82 THE RAISIN INDUSTRY. 



soils are frequently improved by irrigation, and in course of time lose 

 their impervious nature and become subirrigated. If the land is toler- 

 ably level by nature, and there are prospects of subirrigation soon 

 appearing, it may be unnecessary to level the land, and flooding with 

 temporary checks may be used with advantage for the first few seasons. 

 Furrowing will generally assist this mode of irrigation. 



Irrigation by Furrowing. This method of irrigation is practiced 

 where the land is not sufficiently level to be flooded, or when the water is 

 not sufficient to enable the irrigator in a short time to flood the land. 

 The practice of furrowing simply consists in plowing furrows alongside 

 of the vines, and then to lead the water in the furrows. This system 

 is by far the one that is most practiced in Southern California, as it has 

 some advantages over the flooding; it is, however, not so effective and 

 cannot supply the vineyard with as much water as flooding. To use 

 the furrowing system to advantage, the land must have been previously 

 leveled, but not necessarily graded to an absolute level. It is enough 

 to have the surface smooth and on an even grade, in order that the 

 water may run from a higher point to a lower one without spreading 

 or breaking out. Especially all knolls in the vineyard must be 

 leveled off, and care must be taken to fill all hollows or sinks in which 

 the water would otherwise collect. 



After the vines are planted, or when irrigation is necessary, one or 

 more furrows are plowed on each side of the vine, and the water is 

 allowed to run in them for several hours, or even days, until the soil 

 is sufficiently soaked. In many places three furrows are made between 

 the rows of vines, and the water is allowed to run in at one end and 

 out through the other in a stream only sufficiently large to cause all the 

 water to sink. Where particular nicety is required, the waste water 

 which runs out at the farther end may be collected in a trough with per- 

 forated holes, through which it is conducted to a ditch or lower check. 

 Similarly, a long trough may be used for conducting the water to the 

 land in the first instance, and allow it to run out through a number of 

 small holes, one of which is situated in front of every furrow. When 

 the ground is well prepared, level and with an even slope, this system 

 of irrigation is very perfect, and causes but little expense and trouble 

 in management. In Riverside the vines are irrigated thus every three 

 or five weeks, while in Redlands less irrigation is used on old vines. 

 As a rule, in Southern California the furrowing system is the accepted 

 one as being best adapted to the nature of the country. The water is 

 conducted both in open ditches and in pipes, and when under pres- 

 sure saves much labor and expense which would otherwise be required 

 for the continued construction and repair of ditches. 



The furrowing system has, however, its Disadvantages. It requires 

 a longer time to fill the soil sufficiently, and accordingly it takes many 

 more irrigations to accomplish as much as with flooding. As advan- 

 tages of this system, we might state that it requires no banks or 

 levees to back up the water, and a vineyard irrigated this way can be 

 kept entirely free from weeds by a few cultivations, while a checked 

 vineyard must besides be cleared with hand labor, as the banks and 

 checks are apt to be destroyed by cultivation. 



