“The general conclusion may be that the protein content of alfalfa hay will decrease to some extent, according as the supply of water furnished the crop is increased; that is, by supplying the right quantity of water, a better quality of hay may be grown by irrigation than is often grown in humid climates in soil which receives only the natural rainfall. From what I know of the Colorado and Utah stations, I would judge that the quantity of water supplied at the Utah station was much larger than that supplied at the Colorado station. At the Colorado station the supply of irrigation water is often limited, and hence, the larger percentage of protein and fat which appears in the samples of hay grown and analyzed at that station.”
The annual report of the secretary of agriculture (1904) says that at the Utah station a series of co-operative experiments is in progress to determine the water necessary, and the most favorable method of application, to insure a maximum yield of alfalfa, and also experiments to determine the minimum application of water required to secure a crop. “It has been found that abundant irrigation throughout the season, 61 inches of water being applied, gave a yield of 6.2 tons per acre, while four irrigations in the early part of the season with only 25 inches gave five tons per acre, showing that beyond a certain supply the excess is wasted.”
A. S. Hitchcock, in United States Farmers’ Bulletin No. 215, speaking of the Utah experiment just mentioned, says that where the supply of water is limited a much less quantity than is ordinarily used will produce paying crops. The minimum quantity to produce a crop of alfalfa, and the time at which the water should be applied, depends upon the soil and climatic conditions. Below are results of experiments in 1903, by the Utah station:
WATER REQUIRED BY ALFALFA; QUANTITY AND DATE OF APPLICATION
| Date of each irrigation and quantity of water applied | Total Water applied | |||||||
|---|---|---|---|---|---|---|---|---|
| First | Second | Third | Fourth | |||||
| Acre in. | Acre in. | Acre in. | Acre in. | Acre in. | ||||
| June 16 | 3.360 | July 29 | 3.359 | .... | .... | .... | .... | 6.719 |
| June 29 | 5.970 | July 29 | 3.359 | Aug. 19 | 3.359 | .... | .... | 12.688 |
| June 16 | 5.070 | July 8 | 5.036 | Aug. 6 | 5.003 | .... | .... | 15.109 |
| June 29 | 7.020 | July 8 | 5.036 | Aug. 19 | 5.002 | .... | .... | 17.058 |
| June 15 | 5.030 | July 3 | 5.100 | Aug. 1 | 5.036 | Aug. 24 | 5.002 | 20.168 |
| June 20 | 6.774 | July 8 | 6.694 | Aug. 19 | 6.682 | .... | .... | 20.150 |
| July 8 | 12.490 | Aug. 9 | 12.506 | .... | .... | .... | .... | 25.002 |
| June 20 | 8.303 | July 6 | 8.352 | Aug. 19 | 8.362 | .... | .... | 25.017 |
| June 15 | 6.320 | July 6 | 6.248 | Aug. 1 | 6.248 | Aug. 29 | 6.250 | 25.066 |
| June 16 | 6.250 | June 23 | 4.280 | June 30 | 5.705 | July 7 | [4]5.230 | 61.465 |
| June 23 | 6.250 | July 7 | 6.220 | Aug. 15 | 6.250 | Aug. 31 | 6.250 | 24.970 |
| June 16 | 6.250 | July 7 | 6.220 | Aug. 6 | 6.750 | Aug. 31 | 6.250 | 25.470 |
| June 23 | 6.610 | July 7 | 3.720 | Aug. 15 | 3.250 | Aug. 31 | 3.750 | 17.330 |
| June 16 | 3.980 | July 7 | 3.720 | Aug. 6 | 3.750 | Aug. 31 | 3.750 | 15.200 |
[4] This plat was given 5 inches of water on each of the following dates: July 14, July 22, July 28, August 4, August 17, August 25, August 31, September 8.
DATE OF HARVEST AND YIELD OF HAY
| Date of harvest and yield of hay at each cutting | Total yield of plat | Calculated yield per acre | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| First | Second | Third | |||||||||
| Pounds | Pounds | Pounds | Pounds | Tons | |||||||
| June 26 | 264 | Aug. 12 | 50 | 1⁄2 | .... | .... | 314 | 1⁄2 | 3.145 | ||
| June 26 | 177 | Aug. 12 | 101 | .... | .... | 278 | 2.780 | ||||
| June 26 | 261 | Aug. 12 | 68 | 1⁄2 | .... | .... | 329 | 1⁄2 | 3.205 | ||
| June 26 | 204 | Aug. 12 | 108 | 1⁄2 | .... | .... | 312 | 1⁄2 | 3.125 | ||
| June 26 | 191 | Aug. 12 | 85 | 1⁄2 | .... | .... | 276 | 1⁄2 | 2.765 | ||
| June 26 | 175 | Aug. 12 | 74 | .... | .... | 249 | 2.490 | ||||
| June 26 | 93 | Aug. 12 | 62 | .... | .... | 155 | 1.550 | ||||
| June 26 | 99 | Aug. 12 | 44 | .... | .... | 143 | 1.430 | ||||
| June 26 | 224 | Aug. 12 | 140 | .... | .... | 364 | 3.640 | ||||
| June 18 | 176 | 1⁄2 | Aug. 10 | 177 | 1⁄4 | Oct. 16 | 120 | 1⁄2 | 474 | 1⁄4 | 6.243 |
| June 18 | 170 | 1⁄2 | Aug. 10 | 136 | 1⁄2 | Oct. 16 | 73 | 3⁄4 | 380 | 3⁄4 | 5.017 |
| June 18 | 147 | Aug. 10 | 141 | Oct. 16 | 61 | 349 | 4.598 | ||||
| June 18 | 105 | Aug. 10 | 112 | 1⁄4 | Oct. 16 | 46 | 263 | 1⁄4 | 3.468 | ||
| June 18 | 112 | 1⁄2 | Aug. 10 | 106 | Oct. 16 | 35 | 253 | 1⁄2 | 3.340 | ||
“It will be observed that the maximum crop was produced by applying plenty of water throughout the growing season. However, it is also to be noted that a much less quantity of water, when applied at intervals of three or four weeks, produced a fair crop. Fifteen and 17 inches of water applied in this way produced more than half as much as 61 inches applied at frequent intervals. Furthermore, three irrigations of 15 to 17 inches produced about the same results as the same amount applied at four irrigations. In applying irrigation water to fields it is necessary to saturate the soil to a reasonable depth. All the water that drains off beyond the amount required for use is lost to the crop. It is not necessary to apply water again until the crop has removed a large part of the available supply.”
