棉花除草利用扇形喷头喷雾防堵塞方法

农药喷雾用的河沟渠水中含有垃圾杂质,经聚氨酯海绵漏斗可过滤掉水中所有不可溶性杂质而取得纯净水。装过滤漏斗在工农16型喷药桶上,16 L水过滤成纯净水仅需87秒钟。此装置过滤的纯净水兑除草剂对扇形喷头棉花行间除草可完全避免喷雾时喷头堵塞的现象。此法对离心式常规喷头亦有相同的防堵效果。     

农达防除棉田杂草效果简报

棉花生长期间，常受到杂草为害，人工除草不仅费功耗时且效果差。为了探讨棉田有效除草途径，我们于1997年进行了农达除草剂防除棉田杂草试验示范，效果十分显著。1基本情况1．1试验设计与安排试验设在定山镇东光村。棉田面积1334m2，田间以一年生杂草为主，供试棉花品种为泅棉3号。试验设2个处理，不设重复。处理Ⅰ：人工除草，面积66．7m2；处理Ⅱ：用41％农达水剂（美国孟山都公司产品）3000ml·hm-2，面积1267．3m2。1．2喷药时间及方法棉苗移栽成活后，于6月14日上午，用药3000ml．hm2兑清水450kg，选用工农16型喷雾器，喷头加保护罩，…     

壮苗除草灵在棉花上的使用效果

壮苗除草灵在棉花上的使用效果朱明华顾建辉黄颂禹黄淼娟沈小菊江苏省海门市农业局２２６１００壮苗除草灵是集棉花苗床除草和壮苗于一体的生化制剂,为了探索壮苗除草灵在棉花苗床上的除草与壮苗效果,于１９９７年在本市汤家乡闸北村陆忠平责任田安排了本试验。试验共...     

棉花化学除草免中耕增产技术

棉花化学除草免中耕增产技术贾永庆河北南宫市农业局０５１８３０１９８９～１９９３年进行了棉花化学除草免中耕增产技术的研究。在棉花播种前，棉田喷施除草剂，及时耙盖，棉花播种时用代森锰锌拌种，防治棉花苗期病害。适期播种保全苗，棉花生育期间不中耕除草，保持地...     

加强棉花中前期管理可减少蕾铃脱落

棉花花铃期是棉花生育期中最关键的时期，也是棉花蕾铃生长脱落的关键时期。如果6月份以前农家肥和当家肥施用不当，打药治虫不及时，使用农药不对路，或使用浓度过高，中耕除草破板结不力，田间除草药剂使用过多等，极易造成蕾铃脱落而影响产量。如何做到花龄期生长健壮，少脱落多结桃，笔者根据多年从事农技生产工作经验，现将主要措施整理如下，以飨同仁。     

41%农达棉田除草效果试验

试验设在广水市郝店镇沙子岗村 ,棉田草相为单子叶杂草占 70 %左右 ,双子叶杂草占 30 %左右 ,恶性杂草很少。棉花品种为湘杂棉 2号 F1,采用营养钵育苗移栽 ,宽窄行种植 ,宽行距 80 cm,窄行距50 cm,株距 55cm。试验设 4个处理 ,(A) 41 %农达(美国孟山都公司生产 ) 667m2 1 0 0 ml,(B) 41 %农达667m2 1 50 ml,(C)对照处理常规除草即人工除草 ,(D)喷清水 (CK) ,随机区组排列 ,3次重复 ,小区面积 1 0 .4m2 ,喷药器具采用手动喷雾器配合专用保护罩和定向喷头。试验选择在棉株茎部木质化 1 5cm以上、株高 35cm左右进行 ,施药时晴天微风 ,大多数…     

敌、乙草胺复配剂对棉花苗床期杂草的防除效果

通过对沿海所研究筛选的敌、乙草胺复配剂配方进行试验示范，结果表明，该药剂对棉花苗床单子叶杂草具90％以上的防效，对床内双子叶杂草亦有80％左右的除草效果。且对棉苗安全无副作用，完全可以在棉花生产上推广应用。     

