[Effects of consecutive application of composted sewage sludge on active organic nitrogen fractions in the sandy fluvo-aquic soil.].

A field experiment was conducted with sandy fluvo-aquic soil under wheat-maize rotation system during 2012 to 2016 in Henan Province, with four treatments: Chemical fertilizer (CK), composted sewage sludge (CS) 15 t·hm(CS), 30 t·hm(CS), 45 t·hm(CS). We investigated the effects of CS on soil active organic nitrogen and its allocation ratio. Results showed that CS significantly enhanced soil water content, decreased soil pH, increased contents of soil organic carbon and total nitrogen (TN) and available nutrients.