农业工程学报
農業工程學報
농업공정학보
Transactions of the Chinese Society of Agricultural Engineering
2015年
19期
135-141
,共7页
陆银梅%李忠武%聂小东%黄斌%马文明%肖海兵
陸銀梅%李忠武%聶小東%黃斌%馬文明%肖海兵
륙은매%리충무%섭소동%황빈%마문명%초해병
径流%土壤%有机碳%坡面%可蚀性%泥沙态
徑流%土壤%有機碳%坡麵%可蝕性%泥沙態
경류%토양%유궤탄%파면%가식성%니사태
runoff%soils%organic carbon%slope%erodibility%sediment-bound
探明坡面径流和土壤可蚀性对土壤有机碳流失的影响,对于研究土壤有机碳固定和区域碳循环有重要作用。该文通过野外径流小区模拟降雨试验研究不同雨强(30~100 mm/h)和耕作条件下(翻耕和免耕)土壤有机碳流失过程及其与坡面径流和土壤可蚀性的关系。结果表明,坡面产流过程对泥沙态有机碳流失过程具有明显影响,除大雨强条件下泥沙态有机碳流失速率在10~30 min呈现短时间峰值外,各径流小区泥沙态有机碳流失过程与坡面产流过程总体变化趋势基本一致,均表现为产流开始后,其流失率随降雨历时延长而增加,而后逐步趋于平稳,但坡面产流过程对径流有机碳流失过程无明显影响;坡面径流率大小影响土壤有机碳流失,坡面径流率变化能解释80%土壤有机碳流失的变化,坡面径流率与土壤有机碳流失呈线性正相关关系,且坡面径流率对泥沙态有机碳流失的影响比其对径流有机碳流失的影响更明显;土壤可蚀性对土壤有机碳流失的影响是非线性的,且土壤可蚀性指标越大,土壤有机碳流失率越大,但土壤可蚀性对土壤有机碳流失的影响存在有限性。坡面径流和土壤可蚀性是土壤有机碳流失的重要影响因素。
探明坡麵徑流和土壤可蝕性對土壤有機碳流失的影響,對于研究土壤有機碳固定和區域碳循環有重要作用。該文通過野外徑流小區模擬降雨試驗研究不同雨彊(30~100 mm/h)和耕作條件下(翻耕和免耕)土壤有機碳流失過程及其與坡麵徑流和土壤可蝕性的關繫。結果錶明,坡麵產流過程對泥沙態有機碳流失過程具有明顯影響,除大雨彊條件下泥沙態有機碳流失速率在10~30 min呈現短時間峰值外,各徑流小區泥沙態有機碳流失過程與坡麵產流過程總體變化趨勢基本一緻,均錶現為產流開始後,其流失率隨降雨歷時延長而增加,而後逐步趨于平穩,但坡麵產流過程對徑流有機碳流失過程無明顯影響;坡麵徑流率大小影響土壤有機碳流失,坡麵徑流率變化能解釋80%土壤有機碳流失的變化,坡麵徑流率與土壤有機碳流失呈線性正相關關繫,且坡麵徑流率對泥沙態有機碳流失的影響比其對徑流有機碳流失的影響更明顯;土壤可蝕性對土壤有機碳流失的影響是非線性的,且土壤可蝕性指標越大,土壤有機碳流失率越大,但土壤可蝕性對土壤有機碳流失的影響存在有限性。坡麵徑流和土壤可蝕性是土壤有機碳流失的重要影響因素。
탐명파면경류화토양가식성대토양유궤탄류실적영향,대우연구토양유궤탄고정화구역탄순배유중요작용。해문통과야외경류소구모의강우시험연구불동우강(30~100 mm/h)화경작조건하(번경화면경)토양유궤탄류실과정급기여파면경류화토양가식성적관계。결과표명,파면산류과정대니사태유궤탄류실과정구유명현영향,제대우강조건하니사태유궤탄류실속솔재10~30 min정현단시간봉치외,각경류소구니사태유궤탄류실과정여파면산류과정총체변화추세기본일치,균표현위산류개시후,기류실솔수강우력시연장이증가,이후축보추우평은,단파면산류과정대경류유궤탄류실과정무명현영향;파면경류솔대소영향토양유궤탄류실,파면경류솔변화능해석80%토양유궤탄류실적변화,파면경류솔여토양유궤탄류실정선성정상관관계,차파면경류솔대니사태유궤탄류실적영향비기대경류유궤탄류실적영향경명현;토양가식성대토양유궤탄류실적영향시비선성적,차토양가식성지표월대,토양유궤탄류실솔월대,단토양가식성대토양유궤탄류실적영향존재유한성。파면경류화토양가식성시토양유궤탄류실적중요영향인소。
Clarifying soil organic carbon (SOC) loss plays a vital role in studying SOC sequestration and regional C cycling. In order to investigate effects of overland flow and soil erodibility on SOC loss, field simulated rainfall experiments were conducted at Soil and Water Conservation monitoring station (111°22′ E, 27°03′ N) located in the Shuangqing district in Shaoyang City of Hunan Province, in the hilly red soil region of southern China. Rainfall events were performed in 2012 on 4 chisel tillage plots with rainfall intensities of 100, 80, 40 and 30 mm/h (CT-1, CT-2, CT-3 and CT-4) and 2 no tillage plots with rainfall intensities of 80 and 30 mm/h (NT-1 and NT-2), respectively. Field plots (5 m length × 2 m width) were designed at a sloping land with a slope of 10°, and all the rainfall events lasted 60 min since the runoff began. Runoff and sediment samples were collected every 6 min for measuring runoff volume, sediment weight, and concentration of runoff-dissolved organic C and sediment-bound organic C. The results showed that sediment exports averaged 