Study On Green Grass Control Technology Of Rice-Duck Farming

In order to explore the control effect of Rice-Duck farming,the laboratory has conducted continuous Rice-Duck farming in the same field since 1999.Based on the previous work of graduate students in the laboratory,this paper continued to study the effect of weed control in 2017-2018.The results showed that the weed density decreased with the increase of years.In the control area the total weed density decreased from 169.0 plants/m2 in 2000 to only 11.8 plants/m2 in 2018.The total weed density in the Rice-Duck farming experimental area decreased from 23.3 plants/m2 in 2000 to 2.3 plants/m2 in 2018,and the annual weed density was lower than that in the control area.In the early stage of Rice-Duck farming,the density of Monochoria vaginalis.,Cyperus difformis.,Ludwigia prostrata.,Ammannia baccifera.,Lindernia procumbens.and Leptochloa chinensis.decreased rapidly and fluctuated in a low level range or was exhausted,which was a rapid depletion type.Occasional weeds include Scirpus juncoides.,Sagittaria pygmaea.,Ammannia baccifera.,Alternanthera philoxeroides.,Echinochloa caudata.,Paspalum paspaloides.,Cyperus iria.Long-term existence weeds include Echinochloa crusgalli.and Rotala indica.Shannon-wiener index(H’)and Margalef richness index(R)decreased significantly,and Pielou evenness index(E)and Simpson dominance index(D)reflected the stable state of the community.On the whole,the weed seed bank in the paddy field is developing towards the direction of decreasing number,decreasing diversity and stabilizing community.From 1999 to 2018,Rice-Duck farming could effectively control weed seed banks.From 1999 to 2018,the seed density of grassy weed was reduced by 95.16%,that of broadleaf weeds by 96.99%,that of sedge weeds by 94.73%,that of wheat weeds by 96.21%,that of rice weeds by 96.6%,and that of the total weed seed bank by 96.41%.From the view of the vertical distribution of weed seed bank,the Rice-Duck farming changed the vertical distribution of seed bank density and species from the upper>middle>lower layer to the upper,middle and lower layer,which tended to be evenly distributed.On the basis of long-term Rice-Duck farming,in order to further control weeds and seed bank,the changes of above-ground weed community and underground seed bank under different ecological control measures of Rice-Duck farming were studied in the laboratory from 2013 to now.On the basis of continuing the previous work of graduate students in the laboratory,this paper continued to study the effect of grassland control from 2017 to 2018.In order to control weeds and seed Banks,the overground weed communities and underground seed Banks under Rice-Duck farming and different ecological control measures were studied.The three control measures were:A Rice-Duck farming,B Rice-Duck farming+interception+net fishing,C Rice-Duck farming+interception.The overground weed density tended to be stable after a certain number of years of Rice-Duck farming,and the difference was not significant.The overground weed density decreased significantly after the treatment of Rice-Duck farming+net fishing+interception for one year.The weed control effect from 2013 to 2018 was 69.35%,and the occurrence of Echinochloa crusgalli.was significantly reduced.Under C treatment,Rice-Duck farming+interception,the weed control effect from 2013 to 2018 was 66.1%,which also had a significant control effect on Echinochloa crusgalli..The results showed that both B and C treatments could significantly reduce the overground weed density,the control effect show B>C>A,net fishing+interception treatment could effectively prevent and control weeds.From the perspective of seed bank,the weed seed density of grassy weed,wheat weed,rice weed and the total seed bank decreased significantly after the addition of net fishing and interception treatment,but the control effect on broadleaf weed seed density was non-significant.The main weed species in this paddy field were selected and the control mechanism of Rice-Duck farming was studied,it is of great significance to the improvement and promotion of the organic agriculture.The survival rate and biological characteristics of Alternanthera philoxeroides.Rotala indica.,Monochoria vaginalis.,Leptochloa chinensis.,Echinochloa crusgalli.,Cyperus difformis.,weedy rice and rice were studied in Rice-Duck farming field after cultivated in the hole dish until 6-8 leaf stage.The results showed that after one week,Leptochloa chinensis.,Echinochloa crusgalli.,Cyperus difformis.,weedy rice and rice all survived without being affected;Alternanthera philoxeroides.and Rotala indica.only one plant survived with a survival rate of 8.33%and 0%respectively.In the field of Rice-Duck farming,the water content of the leaves of broadleaf weeds Alternanthera philoxeroides.Rotala indica.,Monochoria vaginalis.were significantly higher than that of Leptochloa chinensis.,Echinochloa crusgalli.,weed rice and rice.Rice-Duck farming had significant effects on predation and control of broad-leaved weed.