374 



THE IEEIQATION AGE. 



IRRIGATION EXPERIMENTS IN ARIZONA. 



Investigations Covering a Period of Four Years at the Experi- 

 ment Station Farm at Tucson. 



BY PROF. ALFRED J. M'CLATCHIE, 



Agriculturist and Horticulturist of the Arizona Agricultural Experiment 

 Station. 



(Continued.) 



The method of providing for the irrigation of 

 sugar or garden beets depends upon the time of the 

 year they are sown. If planted during the cool part 

 of the year November 15 to the first of March they 

 may be sown just as they are in regions where they 

 are not irrigated, and furrows subsequently made for 

 their irrigation. But if they are planted at other times 

 of the year it is necessary to sow the seed along pre- 

 viously .made furrows, or to make furrows as the sow- 

 ing is done, since a good stand can not be secured dur- 

 ing dry weather without irrigation. If the seeding is 

 done during the cool part of the year the crop will 

 need no irrigation for a month or two. If the seed 

 be sown during the warm weather of early fall the 

 crop will need frequent irrigation until cool weather 

 arrives. If sown during the warm weather of spring 

 irrigation will be necessary during the entire period 

 of growth. It is not usually advisable to sow either 

 sugar or garden beets so late in spring that they must 

 be grown entirely by irrigation. 



Beets do best sown during September, October, 

 January and February. At whatever times during 

 these months the seeding is done, the crop makes the 

 most of its growth during the cool part of the year, 

 and is grown with a comparatively small amount of 

 water. During ordinary years the greater yield will 

 be obtained with the same amount of water the earlier 

 they are sown after the coldest weather is past. The 

 coldest weather of the winter 1899-1900 occurred be- 

 fore Christmas, and the beet sown December 26 por- 

 duced better results than those sown later and given 

 the same amount of water. The year previous those 

 sown during January produced a larger yield than those 

 sown during either December or February and given 

 the same amount of water. The same year a yield of 

 nearly ten tons per acre was secured by the use of 

 about one foot of water previous to sowing the seed 

 and of about .5 of a foot applied about two and one- 

 half months afterward 1.5 feet in all. This was in 

 a fine adobe soil, quite retentive of moisture. To pro- 

 duce the same crop in a gravelly, porous soil required 

 the use of nearly three feet of water. 



CABBAGES. 



After the plants have been raised in beds in the 

 usual way they are set along furrows that have been 

 recently wet or through which water is run immediately 

 after setting. In either case the individual plants are 

 usually watered by hand as they are set. Plants are 

 set out from September to November inclusive, and 

 during January and February, from seed sown a 

 month or two previous. The furrows along which they 

 are set are usually permitted to remain until the plants 

 are well established. They are then cultivated up and 

 made afresh for each subsequent cultivation. During 

 the early stages of growth they are run near the plants, 

 but later are run midway between the rows. Reference 



to Table V will show that cabbages require a large 

 number of irrigations. 



While this crop is grown mainly during the cool 

 part of the year, when evaporation is comparatively 

 slow, yet the large part of the soil left unshaded by the 

 crop, there being thus little check to evaporation there- 

 from, and the shallow rooting of the plants, thus re- 

 quiring frequent irrigation, cause the need of a com- 

 paratively large amount of water to produce a crop. 

 Also, in order to thrive they need to have the soil kept 

 moister than do many other crops. It will be seen that 

 a total of five feet was applied during the sixteen irri- 

 gations. 



CORN. 



Corn is planted in soil that has been previously 

 irrigated, in some cases with a combined lister and 

 drill, but more usually along small furrows through 

 which water has been previously run and that are left 

 for the first irrigation. Some farmers, however, drop 

 the seed into each third or fourth furrow as the land 

 is plowed. When the corn has come up and the water 

 applied previous to plowing and planting has evapo- 

 rated, furrows are run between the rows for subsequent 

 irrigation. 



For table use, corn is planted during February, 

 March, July and August. Field corn is planted dur- 

 ing July only in this region. When planted at this 

 time four to six irrigations of about 0.4 of a foot 

 each are necessary to produce a crop. It will be noted 

 by reference to Table VI that all the water the corn 

 grown during 1901 received was applied during the 

 first two months after planting, no irrigation, being 

 needed while it is maturing its ears. It will also be 

 noted that the total amount applied was just about 

 the same as that necessary to grow a crop of wheat. 



COWPEAS. 



Cowpeas may be planted in hills along furrows 

 that have been previously moistened, and through 

 which they are irrigated the first time; they may be 

 sown in drills and irrigated through subsequently made 

 furrows; or they may be sown broadcast, disked in and 

 irrigated by flooding. Whatever the method of plant- 

 ing and irrigation, they require quite frequent irriga- 

 tion. 



The amount of water necessary to grow a crop of 

 cowpea hay is so great, as compared with the amount 

 necessary to produce the same amount of alfalfa hay, 

 a nitrogenous forage of equal value, that its production 

 can scarcely be profitable in any part of the Territory 

 where the amount of water used is an object. The 

 need of this great amount of water is due to the fact 

 that the plant must pass through all of its stages from 

 germination to maturity during the warm part of the 

 year, when the loss of water from the luxuriant foliage 

 and from the soil is rapid. The same amount of foliage 

 produced during the cool part of the year would not 

 require much over half the amount of water needed 

 during the summer. However, where the water supply 

 is ample cowpeas may be grown to advantage between 

 two crops of grain. 



GRAIN. 



There are two methods of putting in grain in 

 southern Arizona. Either the fields are plowed quite 

 dry and, after being harrowed, seeded in this condi- 

 tion; or the fields are thoroughly irrigated before plow- 

 ing and the seed sown in moist soil. If the former 



