Leituras
Stamey & Smith (1964) Soil Science 97 (183-186)
Johnson (1987) Journal of Soil and Water Conservation Society 43(3): 155-160
Sparovek & Schnug (2001) SSSAJ 65:1479-1486
Sparovek & De Maria (2003) Scientia Agricola 60(2): 409-416
Stamey & Smith (1964) Soil Science 97 (183-186)
Johnson (1987) Journal of Soil and Water Conservation Society 43(3): 155-160
Sparovek & Schnug (2001) SSSAJ 65:1479-1486
Sparovek & De Maria (2003) Scientia Agricola 60(2): 409-416