Effects of Soluble Organic N on Evaluating Soil N-Supplying Capacity

摘要: It is important to study the soluble organic N (SON) extracted during water-logged incubation for evaluating soil N- supplying capacity. Soil initial SON and mineral (Nmin), cumulative NH4+-N in leachates incubation, mineralization potentials of both easily decomposable (ND) resistant (NR), their relationships with uptake by crop pot experiment were investigated using 10 kinds farmland soils widely different physical chemical properties on Loess Plateau, China, effects capacity studied. The results showed that average content (23.9 mg kg−1) was 28.8% total 2.4% N. percentage leaching (118.1 46.4%, higher than (28.8%), almost close leachates. ND had correlation N, coefficients 0.92 (P < 0.01, excluding estimating ND) 0.88 including ND), respectively. potential rate constant types. Los-Orthic Entisols Ust-Sandiic lower Eum-Orthrosols. Mineralization fast N-fraction (kD) decreased materials (kR) increased when taken into account. Cumulative a better evaluation index N-supplying capacity, it not only suitable first season crops but also two successive crops. alone satisfactory mineralizable But would be more accurate revealing TSN, some extent, could as an NH4+-N, good indexes especially And permanence N-supply greater significance included.