20％草铵膦AS对棉田杂草的防效

20％草铵膦AS按照有效成分用量450～1800g·hm^-2进行棉花行间定向喷雾处理,其对棉田杂草的田间防效优于对照药剂41％草甘膦异丙胺盐AS1230g·hm^-2。该药剂不仅除草速度快,而且持效期长,能有效防除棉田多种常见杂草,且对棉花幼苗无不良影响。     

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。     

棉花生产轻简化的思考

棉花生产费工费时,已是制约棉花生产稳定发展的重要因素,因此,作者从简化棉花生产程序、提高棉花生产效益的角度出发,阐述了棉花生产的出路在轻简化,而轻简化的出路在于实施生产全过程的机械化。1棉花生产轻简化意义重大1.1传统的棉花生产过程需要轻简化棉花生产时间长。在长江中游棉区,棉花生产周期长达8个月。棉花生产用工多而繁琐、劳动强度大。现在棉花生产过程包含制作育苗营养钵、播种、苗床管理、大田除草整地、打穴移栽盖膜、补苗定苗、病虫防治、施肥除草、化学调控、整枝打顶、收花晒花、撕膜拔秆等大量程序,不仅费工多而且劳动强度大。成本高效益低。     

The impact of tillage system and herbicides on weed density,diversity and yield of cotton (Gossipium hirsutum L.) and maize (Zea mays L.) under the smallholder sector

The study was carried out to evaluate the impact of tillage system in combination with different herbicides on weed density, diversity, crop growth and yields on 18 farms in Kadoma, Zimbabwe. Experiments were set up as a split plot design with three replications on each farm. Tillage was the main plot (Conservation Tillage (CT), Conventional Tillage (CONV)) and weeding option (hand weeding, cyanazine, atrazine, glyphosate only and mixture of cyanazine + alachlor and atrazine + alachlor) as the sub-plots. Due to the heterogeneous nature of farmers' resource base, the farms were grouped into three farm types: high (Type 1), medium (Type 2) and poorly resourced farmers (Type 3). The hand hoe weeded treatments had 49 percent higher total weed densities in CT relative to CONV, and was statistically similar to the glyphosate treatment. The mixed pre-emergence herbicides reduced the diversity indices by 69 and 70 percent when compared to the hand hoe weeded treatment under CT in cotton and maize, respectively. The effectiveness of all pre-emergence herbicides were not influenced by tillage but were affected by farmers resource endowments with pronounced effect in Farm Type 1. Maximum plant heights of 85 and 238 cm were recorded for mixed pre-emergence herbicides under CT for cotton and maize, respectively. Minimum plant heights of 75 and 217 cm were recorded for the respective hand hoe weeded treatments. The hand hoe weeded treatments resulted in average cotton lint yield of 1497 and 2018 kg ha⁻¹ for maize. The mixed pre-emergence herbicides treatments gave yields of 2138 and 2356 kg ha⁻¹ of cotton and maize, respectively. The higher weed densities in CT under hand weeded treatments underscored the need for other weeding options. Similarly, a mixture of cyanazine + alachlor in cotton and atrazine + alachlor in maize is recommended for suppressing broad and grass weed populations and enhancing yields in CT systems.     

化学除草技术在杉木幼林抚育中的应用

研究了化学除草剂在杉木幼林抚育中的除草效果。结果表明,草甘膦和百草枯混合施用的除草效果好,优于单独施用,添加洗衣粉可以增强2种除草剂的除草效果。与传统的人工除草相比,杉木幼林采用化学除草可节约用工70%,节约资金53.8%。     

Weed control in conservation agriculture systems of Zimbabwe: Identifying economical best strategies

