Study On Corn-weed Community Niche In Shenyang Region

The experiment (A) in 2005 has four treatments:Ⅰhigh dense and no fertilize,Ⅱlowdense and no fertilize,Ⅲhigh dense and fertilize,Ⅳlow dense and fertilize; the experiment (B)in 2006 has three treatments:ⅰplastic mulching,ⅱno weeding measure, CK. The textanalyses breadth and overlap of horizontal niche, vertical niche, temporal niche and so on incornfield corn-weed community. Investigations on the constitute and quantity change ofspecies, comparability of corn-weed communities under different treatments, dynamic ofhabitat in northern glebe community are probed.Horizontal niche breadth in turn is Echinochloa hispidula(Retz.), Abutilon theophrastiMedicus Malv., Polygonum orientale L., Zea mays L, Acalyhpa wilkesiana, Amaranthusretroflexus L., Ch.acuminatum willd., H.scandens(Lour.) Merr. from high to low. Verticalniche breadth Zea mays L.＞Polygonum orientale L.＞Ch.acuminatum willd.＞Amaranthusretroflexus L.＞Abutilon theophrasti Medicus Malv.＞Echinochloa hispidula(Retz.)＞Acalyhpa wilkesiana＞H.scandens(Lour.) Merr.. Temporal niche breadth of Zea mays L. isthe highest and Ch.acuminatum willd, is the lowest. Intergrate analysis shows that the nichebreadth of Zea mays L. is the highest, and it is dominat species. Echinochloa hispidula(Retz.)is subdominant species, H.scandens(Lour.) Merr. is the lowest.As far as Zea mays L., the horizontal niche overlap of Zea mays L.- Abutilon theophrastiMedicus Malv. is the highest, the horizontal niche overlap of Zea mays L.-H.scandens(Lour.)Merr. is lowest. The vertical niche overlap of Zea mays L.- Polygonum orientale L. is thehighest, the vertical niche overlap of Zea mays L.- H.scandens(Lour.) Merr. is lowest. Thetemporal niche overlap of Zea mays L.- Polygonum orientale L. is the highest, the temporalniche overlap of Zea mays L.- Echinochloa hispidula(Retz.) is lowest. Intergrate analysisshows that the niche overlap of Amaranthus retroflexus L.- Ch.acuminatum willd, is thehighest, the niche overlap of Ch.acuminatum willd.- H.scandens(Lour.) Merr is the lowest. Asfar as Zea mays L., the niche overlap of Zea mays L.- Abutilon theophrasti Medicus Malv. isthe highest, the niche overlap of Zea mays L.- H.scandens(Lour.) Merr. is lowest.Community similarity coefficient betweenⅠandⅣis the biggest; community similaritycoefficient betweenⅠandⅢis the smallest in whole breeding season. Wind speed of parallel with ridge＞wind speed of vertical with ridge. Wind speed inupper crown is the strongest, which of Ck is stronger than ii. With height increasing,temperature in community is increasing. Temperature at upper crown is highest, which on theground is opposite. Temperature of ii is slightly higher than that of CK. With heightincreasing, humidity in community is decreasing. Humidity at upper crown is lowest, whichon the ground is opposite.Humidity in antemeridiem is higher than that in afternoon at thesame height. Humidity of ii is slightly higher thart that of CK.