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

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。

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.