Quantifying soil water effects on nitrogen mineralization from soil organic matter and from fresh crop residues

摘要: A loamy sand was incubated with and without addition of carrot leaves at six different water contents ranging from 6% to 20% (g 100 g–1 dry soil) N mineralization monitored during 98 days. We calculated zero- first-order rates for in the unamended soil residue-amended soil. Although strongly affected by moisture, were still important content (corresponding permanent wilting point), particularly Soil recalculated as tension percent water-filled pore space (%WFPS) a parabolic, logistic Gaussian-type function fitted relation between content, %WFPS or pF. Water potential less suitable parameter than either describe influence on mineralization, because extremely sensitive changes range pF values 1.5 2.5. In Gaussian model yielded an optimum 56% which is slightly lower cited literature. more influenced fresh crop residues. This could be explained limitation microbial population decomposing residues, due The effect contained residues most pronounced lowest treatments. retention curves both undisturbed repacked determined suggested that extrapolation results obtained laboratory incubations, using disturbed soil, field conditions will difficult unless bulk density effects are accounted for, case use %WFPS.