TWO METHODS OF FARM IRRIGATION. 



By Charles Di.mo.nd Horatio Bkaine, A.MT.C.E, 



The proper handling of water in the held when irrigating— or 

 leading, as it is often called in South Africa— is a subject that 

 ■ deserves far more attention from farmers and irrigation engineers 

 than it has received in the past. I would impress upon you that 

 the more carefully, and the more scientifically, you use water when 

 irrigating, the better results vou will obtain and, consequently 

 the more monev you will make. The subject is one that should 

 receive the earnest attention of every irrigator in South Atrica, 

 .and I propose to direct attention to two methods— flood irriga- 

 tion and furrow irrigation. 



FLOOD IKKIGATION. 



Many beginners start irrigating by trying to spread a sheet of 

 water over their land. Thev think the ground looks level and 

 .even enough, and turn on the water ; but, instead of spreading out 

 the water runs off to one side, collects in little pools, and runs all 

 over the place, leaving strips of high ground quite dry. Ihe 

 water shows that the ground is not half as level as they thought^ 

 Some of them let the water go on running, hoping that the h,^.h 

 places will graduallv get wet by soakage from the sides. This is 

 a horrible waste of water; it leaves part of the soil too wet and 

 .part not wet enough. Probably most beginners, when they see 

 Ihis happening, put on boys to level off the rough ground and 

 throw the loose earth into the deepest places. When the water is 

 turned off, thev find that, although the high places are lower, the 

 surface is more lumpv than ever, and the low places are filled with 

 a laver of paste that' will bake in the hot sun. The layer may be 

 thick enough to stop manv kinds of seeds, and sicken most of the 

 .plants that manage to pu^h thr.^ugh it. A man who has heard of 

 the "basin" or "check" system of irrigation mav divide his 

 land into plots, and surround them with banks of earth high 

 <?nough to raise the water over all the high places Now this 

 basin svslem when properlv used is quite indispensable in manv 

 cases, and is very extensivelv employed in all parts of the world. 

 In Egvpt some of the basins vary from 5,000 to 45,000 acres in 

 <xtent But our beginner is certain to find trouble with it, it the 

 ground enclosed by the banks is rough and uneven ; because as 

 'the water subsides he will still find pools of standing water. Manv 

 plants cannot stand that, and the crop will be patchv instead of 

 being uniform, and there will probablv be several bare places. On 

 manv soils, and for manv plants, it is absolutely necessary to pro- 

 vide' for a quick clearance of the water after the ground is wet 

 enough. 



One man mav be surprised to find that the crops on the highest 

 places are doing best, and that where the water was deepest thev 

 .have not even sprouted. The deeper the water the worse will be 



