PRODUCE OF MANURED AND UNJFANURED FIELDS. 2G7 



the increase of these by the farm-yard manure augmented 

 the straw at the expense of the gram crop. Tlie farm- 

 yard maniu'c contained too little of the K (corn) consti- 

 tuents (nitrogen, phosphoric acid). 



This explains the powerful action of guano (whicli 

 contains chiefly K constituents) upon this field ; the 

 increase of corn by its means was more than double that 

 obtained from farm-yard manure, and a more suitable 

 proportion was estabhshed between the K and S^ consti- 

 tuents in the ground. 



At Mdusegast the increase of produce obtained in 

 1851, above that of the unmanured field, amounted 

 to— 



This field was richer in K and S^ constituents tlian the 

 Cunnersdorf field, and contained, already, an excess of Si 

 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 

 tlie same quantity of straw on the Cunnersdorf as on the 

 Miiusegast field (5951 and 5979 lbs.) ; but the corn reaped 

 from the latter exceeded that obtained from the former 

 by 752 lbs. The Miiusegast field was much richer in K 

 constituents than the Cunnersdorf field. 



At Kbtitz the increase of produce was — 



Com Straw Ratio 



lbs. lb.s. lbs. 



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



By guano (411 lbs.) . . .341 1732 = 1:5 



The effect of guano upon tlie straw produce was liere 



