共查询到20条相似文献,搜索用时 15 毫秒
1.
抗药性杂草种群的发展及其防治对策 总被引:25,自引:1,他引:24
叙述了全球抗药性杂草种群的分布及其发展动态,杂草抗药性的原因和抗性杂草种群对作物的危害,提出了以作物轮作,栽培,来茬等农业措施为主,结合生态防治,生物防治和合理使用除草剂来治理抗性杂草,延缓杂草产生抗性的综合防治对策。 相似文献
2.
L. J. Wiles 《Precision Agriculture》2009,10(3):277-290
Site-specific weed management can include both limiting herbicide application to areas of the field where weed pressure is
above the economic threshold (patch spraying) and varying the choice of herbicide for most cost-effective weed control of
local populations. The benefits of patch spraying with several, postemergence herbicides in irrigated corn were evaluated
in simulation studies using weed counts from 16 fields. Patch spraying with one, two or the number of herbicides that maximized
net return for a field was simulated. With patch spraying of one herbicide, the average area of a field left untreated is
34.5%. Net return increases by $3.09 ha−1 compared to a uniform application without decreasing crop yield. Additional herbicides increase the average benefits with
just 4% more of the field treated. With two herbicides, the increase in net return is almost tripled and herbicide use is
reduced nearly 10-fold compared to patch spraying with one herbicide, and weed control is better than the uniform application
in 10 fields. Using more than two herbicides for patch spraying further reduces weed escapes, but herbicide use is greater
than a uniform application in 10 fields. Growers might be more willing to adopt patch spraying if more than one herbicide
is used in a field. 相似文献
3.
对PC–B型带传动试验台进行改进:将主电机的传动轮改成切割装置,安装试验台架及夹持装置,更换更精确的压力传感器,研制出杂草切割试验台,以蒿草、狗尾草和牛筋草为材料,通过切割试验,确定杂草直径、含水率、电机转速、削切角对切割阻力的影响。结果表明,杂草切割阻力与电机转速平方成反比,与杂草直径平方成正比,与削切角平方成反比;不同杂草含水率对切割阻力影响不同,蒿草与狗尾草切割阻力与含水率平方成反比,狗尾草反之。单因素试验中,蒿草直径3.5~4.5 mm,风干10 h,含水率33.54%时,最大切割阻力为11.06 N。以蒿草为材料的正交试验结果表明,直径、含水率、削切角和电机转速依次影响切割阻力。Spss软件分析表明,在风干含水率48.53%、削切角60°、直径最大组(3.5~4.5 mm)、电机转速为最低切断转速1.2倍时为最优组合。 相似文献
4.
大荔县是陕西省棉花主产区,1992~1995年棉铃虫曾超常大发生,农药使用频次高,棉铃虫对常用农药产生了一定的抗药性,致使防治困难.1995年我站作为农业部棉铃虫抗药性监测点,开始监测棉铃虫对有机磷(久效磷)、拟除虫菊酯(氯氰菊酯)、氨基甲酸酯(灭多威、万灵)等三大类常用农药的抗性发展规律,边监测边进行综合治理,取得较好效果.近两年全县推广种植了抗虫棉,棉田棉铃虫发生特点有了新变化,就目前抗虫棉田棉铃虫对三大类农药抗性发展状况,调整了以往的防治思路,提出今后一个时期内的治理对策. 相似文献
5.
6.
浅谈读者投诉及投诉管理策略 总被引:1,自引:0,他引:1
冯世华 《农业图书情报学刊》2010,22(7):286-287,306
图书馆的流通窗口一直是读者投诉的焦点,对此图书馆应积极面对,查原因找差距,及时向读者反馈意见;同时还要采取措施,提高服务质量。 相似文献
7.
