Data from: Soil carbon accumulation differences: allocation of visible plant biomass, carbon and nitrogen in two turfgrasses

Carbon accumulation in turfgrass soils by plant material may be beneficial to CO2 sequestration and soil health, but at high rates can easily lead to declined turfgrass quality (i.e. thatch and mat layer formation). In a field study it was investigated how the fraction of visible plant biomass of turfgrass (sub)species monocultures, with two or three varieties as monoculture per (sub)species, and its C and N concentration and CN ratio in this visible plant biomass in thatch, mat and soil layers contributes to C accumulation. In total three Festuca rubra subspecies; Festcua rubra commutata (Frc), Festuca rubra trichophylla (Frt), Festuca rubra rubra (Frr), and three Agrostis species; Agrostis canina (Acn), Agrostis capillaris (Acp), Agrostis stolonifera (As), were studied. The study was conducted on 3 years old turfgrass demonstration fields of two turfgrass seed companies: Festuca rubra subspecies samples were collected at a site of Barenbrug in Wolfheze (52°00´N, 5°46´E), and Agrostis species were sampled at a site of DLF in Moerstraten (51°32´N, 4°20´E), both in the Netherlands. Both sites were built on a sandy soil. For every variety, cores of the top 20 cm of the soil including aboveground biomass were taken with a core sampler (diameter 28 mm). The core was immediately divided into 4 distinctive layers, thatch + aboveground biomass, mat, remaining upper 10 cm soil and 10-20 cm soil. Distinction of these layers followed the protocol of Evers et al. (2024). Aboveground biomass was separated from the thatch with scissors. Sediment from thatch, mat, remaining upper 10 cm of soil and 10-20 cm soil was carefully washed out with tap water, after which the remaining below-ground (dead and living) visible plant biomass and aboveground biomass was dried at 65 °C until stable weight and weighed. Total C and N analyses were carried out with a Vario Micro Cube Element Analyzer (Elementar, Langenselbold, Germany), from which C and N concentrations (in % of dry matter of plant biomass) and C to N ratios (CN ratio) were calculated.草本草坪土壤中植物残体介导的碳固存，或可助力二氧化碳封存与土壤健康提升，但施加量过高时易导致草坪品质下降，具体表现为枯草层（thatch）和垫层（mat）的形成。本田间试验旨在探究：单播种植的草坪草（亚）种的可见植物生物量占比（每个（亚）种设置2~3个品种作为单播处理），及其在枯草层、垫层与土壤层中可见植物生物量的碳（C）、氮（N）浓度与碳氮比（CN ratio），对碳固存过程的贡献。 本试验共研究了3种紫羊茅（Festuca rubra）亚种：匍匐紫羊茅（Festuca rubra commutata, Frc）、细叶紫羊茅（Festuca rubra trichophylla, Frt）、紫羊茅原亚种（Festuca rubra rubra, Frr），以及3种剪股颖属（Agrostis）植物：绒毛剪股颖（Agrostis canina, Acn）、细弱剪股颖（Agrostis capillaris, Acp）、匍匐剪股颖（Agrostis stolonifera, As）。 试验设于荷兰两家草坪草种业公司的3年生草坪示范田：紫羊茅亚种样品采自位于沃尔赫泽（Wolfheze，52°00′N，5°46′E）的巴伦布格（Barenbrug）基地，剪股颖属植物样品采自位于莫斯特拉滕（Moerstraten，51°32′N，4°20′E）的DLF基地，两处试验田均建于砂质土壤之上。 针对每个品种，采用直径28 mm的土钻采集包含地上生物量的0~20 cm表层土壤柱样。土钻采集完成后立即将柱样划分为4个明确分层：枯草层+地上生物量层、垫层、剩余0~10 cm表层土壤层以及10~20 cm土层。分层方法遵循Evers等人（2024）的试验规程。使用剪刀将地上生物量与枯草层分离。随后用自来水轻柔冲洗枯草层、垫层、0~10 cm剩余表层土壤及10~20 cm土层中的沉积物，将残留的地下（活体与枯死）可见植物生物量及地上生物量置于65 ℃下烘干至恒重后称重。采用Vario Micro Cube元素分析仪（德国Elementar公司，朗塞恩博尔登）开展总碳、总氮测定，并据此计算植物生物量干物质中的碳、氮浓度（以百分比计）及碳氮比（CN比）。