METHODS OF APPLYING MANURE. 59 



3. There must have been considerable excess wastage on plots N, even 

 had the rate of application been smaller, although, of course, the financial 

 loss would have been less. 



4. The conclusion which appears to me to be fully justified by the 

 results obtained to date (1919) is that the manure for the crop of the 

 following season should be incorporated with the soil by the plow or 

 harrow after the removal of the crop in the late fall, if practicable, rather 

 than spread upon the surface to remain until spring. 



5. There can be little doubt that the excess wastage on plots N would 

 have been less on land which was more nearly level than that used in 

 this experiment, but the land surface in Massachusetts and throughout 

 a large part of the New England States is so broken that the proportion 

 of land so level that there is no wash over the surface is comparatively 

 small. 



6. The earHer start and more rapid growth on plots S, especially during 

 the later years of the experiment, are a decided advantage, and in many 

 cases go far to insure a superior crop on account of the fact that the 

 moisture supply in the early part of the season is more surely adequate 

 to the needs of the crop, as a rule, than later. 



Yet in one other way the earher start and more rapid growth which 

 doubtless occur in the root system as well as in the tops help to insure 

 a good crop. I would refer also to the fact that crops which develop 

 early and rapidly are far more likely to escape serious injury by insect 

 enemies than those starting late or gi'owing slowly, both because better 

 able to resist attacks of such enemies, and because capable of quickly 

 replacing tissues which are eaten or injured. In the case of some para- 

 sitic diseases, also, the plant making an early start and rapid growth is 

 less likely to be seriously injured. 



7. The earlier maturity of the crop on plots S constitutes an important 

 advantage in favor of such practice as will prevent excessive loss of plant 

 food. This of course is particularly true of crops thriving at relatively 

 high temperatures, such, for example, as Indian corn and soy beans. 



8. There can be no doubt that there is some wastage of nitrogen from 

 winter-spread manure, and nitrogen is, as a rule, the most costly of the 

 different plant-food elements; but reduction of the amount of wastage 

 of nitrogen through the practice of piUng and spreading the manure to 

 be immediately incorporated with the soil in the spring is not the only 

 nitrogen advantage connected with that practice. Particular attention 

 has been called to the far greater proportion of clover on plots S than on 

 plots N. Under these relative conditions it appears certain that a much 

 greater amount of nitrogen must be taken from the air, and either made 



