REVIEW QUESTIONS 269 



process of fattening? 17 r. Explain the course of the nitrogen of 

 the food during digestion and the forms in which it is voided in 

 the manure. 172. Compare the solid and liquid excrements as to 

 constancy of composition and amounts produced. 173. What is 

 meant by the manurial value of food ? 174. Name five foods with 

 high manurial values; also five with low manurial values. 175. 

 What is the usual commercial value of manures compared with 

 commercial fertilizers? 176. How does the manure from young 

 and from old animals compare as to value? 177. How much 

 manure does a well-fed cow produce per day? 178. What are the 

 characteristics of cow manure? How do horse manure and cow 

 manure differ as to composition, character, and fermentabilitv ? 

 179. What are the characteristics of sheep manure? 180. How 

 does hen manure differ from any other manure? 181. Why should 

 the solid and liquid excrements be mixed to produce balanced 

 manure? 182. What volatile nitrogen compound may be given off 

 from manure ? 183. What may be said regarding the use of human 

 excrements as manure ? 184. Is there any danger of an immediate 

 scarcity of plant food to necessitate the use of human excrements 

 as manure ? 185. To what extent may losses occur when manures 

 are exposed in loose piles and allowed to leach for six months ? 

 186. What two classes of ferments are present in manure? 187. 

 Explain the workings of the two classes of ferments found in 

 manures. 188. How much heat may be produced in manure dur- 

 ing fermentation ? 189. Is water injurious to manure? 190. How 

 should manure be composted ? What is gained? 191. How does 

 properly composted manure compare in composition with fresh 

 manure? 192. Explain the action of calcium sulphate in the pre- 

 servation of manure. 193. How does manure, produced in open 

 barnyards, compare in composition with that produced in covered 

 sheds? 194. When may manure be taken directly to the field and 

 spread? 195. How may coarse manures be injurious to crops? 

 196. W 7 hat is gained by manuring pasture land? 197. Is it econom- 

 ical to make a number of small manure piles in afield? W 7 hy? 

 198. At what rate per acre may manure be used? 199. To 

 what crops is it not advisable to add stable manure? 200. How 

 do a crop and a manure produced from that crop compare in 

 manurial value? 201. Why do manures have such a lasting effect 

 upon soils? 202. Why does manure from different farms have 

 such variable values and composition ? 203. In what seven ways 

 may stable manures be beneficial ? 204. W T hat may be said regard- 

 ing the importance of phosphorus as plant food ? W r hat function 

 does it take in plant economy ? 205. How much phosphoric acid 

 is removed in ordinary farm crops ? 206. To what extent 

 is phosphoric acid present in soils? 207. What are the sources 

 of the soil's phosphoric acid ? 208. What are the commer- 



