60 



CAMPBELL'S SOIL CULTURE MANUAL 



It is not the purpose of this tool to simply hold up the 

 present normal yield, but to greatly increase the present 

 average yield by from 50 to 250 per cent. 



Experiments repeated over and over again in a variety 

 of soils in the semi-arid belt, have proven conclusively 



Cut No. 3. Showing Soil as the Packer Leaves It. 



that in promoting or developing plant elements or fertility 

 under such conditions that it may be available in large 

 quantities, there must be in the soil just the proper quan- 

 tity of both air and water. If there be too much water 

 and too little air, or too little water and too much air, 

 you cannot secure the best possible results. 



