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放牧日期和频率对草原砂芦、砂生须芒草的影响
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作者 Patrick E.Reece Joe E.Brummer +3 位作者 Russell K.Engel brian k.northup Jampes T.Nichols 万里强 《国外畜牧学(草原与牧草)》 1998年第2期28-32,共5页
为了定量描述放牧日期和频率对草原砂芦(Calamovilfa logifolia)和砂生须芒草(An-dropogon hallii)总有机物贮藏量的影响,从1988年起至1992年止进行了5年试验研究。处理包括8种月中放牧期。各处理季节放牧率相等,并均分于各个放牧期内... 为了定量描述放牧日期和频率对草原砂芦(Calamovilfa logifolia)和砂生须芒草(An-dropogon hallii)总有机物贮藏量的影响,从1988年起至1992年止进行了5年试验研究。处理包括8种月中放牧期。各处理季节放牧率相等,并均分于各个放牧期内。在连续4年期间,各放牧处理均在相同草场饲喂一龄牛,且放牧时间均为4~7d。到第5年黄化初春生长产生分蘖技的平均重量可用来估测其有机质总贮备量。试验结果表明,当放牧率与本研究相同时,为避免6月份放牧导致这两种草贮备物的下降,就须使其放牧期延迟长达60d。另外,为使这两种草贮备物的量同时达到高水平,就须延迟放牧至8月中旬或更晚。 展开更多
关键词 黄化生长 放牧日期 放牧频率 短周期放牧 轮牧
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Biochar applications influence soil physical and chemical properties,microbial diversity,and crop productivity:a meta-analysis 被引量:3
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作者 Hardeep Singh brian k.northup +1 位作者 Charles W.Rice P.V.Vara Prasad 《Biochar》 SCIE 2022年第1期1055-1071,共17页
Biochar is a widely known soil amendment.Here we synthesize the available information on influence of biochar application on different soil properties and crop productivity using meta-analysis.Global data on influence... Biochar is a widely known soil amendment.Here we synthesize the available information on influence of biochar application on different soil properties and crop productivity using meta-analysis.Global data on influence of biochar applications on different soil physical,chemical,microbial properties,and crop productivity were extracted from literature and statistically analyzed.Based on selection criteria,59 studies from the literature published between 2012 and 2021 were selected for the meta-analysis.Correlations were developed between effect size of biochar application on different soil properties and crop productivity.Application of biochar increased soil pH,cation exchange capacity,and organic carbon by 46%,20%,and 27%,respectively,with greater effects in coarse and fine-textured soils.Effects on chemical properties were variable among biochar prepared from different feedstocks.Among physical properties,biochar application reduced bulk densities by 29%and increased porosity by 59%.Biochar prepared at higher pyrolytic temperatures(>500℃)improved bulk density and porosity to greater extents(31%and 66%,respectively).Biochar prepared at lower pyrolytic temperatures(<500℃)had a greater effect on microbial diversity(both bacterial and fungal),with more diverse bacterial populations in medium and coarse textured soils,while fungal diversity increased in fine textured soils.Biochar applications increased crop productivity only in fine and coarse textured soil.The effect size of biochar application on crop productivity was correlated with responses to physical properties of soils.The meta-analysis highlighted the need to conduct long-term field experiments to provide better explanations for changes in biochar properties as it undergoes aging,its longer-term effects on soil properties,and timing of re-application of different biochars. 展开更多
关键词 BIOCHAR Crop productivity Microbial diversity Soil physical properties Soil chemical properties
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