THE CONTROL OF WEEDS IN SPRING CEREALS WITH MCPA, MCPB AND 2,4-DB

Summary. Eighteen experiments were carried out over a period of 4 years jointly by the National Agricultural Advisory Service and the Agricultural Research Council Unit of Experimental Agronomy to compare the effects of spraying spring cereals with MCPA, MCPB, 2,4-DB and mixtures of MCPA and MCPB, at two different times. The first applications was made before the cereal crop had reached the five-leaf stage and when it was judged that most of the weeds had germinated. The second application was after the crop had reached the five-leaf stage, which is the time normally recommended in Britain for the application of MCPA to spring wheat or spring barley. The earlier applications produced better crop yields and gave a better control of weeds except where conditions for spraying were unsatisfactory or where a considerable number of weeds germinated subsequently. Mild deformity of the ears of the crop occurred in some experiments following early applications of MCPA, otherwise there were no marked differences in the effect on the crop of the different herbicides at the doses used; the dose of MCPA was less than that of the other herbicides. In view of these results and the lower cost of MCPA, it is concluded that MCPA applied early is the most efficient of the treatments tested except where the risk of malformed ears occurring is not acceptable.
Le désherbage dans les céréales de printemps avec le MCPA, le MCPB, et le 2,4-DB     

施肥对麦田杂草发生、生长及危害的影响

应用微区试验研究了在种植小麦的情况下,不同施肥水平对杂草及其防除效果的影响。结果表明,在缺磷土壤上单施氮肥,杂草发生和生长受到抑制;增施磷肥,氮肥效应得到充分发挥,杂草发生和生长迅猛提高。杂草根系发达,对钾肥不敏感。有机肥养分完全,显著促进杂草发生和生长。在不施肥(对照)及适合杂草和小麦生长的平衡施肥处理区(NP和NPK),麦田杂草的危害(小麦减产百分率)最为严重。杂草危害程度和施除草剂的增产效果均与小麦长势呈极显著负相关(相关系数分别是-0.5121、-0.5418,n=27)。肥料对甲磺隆钠盐杂草防效的影响与施药时间有关。在小麦苗前至苗后早期施药,防效高,且不受施肥影响;施药过迟,杂草长大,防效下降。研究结果还表明,杂草发生和生长在受施肥影响的同时,也受小麦长势和长相的影响。     

EFFECT OF TEMPERATURE ON THE ACTIVITY AND PERSISTENCE OF AMITROLE AND 2,4-D

Summary. One leaf of each of several tomato plants 5–6 weeks old maintained at 55, 70 or 85° F was dipped in 0.05 M amitrole or 0.005 M 2,4-D solution. The treated leaf was removed 1 week later. Scions taken from untreated plants were grafted to the treated plants at intervals up to 4 months after treatment.
Amitrole-treated plants maintained at 55° F were killed within 1 month but those at 70 and 85° F recovered.
Plants treated with 2,4-D showed typical symptoms when maintained at 70 and 85° F but no symptoms at 55° F. Scions grafted on plants maintained at 55, 70 and 85° F for 60 days after 2,4-D treatments exhibited typical symptoms. Grafts made more than 60 days following the 2,4-D application did not exhibit symptoms except a slight malformation on the plants held at 55° F.
New growth on the scions grafted up to 103 days after amitrole treatment on plants which had been maintained at 70 and 85° F exhibited typical amitrole symptoms (i.e. white foliage) but scions grafted after this lime did not. New shoots developing from buds on the treated plants also produced green growth 115 days after treatment but produced white foliage prior to that time.
Effet de la température sur l'activi'ité et la persistance de l'aminotriazole et du 2,4-D     

