保护性耕作对土壤有机碳含量的影响

Effects of conservation tillage on organic carbon content in soil

为了探讨土壤有机碳对不同耕作措施的响应,进行长期田间定位试验,研究了采用秸秆还田免耕(NTS)、秸秆还田翻耕(TS)、免耕(NT)及常规翻耕(T)4种措施下春小麦-豌豆轮作后土壤有机碳含量的变化,测定了0～5.0 cm、5.1～10.0 cm、10.1～30.0 cm土层中总有机碳含量、腐殖质碳含量和热水溶性有机碳含量。结果表明:轮作10年后,与T处理相比,NTS、TS和NT处理的0～30 cm土层中土壤总有机碳含量、腐殖质碳含量和热水溶性有机碳含量均有不同程度的提高。土壤总有机碳含量、热水溶性有机碳含量及NTS和NT处理下腐殖质碳含量均随土层深度的增加而减少;TS和T处理下,5.1～10.0 cm土层中腐殖质碳含量最高,0～5.0 cm土层中腐殖质碳含量最低。10.1～30.0 cm土层中,TS处理的腐殖质碳含量大于NTS处理。表明秸秆覆盖和免耕均有利于土壤总有机碳、腐殖质碳和热水溶性有机碳的积累。

To investigate the responses of soil organic carbon to different tillage patterns, the variations of or- ganic carbon content in soil after spring wheat-pea crop rotation treated by no-tillage with straw mulch （NTS） , ploughed tillage with straw mulch （TS） , no-tillage （NT） and conventional tillage （T） were studied by long-term field experiments. The total organic carbon content, humus carbon content and hot water soluble organic carbon content in different depths （ 0- 5.0 cm, 5. 1 - 10.0 cm, 10. 1 - 30.0 era） of soil were determined. The results showed that after ten years of crop rotation, the total organic carbon content, hot water soluble organic carbon con- tent and humus carbon content in the soils with NTS and NT treatments declined with the depth of soil layers. In the soils with TS and T treatments, the humus carbon content in 5. 1-10.0 cm depth was the highest, and was the lowest in 0-5.0 cm depth. In soil depth of 10. 1-30.0 cm, the humus carbon content in the soil with TS treat- ment was higer than that in NTS treatmeat. In soil depth of 0-30.0 cm, the total organic carbon content, humuscarbon content and hot water soluble organic carbon content with NTS, TS and NT treatments were all higher than that with T treatment. The results indica- ted that the straw mulch and no-tillage are favorable for the accumulation of total organic carbon, humus car- bon and hot water soluble organic carbon.