Rural families must constantly negotiate their livelihoods by obtaining access to natural resources, labor, capital, knowledge,
and markets. Successful negotiation leads to enhanced family well-being and sustainable use of natural resources. Unsuccessful
negotiation threatens family survival, threatens sustainable use of natural resources, and reduces bio-diversity. These negotiation
processes are mediated by gender relations. The ideas of negotiation and of survival strategies outlined here provide a framework
within which the articles of this issue can be situated. The articles are the result of research on gender and natural resource
management conducted in Latin America, Asia, Africa, and North America. Each experience illustrates the consequences for natural
resources and family well being when they have voice and when they do not have voice in household decisions.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
Stephen E. Gareau 《Agriculture and Human Values》2004,21(4):347-353
During times of economic uncertainty, such as the current period, all costs of agricultural production become important and worthy of close scrutiny if the threat of farm foreclosures is to be minimized. This concern particularly applies to the cost of plant nutrients, which, under conventional approaches, typically represents 24%–30% (or more) of the total variable costs of production [Lu et al. (2000) Food Reviews International 16(2): 121–157; Bullen and Brown (2001) Economic Evaluation of UNR Cotton, NC State University, Raleigh, North Carolina]. The purpose of this paper is to examine, via a review of the literature, the economics and profitability of various plant nutrient management strategies–both conventional and alternative ones–in an attempt to identify those strategies that can lead to financial resource optimization and, ultimately, maximum profits for farm enterprises. The results of this analysis are as follows: In a meta-analysis of 120 studies, conventional nutrient management systems, using commercial fertilizers, showed higher profit for most grain crops (with the exception of corn and sorghum), than organic nutrient management systems. Both cover crop and animal manure-based systems show considerable promise as alternative nutrient management strategies for increasing farm profitability. A cover crop system produced the highest average corn yield and gross margin per hectare with the smallest coefficient of variation compared to no-tillage conventional, manure-based, or crownvetch systems. Manure-based systems that do not require purchase or transport of the manure (as in combined animal and crop production systems) can be considerably more profitable than conventional systems. Both manure-based and cover crop systems that do not include the use of commercial fertilizers (i.e., organic systems), hold particular promise due to the output price premiums typically garnered by the organic crops grown under such conditions. 相似文献
9.
The agricultural use of synthetic insecticides usually protects crops but imposes strong selection pressures that can result in the development of resistance. The most important resistance mechanisms are enhancement of the capacity to metabolically detoxify insecticides and alterations in target sites that prevent insecticides from binding to them. Insect control methods must incorporate strategies to minimize resistance development and preserve the utility of the insecticides. The most promising approach, integrated pest management, includes the use of chemical insecticides in combination with improved cultural and biologically based techniques. 相似文献
10.
深松耕作阻力的影响因素分析与减阻策略 总被引:1,自引:0,他引:1
【目的】识别深松耕作阻力的关键因素及其影响程度,为深松减阻技术与装备研究奠定基础。【方法】采用7因素3水平正交试验和单因变量方差分析方法,研究深松机铲形(箭形、凿形)、铲距(300,400,500mm)、入土角(18°,23°,28°)、土壤含水率(10%,15%,20%)、土壤坚实度(1 000,1 500,2 000kPa)、耕深(250,300,350mm)及牵引速度(2,3,4km/h)对深松耕作阻力的影响。【结果】铲形、铲距、入土角、土壤含水率、土壤坚实度、耕深、牵引速度的检验概率依次为0.613,0.057,0.056,0.495,0.013,0.001和0.797;不同因素对耕作阻力影响程度的排序为耕深土壤坚实度入土角铲距土壤含水率铲形牵引速度,且耕深、土壤坚实度、入土角、铲距对深松耕作阻力变化影响显著。【结论】为减小深松耕作阻力、提高耕作质量,建议在满足农艺要求的前提下,深松深度的确定应以"耕作层+犁底层"的厚度为主要依据;深松作业间隔年限的确定应将土壤坚实度作为重要评价指标;合理配置深松铲的入土角和铲距有助于减小深松作业阻力和提高作业质量。 相似文献
11.
Donnan CB 《Science (New York, N.Y.)》1991,251(4993):498
12.
13.
L.J. Wiles 《Computers and Electronics in Agriculture》2011,78(1):106-115
Mapping weed cover during the fallow period of dryland crop rotations would be valuable for weed management in subsequent crops and could be done with low cost color digital cameras, however most managers lack the specialized software and expertise needed to create a map from the images. A system of software was developed to quantify weed cover in fallow fields in digital images and to simplify and automate the most challenging tasks that non-GIS professionals confront in creating and using maps derived from a large number of images. A GIS file of image locations is created with inexpensive consumer software. Images are classified, a GIS file is generated and the map is displayed in a simple GIS viewer with free software we developed. A map can be generated from 1000 images and 5000 GPS coordinates in 30 min, including image classification. The classified and original images for all locations can be viewed together easily from the map application. The accuracy of estimating weed cover was evaluated using images collected in 15 fields under natural light with a consumer grade camera mounted on an ATV driving 8-11 km h−1. Weed cover was estimated with 96% accuracy for images, regardless of the amount of crop residue, unless part of the image was shaded by the camera. In those images, accuracy was 90% or better. This system will work with many professional and consumer digital cameras and GPS units and the classification algorithm can be easily modified for other applications. 相似文献
14.
