Long‐term changes in soil carbon and nitrogen fractions in switchgrass, native grasses, and no‐till corn bioenergy production systems
Long‐term changes in soil carbon and nitrogen fractions in switchgrass, native grasses, and no‐till corn bioenergy production systems
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柳枝稷、原生草类和免耕玉米生物能源生产系统中土壤碳和氮组分的长期变化
DOI：
10.1002/saj2.20575
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发表时间：
2023
影响因子：
2.9
通讯作者：
Robertson, G. Philip
中科院分区：
文献类型：
--
作者：
Perry, Sophie;Falvo, Grant;Mosier, Samantha;Robertson, G. Philip
纤维素生物能源是一种主要的陆地气候缓解策略，土壤碳（C）储存和氮（N）保存是重要的缓解要素。在这里，我们展示了三种纤维素种植系统下 13 年的土壤 C 和 N 变化：单一栽培柳枝稷 (Panicum virgatumL.)、五种本土禾本科植物混养和免耕玉米 (Zea maysL.)。 12 年间对土壤 C 和 N 组分进行了四次测量。研究结束时 0-25 厘米深度的大块土壤 C 范围为免耕玉米中的 28.4 (± 1.4 se) Mg C ha−1，柳枝稷中的 30.8 (± 1.4) Mg C ha−1，以及原生草中的 34.8 (± 1.4) Mg C ha−1。矿物相关有机质 (MAOM) 占土壤总碳的 60% 至 90%，颗粒有机质 (POM) 占土壤总碳的 10% 至 40%。 12 年来，免耕玉米和柳枝稷下的总碳以及两种碳组分持续存在，而原生草下则有所增加。相比之下，整个系统的 POM N 库存下降了 33% 至 45%，而 MAOM N 仅在免耕玉米中下降，下降幅度不到 13%。 POM N库存下降可能反映了建厂前的土地使用，其中包括早期轮作中的苜蓿和粪肥。根系生产和大量土壤团聚体的形成分别解释了土壤总碳变化的 69% (p< 0.001) 和 36% (p= 0.024)，以及土壤氮变化的 60% (p= 0.020) 和 41% (p= 0.023)，这表明地下生产力和土壤团聚体对于生产和保护土壤碳以及保存土壤氮的重要性。柳枝稷和原生草之间的差异也表明对植物多样性的依赖。生物能源作物的土壤碳和氮效益在很大程度上取决于根系生产力和建厂前的土地利用。
Cellulosic bioenergy is a primary land‐based climate mitigation strategy, with soil carbon (C) storage and nitrogen (N) conservation as important mitigation elements. Here, we present 13 years of soil C and N change under three cellulosic cropping systems: monoculture switchgrass (Panicum virgatumL.), a five native grasses polyculture, and no‐till corn (Zea maysL.). Soil C and N fractions were measured four times over 12 years. Bulk soil C in the 0–25 cm depth at the end of the study period ranged from 28.4 (± 1.4 se) Mg C ha−1in no‐till corn, to 30.8 (± 1.4) Mg C ha−1in switchgrass, and to 34.8 (± 1.4) Mg C ha−1in native grasses. Mineral‐associated organic matter (MAOM) ranged from 60% to 90% and particulate organic matter (POM) from 10% to 40% of total soil C. Over 12 years, total C as well as both C fractions persisted under no‐till corn and switchgrass and increased under native grasses. In contrast, POM N stocks decreased 33% to 45% across systems, whereas MAOM N decreased only in no‐till corn and by less than 13%. Declining POM N stocks likely reflect pre‐establishment land use, which included alfalfa and manure in earlier rotations. Root production and large soil aggregate formation explained 69% (p< 0.001) and 36% (p= 0.024) of total soil C change, respectively, and 60% (p= 0.020) and 41% (p= 0.023) of soil N change, demonstrating the importance of belowground productivity and soil aggregates for producing and protecting soil C and conserving soil N. Differences between switchgrass and native grasses also indicate a dependence on plant diversity. Soil C and N benefits of bioenergy crops depend strongly on root productivity and pre‐establishment land use.