2.400, 1.400, 0.960, 0.290, 0.200 and 0.014 g/(m2·s); Sediment-bound organic C exports averaged 0.009, 0.007, 0.010, 0.002, 0.003 and 0.0001 g/(m2·s) in CT-1, CT-2, NT-1, CT-3, NT-2, and CT-4, respectively. The sediment and associated SOC loss in high-intensity rainfall events were significantly (P<0.05) higher compared to low rainfall intensity events, coinciding with changes in runoff. However, runoff-dissolved organic C loss rate presented the higher values in CT-1, CT-2, and CT-3 than the other plots, different from change in runoff rate. Runoff rate of all the plots increased first and then within 12 min. The sediment loss rate of CT-1, CT-2, and NT-1 firstly increased and then decreased within 30 min, subsequently kept a stable value with rainfall duration; The sediment loss rate of CT-3, CT-4, and NT-2 was steady during the rainfall event. Sediment-bound organic C loss rate of CT-1, CT-2, and CT-3 sharply increased and then decreased within 30 min, subsequently stayed a stable value with rainfall duration; The change of sediment–bound organic C loss rate in CT-3, CT-4, and NT-2 was relatively steady. Runoff-dissolved organic C loss rate of CT-1 appeared two peak value at 25 min and 45 min, respectively, and both CT-2 and CT-3 appeared the peak value at 30 min. Runoff-dissolved organic C loss rate of NT-1, and NT-2 kept a stable value within 35 min and then appeared the peak value at 45 min, while runoff-dissolved organic C loss rate of CT-3 was steady during the whole rainfall event. This indicated that the loss process of sediment-dissolved organic C was similar to that of runoff except for the peak values appeared during 10-30 min in high-intensity rainfalls, and the sediment-bound organic C loss rate firstly increased and subsequently kept a relatively stable value. The results above demonstrated the magnitude of runoff affected SOC loss; Loss process of runoff had an obvious effect on that of sediment-bound organic C, but was not highly correlated with that of runoff-dissolved organic C. A positive linear relationship between SOC loss rate and runoff rate was shown. The regression analysis reveals variability of runoff could explain 80% of the variance in SOC loss, and runoff rate had a larger effect on sediment-bound organic C than runoff-dissolved organic C. In addition, the results showed that the soil erodibility had a nonlinear effect on SOC loss. Greater soil erodibility indicator could result in higher SOC loss rate, but the growth rate of SOC loss gradually decreased with the increase of soil erodibility indicator, which indicated the effect of soil erodibilty on SOC loss was limited. These observations led to the conclusion that runoff and soil erodibility were two significant impact factors of SOC loss.