庆阳市全膜双垄沟播玉米田杂草种类及优势种群

Weed Species and Dominant Populations in Corn Fields Fully Covered by Plastic Much or Planted in Furrows in Qingyang,Gansu Province

通过对甘肃省庆阳市所辖8个县(区)内160个点全膜双垄沟播玉米田杂草的种类、种群分布调查研究得出,全膜玉米田共涉及杂草17科29属34种,其中杂草优势种9个,按发生频率、相对多度排序依次为:狗尾草(93.75%、62.50%)>反枝苋(83.13%、31.33%)>打碗花(73.75%、28.99%)>藜(70.00%、28.11%)>马齿苋(55.00%、26.02%)>止血马唐(53.75%、18.10%)>毛马唐(46.25%、14.50%)>龙葵(43.75%、10.76%)>地锦(33.75%、10.81%)。全膜玉米田的杂草主要存在5种群落类型。在以自然降雨为主的半干旱的中南部地区(西峰、宁县、正宁、庆城、镇原塬区)主要分布有3种群落类型:狗尾草、毛马唐、打碗花、藜、反枝苋群落,打碗花、狗尾草、无芒稗、藜、反枝苋群落以及芦苇、止血马唐、地锦、打碗花群落,分别占所调查样方数的46.04%、37.07%、14.58%。在以河流水沟灌为主的北部地区(华池、环县、合水川区)主要分布有2种群落类型:马齿苋、藜、反枝苋、狗尾草群落,地锦、狗尾草、无芒稗、藜群落,分别占所调查样方数的58.73%、30.48%。

Weed species and their distribution were studied in corn fields fully covered by plastic much or planted in fur- rows at 160 sites in eight counties （zones） in Qingyang City, Gansu Province. Weeds present in the corn fields belonged to 17 families ,29 genera and 34 species. Nine species were dominant as follows （with their respective percent frequency and abundance in parenthesis） ：Setaria viridis （93.75% ,62. 50% ） ,Amaranthus retroflexus （83.13% ,31.33% ） ,Calys- tegia hederacea （ 73. 75%, 28. 99% ）, Chenopodium album （ 70. 00%, 28. 11% ）, Portulaca oleracea （ 55. 00%, 26.02% ）, Digitaria ischaemum （ 53. 75%, 18. 10% ）, Digitaria ciliaris （ 46. 25%, 14. 50% ）, Solanum nigrum （43.75% ,10. 76% ） ,Euphorbia humifusa （33.75% ,10. 81% ）. There were five main types of weed communities in the sampled area （cornfields with plastic soil cover）. In the central and southern semiarid regions （Xifeng, Ning County, Zhengning, Qingcheng,Zhenyuan plateau areas） that depends on rainfall, there were three types of communities with the following composition ： （ 1 ） S. viridis , D. ciliaris , Calyste- gia hederacea, C. album and A. retroflexus ; （ 2 ） C. heder- acea, S. viridis, Echinochloa crusgalli, C. album and A. retroflexus ; and （ 3 ） Phragmites australis , D. ischaemum , E. humifusa and C. hederacea. These communities com- prised 46.04% ,37.07% and 14.58% of the samples, respectively. In the river- water irrigated northern regions （Huachi, Huan County Heshuichuan areas） the two communities present had the following composition：（4） P. oleracea, C. album, A. retroflexus and S. viridis;and （5） E. humifusa, S. viridis, E. crusgalli and C. album） and accounted for 58. 75% and 30.48% of the investigated samples ,respectively.