-(> Food for Plants. 



make iisr of i1. Tliis is done in tlic soil by tliu action of 



certain organisms, under favorable con- 

 Defects and ditions. The weather must he suitable, 

 Losses in the ihu soil in a certain condition; and be- 

 Use of Ordinary sides there are considerable losses of 

 Nitrogens. valuable substance in the natural soil 



process of nitrating such Nitrogen. By 

 unfavorable weather conditions, or very wet or acid soils, 

 nitration may be prevented until the season is too far 

 advanced, hence there may be loss of time, crop and 



money. The quality of nitrogens, such 

 Intrinsic Values as cotton-seed meal, dried fish, dried 

 of All Nitrogens blood, and tankage, is limited by condi- 

 Based on tions similar to those which limit sul- 



Nitrate as the pliate of ammonia. With these sub- 

 Standard, stances, the loss of Nitrogen in its natu- 

 ral air and soil conversion into Nitrate 

 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 

 Unusual three of the plant food elements — Ni- 



Functions of trate. Phosphates and Potash — but not- 



Nitrate. withstanding this imperative need, each 



of the three elements has its special use. 

 There are many cases in which considerations of the 

 special functions of plant food elements become im- 

 portant. For example, a soil may be rich in organic 

 ammonia from vegetable matter turned under as green 

 manure, and through a late wet spring fail to supply the 

 available Nitrate in time to get the crop well started 

 l)efore the hot, dry, summer season sets in. In this case 

 the use of Nitrate of Soda alone will force growth to the 

 extent of fully establishing the crop against heat and 

 moderate drouth. 



