Supplying Soil Needs 



179 



FIG. 



137. The white heaps consist of lime that is ready to be spread 

 over the field. 



ing effects : (i) In clay soil it binds the fine particles Five bene- 

 together into larger particles. Thus the clay becomes the use'of 

 like a sandy soil. It loses its stickiness and does not lime 

 bake so badly. It becomes easier to cultivate. (Exp. 5.) 

 (2) It furnishes calcium, one of the ten elements that 

 are essential plant-food materials. (3) It " sweetens " 

 a sour soil. (See page 34.) (4) It is useful to the bene- 

 ficial bacteria in the soil, as these cannot thrive in a sour 

 soil. (5) It aids decay and the formation of humus. 

 Soils that are limed need to have enough organic matter 

 added to them to keep up the supply of humus, the 

 decay of which is hastened. 



The word " lime " as used by farmers may mean any Kinds of 

 one of the following compounds : (i) burnt lime or 

 " quicklime," such as is used by plasterers; (2) water- 

 slaked or " hydrated " lime, made by putting water on 



lime 



