Abstract Plastic-film mulch is used for increasing soil temperature and reducing water evaporation to enhance productivity in semiarid regions worldwide; however, its effects on soil organic carbon (SOC) level and stability are not clear. We tested hypotheses that increasing soil temperature and moisture by plastic-film mulch with an increase of carbon input would increase the accumulation of heavy-fraction SOC (HFOC) and decrease the mineralization potential of HFOC. Soils were sampled at 0–45 cm depth from four treatments: (i) no mulch and no straw incorporation, (ii) mulch only, (iii) straw incorporation only, and (iv) straw incorporation plus mulch. All treatments were cultivated with C4 maize (Zea mays L.) under ridge–furrow management continuously for nine years in a field previously planted with C3 crops in a cold environment. Proportionately to the increased aboveground biomass, root biomass in the 0–20 cm depth increased under mulch compared to no mulch. Nine years later, mulch reduced both maize-derived (new) and C3-crop-derived (old) light-fraction SOC (LFOC) stocks only at 0–15 cm soil depth compared to no mulch, regardless of whether straw was incorporated or not, reflecting the increased decomposition due to increased temperature and moisture in mulched soils. Mulch increased new HFOC stock at 0–30 cm soil depth relative to no mulch. These indicated that the faster decomposition of labile LFOC with increasing plant input under mulch relative to no mulch was paralleled by an enhancement in the accumulation of stable HFOC in mulched soils. Mulch enhanced the benefits of straw incorporation in terms of increasing the accumulation of new HFOC. Over nine years, the average sequestration rate of new HFOC at 0–45 cm soil depth was 204 (±18) and 266 (±10) kg ha−1 yr−1 without and with mulch, respectively, in non-straw-incorporated plots, and 514 (±14) and 752 (±18) kg ha−1 yr−1 without and with mulch, respectively, in straw-incorporated plots. Old HFOC was unaffected by mulch or straw incorporation. Overall, mulch did not change the total SOC storage in the top 45-cm soil. Mulch decreased the mineralization potential of new HFOC under laboratory incubation compared to no mulch, indicating that the new HFOC was more decomposed in mulched soils. We concluded that increasing soil temperature and moisture by using plastic-film mulch with high plant input increases the accumulation of stable HFOC in maize croplands.

中文翻译：

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天然 13C/12C 比率特征表明，塑料薄膜覆盖种植增加了玉米种植土壤中与矿物质相关的有机碳积累

摘要 地膜在全球半干旱地区用于提高土壤温度和减少水分蒸发以提高生产力；然而，其对土壤有机碳（SOC）水平和稳定性的影响尚不清楚。我们测试了以下假设：随着碳输入的增加，通过塑料薄膜覆盖物增加土壤温度和湿度会增加重馏分 SOC (HFOC) 的积累并降低 HFOC 的矿化潜力。从四种处理方式在 0-45 厘米深度处对土壤进行取样：（i）无覆盖物且不掺入秸秆，（ii）仅覆盖，（iii）仅掺入秸秆，以及（iv）掺入秸秆加覆盖物。所有处理均在先前在寒冷环境中种植 C3 作物的田地中，在垄沟管理下使用 C4 玉米 (Zea mays L.) 连续栽培 9 年。与增加的地上生物量成正比，与没有覆盖物相比，覆盖物下 0-20 厘米深度的根生物量增加。九年后，与没有覆盖物相比，覆盖物仅在 0-15 厘米土壤深度减少了玉米衍生的（新）和 C3 作物衍生的（旧）轻质 SOC (LFOC) 储量，无论是否掺入了秸秆或不是，反映了由于覆盖土壤中温度和湿度增加而导致的分解增加。相对于没有覆盖物，覆盖物在 0-30 厘米土壤深度增加了新的 HFOC 存量。这些表明，相对于没有覆盖物，随着覆盖物下植物投入的增加，不稳定 LFOC 的分解速度更快，同时稳定 HFOC 在覆盖物土壤中的积累增加。覆盖物在增加新 HFOC 的积累方面增强了秸秆掺入的好处。九年来，0-45 cm 土壤深度处新 HFOC 的平均封存率分别为 204 (±18) 和 266 (±10) kg ha-1 yr-1，在无和有覆盖物的情况下，在非秸秆掺入地块中，和 514 (±14) 和 752 (±18) kg ha-1 yr-1 分别在没有和有覆盖物的情况下，在掺入稻草的地块中。旧的 HFOC 不受覆盖物或稻草掺入的影响。总体而言，覆盖物没有改变顶部 45 厘米土壤中的总 SOC 储存量。与没有覆盖物相比，覆盖物在实验室孵化下降低了新 HFOC 的矿化潜力，表明新 HFOC 在覆盖土壤中分解得更多。我们得出的结论是，通过使用具有高植物投入的塑料薄膜覆盖物来增加土壤温度和湿度，可以增加玉米农田中稳定 HFOC 的积累。