产量的影响

为明确15%炔草酯WP在油菜田的应用前景,建立油菜田的杂草管理体系,研究了不同开沟深度、不同时期施用15%炔草酯WP对油菜田杂草的控制作用以及炔草酯与其他药剂混用的效果,同时研究了该药剂对田间光照、养分、水分和油菜产量的影响。结果表明,开深沟有利于药效的发挥。在禾本科杂草处于1～2叶期时进行药剂处理,一般可以获得比较理想的除草效果。炔草酯与草除灵混用对禾本科杂草和双子叶杂草都具有良好的防除效果。施用15%炔草酯WP能显著提高油菜田间的透光率,降低杂草对田间养分和水分的吸收。15%炔草酯WP的施用对油菜株高、千粒重没有显著影响,但对油菜第一分枝高度、单株分枝数、角果数影响较大,能显著提高油菜产量。     

炔草酯的控草效果和对油菜田间光照、养分、水分及 产量的影响

为明确15%炔草酯WP在油菜田的应用前景,建立油菜田的杂草管理体系,研究了不同开沟深度、不同时期施用15%炔草酯WP对油菜田杂草的控制作用以及炔草酯与其他药剂混用的效果,同时研究了该药剂对田间光照、养分、水分和油菜产量的影响。结果表明,开深沟有利于药效的发挥。在禾本科杂草处于1～2叶期时进行药剂处理,一般可以获得比较理想的除草效果。炔草酯与草除灵混用对禾本科杂草和双子叶杂草都具有良好的防除效果。施用15%炔草酯WP能显著提高油菜田间的透光率,降低杂草对田间养分和水分的吸收。15%炔草酯WP的施用对油菜株高、千粒重没有显著影响,但对油菜第一分枝高度、单株分枝数、角果数影响较大,能显著提高油菜产量。     

20%氨氯吡啶酸·二氯吡啶酸·烯草酮可分散油悬浮剂防除油菜田杂草的效果

为明确新型吡啶类和环己烯酮类除草剂复配制剂对油菜田杂草的防控效果,指导新型除草剂在油菜田的合理使用,通过田间试验研究了20%氨氯吡啶酸·二氯吡啶酸·烯草酮可分散油悬浮剂对油菜田主要杂草的防除效果,以及杂草防除后对田间光照和杂草氮、磷、钾及水分累积的影响。试验结果表明,施用20%氨氯吡啶酸·二氯吡啶酸·烯草酮可分散油悬浮剂防除油菜田杂草效果显著,对菵草、大巢菜、看麦娘、牛繁缕等单双子叶杂草均有良好防效,总草鲜重防效可达88. 7%～98. 0%,显著优于两种对照药剂。杂草防除后,显著降低了杂草对田间氮、磷、钾和水分的消耗,有效地改善了田间光照和水肥条件。20%氨氯吡啶酸·二氯吡啶酸·烯草酮可分散油悬浮剂处理的油菜产量达到2 626. 26～2 836. 26kg/hm^2,增产效果显著,产量较空白对照增加18. 2%～27. 9%,增收2 173. 5～3 307. 5元/hm^2。研究结果表明,20%氨氯吡啶酸·二氯吡啶酸·烯草酮可分散油悬浮剂在油菜田有良好的应用前景,推荐剂量为每公顷使用有效成分225～300g。     

20%氨氯·二氯·烯草酮可分散油悬浮剂防除油菜田杂草的效果

     为明确新型吡啶类和环己烯酮类除草剂复配制剂对油菜田杂草的防控效果，指导新型除草剂在油菜田的合理使用，通过田间试验研究了20%氨氯吡啶酸?二氯吡啶酸?烯草酮可分散油悬浮剂对油菜田主要杂草的防除效果，以及杂草防除后对田间光照和杂草氮、磷、钾及水分累积的影响。试验结果表明，施用20%氨氯吡啶酸?二氯吡啶酸?烯草酮可分散油悬浮剂防除油菜田杂草效果显著，对菵草、大巢菜、看麦娘、牛繁缕等单双子叶杂草均有良好防效，总草鲜重防效可达88.7%～98.0%，显著优于两种对照药剂。杂草防除后，显著降低了杂草对田间氮、磷、钾和水分的消耗，有效地改善了田间光照和水肥条件。20%氨氯吡啶酸?二氯吡啶酸?烯草酮可分散油悬浮剂处理的油菜产量达到2 626.26～2 836.26 kg/hm2，增产效果显著，产量较空白对照增加18.2%～27.9%，增收2 173.5～3 307.5元/hm2。研究结果表明，20%氨氯吡啶酸?二氯吡啶酸?烯草酮可分散油悬浮剂在油菜田有良好的应用前景，推荐剂量为每公顷使用有效成分225～300g。     

