Agroecosystem resilience in response to extreme winter flooding
Agroecosystem resilience in response to extreme winter flooding
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DOI：
10.1016/j.agee.2019.04.001
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发表时间：
2019-07-01
影响因子：
6.6
通讯作者：
Jones, Davey L.
中科院分区：
文献类型：
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作者：
Harvey, Rachel J.;Chadwick, David R.;Jones, Davey L.
有证据表明，气候变化正在增加极端天气事件（如过度降雨、高温、大风）的频率。2013年至2014年冬季，英国各地降雨量异常，导致几个低洼农业区（如萨默塞特高地、泰晤士河谷）发生了极端且持续时间长的洪水（长达3个月，洪水深度达3米）。然而，人们对极端洪水的影响和野外生态系统恢复的速度仍然知之甚少。因此，这项研究的主要目标是：(1)评估这个冬季极端洪水事件的影响在一系列土壤物理、化学和生物质量指标15受灾地点(耕地和草地),(2)确定土壤健康的变化是可逆的在短期内(< 1年),(3)来评估不同的机械干预措施的有效性(sward-lifting,深耕,slot-seeding和曝气)加快改善冬季洪水造成的损害在2的15个网站。一旦洪水退去（2014年4月），我们发现与非洪水地区相比，洪水地区的土壤质量指标受到了负面影响。这包括土壤容重（下降19%），土壤pH（下降0.4个单位）和有效磷（下降42%）。洪水增加了土壤微生物生物量（60%），引起了土壤微生物群落结构的变化和蚯蚓数量的减少。恢复8个月后，只有淹水地区的土壤pH值与未淹水地区相比仍显著降低（降低0.3个单位）。洪水对耕地上覆植被产生了负面影响（生物量产量减少了19% ~ 34%），但对草地上覆植被的长期影响不大。在洪水改良试验中，深土地块生产的草具有较高的营养含量（如N -高达35%，Ca -高达19%，Mg -高达58%）。然而，这四种不同的干预措施对测量的大多数土壤质量指标似乎没有什么积极影响。综上所述，极端冬季洪水会导致关键土壤质量指标的短期变化，并破坏冬季作物，但这些影响不会长期持续。因此，我们的研究结果表明，这里评估的温带农业生态系统对冬季洪水胁迫具有高度的弹性，并且可以在1年内恢复到洪水前的状态。仍然需要改进管理战略，以加快洪水事件后的恢复速度，促进更快地恢复农业生产。
Evidence suggests that climate change is increasing the frequency of extreme weather events (e.g. excessive rainfall, heat, wind). The winter of 2013-14 saw exceptional levels of rainfall across the UK leading to extreme and prolonged flooding (up to 3 months with floodwater depths up to 3 m) in several low-lying agricultural areas (e.g. Somerset Levels, Thames Valley). The impact of extreme flooding and the speed of ecosystem recovery at the field-scale, however, remain poorly understood. The main objectives of this study were therefore to: (1) assess the effect of this extreme winter flooding event on a range of soil physical, chemical and biological quality indicators at 15 flood-affected sites (arable and grassland), (2) determine if these changes in soil health were reversible in the short term ( < 1 year), and (3) to evaluate the effectiveness of different mechanical interventions (sward-lifting, subsoiling, slot-seeding and aerating) to accelerate the amelioration of the damage caused by winter flooding at 2 of the 15 sites. Once the floodwater had receded (April 2014), we found that several of the measured soil quality indicators were negatively affected in the flooded areas in comparison with non flooded areas. This included a decrease in soil bulk density (by 19%), soil pH (by 0.4 units), and available P (by up to 42%). Flooding increased soil microbial biomass (60%), induced a shift in soil microbial community structure and reduced earthworm numbers. After 8 months of recovery, only soil pH remained significantly reduced (by 0.3 units) in the flooded areas in comparison to the unflooded areas. Flooding had a negative impact on the overlying vegetation at the arable sites (biomass production was reduced by between 19 and 34%) but had no major impact at the grassland sites in the long-term. In the flood amelioration experiment, the subsoiled plots produced grass with a higher nutrient content (e.g. N - up to 35%, Ca - up to 19% and Mg - up to 58%). However, the four different interventions appeared to have little positive impact on most of the soil quality indicators measured. In conclusion, extreme winter flooding was found to induce short-term alterations in key soil quality indicators and to destroy winter crops, although these effects did not persist in the longer term. Our results therefore indicate that the temperate agroecosystems evaluated here were highly resilient to winter flood stress and that recovery to a pre-flood state could be achieved within 1 year. Improved management strategies are still needed to speed up the rate of recovery after flood events to facilitate a faster return to agricultural production.