耕作方式对华北寒旱区燕麦田杂草群落结构的影响

Effect of tillage patterns on the structure of weed communities in oat fields in the cold and arid region of North China

为了明确不同耕作方式对燕麦田杂草群落结构及作物生产的影响，依托华北寒旱区定位10年的免耕、深松、翻耕田间试验，并设置10年免耕后翻耕和10年深松后翻耕处理，监测了2种土壤类型下燕麦田不同耕作方式的杂草总密度、优势杂草种类、杂草多样性指数和生物量以及燕麦产量．结果表明：区域杂草群落结构以狗尾草为主；长期免耕下燕麦田不同生育期杂草密度为翻耕的2．20-5．14倍，而长期免耕或深松后翻耕处理的杂草密度与翻耕差异不显著．免耕下砂质栗钙土与壤质草甸栗钙土燕麦田的杂草Shannon多样性指数分别达0．429和0．531，免耕下杂草生物量是翻耕处理的1．35和2．26倍，而燕麦生物产量较翻耕处理减少22．3％和46．2％．表明耕作方式与土壤类型共同决定杂草群落特征．华北寒旱区长期免耕具有促进农田植物群落自然演化、容蓄多年生宿根类杂草的特征，而翻耕具有降低一年生杂草密度、灭除浅位性宿根杂草、激发深位性宿根杂草的特征；杂草多样性与作物高产性相悖演化．

In order to clarify the effects of tillage patterns on farmland weed community and crop production characteristics, based on 10 years location experiment with no-tillage structure , subsoi- ling and conventional tillage in the cold and arid region of North China, and supplementary experi- ment of plowing after 10 years no-tillage and subsoiling, oat was planted in 2 soils under different tillage patterns, and field weed total density, dominant weed types, weed diversity index, field weed biomass and oats yield were measured. The was dominated by foxtail weed （Setaira viridis ） ; results showed that the regional weed community the weed density under long-term no-tillage was 2.20-5.14 times of tillage at different growing stages of oat, but there were no significant differ- ences between conditional Shannon diversity indices and plowing after long-term no-tillage and subsoiling. Field weed were 0.429 and 0. 531, respectively, for sandy chestnut soil and loamy meadow soil under no-tillage conditions, and field weed biomass values were 1.35 and 2.26 times of plowing treatment, while the oat biomass values were only 2807. 4 kg · hm^-2 and 4053.9 kg · hm^-2, decreased by 22.3% and 46.2%, respectively. The results showed that the weed com- munity characteristics were affected by both tillage patterns and soil types. Long-term no-tillage farmland in the cold and arid region of North China could promote the natural evolution of plant communities by keeping more perennial weeds, and the plowing pattern lowered the annual weed density, eliminated perennial weeds with shallow roots, and stimulated perennial weeds with deep roots.