[Effect of different tillage managements on black humic fractions and IR spectral feature].

The present study was based on the long-term (10 years) field conservation tillage experiment, in which four tillage treatments were designed as following: Conventional tillage (CT) by moldboard plowing with ridge culture; Rotary tillage with ridge culture (RT); Alternant tillage by rotary on wide row and loosing on narrow row (WN); Rotary tillage plus deep loosing annually (RD). Humic acids were extracted from black soil profiles under these tillage managements. The elements visible spectra and FTIR of HA in black soil were analyzed.