Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Ceredigion, Wales SY23 3EE, UK.
Sci Total Environ. 2024 Nov 15;951:175598. doi: 10.1016/j.scitotenv.2024.175598. Epub 2024 Aug 17.
Grasslands globally deliver many ecosystem services, including water management to alleviate flood risk reduction. Two replicated field experiments were conducted to study how agricultural forage species with diverse rooting systems, sown as single species, affected rooting, soil structure and earthworm populations, and consequently water infiltration to understand how they each might influence flood risk from grasslands. Experiment One showed soils under red clover (Trifolium pratense), white clover (Trifolium repens) and chicory (Cichorium intybus) had higher infiltration rates three years after establishment, compared to perennial ryegrass (Lolium perenne). Higher red clover and chicory root biomass or increased earthworm abundance under white clover may have caused these effects. Experiment Two monitored infiltration at intervals over several years post establishment to understand the timeframe for changes in rates; plantain (Plantago lanceolata) was sown as an additional forage. Infiltration declined post establishment, the timing and extent of decline varying with forages; forage effects were significant after 27 months (P < 0.05). Infiltration rates were higher under red and white clover compared to ryegrass, with chicory and plantain intermediate (P < 0.05). Forages again differed in likely mechanisms delivering higher water infiltration, notably between the two clover species. White clover had higher earthworm biomass (P < 0.05), whereas red clover had a higher average root diameter compared to the other forages (P < 0.05). Drivers of intermediate benefits of chicory and plantain also differed: chicory had higher earthworm abundance (month 38) compared to plantain, which had higher average root diameter compared to ryegrass (month 41); 30 months post-establishment soil bulk density was lower under both forages compared to ryegrass and red clover, with white clover intermediate (P < 0.05); bulk density and penetration resistance did not relate to infiltration. Findings demonstrate that a shift from perennial ryegrass-dominated pastures to swards with more contrasting forages provides an ecohydrological approach to mitigating flood risk and climate adaptation.
全球草原提供了许多生态系统服务，包括管理水资源以减轻洪水风险。进行了两项复制的田间实验，以研究具有不同根系系统的农业饲料物种如何作为单一物种播种，从而影响根系、土壤结构和蚯蚓种群，并因此了解它们如何影响草原的洪水风险。实验一表明，与多年生黑麦草（Lolium perenne）相比，在建立后的三年中，红三叶草（Trifolium pratense）、白三叶草（Trifolium repens）和菊苣（Cichorium intybus）下的土壤具有更高的入渗率。较高的红三叶草和菊苣根系生物量或白三叶草下蚯蚓丰度的增加可能导致了这些影响。实验二监测了建立后多年的几次入渗间隔，以了解速率变化的时间范围；车前草（Plantago lanceolata）被播种为额外的饲料。建立后，入渗率下降，下降的时间和程度因饲料而异；27 个月后（P<0.05），饲料的影响显著。与黑麦草相比，红三叶草和白三叶草下的入渗率较高，而菊苣和车前草居中（P<0.05）。饲料在提供更高的水分入渗方面再次表现出不同的机制，特别是在两种三叶草之间。白三叶草的蚯蚓生物量较高（P<0.05），而红三叶草的平均根直径与其他饲料相比更高（P<0.05）。菊苣和车前草中间效益的驱动因素也不同：与车前草相比，菊苣的蚯蚓丰度较高（第 38 个月），而与黑麦草相比，车前草的平均根直径较高（第 41 个月）；建立后 30 个月，两种饲料下的土壤容重均低于黑麦草和红三叶草，而白三叶草居中（P<0.05）；容重和穿透阻力与入渗无关。研究结果表明，从以多年生黑麦草为主的牧场向具有更多对比饲料的草丛转变，为减轻洪水风险和适应气候变化提供了一种生态水文学方法。