15.
16.
许海萍 《福建农业大学学报(哲学社会科学版)》2011,(6):102-105
从高校专利管理入手,分析高校专利方面存在的问题,学习国外高校的先进经验,提出高校专利管理的若干对策:(1)创新管理方法,促进高校专利的可持续发展;(2)增加经费投入,强化高校专利的有效保护;(3)完善奖励机制,激发教职工发明创造的积极性;(4)加快成果转化,促进高校专利的良性循环。 相似文献
17.
18.
秸秆还田与氮肥管理对稻田杂草群落和水稻产量的影响 总被引:1,自引:1,他引:0
为了研究秸秆还田和氮肥管理对稻油轮作夏季稻田杂草群落分布特征和水稻产量的影响,试验设5个处理:常规施肥NPK+秸秆不还田,N基追肥比例为6:2:2(F0NS,CK);常规施肥NPK+秸秆全量还田,N基追肥比例为6:2:2(F0S);常规施肥NPK+秸秆全量还田+秸秆腐解剂,N基追肥比例为6:2:2(F0SA);常规施肥NPK+秸秆全量还田+秸秆腐解剂,N基追肥比例为7:2:1(F1SA);常规施肥PK,N减量15%+秸秆全量还田+秸秆腐解剂,N基追肥比例为6:2:2(F2SA)。记录杂草种类、数量、密度、生物量等指标,并于2016年9月底进行水稻实收测产。结果表明,与CK相比,F0S、F0SA、F1SA和F2SA处理的杂草总密度分别降低50.3%、29.2%、20.3%和6.8%,秸秆还田可以有效降低稻田杂草密度、生物量和杂草多样性;与F0S相比,F0SA、F1SA和F2SA处理的杂草发生数量和发生密度差异不显著,但禾本科和莎草科杂草不同程度地减少,柳叶菜科和玄参科杂草显著增加,配施秸秆腐解剂对农田杂草种类影响显著。在秸秆腐解剂和不同施氮措施下,与F0SA相比,F1SA和F2SA处理杂草种类、生物量增加,杂草相对密度降低,但差异不显著;各处理间优势杂草种类和种群数量减少,但F2SA处理下生物多样性指数明显高于F0SA和F1SA处理。与CK相比,F0S、F0SA、F1SA和F2SA处理的水稻产量分别提高7.13%、16.55%、17.80%和10.67%,其中F1SA处理作物产量增幅最高。研究表明,秸秆还田和氮肥管理能有效降低稻田杂草的发生密度、总生物量和和生物多样性,有利于提高水稻产量。 相似文献
19.
An on-farm approach to quantify yield variation and to derive decision rules for site-specific weed management 总被引:2,自引:1,他引:1
C. Ritter D. Dicke M. Weis H. Oebel H. P. Piepho A. Büchse R. Gerhards 《Precision Agriculture》2008,9(3):133-146
Grain yield often varies within agricultural fields as a result of the variation in soil characteristics, competition from
weeds, management practices and their causal interactions. To implement appropriate management decisions, yield variability
needs to be explained and quantified. A new experimental design was established and tested in a field experiment to detect
yield variation in relation to the variation in soil quality, the heterogeneity of weed distribution and weed control within
a field. Weed seedling distribution and density, apparent soil electrical conductivity (ECa) and grain yield were recorded and mapped in a 3.5 ha winter wheat field during 2005 and 2006. A linear mixed model with
an anisotropic spatial correlation structure was used to estimate the effect of soil characteristics, weed competition and
herbicide treatment on crop yield. The results showed that all properties had a strong effect on grain yield. By adding herbicide
costs and current grain price into the model, thresholds of weed density were derived for site-specific weed control. This
experimental approach enables the variation of yield within agricultural fields to be explained, and an understanding of the
effects on yield of the factors that affect it and their causal interactions to be gained. The approach can be applied to
improve decision algorithms for the patch spraying of weeds. 相似文献