磺酰脲类除草剂对抗性油菜田间杂草的防除效果及安全性评价

草害是影响油菜产量和品质的重要因素之一，种植抗除草剂品种，配合化学除草是解决油菜田杂草防治最经济有效的方法。为筛选适合抗除草剂油菜新品种搭配使用的除草剂，本研究以非转基因抗磺酰脲类除草剂油菜新种质M342为材料，比较了苯磺隆等11种磺酰脲类除草剂的防除效果和安全性。结果显示，11种磺酰脲类除草剂对油菜田杂草的鲜重防效均在70%以上，均能显著降低杂草对氮、磷、钾和水分的消耗。啶嘧磺隆对M342有严重药害，喷施后植株腐烂并逐渐坏死。苄嘧磺隆和氟唑磺隆也对M342的产量有显著影响，分别比人工除草对照减产6.22%和16.59%。其余8种磺酰脲类除草剂对M342的产量均无显著影响，可应用于抗磺酰脲类除草剂油菜新品种田间杂草的防除。     

野燕麦对油菜生长的影响及其经济阈值

采用添加系列试验和模型拟合的方法研究了不同野燕麦密度下油菜各生长性状的变化规律。结果表明,油菜在野燕麦的竞争干扰下,植株高度、分枝数、角果数及千粒重均随其密度的增加而显著降低,而第一分枝高度则不断增加。野燕麦能显著降低油菜植株间的透光率,其对田间25 cm高处的透光率影响较大,对75 cm和50 cm高处的透光率影响相对较小。野燕麦密度为5株&#8226;m-2时油菜产量显著降低,当其密度达到160株&#8226;m-2以上时,可使油菜减产达90%以上。对数模型y = 15.436lnx + 8.475可以较好地拟合野燕麦与油菜产量损失间的关系（P<0.0001）。油菜田野燕麦人工防除的经济阈值为1.15株&#8226;m-2,使用精噁唑禾草灵化学防除的经济阈值为0.70株&#8226;m-2。     

40%苄嘧·丙草胺可湿性粉剂防除水稻直播田一年生杂草田间药效试验报告

验证40%苄嘧·丙草胺可湿性粉剂对水稻直播田一年生杂草的防除效果及对水稻生长的安全性,探索其最佳使用剂量,结果表明:40%苄嘧·丙草胺可湿性粉剂用于防除水稻直播田一年生杂草具有较好的效果且对水稻安全、药效期长、用量低、能明显提高水稻产量等特点。使用该药剂防除水稻直播田一年生杂草应在播种后2~5 d,杂草出土前进行均匀喷雾,同时保持田板平整湿润,田沟内有水。从经济有效和安全性的角度考虑,最佳使用剂量100~120g/667m^2。     

阔世玛的麦田杂草防效及对小麦田间透光率和产量的影响

为给阔世玛可分散油剂的推广应用提供依据,通过大田喷施试验,研究了12 g·L-1阔世玛对小麦田间杂草的防效及对小麦田间透光率和产量的影响.结果表明,阔世玛时小麦田婆婆纳、野燕麦、大巢莱、猪殃殃、野油莱等杂草有较好的防除效果,可明显降低杂草株高、鲜重及养分和水分含量.抑制杂草生长,显著增加小麦田间的透光率和小麦产量.综合来看,阔世玛在麦田杂草处于2～6叶期时喷施,喷施剂量以8.1～13.5 g(a.i.)·hm-2为宜.     

华南地区大豆田杂草种子库特征与化学防除的研究

针对华南地区大豆田杂草防除问题,采用种子库诱萌法和田间药效试验法,研究田间杂草种子库的预测方法,筛选最佳化学防除方案.结果表明:杂草种子库共有杂草7科10属,主要分布在0～ 10 cm的土层,总出草量为6 861株·m-2.田间实际出草种类为6科9属,实际出草量平均为208株·m-2,占土壤杂草种子库总量的3.03％;6种除草剂都具有良好的防除效果,其中7.5％禾阔灵乳油的防除效果最佳,能有效防除禾本科杂草、莎草科杂草以及阔叶杂草,药后45 d鲜重防效仍达到70.7％～72.4％,可使大豆增产20.5％～ 34.5％.     

晚稻免耕抛秧化学除草剂筛选及使用方法探讨

通过对比试验,农泰等草甘膦类除草剂和克无踪等百草枯类除草剂对杀灭免耕稻田杂草和再生稻苗都有较好的防效,对未萌发的落粒谷苗防除效果不明显;晚稻免耕抛秧用41%农泰的适宜用量为6 000~7 500 g/hm2,伏草灵等大田除草剂在立苗后拌第1次追肥撒施效果较好。     

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.     

