Mamires and Fertilizers. 27 



soil, allows the free entry of oxygen, and enables the bacteria 

 to fully resume their functions. To allow the soil to get into 

 this condition suggests bad management; a judicious use of 

 fertilizers to supplement the manure, with frequent light appli- 

 cations of powdered limestone (calcium carbonate) would main- 

 tain fertility constantly at its highest pitch. 



Green Manuring is an excellent substitute for farmyard 

 manure where that material is difficult or expensive to obtain. It 

 is good for both light and heavy soils. The crops most suitable 

 for this purpose are mustard, rape, tares, peas, or clover ; these 

 are grown until just before the flowering stage is reached, then 

 rolled down flat and dug or ploughed in. This method of 

 manuring not only adds humus to the soil, but also the soluble 

 plant foods which the crop collects during growth, and which 

 otherwise may be washed out by rains when the soil is left 

 bare. The leguminous or pod-bearing plants have the property 

 of collecting nitrogen from the atmosphere by means of micro- 

 organisms attached to their roots, and when these are used for 

 green manure the soil is additionally enriched. 



Compost Heap. Upon every holding a heap should be made 

 of vegetable refuse, annual weeds, ditch cleanings, road scrap- 

 ings, and other similar materials. To this should be added the 

 ashes and charred refuse from the fires made of tree prunings, 

 tomato and potato haulms, &c. This heap should be turned 

 occasionally, and at each turning a generous sprinkling of 

 powdered limestone should be added. 



In this way a large quantity of valuable fertilizing material 

 can be accumulated in the course of a year. 



NITROGENOUS FERTILIZERS. 



Sulphate of Ammonia is derived from the distillation of 

 coal, during the manufacture of coal gas. It should contain 

 20 per cent, nitrogen, equal to 24| per cent, ammonia. It is a 

 fine salt, generally grey or yellow, sometimes blue, and is 

 easily dissolved in water. It is quite as effective and almost as 

 quick in action as nitrate of soda, but is much more destructive 

 of lime in the soil, and when it is frequently used liming should 

 on no account be omitted. 



