181 



in that form to most crops, except those of the leguminous class, on 

 whose roots are gall-like swellings known as root tubercles, which 

 are formed under the influence of micro-organisms living in the 

 soil. It has been found that the presence of these bacteria and 

 root tubercles enables some plants to draw from the vast stores of 

 nitrogen in the air a supply which will enrich the ground in that 

 valuable element and enable it to grow more abundant crops. 



The more common source of nitrogen on the farm or at the 

 orchard is found in farmyard manure, which consists of 



/-Water ... 70 



FAKM YARD \ Organic Matter 27 Nitrogen, '4 to "65 per cent. = 9 

 MANURE. 1 to 151bs. per ton. 



( Ash ... ... 3/ Phosphoric Acid, '2 to '5 per 



j cent. =4 to lOlbs. per ton. 

 100 ) Potash, -3 to '6 per cent. -5 to 



( 131bs. per ton. 



A good dressing per acre, 5 to 10 tons. 



The other forms of organic nitrogen, i.e., the nitrogen of animal 

 and vegetable matters which is chemically united to carbon, hydrogen, 

 and oxygen, are 



Ammoniacal Guanos. Are the best of the concentrated complete 

 manures, as they have nitrogen 8 to 12 per cent., phosphates 15 to 

 25 per cent., and a little potash. It is a very valuable manure for 

 most crops, but is rather expensive. It more nearly resembles farm- 

 yard manure in its composition than other artificial manures, and 

 its great use is to replace this manure when it is scarce. A good 

 dressing, 2 to 3 cwts. to the acre. 



Dried Blood. The refuse of slaughter house, being a very 

 complex substance, it is also a very valuable manure, contains 

 nearly as much dry matter as flesh e.g., about 23 per cent. When 

 dried without other substances it contains about 10 per cent, water 

 and 8 to 10 per cent, ammonia, with a little phosphate and traces of 

 potash. It is one of the best forms of manures in light lands, and 

 is not readily washed away. Often mixed with gypsum, which 

 decreases its value ; useful for making composts. Fair dressing per 

 acre, 3 to 4cwt. 



Dried Nightsoil or Poudrette. Contains 2 to 4 per cent, 

 nitrogen, 3 per cent, phosphate, and 1'5 per cent, potash ; often 

 mixed with gypsum and earth, which reduces its value. A bulky 

 manure which would hardly pay to carry a long distance, when 

 freight and carriage is a consideration. 



Other forms of organic nitrogen are those of seeds, such as 

 cotton seed cake and other oleaginous seeds after the extraction of 

 the oil. 



Leather and peat are also classed as nitrogenous manures, but 

 they are comparatively slow in their effect on vegetation, and for 

 that reason are less valuable. 



Nitrogen occurs as minerals and notably ammonium salts and 

 nitrates and nitrites. 



