国产bbaaaaa片,成年美女黄网站色视频免费,成年黄大片,а天堂中文最新一区二区三区,成人精品视频一区二区三区尤物

首頁> 外文學位 >Impacts of Fine-roots on Terrestrial Net Primary Productivity and Soil Nutrient Cycling.
【24h】

Impacts of Fine-roots on Terrestrial Net Primary Productivity and Soil Nutrient Cycling.

機譯：細根對陸地凈初級生產(chǎn)力和土壤養(yǎng)分循環(huán)的影響。

獲取原文
獲取原文并翻譯 | 示例
  • 摘要
  • 著錄項
  • 相似文獻
  • 相關(guān)主題

摘要

Large uncertainties remain in fine-root longevity, and contribution to terrestrial nutrient cyling. In my dissertation, I utilized a carbon isotope tracer at a long-term Free-Air CO2 Enrichment (FACE) experiment in a Liquidambar styraciflua plantation to examine properties of fine-roots including longevity and sources of carbon for growth and respiration. Soil cores were sequentially sampled for multiple growing seasons following cessation of CO2 fumigation. Fine-roots were extracted from soil and separated by diameter. Newly produced roots were produced from exclusively new photosynthate. Fine-root carbon was replaced more slowly, with about half of the carbon remaining after two full growing seasons. Model fitting found at least two turnover rates for carbon occur in the fine-root population, with 10% of carbon quickly being turned over ( 2 years). In a follow-up study, I utilized a potentially more functional approach by separating roots by root branching order. Results indicate that branching order and root nitrogen concentration correlate with root longevity. Thus, easily measurable traits such as nitrogen concentration may help elucidate root longevity in different species or at larger spatial scales. Knowledge of the longevity and standing biomass of fine-roots is essential for quantifying fine-root contribution to terrestrial NPP and forest nutrient cycling. An extensive literature review was conducted to examine fine-root biomass within branching orders, with just 10 reports in the literature. Even with this sparse data-set, it is clear that environmental conditions such as nutrient and water availability impact fine-root biomass distribution. Increased studies quantifying the amount of biomass in roots by branching order will be needed to fully calculate fine-root contribution to terrestrial carbon and nutrient cycling. A final contribution from my thesis is the creation of a dynamic vegetation model that optimizes both above- and below-ground biomass allocation with respect to changing environmental conditions. Results from empirical research, including that done in my other chapters, conclude that biomass allocation is plastic with respect to abiotic conditions. No current simple modeling scheme adequately captures this plasticity. It is hoped that the model developed here can make progress towards that goal.
機譯：細根壽命和對陸地營養(yǎng)循環(huán)的貢獻仍然存在很大的不確定性。在我的論文中，我在楓香人工林的一項長期自由空氣CO2富集（FACE）實驗中使用了一種碳同位素示蹤劑，以研究細根的特性，包括壽命和碳源的生長和呼吸作用。在停止CO2熏蒸后，對土壤核心進行了多個生長季節(jié)的采樣。從土壤中提取細根并按直徑分離。新產(chǎn)生的根由完全新的光合產(chǎn)物產(chǎn)生。細根碳的置換速度較慢，在兩個完整的生長季節(jié)后，約有一半的碳殘留。模型擬合發(fā)現(xiàn)，細根種群至少有兩種碳轉(zhuǎn)換率，其中有10％的碳迅速被移交（2年）。在后續(xù)研究中，我通過根分支順序?qū)⒏珠_，從而利用了功能更強大的方法。結(jié)果表明，分支順序和根系氮濃度與根系壽命相關(guān)。因此，容易測量的性狀，例如氮濃度，可以幫助闡明不同物種或更大空間尺度上的根壽命。了解細根的壽命和生物量對于量化細根對陸地NPP和森林養(yǎng)分循環(huán)的貢獻至關(guān)重要。進行了廣泛的文獻綜述，以檢查分支順序內(nèi)的細根生物量，文獻中僅有10篇報告。即使使用這種稀疏的數(shù)據(jù)集，很明顯，諸如養(yǎng)分和水的可利用性等環(huán)境條件也會影響根系生物量的精細分布。需要更多的研究來按分支順序?qū)Ω猩锪康臄?shù)量進行量化，以充分計算出細根對陸地碳和養(yǎng)分循環(huán)的貢獻。我的論文的最后貢獻是創(chuàng)建了一個動態(tài)植被模型，該模型可以根據(jù)環(huán)境條件的變化優(yōu)化地上和地下生物量的分配。實證研究的結(jié)果（包括我其他章節(jié)中所做的研究）得出的結(jié)論是，就非生物條件而言，生物量分配具有可塑性。當前沒有任何簡單的建模方案可以充分捕捉這種可塑性。希望這里開發(fā)的模型可以朝著這個目標取得進展。

著錄項

  • 作者

    Lynch, Douglas J.;

  • 作者單位

    University of Illinois at Chicago.;

  • 授予單位 University of Illinois at Chicago.;
  • 學科 Ecology.;Physiology.
  • 學位 Ph.D.
  • 年度 2015
  • 頁碼 149 p.
  • 總頁數(shù) 149
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 遙感技術(shù);
  • 關(guān)鍵詞

相似文獻

  • 外文文獻
  • 中文文獻
  • 專利
獲取原文

客服郵箱：kefu@zhangqiaokeyan.com

京公網(wǎng)安備：11010802029741號 ICP備案號：京ICP備15016152號-6 六維聯(lián)合信息科技 (北京) 有限公司?版權(quán)所有

  • 客服微信

  • 服務(wù)號