Weed management under conservation agriculture (CA), especially when manually controlled is one of the major setbacks for the widespread adoption of CA in southern Africa. This study was conducted at three on-station and three on-farm sites: CIMMYT-Harare, Domboshawa Training Centre and Henderson Research Station (on-station sites), Hereford farm, Madziva communal area and Shamva communal area (on-farm sites). The evaluation focused on the effect of initial herbicide application and succeeding manual weeding whenever weeds were 10 cm tall or 10 cm in length for grasses with stoloniferous–rhizomatous growth habit. Weeds counts, weeding time and grain yields were collected at all on-station sites. At the on-farm sites, weed counts were done before weeding and a number of farmers were timed during weeding. The results showed that herbicides use reduced the weed density and time taken on weeding at all sites. Combining herbicides e.g. atrazine, glyphosate and metalachlor had the lowest weed density and weeding time at all sites. However, the treatments had no effect on maize grain yields suggesting that appropriate and timely manual weeding reduced crop/weed competition. Herbicides treatments had higher input costs than manual weeding due to the additional cost of herbicide but the treatment with manual weeding only had more overall labour days compared to the mixture of three herbicides. In order to achieve economic benefits, smallholder farmers may use the time for value addition e.g. expand cropped land area, use time for value addition, or sell new products on the market. Herbicides use reduces the manual labour needed to control weeds and minimise total crop failure due to untimely weeding hence, herbicides are an important but not the only weed control option under CA systems in Zimbabwe.     

The ‘Electrodyn’ sprayer: first studies of spray coverage in cotton

A programme of investigation was started in mid-1977 in Spain into the performance of the ‘Electrodyn’ sprayer for the control of insect pests on cotton. The first stages of the programme, reported in this paper, evaluated the effect on spray deposition and distribution of emission height, speed of travel, wind speed, and position of the ‘Electrodyn’ sprayer nozzle relative to the row, in order to define the optimum method of use. In replicated field trials ultra-low-volume low volatile formulations were applied and performance was measured by assessing subjectively fluorescent spray deposition and distribution over samples of all plant structures at two heights in the plant. Plants were sampled from one row upwind and three rows downwind from each single spray run. The overall distribution of fully charged spray from the ‘Electrodyn’ sprayer was, in general, similar to that of discharged spray applied by the ‘Electrodyn’, with more than 80% deposited on ‘top’ leaves. A smaller proportion of the fully charged spray cloud penetrated to the lower half of the crop than did discharged spray. Variability from leaf to leaf was less and, of the total spray recovered, the proportion deposited on the main stem and branches in the top of the plant was four times greater, with charged than discharged spray. Cover of a greater part of the circumference of stems and branches and the only significant underleaf cover (the ‘wrap-around’ effect) was achieved by charged spray in the top of the plant and there was a concentration of spray at the tips and edges of leaves and bracts. Subjective assessments of deposition showed that 2·5 times more spray was recovered in the crop when charged than when discharged In practice the improvement could range from about 1·25 to 5 times depending upon the efficiency of the conventional system. Different speeds of travel, between 0·5 and 1·5 m/s (the highest reported) did not affect pest-control performance. An optimum mode of use was devised to facilitate subsequent comparisons of pest control between the ‘Electrodyn’ sprayer, rotary atomizers, and hydraulic nozzle sprayers. The ‘Electrodyn’ sprayer should be held downwind of the operator. At a nominal walking speed of 1·0 m/s in cotton less than 0·4 m tall, the nozzle is held 0·2 m directly above the row and all rows are sprayed: in taller cotton (0·4–1·5 m) the nozzle is held above the inter-row space and either taken along every inter-row with the nozzle 0·2–0·4 m above the crop, or, for low input/high risk crops (minimum levels of pest control) the nozzle is taken along alternate inter-rows, 0·4–0·5 m above the crop.     

