發(fā)布時(shí)間：2019-07-03 17:10

【摘要】：利用原位分解袋法研究了黃土高原典型草原優(yōu)勢(shì)植物長(zhǎng)芒草(Stipa bungeana)和阿爾泰狗娃花(Heteropappus altaicus)凋落物的養(yǎng)分釋放過程對(duì)氮添加的響應(yīng),試驗(yàn)周期為1 a。設(shè)置6個(gè)氮添加水平,分別為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)),氮素類型為尿素((NH_2)_2CO)。結(jié)果表明:(1)氮添加處理兩年顯著改變了長(zhǎng)芒草和阿爾泰狗娃花凋落物的初始化學(xué)性質(zhì)。隨著氮梯度的增加,凋落物的N(氮)含量逐漸增加,木質(zhì)素含量先增加后下降,C/N(碳氮比)和木質(zhì)素/N降低,C(碳)、P(磷)和C/P(碳磷比)沒有顯著的差異。(2)氮處理對(duì)長(zhǎng)芒草和阿爾泰狗娃花凋落物的分解速率的影響不顯著。長(zhǎng)芒草和阿爾泰狗娃花凋落物C含量隨分解時(shí)間整體為降低過程,N和P含量總體上為增加過程,且整個(gè)分解過程中N含量各處理間差異顯著。(3)氮處理對(duì)長(zhǎng)芒草和阿爾泰狗娃花凋落物C和P的分解基本無影響,兩種元素都呈現(xiàn)釋放過程。氮處理對(duì)凋落物的N殘留率有顯著的影響,在N1—N3(1.15—4.6 g/m~2)處理下的長(zhǎng)芒草凋落物N殘留率高于其他處理,且呈現(xiàn)富集過程;而阿爾泰狗娃花凋落物中的N呈現(xiàn)富集-釋放過程。在土壤養(yǎng)分貧瘠的黃土高原典型草原,適量的氮輸入可以促進(jìn)系統(tǒng)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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