges from 800 to 2600 mm, depending on the location in the Valley, and there are two rainy periods during the year, spanning the months of March to May and September to November.

The topography is generally flat, with slopes of less than 1.5%. In recent years, the area cultivated with sugar cane has increased from 135.000 ha in 1984 to 185.000 in 1996. This has displaced sugar cane cultivation to the foothills of the mountain ranges and to other regions with slopes that limit the use of furrow irrigation.

The availability of water for irrigation has decreased significantly in recent years due to changes in the quantity and frequency of rainfall, as well as increased demands for water for municipal and industrial use. In this region, it is normal to find areas with superficial water tables and good quality water that can provide up to 40-50% of the sugarcane's water requirements. Therefore, it is necessary to take into account the contribution of groundwater in the programming.
of irrigation by water balance.

The objective of this publication is to promote the efficient use of irrigation water and the adoption of water balance at a commercial level, choosing to present several alternatives for its implementation, which differ in their degree of adaptation to the conditions of the different sugar mills and sugar cane growers. In our environment, the level of acceptance of water balance as an irrigation programming tool is incipient; for this reason CENICAÑA has been investigating different alternatives that allow its adoption at a commercial scale.

Water balance has been considered a technology that allows saving water. However, it is necessary to clarify that it is only a method that brings us closer to rational water management and, as such, in dry years it may indicate that we should water more and in wet years that we should water less. Of course, when the custom is to apply an excessive number of irrigations, water balance will result in an immediate saving of water.

The information presented in this document is, for the most part, the result of cooperative research conducted by CENICAÑA, sugar mills and growers and does not necessarily represent the current state of water management in commercial sugarcane plantations.