Mechanisms of Soil Aggregates Stability in Purple Paddy Soil under Conservation Tillage of Sichuan Basin, China

摘要: Ridge culture is a special conservation tillage method, but the long-term influence of this system on soil aggregate-size stability in paddy fields largely unknown southwest china. The objectives paper are to evaluate aggregates and determine relationship between SOC aggregate stability. Soil samples at 0-20 cm layer were adopted from (16 yr) field experiment including conventional tillage: plain culture, summer rice crop winter upland under drained conditions (PUR-r), ridge without tillage, fallow with floodwater annually (NTR-f), (NTR-r), wide (NTRw-r), respectively. determination distribution involves assumptions that can be categorized terms their size water (slaking resistance). Experimentally procedure slaked capillary-wetted pretreatments; subsequent slaking treatment >0.250 mm size. WSMA NMWD applied simulate breakdown mechanisms for studying based resistance soil. results showed amount aggregates-size was greatly observed fraction 2~6.72 (more than 50%) capillary-wetting pretreatment. proportion macro-aggregates (>0.25 mm) higher treatment. Minimal differences wetting observed, while significant found culture. ranked order NTR-r>NTRw-r>NTR-f>PUR-r, NTRw-r>NTR-r>NTR-f>PUR-r, There positive correlation concentrations wetting, low exposure lack rice/rape-seed stubble inputs caused declines aggregation organic carbon, both which make susceptible erosion. Adoption no-tillage integrated rotation mulch significantly alter concentration, suggesting it valuable practice carbon sequestration