红壤坡地新开发果园土壤有机碳迁移对不同管理措施的响应

为探究在南方红壤区不同管理措施对于新开发果园土壤有机碳迁移的影响,以典型红壤坡地柑橘园(建园2年)为研究对象,监测评估自然降雨背景下清耕(CB)、稻草全覆盖(CS)、萝卜花生轮作(CRP)、三叶草条带覆盖(CCS)、三叶草全覆盖(CC)和苔藓覆盖(CT)6种管理措施对开发初期果园水土流失和土壤有机碳迁移的影响。结果表明:(1)6种管理措施CB、CS、CRP、CCS、CC和CT的径流量分别为7.88,4.45,4.64,3.24,3.25,4.70 m³,与CB相比,CS、CRP、CCS、CC和CT措施下截流效益分别为43.51%,41.10%,58.94%,58.82%,40.38%,产沙量分别为71.35,21.27,31.03,14.24,14.18,35.05 kg,产沙量与CB相比分别减少70.18%,56.51%,80.04%,80.13%,50.87%;(2)泥沙有机碳流失强度分别为CB(20.75 g/m²),CS(4.78 g/m²),CRP(8.68 g/m²),CCS(3.52 g/m²),CC(3.38 g/m²),CT(9.94 g/m²),相比于对照组CB分别减少76.94%,58.16%,83.01%,83.71%,52.11%;(3)泥沙有机碳和DOC流失强度均与径流量呈显著正相关关系(R²分别为0.412和0.419)。地面管理措施主要通过调控地表径流的产生来影响红壤坡地新开发果园土壤有机碳的迁移。综合来看,三叶草条带覆盖和全覆盖在抑制土壤侵蚀和土壤有机碳迁移损失方面效果较明显。研究结果可为南方红壤区新开发果园水土流失和土壤有机碳迁移损失的防控提供科学依据。

Response of Soil Organic Carbon Migration to Different Management Measures in Newly Developed Orchards in Red Soil Slope

In order to explore the impacts of different management measures on soil organic carbon migration in newly developed Citrus reticulate-based orchards in southern red soil regions, the effects of six management measures on soil erosion and soil organic carbon migration in orchards under the background of natural rainfall were monitored and evaluated, including clear tillage (CB), straw mulch (CS), radish peanut rotation intercropping (CRP), Trifolium strip mulch (CCS), Trifolium mulch (CC) and Bryophyta mulch (CT) in the young Citrus reticulate-based orchards (two years old) located in red soil slope land. Our results showed that: (1) The runoff production of 6 management measures CB, CS, CRP, CCS, CC and CT were 7.88, 4.45, 4.64, 3.24, 3.25 and 4.70 m³, respectively. Compared with CB, the runoff reduction benefits under CS, CRP, CCS, CC and CT measures were 43.51%,41.10%,58.94%,58.82% and 40.38%, respectively; the sediment production was 71.35, 21.27, 31.03, 14.24, 14.18 and 35.05 kg, and the sediment yield was reduced by 70.18%, 56.51%, 80.04%, 80.13% and 50.87%, respectively. (2) The loss intensity of sediment organic carbon was CB (20.75 g/m²), CS (4.78 g/m²), CRP (8.68 g/m²), CCS (3.52 g/m²), CC (3.38 g/m²) and CT (9.94 g/m²), respectively, which decreased by 76.94%, 58.16%, 83.01%, 83.71% and 52.11% compared with CB. (3) The loss intensity of sediment organic carbon and dissolved organic carbon was positively correlated with runoff production (R²=0.412 and 0.419, respectively). Surface management measures affected the migration of soil organic carbon in newly developed orchards in red soil slope mainly by regulating surface runoff generation. In conclusion, both the Trifolium strip mulch (CCS) and Trifolium mulch (CC) had obvious effects on inhibiting soil erosion and soil organic carbon migration loss. This study can provide a scientific basis for controlling soil erosion and soil organic carbon migration loss in newly developed orchards in red soil region of Southern China.