安徽省沿江植棉区春季直播棉田杂草防除措施研究

按照安徽省沿江植棉区春季直播棉田杂草发生规律，选用5种除草剂在棉花不同生长时期施用，结合中耕除草，研究这些除草措施对春季直播棉田杂草的防除效果；同时调查了不同除草措施对棉花生长、产量和纤维品质的影响。结果表明，播后芽前喷施土壤处理除草剂可较好地防治棉田主要禾本科杂草和小粒阔叶类杂草。苗期中耕除草的株防效与除草剂组合差异不显著，质量防效则低于除草剂组合；草甘膦+精喹禾灵+三氟啶磺隆组合的防效优于草甘膦+精喹禾灵组合，但两者差异不显著。蕾期喷施草甘膦+精喹禾灵+三氟啶磺隆的除草效果优于三氟啶磺隆+精喹禾灵。不同的除草措施对棉花生长、产量产生显著影响，对纤维品质影响不明显。推荐该地区春季直播棉田最佳除草措施为：播后芽前土壤处理除草剂+苗期中耕除草+蕾期茎叶处理除草剂。     

安徽省东至县油菜-棉花连作棉田杂草发生规律的研究

安徽省沿江植棉区以油菜-棉花连作为主。为进一步了解该种植模式下杂草群落结构及多样性变化,2013年对安徽省东至县棉田杂草发生情况进行了调查。结果表明阔叶杂草种类和数量均大于禾本科杂草,千金子、铁苋菜和婆婆纳已上升为优势种;前期不除草,到8月上中旬杂草在种类和数量达到最高,对棉花产量影响较大。     

杜邦豆威与禾耐斯混用防除大豆田杂草的研究

杂草是制约大豆高产稳产的主要因素之一。夏播大豆播种期值杂草出土生长高峰期 ,此时正是“三夏”大忙季节 ,劳动力紧张 ,人工除草天气炎热 ,劳动强度大 ,且杂草易复活和再生 ,极易形成草荒。因此 ,大豆田化学除草犹为重要。目前生产上应用的禾耐斯、乙草胺、都尔等对禾本科杂草防效较好 ,而对阔叶杂草的防效较差 ;杜邦豆威只对阔叶杂草有效 ,而对禾本科杂草无效。我地为以禾本科杂草为主以阔叶杂草为辅的杂草混发区 ,为了达到一次施药能够兼治禾木本科杂草和双子叶杂草的目的 ,特设计杜邦豆威与禾耐斯混用试验 ,现将试验结果报导如下。1　…     

大麻高效除草（封闭）技术研究

本文利用不同除草剂进行播后苗前（封闭）处理,对大麻生产期田间杂草综合防治效果进行了研究。研究结果表明：采用65％异丙甲草胺乳油3L／hm2封闭除草,对禾本科杂草防效可达55．6％。对阔叶杂草龙葵、藜、蓼、苋的防治效果分别达到66．7％、37．5％、88．9％、89．5％,对阔叶杂草蓼、苋防治效果比较理想：采用40％施田扑乳油3L／hm2封闭除草,对禾本科杂草防效可达63．9％,对阔叶杂草龙葵、藜、蓼、苋的防治效果分别达到75．0％、75．0％、66．7％、57．9％,阅叶杂草龙葵、藜比较理想。两种除草剂对禾本科杂草均较好的抑制生长效果。     

沿海农区麦田杂草防除技术研究

根据沿海农区麦田杂草发生危害现状 ,麦田杂草可分为禾本科和阔叶类 2大类 ,进行了硬草 (禾本科恶性杂草之一 )、泽漆 (新上升难治阔叶类杂草 )的发生危害规律和有关生物学特性的基础研究 ,重点研究了控制麦田硬草、泽漆的关键措施 ,明确了应用化学除草剂 (骠马、乙草胺、异丙隆、使它隆、苯磺隆及其复配剂 )的核心所在 ,结合其它有关专题研究结果 ,在先进的原则策略指导下 ,组装了沿海农区麦田杂草长效治理技术措施。     

棉田阔叶杂草发生危害与化除应用

1棉田主要阔叶类杂草及危害 棉田由于长期应用防除禾本科杂草的除草剂，导致阔叶类杂草的发生危害日趋严重，表现为种类多，分布广，生长力旺，单株覆盖面积大，与棉株大量争夺水分、养料、空间，致使棉株生长势弱，结铃数少而且小，直接影响棉花的产量和品质。阔叶类杂草的优势种在主要棉区之间有较大差别。     

