不同土层和水层深度对国内15个杂草稻种群出苗的影响

Effects of soil and water depth on germination rates of fifteen weedy rice populations in China

为了探寻土层和水层深度对杂草稻种群出苗的影响,以中国15个杂草稻种群为研究对象,测定了它们在湿润条件不同播种深度(0～3 cm)、淹水条件下不同播种深度(0～3 cm)和不同淹水深度(0～3 cm)下的出苗率。结果显示:在湿润状态下,供试种群的出苗率随土层深度的增加而降低,播后7 d,铁岭和沈阳杂草稻种群的出苗率受土层深度的影响较小;播后14 d,铁岭、沈阳和丹东种群的出苗率受土层深度的影响相对较小,在土层深度2cm和3 cm下,出苗率仍保持50%以上。在淹水情况下,所有种群的出苗率均随土层深度增加而明显降低,播后7d在1 cm土层深度下供试种群出苗率显著降低,在2 cm土层深度下供试种群基本不出苗;播后14 d,土层深度1cm条件下,铁岭、沈阳、丹东和内蒙古种群能保持45%以上,其他种群的出苗率均低于35%;土层深度在2 cm时,出苗率降低最为明显,都不超过30%,土层深度为在3 cm时供试杂草稻种群不出苗;在不同淹水深度下,铁岭和内蒙古种群的出苗率受水层深度的影响在供试种群中最小。表明:杂草稻种子在土壤中的深度能显著影响出苗率,因此深耕能降低对土层深度敏感的杂草稻种子的萌发,从而降低杂草稻对栽培水稻的危害;淹水能显著降低供试杂草稻种子的萌发率,但对不同杂草稻的影响不完全相同,因此可以根据不同地区杂草稻对土层和水层的不同反应进行管理,以降低杂草稻的危害。

In order to study the influence of different soil depths（0-3 cm） and water depths（0-3 cm） on emergence rates of weedy rice populations,germination rates of 15 weedy rice populations of China both in moist and flooding conditions were assayed in greenhouse.The results demonstrated that the germination rates of the populations were affected significantly by soil depth under moist condition except the populations of Shenyang and Tieling at 7 d after seeding.The germination of weedy rice Tieling,Shenyang and Dandong were less affected by soil depth,kept more than 50% of germination rate at 2-and 3-cm soil depth under moist condition.Under flooding condition,at 7 d after seeding,germination rate of all weedy populations decreased significantly at 1 cm soil depth,and most weedy rice populations didn＇t germinate at 2-cm soil depth.At 14 d after seeding,the germination rate of weedy rice Tieling,Shenyang,Dandong and Neimenggu stayed more than 45% at 1 cm soil depth.All weedy rice populations＇ germination rates declined rapidly to 30% at 2 cm soil depth,and didn＇t germinate at 3 cm soil depth.The germination rates of weedy rice Tieling and Neimenggu were less affected by water depth.The above results indicated that the soil depth may influence the germination of weedy rice.Therefore,deep-tillage might reduce the germination rates of the populations of weedy rice which are susceptible to soil depths and thereby alleviate the harm to cultivated rice.Flooding reduced the germination rates of weedy rice significantly;however,the influence varied.Therefore,the emergence rates of weedy rice may be reduced by keeping a certain depth of water before rice planting.