發(fā)布時間：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)勢植物長芒草(Stipa bungeana)和阿爾泰狗娃花(Heteropappus altaicus)凋落物的養(yǎng)分釋放過程對氮添加的響應(yīng),試驗(yàn)周期為1 a。設(shè)置6個氮添加水平,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)氮處理對長芒草和阿爾泰狗娃花凋落物的分解速率的影響不顯著。長芒草和阿爾泰狗娃花凋落物C含量隨分解時間整體為降低過程,N和P含量總體上為增加過程,且整個分解過程中N含量各處理間差異顯著。(3)氮處理對長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，

本文編號：2509545