几种除草剂在早稻免耕田的药效试验

试验表明,41％农泰水剂,10％草甘膦水剂,74．7％水溶性农民乐颗粒剂和20％克无踪水剂4种除草剂对早稻免耕抛秧田杂草的防治效果较好,施药7～10d后杂草防治率在94．76％以上,可以大面积推广应用。     

几种抛秧田除草剂防除水稻免耕抛秧田田间杂草药效对比试验

对几种抛秧田除草剂进行防除水稻免耕抛秧田田间杂草药效对比试验,结果表明,53%苯噻酰.苄可湿性粉剂30g/666.7m2和35%苄.丙草可湿性粉剂60g/666.7m2能较好地防除水稻免耕抛秧田田间稗草、阔叶杂草和莎草,药后40d对杂草的株防效和鲜重防效均在80%以上。在推荐用量下,对水稻安全。     

16%抛秧保防除水稻抛秧田杂草效果及对水稻产量的影响

１６％抛秧保可湿性粉剂的有效成份为苄黄隆和乙草胺。但施用苄·乙除草剂防除水稻抛秧田杂草的试验，报道较少。为此，我们于１９９９年５～７月进行了１６％抛秧保防除早稻抛秧田杂草的效果试验，现将结果总结如下。 １材料与方法 １．１供试药剂 １６％抛秧保可湿性粉剂（浙     

抛秧田杂草发生与防除

抛秧田杂草发生种类多,数量大,危害重,已成为夺取水稻高产的一大障碍。为此,笔者于１９９５～１９９７年度就抛秧田杂草发生规律及化除技术做了一些研究,现将其结果初报如下：一、材料与方法１．出草规律调查选择杂草发生具代表性的抛秧田２块,以对角线五点取样法定...     

早稻免耕抛秧栽培病虫发生特点及原因简析

在不采取防治措施的情况下,抛秧田病虫总体发生重于插秧田。其中稻纹枯病发生从重到轻次序是常规抛秧→免耕抛秧→常规插秧;稻飞虱的发生从重到轻次序是常规抛秧→常规插秧→免耕抛秧;常规抛秧区的稻纵卷叶螟发生最重,常规插秧和免耕抛秧相当。并对这3种栽培方式病虫发生的特点及其原因进行了初步分析。     

10%苄嘧磺隆·异丙草胺可湿性粉剂对水稻抛秧田杂草的防除作用

由于水稻移栽方式的改变,华南地区抛秧稻田的杂草危害逐年加重,严重影响水稻的产量和品质。为此,采用大田药效试验的方法,研究10%苄嘧磺隆·异丙草胺可湿性粉剂对于华南地区抛秧早稻和晚稻田杂草的防除效果、最佳使用剂量及其安全性。结果表明:10%苄嘧磺隆·异丙草胺可湿性粉剂在水稻抛秧7 d左右进行药土法施药,推荐使用剂量101.25~112.50 g a.i./hm2,对水稻抛秧田稗草、鸭舌草、碎米莎草等常见杂草有较好的防效,具有显著的除草增产效果。     

抛秧田杂草发生特点初探

抛秧栽培作为水稻轻型栽培的方式之一 ,近年来在五桥推广面积逐年扩大 ,但随之出现的草害问题也越来越突出 ,并成为抛秧进一步推广的一大障碍。１９９８年 ,笔者开展了抛秧田杂草种群研究 ,１９９９年又对抛秧田杂草出草规律进行了调查 ,并总结出了抛秧田杂草的发生特点。现将其报告于后 ,以供大家在防除抛秧田杂草时借鉴或参考。１调查方法１．１调查器具计数器、标本夹、样方框（边长为１ｍ的正方形铁丝框）等。１．２杂草种群调查１９９８年７月５～１５日在新田、长岭、龙驹、白羊、走马、凉水、白土、罗田、太龙９个乡镇选择有代表性的…     

早稻抛秧田一次性化学除草效果试验

本文介绍了应用３５％丁苄可湿性粉剂、５０％杀稗王加１０％苄黄隆超微可湿性粉剂与泥土混合撒施对早稻抛秧田杂草的防除效果、安全性和增产作用。试验结果表明：在水稻抛栽后５ｄ施丁苄１２０ｇ、１５０ｇ以及在抛栽后７ｄ施杀稗王３０ｇ加苄黄隆１５ｇ对早稻抛秧田的主要杂草如稗草、莎草、鸭舌草、节节菜和矮慈姑等均有显著的防效，其总体防治效果可分别达到９６．１２％、９７．１３％和９８．７３％，且对水稻生长无不良影响，保产作用明显     

