EFFECT OF GUANO ON STKAW PRODUCE. 255 



Cunnersdorf field, and contained, already, an excess of 

 St constituents. The K constituents supplied in the 

 guano constituted a much smaller fraction of the whole 

 store already present in the field than was the case 

 with the Cunnersdorf field, and their effect tended 

 rather to increase the produce of straw than that of 

 corn. 



The application of guano had the effect of producing 

 the same quantity of straw on the Cunnersdorf as on 

 the Mausegast field (5951 and 5979 Ibs.); but the corn 

 reaped from the latter exceeded that obtained from the 

 former by 752 Ibs. The Mausegast field was much 

 richer in K constituents than the Cunnersdorf field. 



At Kotitz the increase of produce was 



Corn. Straw. Eatio. 

 Ibs. Ibs. Ibs. 



By farm-yard manure (229 cwt.) . . . 352 1006 = 1 : 2'8 



By guano (41 libs.) 341 1732 = 1:5 



The effect of guano upon the straw produce was here 

 out of all proportion greater than that of farm-yard 

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

 quite evident that one constituent acting more power- 

 fully in the direction of the formation of straw was 

 supplied to the field in larger proportion in the guano 

 than in the farm-yard manure. Experiments with 

 superphosphate (excluding ammonia), or with an am- 

 moniacal salt (excluding phosphoric acid), would have 

 shown to which of these two elements the difference in 

 the produce was owing. 



At Oberbobritzsch the increase of produce was 



Corn. Straw. Eatio. 

 Ibs. Ibs. Ibs. 



By farm-yard manure (314 cwt.) . . . 452 913 = 1:2 



By guano (616 Ibs.) 938 2812 = 1:3 



As the quantity of guano used at Oberbobritzsch was 

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

 ments, 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, 