THE REACTION OF TRIFOLIUM REPENS (L.) IN GRASSLAND TO 2,4-D, MCPA AND MIXTURES OF 2,4-D AND MCPB

Summary. Eight experiments were carried out on a range of pasture lypes under different management and in different years to lest the reaction of white clover ( Trifolium repens in grasstand to doses of up to 4 lb/ac of the herbicides MCPA-sodium or-potassium and 2,4-D-amine. The initial effect of the treatments was to reduce the amount of dover in the sward, the size of the reduction varying greatly from field to field for any one dose. In general, the higher the dose, the more severe was the depression of the clover 1 month after spraying. Both herbicides at 2 and 4 lb/ac caused substantial depressions on some of the fields. The growth of the treated clover was examined during the year following spraying. The ability of the clover to recover from the initial depression varied considerably in the different fields; on some, recovery started in the year of spraying and on others in the following year. Quick recovery was usually associated with a high initial resistance but there were fields in which the clover showed contrasting rates of recovery following similar depressions. The experiments produced no clear-cut evidence as to why the initial resistance and speed of recovery varied in different fields. In one experiment the effects of MCPB-sodium and 2,4-D-amine on white clover were compared separately and in a series of mixtures. An examination made 6 weeks after spraying showed that MCPB at up to 8 lb/ac had no significant effect on the clover, whereas 2,4-D at 1 lb/ac caused a 22% reduction. Mixtures containing up to 0.37 lb 2,4-D and up to 6 lb MCPB caused no reduction while those containing 0.75 lb 2,4-D and 4 lb MCPB were not significantly different from 1 lb 2,4-D alone.
Reaction de Trifolium repens (L.) en prairie au 2,4-D, au MCPA, et aux mélanges de1, 2,4-D et de MCPB     

生长刺激剂及微量元素对于棉苗保健作用的效应

 过去,国內外許多学者証明,适当的应用微量元素和生长刺激剂处理种籽,对农作物苗期生长有促进作用,也常常收到提高产量的效果。关于应用于棉籽处理方面,波波甫应用了溴化鉀浸种,显著的提高了棉花的产量。     

THE EFFECT OF JULY APPLICATIONS OF DALAPON ON THE GROWTH AND BOTANICAL COMPOSITION OF AN AGROSTIS/LOLIUM PASTURE

Summary. Dalapon–sodium at 3.3–7.5 Ib ac/a.e. was applied in early, mid– and late July 1964 to an Agrostis/Lolium pasture for selective control of the weed grasses Agrostis stolonifera, Poa trivialis and Holcus lanatus. These species were significantly more susceptible than Lolium perenne to dalapon at all doses regardless of the time of spraying. The most promising treatment was 33 lb/ac applied on 4th July, which increased the ground cover of L. perenne and substantially reduced Agrostis stolonifera and Poa trivialis. The total yield of herbage 12 weeks after spraying was only 50% of that from the unsprayed control, but the yield of Lolium perenne was not affected. When cut on 21st May and 5th August 1965, total yield was only slightly reduced and that of L. perenne was increased by 60–90%. The successful practical utilization of this selectivity is likely to depend largely on the spacing of the plants of L. perenne in the pasture. Simazine at 0.75 Ib/ac applied to half of each plot 3–4 weeks alter dalapon treatment had no lasting beneficial effect on the composition of the sward.     

内蒙古锡林郭勒盟的草场承载力与畜草平衡分区

本文根据气候潜力推算出锡盟各旗县的草场承载力。并与实际载畜量的对比,将锡盟划分为4个亚区,进而探讨了各区发展畜牧业生产的途径。认为必须增加草场投入,逐步形成以集中养畜为主的现代生产方式,在高水平的畜草平衡关系上发展畜牧业。同时要限制开垦草场、开展区域协作、加强人口控制。     

THE CONTROL OF BROAD-LEAVED DOCK (RUMEX OBTUSIFOLIUS L.) IN NEWLY-SOWN RED CLOVER (TRIFOLIUM PRATENSE L.) WITH TRIFLURALIN, CARBETAMIDE AND ASULAM

Summary. Trifluralin (2,6-dinitro- NN -dipropyl-4-trifluoromethylaniline) pre-sowing, and carbetamide ( d - N -ethyl-2-(phenylcarbamoyloxy)propionamide) and asulam ( N -(4-aminobenzenesulphonyl)methylcarbamate) pre-sowing or post-emergence were evaluated for the control of Rumex obtusifolius L. in autumn-sown red clover ( Trifolium pratense L.). All herbicides gave good control of if. obtusifolius from seed. Asulam at 2 or 4 kg/ha gave the best control of R. obtusifolius from rootstocks, followed by trifluralin at 1 kg/ha and carbetamide at 2 kg/ha. Poa annua L. was controlled by trifluralin and carbetamide but not by asulam. The results are interpreted in terms of the mode of action and method of application of the herbicides.
La lutte contre la Patience sauvage (Rumex obtusifolius L.) dans un semis récent de trèfle rouge (Trifolium pratense L.) avec la trifluraline, le carbétamide et l'asulame     

