CHAPTER XIX 



MANAGEMENT OF CLAYS AND DEPLETED SILT LOAMS 



CLAY MANAGEMENT 



CLAY soils are quite the opposite of sands in many respects. 

 Sands are loose and open, while clays are sticky and "tight." 

 Sands are the easiest soils to work, and clays the hardest. The 

 special characteristics of clay soils are due largely to their fine 

 texture. They are composed of thirty per cent and more clay, 

 and the remaining material consists of silt and fine sand. 1 They owe 

 their origin, commonly, to the settling out of fine sediments which 

 have been carried into bodies of water by streams. 



Included in this class are the "gumbo" soils which are so preva- 

 lent in certain sections and localities. Gumbo is usually black 

 clay soil occurring either on river bottoms or flat upland. This 

 soil is more sticky and bakes more easily than any other kind of soil. 



Points in Favor of Clays. Heavy clay loams and clays have 

 a few points in their favor, namely: (a) They are excellent for 

 general farming, for hay and grazing; (b) they are well adapted 

 to clovers and small grains; (c) they can usually supply crops 

 with moisture better than sands during a dry period. 



Special Problems. Clay soils are highly productive when they 

 are given the proper treatment. The special management problems 

 which they present and their solutions are briefly stated in the table. 

 Problems in Clay Management and Their Solutions 



Problems 



Usually cold and wet 

 Difficult to develop good tilth 



Organic matter and nitrogen usu- 

 ally low 



Phosphorus often deficient 

 Subject to washing (erosion) 



Solutions 



Proper surface and subsurface 



drainage 

 Thorough drainage; plow when fit; 



grow grass and pasture 

 Grow legumes and grass; pasture 



Use proper phosphate fertilizers 

 Keep grassed; terrace; deep plow- 

 ing, etc. 



1 The average mechanical composition of nearly 2000 clays is as follows: 

 Forty-two per cent clay, thirty-six per cent silt, sixteen per cent of very fine 

 sand and fine sand, five per cent medium and coarse sand, and one per cent 

 fine gravel. 



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