Influences of herbicides, uprooting and use as cut flowers on sexual reproduction of Solidago canadensis

Solidago canadensis is a noxious invasive species in China. We examined the influences of herbicides on pollen germination and pollen tube growth and the effects of cutting flowers and herbicides on seed production and quality. We also determined the seed production and resource allocation to different organs of S. canadensis after uprooting the plants during their reproductive periods. The main results were as follows: (i) 49% pollen of S. canadensis was able to germinate on an appropriate medium; (ii) compared with paraquat, ethephon and 2,4-D, glyphosate had an ideal inhibitory effect on pollen germination and the formation of seeds of S. canadensis ; (3) cut flowering branches, when placed in water or nutrient solution, were still able to produce viable seeds; (4) resources were allocated more to the inflorescences to facilitate seed maturation after plants were uprooted at the flowering stage. Uprooted flower branches were still able to produce viable seeds, especially those in full flower. Therefore, in order to reduce the seed production of S. canadensis and spread of the species we suggest: (i) apply glyphosate at the flower bud stage, (ii) completely destroy uprooted plants at flowering stages and (iii) avoid using the flowering branches as ornamental materials.     

A direct-fired steam weeder

Flame weeders are a valuable weed management tool for organic growers and potentially for non-organic producers, if the number of registered herbicides continues to decrease. However, they have a number of problems including low-energy efficiency, fire risk and reduced performance in windy conditions. Steam has been shown to be a superior means of heat transfer to weeds and therefore steam weeders should outperform flame weeders. However, producing sufficient quantities of steam on tractor-mounted equipment has been problematic, because the standard designs of pressurised steam boilers are ill-suited for agricultural use. The 'direct-fired steam' weeder described here, is considered to resolve this problem, by spraying water as a fine mist directly into hot exhaust gases from a burner, causing it to evaporate quickly, thus negating the needs for a pressurised system. This design is diesel powered, but could also be run on renewable fuels such as vegetable oil, addressing concerns about the use of non-renewable 'fossil fuels' for thermal weeding. This approach is considered both effective in terms of steam generation and sufficiently practical and low enough in inherent risk for agricultural use. Production of commercial steam weeders based on this concept has commenced in New Zealand.     

组合梳齿式株间除草机构优化试验

设计了一种适合玉米和大豆作物株间作业的组合梳齿式除草机构,为优化该机构的设计并确定其关键参数的最优组合,利用正交试验方法对试验数据进行处理,通过极差分析,确定了除草部件工作参数对株间除草率和伤苗率的影响程度,优化出最佳工作参数组合。试验结果表明,梳齿数目和梳齿盘转速对株间除草机构的性能影响显著。最佳优化方案:梳齿数目6、梳齿间距50mm、梳齿盘转速180r/min 和作业速度2.3m/s,该条件下苗间除草装置的伤苗率为2.73%、苗间除草率可达87.6%。研究结果为设计性能可靠的株间除草机构提供了理论依据。      

“果尔”除草剂对杨树苗木影响及除草效果研究

"果尔"除草剂是一种高效、低毒、低残留的新型化学除草剂,为了筛选适合杨树苗圃中应用的"果尔"除草剂的浓度,研究了3.6、2.4、1.2 ml·L^-1的24%果尔乳油除草剂对渤丰3号杨生长的影响及除草效果。结果表明:渤丰3号杨对"果尔"较为敏感,较高施药浓度(3.6 ml·L^-1)会影响苗木的正常生长及光合速率和蒸腾速率,但对气孔导度和胞间二氧化碳浓度无显著影响。3.6 ml·L^-1的校正防效系数高达96.2%,除草效果最好;2.4 ml·L^-1除草效果次之,校正防效系数为81%,从保护杨树幼苗的角度出发,建议采用2.4 ml·L^-1的施药浓度。     

曲面轮齿斜置式稻田行间除草装置设计与试验

针对东北地区稻田行间除草装置存在除草率低、易伤苗等问题,设计一种曲面轮齿斜置式稻田行间除草装置.通过对除草轮作业时轮齿入土压埋过程和出土脱附过程进行力学分析,建立了土壤颗粒在除草轮齿上的相应力学模型,研究了轮齿结构对作业性能的影响;通过理论分析确定了影响除草性能的除草轮主要结构参数和各参数的取值范围,并设计了单铰链结构...     

