3种农药对蔗田杂草香附子的防除效果及其安全性评价

研究旨在明确75%氯吡嘧磺隆WDG、25%硝磺·莠去津OD和73%甲·灭·敌草隆WP等对蔗田香附子的防除效果及其安全性。采用田间试验方法,分别调查了喷施不同药剂处理的甘蔗和香附子的叶色变化情况,香附子地表植株、根和地下球茎（或芽）的死亡率。结果表明,75%氯吡嘧磺隆WDG对香附子地上部分、根和地下球茎（或芽）防效均达90%以上且对甘蔗安全;73%甲·灭·敌草隆WP可有效控制香附子地表植株和根,但对地下球茎（或芽）防效较低;25%硝磺·莠去津OD仅能使香附子地表植株变色,对香附子根和地下球茎（或芽）几乎无效。75%氯吡嘧磺隆WDG对香附子防治效果好且对甘蔗安全,可作为蔗田香附子防治的轮换药剂,使用剂量以90、135 g/hm²为宜。     

定量泵负载敏感系统卸荷压力冲击抑制研究

定量泵负载敏感系统在快速卸荷时容易出现压力冲击现象,对系统的可靠性和寿命产生较大危害。三通压力补偿阀是定量泵负载敏感系统中关键的调压元件,本文以三通压力补偿阀为切入点,建立定量泵负载敏感系统功率键合图模型,基于键合图模型推导系统的状态方程,建立Matlab动态仿真模型,探讨系统卸荷压力冲击的抑制方案。基于系统仿真模型,首先对系统卸荷压力冲击的仿真与试验进行对比,验证了仿真模型的正确性;然后,针对三通压力补偿阀的系统压力腔阻尼、阀芯直径、Ls腔阻尼、阀口锥角等关键参数,对卸荷压力冲击影响规律进行仿真;最后,基于关键参数对卸荷压力冲击影响规律的分析,提出了一种"小阀芯、双阀口"型三通压力补偿阀结构优化方案,并对其卸压冲击抑制效果进行了仿真和试验。结果表明,该方案可以有效抑制卸荷压力冲击,优化后系统卸压冲击压差比原系统降低了89%,卸荷压力降低了20%,进一步实现了节能。     

11种除草剂对秋播豌豆生长发育的影响及防效研究

化学除草剂已成为农田控制杂草的重要技术措施，但目前还没有针对豌豆田杂草的高效、安全除草剂。为此，本文以陕西省关中地区主栽品种‘西豌2号’为试验材料，采用6种苗前除草剂（48%氟乐灵乳油、50%乙草胺乳油、33%二甲戊灵乳油、96%精异丙甲草胺乳油、50%敌草胺水分散粒剂、40%扑草净可湿性粉剂）和5种苗后除草剂（15%精吡氟禾草灵乳油、10%精喹禾灵乳油、12.5%烯禾啶乳油、10.8%高效氟吡甲禾灵乳油、12%烯草酮乳油）处理，设清水喷施（CK1）和人工除草（CK2）为对照，调查秋豌豆田杂草种类，研究不同除草剂的防除效果，探讨各除草剂对秋豌豆生育进程、形态特征、经济效益等相关指标的影响。结果表明：1）研究区秋豌豆田杂草共7科13种，以阔叶类杂草为主，其中阔叶杂草9种。除草剂对杂草株数和鲜重均有不同程度的防效作用，苗前除草剂以33%二甲戊灵综合防效最佳，苗后除草剂以12%烯草酮综合防效最佳。2）自越冬期至开花期，各除草剂均对秋豌豆株高、叶绿素相对含量产生显著影响，但从始荚期开始，影响不再显著。不同种类的除草剂对秋豌豆根、茎、叶器官各时期干物质的积累量均有不同程度的抑制作用，各处理的秋豌豆茎、叶器官干物质的移动率及转运率均高于人工除草，叶器官干物质的移动率及转运率均高于茎器官。3）除草剂对百粒重、荚长等产量构成因素影响不显著，除10.8%高效氟吡甲禾灵导致产量略微下降之外，其他除草剂均表现出一定的增产作用，其中33%二甲戊灵、12%烯草酮可使秋豌豆增产25%以上。所有除草剂处理的净收入均有所增加，以33%二甲戊灵、12%烯草酮处理的净收入为同时期除草剂中最高。由此可见，除草剂的使用有助于种植者经济效益的提高，结合各除草剂的防除效果、安全性、经济效益，苗前除草剂33%二甲戊灵和苗后除草剂12%烯草酮在秋豌豆田的综合效应分别为同时期除草剂中最佳。本试验条件下，针对秋豌豆田，苗前除草剂推荐使用33%二甲戊灵，苗后除草剂推荐使用12%烯草酮。     

Four years validation of decision support optimising herbicide dose in cereals under Spanish conditions

The Danish decision support system Crop Protection Online (CPO) optimises herbicide weed control. CPO recommends specific herbicide solutions to achieve a required level of control. The aim is to apply herbicides as little as possible but as much as necessary. CPOWeeds is a version of CPO adjusted to conditions in North-eastern Spain. The predicted efficacies and the yield obtained with CPOWeeds were validated in winter cereal field trials from 2010 to 2013. All CPOWeeds treatments were related to the efficacies obtained with standard herbicide treatments decided upon by local advisors. The predictions from CPOWeeds were compared to the actually achieved efficacies in the field trials for the nine weed species at different developmental stages and for 84.2% of the comparisons the obtained efficacies were equal to or higher than predicted. The average difference between predicted and observed efficacies was 2.35 percentage points. Yield was measured in three trials and the recommendations from CPOWeeds were maintaining yield. There were two situations where CPOWeeds were performing suboptimal. One is in the early weed growth stages, as the model is not yet prepared to account for water stress on root action herbicides applied at 10-11 BBCH. The second situation was in fields with a prior unidentified population of resistant Alopecurus myosuroides. For key species in winter cereals in Spain, such as Avena sterilis, Lolium rigidum and Papaver rhoeas, CPOWeeds achieved a satisfactory control level. It was concluded that the use of CPOWeeds allowed optimisation of the herbicide application with a very high robustness. The recommendations were satisfactorily for the conditions of the Northeast of Spain and have the potential to decrease the amount of applied herbicides by at least 30%. Therefore, it can be an important tool in Integrated Weed Management.     

