氮磷添加对不同退耕年限草本植被群落及土壤化学计量特征的影响

Effects of Nitrogen and Phosphorus Addition on Community and Soil Stoichiometric Characteristics of Abandoned Farmlands of Different Vegetation Restoration Years

采用空间代替时间的方法,根据安塞县纸坊沟小流域8个退耕年限序列(1~35年)的退耕地采样数据进行分析,研究植物群落与土壤化学计量学特征对不同施肥处理的响应程度。结果表明:(1)与未施肥相比,施N肥和施N肥+P肥后,地上生物量分别增加了77.1%和142.0%。地上生物量对不同施肥处理的响应程度表现为施N肥+P肥组合高于单一添加N肥。(2)与未施肥相比,施N肥后叶片氮、磷含量分别增加了13.6%和0.6%,氮磷比下降了3.8%;施N肥+P肥后叶片氮、磷含量分别增加了15.6%和8.7%,氮磷比下降了15.2%,叶片N、P含量及氮磷比对施N肥+P肥的响应程度均高于单一施N肥。(3)与未施肥相比,施N肥后土壤N、P含量分别增加了27.7%和36.2%,N/P比下降了9.1%;施N肥+P肥后土壤N、P含量分别增加了16.6%和25.0%,N/P比下降了9.1%,土壤N、P含量对施N肥的响应程度略高于施N肥+P肥。总体而言,适当的施肥方式有利于植物对土壤养分的利用和分配。

Using comparative analysis and substituting temporal serial with spatial serial data, we analyzed data collected from abandoned farmlands with eight different vegetation restoration years （1 to 35 years）. The responses of plant community and soil stoichiometry to different fertilization treatments were studied. The results were as follows. （1） Compared with the no fertilization treatment, the aboveground biomass was increased by 77. 1% and 142. 0% by the ＋ N and ＋ N＋P treatment, respectively. The response of aboveground biomass to the ＋N＋P treatment was more significant than to the ＋iN treatment. Compared with the no fertilization treatment, leaf N and P concentration was increased by 13.6% and 0. 6 %, while the N/P ratio was reduced by 3.8% by the ＋N treatment. Leaf N and P concentration was increased by 15.6% and 8.7%, while the N/P ratio was reduced by 15.2% by the ＋N＋P treatment. The responses of leaf N and P concentration, and N/P ratio to the ＋ N＋ P treatment were all more significant than to the ＋ N treatment. Compared with the no fertilization treatment, soil N and P content was increased by 27.7% and 36.2%, respectively, and N/P ratio was reduced by 9.1% by the ＋N treatment. Soil N and P content was increased by 16. 6% and 25.0%, respectively, and NIP ratio was reduced by 9.1% by the ＋N＋P treatment. The responses of soil N and P content to the ＋ N treatment were more significant than to the ＋ N＋ P treatment. In conclusion, a proper fertilization mode is beneficial to the utilization and distribution of soil nutrients.