Improving the Condition of the Soil 



based the use of lime as an improvement. One 

 should not use too much of it, or the usefulness of 

 the nitrogen will be lost. 



Humus rapidly absorbs (and retains) the potash, 

 lime and ammonia of manures ; it forms also 

 humates which are not soluble in water, and prevent 

 them being carried away in the drains by the rain 

 water. Therefore chemical manures should be 

 employed carefully on land which is lacking in 

 humus. 



But when the manures contain muriate of potash 

 and common salt, as is the case with seaweed and 

 kainite, they present a loss in calcium and in 

 magnesium. 



The humus in decomposing produces carbon 

 dioxide, CO2, which helps the decomposition of 

 mineral matters, such as the phosphates and potassic 

 compounds, and makes them more assimilable to 

 the plants. Humus disappears rapidly in arable 

 soil in hot weather, and it is very necessary to 

 import it to the places where it does not exist 

 naturally in sufficient quantities. 



Here is about the quantity of humus present in 

 arable soils : — 



1. Sandy soil, 2 per cent. 



2. Loamy soil, 3 to 4 per. cent. 



3. Clayey soil, 4 to 6 per cent. 



With pasture, clover or seeds on the same soils 

 there would be a higher proportion of humus. 



148 



