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基于县域单元的陕西日光温室蔬菜冻害风险特征及加温类型 被引量:7
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作者 李美荣 李化龙 +1 位作者 柏秦凤 刘映宁 《中国农学通报》 CSCD 北大核心 2010年第23期318-324,共7页
低温冻害是陕西省干旱半干旱地区设施蔬菜越冬期的主要气象灾害,定量化确定冻害风险,明确加温类型对大棚设计具有重要意义。文章归纳陕北和关中地区不同级别冻害指标,以县为单元提出了分析、计算设施蔬菜越冬期月尺度平均冻害风险定量方... 低温冻害是陕西省干旱半干旱地区设施蔬菜越冬期的主要气象灾害,定量化确定冻害风险,明确加温类型对大棚设计具有重要意义。文章归纳陕北和关中地区不同级别冻害指标,以县为单元提出了分析、计算设施蔬菜越冬期月尺度平均冻害风险定量方法,分析研究区域共68个县(区)冬季各月份多年平均冻害风险时间特征。结果表明:各地冻害频次轻度高于中度、重度,1、12、2月份各等级冻害出现频次依次减少,关中局地在12、2月份未出现过重度冻害。陕北12、1月份0.6≤Cˉ≤0.7,2月份0.5≤Cˉ≤0.7;关中12、2月份0.1≤Cˉ≤0.6,1月份0.2≤Cˉ≤0.7,各月冻害风险年份分析表明冻害风险不同年份间差异大,振幅变化明显。根据上述特征与陕西省设施蔬菜生产现状将陕西省干旱半干旱地区大棚分成冬季温室持续加温区、简易加温区、遇低温临时加温区这3个区域,确定出陕西设施蔬菜加温类型。 展开更多
关键词 陕西 温室 低温冻害 损失率 风险 加温类型
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A Meta-analysis of the Effects of Warming and Elevated CO_2 on Soil Microbes 被引量:7
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作者 FU Gang ZHANG Haorui +1 位作者 LI Shaowei SUN Wei 《Journal of Resources and Ecology》 CSCD 2019年第1期69-76,共8页
Soil microbes play important roles in terrestrial ecosystem carbon and nitrogen cycling. Climatic warming and elevated CO2 are two aspects of climatic change. In this study, we used a meta-analysis approach to synthes... Soil microbes play important roles in terrestrial ecosystem carbon and nitrogen cycling. Climatic warming and elevated CO2 are two aspects of climatic change. In this study, we used a meta-analysis approach to synthesise observations related to the effects of warming and elevated CO2 on soil microbial biomass and community structure. Ecosystem types were mainly grouped into forests and grasslands. Warming methods included open top chambers and infrared radiators. Experimental settings included all-day warming, daytime warming and nighttime warming. Warming increased soil actinomycetes and saprotrophic fungi, while elevated CO2 decreased soil gram-positive bacteria(G+). Mean annual temperature and mean annual precipitation were negatively correlated with warming effects on gram-negative bacteria(G–) and total phospholipid fatty acid(PLFA), respectively. Elevation was positively correlated with the warming effect on total PLFA, bacteria, G+ and G–. Grassland exhibited a positive response of total PLFA and actinomycetes to warming, while forest exhibited a positive response in the ratio of soil fungi to bacteria(F/B ratio) to warming. The open top chamber method increased G–, while the infrared radiator method decreased the F/B ratio. Daytime warming rather than all-day warming increased G–. Our findings indicated that the effects of warming on soil microbes differed with ecosystem types, warming methods, warming times, elevation and local climate conditions. 展开更多
关键词 ecosystem types elevated CO2 increased temperature response ratio warming methods
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