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剑阁县驿道古柏资源调查初报 被引量:3
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作者 伏建芳 唐天勇 +4 位作者 何显平 程建伟 李珣 符建荣 喻丁香 《四川林业科技》 2018年第6期97-101,共5页
剑阁县古柏资源丰富,为世界上保存最完整、规模最大的古柏林,是优质的种质资源,对剑阁县古柏资源的特征研究,可以为其保护提供前期数据。本研究通过对剑阁县古柏资源的调查,从数量、结构、生长状况和影响因素等方面,分析其基本特征,结... 剑阁县古柏资源丰富,为世界上保存最完整、规模最大的古柏林,是优质的种质资源,对剑阁县古柏资源的特征研究,可以为其保护提供前期数据。本研究通过对剑阁县古柏资源的调查,从数量、结构、生长状况和影响因素等方面,分析其基本特征,结果表明:(1)剑阁县驿道古柏现有7 826株,但空间分布不均匀,主要分布在龙源镇和禾丰乡;(2)古柏树龄结构呈单峰曲线的分布规律,且峰值为700 a~899 a;(3)古柏生长状况与树龄无显著相关性,与冠幅、保护措施呈极显著正相关,与影响因素呈极显著负相关,以土壤因素和人为因素对其影响最大。 展开更多
关键词 古柏 结构特征 生长状况 影响因素 剑阁县
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Effects of Nitrogen Application Level on Rice Nutrient Uptake and Ammonia Volatilization 被引量:16
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作者 YU Qiao-gang YE Jing +6 位作者 YANG Shao-na fu jian-rong MA Jun-wei SUN Wan-chun JIANG Li-na WANG Qiang WANG Jian-mei 《Rice science》 SCIE 2013年第2期139-147,共9页
The effects of different nitrogen application levels on nutrient uptake and ammonia volatilization were studied with the rice cultivar Zheyou 12 as a material.The accumulative amounts of nitrogen,phosphorus and potass... The effects of different nitrogen application levels on nutrient uptake and ammonia volatilization were studied with the rice cultivar Zheyou 12 as a material.The accumulative amounts of nitrogen,phosphorus and potassium in rice plants across all growth stages showed a trend to increase with increasing nitrogen application levels from 0 to 270 kg/hm 2,but decreased at nitrogen application levels exceeding 270 kg/hm 2.Moreover,the accumulative uptake of nitrogen,phosphorus and potassium by the rice plants was increased by application of organic manure in combination with 150 kg/hm 2 nitrogen.The nitrogen uptake was high during the jointing to heading stages.Correlation analysis showed that rice yield was positively correlated with the accumulative uptake of nitrogen,phosphorus and potassium by the rice plants.The highest correlation coefficient observed was between the amount of nitrogen uptake and rice yield.The rate and accumulative amounts of ammonia volatilization increased with increasing nitrogen fertilizer application level.Compared with other stages,the rate and accumulative amount of ammonia volatilization were higher after base fertilizer application.The ammonia volatilization rates in response to the nitrogen application levels of 270 kg/hm 2 and 330 kg/hm 2 were much higher than those in the other treatments.The loss of nitrogen through ammonia volatilization accounted for 23.9% of the total applied nitrogen at the nitrogen application level of 330 kg/hm 2. 展开更多
关键词 RICE NITROGEN nutrient uptake ammonia volatilization
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