抛秧田化学除草与苯噻酰·苄

1996～1999年连续4年对南方抛秧稻田杂草发生规律及化学除草技术进行了研究。结果表明 :抛秧田杂草发生早、快、多 ,危害较移栽稻田严重 ,容易造成草荒。抛秧田除草要求除草剂的安全性更高、除稗效果更好。苯噻酰·苄WP用于抛秧田除草具有安全、高效、广谱、使用方便等特点 ,水稻增产明显 ,值得进行大面积示范和推广。     

苯噻草胺·苄防除抛秧田杂草的效果

长期以来抛秧田使用的除草剂品种单一 ,造成稗草产生抗药性。新型复配剂苯噻草胺·苄防除抛秧田杂草具有安全、高效的特点 ,并能延缓杂草抗性产生 ,且使用方便、成本低 ,应用前景广阔     

Incidence of benomyl and iprodione resistance in isolates of Botrytis cinerea in tomato crops in England and Wales in 1986

In 1986, mass-mycelial isolates of Botrytis cinerea from 67 tomato crops in England and Wales were examined for benomyl and iprodione resistance. Of the 706 isolates obtained, 62.7% were resistant to benomyl at 2μg/ml and 43.2% were resistant to iprodione at 2 μg/ml. Iprodione resistance persisted in the absence of a dicarboximide spray programme. The incidence of benomyl resistance has not decreased since the last survey in 1984 in spite of a considerable reduction in the use of benzimidazole fungicides. There were no clear indications that the use of dichlofluanid influenced the incidence of benomyl or iprodione resistance. Disease control was poorer in crops with a higher incidence of iprodione resistance.     

Plant-pathogen interactions of sunflower and Macrophomina phaseolina in vitro and in vivo

The relative pathogenicity of isolates of Macrophomina phaseolina was comparable both on sunflower tissue cultures and on mature plants and seedlings. The relative susceptibility of the different sunflower lines in vitro showed a similar pattern for cotyledon callus cultures, but not for immature embryo cultures. Although these protocols appear to be unsuitable for the selection of novel disease resistance, they do offer the potential for a rapid, non-destructive screen for resistant material.     

Changes in agronomic practices and incidence and severity of diseases in winter wheat in England and Wales between 1999 and 2019

In continuation of the annual national surveys of winter wheat, which began in 1970, samples from between 250 and 350 randomly selected wheat crops in England and Wales between 1999 to 2019 were visually assessed for disease symptoms during the milky ripe development stages (GS 73–75). Septoria tritici blotch was the most prevalent and severe foliar disease each year, although annual levels fluctuated considerably and there was no overall significant change over the two decades. Incidence of brown rust, yellow rust, take-all, and barley yellow dwarf virus also showed no significant overall change during the survey period, whereas glume blotch, powdery mildew, eyespot, and sharp eyespot all showed significant decline. Fusarium ear blight has significantly increased in both incidence and severity, causing a serious epidemic in 2012, when 96% of crops were affected. Tan spot has been the third most prevalent foliar disease since 2009 although severity is still very low. Regional disease levels were consistent over the two decades, providing reliable baselines to measure changes in seasonal disease severity. There were significant changes in agronomic practice with a rise to predominance of minimum tillage over the use of ploughing, decreases in overall disease susceptibility of cultivars grown, a major increase in the use of oilseed rape in the rotation and a long-term trend towards earlier sowing. Fungicide use increased considerably, with over 98% crops sprayed and an average of 3.5 applications made per crop each year since 2014. Implications of changes over the last 21 years are discussed.     

吡虫啉和百菌清在设施内外葫芦和黄瓜中的残留特性比较

采用高效液相色谱和气相色谱法,分别研究了吡虫啉和百菌清在薄膜大棚设施内外葫芦叶和黄瓜中消解动态及其在葫芦和黄瓜中的残留量,并结合气象因子对产生残留差异的原因进行了分析。样品中的吡虫啉经乙腈和盐酸溶液提取,中性氧化铝和弗罗里硅土层析柱净化后,用高效液相色谱检测;百菌清经乙腈提取,中性氧化铝层析柱净化后,用气相色谱检测。结果表明:吡虫啉在设施内外葫芦叶和黄瓜中均消解迅速,施药7 d后,其在设施内外葫芦叶上的消解率分别为90.4%和98.7%,在黄瓜中的消解率分别为67.8%和85.9%;而百菌清在葫芦叶上的消解速率均比在黄瓜中的稍慢,施药7 d后其在设施内外葫芦叶上的消解率分别为15.4%和38.1%,在黄瓜中的消解率分别为87.8%和91.5%。表明2种农药在设施外2种蔬菜上的消解速率均快于设施内的。两种农药均是在设施外葫芦及黄瓜中的残留量低于设施内的,而降雨和光照强度可能是引起农药在设施内外蔬菜上残留差异的主要因子。     

