氮肥施用量对稻飞虱与稻叶蝉及其捕食性天敌种群的影响*

为评价氮肥对田间稻飞虱和稻叶蝉及其捕食性天敌种群密度和种群动态的影响,在田间设立0、90、150和210 kg ha-1四个氮肥水平,研究田间白背飞虱、褐飞虱、灰飞虱、黑尾叶蝉、电光叶蝉和二点叶蝉以及捕食性天敌拟水狼蛛、驼背额角蛛、食虫沟瘤蛛和黑肩绿盲蝽的平均密度和种群密度的时间动态。结果表明,210 kg ha-1氮肥水平下,稻田白背飞虱、灰飞虱及稻飞虱(三种飞虱之和)的平均密度均显著高于0、90和150 kg ha-1稻田。0、90、150和210 kg ha-1氮肥稻田间,黑尾叶蝉、电光叶蝉、二点叶蝉和稻叶蝉(三种叶蝉之和)以及拟水狼蛛、驼背额角蛛、食虫沟瘤蛛和黑肩绿盲蝽的平均密度均无显著差异。不同氮肥施用量田间稻飞虱与稻叶蝉及捕食性天敌种群密度的时间动态走势基本一致。表明高水平的氮肥施用会显著促进田间稻飞虱种群密度增多,但对稻叶蝉及捕食性天敌种群密度均无显著影响。

Effects of nitrogenous fertilization on the population dynamics of rice planthoppers, leafhoppers and predators

A field trial was carried out to assess the population density and temporal dynamics of density of Sogatella furcifera, Nilaparvata lugens, Laodelphgax striatellus, Nephotettix cincticeps, Deltocephalus dorsalis, Cicadula fasciifrons, Pirata subpiraricus, Gnathonarium gibberum, Ummeliata insecticeps and Crytorrhinus lividipennis by using different nitrogenous levels 0, 90, 150 and 210 kg/hm2. The results showed that: the population densities of the three rice planthoppers in 210 kg/hm2 treatment were significantly higher than those in 0, 90, 150 kg/hm2 treatment; no significant difference of population density of the three rice leafhoppers, and Pirata P. subpiraricus, G. gibberum and U. insecticeps was found among all the treatments; moreover, temporal dynamics of density of rice planthoppers, leafhoppers and their predators were basically consistent in different nitrogenous fertilization levels. The results indicated that high nitrogenous fertilization could significantly increase the population density of rice planthoppers, but had no significant influence on population dynamics of rice leafhoppers and their predators.