Shuster William D, Shipitalo Martin J, Subler Scott, Aref Susanne, McCoy Edward L, McKeegan Christina
School of Natural Resources, The Ohio State University, OARDC, Wooster, OH 44691, USA.
J Environ Qual. 2003 Nov-Dec;32(6):2132-9. doi: 10.2134/jeq2003.2132.
Earthworms affect soil structure and the movement of agrochemicals. Yet, there have been few field-scale studies that quantify the effect of earthworms on dissolved nitrogen fluxes in agroecosystems. We investigated the influence of semi-annual earthworm additions on leachate production and quality in different row crop agroecosystems. Chisel-till corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation (CT) and ridge-till corn-soybean-wheat (Triticum aestivum L.) rotation (RT) plots were arranged in a complete randomized block design (n = 3) with earthworm treatments (addition and ambient) as subplots where zero-tension lysimeters were placed 45 cm below ground. We assessed earthworm populations semi-annually and collected leachate biweekly over a three-year period and determined leachate volume and concentrations of total inorganic nitrogen (TIN) and dissolved organic nitrogen (DON). Abundance of deep-burrowing earthworms was increased in addition treatments over ambient and for both agroecosystems. Leachate loss was similar among agroecosystems, but earthworm additions increased leachate production in the range of 4.5 to 45.2% above ambient in CT cropping. Although leachate TIN and DON concentrations were generally similar between agroecosystems or earthworm treatments, transport of TIN was significantly increased in addition treatments over ambient in CT cropping due to increased leachate volume. Losses of total nitrogen in leachate loadings were up to approximately 10% of agroecosystem N inputs. The coincidence of (i) soluble N production and availability and (ii) preferential leaching pathways formed by deep-burrowing earthworms thereby increased N losses from the CT agroecosystem at the 45-cm depth. Processing of N compounds and transport in soil water from RT cropping were more affected by management phase and largely independent of earthworm activity.
蚯蚓会影响土壤结构和农用化学品的移动。然而，很少有田间尺度的研究对蚯蚓对农业生态系统中溶解态氮通量的影响进行量化。我们研究了半年一次添加蚯蚓对不同行栽作物农业生态系统中渗滤液产生及质量的影响。凿耕玉米（Zea mays L.）-大豆[Glycine max (L.) Merr.]轮作（CT）和垄耕玉米-大豆-小麦（Triticum aestivum L.）轮作（RT）小区采用完全随机区组设计（n = 3），以蚯蚓处理（添加和对照）作为子小区，在地下45厘米处放置零张力渗滤计。我们每半年评估一次蚯蚓数量，并在三年时间里每两周收集一次渗滤液，测定渗滤液体积以及总无机氮（TIN）和溶解有机氮（DON）的浓度。与对照相比，添加处理增加了两个农业生态系统中深穴居蚯蚓的数量。不同农业生态系统间渗滤液损失情况相似，但在CT种植中，添加蚯蚓使渗滤液产量比对照增加了4.5%至45.2%。尽管不同农业生态系统或蚯蚓处理之间渗滤液TIN和DON浓度通常相似，但由于渗滤液体积增加，CT种植的添加处理中TIN的迁移量比对照显著增加。渗滤液负荷中总氮损失高达农业生态系统氮输入的约10%。（一）可溶性氮的产生和有效性与（二）深穴居蚯蚓形成的优先淋溶路径的重合，从而增加了CT农业生态系统在45厘米深度处的氮损失。RT种植中氮化合物的处理和土壤水中的迁移受管理阶段的影响更大，且在很大程度上与蚯蚓活动无关。