倒V型稻田株间除草装置虚拟仿真及验证

针对现有稻田株间除草装置除草率低、伤苗率高的问题,对已设计的倒V型稻田株间除草装置进行有限元虚拟仿真。采用ALE多物质单元体算法建立土壤—水耦合模型,运用罚函数法,对除草爪与土壤—水模型进行流固耦合。采用二次正交旋转组合试验设计方法选取机器前进速度、除草爪转速与水层厚度进行虚拟仿真试验与分析,得到各因素及其一级交互作用对除草爪与土壤—水模型扰动率的影响规律,影响扰动率因素为除草爪转速>水层厚度>机器前进速度。通过对虚拟仿真试验结果进行优化设计,得到倒V型株间除草装置最佳因素参数组合为机器前进速度为0.53 m/s,除草爪转速为180 r/min,水层厚度为0.01 m。通过对仿真优化设计结果室内试验验证可知,倒V型稻田株间除草装置在最佳因素参数组合下进行除草作业平均除草率85.04%、平均伤苗率3.62%,满足稻田机械株间除草农艺要求。     

八爪除草机构的设计与实验-基于虚拟样机技术

为了实现田间株间精确机械除草,设计了一种八爪式智能除草机构,并重点研究了在实现不同株距株间除草时所需的前进速度和转速,进行了ADAMS动力学仿真实验和土槽中的物理样机实验.仿真和实验结果表明:该结构的设计能使工作爪端的割刀伸入株间进行除草,仿真实验中的割刀中心轨迹能够有效完成株间除草,并在样机试验中得到了验证.     

几种药剂防除直播稻田水三棱草初探

[目的]探讨几种药剂防除直播稻田水三棱草的效果。[方法]设计克草绅、灭草松、克草绅+灭草松3种组合防除直播稻田水三棱草。试验期间正常管理。[结果]在直播稻田水稻5叶期后,采用10%克草绅450g/hm2可有效防除6叶期以下的水三棱草,14d后株防效为91.64%,21d后株防效为86.21%,鲜重防效为94.72%。[结论]10%克草绅可以作为在江苏省淮安地区水稻5叶期后防除水三棱草的药剂值得大量推广。     

转G2_EPSPS和GAT基因大豆栽培地生存竞争能力以及对节肢动物多样性的影响

转基因作物的全球快速发展,其对环境的安全性影响成为人们关注的热点。我国转基因大豆的发展还处于试验研究阶段,对转基因大豆环境安全性进行科学严谨评价是我国转基因大豆商业发展的有力支撑,具有非常重要的理论和实践生产意义。本研究以转G2_EPSPS和GAT双价基因抗草甘膦大豆材料GE-J16与受体材料Jack以及当地主栽品种中黄37为研究对象。采用田间栽培试验,比较其生长时期的竞争能力以及成熟期繁育和生存能力的差异,研究了转基因和非转基因大豆栽培环境生存竞争安全性;连续3年调查供试大豆品种田间节肢动物的种类与数量,分析其多样性指数、优势集中性指数、均匀性指数的动态变化,明确转基因和非转基大豆以及草甘膦除草剂对豆田节肢动物群落多样性的影响。试验结果显示,不同生育时期的3个大豆品种的株高、复叶数、田间覆盖度、繁育系数和落粒性都基本一致无差异显著性,无栽培地生存竞争优势;转基因大豆GE-J16人工除草、转基因大豆GE-J16喷施草甘膦和非转基因大豆Jack人工除草三个处理3年的节肢动物的多样性指数、均匀性指数、优势集中性指数变化趋势一致,且3个处理同一生育时期之间各指标无显著性差异,说明耐草甘膦转基因大豆以及草甘膦除草剂并不会引起豆田节肢动物群落多样性的明显变化。     

基于机器视觉的株间机械除草装置的作物识别与定位方法

株间机械除草技术可进一步减少化学除草剂的使用,有利于环境保护和农业可持续发展.为实现智能化的株间机械除草装置自主避让作物并进入株间区域,该研究提出了一种株间机械除草装置的作物识别与定位方法.利用2G-R-B方法将作物RGB彩色图像进行灰度化,再选用Ostu法二值化、连续腐蚀和连续膨胀等方法对图像进行了初步处理.根据行像素累加曲线和曲线的标准偏差扫描线获得作物行区域信息,以作物行区域为处理对象,利用列像素累加曲线、曲线标准偏差和正弦波曲线拟合识别出作物,并结合二值图像中绿色植物连通域的质心获得作物位置信息.试验结果表明,该方法可以正确识别出作物并提供准确的定位信息,能适应不同天气状况、不同种类的作物,棉苗正确识别率为95.8%,生菜苗正确识别率为100%,该方法为株间机械除草装置避苗和除草自动控制提供了基本条件.