Effects Of Fire-control Method On The Characteristics Of Main Weeds Communities In Farmland

Farmland weeds seriously affect the yield and quality of crops.The common route is mainly artificial control and chemical control.The former mainly uses mechanical pressure or man-made grass to carry out,while the latter may cause problems of phytotoxicity or pesticide residue exceeding the standard.Therefore,it is necessary to explore scientific and reasonable ways to prevent and control farmland weeds.This study studied the effects of fire control grass on weed species,dominance,biomass and biodiversity index in summer corn field based on different tillage methods and planting methods at the Doukou Crop Experiment Demonstration Station of Northwest A&F University.Summer leisure field and winter wheat fields further studied the effects of fire control grass on the species and quantity of weeds,in order to clarify the effect and suitable period of flame control grass,and provide theoretical basis for flame control grass technology.The test yielded the following results:(1)The weed species in the summer corn field in Guanzhong Irrigation District are mainly:foxtail,purslane,scutellaria,valerian,crabgrass,ramie,leeks,fragrant a conite,Solanum nigrum,gray ash,thorn,Convolvulus,Chicory,etc.The results of relative dominance calculation showed that foxtail,purslane,scorpion scorpion,frag rant aconite,crabgrass and valerian were the dominant weeds in summer corn field.(2)The average species and fresh weight of weeds in summer corn field under no-tillage were 6.37 species/m~2,2834.59g/m~2,respectively.The average species and fresh weight of weeds under rotary tillage were 5.10 species/m~2,2387.91 g/m~2,respectively,compared with no-tillage method,the weed species and fresh weight decreased under rotary tillage,indicating that rotary tillage is beneficial to the control of weeds in summer corn field.The rotation of rotary tillage was also reduced compared with the rotation of weeds.In the three tillage methods,the grass damage was the lowest in the field under the rotary tillage method.(3)The effect of planting methods on weed species was not significant.The weed species of two rows of cowpea planting in corn jointing stage,anthesis stage and dough stage were 5.28 species/m~2,6.06 species/m~2,5.00 species/m~2,respectively.,the type of weeds in the three stages was 6.00 species/m~2,6.58 species/m~2,5.11 species/m~2,and the weed species under the two rows of cowpea intercropped in each period were smaller than the corn monoculture.The main types of weeds in the field of summer corn field under different planting methods were foxtail,crabgrass and purslane,indicating that the species of dominant weeds remained basically unchanged;in different growth stages,the weeds of farmland were rich.Both the index and the uniformity index showed corn monocrop>corn intercropped as cowpea.Compared with corn monocropping,corn intercropped cowpea can better control weeds,and weeds decrease with the increase of cowpea density.(4)The average weed species,fresh weight and density of summer corn field in flame control grass(ie,flame treatment topsoil measures)were 5.29 species/m~2,394.25g/m~2 and352.70 plants/m~2,respectively.The weed species,fresh weight and density were 5.94species/m~2,443.82g/m~2 and 346.31 plants/m~2,respectively.Compared with the control,the weed species and fresh weight decreased under flame control,and the density increased.Both the weed richness index and the Simpson index have declined.The weeds index and evenness index were higher in the jointing and anthesis stages than in the control.It can be seen that although the measures to control the weeds by the flame treatment of the topsoil have an effect,the grass control effect is not satisfactory.(5)Summer leisure field experiments showed that the control of weeds in the three-leaf stage of weeds can effectively inhibit the growth of weeds.After three times of three-leaf stage flame control,flaming can control the growth of weeds,but the control effect is poor for the weed of Fragrant aconite(6)The foxtail,the sage,and the stalk are the main weeds of the winter wheat field.Before the winter wheat was sealed,the three-leaf weeds were used to control the grass between the rows,which could significantly reduce the type and quantity of weeds in the field.The herb control effect was equivalent to the herbicide weeding effect.