Mechanism Research Of The Competition Between Invasive Weeds And Crops Under The Conditions Of Different Water Supply

In order to study the adapting mechanism of an invasive weed—Amaranthus retroflexusresponse to the water resource fluctuations, and the competition mechanism between crops andweeds in the process of invading agro-ecosystem, through the artificial simulation of waterfluctuations in different conditions (high water model, water model and low water mode), comparedifferent species competition combination (monoculture of Glycine max, monoculture ofAmaranthus retroflexus, mixture of Glycine max and Amaranthus retroflexus), the rule ofAmaranthus retroflexus and Glycine max response to morphological index, biomass accumulation,antioxidant content, soil moisture and plant water content.The results show that the water resource fluctuations had effect on plant height of typical cropof Glycine max and an invasive weed—Amaranthus retroflexus, along with the growth of plant,the higher irrigation water is, the higher plant height is. Because of Amaranthus retroflexuscompetition with Glycine max, the height of soybean is reduced, and mixture of Amaranthusretroflexus show superiority, growing trend is better, plant height is higher.Water resource fluctuations had also influence in biomass of Glycine max and Amaranthusretroflexus. Along with the growth period, the higher the mount of water supply, the biomass ofGlycine max is higher. In the drum grain period, total biomass and the biomass of reproductiveorgans of Glycine max is maximum. Amaranthus retroflexus compete with Glycine max, totalbiomass of Glycine max and biomass of various organs are lower than biomass of monocultureplant; total biomass of Amaranthus retroflexus and biomass of different organs is higher thanbiomass of monoculture plant. In seedling stage and flowering podding period, stem and leafbiomass of Glycine max accounts for a bigger proportion, stem biomass of Amaranthus retroflexusaccounts for a larger proportion in the whole growth period, and the proportion of reproductiveorgan biomass of Glycine max and Amaranthus retroflexus is larger at the drum grain and ripestage.From seedling to flowering podding stage, monoculture of Glycine max and Amaranthusretroflexus rootshoot ratio has a rising trend, later period rootshoot ratio is decreasing. Glycinemax and Amaranthus retroflexus exist competition, as the growth duration rootshoot ratio is decreasing. This study measured leaf area of Glycine max increases with increasing mount of water,and leaf area of mixed soybean is less than leaf area of monoculture soybean, and leaf area ofmixed Amaranthus retroflexus is greater than leaf area of the monoculture plant. From seedling toflowering podding period, growth rate of Glycine max and Amaranthus retroflexus is faster underthe condition of water model, that biomass accumulation of net efficiency is higher, and the drumgrain of relative growth rate is negative, the biomass decreased in recent maturity period.The content of soybean with growth stage of proline content increased gradually. Non waterdeficit condition, progress with the growth of the soybean proline increased gradually, whichexplains the high, water treatment increased proline content in soybean. Low water treated soybean,proline accumulation of proline in plant drought shows favorable, improve the water retentionability of drought resistance in soybean leaves to increase proline way. The MDA content ofsoybean showed lower water content> water content> high water content, MDA content insoybean processing high content is lowest, the high content of soybean cell membrane lipidperoxidation and the harm is not obvious, strong resistance to drought. Amaranthus retroflexusduring the whole growth period, the content of MDA increased slightly, remained basicallyunchanged, that Amaranthus retroflexus cell membrane lipid peroxidation and the harm is notobvious, strong resistance to drought.Soil moisture is mainly affected by water supply, water supply, the greater the soybeans andAmaranthus retroflexus, the greater the soil moisture content. Along with the growth period topromote soybean and soil moisture content of Amaranthus retroflexus presents downward trend.Flowering soybean podding stage and drum stage period, due to the higher temperatures, thevegetation water consumption and soil evaporation intensity increasing, soil moisture content islow. Amaranthus retroflexus soil moisture content is higher than soybean soil moisture content,shows that soy than Amaranthus retroflexus absorption using water more.To sum up, Amaranthus retroflexus can successfully invade farmland ecosystem, quickly adaptto environment by the fluctuation of the water is because of Amaranthus retroflexus can absorbwater quickly, and efficiently into use, the growth process will moisture mainly exist in stems andreproductive organs; And Amaranthus retroflexus and stronger ability to resist the drought stress,and crop competition, quickly.