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湘南烟蚜发生量趋势预测方法研究 被引量:4
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作者 陈永年 徐双红 +1 位作者 龙建中 李小一 《植物保护》 CAS CSCD 北大核心 2001年第6期22-25,共4页
据宁远、郴州、芝山 3地 15年烟田蚜量系统调查 ,湘南烟蚜种群消长均为单峰型 ,符合抛物线方程。以百株蚜量lg值为预报量 (Y) ,以 5个气象因子及烟草生育期作预报因子 (Xi) ,对Y及Xi 作 0、1化处理 ,采用指标交叉法建立预报方程。结果表... 据宁远、郴州、芝山 3地 15年烟田蚜量系统调查 ,湘南烟蚜种群消长均为单峰型 ,符合抛物线方程。以百株蚜量lg值为预报量 (Y) ,以 5个气象因子及烟草生育期作预报因子 (Xi) ,对Y及Xi 作 0、1化处理 ,采用指标交叉法建立预报方程。结果表明 ,对蚜量波动影响最大的前 6项因子依次为日平均气温 (X2 )、日最高气温 (X3 )、两次调查期间的总日照时数 (X5)及X2 X5、X3 X5、X2 X3 。在天气预报准确的条件下 ,蚜量变动趋势预报的准确率可达 88 9%。 展开更多
关键词 烟蚜 种群动态 预测预报 虫害发生量
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Investigation on Effect of Forestation by Mixing Pinus massoniana with Schima superba
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作者 HUANGWenchao HUANGLili 《Chinese Forestry Science and Technology》 2004年第2期26-33,共8页
Since forestation of pure forest of Pinus massoniana is liable to suffer from pest calamity, soilerosion, decrease of soil fertility, and difficulty in wood production in the hilly areas of southern China, weconducted... Since forestation of pure forest of Pinus massoniana is liable to suffer from pest calamity, soilerosion, decrease of soil fertility, and difficulty in wood production in the hilly areas of southern China, weconducted an investigation on the three types of forests in Gaoan County of Jiangxi Province, namely, thepure forest of Pinus massoniana, the pure forest of Schima superba, and the mixed forest consisting of thetwo species, setting up standard stand, measuring and studying the growing stock, biomass, leaf area, roots,soil, vegetation, pests, litters, soil erosion, microclimate, etc., with the following results. ① The averageheight, diameter at chest height, and volume of the mixed forest are higher than those of the pure forest ofPinus massoniana by 30.9%, 31.7% and 10.6%, respectively. ② The biomass of the mixed forest is 2.24times as much as that of the pure forest of Pinus massoniana. ③ The litters of the mixed forest is 3.37 timesand 1.96 times as much as the litters of the pure forest of Pinus massoniana and the pure forest of Schimasuperba respectively. ④ The occurrence of pest calamity per tree is lower and the conditions of soil erosionand microclimate are better than those of the pure forest of Pinus massoniana. ⑤ The mixed forest of the twospecies is an excellent mixed type of needle-leaf and deciduous forest worth being popularized in Chinassubtropical areas, especially in the low hilly areas. It is recommended in plantation that the mixed patterns bebetween trees, lines, small blocks, or scattered-dots, the ratio of mixture of Pinus massoniana and Schimasuperba be 5 to 1, or 3 to 1, and the initial space between trees be 1.2, 1.5, or 2.0 m while the initial densitybe 6 944 to 4 440 trees per square hectare. 展开更多
关键词 Pinus massoniana Schima superba mixed forest effect of forestation
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