| Millet has played an important role in China’s critical historical period because of its advantages of rich nutrition,drought tolerance,and grain and grass.With the industrialization of regional miscellaneous grains,The Shanxi Provincial Government has issued a series of policies,the planting area has steadily expanded.The large amount of weeds in millet fields has become a major problem for large-scale production of millet.The use of collateral series herbicides(currently not registered special herbicides for millet fields)has a certain impact on the health of the user,whether it is on the yield,quality or possible low residue,Completely contrary to the concept of green and organic development.In this paper,we used a method to investigate the weeds in the millet fields,and clarified the community structure of the weeds in the millet field.The single factor analysis of variance was used to analyze the allelopathy of several dominant weeds in the millet field.Research on the role,to investigate the allelopathy effect of water extract of millet straw on several weeds;to investigate the weed control effect under different combinations(different amounts and different lengths)of straw mulching,to explore the weed control effect and straw mulching The relationship between quantity and straw length.The analysis of the three aspects aims to provide a theoretical basis for the search for green weeding methods in the weeds of grain fields.The main conclusions of this article are as follows:(1)In order to grasp the composition of weed communities in the valleys near Taigu County,we investigated the weeds in the valleys from June to August 2019.It was found that there were 17 families,15 genera and 17 species of common weeds of various types,and 12 species of annual weeds,which accounted for 70.6% of the total number of weeds,far more than perennial weeds,and had a great degree of harm.There are 11 broad-leaved weeds,accounting for 64.7% of the total number of weeds,of which 8species are annual,accounting for 72.7% of the total broad-leaved weeds.The dominant weed families are Gramineae,Amaranthaceae,Chenopodiaceae,and Portulacae,respectively,and their dominance is131.1%,51.3%,44.3%,and 28.4%.There are many kinds and large amounts of weeds in the survey area.The important value of quinoa is 58.4,which is the main control object.(2)In order to explore the allelopathic effects of water extracts from different parts of foxtail straw(leaf and stem)on vicious associated weeds in three kinds of cereal fields including Amaranthus retroflexus,Chenopodium,and Setaria viridis.This test is to study the biological indicators of weed seeds during germination and physiological indicators of potted seedlings,and to study the different concentrations of foxtail millet(leaves,stems)at different concentrations(undiluted,10-fold dilution,50-fold dilution,100-fold dilution).The effects of extracts on the growth of three kinds of weeds,and clarified the allelopathic effect of millet straw water extracts on three kinds of weeds.The finally indicated that the germination rate,germination potential,root length,shoot length,fresh root weight,fresh shoot weight,net photosynthetic rate,stomatal conductance,transpiration rate,Intercellular CO2 of millet leaves and stem water extracts on three weeds.There was a certain allelopathic effect of CO2 concentration(P﹤0.05),and there were differences in the effects of extracts at different concentrations and in different parts.The overall performance is the inhibitory effect of the original solution,and the diluent(10-fold dilution,50-fold dilution,100-fold dilution)promotes the effect.Under the treatment of leaves and stem extracts,the germination rates of the three weeds decreased by 63.9%,37.3%,and 41.7%,respectively,and the root length was only 27.8%,37.8%,and 18.4% of the control.Bud length was only 34.5%,27.7% and 17.6% of the control.Net photosynthetic rate accounted for 66.6%,89.9% and 88.2% of the control.Transpiration rates accounted for 69%,87.5%,and 56.1% of the control.The comprehensive allelopathic effect index on the three weeds was-0.70,-0.72,and-0.80,showing strong allelopathic inhibition.Changes in germination rate,root length,root fresh weight,net photosynthetic rate,stomatal conductance,transpiration rate,and plant height under diluent treatments were firstly increased and then decreased with the increase of the dilution factor,of which 50-fold dilutions promoted The effect is the strongest,and the combined effect index is 0.26,0.22,and 0.17.The intercellular CO2 concentration and intercellular CO2 concentration of weed seedlings were higher than those of the control under the original solution treatment,and were lower than those of the control under the dilution treatment,and the 50-fold dilution was at the lowest level.There are differences in the distribution of allelopathic substances in different parts of millet straw(leaf and stem),which can affect the germination of seed and the growth of seedlings in the field.The growth of associated weeds in the grain field is related to the leaching of allelochemicals in millet straw.(3)In order to clarify the weed control effect under the combination of different length and different quality millet straw,five kinds of straw cover were set,namely 0 kg / hm2,2000 kg / hm2,4000 kg / hm2,8000 kg / hm2,12000 kg / hm2.There are three kinds of straw crushing treatment length,namely 1 cm,3cm,5 cm.A total of 12 combined treatment methods were conducted to investigate the control effect 20 days and 40 days after the straw was covered.The results indicated that: under the combination of different quality and different lengths of straw,when the mass was 2000 kg/hm2 and different lengths were combined and covered,the overall control effect of weeds was-5.5%,And the shorter the smashing length of the straw,the worse the reduction of the prevention effect.When the mass is 4000 kg/hm2,8000 kg/hm2,12000 kg/hm2,the weed plant control effects are 6.0%,22.7%,and 31.1%,and the fresh weight control effects are 7.3%,20.8%,and 35.1%.When the cover length was 1 cm,3 cm,and 5 cm,the control effects of weeds were 15.9%,13.2%,and11.6%,and the fresh weight control effects were 16.6%,14.5%,and 12.2%,which increased with the reduction of the stalk crushing length.Comprehensive allelopathic effects of water extracts from different parts of millet on several kinds of weeds and the study on the control effect of different weight and different length of straw mulch on weed control,we can find that there are certain allelopathic substances in millet straws,and the concentration is high enough It can significantly inhibit the germination of some weed seeds,and as the amount of straw increases and the length of straw decreases(Perishable,allelopathy substances are released faster),the better the weed control effect,the best combination of coverage for this experiment is 12000 kg / hm2 and 1cm length treatment.In practical production,the allelopathic effects of crops on weeds should be studied in more depth.During the process of returning straw to the field,the physical covering effect and the existing allelopathic effect should be combined as much as possible,so that the comprehensive effect of returning straw to the field can be improved. |
