Effects Of Tillage And Stubble Retention Management On Soil Infiltration Characteristics In The Qingyang Loess Plateau

A rainfall simulator was used in the field to compare the infiltration characteristics under different tillage and stubble management after winter wheat harvesting in the Qiangyang Loess Plateau of China, in 2004 - 2005. There were six treatments, namely no-till (NT);no-till with stubble retention (NTC);shallow till (LT, 10cm);shallow till with stubble retention (LTC);deep till (DT, 20cm);deep till with stubble retention (DTC). The rainfall intensity was 66 mm/h. Results showed that cumulative rainfall infiltration was over 93% under stubble retention during 40 min of rainfall. The final steady infiltration rate was over 60 mm/h. Tillage increased rainfall infiltration;the final steady infiltration rate under DT treatment (26.4 mm/h) was twice as much as under LT treatment (12.96 mm/h), and 4 times greater than under NT treatment (6.35mm/h). DT treatment increased infiltration by 21% and 28% during 20 min of rainfall ran, and by 31% and 33% during 40 min of rainfall compared with those under LT and NT treatments, respectively.Water stable aggregate (>0.5mm) under NTC treatment significantly higher (P< 0.001) than all other treatments. A significant differences was found under tillage treatment without surface cover between before and after rainfall simulator running (P< 0.001), indicating tillage could increase the soil erosion.The second rainfall simulation experiment was conducted in July 2005 after 5 years' crop rotations under conservation tillage. The rainfall intensity was 78mm/h. The crop sequence was maize—winter wheat—soybean—maize. There were 4 treatments, namely conventional tillage (T);conventional tillage with stubble rotation (TS);no-till (NT) and no-till with stubble retention (NTS). The final steady infiltration rate was similar for all treatments except NTS, ranged from 11-17mm/h. Infiltration rates for NTS treatment was 57mm/h after 51min of rainfall, which was 5.2 times greater than T treatment (11 mm/h ), 3.4 tunes greater than TS treatment (17 mm/h), and 4.8 times greater than NT treatment (12 mm/h). The cumulative runoff was 22.9mm and 20.1mm for T and NT treatments, while the runoff under NTS treatment was only 2.6 mm. In summary, no-till with stubble retention increased infiltration and reduced runoff, thus reduced soil erosion and improved sustainability.