中国典型草原放牧草场蝗虫为害损失及经济阈值的估算(英语)

传统上估算蝗虫在放牧草场为害损失的方法几乎都是用来测定对牧草秋季产量的影响,而实际上,在估算放牧草场蝗虫为害损失及经济阈值时,牧草的现存量而非秋季产量是更应考虑的因素.本文提出了一种适合测定蝗虫对牧草现存生物量影响的新方法,即野外挂笼饲养与蝗虫种群动态相结合的估算方法,并在此基础上组建了放牧草场蝗虫种群经济阈值模型;α_0 α_1M_1_α_2M_2_ α_3S_1 α_4S_2=C其中,M_1:狭翅雏蝗生物量;M_2:宽须蚁蝗生物量;S_1:狭翅雏蝗平均个体重量,S_2:宽须蚁蝗平均个体重量;α_0-α_4:常数.同时引入蝗虫种群数量和生物量两项参数来表达蝗虫种群的发生程度.

ESTIMATION OF ECONOMIC THRESHOLDS FOR GRASSHOPPER DAMAGE ON GRAZING PASTURE IN THE TYPICAL STEPPE OF CHINA

Almost all of the methods traditionally selected to estimate forage damage caused by grasshoppers in grassland are to determine the forage damage in relation to forage yield in fall. But the damage to standing forage, not the forage yields in fall, should be considered in detemining forage damage and economic thresholds in grazing pasture. A new method that combines the field hang-cage rearing with natural grasshopper population dynamics to evaluate the damage to standing forage was presented in this paper. The complex grasshoppers economic threshold models in grazing pasture can be described as-? alMl a2M2 a3Sl ff452 = CWhere MI : biomass of Myrmeleotettix palpalis (Zub. ); M2: biomass of Chorthippus dubius (Zub); Sl: average individual weight of Myr. palpalis; S2: average individual weight of Ch. dubius, aa-at. constants. The level of grasshopper's infestation was described with regard to both grasshopper density and phenology.