14 BUIxL^TIN 1094, TJ. S. DEPARTMENT OF AGEICTJLTTJEE, 



not ready to plow under until in September. The average date for 

 plowing under field peas has been June 20. This is three weeks later 

 than the plowing under of rye, but the fallow period is more com- 

 parable than it could be with cowpeas. Rye, being ready to plow 

 under three weeks earlier than peas, has a fallow period that much 

 longer, and there is that element of difference in addition to the dif- 

 ference in the character of the crop. It is a difference, however, that 

 is inherent in the nature of the crops and can not well be avoided. 

 The average yield of wheat in rotation No. 92 is 14.9 bushels and in 

 rotation No. 56, 15.5 bushels. Again, in'this pair the higher yield is 

 from the rotation having kafir instead of corn two years before the 

 wheat. The difference, however, is too small to be significant. 

 Rotation No. 92 has no record for 1908, as winter wheat was omitted 

 from it by error. It was seeded to spring wheat, but the yield can 

 not be used in comparisons with winter wheat. The average yield 

 of the two plats following peas used as green manure is 15.2 bushels 

 per acre. This is 0.2 bushel more than the average of the two 

 plats following rye used as green manure. Each of the plats on peas 

 has yielded more than one of the plats on rye, but less than the other. 



The evidence presented by the wheat crop alone is not sufficient to 

 distinguish any difference between a legume and a cereal as green 

 manure. Any minor difference there may be is of little significance 

 in comparison with the fact that neither one has produced yields as 

 high as the less expensive bare fallow and only barely or not quite 

 equal to those obtained from the best methods of preparation follow- 

 ing a wheat crop. With the longer fallow period enjoyed by the 

 green-manure plats it seems that their yield should exceed that 

 following a wheat crop and more nearly approach that of the still 

 longer period of the bare fallow. This is their general behavior at 

 most drj'-land stations. 



Two other 4-year rotations contain green manure. Rotations 

 No. 53 and No. 54 are similar to No. 51 and No. 92, with the positions 

 of the corn and green manures exchanged. In these two the barley 

 is on green manure and the wheat on disked corn ground. Rotation 

 No. 53 is rye for green manure, barley, corn, and winter wheat, and 

 rotation No. 54 is peas for green manure, barley, corn, and winter 

 wheat. The average yield of wheat in rotation No. 53 is 14 bushels 

 and in No. 54, 16.2 bushels per acre. This apparently shows a clear 

 advantage of the legume over the cereal as a green manure that was 

 not shown in the rotations where wheat immediately followed the 

 green manure. The wheat in one of these rotations yields less and in 

 the other more than wheat following wheat on early-f aU plowing, but 

 less in each than wheat f ollomng wheat on subsoiling or early listing. 

 They of course yield markedly heavier than wheat following wheat 

 on late-fall plowing. 



