OCR Text |
Show K k SPLENDID BULLETIN JUST Hf ISSUED BY THE UTAH EX- V PERIMENT STATION. H Bulletin No. 104 on the storage H of winter precipitation in soils, has H just been issued by the Utah Ex- H poriment Station. As is indicated by I the title of the bulletin the subject I matter deals with the storage of win- H for precipitation, and contains data, part of which was cdllccted in tht H irrigation investigation!, and part of I which was obtained in the dry farm-H farm-H ing experiments. I The discovery that the natural pre- H cipation may be made a prime factor in the production of irrigated crops, I, really laid the foundation of farming Hi without irrigation. In fact, the cx- I periments in arid farming, begun at I the Station some eight years ago, I Y?crb inaugurated only after the Sta- I tion workers had become convinced l that the precipitation over the Great I Basin district was in most cases, I sufficient, if properly conserved, to produce, profitably, many of the sta pic crops without irrigation. Since that time the irrigation experiments concluded by the Station have shown that irrigation should be supplimcnt-al supplimcnt-al only to the natural precipitation; and that tthcrcforc, the irrigation farmer of the future must consider first the proper storage of the rainfall and snowfall 'in the soil, and later the water-right in the canal above his farm. The importance thus given to the natural precipitation, has naturally raised many new problems. Some doubts have been expressed concerning concern-ing the correctness of the statement that a large proportion of the winter win-ter precipitation 'is actually stored in the soil to be used by plants the following summer. Other questions have concerned themselves with the depth to which water may penetrate soils; its availability when held at considerable soil depths and the relationship re-lationship of water to plant food in the production of plants. Many of these questions have been investigated investigat-ed during the last eight years by the Utah Station, with numerous interesting in-teresting and some remarkable, results. re-sults. The bulletin under discussion concerns itself, only, with the study of the storage of the winter precipitation preci-pitation in the soil. By winter precipitation pre-cipitation is meant tht precipitation, whether in the form of rain or snow, ffoin harvest time to spring time. The bulletin was written by President Presi-dent J. A. Widtsoc, who is undoubtedly undoubt-edly the leading Western authority on this subject. The bulletin is Summaizcd briefly here: 1. The beginning of irrigation wisdom is the conservation of the natural precipitation. 2. Irrigation should be fcuppMiment-nry fcuppMiment-nry to the' natural precipitation. 3. The natural precipitation over the larger portion of the Grcit Basin, Bas-in, if properly conserved by summer fallowing, is" sufficient to produce crops without irrigation. 4. The amount of moisture found in the soil in the fall depends on the crop grown, the total amount of water wat-er applied during the season, the summer precipitation and, on an irrigated ir-rigated farm, on the date of last irrigation. ir-rigation. 5. On an irrigated farm as high as 95.56 pcy: cent, and on non-irriga-tod farms as high as 93.17 per cent, of the total winter precipitation were found in the upper eight feet of soil. 6. The average of the maximum per cents of the winter precipitation found in the upper eight feet for five years on an irrigated farm was 82.13; for three years on non-irrigated farms, just reclaimed from the desert, was dr. 85. 7. The drier the soil is in the fally the more of the winter precipitation is found in the first eight feet of soil. 8. The water capacity of soils under un-der field conditions is low, usually not above 18 per cent. 9. In the spring irrigated soils to a depth of eight feet arc fully satut'r atcd and non-irrigated soils arc usually us-ually so. 10. A comparatively small portion of the winter precipitation is lost., from the soil by evaporation. tfr. A considerable portion of the winter precipitation passes, down through the soil- below the eight foot limit. 12. In the spring, less than 20 inches of precipitation arc usually found in the upper eight feet of soil;-that is, not more than the precipitation of one and one-half years is stored in the upper eight feet of soil. 13. To make farming without irrigation successful, a considerable per cent of soil moisture -must be carried over from year to year. 14. Fall plowing tends to conserve the natural precipitation. ,'. 15. Fall or winter irrigation 'is ad-visablc ad-visablc on deep soils with good drainage. It should be practiced in moderation. ' , t 16. Lantjs' may be water-logged even if only .a small surplus of water is applied at each irrigation. The' surplus moves to considerable depths until an impervious soil layer is reached, where the accumulation ot water begins. 17. Summer fallowing conserves the soil moisture; the longer the fallow fal-low period, the higher the .per cent of soil moisture. 18. The reason why the beneficial effects of summer fallowing and fall plowing arc not more evident in the soil moisture content is that the water wat-er capacity of most arid soils is small, and that during the winter season a large portion of the water moves below" the eight foot limit, reached by the soil augers. |