REVIEW QUESTIONS 281 



are lime fertilizers applied ? 254. What is the result when land 

 plaster is used in excess? 255. Explain the action of salt on soils. 

 256. When would it be desirable to use salt as a fertilizer? 257. Is 

 soot of any value as a fertilizer? Explain its action. 258. Are sea- 

 weeds of any value as fertilizer? 



CHAPTER X. 



259. What is a commercial fertilizer? An amendment? 260. 

 To what does the commercial fertilizer industry owe its origin ? 



261. Why are commercial fertilizers so variable in composition? 



262. Explain how a commercial fertilizer is made. 263. Why are 

 the analysis and inspection of fertilizers necessary ? 264. What 

 are the usual forms of nitrogen in commercial fertilizers? 265. Of 

 phosphoric acid and potash ? 266. How is the value of a commer- 

 cial fertilizer determined? 267. What is gained by home mixing 

 of fertilizers? 268. What can be said about the importance of 

 tillage when fertilizers are used ? 269. How are commercial fer- 

 tilizers sometimes injudiciously used? 270. How may field tests 

 be conducted to determine a deficiency in available nitrogen, phos- 

 phoric acid, or potash? 271. To determine a deficiency of two 

 elements? 272. How are the prelinilbary results verified ? 273. 

 Why is it essential that field tests with fertilizers be made? 274. 

 Under what conditions does it pay to use commercial fertilizers ? 

 275. What is the result when commercial fertliizers are used in 

 excessive amounts? 276. Under ordinary conditions, what special 

 help do the following crops require : Wheat, barley, corn, potatoes, 

 mangels, turnips, clover and timothy? 277. In what ways do 

 commercial fertilizers and farm manures differ? 



CHAPTER XI. 



278. Does the amount of fertility removed by crops indicate the 

 nature of the fertilizer required ? In what ways are plant ash 

 analyses valuable ? 279. Explain the action of plants in render- 

 ing their own food soluble. 280. Why do crops differ as to their 

 power of procuring food? 281. Why is wheat less liable to need 

 potash than nitrogen ? 282. What position should wheat occupy 

 in a rotation ? 283. In what ways do wheat and barley differ in 

 feeding habits ? 284. What can be said regarding the food require- 

 ments of oats ? 285. Corn removes from the soil twice as much 

 nitrogen as a wheat crop, yet a wheat crop usually thrives after a 

 corn crop. Why ? 286. What help is corn most liable to need in 

 the way of food? 287. What position should flax occupy in a 

 rotation ? On what soils does flax thrive best ? 289. What is the 

 essential point to observe in the manuring of potatoes ? 290. What 

 kind of manuring do sugar-beets require? 291. Why should the 



