DECIMAL CLASSIFICATION 
631.4 
4. 
42: 
fe 
433 
AL 
An 
A 
46 
Aq 
49 
5 
51 
511 
512 
513 
514 
515 
516 
-517 
52 
Ty 
3A 
B22 
= 3 
3A 
a Wl 
Land, soil 
Soil chemistry 
Chemic properties and constitution of soil 
Composition according to geologic origin 
Inorganic chemistry 
Organic chemistry 
Analysis and experiments 
Methods of investigation: chemic, mechanical 
Soil physics 
Specific weight (gravity) of soil 
Humidity 
Water Ground water 
Soil moisture: hygroscopic, capillary 
Permeability Absorption 
Deserts 
Atmosfere: air, gases 
Temperature 
Warmth of soils 
Soil classification Adaptability 
Alkali lands; soils for special crops, tobacco, etc. 
Soil fertility: maintenance, exhaustion 
Reclamation Erosion 
See also 631.8 Fertilizers 
Soil bacteriology: fungi, microbes, ferments, sterilization 
For soil inoculation see 631.8472 
Soil surveys 
History 
Farm operations 
Soil preparation and working 
Spading, digging, forking 
Plowing, subsoiling 
Blasting, use of explosivs 
Harrowing 
Rolling, planking 
Hoeing, raking, weeding 
Cultivating 
Selection, breeding, etc. 
Selection 
Seed selection 
“ catalogs 
Plant selection 
Nursery catalogs 
Plant breeding 
Fertilization; sterility 
Hybrids Crossing Creat on of new varieties 
Sexual, asexual; binary, ternary, quarternary 
Laws of hybridation; influence of female, of male 
Abnormalities 
Introduction of new kinds 
Acclimatization