CAJ | 학술논문

　　研究不同耕作方式对华北农田土壤固碳及碳库管理指数的影响，可为探寻有利于农田固碳的耕作方式提供科学依据。该研究在中国农业大学吴桥实验站进行，试验于2008年设置了免耕秸秆不还田（NT0）、翻耕秸秆不还田（CT0）、免耕秸秆还田（NT）、翻耕秸秆还田（CT）和旋耕秸秆还田（RT）5个处理。研究测定分析了土壤容重、有机碳、易氧化有机碳含量及不同耕作方式下的碳库管理指数。通过对不同耕作方式下0～110 cm土壤的分析，结果表明，随着土层的加深，土壤有机碳含量不断下降，NT显著增加了表层（0～10 cm）土壤有机碳含量，而＞10～50 cm 有机碳含量较其他处理（NT0除外）有所下降，深层（＞50～110 cm）处理间差异不明显；土壤容重与有机碳含量呈显著的负相关关系（P＜0.01）；0～30 cm土层有机碳储量以NT最高，CT与其无明显差异，二者较CT0分别高出13.1%和11.0%，而至0～50 cm土层，CT的碳储量最高，但与NT无显著差异（P＜0.05）；与CT0相比，NT0降低了各层土壤易氧化有机碳含量，而NT则在0～10 cm土层表现为增加；RT、CT分别显著增加了0～10、＞10～30 cm土层的碳库管理指数。结果表明，秸秆还田可改善土壤质量，提高农田碳库管理指数，同时碳库管理指数受耕作方式的影响也较大，尤其是CT和RT；NT通过减少土壤扰动、增加有机质的输入，可提高上层土壤有机碳的储量。
　　연구불동경작방식대화북농전토양고탄급탄고관리지수적영향，가위탐심유리우농전고탄적경작방식제공과학의거。해연구재중국농업대학오교실험참진행，시험우2008년설치료면경갈간불환전（NT0）、번경갈간불환전（CT0）、면경갈간환전（NT）、번경갈간환전（CT）화선경갈간환전（RT）5개처리。연구측정분석료토양용중、유궤탄、역양화유궤탄함량급불동경작방식하적탄고관리지수。통과대불동경작방식하0～110 cm토양적분석，결과표명，수착토층적가심，토양유궤탄함량불단하강，NT현저증가료표층（0～10 cm）토양유궤탄함량，이＞10～50 cm 유궤탄함량교기타처리（NT0제외）유소하강，심층（＞50～110 cm）처리간차이불명현；토양용중여유궤탄함량정현저적부상관관계（P＜0.01）；0～30 cm토층유궤탄저량이NT최고，CT여기무명현차이，이자교CT0분별고출13.1%화11.0%，이지0～50 cm토층，CT적탄저량최고，단여NT무현저차이（P＜0.05）；여CT0상비，NT0강저료각층토양역양화유궤탄함량，이NT칙재0～10 cm토층표현위증가；RT、CT분별현저증가료0～10、＞10～30 cm토층적탄고관리지수。결과표명，갈간환전가개선토양질량，제고농전탄고관리지수，동시탄고관리지수수경작방식적영향야교대，우기시CT화RT；NT통과감소토양우동、증가유궤질적수입，가제고상층토양유궤탄적저량。
Soil organic carbon (SOC) pool plays an important role in mitigating greenhouse gas (GHG) emissions. However, long-term conventional tillage practices can result in significant losses of soil organic matter (SOM), thus inducing an increase in soil erosion and increasing CO2 efflux. In addition, burning straw is another important emission sources of GHG in the North China Plain (NCP). In order to identify the best tillage practices for SOC sequestration under the wheat-maize cropping system in this region, we investigated the effects of tillage on SOC concentration, SOC stock, the carbon pool management index (CMI), and SOC distribution in the soil profile. This study was conducted at the Wuqiao Experiment Station in Hebei Province from 2008. Five different treatments were established, including no-till without straw retention (NT0), conventional tillage without straw retention (CT0), no-till with straw retention (NT), conventional tillage with straw retention (CT), and rotary tillage with straw retention (RT). Soil samples were taken after harvesting of wheat, and soil bulk density (BD), SOC, and labile organic carbon (LOC) were analyzed. The results showed that NT0 significantly increased BD in all soil layers (0~50 cm) (P<0.05). Concentration of SOC decreased with an increased depth (0-110 cm) among all treatments. NT significantly increased the SOC concentration at the topsoil (0-10 cm) compared with the other treatments. Concentration of SOC under NT was 34.4%higher than that under CT0 at 0-5 cm depth. However, SOC under NT was lower compared with other treatments (except NT0) in >10-50 cm, but there was no significant difference among the treatments deep layers (>50-110 cm). The relationship between BD and SOC concentration showed a strong negative correlation. In order to reduce the bias caused by variations in bulk density under different tillage treatments, the equivalent soil mass method was used in calculating SOC stock. At the depth of 0~30 cm, the total SOC stock under NT was the highest (40.73 Mg/hm2) among all the treatments, and there was no significant difference in SOC stock between CT and NT, but those were 13.1%and 11.0%higher than CT0, respectively. However, for the 0-50cm depth, the SOC stock in CT was highest, but no significant difference with NT (P<0.05). Compared with CT0, NT0 reduced the LOC concentration in all soil layers, but NT increased at 0-10cm soil layers. The carbon management index (CMI) under RT were 21.7%and 32.3%higher than NT at 0-5 and 5-10 cm depth, respectively, but no significant difference occurred at both >10-20 cm and>20-30 cm. However, CMI under CT was higher than that under NT, NT0 and CT0 at all soil depths. Results of that indicated that crop straw retention could increase soil quality and increase CMI that was also strongly affected by tillage management. In conclusion, NT reduced soil disturbance and increased the input of SOM, which was beneficial in SOC storage, especially at the surface layers. Nonetheless, the results of this study were based on short-term tillage experiments in SOC concentration/stock. Therefore, a long-time study may reveal the changes in SOC and its mechanism under conservation tillage because of the duration effects. These data also suggest sampling subsoil layers to understand the underpinning processes governing SOC sequestration.