Effects of water-saving irrigation on weed infestation and diversity in paddy fields in East China

The purpose of the article is to investigate the effects of water-saving irrigation on weed infestation and diversity in paddy fields; a two-year field experiment was conducted in Gaoyou Irrigation District, China. The responses of two irrigation treatments, controlled irrigation (CI) and traditional irrigation (TI), were observed and compared. The irrigation water use, yield, weed density, coverage ratio, height, species richness, density, dominant species, Shannon–Wiener index, and Pielou index were examined to analyze the water productivity, weed infestation, and diversity in paddy fields under the two treatments. The results showed that the water conditions were similar before the late tillering stage, and thereafter the CI fields were alternatively dry and wet with shallow standing water and low soil water content, while the TI fields were mostly continuously flooded by deep standing water and high soil water content. Irrigation water use for CI was 46.8% lower than TI. The CI treatment reduced weed density by 38.0%, decreased coverage ratio by 13.8%, and resulted in a 39.0% increase in weed height. Fewer species were found in CI fields than TI fields. The Shannon–Wiener index decreased by 11.5%, and the Pielou index increased by 3.2%. The changed water regime under CI not only impeded the growth of dominant species but also placed the whole weed community at a relatively stable level with reduced weed density. Meanwhile, aquatic weeds were well controlled; however, semi-aquatic weeds became the dominant species. In general, CI effectively reduced the risk of weed outbreaks, and weed diversity also decreased when it reduced irrigation water use.     

丁草胺药肥对土壤微生物的抑制作用及其增产效果

众所周知,由于土壤氯化细菌加速尿素分解,尿素利用率仅为30%～35%。为此,科学家们试图寻找一些化学物质来抑制土壤微生物分泌的脲酶,以降低尿素的分解。国外曾报道,部分二苯醚类除草剂在常规使用剂量下能显著抑制土壤微生物的繁殖,部分脲类除草剂在使用早期时土壤微生物具有明显的抑制作用,有机磷类除草剂草甘磷使用后的2个月内明显减少真菌和细菌数量。但尚未见酰胺类除草剂对稻田土壤微生物的影响的报道。将除草剂和化肥合成固定剂型——药肥更是一种新的尝试。本试验的目的在于研究药肥对土壤微生物的抑制作用及其增产效果。1 材料和方法小区试验于1991年在浙江省宿阳县东山良种场进行,小区面积34m~2,重复3次,处理和对照见表1。完全随机区组排列。供试水稻品种为浙852,移栽后5d用丁草胺药肥处理,施用量112.5 kg/bm~2(商品量),人工撒施。丁草胺药肥由浙江省农资公司提供。施药后     

Tolerance of spring barley (Hordeum vulgare L.), oats (Avena sativa L.) and wheat (Triticum aestivum L.) to saflufenacil

Saflufenacil is a new herbicide being developed by BASF for pre-emergence application for broadleaved weed control in maize and other crops. Three field studies were conducted in Ontario, Canada over a 2-year period (2006 and 2007) to evaluate the tolerance of spring cereals (barley, oats, and wheat) to pre-emergence and post-emergence applications of saflufenacil at 50 and 100 g ai ha⁻¹. Saflufenacil pre-emergence caused minimal visible injury (1% or less) at 3, 7, 14 and 28 days after emergence and had no adverse effect on plant height or yield of barley, oats, and wheat. Saflufenacil plus the surfactant Merge (1% v/v) applied post-emergence caused as much as 76, 60, 52 and 35% visible injury in spring cereals at 3, 7, 14 and 28 DAT, respectively. Injury with saflufenacil plus Merge applied post-emergence decreased over time and was generally greater as dose increased. Saflufenacil plus Merge applied post-emergence reduced plant height by as much as 16% and reduced yield of spring barley and wheat by 24 and 13%, respectively, but had no effect on the yield of spring oats. Based on these results, saflufenacil applied pre-emergence at the proposed dose can be safely used in spring planted barley, oats and wheat; however, the post-emergence application of saflufenacil results in unacceptable injury and yield loss. These results are consistent with the proposed pre-emergence use pattern for saflufenacil.     

