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Inner Mongolia Agricultural University (2020)

Effects of Grazing on Phosphorus Balance in A Typical Steppe of Inner Mongolia

乌力吉

Titre : Effects of Grazing on Phosphorus Balance in A Typical Steppe of Inner Mongolia

Auteur : 乌力吉;

Grade : Doctoral Dissertation 2020

Université : Inner Mongolia Agricultural University

Résumé partiel
Livestock grazing is the most important and direct way to use grassland ecosystems.Grazing intensity(GI)is a key factor for nutrient input and output of grassland ecosystems.Phosphorus(P)is an essential element for plant growth and reproduction involving in the physiological and biochemical processes of organisms in many forms.Most studies focus on the carbon and nitrogen cycling,however,the process and mechanism of P balance remain understudied,especially for effects of grazing on P balance in grassland ecosystems.This study was carried out at long term grazing experiment in Inner Mongolia Grassland Ecosystem Research Station the Chinese Academy of Science.This study carried out in a randomized block design with 2 topography and 7 grazing intensities,including 14 grazing treatments in total.P concentration,P pool and P turnover of different grassland components were studied for 2 years.Main results as follows :(1)At the depth of 0-20cm,grazing had significant effects on soil total P concentration and P pool,and topography was also the main factor affecting the soil total P concentration and P pool.Soil total P concentration and P pool decreased(P<0.05)with an increase in GI in the flat grazing system,whereas they increased(P<0.05)slightly with an increase in GI in the slope grazing system.Soil total P concentration and P pool were higher(P<0.001)in the flat than in the slope.GI had no effects on the spatial heterogeneous of soil total P concentration,whereas the effects of spatial heterogeneous was greater than grazing treatment.The spatial heterogeneous of the flat grazing system was greater than the slope.GI and topography had significant effects on soil available-P(P<0.05),it increased with GI in two years.Soil available-P was higher(P<0.001)in the flat than in the slope.(2)Grazing had little effect on P concentration of the plant community(P>0.05),but the aboveground biomass P pool was influenced(P<0.001),and the differences was due to the different contribution of biomass.The aboveground biomass P concentration and P pool were also impacted by the year and topography(P<0.001)

Mots clés : typical grassland; grazing intensity; P cycling; P concent rationt; P pool; topography;

Présentation (CNKI)

Page publiée le 3 juin 2021, mise à jour le 22 octobre 2021