EFFECT OF MANURE ON GRASSES 275 







The other lesson is of a field not manured but deeply 

 plowed and cultivated 20 times, then fertilized with 

 various artificial fertilizers, no manure given, and seeded 

 to grass under the "Clark method." A good stand of 

 grass was secured and the first year saw a heavy crop 

 of hay. The following year, however, the yield was 

 but ordinary and the third year saw the field in worse 

 condition than those about it. The evident lesson is 

 that the deep plowing, the frequent cultivation during 

 warm weather preparatory to seeding the crop, used up 

 a good deal of the humus needed to make the land have 

 moisture-holding and bacteria-growing qualities, so that 

 the last state of that land was worse than the first. It 

 may be that had this field been top-dressed with manure 

 after the first year it would have maintained itself, but 

 it is clear that chemicals alone on soils deficient in humus- 

 will not make permanently for large yields of grains or 

 clovers. 



Manure in Soils like Yeast in Bread. Manure, 

 vegetable matter decaying in the soil, acts much as does 

 yeast in the moist dough ; it starts ferments, bacterial 

 processes, some of them understood, some of them not. 

 For example, we once bought a poor field and at once 

 re-sold half of it to a neighbor. Our half we treated 

 with acid phosphate, tankage, good plowing and a very 

 slight sprinkling of manure. The land was then sown 

 to clover with oats or barley. Our neighbor imitated us 

 exactly except that, having no manure, he omitted it. 

 We secured a good stand and a fine heavy growth of 

 clover. Our neighbor secured a fair stand and a light 

 growth. The amount of manure applied was insignifi- 



