4 BULLETIN 214, TJ. S. DEPARTMENT OE AGRICULTURE. 



where winter rye had been turned under the year before. In 1915 

 A will be in wheat, B in winter rye, C in oats, and D in corn. 



In the present stage of development of the work, the effect of the 

 immediately preceding crop and of the method of handling its stubble 

 in preparing the seed bed greatly overshadows the effects of the rota- 

 tions considered as units. Some of the rotations are calculated to 

 conserve or to accumulate fertility and organic matter in the soil, while 

 others may perhaps deplete it, but on the naturally fertile soils of the 

 Plains such results are not strongly evidenced in the first years of 

 treatment. The controllable factors that exert the greatest influence 

 on production are water supply, physical condition of the seed bed, 

 and a recognized if not understood effect of the immediately preceding 

 crop. The crop of a single year brings the land back so near to uni- 



A S.P jj 



A S.F U 





A LATE FP^ 



A S.P. w 







A S.P. v 





A s.p. 





A cop»,s.p. 



A cop/y,s,p 



B FP. g] 



B F.P. | 



B F.P. *| 



B F.P. S 



B PP. %. 



B p.p. £ 



B WHEAT, F , 

 D.C. /4 



B WHEAT, t _ 

 D. C. /O 



c CORN, s.f 



C WHEAT, 



S.F. 



C WHEAT S.P. 



C OATS, S.F. 





C bap ter, 

 s.f: 



C FLAX t S.E 



C W. RYE, 

 F.P. 



C PEAS f P. P. 



fallowed 



D FALLOWED 



D FALLOWED 



D FALLOWED 





P FAUOWEO 



D FALLOWED 



D OATS. 

 CM. 



D OATS, 6. ft. 



£ SUB SOILED 



£ SUB SOI LED 



£ SUBSOILED 



£ SUBSOILED 





£ SU85QJLEQ 



£ SUB50/LED 



£ CORH, S.P. 



£ COP/V f S.P. 



F LISTED 



F LISTED 



F LISTED 



F listed 





F L/STPO 



£ ItSTFD 



B OATS, 



D.C. /£ 



B OAT J, ,_ 

 D.C. // 



G LISTED 



6 listed 



A COPH, F.P. 



A FALLOWED 





A cop/*, 

 p.p. 



A cop*, 



C W.RYE, 

 F.P 



C PEAS, P.P. 



A OATS .. 

 D.C. 40 



A <%%? 49 





B BARLEY, „ 

 DC 6 



3 KIT'S 





B WHEAT. - 

 P.P. 3 



B WHEAT , 

 D.C. / 



D WHEA T, 



/> WHEATjG.M. 



B corn 

 p.p. 



B WHEAT, 

 D.C. 



r, OATS, F.P. 



C OATS, P.P. 





Q OATS, P.P. 



£ OATS, P.p. 



A «wj«« 



^ COP/V, f . Pi 



A OATS 

 F.P 



A FALLOWED 



A conn f.p. 



J COPN, S.P. 





A COPM,S.P. 



A COP/Y,S-P. 





B r/T/9 



*?.?.• /8 



B corn _ ' 



M.SS.P €8 



a OATS, - 

 " FAL. 8 



B OATS, D.C. 



B WHEAT, 2 





* ??' 7 



* t T P S > 9 



P FALLOWED 



C FALLOWED 



C WHEAT, D.C 



C WHEAT, 

 F.P. 



C WHEAT, F.P. 



C m OATS, S.P. 





C BARLEY. 

 S.P. 





C WHEAT, 



D OATS, FAL. 



^ WHEAT, FAL. , 



A CORH,F.P. 



A W. IV HE AT, 

 " OH RYE 



A OATS, F.P. 



£ 0POME 





A CLOfEP 



a broke: 



£ BROMe. 



J ALFALFA 



B W r"e £AT " 43 



* ST' 64 



B ""°» 30S 



B OATS 





8 OATS, 

 O/f SOD 



g BPO/fE 



B OATS. 



g OATS 



C OATS, 



C W.RYE, 

 F.P. 



Q WHEAT, 



r CORN. ,_ 

 c S.P. /0 





S. P. // 



« *s& /2 





c s°p"-4/ 



L s.p. 42 



A cop 



A Mts'.P. 



J CQPH, F.P. 



n WHEAT. 

 D.C 





WHEAT, 





OATS, F P. 



D WHCAT, 



D WHEAT, D.C. 



*.&* 4S 



" %£?' 67 



* "o.% VC -45 



£T BPOAtE 





£ CLOVER 





£ COR/I, S. P. 





£ BPOAfE 



£ ALFALFA, 



C OATS, SOD. 



C WHEAT 





C OATS, CM. 











D.C. 





p BPOM£ 



f ALFALFA. 



Fig. 2.— Diagram of the dry-land rotation field at the Judith Basin Field Station. The lettering shows the 

 cropping practiced in 1914. The explanation of abbreviations used is as follows: D. C. = disked (corn 

 land), Fal.,or S.;F.=summer tilled, F. P.=fall plowed, G. M.=green manured, M.=manured, S. P.= 

 spring plowed. 



f ormity in these factors that their probable residual effect is not great 

 enough in the work in hand to introduce serious error into a study as 

 here made. 



It seems advisable at the present time to prepare a series of bulletins 

 discussing in each the results secured with one crop, as determined by 

 the treatment of the land in only the one year preceding its growth. 



CLIMATIC CONDITIONS. 



The annual precipitation at the various stations varies from about 

 15 to 21 inches. The average increases from north to south and from 

 west to east. An increase in the average daily evaporation from north 

 to south prevails. The rainfall is fluctuating in character. Years of 

 heavy rainfall may follow years when it is deficient, and vice versa. 



