MAINTAINING SOIL FERTILITY 281 



much as upon manuring, fertilising, fallowing and 

 the like. , A really comprehensive discussion of 

 soil fertility should consider all the ways in which 

 a soil is handled or is acted upon by natural forces, 

 as well as means of enriching it, and of conserving 

 native richness. The methods of handling soil and 

 their relation to productivity have been discussed 

 in previous chapters. The remaining chapters 

 will be devoted to the methods of enriching soils 

 and husbanding natural resources. 



Many Views. There are many views, and un- 

 avoidably many conflicting views, on this great 

 problem. Some seek to solve it in one way and 

 some in another. Certain men lay most stress on 

 the texture of the soil and the movement of soil 

 water as a measure of the producing power of a 

 soil. Others emphasise thorough tillage above 

 all else. Another says, "Grow clover and plow it 

 under; it is the key to fertility." Others lay 

 stress upon good texture and the addition of humus. 

 We hear something of inoculating the soil to 

 make it fertile. Even now the most commonly ac- 

 cepted views on soil fertility have been challenged 

 by an eminent soil physicist whose conclusions, if 

 accepted, will almost revolutionise our views about 

 the effect of manures and fertilisers on soils. In 

 addition to this honest difference of opinion, there 

 are many quack remedies for preserving or restor- 

 ing soil fertility. The following pages present 

 the views most commonly accepted at .this time. 



THE NATIVE RICHNESS OF SOILS 



Plant food is not fertility, but it has a very im- 

 portant influence on fertility. A soil's power to 

 produce crops is very rarely measured by the 



