492 SUCCESSFUL FARMING 



is believed to be preferable to plowing both ways across the grove, as is 

 sometimes done. After this thorough disking the land is harrowed again 

 and then left until it is necessary to furrow out for the first irrigation. In 

 harrowing, either a knife harrow should be used, or if a spike-toothed har- 

 row is used the teeth should be sloped backward in order not to pull up the 

 cover crop. 



The first irrigation is delayed if possible until after the blooming period, 

 but the trees must not be allowed to suffer for water. After the irrigation, 

 as soon as the soil has dried sufficiently, the land is harrowed and disked 

 both ways and again harrowed. This should leave the surface soil thor- 

 oughly pulverized, and with a dry dust mulch. No other cultivation is 

 necessary until after the second irrigation. 



During the dry summer period an irrigation is necessary about every 

 month. Following each of these irrigations, the land should be harrowed 

 as soon as dry enough and about a week later cultivated both ways with 

 some narrow, shoveled cultivator, running to a depth of 4 to 6 inches. 

 These alternating periods of irrigation followed by cultivation are continued 

 during the summer until the winter cover crop is sown in the fall. 



In both Florida and California, the practice of mulching a portion or 

 all of the land in the grove is gaining in favor. 



Irrigation. — In the citrus regions of California and Arizona, irrigation 

 is necessary and is one of the most expensive and difficult of all the various 

 grove operations. Water in these sections is, however, the limiting factor 

 of production, and an ample supply must be provided. Water is taken 

 directly from flowing streams, is pumped from underground basins, or is 

 taken from large, artificial storage reservoirs, filled mainly during the winter 

 rains. Different locations and soils require different amounts of water. 

 A porous, gravelly soil requires more water than a heavy clay or adobe soil, 

 the latter being more retentive of moisture although more difficult to wet. 

 Groves near the coast where there is more moisture in the air require less 

 water than those in the drier interior regions. In general, enough water 

 must be provided to be equal, when combined with the natural rainfall, 

 to a depth of 35 to 45 inches. In a single irrigation it is ordinarily expected 

 to apply enough water to cover the entire surface irrigated to a depth of 

 about three inches. The supply of water usually provided for citrus 

 orchards is one miner's inch to every four to eight acres.* 



In the furrow method of irrigation the water is distributed over the 

 grove by means of several furrows, usually four to six, between each row of 

 trees. These furrows, which are made by a special furrowing tool or plow, 

 should have a uniform fall, preferably not exceeding a grade of one-half of 

 one to three per cent. The water should run through them slowly to give 

 the best results. While these furrows are usually run straight, not infre- 

 quently they are curved in between the trees to water the middles. The 



* The miner's inch most commonly used in California is the amount of water that will flow through 

 a 1-inch square opening under a 4-inch pressure head. This equals 9 gallons per minute. The statute 

 inch is 11 j gallons per minute. 



