Chinese Journal of Agrometeorology ›› 2012, Vol. 33 ›› Issue (04): 505-511.doi: 10.3969/j.issn.1000-6362.2012.04.006

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Effect of Elevated Ultraviolet-B Radiation on Content of Microbial Biomass C and Soil Respiration in Three Barley Cultivars Field

LOU Yun sheng, GU Xia tian, ZHOU Wen lin, SANG You wei   

  1. 1Jiangsu Key Laboratory of Agricultural Meteorology / College of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing210044,China;2College of Atmospheric Physics,Nanjing University of Information Science and Technology, Nanjing210044
  • Received:2012-03-02 Online:2012-11-20 Published:2013-02-26

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Abstract: Field simulating experiment was conducted to investigate the effects of elevated UV-B radiation on the content of microbial biomass C in rhizosphere and non rhizosphere soils as well as soil respiration in three barley cultivars.The elevated UV-B radiation was treated from tillering stage until maturity stage.Soil microbial biomass C and soil respiration were measured at main growth stages.The experiment was designed with two UV-B radiation levels,i.e. ambient (A,control)and elevated by 120% (E,14.4kJ·m-2·d-1).The tested barley cultivars were Dan 2, Supi 3 and Supi 4.The results indicated that,microbial biomass C in three barley rhizosphere and non rhizosphere soils changed with growth stages and showed the same tendency,i.e. gradually increased from tillering,jointing to booting,and then reached the peak value at heading stage,but significantly decreased at maturity stage,similarly,elevated UV-B radiation had no effect on the above tendency.Compared with control,elevated UV-B radiation significantly reduced microbial biomass C in rhizosphere and non rhizosphere soils in most growth stages of three tested cultivars,but obviously increased microbial biomass C in non rhizosphere soils of cultivar Dan 2 and cultivar Supi 4 at booting stage (P＜0.05).Soil respiration rate was significantly lower under elevated UV-B radiation than that under control at booting and maturity stage of cultivar Dan 2,as well as at heading and maturity stage of cultivar Supi 3,no significant differences existed during other stages.Soil respiration rate gradually increased from tillering,jointing,booting to heading stage,but gradually decreased from heading to maturity stage,regardless of UV-B radiation.Compared to control,elevated UV-B radiation significantly reduced temperature sensitivity coefficients (Q10)of cultivar Dan 2 and cultivar Supi 3,but significantly enhanced Q10 of cultivar Supi 4,which was clearly higher than that of other two cultivars (P＜0.05).It is suggested that the different responses of microbial biomass C and soil respiration to elevated UV-B radiation existed among the three barley cultivars.

Key words: UV-B radiation, Barley, Rhizosphere, Non rhizosphere, Microbial biomass C, Soil respiration, Q10

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