谷子秸秆浸提液及田间覆盖对4种杂草的化感作用研究OA北大核心CSTPCD

In order to explore the allelopathic effects of foxtail millet straw extracts and field mulching on Amaranthus retroflexus L.,Chenopodium album L.,Setaria viridis(L.)Beauv,and Echinochloa crus-galli(L.)Beauv in foxtail millet field,five treatments of foxtail millet straw extract(W0,undiluted,100 g/L;W1,10 × dilution;W2,50 × dilution;W3,100 × dilution;CK1,distilled water control)were set up in the petri dish experiment.The effects on seed germination rate,root length,bud length,germination rate allelopathic index,root length allelopathic index,bud length allelopathic index and comprehensive allelopathic index of four weeds were determined.In the field experiment,the straw(F)and plastic film(PF)mulching treatments with the same shading amount were set up.The foxtail millet straw mulching amount were 2 000(F1),4 000(F2),8 000 kg/hm2(F3),and the shading amount were 50％(PF1),70％(PF2),100％(PF3),with no straw mulching as the control(CK2)to determine the plant number,density,coverage and weed control effect of four kinds of weeds in the field.The results showed that:Compared with CK1,the water extract of foxtail millet straw had significant allelopathic effects on the germination rate,root length and bud length of four kinds of weed seeds,and there were significant differences among different concentrations of aqueous extract.The germination rate,root length and bud length of four weed seeds were all inhibited under W0 treatment.The inhibition effect on the germination of four kinds of weed seeds from strong to weak was as follows:C.album(-0.86)＞S.viridis(-0.84)＞E.crus-galli(-0.51)＞A.retroflexus(-0.44).The allelopathic inhibition effect on the root length of A.retroflexus(-1.00)and the bud length of E.crus-galli(-0.84)was stronger.W,and W2 dilution treatments showed allelopathic promotion effects on the seed germination of four weeds,the allelopathic indexes from high to low was as follows:S.viridis(0.19)＞A.retroflexus(0.16)＞E.crus-galli(0.05)＞C.album(0.02).W3 treatment showed a weak allelopathic effect on the seed germination of S.viridis,E.crus-galli and A.retroflexus.In the field experiment,the density and total coverage of four weeds decreased gradually with the increase of straw mulching.F3 treatment still had significant allelopathic inhibition on the density of C.album,S.viridis and E.crus-galli after 5 d of the third moderate rain,and the density three weeds respectively decreased by 61.66％,63.67％and 86.68％compared with CK2.The total coverage of weeds after 5 d of three moderate rains reached the lowest in F3 treatment,and the total coverage of weeds respectively decreased by 24.23％,33.73％and 13.56％compared with CK2.After 5 d of the first moderate rain,the control effects of F,and F2 treatments were higher than that of PF1 and PF2 treatments significantly.The concentration of soil allelochemicals increased after the straw was leached by rainwater,and the allelopathic inhibition effect was enhanced,which increased by 5.23％and 19.09％,respectively.The fresh weight control effect of F3 treatment reached the maximum value of 52.45％after 5 d of the first moderate rain,and the plant control effect reached the maximum value of 68.75％after 5 d of the second moderate rain.With the extension of straw mulching time and the increase of rainfall times,the allelopathic inhibition of straw on weed coverage and density gradually weakened.In summary,the inhibitory effect of foxtail millet straw extract(100 g/L)treatment on seed germination,root length and bud length of four weeds was the most significant,and the foxtail millet straw mulching amount of 8 000 kg/hm2(F3)can replace plastic film mulching for weed control in millet field.