DRIP IRRIGATION: A PROMISING METHOD OF IRRIGATION TO SUSTAIN SUGARCANE PRODUCTIVITY IN REDUCED WATER SUPPLY SITUATION ATTRIBUTABLE TO CLIMATE CHANGE

摘要

Sugarcane is a high biomass crop which requires large amounts of water. Irrigation is necessary in order to produce sugarcane in almost all parts of the country, but water supplies are becoming increasingly limited. Furrow irrigation, the water application method most often used, can be efficiently operated, but is usually poorly managed resulting in not more than 30%-40%, of the water applied actually being used by the crop. The amount applied is determined by the amount necessary to push the water across the field and to cause thorough wetting. Drip irrigation allows for much more uniform, distribution as well as more precise control of the amount of water applied. Smaller amounts of water can be applied at more frequent intervals in order to maintain optimum soil water conditions resulting in maximum plant growth. Drip irrigation systems offer more precise water control than conventional furrow irrigation, but are more expensive. Drip irrigation can be a more efficient means of applying water and other crop nutrients, particularly nitrogen (N), so that water and nutrient application rates can be reduced in fertigated crops. With receding water availability, irrigating sugarcane will be increasingly difficult using traditional irrigation methods. Drip irrigation would, allow increasing irrigated area, with the. existing or even reduced irrigation water. The drip irrigation adoption in sugarcane increases water use efficiency (60-200%), saves water (20-60%), reduces fertilizer requirement (20-33%) through fertigation, produces better quality crop and increases yield (25-40%) as compared with conventional irrigation. While modern irrigation technology is capable of precise control of water application, there is a lack of information on how to use it. Data is needed on which to base the decision about how often and how much water should be applied to sugarcane. In the present paper, results of experiments on drip irrigation and fertigation obtained in different parts of the country are discussed.