In situ annual nitrogen mineralization predicted by simple soil properties and short-period field incubation

摘要: A typical method to determine nitrogen mineralization is year-round field incubation of undisturbed soil cores. As this technique very laborious, the aim present study was establish less time consuming methods assess annual N mineralization. Options considered were reducing period subsequent incubations than a full year, and prediction using simple (direct) measurements. In situ measured in 74 semi-natural, unfertilized sites under vegetation cover by sequential cores during 2 years. The classify into 14 different plant community types encompass wide range edaphic conditions. high correlation with maintained when restricted early March–mid August (r=0.98). Shorter periods may also be used, as long they lie within 3 months at least. average could predicted accurately mineral pool (Nmin), moisture content pH predictor variables. multiple regression model based on log-transformed values, R2 0.835. Samples (preferably bulked) are best taken March, just before start growing season. Higher Nmin contents (moisture assumed constant) indicated higher rates. (at constant pH) generally lower Soil showed quadratic relation fixed moisture) maximum occurring pH-CaCl2 value 5.5–5.6. appeared most important variable. Even (with reduced conditions), its relationship persisted. Frequently studied factors, such total N, organic matter content, C:N ratio, soluble particle size composition, only low insignificant correlations, although stronger relationships have sometimes been reported. It discrepancy caused smaller conditions usually studied.