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试验设对照(CK,0 kg.hm-2.a-1)、低氮(LN,50 kg.hm-2.a-1)、中氮(MN,150kg.hm-2.a-1)和高氮(HN,300 kg.hm-2.a-1)4个施氮水平,通过原位试验,研究了模拟N沉降对华西雨屏区慈竹(Neosinocalamus affinis)林凋落物分解的影响.结果表明:不同组分凋落物分解过程中,慈竹叶片分解速率最快,其次是箨,枝最慢,分解15个月时,叶片、箨、枝的质量残留率分别为26.38%、46.18%和54.54%,三者差异极显著(P<0.01);叶片在凋落后第1~2月和7~10月分解较快,而箨和枝则在第5~8月分解较快;凋落叶片分解95%需要的时间(2.573年)分别比箨和枝短1.686年和3.319年.凋落叶分解15个月时,各N沉降处理间分解率差异不显著;凋落箨分解95%需要2.679~4.259年,其中MN分解率最高,CK最低;凋落枝经过15个月的分解,各处理分解率大小顺序为MN>HN>LN>CK,MN与LN处理间差异达显著水平(P<0.05).说明N沉降对3种凋落物分解均有明显的促进作用,且对凋落箨促进作用最强;但随着N沉降浓度的增加和时间的延长,其促进作用减缓.
The experimental control (CK, 0 kg.hm-2.a-1), low nitrogen (LN, 50 kg.hm-2.a-1) And high nitrogen (HN, 300 kg · hm-2.a-1). The effects of simulated N deposition on litter decomposition in Neosinocalamus affinis forest in the Huaxi rainfed area were studied through in situ experiments The results showed that during the process of litter decomposition, the leaf decomposition rate of Phyllostachys edulis was the fastest, followed by 箨 and twig branches, the mass residual rates of leaves, 箨 and branches were 26.38% and 46.18 % And 54.54%, respectively, with significant difference (P <0.01). The leaves were rapidly decomposed from January to February and from July to October after litterfall, The time required to decompose 95% (2.573 years) was 1.686 and 3.319 years respectively than that of S. japonicum and S. japonicum. When the litter decomposition was 15 months, there was no significant difference in the decomposition rate between N treatments. The decomposition rate of 95% , With the highest decomposition rate of MN and the lowest of CK. After 15 months of decomposition, the order of decomposition rate of each treatment was MN> HN> LN> CK, and the difference between MN and LN was significant (P <0.05). N deposition significantly promoted the litter decomposition of three kinds of litter and promoted the littering Strongest; but with the increasing settling time and the N concentration, which promote slow.