不同耕作模式对大豆田土壤杂草种子库的影响

目的]明确不同耕作模式对大豆田土壤杂草种子库的影响。方法]采用杂草种子萌发法,调查玉米大豆轮作区翻耕和免耕2种耕作模式下大豆田0~30 cm土层土壤杂草种子库组成及特征。结果]2013—2015年调查统计结果表明,翻耕大豆田杂草共有16科28种,免耕大豆田杂草共有15科26种,有22种杂草在翻耕和免耕大豆田均有分布。翻耕田主要优势杂草为稗草、铁苋菜、龙葵、藜和委陵菜,免耕田主要优势杂草为龙葵、铁苋菜、稗草、藜和马唐,杂草类型以阔叶杂草为主,禾本科杂草较少。翻耕大豆田杂草种子库密度为3 248.2粒/m2,主要分布在0~5、15~20、20~25 cm土层,其中稗草的密度和相对优势度最高;免耕大豆田杂草种子库密度为3 181.5粒/m2,主要分布在0~5、20~25、25~30 cm土层,其中龙葵密度和相对优势度最高。不同耕作模式优势杂草在土层中的分布有一定差别,稗草在翻耕田主要分布于0~5、10~15、20~25 cm土层,而在免耕田主要分布于20~25 cm土层;龙葵在翻耕田主要分布于5~10、20~25 cm土层,而在免耕田主要分布于20~25 cm土层。结论]免耕和翻耕对大豆田杂草种子库密度影响不大,不同耕作模式对杂草相对优势度和土壤中的垂直分布有一定影响。

Effects of Dif erent Tillage Patet rns on Soil Weed Seedbank in SoybeanFi eld

Ab srt act Objective] The aim was to explore effects of different tillage patterns on soil weed seed bank in soybean field.Method] The composition and species diversity of soil weed seedbank in soybean field 0-30 cm soil layer under two different tillage patterns from soybean-maize rotation area by using the method of weed seed germination . Result] The results of comprehensive survey in 2013-2015 showed that, a total of 28 weed species belonged to16 families in the tillage soybean field, a total of 26 weed species belonged to 15families in the no till -age soybean field. There were 22 kinds of weeds in tillage and no tillage soybean field.The main advantage weeds were Echinochloa crus-galli ( L.) , Acalypha australis L., Solanum nigrum L.,Chenopodium album Linn., Potentilla chinensis Ser.in the tillage soybean field and Sola-num nigrum L., Acalypha australis L., Echinochloa crus-galli ( L.) , Chenopodium album Linn., Digitaria sanguinalis ( Linn.) Scop.in the no tillage soybean field.Broad leaved weeds are the main weeds, less gramineous weeds in the type of weeds.The density of weed seed bank was 3 248.2 grains/m2 , more weeds located in the soil layer of 0-5, 15-20, 20-25cm , and the density and the relative advantages of Echinochloa crus-gali (L.) was the highest under tillage soybean field.The density of weed seed bank was 3 181.5 grains/m2, and more weeds located in the soil layer of 0-5, 20-25, 25-30 cm, the density and the relative advantages of Solanum nigrum L.was the highest under no-tillage soybean field.There were quite different in the soil distribution of dominant weed species.Echinochloa crus-galli ( L.) was mainly distributed in 0-5, 10-15, 20-25 cm soil layer under the tillage soybean field, and it was in the 20-25 cm soil layer under no-till-age soybean field was mainly distributed.Solanum nigrum L.was mainly distributed in 5-10, 20-25 cm soil layer under the tillage soybean field, and it was in the 20-25 cm soil layer under no-tillage soybean field was mainly distributed.Conclusion] There were a little effect on density of weed seed bank under no-tillage and tillage of soybean field.Different tillage patterns had certain effect on the relative dominance of weeds and the vertical distribution in soil.