黄土高原典型草原优势植物凋落物分解及养分释放对氮添加的响应

发布时间：2019-07-03 17:10

【摘要】：利用原位分解袋法研究了黄土高原典型草原优势植物长芒草(Stipa bungeana)和阿尔泰狗娃花(Heteropappus altaicus)凋落物的养分释放过程对氮添加的响应,试验周期为1 a。设置6个氮添加水平,分别为N0(0)、N1(1.15 g N m~(-2)a~(-1))、N2(2.3 g N m~(-2)a~(-1))、N3(4.6 g N m~(-2)a~(-1))、N4(9.2 g N m~(-2)a~(-1))和N5(13.8 g N m~(-2)a~(-1)),氮素类型为尿素((NH_2)_2CO)。结果表明:(1)氮添加处理两年显著改变了长芒草和阿尔泰狗娃花凋落物的初始化学性质。随着氮梯度的增加,凋落物的N(氮)含量逐渐增加,木质素含量先增加后下降,C/N(碳氮比)和木质素/N降低,C(碳)、P(磷)和C/P(碳磷比)没有显著的差异。(2)氮处理对长芒草和阿尔泰狗娃花凋落物的分解速率的影响不显著。长芒草和阿尔泰狗娃花凋落物C含量随分解时间整体为降低过程,N和P含量总体上为增加过程,且整个分解过程中N含量各处理间差异显著。(3)氮处理对长芒草和阿尔泰狗娃花凋落物C和P的分解基本无影响,两种元素都呈现释放过程。氮处理对凋落物的N残留率有显著的影响,在N1—N3(1.15—4.6 g/m~2)处理下的长芒草凋落物N残留率高于其他处理,且呈现富集过程;而阿尔泰狗娃花凋落物中的N呈现富集-释放过程。在土壤养分贫瘠的黄土高原典型草原,适量的氮输入可以促进系统的固氮。
[Abstract]:In situ decomposition bag method was used to study the response of nutrient release process to nitrogen addition in the litter of (Stipa bungeana) and (Heteropappus altaicus), a typical grassland plant in the Loess Plateau. The experimental period was 1 a. Six nitrogen addition levels were set as N0 (0), N1 (1.15g N ~ (- 2) a ~ (- 1), N _ 2 (2.3g N ~ (- 2) a ~ (- 1), N _ 3 (4.6g N ~ (- 2) a ~ (- 1), N4 (9.2g N ~ (- 2) a ~ (- 1) and N5 (13.8g N ~ (- 2) a ~ (- 2) a ~ (- 1), nitrogen types were urea (NH_2) _ 2CO). The results showed that: (1) nitrogen addition significantly changed the initial chemical properties of flower litter of Elaeagnus angustifolia and Altaigova in two years. With the increase of nitrogen gradient, the N (nitrogen) content of litter increased gradually, the lignin content increased at first and then decreased, but there was no significant difference between C 鈮，

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