CONCLUSIONS FROM EXPERIMENTS. 



71 



soil by the legumes will in time overcome the advantage which the 

 rye now seems to have. 



(19) Wherever winter wheat can be safely grown it should con- 

 stitute a considerable portion of the small-grain crop. The danger 

 from winterkilling tends to make it a more precarious crop than 

 spring-sown grains. On the other hand, its earlier maturity, which 

 frequently allows it to escape the droughts of early summer, and its 

 higher yield when conditions are favorable give it a marked advan- 

 tage over spring wheat. It should be raised in rotation with other 

 crops. 



When so raised, summer tillage will not usually be necessary or 

 advisable. Under certain circumstances it may be found desirable 

 to summer till, as winter wheat certainly responds much more readily 

 to summer tillage than do spring-sown crops. Summer tillage even 

 for winter wheat can not be recommended as a general or frequent 

 practice in the Great Plains area. It is believed that the plowing 

 under of a green-manure crop early in the season and proper treat- 

 ment of the soil from that time until seeded to winter grain will 

 usually give as good immediate results as summer tillage. There 

 can be little doubt as to the advantage of green manuring over sum- 

 mer tillage in its ultimate effect upon the soil. 



The conclusions concerning summer tillage reached from our 

 investigations throughout the Great Plains area are in general 

 accord with those of Mr. W. P. Snyder, superintendent of the Nebraska 

 Agricultural Experiment Substation, at North Platte, Nebr., and 

 of Mr. W. W. Burr, assistant in dry-land agriculture, detailed to 

 that substation from the Bureau of Plant Industry. We therefore 

 quote from an article prepared by them and published in Bulletin 

 No. 109 of the Agricultural Experiment Station of Nebraska, as 

 follows : 



Ultimate effect of summer tilling. — Frequent summer tilling may be more or less 

 detrimental to our land. The changes which break down the humus in the soil go on 

 very rapidly under the conditions afforded by summer tilling and must exhaust the 

 entire supply more quickly than where some method is practiced which does not 

 furnish so good conditions for the destruction of humus in the soil. 



We feel safe in recommending summer tillage for small grain, especially winter 

 wheat, but advise that a rotation be followed which will keep up the organic matter in 

 the soil and conserve its fertility. Such a rotation will probably use summer tillage 

 on the same field only once during a series of years, and will have a grass, legume, or 

 some green manuring crop which will put back into the soil the organic material taken 

 from it. Where sufficient barnyard manure is to be had, an application of it once during 

 the rotation will probably keep up the humus and conserve the fertility of the soil. 

 Where manure is used it should be applied as evenly as possible on the land, and 

 disked to mix it with the rurface. It should be applied at a time and in such a manner 

 as to be a benefit rather than a harm to the succeeding crop. 



From our experience we can not lay down a definite system of rotation for all con- 

 ditions. The rotations must be worked out to suit the farm where they are to be 

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