156 Bulletin 154. 



and animal excrements, — nitrogen, phosphoric acid and potash, 



— are not so available as they are in skillfully manufactured 



commercial fertilizers, yet they are usually computed at com- 

 mercial prices, for there should be some convenient and uniform 

 standard upon which to base comparisons and with which to 

 make calculations. On the other hand, manures furnish avail- 

 able humus, and a mulch if they are spread upon the surface, and 

 they also tend to increase the water-holding power of the soil, 

 and to improve its texture or physical condition. In many cases 

 it is believed that these benefits are a full equivalent for the less 

 available fertilizing constituents of manures as compared with 

 commercial fertilizers. When the soil has a reasonable amount 

 of easily available plant-food, it is probable that such may be the 

 case, but the ultimate welfare of plants depends so much on a 

 healthy, vigorous start and abundant root development, that the 

 more quickly-acting commercial fertilizers may be more valuable 

 than the slower- acting farm manures, whenever the land is 

 deficient in readily available plant-food. Careful observations 

 and experiments can only determine the relative values of the 

 constituents found in fertilizers and manures. The final pro- 

 ductive value, as evidenced in the harvest, depends so much on 

 the skill of the farmer, on climate, character of the plant, and 

 rainfall, that it can never be certainly predicted whether profit 

 or loss w411 result in the purchase and application of nitrogen, 

 potash and phosphoric acid in any form. One thing is certain, 

 that the careful husbanding of farm manures, and the applica- 

 tion of them in reasonable quantities in almost any form, result 

 in improved fertility and increased profits in the final income. 



Bulletins Issued Since the Close of the Fiscal Year, June 30, 1898. 



150. Tuberculosis in Cattle and its Control. 



151. Gravity or Dilution Separators. 



152. Studies in Milk Secretion. 



153. Impressions of Fruit-Growing Industries. 



154. Table for Computing Rations for Farm Animals. 2d Ed. revised. 



155. Second Report on the San Jose Scale. 



156. Third Report on Potato Culture. 



157. Grape-vine Flea-beetle. 



158. Source of Gas and Taint Producing Bacteria in Cheese Curd. 



159. An Effort to Help the Farmer. 



160. Hints on Rural School Grounds. 



161. Annual Flowers. 



162. The Period of Gestation in Cows. 



163. Three Important Fungous Diseases of the Sugar Beet. 



164. Peach Leaf-Curl. 



165. Ropiness in Milk and Cream. 



166. Sugar Beet Investigations for 1898. 



