268 GUAXO. 



out of all proportion greater than that of farm-yard 

 manure, Avhilst the produce of corn was smaller. It is 

 quite evident that one constituent acting more powerfully 

 in the direction of the formation of straw was supphed to 

 the field in larger proportion in the guano than in the 

 farm-yard manure. Experiments Avith superphosphate 

 (excluding ammonia), or with an ammoniacal salt (exclud- 

 ing phosphoric acid), would have shown to which of 

 these two elements the difference in the produce was 

 owing. 



At Oherhohritzsch the increase of produce was — 



As the quantity of guano used at Oberbobritzsch was 

 about 50 per cent, more than in the preceding expe- 

 riments, no comparison as to amount can be made 

 between the produce of this field and that of the others. 

 What is again remarkable here is the similarity of the 

 condition of this and the Mausegast field ; on both, farm- 

 yard manure gave straw and corn in the proportion of 

 1-2 ; guano, in the proportion of 1-3. As regards the 

 power of the soluble guano constituents to pass through 

 the soil, we find from these experiments the same con- 

 ditions existing as with those of farm-yard manure. At 

 Cunnersdorf and Kotitz the whole guano constituents 

 hardly produced any effect upon the clover crop ; whilst 

 at Mausegast and Oberbobritzsch a perceptible increase 

 was the result. 



Sihcic acid, which gives strength and firmness to stalks 

 and leaves, is not one of the ingredients of guano ; hence, 

 after manuring with guano, the tendency of the cereals to 

 lodge, so much dreaded by agricidturists, is observed on 



