Furrow irrigation is a surface irrigation system also called gravity irrigation in which the water is placed at the head of the furrows and by gravity advances to the lowest end allowing; During this time, the infiltration of a sheet of water of greater value generally occurs at the head of the field.
With this method the water is applied only during the advance phase, cutting off the supply a little before the advancing front reaches the end of the groove.
The adequacy of the land, the leveling of maintenance, the aporque of the plants, the programming by water balance, the measurement of the water and the applications controlled are necessary conditions to improve the efficiency of the work and diminish the costs.
Continuous groove irrigation
Continuous furrow irrigation is the method of highest water consumption in the cultivation of sugarcane; Its efficiency is low due to water losses in irrigation ditches and furrows, mainly as a result of the infiltration of water in the soil.
In this modality of irrigation the water is placed in all the furrows, generally applying flows between 3 and 6 l / s. Continuous groove irrigation can be used for cane germination when sprinkler irrigation equipment is not available.
In soils of coarse texture or very compacted, where you can not apply irrigation by alternate groove or other method such as sprinkler or drip, continuous groove irrigation is used.
Alternate groove irrigation
Alternate groove irrigation consists of placing the groove water in between; This system allows the volumes of water applied to the field to be reduced between 25 and 50% with respect to the applications by continuous furrow, increasing the yield of the irrigator from 1.3 to 2.3 ha / man / day.
The work of aporque is an indispensable requirement for the application of the irrigation by alternate groove because it forms a guide that avoids the passage of the water to the continuous groove. The aporque should be made with a height of 10 to 20 cm forming a small rounded mound in the cane rows.
In clay soils that are cracked it is recommended to use flow rates through a groove of 4 to 6 l / s. Alternate groove irrigation can be applied without the need to make changes in insoles or in socas with chopped or stranded waste.
During the initial period of development of the template cane, the furrows are very disturbed due to intensive soil preparation practices carried out for planting. After the first irrigation, a natural compaction process occurs that reduces the infiltration rate and makes possible the use of alternate groove irrigation.
The management of flows to irrigate through alternate groove is similar to that used in continuous groove irrigation; however, it has been observed that the water advance time can increase up to 30% when the same flow rate used for continuous groove is applied. It is recommended to increase the flow through alternate groove between 1 and 2 l / s to reduce the water advance time.
Pulse irrigation is defined as the intermittent application of water to the grooves. In this method, the water is applied intermittently to the grooves by using poly-tubular or pipes with gates and a butterfly valve operated by a computer equipped with a solar panel.
Pulse irrigation has been evaluated by Cenicaña in cooperation with mills and growers, showing promising results in terms of application efficiency.
In commercial fields of Ingenio Manuelita, pulse irrigation used 28% less water volume than that used for continuous flow. When watering with continuous flow the volume of water exceeded 1200 m3/ ha, while watering with intermittent flow (pulses) the additional water savings reached 400 m3/he has. The comparison was made in the first semester of 2003 in fields of sociated reeds, with length of grooves between 130-150m, applying irrigation by alternate furrow and with flows between 4 and 6 l / s.