Soils: An Introduction to Soils and Plant Growth

acid acre alfalfa ammonia ammonium amount applied approximately areas Aridisols bacteria brown calcium carbonate cations cent chemical clay loam climate coarse color corn crops cubic deficiency depth drainage elements erosion farm feet fertilizer Figure forest grasses Histosols horizon humid humus inches increase infiltration irrigation kaolinite land Laterite layer leaching legumes lime loam loamy magnesium manure medium minerals moist Mollisols montmorillonite nitrate nitrogen organic matter oxide Oxisols parent material particles percentage phosphate phosphorus plant growth plant nutrients plant roots plow pollution pores potassium pounds rainfall rock runoff sample sand sandy loam silt loam slope sodium soil classification Soil Conservation Service soil horizons soil map soil material soil moisture soil orders Soil Science soil structure Soil Survey soil temperature soil test soil texture soluble Source Spodosols Suborder sulfate surface Table tillage trees Tropics U.S. Dept United States Department usually vegetation Vertisols yields