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Lanzhou University (2009)

Characteristics of Nitrogen Content of Rhizosphere and Xerophilous Shrubs

詹媛媛;

Titre : Characteristics of Nitrogen Content of Rhizosphere and Xerophilous Shrubs

Auteur : 詹媛媛;

Grade : Master’s Theses 2009

Université : Lanzhou University

Résumé
Nitraria tangutorum,Zygophyllum xanthoxylum,Reaumuria soongorica, Ammopiptanthus mongolicu,Atraphaxis bracteata,Haloxylon ammodendron,Ceratoides latens,which widely distributed in the Alashan arid desert area,were selected to study the nitrogen status of various forms,organic carbon content and change of soil pH in rhizosphere and shrubs soil by sampling on field and then analyzing in laboratory.The results showed that contents of soil total nitrogen,ammonium,nitrate and soil organic carbon in rhizosphere soil were 24.9%,24.5%and 65.1%and 18.5%higher than that the bulk soil.Rhizosphere pH was 0.14 units lower than the average of bulk soil.There were significant differences in contents of soil total nitrogen,nitrate and organic carbon content between rhizosphere and bulk soil.The contents of soil total nitrogen,nitrate and organic carbon in the rhizosphere of all the seven shrubs are higher than those in bulk soil. Except of Ammopiptanthus mongolicus,the soil ammonium content in other shrubs’ rhizosphere was higher than bulk soil.Among the seven shrubs,only the pH in Haloxylon ammodendron’s rhizosphere was higher than that of the bulk soil.The differences in soil organic carbon and soil total nitrogen between the rhizosphere and bulk soil showed a significant linear relationship.There was no correlation in soil total nitrogen and ammonium between the rhizosphere and bulk.Soil total nitrogen and nitrate in the rhizosphere and the bulk soil were significantly correlated.The contents of total nitrogen,ammonium,nitrate and soil organic carbon in IC(In the Crown),OC(Out of Crown),MS(Middle of Shrubs) all showed IC>OC>MS.Soil pH showed different trend in seven shrubs:in Nitraria tangutorum,Zygophyllum xanthoxylum,Ammopiptanthus mongolicu,Atraphaxis bracteata and Ceratoides lateens pH showed IC<OC<MS,whereas in Reaumuria soongorica and Haloxylon ammodendron showed the opposite trend,IC>OC>MS.Ammonium and nitrate were significant in three positions,but the difference of pH were not significant.Contents soil oganic carbon in IC and OC did not show significant difference,however,they all had significant difference with MS soil.The total nitrogen content in IC and MS showed significant differences,yet,the differenence between IC and OC,OC and MS were not significant.Concluding from enrichment ratio,IC and OC siol enriched soil nutrient,but EIC/MS>EOC/MS,so enrichment degree of IC were higher than OC,MS siol nutrient was the lowest.Soil pH were negative enrichment ratio,and EIC/MS<EOC/MS showed that soil acidification degree of IC were higher than OC and MS.In vertical Direction,with the depth of 0-10cm,10-20cm and 20-30cm in soil,the contents of soil oganic carbon,total nitrogen and nitrate showed 0-10cm<10-20cm<20-30cm in all seven shrubs ;Except of Reaumuria soongorica,Atraphaxis bracteata and Haloxylon ammodendron,the soil pH showed 0-10cm>10-20cm>20-30cm in the other four shrubs ;Contents of ammonium in Reaumuria soongorica was 0-10cm>10-20cm>20-30cm,and the other six shrubs showed the opposite trend

Mots clés : Arid desert area; Shrubs; Rhizosphere; Shrub soil; Nitrogen;

Présentation (CNKI)

Page publiée le 5 avril 2018