Figure 6
From: Long-term application of fertilizer and manures affect P fractions in Mollisol
Effect of long-term application of chemical fertilizer, organic manure and straw on the distribution of organic P fractions. * indicates significant difference at P < 0.05 level at the same soil depth, ns indicates no significant difference regarding labile organic P, moderately labile organic P, moderately stable organic P and highly stable organic P concentrations at the same soil depth. CK, no fertilizer application; NPK, chemical fertilizer application; NPK + S, chemical fertilizer plus maize straw incorporation; OM, organic manure application.
