470 MISCELLANEOUS FARM SUBJECTS 



as much potash as phosphoric acid, while wheat requires very nearly 

 as much phosphoric acid as potash. The cereals, grasses, and corn 

 are all heavy consumers of nitrogen, while the legumes may gather 

 most of their supply of nitrogen from the air. Turning under the 

 leaves, roots, and stems of legumes also adds a supply of humus to 

 the soil, which is essential for the maximum effect of fertilizers. By 

 growing crops in rotation which have different fertilizer require- 

 ments the heavy drain on the soil for any one kind of fertilizer is 

 avoided. If legumes are grown in the rotation, as cowpeas after 

 corn or crimson clover after cotton, then the quantity of nitrogen 

 which need be applied in fertilizers to the corn and cotton can be 

 greatly lessened, and in some cases dispensed with entirely, while 

 the increased humus content of the soil, due to the plowing under 

 of the legumes, makes more efficient the fertilizers that are applied. 

 A rotation, therefore, which is planned to minimize the need of 

 commercial fertilizer should include crops of different fertilizer re- 

 quirements alternating with those which add humus and nitrogen 

 to the soil. Rotations which do not include crops that improve the 

 humus content or add nitrogen to the soil neea not be expected to 

 reduce the fertilizer bill. 



RESULTS WITH CERTAIN CROPS. 



It has been shown by certain experiments with nitrate of soda 

 on a number of different crops that, whereas the grain and forage 

 crops, utilizing the nitrate as completely as did the market-garden 

 crops in the same experiment, showed an increase not exceeding in 

 any case a value of $14 per acre, that is, a money return at the rate 

 of $8.50 per 100 pounds of nitrate used, the market-garden crops 

 yielded an increase whose value amounted in the case of one crop 

 to as much as $263 per acre, which was equivalent to a return of 

 approximately $66 per 100 pounds. The striking difference in the 

 returns may easily be accounted for by the fact that in the one in- 

 stance the nitrate nitrogen was built into bulky crop, consuming 

 large quantities of plant food, and possessing a low market value 

 dry hay, bringing, say, $12 per ton, and two tons per acre being 

 considered a good yield while in the other it was built into a 

 material possessing a high market value succulent vegetables, bring- 

 ing as much as hay per ton and the yield being five to ten times as 

 great. It is evident, therefore, that these relations of the cost of 

 fertilizer and of the value of the crop returns are exceedingly im- 

 portant, and deserve careful consideration in the purchase of plant- 

 food constituents. It is for this reason that it is so difficult to secure 

 a reasonable profit from the unsystematic use of fertilizers upon such 

 staple products as wheat, corn, oats, cotton, and tobacco crops quite 

 exhaustive in their manurial requirements and possessing a rela- 

 tively low value. 



On the other hand, the growth of such crops as potatoes, toma- 

 toes, sweet potatoes, forage crops for the dairy, and vegetable crops 

 for the market or cannery by the use of high-priced plant food is 

 more often attended with profit because they are usually crops of 

 high market value and are proportionately less exhaustive. 



