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00181)7 Timeliness of irrigation. Research at the Garden City Experi- ment Station with winter wheat has shown that withholding water at certain stages of growth (even to the point where wheat growth may be restricted) can conserve water and even increase yields over those with injundicious use of irrigation. This year's dryland wheat yields (and others like them in the past) illustrate this rather dramatically, During mid-May this year, I inspected a number of wheat fields showing signs of severe moisture shortage in our area. With hot, dry weather, those fields would have produced little or no gain. An inch- and-a half of rain on May 28 and two similar rains, June 8 and 17, together with cool ing weather, produced wheat yields equal to those from irrigated fields. (Some in excess of 50 bushels per acre.) Obviously we cannot control the temperature but we can do a more effective job of water appl ication. Similar (if less striking) data are available for other crops. With limited water available, we may become less concerned with unusually high yields. Adequate data exist to question the practicabil ity of pushing for maximum yields if those last few bushels come at exorbitant costs of scarce water. Our own work with winter irrigation in the production of sorghums illustrates one possible method of greater efficiency of irrigation facil ities. An application of ten to twelve inches of irrigation water during the winter months has produced a ten-year average yield of 67 bushels per acre on continuously cropped land. Although some irrigation farmers have a sort of sixth sense when judging their water appl ications, it seems reasonable to expect more efficient use of water with more adequate measurements. Engineers and others (including many farmers) know the value of cutback heads and of regulating appl ication rates to prevent tail-water loss. Tail water pits and reuse of the water are compromise measures with some practical value. Much of our irrigated land could be better prepared for more efficient irrigation. With cheap, plentiful water, there is less inducement to do this, As water becomes scarcer, improve- ments can be made. Such land improvement will make natural precipitation more effective, also. Operation of sprinkler systems can be improved. We have seen much runoff water (even in the sandhill region) where application rates are too high. On hardland, runoff is even a greater problem. Optimum ferti lizer applications may help increase irrigation water efficiency. Farmers could make more complete use of soil tests and realistic interpretations of such tests, 13.