Service Contract No 2007 / 147-446 Strategic ... - Swaziland

Table 8: Industry area (ha) by irrigation system type (2009)Irrigation Ubombo Simunye Mhlume TotalCentre Pivot 4747.76 2551.86 702.57 8002.19Flood 524.40 4.16 528.56Floppy 96.80 196.25 293.05Furrow 1-5 1252.10 1252.10Furrow 11-15 465.50 465.50Furrow 6-10 2383.80 12.69 2396.49None 27283.90 1039.92 87.60 28411.42Overhead 484.71 15.00 499.71Semi Solid-Set Spl 466.40 143.80 977.60 1587.80Sprinkler (17 mm) 15.00 232.09 247.09Sprinkler (24 mm) 3845.20 1856.86 5702.06Sprinkler 1-5 670.70 670.70Sprinkler 6-10 7377.00 7377.00SUB-SURFACE DRIP 88.74 41.70 303.80 434.24Sub-surface drip (1.5 m) 45.40 59.80 22.30 127.50Surface drip (24 mm) 42.10 591.60 633.70Furrow 1451.30 7394.13 8845.43Sprinkler (42 mm) 362.40 1076.50 1438.90Sub-surface drip (1.8 m) 8611.40 1256.60 9868.00Sprinkler 11-15 3883.11 3883.11Total 49789.51 16970.42 15904.62 82664.555.2.1.8 The Efficient Use of Irrigation WaterIrrigation water efficiency depends upon the type of crop grown, the degree of cultivation, theefficiency of the irrigation system and the accuracy of measurement of crop water needs.Species vary significantly in their water requirements 10 , whilst water consumption can bereduced by using short season varieties. The amount of water pumped is determined by thefarmers’ measure of the rate of evapotranspiration – the more accurate the measurement theless water applied.Swaziland’s sugar industry is making some effort towards conserving water. This partlyreflects an acceptance by the major cane producers that, by having free access to such ascarce and valuable resource, they are in a privileged position and consequently should usethe resource responsibly. In the case of RSSC, which has switched a major area of its caneto water-efficient drip irrigation on its Simunye estate, its action is also a response to the factthat it relies upon, and is the major user, of the finite supply of water in the Mnjoli Dam.Consequently it must restrict usage per hectare in order to be in a position to expandplantings. In the other cane areas, water is shared between a larger number of growers ofcane and also growers of other crops. There is consequently less incentive for individualcane growers to save water.10 For example sweet sorghum and tropical sugar beet have significantly lower water requirements than sugar cane.RDMU (Strategic Environmental Assessment of the National Adaptation Strategy) - Page 43