REVIEW QUESTIONS 283 



soil at the time of plowing have upon the condition of the seed 

 bed ? 326. What effect does an excess of moisture have upon the 

 plowing and working of clay soils? 327. In what condition 

 should the seed bed be left as to fineness ? 328. What is gained 

 by fining and moderately firming the seed bed ? 329. Why is 

 aeration of the soil necessary? 330. Why do different soils re- 

 quire different amounts of aeration? 331. Under what conditions 

 can the seed bed be prepared without plowing? 332. On what 

 kinds of soil is such a practice not advisable? 333. When is it 

 advisable to mix the sub soil with the surface soil? 334. When 

 is it not advisable to mix the surface soil and sub soil? 335. 

 How can the plowing and the cultivation of the soil best be carried 

 on to destroy weeds? 336. In what way does cultivation influ- 

 ence bacterial action in the soil? 337. What classes of com- 

 pounds in the soil are subject to bacterial action? 338. How does 

 the action of bacteria affect the supply of available plant food ? 

 339. What is meant by the inoculation of soils? 340. In what 

 two ways can this be accomplished? 341. What soils are most 

 improved by inoculation ? 342. What soils are least in need of 

 inoculation ? 343. What other treatment must often be combined 

 with inoculation? 344. Why do different crops require different 

 cultivation ? 345. How can the best kind of cultivation for a crop 

 be determined? 346. How can soils best be cultivated to prevent 

 washing and gullying? 347. What treatment should such soils 

 receive to be permanently improved? 348. What relationship 

 exists between bacterial diseases of soils and crops? 349. What 

 treatment should soils receive to prevent bacterial diseases? 350. 

 How can the spreading of bacterial diseases through infected seed 

 be prevented? 351. Why must the sanitary condition of a 

 soil for crop production be considered? 352. What effects do 

 some forms of fungi have upon soils? 353. In what way does 

 thick or thin seeding affect plant growth? 354. What effect does 

 abnormal crowding of plants have upon growth? 355. How 

 would you determine the most advantageous quantity of seed for 

 crop production ? 356. How would you determine the most suit- 

 able crop for production upon any soil? 357. What should be 

 the aim in the selection of crops for soils? 358. Why should the 

 crop selected vary with different types of soil ? 359. What is the 

 inherent fertility of soils? 360. What is the cumulative fertility 

 of soils? 361. How can the total fertility of soils be best in- 

 creased? 362. Describe soils of the highest fertility. 363. Why 

 must the amount of plant food as well as the physical condition of 

 the soil be considered in the improvement of soils ? 364. What 

 relation does the fertility of the soil bear to any agricultural 

 system ? 