江汉平原油菜根肿病流行规律及栽培应对措施

 以枝江市问安镇龚桥村为例,采用普查和抽查方法,研究2008-2017十年间江汉平原油菜根肿病流行规律,分析土壤条件、栽培措施等因素对其爆发的影响。在前期研究基础上,采用随机区组设计方法开展无病苗分期播种移栽、苗床消毒、根际施肥用药等田间试验,优化防治技术。调查结果表明,江汉平原油菜根肿病扩散蔓延速度快,3～5年内连片发作,危害严重;机械作业是该病远距离传播扩散的主要原因,土壤酸化是其流行爆发的基础。田间试验结果表明,培育无病苗后移栽到病田避病效果明显,菜籽产量损失小,9 月中下旬育苗,10月中下旬移栽,重病田块能获得2 500 kg / hm2左右的正常产量;根际施用氰氨化钙和氰霜唑显著降低根肿病病情指数,防效分别为50%、90%,两者同时施用防效达100%;苗床氰氨化钙焖棚、火土灭菌、氟啶胺、氰霜唑淋土防治效果分别为100%、96%、76%、62%。基于江汉平原地区水稻土对根肿病极度敏感,在农业机械化生产的背景下,提出油菜根肿病防控应以预防为主。为了减少防治成本,提高防治效果,建议可将氰氨化钙等碱性钙肥丸粒化,作为种肥和底肥集中施用于根际周围;在此基础上无病和轻病田用氰霜唑种子包衣后直播,重病田块用氟啶胺进行苗床消毒,培育无病苗后移栽。     

A plant growth model for integrated weed management in direct-seeded rice. III. Interspecific competition for light

The model DSRICE1 was developed for analyzing integrated weed management strategies for direct-seeded rice. We have shown that DSRICE1 predicts monoculture rice growth well and accounts for water-depth effects on growth. Here, the model is used to simulate competition for light between rice and two weeds, Echinochloa oryzoides (early watergrass) and Ammannia spp. (redstem). Except for minor differences in phenology, weed growth was simulated as described for rice. Direct competition for light depended on the species' vertical distributions of leaf and stem areas (live and dead) and their extinction coefficients. Water also attenuates light, so species' early height growth rates were important because they determined when plants emerged into full light. Structural sensitivity analyses of rice in competition with the two weeds revealed that water-depth effects and leaf area distributions strongly affected competition, and shading by dead leaf and stem dry mass reduced total production. Validation was based on independent data sets for redstem and watergrass competition using several statistical tests and indices. For rice–redstem competition, DSRICE1 simulated rice growth well because redstem competitive effects were small, but predictions of redstem growth were good only when observed heights were matched in simulations. Redstem competitiveness depended on height growth rate, perhaps due to its small seed size. For rice–watergrass competition, the growth of both species was predicted well, except that watergrass growth in plots with early-season drainage was underpredicted. Watergrass parameters were similar to those for rice except for faster height growth and higher photosynthesis rates. In a model application, simulations in which rice seeding was delayed for a time after flooding led to greater yield losses from redstem than from watergrass because delays reduced the advantage of rice over redstem. The usefulness of DSRICE1 for drained fields will be improved by better simulation of plant growth responses to drainage, but rice competition with redstem and watergrass in continuously-flooded fields was simulated well.     

我国抗ALS类除草剂油菜种质创制与研究进展

化学除草是控制田间草害的有效手段,但我国油菜化除面积非常有限。创制对特定除草剂具有选择抗性的油菜新种质,选育抗性品种是实现我国油菜化除的有效途径。乙酰乳酸合酶(acetolactate synthase,ALS) 类除草剂具有高效低量、选择性强、杀草谱广等优点,在生产上得到广泛应用。本文简述了ALS 基因及其突变产生抗性的机制,着重介绍我国基于ALS靶酶突变的抗除草剂油菜种质创制、抗性生理生化和分子机理等方面的研究进展,并探讨了抗除草剂新种质在油菜抗性新品种选育、杂交油菜制种及抗性基因在转基因工程中的应用。     

黑龙江省水直播田杂草药剂系统防控技术

本文应用“二封一补”的策略完成黑龙江省水直播田杂草的药剂系统防控试验,结果表明,在16个有效处理中,处理5（25%噁草酮EC+25%丙炔噁草酮OD+10%吡嘧磺隆WP,50%丙草胺EC+33%嗪吡嘧磺隆WG,5%五氟磺草胺OD+30%氰氟草酯OD）防控效果最好,对总杂草的株数相对防效和鲜质量相对防效均为100%,产量也最高,达到7.77 t/hm²;处理6（25%噁草酮EC+25%丙炔噁草酮OD+10%吡嘧磺隆WP,50%丙草胺EC+33%嗪吡嘧磺隆WG,5%五氟磺草胺OD+48%灭草松AS）防控效果次之,对总杂草的株相对防效和鲜质量相对防效分别为99.92%和99.74%,产量也较高,达到7.65 t/hm²。此外,从首次出苗率、分蘖动态、株高动态、千粒重和结实率等指标来看,各处理间差别很小,无药害问题。