The Studay On Ecology And Integrated Management Of Main Kargeleaf Weeds Of Wheat Field In Guanzhong West Area Of Shaanxi

The Galium aparine L. and the Veronica didyma Tenore and the Descurainia Sophia (L) schur and the Copsella bursa-pastoris (L) Medic and the Arenaria serpyllifolia L.are 5 superior weed species of wheat field in Guanzhong west area of Shaanxi. All of them caused extensive occurrence and serious damage. So, to choose the 5 weed species, the objects of this study were to investigate the phenology of 5 kinds of weeds and Biological characteristics and occurrence trend laws in field and effect of chemical control on weed species-colony succession and crowunity in wheat field in Guanzhong west area of Shaanxi, and apply meteorological material and depend on the investigation work basis of the past, further defined 5 weed species Biological characteristics and occurrence trend laws and growth laws in field ,analyse and investigate relations between the various factors about climate factor and environment factor and cultivation administration system and use of chemical herbicides atc. and effect of the various factors on weed species-colony succession and occurrence laws, so as to further work out weed control index and eco-economic threshold and establish weed forecast system to create biology foundation. Results will provide major theory basis for weed effective control and Rational Weed Management. In this study, these results have been achieved:1. Further defined 5 kinds of weeds Biological characteristics in wheat field about The Galium aparine L. and the Veronica didyma Tenore and the Descurainia Sophia (L.) schur and the Copsella bursa-pastoris (L.) Medic and the Arenaria serpyllifolia L. in Guanzhong west area of Shaanxi.2.Different wheat sowing periods and standards of fertility of soil have a great influence on weeds biological characteristics. There is a notably positive interrelation between Sowing periods or standards of fertility of soil and the Weeds Biological indexes. With wheat sowing time postposition and lowering of standard of fertility of soil, the Weeds Biological indexes have a great lowering trend about the weed branche numbers and the leaves numbers and the plant height and the plant weight and the seeds yeild and the 1000grain weight atc.3.Further defined phenology period and sprout time and 2-3 leaves period of 5 kinds of weeds about The Galium aparine L. and the Veronica didyma Tenore and the Descurainia Sophia (L.) schur and the Copsella bursa-pastoris (L.) Medic and the Arenaria serpyllifolia L. in different wheat sowing periods in field in Guanzhong west area of Shaanxi.4.In different years in wheat field in Guanzhong west area of Shaanxi. the occurrence laws and the groth and decline laws of 5 kinds of weeds about The Galium aparine L. and the Veronica didyma Tenore and the Descurainia Sophia (L.) schur and the Copsella bursa-pastoris (L.) Medic and the Arenaria serpyllifolia L. were further defined. The result was testified by investigation and analyse and test in four years, the significant factors in which influenced weed occurrence are wheat sowing time and rainfall after the last ten days of September to the second ten days of October.As the wheat sow early and the rainfall is abundant and the humidity is suitable, so the weed will emergence early and emergence-rate of weeds is high. The weeds will easy form competitive superiority to crops.5.The result further defined the relation between the different cropping systems or the farming way and the weed occurrence. The harm of weed would was reduced notably by crop rotation and periodical deep ploughing of soil for interval 2-3 years.6.By tested on the emergence depth of seeds different weed species in soil, the result further defined the emergence depth of weed seeds of 6 kinds of weeds about The Galium aparine L. and the Veronica didyma Tenore and the Descurainia Sophia (L.) schur and the Copse 11 a bursa-pastoris (L.) Medic and the Arenaria serpyllifolia Land the Avenct fatua L. So as to7.By study on the critical period of competition, the result further defined the critical period of competition between the weed and crop which is the last ten days of November to the last ten days of February next year. The wheat yield loss rate was the smallest in this period for control.8.Use chemical herbicides on weed species have a great influence. At the traditional agriculture farming condition and in a short period, the weed community was remained relative stable and it turn to was made of a few kinds of weed superior species community. After used chemical herbicides and those weed species of which was sensitive for chemical herbicide was controlled, the medicine-resistance or secondary or latent weed species become the superior species. The Galium aparine L. and the Veronica didyma Tenore and the Alopecunis japonicus Steud caused extensive occurrence and serious damage in countrywide wheat field last years. The principal reason is because of in successive many years had used the DPX-L5300 and the DPX-T6376 and the Chlorotoluron in wheat field. The result has important guiding significance for chemical medicine control and useing of herbicide hereafter.