PREPARATION OF SOILS FOR CROPS 305 



of crops, all of the inherent fertility should be utilized to 

 the best advantage, and cumulative fertility should be 

 added so that the stock of total fertility may be increased. 

 Soils of the highest fertility are those which are com- 

 posed of a large amount of silt or particles of equivalent 

 value, well drained, but sufficiently retentive of mois- 

 ture for crop production, and of good capillarity. Such 

 soils are usually deposited by water ; they are uniform 

 in texture, of great depth, and contain large amounts of 

 organic matter rich in nitrogen and minerals contain- 

 ing all of the essential elements of plant food. When 

 these soils are cultivated, the organic matter readily 

 undergoes decay with liberation of plant food. 



360. Balanced Soil Conditions. A high state of 

 fertility necessitates a balanced condition of the phys- 

 ical and chemical properties of a soil. Some soils are 

 of good texture and have all the necessary physical 

 requisites for crop production, but fail to produce good 

 crops because of a scant supply of the essential elements 

 of plant food. Other soils contain the necessary plant 

 food but are unproductive because of poor physical 

 condition. Soils may be unproductive on account of 

 either chemical or physical defects, causing the various 

 factors of soil fertility to be unbalanced. In the cul- 

 tivation of a soil it should be the aim to discover any 

 defect and then to apply the necessary corrective 

 measures. Soil problems are extremely varied in char- 

 acter, and the cultivator of the soil should seek aid jointly 



