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Fig. 1. Concentrations of inorganic (P-i), inorganic and enzymatically hydrolyzable organic P (P-i+e), and total P (P-t) in sequentially extracted 1 M HCl fractions of Alabama pastoral Hartselle soils with 0-yr (PLS0), 15-yr (PLS15), and 20-yr (PLS20) poultry litter applications and in Alabama arable Decatur soils with no-tilled soybean (NTSoy), no-tilled corn (NTCorn), conventional soybean (CTSoy), and conventional corn (CTCorn) cropping systems. Values are averages ± standard deviations (n = 6 for poultry litter soils; n = 4 for others).