Effect of herbicide application on weed flora under conservation agriculture in Zimbabwe

Increased challenges of weed control in the smallholder farming sector of southern Africa have often resulted in small yields. The objective of this study was to evaluate the effects of different weed control strategies on weed flora and composition under conservation agriculture (CA) systems in Zimbabwe. This study was conducted at three on-station trial sites namely Domboshawa Training Centre (DTC), University of Zimbabwe farm (UZ farm) and Henderson Research Station (HRS) in a maize–soybean rotation for four seasons from 2009–2010 to 2012–2013 seasons. Hand weeding was done whenever weeds were 10 cm tall or 10 cm in circumference for weeds with a stoloniferous growth habit. Weed identification was done up to the weed species level, and the Shannon–Weiner diversity and evenness index was used to determine the response of weed flora to herbicides. Results showed that there were more weeds in the early years which decreased gradually until the final season. Weed species diversity was not affected by herbicide application and the results indicated that weed species diversity was small in CA systems. Annual weed species constituted a greater proportion of species, and species richness decreased with the duration of the study. Richardia scabra L. and Galinsoga parviflora Cav. were the most common dominant weed species at all sites and in all seasons. Moreover, herbicide application had no effect on the evenness of weeds in the plots but site characteristics had a significant effect on the distribution of weed species (weed species evenness). The results presented in this study suggest that herbicide application facilitates a depletion of weed seed bank/number of weeds over time. Thus, herbicide application in CA has potential to reduce weed density, species richness and species diversity in the long term which may lead to more labour savings and larger yields.     

2种除草剂对燕麦产量、杂草防除及后茬作物安全性的影响

试验采用前期筛选的2种最佳除草剂仲丁灵和二甲·辛酰溴施用于燕麦田(Avena sativa),调查燕麦鲜草、种子产量及防效,并初步研究不同浓度除草剂对后茬植物出苗率、株高及鲜重的影响。结果表明:药后15 d,30 d株防效及鲜重防效表现为施用高浓度二甲·辛酰溴中浓度二甲·辛酰溴高浓度仲丁灵。表明与对照相比,所有处理对燕麦产量均有增产作用,2种除草剂都在中浓度增效明显,且二甲·辛酰溴优于仲丁灵。低浓度除草剂处理过的土壤对后茬冬油菜及皮、裸燕麦出苗无影响,在中、低浓度下对后茬成株期株高和鲜重有促进作用,而高浓度除草剂对后茬出苗率及成株期生长有抑制作用。仲丁灵中浓度对后茬影响最小,高浓度二甲·辛酰溴对后茬抑制最大。因此建议燕麦田施用40%仲丁灵和40%二甲·辛酰溴分别不超过5625和2025 mL·hm~(-2)。     

森林重泡沫施用技术的研究

本文描述了在林缘草地施用森林重泡沫灭火剂技术，同时介绍了森林重泡沫灭火剂的质量问题，该剂的特点是稳定性好，抗风力强，并一具有良好的附着力，渗透性和抗烧性。     

330 g/L二甲戊灵乳油防除韭菜田杂草试验

为了确定330 g/L二甲戊灵EC能安全有效控制韭菜田杂草的用量,采用播后苗期施药,研究其在施后15、30、45 d对韭菜田旱稗、马唐等杂草的防治效果。试验结果表明,药后45 d,试验药剂495~742.5 g/hm2(有效成分用量)对旱稗、马唐、狗尾草、野苋、藜的最终株防效和鲜质量防效分别为96.97%~99.95%、97.86%~99.95%,96.46%~100%、96.78%~100%,92.51%~98.91%、94.06%~98.88%,54.51%~70.30%、58.69%~77.29%,55.82%~68.72%、72.64%~82.78%。药后10~30 d观察结果表明,试验药剂处理土壤对韭菜安全。     

Vegetation dynamics in burnt heather-gorse shrublands under different grazing management with sheep and goats

Vegetation dynamics in previously burnt shrublands dominated by gorse (Ulex gallii) in north-west Spain were studied during 4 years under different grazing managements with sheep (Gallega breed) and goats (Cashmere or local breed). Initially (Period 1), treatments consisted of sheep or goat grazing on four plots (two replicates). After two grazing seasons, the plots were split in two and the treatments were reversed in four of the subplots; sheep were placed in subplots previously grazed by goats and vice versa (Period 2). The results from Period 1 showed that goats control the regrowth of gorse (from 19.6 to 14.2% of cover) more effectively than sheep (17.8 to 27.0% cover; P < 0.05), favouring the increase in herbaceous plants (from 21.5 to 42.1% of cover under goat grazing and from 22.1 to 26.6% under sheep grazing; P < 0.01). In Period 2, after changing treatments, there was a clear effect of the previous management (P < 0.01), conditioning the dynamics of the different plant components. Where the same animal species were maintained for 4 years, the differences between sheep or goat grazing on gorse and herbaceous plant dynamics increased (24.4% of gorse and 35.2% of herbaceous plant cover under goat grazing vs 43.8% of gorse cover and 19.1% of herbaceous plant cover under sheep grazing). Animal species change buffered the differences between sheep and goats during the second Period.