依据干扰理论优化入侵植物控制体系的研究进展

入侵植物控制行为可被视为对生态系统的干扰,因而以成熟的干扰理论指导入侵植物控制体系的构建,可为提高控制入侵植物的效率提供参考。文章对构成控制体系的6个技术因子(包括类型、频次、时令、强度、面积和程度等)进行分析,并对优化目标和优化方法进行综述。最后,提出了依据干扰理论构建入侵植物控制体系的步骤。     

Interactions of fungicide-herbicide combinations against plant pathogens and weeds

The fungicide cyproconazole and four herbicides, DNOC, dicamba, ioxynil and bromoxynil, were tested singly and in mixtures against Rhizoctonia cerealis (in vitro and on wheat) and against Pseudocercosporella herpotrichoides (in vitro, as well as against two weeds, Avena fatua and Sinapis alba. Cyproconazole showed very strong fungicidal acitivity against both fungi. DNOC was inhibitory to the fungi in vitro but had little effect on the disease; dicamba had low activity against the fungi in vitro but prevented the disease on wheat. Ioxynol and bromoxynil were moderately fungitoxic both in vitro and against the disease. Cyproconazole-herbicide mixtures were synergistic in their action against both fungi in vitro and against the disease. The level of synergism depended on the relative proportion of fungicide and herbicide components in the mixtures. Mixtures of herbicides with cyproconazole against weeds were at best additive in their activity.     

Effects of soil solarization on soil-borne populations ofPythium aphanidermatum andFusarium solani and on the potato crop in Tunisia

Summary Soil solarization by mulching with polyethylene for 60 days during summer in Tunisia, was effective in reducing dramatically to a depth of 30 cm inoculum levels ofFusarium solani (Fs) from 3,000 to 450 propagules gram⁻¹ of dry soil. Population densities ofPythium aphanidermatum (Pa) were reduced from 1,700 and 3,000 to 0.5 and 1 propagule gram⁻¹ of dry soil in the top 15 cm and at 1–30 cm depth, respectively. After a subsequent autumn potato crop, populations ofPa remained very low in the previously solarized soil whereas propagule density in non-solarized soils was similar to the initial density. Also, inoculum level ofFs increased by 40% in nonsolarized soils while it remained unchanged in solarized soils, suggesting microbial processes that prevented soil reinfestation. All the annual weeds were eradicated by solar heating but not the perennial weedConvolvulus arvensis. Potato plant growth and yields were improved in solarized plots.     

入侵杂草小飞蓬和钻形紫菀种子风传扩散生物学特性研究

种子的风传扩散是菊科入侵杂草的主要扩散方式之一,植物自身的传播特性和外在环境因子决定了种子扩散格局。从种子释放高度、沉降速度、脱落行为等内在因子出发,研究了两种在我国广泛分布的典型菊科入侵种小飞蓬和钻形紫菀自身的传播特性与风传扩散特征的关系。结果表明,小飞蓬和钻形紫菀的沉降速度均较小,分别为41.4cm·s-1和30.7cm·s-1,在空中停留时间长,且种子的脱落方式为非随机脱落,脱落概率大致与风速的平方成正比;种子的释放高度在种群内部存在很大的差异,显著影响种子的扩散距离。相比而言,小飞蓬种子的沉降速度大、释放高度高、远距离扩散（〉100m）的概率大,扩散距离更远。研究表明了植物自身的传播特性对种子风传扩散的重要性,也为其他菊科入侵杂草种子风传扩散的研究提供了科学依据。     

Effects of repeated clover undersowing,green manure ley and weed harrowing on weeds and yields in organic cereals

Abstract

Cover crops can be used to reduce leaching and erosion, introduce variability into crop rotation and fix nitrogen (N) for use by the main crops, less is however known about effects on weeds. The effects on weed seed bank, weed growth and grain yield of 4 years of annual undersown clover and ryegrass alone and in combination, and one of the 4 years with clover or clover + grass as green manure, were studied in oat and spring wheat at two experimental sites in south-eastern Norway. These treatments were compared with no undersown crop (control) and with weed harrowing. In contrast to many results in the literature, the undersown clover in this study did not suppress annual weeds, but fertilized the weeds as well as the cereals. Undersown clover resulted in a statistically significant increase of grain yield at the two sites to 116% and 121% of control. During the 4-year period relative seed bank and density of emerged weed (dominated by Spergula arvensis) increased significantly about 4.5 and 10 times respectively in the undersown clover plots at Apelsvoll. At Kise both ryegrass alone and ryegrass mixed with clover significantly suppressed the weed biomass to 70% and 74% of control respectively. It is concluded that fertilization effects of undersown clover may have dominated and overriden the competitive effects. One whole-season clover green manure did not increase the mean yield, but resulted in a significant drop in seed bank size the following year, because of limited weed establishment in an established ley. Only a slight increase in average weed biomass was observed at one of the two experimental sites. The weed seed bank and the weed biomass were essentially kept at steady state during the experimental period in harrowed plots, but harrowing decreased grain yield significantly at both sites.     