蝗虫种群密度对牧草生长与损失量的影响

在贺兰山东麓天然草地,以黄胚小车ｅｄａｌｅｕｓ ｉｎｆｅｒｎａｌｉｓ Ｓａｕｓｓ为对象,进行了不同植物群落组成下不同蝗虫密度对牧草生长和损失影响的测定。田间笼养供试成虫,以实际取食日计取食时间,用目测法和收获法进行牧草生长量测定,用相关方差分析进行数据处理。结果表明;蝗虫取食对牧草生长的影响具有双重作用,在低密度时,有利于禾本科牧草的生长,随着种群密度的增多,对禾本科牧草的过量取食,会导致杂草增长     

不同施氮量对杂交水稻纹枯病、紫鞘病及云形病的影响

近年来,随着化肥生产的迅速发展,稻田施氮量逐年增加。有些地区由于有机肥料的减少,不适当的增施化肥,出现“偏氮、偏多、偏晚”的三偏现象,从而导致水稻病害严重发生。本试验从氮肥这单一因子出发,在其他栽培措施相同的条件下,通过定位观察,系统调查,以探明不同施氮量以及无机氮肥与有机氮肥一定的配比,对杂交水稻纹枯病(Rhizoctonia solain)、紫鞘病(Acrocylindrium oryzae)和云形病(Rhycho-sporium oryzae)发生的影响。     

不同时期使用农抗120控制花生网斑病侵染源的试验研究

用农抗120防治花生网斑病,不同使用方法效果不一。用常规喷洒叶面方法控制再侵染源,防效为21.4％,相当于多菌灵(29.4％);用农抗120和杀菌剂(抗枯灵或多菌灵等)混合,在花生播种时喷洒地面一次,控制初侵染源,防效为48.6％,用农抗120同杀菌剂混合,播种时喷洒地面,以控制初侵染源,7月上旬再喷洒叶面,控制再侵染源,效果最佳,防效高达70％以上。     

京津大白菜及其他十字花科作物霜霉病菌生理分化的初步研究

 应用十字花科蔬菜三属七种32个品种作为鉴定寄主,对京津地区12种十字花科蔬菜(大白菜、油青菜、芜菁、芥菜、大头青、雪里蕻、甘兰、苤兰、花椰菜、芥兰、萝卜和荠菜)上采集的34个霜霉病菌(Pronospora parasitica(Pers.) Fr.)标样进行了生理分化的研究。     

气候因素对禾谷缢管蚜发生程度的影响及预测

小麦禾谷缢管蚜Rhopalosiphum padi(L.)是本省小麦主要害虫,其发生程度受诸多因素的影响。作者通过整理1979—1987年田间系统调查资料,应用通径分析方法,对影响小麦禾谷缢管蚜发生程度的气候因子进行了研究。试验选取3月中旬均温     

温度和时间对水稻潜根线虫回收率的影响初步研究

 水稻潜根线虫(Hirschmanniella spp.)为水稻根内寄生,影响根系对水分相养分的吸收,使水稻地上部分表现缺素症状,导致水稻产量下降。在国内,水稻潜根线虫病尚属近年发现的一种水稻新病害,在南方诸省稻区广泛发生,作者从1984年开始从事此病的研究,发现以贝曼漏斗法分离水稻潜根线虫,其回收率与分离时的温度及分离时间关系甚为密切.     

青海高原农田野燕麦发生特点及除草剂应用技术的初步探讨

本文对青海高原农田野燕麦的发生特点,如出苗、生长发育、繁殖和传播、种籽抗逆性等进行了初步试验。为认识野燕麦的危害性和制定防除措施提供了依据。在化学除草方面,试验了十几种除草剂和不同的应用条件,初步认为“深埋药”、“狠抓水”、“防耗损”、“促生长”是保证药效的重要环节。对旱地除草剂的应用有一定参考意义。