Introductiox to thk Principles of Soil Fertility 



1757 



Dr. W. H. Jordan that " the art of agriculture will rise no higher than the 

 man on the land." The farmer must have a considerable knowledge 

 of the intricate processes that com- 

 bine to make a soil fertile, and his 

 function is to cooperate with natural 

 agencies and to direct their operation 

 in his interest. 



Soil moisture 



Underlying all other requisites for 

 maintaining the fertility of the soil 

 is the proper regulation of the mois- 

 ture supply. It determines the 

 solution of plant-food, the physical 

 condition of the soil, the efficiency 

 of tillage, the effect of fertilizers, and 

 the biological activity. It is there- 

 fore the first thing to be adjusted. 

 This may involve irrigation, as in 

 arid sections; or it may necessitate 

 drainage, as in New York. Always, 

 however, it means the proper hand- 

 ling of the soil in order to conserve 

 and effectively use the water received 

 and stored therein. Large areas of 

 land in New York require better 

 drainage, particularly of the subsoil. 



Lime 



Lime stands second in range of 

 importance. It maintains the proper 

 balance between the acid and the 

 alkaline constituents of the soil. As 

 a result of tillage and cropping, soils 

 may become more acid — a condition 

 unfavorable to most of the important 

 to counteract this tendency. It may be 

 on the local situation of the farm. 



Fig. 2. — ■ Ideal section of soil, showing 

 tlie large distribution of roots in the 

 topsoil and their somewhat smaller 

 distribution in the subsoil. Roots of 

 many plants will penetrate to a depth 

 of several feet if the drainage is good. 

 The topsoil is generally richer hi decay- 

 ing organic matter, which gives it a 

 darker color 



farm crops. Lime is best suited 

 used in different forms, depending 



Organic matter, or humus 

 The maintenance of a fair amount of deca^nng organic matter is essential 

 because of the nitrogen which it contains and which is most economically 



