污泥对干旱条件下高羊茅氮素利用的影响
Impact of biosolids on nitrogen use in drought-stressed tall fescue
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摘要: 在相同氮肥条件下,研究了污泥对干旱条件下高羊茅氮素利用的影响。采用裂区试验设计,主处理包括正常 浇水和干旱2 个水平;副处理为不同的氮源:对照(75 mg/kg 的氮素由硝酸铵提供)、半污泥(硝酸铵和污泥各提供 37.5 mg/kg 的氮素)、全污泥(75 mg/kg 的氮素由污泥提供)。结果表明:全污泥和半污泥处理能够显著提高正常浇 水和干旱胁迫下高羊茅的坪观质量,增加高羊茅的地上生物量和根系干质量(P 0.05);并提高正常浇水和干旱胁 迫下高羊茅叶片的硝酸还原酶活性和重度干旱(20%田间持水量)下的根系硝酸还原酶活性(P 0.05);不同氮源 处理在2 种水分条件下的根系和叶片的全氮含量及氮产出量差异显著(P 0.05)。说明施用污泥能够促进干旱条 件下高羊茅的氮素利用。Abstract: This study investigates biosolids' impact on nitrogen(N) use in tall fescue(Festuca arundinacea) under same nitrogen level and drought stress conditions. A split-plot design was used with soil moisture regimes ( well-watered and drought stress) as main plots and biosolid treatments as subplots. The biosolids treatments included: 1) control (75 mg/kg N completely provided by NH4 NO3 solution); 2) half-biosolids (37.5 mg/kg N provided by biosolids, and 37.5 mg/kg N provided by NH4NO3 solution); 3) whole-biosolids (75 mg/kg N completely provided by biosolids). Whole-biosolids and half-biosolids improved turfgrass quality, increased clippings and root dry weight of tall fescue under well-watered and drought stress conditions (P 0.05). Biosolids treatments also increased leaf nitrate reductase activity under both soil moisture regimes , and root nitrate reductase under severe drought stress (20% container capacity) (P 0.05). Significant differences in leaf and root TKN as well as N output were observed among biosolids treatments (P 0.05). Our data suggest that biosolids application may improve drought tolerance and promote N use of tall fescue under drought stress.