不同耕作模式对大豆田土壤杂草种子库的影响

Effects of Different Tillage Patterns on Soil Weed Seedbank in Soybean Field

[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。

[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 soybeanmaize 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 to 16 families in the tillage soybean field,a total of 26 weed species belonged to 15 families in the no tillage 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 Solanum 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- 25 cm,and the density and the relative advantages of Echinochloa crus-galli（ 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-tillage 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.