| Wetland is an important part of the ecological system in arid area,with global climate change,wetlands water changes by glaciers supplied will have a profound effect on the balance of carbon and nitrogen in the process of maintain wetland structure,function and geochemical cycle.Moreover,water content changes had a influence on the vegetation types.To compare the difference between C,N and P of live plant-litter-soil under different water conditions,total carbon(TC),total nitrogen(TN)and total phosphorus(TP)of live plant-litter-soil were studied by selecting typical water content zone(A,B,C)at Swan Lake of Bayinbuluke in the middle Tianshan Moutain for my thesis research.Results will provide the basic datas for the stability of the wetland ecosystem in the Alpine,and provide scientific basis for sustainable utilization of wetlands.The main results and conclusions are as follows:(1)Under three water contents,different plants had a different utilizations on carbon,nitrogen and phosphorus.Plant total carbon,total nitrogen content of plant were higher than that of litter.Carbon and nitrogen content of litter increased gradually with the decreasing of water content,the variation trend of N/P was consistent with the content of carbon,nitrogen and phosphorus,but the C/N trend of litter was contrary to the trend of carbon and nitrogen content.(2)Under the three water contents,Carex was in common,its total carbon and N/P decreased with the increase of water content;total nitrogen,total phosphorus,C/N,C/P of Carex were not coordinated with the change of water,and the total nitrogen content were the highest under C water content;total phosphorus content were highest under A water content;C/N,C/P were the highest under B water content;B,C water content of C/N was significantly different(P<0.01);The C/P of the A water content was significantly different with that of B,C water content(P<0.01);There was no significant difference of N/P in three kinds of water(P>0.05).(3)Under the three water conditions,the total carbon,C/N,C/P of other common plants were B>C,indicating that the plants total carbon,C/N and C/P decreased with the decrease of water contentreduced.The total nitrogen,total phosphorus,C/P of other common plants were B<C,i.e.the plant total nitrogen,total phosphorus,C/P increased with the decrease of water contentreduced,and total carbon,total phosphorus,C/P and Orostachys fimbriatus C/N of Limonium sinense were significantly different under B,C water conten(P<0.01).(4)The litter total carbon,total nitrogen,total phosphorus increased with the decrease of water contentreduced,all of these show as C>B.Under the B and C water conditions,the rank for C/N、C/P of litter was B>C,only the N/P of litter was C>B;C/N were significantly different(P<0.01)under B,C water content,but there were no significant difference between C/P and N/P(P>0.05).(5)The rank for character of total carbon,total carbon and total phosphoruscontent in soil were:B > A > C,B > A > C and C>B>A,respectively.With the increase of soil depth,total carbon,total nitrogen and total phosphorus content were gradually reduced.The change of soil C/N was consistent with the change of total phosphorus content;soil C/P and N/P were consistent with total soil carbon and total nitrogen.The content of total carbon and total nitrogen in 30 cm soil was significantly different(P<0.05)under the three water conditions,soil total phosphorus content was significantly different(P<0.05)in 30 cm soil.,C/N,C/P and N/P of the C water content were significantly different with that of B,C water content(P<0.05).(6)There was a negative relationship between the relative soil water and plant,litter carbon,nitrogen,phosphorus content,but water content had a highly significant positive correlation with soil carbon,nitrogen,phosphorus and plant C/N ratio(P<0.01),and it had a negative correlation with plant C/P,plant N/P(P<0.05),litter N/P,soil C/N(P<0.05),also had a positive correlation with litter C/N(P<0.05),litter C/P,soil C/P(P<0.01),soil N/P(P<0.01). |
PDF Full Text Request