138 AGRICULTURAL EXPERIMENT STATION. [Jan. 



rotation of mixed grasses (meadow growth) and of our 

 next main reliance for fodder, — the corn (maize). Both 

 crops require potash and phosphoric acid, in similar pro- 

 portion (4, potassium oxide, to 1, phosphoric acid), and 

 both require an exceptional amount of the former. There 

 is good reason to assume that the low state of productiveness 

 of many of our farms, so often complained of, is largely due 

 to the fact that crops have been raised in succession for 

 years, which, like those mentioned, have consumed one or 

 the other essential article of plant food in an exceptionally 

 large proportion, and thereby have gradually unfitted the 

 soil for their remunerative production ; while a liberal sup- 

 ply of other important articles of plant food is left inactive 

 behind. As the amount of available plant food contained in 

 the soil represents largely the working capital of the farmer, 

 it cannot be otherwise but that the practice of allowing a 

 part of it to lie idle must reduce the interest on the 

 investment. 



Our personal observation upon the lands assigned for the 

 use of the station has furnished abundant illustration of the 

 above-described condition of farm lands. In one instance it 

 was noticed that a piece of old, worn-out grass land, after 

 being turned under and properly prepared, as far as the 

 mechanical condition of the soil was concerned, produced, 

 without any previous application of manure, an exceptionalh T 

 large crop of horse-beans and lupine, — two reputed fodder 

 crops. A similar observation was made during the past 

 season, when lands, which for years had been used for the 

 production of English hay and corn, were used for the culti- 

 vation of southern cow-pea, serradella, and a mixed crop of 

 oats and vetch, to serve as green fodder for milch cows. 

 The field engaged for the production of these crops was not 

 manured, because it was to be prepared for a special field 

 experiment during the present season. An area of this 

 land, which, under favorable circumstances, would not 

 produce more than six tons of green grass at the time of 

 blooming, yielded nine to ten tons of green vetch and oats, 

 ten tons of green southern cow-pea, and from twelve to 

 thirteen tons of green serradella. The exceptional exhaustion 

 of our lands in potash has been shown by detailed descrip- 