除草剂混配施用对棉田常见杂草的防除效果

为了检验除草剂防除棉田杂草效果,以三氟啶磺隆、嘧草硫醚和精喹禾灵之间不同剂量的混配施用.试验表明：三氟啶磺隆和精喹禾灵两种混用及三氟啶磺隆、嘧草硫醚和精喹禾灵3种混用均对棉田杂草都有较好的防除效果.施药后7天杂草表现药害症状.施药后20天,三氟啶磺隆与精喹禾灵两种除草剂混用,随着三氟啶磺隆用量的增加对禾本科杂草的防效由89.2％增加到95.3％,对阔叶类杂草的防效由86.3％增加到94.9％,总体株防效由87.8％增加到95.2％;三氟啶磺隆与精喹禾灵、嘧草硫醚混剂3种除草剂混用,在精喹禾灵用量相同的条件下,增加三氟啶磺隆或嘧草硫醚的用量,对禾本科杂草、阔叶类杂草、杂草总体株防效均提高.施药后40天的株防效和鲜重防效均80％以上,说明混配药剂的持效期较长.     

沿海农区麦田杂草防除技术研究

根据沿海农区麦田杂草发生危害现状，麦田杂草可分为禾本科和阔叶类2大类，进行了硬草(禾本科恶性杂草之一)、泽漆(新上升难治阔叶类杂草)的发生危害规律和有关生物学特性的基础研究，重点研究了控制麦田硬草、泽漆的关键措施，明确了应用化学除草剂(骠马、乙草胺、异丙隆、使它隆、苯磺隆及其复配剂)的核心所在，结合其它有关专题研究结果，在先进的原则策略指导下，组装了沿海农区麦田杂草长效治理技术措施。     

甘蔗除草膜防除蔗地杂草试验

为更有效地防除蔗地杂草,在甘蔗下种后进行甘蔗除草膜防除蔗地杂草试验,结果表明：旱地蔗盖膜后60天内,除草膜对单双子叶杂草株防效达100%;水田蔗盖膜后90～110天,与普通地膜（CK1）比较,除草膜对单子叶杂草的株防效为：4.1%、2.7%和21.9%,对双子叶杂草的株防效为：83.5%、65.2%和52.5%。与露地模式（CK2）比较,除草膜对单子叶杂草的株防效为16.2%、-215%和-96.5%,对双子叶杂草的株防效分别为：97.4%、84.4%和89.2%。甘蔗除草膜在膜后90天内对杂草有较好的防除效果,但在长期连作、多年生恶性杂草种子库丰富的地块使用除草地膜,易造成杂草种类剧减而使杂草种群单一,诱发单一杂草的爆发,因此除草地膜的应用要有选择性。     

敌草隆与二甲戊灵混配对棉田杂草防除效果

为明确敌草隆和二甲戊灵对棉田杂草的防除效果,采用不同剂量的敌草隆水分散粒剂、二甲戊灵乳油及其混剂进行土壤封闭,药后15 d、30 d、45 d调查棉田杂草数量,并在药后45 d测定杂草地上部干物质质量,计算株防效和鲜物质质量防效.结果表明,敌草隆和二甲戊灵混用对棉田禾本科和阔叶杂草均有较好的防除效果,其中敌草隆按照75...     

Soil Weed Seed Banks and Weed Management

Abstract

Studies of soil weed seed banks are of relatively recent origin considering their importance as sources of diversity and continued occupation of many types of habitats, including agroecosystems. The management of weed seed banks is based on knowledge and modification of the behavior of seeds within the soil seed bank matrix. The behavior of seeds defines the phenotypic composition of the floral community of a field. Selection and adaptation over time have led to the highly successful weed populations that exploit resources unused by crops. The weed species infesting agricultural seed banks are those populations that have found successful trait compromises within and between the five roles of seeds: dispersal and colonization, persistence, embryonic food supply, display of genetic diversity, and as a means of species multiplication. Diverse weed seed populations provide seed banks the opportunity to exploit any change in conditions to ensure their enduring survival and spread. The soil seed bank matrix is the spatial arrangement of environmental and physical factors over time. The behavior of soil seed banks at any level of biological, spatial, or temporal organization is a consequence of the accumulated, emergent behavior at lower levels of organization. Weed seed behavior arises from their sensitivity to environmental conditions within the physical structure of the soil seed bank. This sensitivity is reflected in changes of short duration (e.g., germination), during the annual life cycle, over multiple years (e.g., population shifts), and over evolutionary time. Understanding the processes that drive and control seed behavior will allow us to manipulate and manage weed seed banks in an economic and sustainable manner. This knowledge will allow us to implement improved, more informed, weed management systems and strategies. Important weed bank management strategies include prevention of seed introduction on farm, acquisition of weed biology information (including predictive tools), decision making about weed seed infestation levels and their implementation (eradication, reduction, tolerance), weed seed population shifts (within the seed bank, between species, increased diversity), and manipulations encouraging beneficial weed species. Environmental modification and changes in cropping systems can also be of considerable strategic importance in weed management.     

