Effect Of Different Tillages Patterns On Soil Organic Carbon Pool In Two Sequence Rotation System With Spring Wheat And Field Pea

Based on a long-term experiment in Dingxi Synthesis Dryland Agriculture Test Station of Gansu Agricultural University, we monitored soil organic carbon,readily oxidizable carbon,microbial biomass carbon and dissolved organic carbon of two sequence rotation system with spring wheat and field pea under different tillage patterns, and alculated the available ratio of soil carbon and carbon pools management index.The experiment contain four treatments, namely conventional Tillage (T), No-Tillage no straw cover (NT), conventional Tillage with Straw incorporated (TS) and No-Tillage with Straw cover (NTS). The main results obtained were listed as follows:(1).Soil organic carbon content of NT and NTS treatments were higher than traditional tillage T of two sequence rotation system. Compared to other treatment, NTS treatments was more conducive to improving and accumulating the content soil organic carbon. In wheat-pea- wheat (P-W-P) rotation fields, the soil organic carbon content for the size of sorting was NTS>NT>TS>T in 0~30cm soil layer. As compared with the T treatments, soil organic carbon content of TS,NT and NTS treatment of were increased by 4.14%,5.22% and 7.45%. In Pea-wheat-peat (W-P-W) rotation fields, the size of sorting was TS>NTS>NT>T. Compared with T, organic carbon content of TS,NT and NTS treatment were increased by 14.65%,7.98% and 12.53%.(2).The organic carbon content of soil surface was significantly higher than other levels under different tillage patterns, and increased with decreasing soil. In wheat-pea- wheat ((P-W-P) rotation fields, the content of organic carbon in the 0~5cm and 5~10cm soil layer was sorting for TS>NTS>NT>T, and in 10~30cm for NTS>TS>NT>T. In Pea-wheat-peat (W-P-W) rotation fields, the organic carbon content of 0~5cm soil layer was sorting for NTS>TS>NT>T, and in 5~10cm and 10~30cm soil layer was TS>NTS>NT>T. The soil organic carbon content of NTS treatment was significantly higher than other treatment of two sequence rotation system in the 0~5cm soil layer.(3).The content of readily oxidizable carbon,microbial biomass carbon and dissolved organic carbon under different tillage patterns had consistent trends as soil organic carbon. Correlation analysis showed thatthe content of readily oxidizable carbon,microbial biomass carbon and dissolved organic carbon of two types rotation had inter-related to each significant level with soil organic carbon in two sequence rotation system. Both readily oxidizable carbon and microbial biomass carbon were characterized to the content of the higher activity carbon, reflecting the effectiveness of organic matter.(4).Conservation tillages can be improved the available ratio of soil carbon. The available ratio of soil carbon was AAC>ABC>ACC under two sequence rotation systems. Compared to traditional tillage, the available ratio of soil carbon of other three s treatments were increased, the available ratio of soil carbon of NTS treatments were higher than other treatments significantly.The results showed that NTS treatments was more conducive to improving the content soil organic carbon and accumulating soil organic matter.(5).Carbon pools management index under NTS, NT and TS treatments higher than the traditional farming treatment, while carbon pools management index in the effects of the surface is relatively large of two sequence rotation systems.In wheat-pea- wheat (P-W-P) rotation fields, CPMI for the size of sorting was NTS>NT>TS>T in 0~30cm soil layer. As compared with the treatments T, CPMI of TS,NT and NTS treatment were increased by 16.58%,18.22% and 43.72%.In Pea-wheat-peat (W-P-W) rotation fields, the size of sorting was NTS>TS>NT>T. Compared with T, CPMI of TS,NT and NTS treatment were increased by 29.24%,14.40% and 47.49%.The contribution of straw cover is greater than tillage patterns, straw cover is a direct cause in carbon pools management index improving.The results of this study showed that combination of rotation and conservation tillage effectively reduced the attenuation effect of traditional cropping systems on soil organic carbon. Soil activity carbon have a great impact on raising the Soil nutrient diversion, and the reflection of the tillage patterns is obvious. NTS treatments which handle a significant increase in content of soil organic carbon was more conducive to soil organic carbon accumulation. Compared to other treatment, NTS treatments is more conducive to the increase in soil organic carbon content and accumulation.