Comparison of the growth and yielding of clove trees under different ring weeding and fertilizer regimens

Clove tree vegetative growth and yields were significantly improved by herbicide ring weeding compared with hand hoeing (‘jembe’ ring weeding). With jembe ring weeding, tree growth was not appreciably improved by using a larger ring weeding circle than normal. In non-intercropping situations, the application of nitrogen fertilizer or the use of herbicide ring weeding helped to prevent the appearance of the juvenile decline condition in young trees and increased tree yields. Nitrogen and phosphorus fertilizers stimulated weed growth and this was much better controlled by herbicide than by jembe ring weeding. The better weed control with herbicide ring weeding apparently made more of the applied fertilizer available and estimates of clove yields suggested that the maximum response of trees to nitrogen fertilizer occurred at a lower level with herbicide than with jembe ring weeding.     

汤原县水田除草方法演进

为科学地制定除草体系,在比较详尽地查实历史资料的基础上,将本县80a来的稻田除草方法划分为5个除草阶段,阐述了每个阶段的除草特点和除草效果,提出了今后稻田化学除草的发展方向。     

Effects of Weed-Free Periods on Organic Romaine Lettuce Production

Weed management in Romaine lettuce (Lactuca sativa L. var. longifolia) is an economic challenge for organic farmers. This study evaluated the effect of weed-free durations on crop yield and quality, weed densities and biomass, and weeding time in two growing seasons. Treatments included weedy entire-season; weed-free for 7 days after transplanting (DAT), 14 DAT, 21 DAT, 28 DAT, 35 DAT, 42 DAT; and weed-free entire season (49 DAT). Weeds were removed by hand-hoes and the time taken to weed each plot was recorded. Weed densities were recorded prior to each weeding and weed biomass was recorded at crop harvest. Total and marketable lettuce heads were recorded and crop quality was estimated. Weed interference up to 21 DAT resulted in approximately 45% total and 58% marketable yield loss. Weed control beyond this period did not result in significant (p < 0.05) increases in crop yield and quality. However, weed densities at the end of the season were 4- to 15-fold and weed biomass approximately 18-fold greater in plots kept weed-free only for 21 DAT compared with plots kept weed-free season-long. This suggested that weed seed-return may be a concern if late-season weeding is not conducted. To minimize weed seed-return, the plots would have to be kept weed-free for about 35 DAT. However, labor costs must be taken into consideration because the time required to hand-hoe was approximately 87 hr ha^?1 person^?1 greater in plots kept weed-free for 35 DAT compared with plots kept weed-free for 21 DAT.     

Development of Cotton Candy Method for High Productivity Polypropylene Fibers Webs

The cotton candy method (CoCAM) is developed for high productivity of polymer micro-and nano-fibers. Polypropylene was molten in a single screw extruder of the CoCAM at air pressures of 0.2-0.5 MPa with nozzle temperatures of 280-350 °C and the constant air temperature of 600 °C. The distance from the nozzle to the collector was set at 10-90 cm. Thermal images informed the accumulation of PP fibers flows at shorter collector distance. The diameters of PP micro-fibers decreased with increasing the air pressures and the nozzle temperatures. Crystallinity of the PP micro-fibers increased when increasing the nozzle temperature due to higher occasion of molecular orientation. The degree of the fiber entanglement in the PP micro-fibers decreased when increasing the collector distance, which affected on the declination of tensile strength. Ductility of the PP micro-fibers improved at high collector distances. The optimum condition of the PP micro-fibers was found at the average diameter of 2.3 μm at 0.5 MPa with the nozzle temperature of 340 oC collected at 60 cm. The productivity of the PP micro-fibers webs from the CoCAM was 144 g/h.     

Effects of saliva collection using cotton swabs on melatonin enzyme immunoassay

Background  

Although various acceptable and easy-to-use devices have been used for saliva collection, cotton swabs are among the most common ones. Previous studies reported that cotton swabs yield a lower level of melatonin detection. However, this statistical method is not adequate for detecting an agreement between cotton saliva collection and passive saliva collection, and a test for bias is needed. Furthermore, the effects of cotton swabs have not been examined at lower melatonin level, a level at which melatonin is used for assessment of circadian rhythms, namely dim light melatonin onset (DLMO). In the present study, we estimated the effect of cotton swabs on the results of salivary melatonin assay using the Bland-Altman plot at lower level.