Weed Thresholds

Abstract

Weed thresholds are an integral component of an integrated weed management system (IWM). In this paper we review the literature on weed thresholds and examine the theory and applicability of thresholds within the context of a systems approach to IWM. The development of empirical models describing single and multi-species thresholds are reviewed and discussed in terms of the magnitude of weed threshold values in various crops and the importance and limitations of the parameters used to calculate these values. Mechanistic weed threshold crop competition models are suggested as a means of overcoming some of the limitations of empirically based threshold models. A mechanistic approach to the development of weed threshold models is desirable since relative crop and weed responses to environmental factors, cultural practices and the dynamic nature of competition are considered. Guidelines for the application of weed thresholds within a cropping system are outlined.     

Weed Biology,Cropping Systems,and Weed Management

SUMMARY

Weeds pose a recurrent threat to agricultural productivity in both industrialized and developing countries. Weeds respond dynamically to all cropping practices, and therefore, the design and function of cropping systems plays a central role in the composition of weed communities. The unique and challenging nature of weed communities requires more integrated approaches to weed management than are currently being employed by most growers. Integrating weed management with cropping system design and application may be an effective approach to diversifying weed management systems. Each crop-weed system is a unique mix of genetics and biology and will respond dynamically to changes in management practices. Practices such as crop rotation, tillage, cover crops, and fertility management modify weed populations. The challenge is to integrate these and other practices with the best available control tactics to generate integrated management systems. Cropping system design provides an excellent framework for developing and applying integrated approaches to weed management because it allows for new and creative ways of meeting the challenge of managing weeds. Weed science must integrate the theories and application of weed management into cropping system design based on the unique characteristics of weed communities and the available weed management options.     

糖料甘蔗生产杂草防除技术

主要从农业、化学、转基因等方面概述我国甘蔗杂草防除技术,并对甘蔗杂草防除技术研究中存在的问题及前景提出了展望。     

Weed control in rice seedling nurseries

Experiments were conducted in farmers' fields at Guimba, Nueva Ecija and at the International Rice Research Institute (IRRI), Los Baños, Laguna to test the efficacy of different methods of controlling weeds in rice (Oryza sativa L.) seedling nurseries. Hand weeding was laborious and ineffective due to the morphological similarities between rice and the Echinochloa species and the regeneration of perennial weeds. It was also injurious to rice seedlings. Manual separation of weed seedlings from rice seedlings before transplanting was ineffective, laborious, time consuming and expensive. Thiobencarb, butachlor, pretilachlor+fenclorim, propanil and quinclorac+bensulfuron were inexpensive and effective in controlling weeds in seedling nurseries without any deleterious effect on rice.     

Weed management in aerobic rice systems

Aerobic rice systems can substitute the conventional rice cultivation system in the wake of water shortage and energy crises. The major constraint in the success of aerobic rice is high weed infestation. Hence, we have discussed the weed flora, yield losses, herbicide-resistant weeds, need for integrated weed management, and approaches to manage weeds in aerobic rice systems. A review of several studies indicated that 90 weed species were competing with rice under aerobic systems, causing 23–100% reductions in grain yield. Weed control in aerobic rice gets difficult due to shifts in weed flora and herbicide resistance development in weeds. A wide increase in grain yield (15–307%) by implementing different weed control practices elaborates the scope of weed management in aerobic rice. Practices, such as soil solarization, sowing of competitive crop cultivars, stale seedbed preparation, mulch application, correct fertilization, and intercropping, were found to have particular significance for managing weeds in aerobic rice systems. Moreover, hand weeding and mechanical control were more effective when combined with other weed control methods. Herbicides, such as pendimethalin, 2,4-D, penoxsulam, ethoxysulfuron, bispyribac-sodium, triclopyr, imazosulfuron, bensulfuron, pretilachlor, and metsulfuron, were found most effective in aerobic rice systems. Keeping in view the severity of weed infestation in these systems and the evolution of herbicide resistance, reliance on a single control method is out of question. Hence, the approach of integrated weed management is the most appropriate for proper weed management and the subsequent success of rice cultivation using aerobic systems.