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Accueil du site → Doctorat → Chine → 2008 → Effects of the Different Grazing Systems on Vegetation and Soil of Stipa Breviflora Desert Steppe

Inner Mongolia Agricultural University (2008)

Effects of the Different Grazing Systems on Vegetation and Soil of Stipa Breviflora Desert Steppe

闫瑞瑞; Zuo Rui Rui

Titre : Effects of the Different Grazing Systems on Vegetation and Soil of Stipa Breviflora Desert Steppe

Auteur : 闫瑞瑞; Zuo Rui Rui

Grade : Doctoral Dissertation 2008

Université : Inner Mongolia Agricultural University

Résumé partiel
Effects of rotational and continuous grazing on plant population,community and soil characteristics of Stipa breviflora desert steppe were investigated during 2005-2007 year.The main results were shown as follows:1 Grazing decreased the height of Stipa breviflora and Cleistogenes songorica ;the coverage,the density,the importance value of Cleistogenes songorica and Allium polyrhizum in rotational grazing were higher than those in continuous grazing,which of Stipa breviflora in continuous grazing were higher than those in rotational grazing.Banning and rotational grazing were beneficial to increase the above-ground standing crop and the relative standing crop of Cleistogenes songorica and Allium polyrhizum.Continuous grazing was beneficial to increase the above-ground standing crop and the relative standing crop of Stipa breviflora.2 Banning and rotational grazing improved plant growth and sexual reproduction ; Rotational grazing increased tiller nodes biomass of Allium polyrhizum,energy of standing crop and total standing crop of population modulus of Stipa breviflora and Allium polyrhizum.The root biomass,energy of standing crop and the ratio of their allocation,and ratio of root to crown of the main plant populations in the two grazing systems were higher than those in ungrazed pasture.The calorific value of different modulus among major plant population and whole plants in rotational grazing were higher than that in continuous grazing.There were no significant trade-off between vegetative and reproductive shoot biomass/energy,but trade-off between tiller nodes and vegetative shoot biomass/energy was observed.3 The double-peaks on the curves of diurnal changes of photosynthetic rates, transpiration rates and stomatal conductance of Stipa breviflora,Cleistogenes songorica and Allium polyrhizum were observed,and there was distinct phenomenon of“noon break”.The double-valley on the curves of diurnal changes of internal CO2 concentration was observed.Rotational grazing increased the photosynthetic rates,transpiration rates,stomatal conductance and internal CO2 concentration of the major plant populations on desert steppe.Photosynthetic response of Stipa breviflora,Cleistogenes songorica and Allium polyrhizum to Photosynthetically active Radiation(PAR) in the different treatment were“parabola”type.Photosynthetic response curves of the same plant to PAR were that banning grazing area was higher than rotational grazing area,in turn,higher than continuous grazing area.There were significant positive correlation between the photosynthesis rates,transpiration rate and stomatal conductance and PAR of the main plant populations under the different treatments.The trend of internal CO2 concentration was slightly decreasing with the increase of PAR,which was quadratic polynomial equation expressed on PAR.4 The trends of density and coverage of Stipa breviflora were decrease,and the rate of decline in rotational grazing was light.The trends of density of Cleistogenes songorica and Allium polyrhizum were increase in rotational and banning grazing area

Mots clés : Grazing system; Desert steppe; Plant charaeteristics; soil physical and chemical properties;

Présentation (CNKI)

Page publiée le 1er mai 2013, mise à jour le 9 janvier 2018