EXPERIMENT STATION BULLETINS. 177 



without it, and its influence in developing the carbohydrates, and matur- 

 ing traits, is marked and apparently controlling. 



5. Nitrogen Compounds. Nitrogen is the bottled wine of the vegetable 

 feast. If the term stimulant can be applied to any organization destitute 

 of a nervous system, then nitrogen is the stimulant of plant life. In any 

 of its combined forms it gives depth of color and exuberance of growth 

 to vegetable life, and when in abundant supply it causes the plant to 

 break forth into riotous growth. The great reservoir of nitrogen is the 

 air, but the leaves of plants though constantly bathed in nitrogen, can- 

 not drink in a particle. It is only nitrogen in combination that can be 

 appropriated by the plant, and this enters the plant by the roots and 

 comes from the soil. A small amount is brought to the soil by the rain, 

 washing out the ammonia and nitrates of the air, but the amount is not 

 large, and entirely inadequate to supply a crop. 



A large amount of active nitrogen in the form of nitrates is yearly 

 formed in every well cultivated field, and this is the cheapest way of 

 securing a supply of this costliest element of plant growth. The raising of 

 leguminous crops, like the clovers, is the next cheapest way of securing 

 a supply. 



Combined nitrogen is purchased in three forms; salts of ammonia, 

 nitrate of soda, and organic nitrogen in the form of dried blood, fish 

 scraps, cotton seed meal, etc. 



6. Tankage, is a complex and variable material obtained from the 

 waste residues at the slaughter houses, the garbage collected by the 

 scavengers in cities, etc. These materials are dried, the grease extracted 

 in tanks and this tankage by itself, or mixed with phosphates, potash, 

 etc., is sold as a fertilizer. It is mainly used to give bulk to the concen- 

 trated fertilizers made from bone and rock phosphate. 



LIME. 



Following nitrogen, potash and phosphoric acid, the next most impor- 

 tant material is lime. In soils made by the decomposition of granite 

 rocks, the soil is apt to be deficient in lime. This is manifest in the New 

 England states. In most of the countries of our lower peninsula where 

 the soil is classed in the drift formation, lime is an abundant element in 

 the soil. It is easy to determine this by an examination of the well 

 water. Our water comes by the rain, and is soft, but soaking into the 

 ground it dissolves more or less of the mineral matter of the soil. If the 

 well water of any region is very hard as shown by its action on soap, the 

 hardness being caused by the lime dissolved in the water, such soil con- 

 tains enough lime to supply the needs of crops. Lime may be used in 

 such regions to decompose muck and flocculate clay, but is not required to 

 feed the crops. 



SHALL THE FARMER USE COMMERCIAL FERTILIZER? 



An important question both for farmer and manufacturer. They 

 cost money — a material not too abundant in the farmer's pocket in these 

 times — while there is a large amount of valuable manurial material pro- 

 duced on the farm that costs nothing but a little labor and considerable 

 care in collecting and keeping. The dealer offers a "complete manure," 

 which furnishes three of the thirteen chemicals of agriculture, whereas 

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