不同轮作模式下小麦禾谷孢囊线虫的发生动态和种群密度

摘要

轮作是防治小麦禾谷孢囊线虫的重要农业措施,为了明确青海省春麦区不同轮作模式对小麦禾谷孢囊线虫的控制效果,采用田间大区试验法对生产中应用的6种轮作模式进行了研究.结果表明:不同轮作模式下,小麦禾谷孢囊线虫种群密度变化差异极显著,其中小麦与马铃薯、油菜、蚕豆轮作两年或以上能有效降低小麦禾谷孢囊线虫种群密度,土壤中的孢囊量减少39.31％～84.39％,单孢虫口数量减少73.21 ％～95.35％,虫口密度减少83.76％～97.82％;不同作物间,小麦与马铃薯或蚕豆的轮作效果(虫口密度减少74.39％～79.37％)显著优于小麦与油菜的轮作效果(虫口密度减少67.16％).在同一地块相同条件下,种植油菜、蚕豆、马铃薯、小麦4种作物,小麦禾谷孢囊线虫均能正常孵化,4月底土壤中的2龄幼虫(J2)量增加,5月上旬达到高峰期,5月中旬开始,土壤中的J2、孢囊量、虫口密度和单孢虫口数量均急剧下降,6月至7月份下降幅度小,趋于稳定;田间空孢囊率于5月中旬至6月中旬急剧增加,7月份趋于稳定,8月份以前,4种作物田禾谷孢囊线虫的孵化动态和种群密度变化趋势一致,8月中旬,小麦田随着新孢囊脱落到土壤中,禾谷孢囊线虫种群密度开始上升,小麦收获后土壤中的孢囊量比播种前增加28.62％,虫口密度增加41.30％;而油菜、蚕豆、马铃薯田土壤中的孢囊量比播种前减少32.27％～48.36％,虫口密度减少70.91％～81.73％,8月中旬至10月份小麦田禾谷孢囊线虫种群密度极显著高于油菜、蚕豆、马铃薯田.%Crop rotation is an important agricultural measure to control Heterodera avenae (cereal cyst nematode,CCN).In order to define the effect of different rotation patterns on CCN in high-altitude regions of Qinghai Province,6 rotation patterns were studied in field experiment with regional test method.The results showed that there was significant difference in changes of population density of CCN under different rotation patterns.Rotation of wheat with potato,rape,or broad bean by no less than two years can effectively reduce the population density of CCN.The amount of cysts in the soil decreased by 39.31％-84.39％.The eggs and second stage juveniles (J2) in single cyst dropped by 73.21％-95.35％,and egg density in per gram soil decreased by 83.76％-97.82％.Among different crops,control effect on CCN bv rotation of wheat with potato or broad bean was significant hetter than that by rotation of wheat with rape.The eggs can hatch properly in four plots planting wheat,potato,broad bean or rape in the same field.The J2 amount in the soil increased at the end of April and peaked in early May.The amount of J2 and cysts in the soil,the eggs and J2 in single cyst,and the egg density in per gram soil dropped sharply since mid-May,then declined slightly and tended to be stable in June and July.The empty cysts in the plots increased dramatically in mid-May to mid-June,and tended to be stable in July.The dynamics of egghatching and the changing trends of population density of CCN were consistent before August.The population density of CCN in wheat plot was rising as the cysts fell off into the soil since the middle of August.The amount of cysts in 100 mL soil increased by 28.62％ and the egg density in per gram soil increased by 41.13％ after wheat harvest.However,the amount of cysts in 100 mL soil decreased by 32.27％-48.36％,and the egg density in per gram soil decreased by 70.56％-81.82％ in rape,broad bean and potato plots after harvest.The population density of CCN in wheat plot were significantly higher than those in rape,broad bean,and potato plots from mid-August to October.