No. 6. DEPARTMENT OF AGRICULTURE. 4-1 



favorable for nitrification, it f'omV)ines with the minora! matter of th( 

 soil and produces liumates, it acts as a mulch and prevents the evap'' 

 ration of water. 



The farmer should have so accurate a knowldege of the fertilizing 

 power of his manure and the phj-sical and chemical requirements oi 

 the various soils he cultivates and crop® he raises that he can always 

 apply it to make it subserve the best purposes, by adding plant food 

 forming hunuites, making inert plant food available, producing nitr' 

 fication, changing the texture of the soil, raising the temperature 

 increasing the water holding capacity, producing chemical actioi. 

 and always having some plant food available when the plant ma> 

 need it. 



COMMERCIAL FERTILIZER. 



However economically we may conserve plant food it will in manj 

 soils become exhausted beyond the power of the plant to obtain whai 

 it needs for its perfect growth; and then we will have to use som« 

 form of commercial fertilizer. Lime is the commonest of the fertih* 

 zers and is an essential element of plant food. The average crop 

 requires from 8 to 75 pounds per acre and whenever lime is deficient 

 plants lack vitality and can not withstand drought or anything tha"* 

 hinders the vital processes. 



Lime acts both chemicall}' and physically on the soil. Chemically 

 it unites with the humic acid and forms humates of lime, it liberate* 

 potash and aids nitrification. Physically it improves the capillarity 

 of the soil and cements soil particles and prevents washing. h 

 many soils liaving an ample supply of lime a light application of air 

 slaked lime will prove very beneficial. Commercial fertilizer is mad. 

 mostly of substances containing plant food in concentrated forn- 

 Nitrate of soda, kainit and dissolved phosphate rock are the sub 

 stances commonly used for making what is called a complete fert' 

 lizer. 



For nitrate we sometimes find such substitutes as dried blood, 

 flesh meal, tankage, fish scrap (both of W'hich contain phosphoric 

 acid), leather, waste hair and seed residue. For dissolved rock w* 

 sometimes receive the more desirable dissolved bone, bone black and 

 Thomas slag; and for kainit we find wood ashes, tobacco stems an^ 

 even feldspar substituted. 



Nitrate of soda when pure contains 16.49 per cent, nitrogen. Dis 

 solved phosphate rock contains 12 to 14 per cent. Phosphoric aci<^ 

 and kainit contains about 12 per cent potash. 



Suppose we desire to make a ton of what is usually known as f 

 complete fertilizer, we would mix: 



250 lbs. nitrate of soda, furnishing 40 lbs. nitrogen. 

 450 lbs. kainit, furnishing 56 lbs. potash. 



1300 lbs dissolved rock, furuishing 183 lbs. phosphoric acid. 

 29 



