AMELIORATION OF LAND 95 



be assumed, satisfactory results, but at 

 present it is on the whole rather rare to 

 find land being thus treated. The quantity 

 used was often as much as 20 or 30 tons per 

 acre, and the labour of digging, carting, and 

 spreading this amount involved a high outlay 

 that few farmers would now care to face. 



The effects of applying lime in any form 

 may thus be shortly summarized. It attacks 

 the humus with the ultimate formation of 

 nitrates, and where land is rich in organic 

 matter this is probably its main effect. It 

 also reacts upon the natural silicates in the 

 soil and liberates a certain amount of potash, 

 which then becomes available as plant food. 

 Lime also tends to sweeten soils, that is to 

 say, it neutralizes organic acids and induces 

 an alkaline reaction, a condition of things 

 which is inseparable from high fertility. By 

 neutralizing acids, lime also makes soil 

 unsuitable for the life of the organism that 

 causes finger-and-toe in turnips and other 

 cruciferous plants. Lime has also useful 

 physical effects on soil, making clay more 

 friable and therefore more easily worked, 

 and raising the absorptive power of lighter 

 soils, but it is doubtful whether these results 

 alone will often justify the heavy expenditure 

 necessary to secure them. 



