Show CRITICAL PERIODS Certain Times When Nothing Impedes Im-pedes Growth of a Crop Should Be Determined If Possible at What Stage of Growth Plants Are Most Likely to Be In Need of Water Prof F D Farroll of the office of grain Investigations United States department de-partment of agriculture superintendent superintend-ent of experimental station nt Nophl Utah at the recent Dry Farm Congress Con-gress held at Billings Mont discussed the Importance of certain critical periods peri-ods In dry and crop production He said In part Tho most casual observation of the behavior of a given crop during I the period of Its growth from tho germination of tho seed to maturity will disclose tho fact that at certain times tho plants all seem to do about equally well nothing seems to impede Im-pede their steady uniform rapid growth On the farm during theso times the variations In the character of tho soil or In its condition of tilth appear to have no effect on the crop all over tho field tho crop grows rapidly and uniformly And in an experimental ex-perimental field no differences at rlbutahlo to different methods of tillage til-lage to variety characteristics to various rates or times of planting etc can ho observed In short there are times In the life of a crop when everything seems to favor its growth and when all the crop requires is to be left unmolested Such periods as theso are comparatively negligible i I from the standpoint of both the farmer farm-er and tho agricultural Investigator But these times of absolute prosperity pros-perity for a field of plants aro usually short and Infrequent especially on the dry lands Before the crop has matured It Is practically certain to experience several periods In which the plants aro subjected to conditions of tho most trying severity These conditions may be due to disease soil crusting frost soilblowing etc but most frequently In tho really prim I sections tho difficulty arises i drouth It Is when one or more of these unfavorable conditions exist hat the excellence or the Inferiority of the methods mulled bv the farmer nn nnu appears Also during these times tho process of natural selection tho survival of the fittest and the elimination elimi-nation of the weakIs most active TIs statement applies with equal truth to tho farmers themselves ando and-o the plants in their fields For tho purposes of this discussion we shall designate these durations Critical Periods and with a view to calling special attention to their importance In dryland crop production this paper has been prepared Prof Farrell cited examples to cluclfote his definition of a critical period and continued As to the selection of a location and the choice of crops the total annual an-nual amount of distribution throughout through-out the year and especially among time growing months should invariably invari-ably be taken Into account Moreover More-over as Indicated by our experience with alfalfa it should be determined If possible at what stage of growth the plants of a crop are most likely to need an abundance of water Tills being known it should bo determined whether in the section under consideration consid-eration the necessary moisture could be made available at tho proper time In other words It is unwlso to say that wheat for example can be successfully suc-cessfully grown In a given country because be-cause that country receives an average aver-age annual rainfall of 12 inches or even 20 Inches It must bo known whether the country Js frequently subjected to what would bo critical periods for tho crops to be grown there The length and Intensity of these periods also should be considered consid-ered |