VII MANURES 53 



air to enter. The addition of a small quantity of lime 

 stirred into a compost heap improves the quality of the 

 manure immensely, as it assists in forming nitre (or nitrate of Nitre. 

 potash), a very important fertilizing substance— which is too 

 expensive, however, to be much used as an artificial manure. 

 It must be remembered in regard to dung and compost 

 heaps that they must not be kept too long, for otherwise the 

 exposure to the weather, and the excessive fermentation, 

 zause a deterioration in the value of the manure as a plant 

 food. 



Waste products of towns and villages form excellent 

 manure, and a good planter will be very glad to obtain them 

 to put on his land. Blood and bones, and other refuse from Nothing 

 slaughter houses, decayed fish, hair, wool, rags, saw-dust, '^^^^^ °^ 

 sweepings, night soil, &c., &c., are all useful to increase the manure to 

 fruitfulness of the soil. They should be put on the land 

 and dug or ploughed into it and they will Avell repay all the 

 trouble and slight expense the planter has incurred in obtain- 

 ing them. 



Greeji Crop Manuring. — By this term is understood the 

 digging or ploughing into the land of growing crops in order 

 that the roots, stems and leaves may decay in the soil and 

 so add to its food constituents. In England and other 

 countries, clover, grass, turnips, rye, mustard, vetches and 

 such plants are raised on lands simply for the purpose of 

 being afterwards ploughed in as green crop manures. This 

 system has been found to answer admirably for restoring 

 the fertility of exhausted soils. It does this by giving to it 

 nitrogen taken from the atmosphere. Recent scientific 

 research has shown that leguminous plants, especially such 

 as clover, peas and beans, have the property of absorbing 

 nitrogen and yielding a large crop of nitrogenous fodder, 

 while the soil by reason of the tillage is often richer and 

 better able to produce other crops. This system is extremely 

 well suited to light fertile soils. It is not advisable to use it 

 where the soil is heavy and retentive. In a modified way it 



