XITROGEX IX AGRICtXTUEE. 183 



three or four days, and a six-tined fork is a good implement for 

 this purpose. 



Sulphate of Ammoxia. Nitrate of Potash. Xitrate of 

 Soda. — The first of these is a by-product of works where coal 

 is used for tlie raanufacture of gas, and is one of the principal 

 soarces supplying nitrogen. It looks like rather coarse salt, and 

 is marketed in barrels, or larger casks, up to huge tierces weighing 

 from a thousand to fifteen hundred pounds. It is readily soluble 

 in water, but does not waste in the air. Nitrate of potash (salt- 

 petre) is usually too dear a source to be available for procuring 

 nitrogen. Nitrate of soda is found in the interior of Chili, on the 

 surface and in the soil. It is a remarkably stimulating fertilizer. 

 If there is much rain it will waste before plants can take it up. 

 Mr. Lawes advises to apply it only when not more than three feet 

 in depth of the soil will be moistened. From one hundred to two 

 hundred pounds per acre is excellent to give grass a start in the 

 spring ; it should not be applied until the leaf has made a growth 

 of three or four inches. In dry seasons it is better and cheaper 

 than sulphate of ammonia, as the latter needs a degree of moist- 

 ure to make plant food. Still, on the whole, the sulphate of 

 ammonia is considered the better investment; for, Jirst, it is not 

 likely to be lost in the atmosphere ; second, it is not too soluble ; 

 third, it has the power of clinging to the ingi'edients of the soil ; 

 clay will hold it persistently, and even pure sand, washed with 

 water, will retain a large portion of it ; and, fourth, its ammonia is 

 readily changed into nitric acid by the action of the soil. Nitrate 

 of ?oda, we are told, "is ver}* liable to be adulterated with white 

 sand or broken quartz, and with salt or the cheap potash salts. 

 . The purchaser should see that it dissolves entireh' in 

 water, and does not taste distinctly of salt." 



I sometimes use sulphate of ammonia to hurry along crops of 

 onions that are rather backward, spreading two hundred pounds 

 per acre just before the\' begin to bottom, and working it into the 

 soil with a slide-hoe. 



Castor-Pomace. — This is a waste product of the West, being 

 the cake left after the oil has been pressed from castor beans. In 

 using it care should be taken to keep it where animals cannot 

 reach it. The men who spread it ought to walk with the wind ; 

 for, though not poisonous, it is extremely unpleasant in contact with 

 the eyes or month. It is a favorite manure for tobacco. I have 

 used car-loads of it in former 3"ears, on general crops, with good 

 results. 



