Studies On The Cultivation Techniques Of Glyphosate-resistant Soybean In The High-lantitude And Cold Region Of Northeast China

The climate in the north part of northeast China is cold, and continuous cropping is popular insoybean production, resulting in complicated weed communities in the field. Effects of existing soybeanherbicides are affected by a number of factors, such as the environment, climate, weed species weed age,etc. Therefore, the weed control is not completed and herbicide injuries occurs frequently, which causesyield reduction of soybean crop and low economic benefits.In the practice, sprading in seeding stage isoften used as a weed control method, which increases the cost of production. Experiences from othersoybean countries suggests that, transgenic glyphosate-resistant soybean matched with broad-spectrumherbicide like glyphosate can control weeds in soybean fields effectively, Which can help with theconstruction of sustainable development farming system of crop rotation of soybean and corn. Theapplication and exploitation of above varieties and technology result in the the ascension of thecomprehensive production capacity and increase of competitiveness of the major soybean producingcountries in the American continents, which desserves China to learn from.In this thesis, the effect of the factors such as periods of application and dosage of glyphosate,weed control methods and tillage manners during the stage of seedling on the development, yield andeconomic benefits of glyphosate-resistant soybean was researched taking glyphosate-resistant soybeanlines698as material. Then cultivation technology was integrated and assembled. The results are asfollows:1The experimental results of four dosages of41%Roundup (2250,3000,3750,6000ml hm^-2),artificial weed control and three periods of application （the first compound leaf stage, the secondcompound leaf stage, the third trifoliolate leaf stage） showed that: Applying glyphosate before the thirdtrifoliolate leaf, there were no significant differences on effects of weed control with the dosage ofglyphosate increasing and delayed periods of application, and the stem control effect all reached99%.There was no phytotoxicity on soybean seedlings. The processing of soybean growth （R₁, R₃, R₇）was delayed but there was no significant differences, with the maximum deviation of R₁is0.6d, R₃is1d, R₇is1d. The yield (2014.5kg hm^-2) is the highest at the dosage of3000ml hm^-2during the period ofsecond compound leaf.2The results of influence on the weed control effect in soybean field, symptoms of herbicide injury,developmental process, yield components and economic benefits with five weed control methods（pre-emergence sealing treatment, post-emergence conventional processing of stems and leafs, treatmentwith manual processing, non-treatment） and four inter-tillage manners （loosen the soil deeplypost-emergence, twice of tillage, three times of tillage, no-tillage） indicated that: the difference wasextremely significant（P<0.01） among weed control effects of five weed control methods. The weedcontrol effect （97.3%） is the highest when treated with glyphosate. There was great difference inphytotoxicity. Pre-emergence treatment was Grade1, post-emergence treatment was Grade2, andtreatment of glyphosate was Grade0. There was no obvious difference in the developmental processesof soybean （R1, R7） under five weed control methods. The different weed control methods have someeffects on the yield components of soybean. The highest seed weight per plant and100-grain weight is31.2g and18.5g under the glyphosate treatment. The lowest seed weight per plant and hundred-seedweight is22.8g and17.3gwith non-treatment.3The effect of four inter-tillage （Seedlings after deep loosening,2times tillage,3times tillage,no-tillage） is different.The development of soybean is faster along with the times of tillage increasing.The time from germinate to first bloom （R₁） is27.3d, and time from germinate to physiologicalmaturity （R₇） is109.5d with three times of tillage.The height of bottom pod was lowered, and the plantheight, number of effective pods, number of seeds per plant, seeds weight per plant,100-seeds weight ofsoybean was increased when the inter-tillage times are getting more.4Among five different weed control methods and four tillage ways, treatment with glyphosate andthree times tillage were the most effective measures to the formation of soybean yield. Differences insoybean yield and economic benefits reached an extremely significant level （P <0.01）. Both the yield(2670.0kg hm^-2) and economic benefits (4027.50Yuan hm^-2) were the highest with treatment of glyphosate and three times of tillage.The results showed that, in the cold regions of Northeast China, the economic benefits in theglyphosate-resistant soybean field was optimal with the treatment of spraying t3000ml hm^-2of41%Roundup, weeding when the second trifoliolate leaf is expanded and conducting tillage for three timesduring the seedling stages.