西部降水氢氧稳定同位素温度及地理效应

本文基于IAEA和WMO建立的GNIP网降水资料,得出中国西部地区大气降水线方程(LMWL)为δ2H=7.56δ18O+5.05‰(VSMOW)。分析了降水中氢氧稳定同位素温度效应、地理效应,确定了降水中δ18O和δ2H与月平均气温、降水量、海拔高度、纬度的相关关系。根据张掖站降水δ18O与温度之间的相关关系和民勤地下水14C年龄和δ18O特征,初步重建了晚更新世以来民勤盆地地下水补给温度,并与惰性气体补给温度(NGT)进行了比较,其相关系数为0.65,晚更新世地下水的补给温度(据δ-T关系)较大,可能是没有考虑降水量效应的缘故。     

Build-up and subsequent decline of residues of quintozene and hexachlorobenzene in lettuce in sequential crops

The build-up and decline of quintozene and hexachlorobenzene residues in protected lettuce, resulting from one to five treatments of the soil (each of 35 g m-2) with a quintozene formulation, have been studied. Residue levels were monitored in each experimental crop during growth until harvest. Residues in the soil at harvest were also determined. Quintozene residues in the harvested lettuce were in the range < 0.02–0.80 mg kg^?1 and those of hexachlorobenzene were in the range < 0.02–0.05 mg kg^?1 (expressed on a fresh weight basis). Residue levels in the soil were 5.4–231 mg kg^?1 for quintozene, and 0.20–5.4 mg kg^?1 for hexachlorobenzene (expressed on a dry weight basis). Under the experimental conditions of the trial there was no significant build-up of quintozene or hexachlorobenzene in harvested lettuce, even after five treatments to the same site.     

西安夏、秋季降水与太阳黑子的关系

基于西安市1960-2007年的降水数据和太阳黑子相对数,采用一元线性回归、Mann Kendall检验等方法,对西安降雨量进行分析,然后采用小波分析方法研究了西安夏、秋两季降水量与太阳黑子之间的关系。结果表明：夏、秋两季降水量约占西安全年降水量的80%;西安夏季降水量呈上升趋势,秋季降水量则呈下降趋势;降水量的变化与太阳黑子数多少密切相关,在太阳黑子出现极值年及2 a左右,降水量也出现极值;西安夏季降水量有10 a左右的周期,秋季降水量有9 a左右周期;太阳黑子在9 a时间尺度上与降水量有很强的相关性,且夏季降水量与太阳黑子相差1～2 a的正相关,秋季降水量则与太阳黑子提前2 a左右的负相关关系。     

Comparative ecophysiology of grain sorghum and Abutilon theophrasti in monoculture and in mixture

Selection of crop genotypes that are more competitive with weeds for light interception may improve crop yield stability in the presence of weeds. The effects of interference on ecophysiological characteristics of Abutilon theophrasti Medic. and three morphologically diverse grain sorghum hybrids was evaluated to determine the relative tolerance and suppressive ability of the three hybrids and specific traits that may contribute to those differences. A tall hybrid was more tolerant to A. theophrasti interference than two medium stature hybrids. Early leaf area growth of two medium-stature sorghum hybrids was reduced by A. theophrasti interference, whereas early growth of a tall hybrid was unaffected. The height of A. theophrasti was greater than two moderate-stature hybrids but lower than the tall hybrid. Greatest leaf area density (L_D) of the tall sorghum hybrid was above that of A. theophrasti , whereas greatest L_D of medium-stature hybrids was below that of the weed. In monoculture, the partitioning of new biomass to various plant organs was similar among sorghum hybrids, whereas the tall sorghum hybrid partitioned less biomass to leaves and more to stems than medium hybrids in mixture. The results indicate that the three hybrids differ in their susceptibility to A. theophrasti competition. Crop traits that may contribute to greater crop competitiveness include greater maximum height and its growth rate and greater height of maximum leaf area distribution.     

2009年融水县早、中稻稻瘟病大发生及流行因素分析

<正>稻瘟病(Pyricularia oryzae Cav)长期以来一直是为害融水县水稻生产的主要病害[1],为全县双季稻及早、中稻混栽区内常发性病害,历年发生面积333.3～533.3 hm2,尤其是一些历史老病区受此病为害,常造成水稻产量较大损失。2009年该病又相继在早、中