拜田净防治稻田杂草试验效果

为明确拜田净对水田杂草的防治效果,在田间采用大区对比法进行药效试验。结果表明,拜田净50%可湿性粉剂300g/hm2+草克星10%可湿性粉剂225g/hm2,在水稻移栽田一次性施用,对禾本科杂草防效100%,对阔叶杂草防效93%,对水稻不但安全,而且使水稻分蘖多、无效分蘖少、生长快,增产显著。比禾大壮+草克星或丁草胺+草克星效果好。     

福建地区直播稻田禾本科杂草防控药剂及其使用浓度筛选

为有效控制福建地区直播稻田禾本科杂草的危害,以莆田市仙游县游洋乡的水稻种植基地为试验点,选择测定1%噁嗪草酮悬浮剂、10%双草醚悬浮剂和20%氰氟草酯油悬浮剂等3种除草剂对稗草、千金子等禾本科杂草的防治效果,筛选确定最佳除草剂及其理想的田间使用浓度。结果表明:20%氰氟草酯油悬浮剂是防治直播稻田中稗草、千金子等禾本科杂草最佳的除草剂,田间推荐使用浓度为45~105g·hm-2(有效成分)兑水675L·hm-2,药后30d防治效果达均可80.00%以上,无药害产生,对水稻安全。     

内蒙古牙克石市油菜高产栽培技术

油菜是牙克石市主要栽培的作物,提高油菜的产量和品质对促进当地农业的发展和提高人们的生活水平有着重要的作用。经过多年的生产实践和实地调查,并参考国内相关的文献资料,加以整理分析,提出了油菜高产栽培技术。应尽量选择夏翻地播种油菜;如选择春秋翻地播种,首先要保证有足够底墒、杂草基数低、整地质量好的地块。选择青杂2号、青杂3号、青杂5号等优良的品种并进行清选和药剂处理;提出了适宜的播种期和最佳密度,合理的肥料配方;田间科学管理措施,病虫草害的综合防治技术等成套的综合高产栽培技术。此项技术经过在生产上应用,表现出油菜前期长势好、病虫害轻,产量和品质都有明显的提高,获得了较好的效果。     

Field response of Lathyrus cicera germplasm to crenate broomrape (Orobanche crenata)

Crenate broomrape (Orobanche crenata Forks.) is a major constraint for grain and forage legume cultivation in Mediterranean agriculture, to which little resistance is available. We studied the response to O. crenata of a germplasm collection of chickling pea (Lathyrus cicera L.) in field trials over two seasons showing that resistance although scarce and masked by confounding factors, is available and can be used in breeding. The level of infection was highly influenced by environmental factors and plant growth cycle. Earlier accessions were less infected due to competition of the earlier settled pods with O. crenata tubercles. O. crenata infection strongly reduced host biomass and grain yield. Deviations from the polynomic regression gave an improved approximation of the true genetic resistance levels present in the germplasm.     

敌敌畏毒土防治鼠妇的室内毒力试验

[目的]测定敌敌畏毒土防治鼠妇的毒力效果。[方法]将80%的敌敌畏乳油按100、200、400、800和1 000倍五个配比配成毒土,测定其室内对普通球鼠妇的杀虫效果,利用SPSS统计分析出其LC50值。[结果]室内实验表明,随敌敌畏毒土配比的增高,即随敌敌畏乳油含量的下降,普通球鼠妇的平均死亡率明显降低,毒土配比为100倍,试虫平均死亡率为98.9%;毒土配比为200倍、400倍、800和1 000倍时,试虫平均死亡率为81.1%、73.3%、40.0%、33.3%。[结论]通过不同毒土配比的差异比较,表明400×毒土比较适合生产应用,80%敌敌畏乳油毒土配比的LC50为642.10倍。关键词毒力效果;敌敌畏毒土;鼠妇;防治