Food for tne highest quality, yet there are differences even in this. 

 * For example, Nitrate of Soda is freely soluble in soil liquids 



34 and water, and is the highest grade of plant food Nitrogen; 

 sulphate of ammonia is also soluble in water, but of distinctly 

 lower quality because plants always use Nitrogen in the 

 Nitrate form, and the Nitrogen in sulphate of ammonia must 

 be Nitrated before plants can make use of it. This is done 

 in the soil by the action of certain organisms, under favorable 

 conditions. The weather must be suit- 

 able, the soil in a certain condition; and 

 Losses in the besides, there are considerable losses of 

 Use c Ordinary valuab i e su bstance in the natural soil pro- 

 Nitrogens. cesg Q Ni trat i n g sucn Nitrogen. By un- 

 favorable weather conditions, or very wet or acid soils, Ni- 

 tration may be prevented until the season is too far advanced, 

 hence there may be loss of time, crop and money. The qua- 

 lity of nitrogens, such as cotton-seed meal, 

 Intrinsic Values dried fish> dried blood) and tankage, is 



Nitrogens i imited by conditions similar to those 

 which limit sulphate of ammonia. With 

 Nitrate as the tnese su b s tances, the loss of Nitrogen in 

 Standard. j ts na t ura l a ; r and so il conversion into Ni- 



trate is very great. Perfectly authentic experiments, and 

 made under official supervision, have shown that 100 pounds 

 of nitrogen in these organic forms have only from one-half 

 to three-fourths the manurial value of 100 pounds of Nitrate 

 of Soda. 



Special Functions of Plant Food. 



As stated before, plants must have all three 

 Unusual O f tne pj ant f ood e i ements Nitrate, Phos- 



Functionsof phates and p otas h but notwithstanding 

 itrate. tm - s j m p era ti v e need, each of the three ele- 



ments has its special use. There are many cases in which con- 

 siderations of the special functions of plant food elements be- 

 come important. For example, a soil may be rich in organic 

 ammonia from vegetable matter turned under as green ma- 

 nure, and through a late wet spring fail to supply the avail- 

 able Nitrate in time to get the crop well started before the 

 hot, dry summer season sets in. In this case the use of Ni- 

 trate of Soda alone will force growth to the extent of fully 



