STUDIES ON THE DEGRADATION OF 4-AMINO-3,5,6-TRICHLOROPlCOLINIC ACID IN SOIL

Summary. Picloram was incubated at concentrations of 0, 0·25, 0·5 and 1 ppmw in Regina heavy clay topsoil maintained at moisture-holding capacity and a t 25° C The herbicide was quantitatively bioassayed at regular intervals. There was a lag period prior to degradation at all concentrations. The duration of the lag period increased as the concentration of picloram in the soil was increased. Al the end of each lag period, the degradation of picloram occurred as a first-order reaction, i.e. the rate of degradation was independent of the concentration of picloram in the soil. Due to the pronounced variations in the duration of the lag periods with concentration, the assignment of half-value or half-life periods to picloram degradation in soil is considered to be of doubtful significance.
Etude de la degradation de t'acide 4-amino-3,5,6-trichloropicolmique dans le sol     

RATE OF DETOXIFICATION OF 4-AMINO-3,5,6-TRICHLOROPICOLINIC ACID IN SOIL

Summary. 4-Aniino-3,5,6-trichloropicolinic acid was incubated at 70° F in thirteen different soils for periods of up to 2 years at a concentration range of 0–023–24 ppm. Losses varied from complete to non-measurable by the bioassay technique employed. The percentage decomposed was generally greater for lower initial concentrations. The results were mathematically analysed in terms of zero-order, half-order, first-order and Michaclis-Menten kinetics. Half-order and Mirhaelis-Menten were found to be the kinetic expressions that most satisfactorily described the detoxification of the herbicide in soil.
Taux de deloxification de l'acide 4-amino-3,5,6-trichloropicolinique dans le sol     

EFFECTS OF TEMPERATURE AND SOIL TYPE ON THE PHYTOTOXICITY OF TRIFLURALIN

Summary. Wheat, oats, and green foxtail were grown at day-night temperatures of 32–16, 27–16, or 16–16°C in the growth chamber. The caryopses were planted at depths of 2·5 or 6·3 cm, and trifluralin was incorporated in the surface 5 cm of soil. The results indicated that the phytotoxicity of trifluralin was somewhat greater when plants were grown at day-night temperatures of 32–16°C than at a temperature regime of 16–16°C. A further study in the greenhouse indicated that the phytotoxicity of trifluralin was dependant upon soil properties. In general, the toxicity of trifluralin to both wheat and green foxtail appeared to decrease with an increase in the organic matter content of the soil.
Effets de la température et de la nature du sol sur la phytotoxicité de la trifluraline     

THE PHYTOTOXICITY OF SOME HERBICIDES IN FIELD AND POT EXPERIMENTS IN RELATION TO SOIL PROPERTIES

Summary. The phytotoxicities in a number of soils of lenacil, linuron, prometryne and simazine to two indicator plants were determined in field and glasshouse experiments. The results were compared with estimates of the adsorption capacity of the soils obtained by two methods using dimethylaminobenzaldehyde as a model adsorbate. The possible influence of other soil properties was also considered.
One of the adsorption measurements had some predictive value for glasshouse behaviour but was not markedly superior to soil organic carbon content for this purpose. None of the factors studied was usefully correlated with field performance. Results from field experiments in spring were poorly correlated with those from similar experiments in autumn. Neither set of field results related closely to those obtained in the glasshouse. It is concluded that the influence of climate was more important than that of soil type.
La phytotoxiciti de quelquts herbicides dans des experiences en pots et en plein champ, en relation avec les propriétés du sol     

灌淤土氧化还原特性的研究

本研究应用新的电化学方法，原位定期测定了灌淤土主要亚类－普通灌淤土、潮灌淤土和表锈灌淤土的土壤氧化还原状况．论述了土壤氧化还原状况的主要因素，提出了划分普通灌淤土、潮灌淤土和表锈灌淤土三个亚类土壤氧化还原电位及还原性物质总量的定量指标。     

黄土区侵蚀对土壤内在性质的影响

通过野外调查、定位监测及室内分析方法，研究了黄土区侵蚀对土壤内在性质的影响。结果表明：土壤中＜０．０１ｍｍ颗粒流失是造成耕地土壤“粗化”、结构恶化和养分降低的主要原因；耕地土壤结构的破坏程度随坡度、侵蚀强度增大而增大，养分流失总量随坡度增大呈幂函数增大，养分减少以氮素最快。     

残膜积累对土壤理化性状与后茬作物产量影响的研究

本文主要阐述通过小区与中间试验,研究了现推广的覆膜栽培技术。由于残膜积累,土壤理化性状低劣,使后茬作物产量下降。为减少地膜污染,建议采用膜外侧栽培。     

萘二甲酸酐减轻胺苯磺隆对水稻药害的作用机制

通过在离体和活体条件下萘二甲酸酐（NA）对水稻乙酰乳酸合成酶（ALS）活力的影响,进行NA减轻胺苯磺隆对水稻药害作用机制研究。离体条件下,NA对水稻幼苗ALS的活力影响很小,且未能产奋勇安苯磺隆对ALS活性的抑制作用。活体条件下,NA提高幼苗ALS活力达40％,且抵消胺苯磺隆对ALS活力的抑制作用,说明NA减轻胺苯磺隆对水稻药害的作用机制是NA间接激活靶标酶ALS。     

THE INFLUENCE OF THE METHOD OF APPLICATION OF PROMETON TO THE SOIL ON ITS TOXICITY TO WHITE MUSTARD (SINAPIS ALBA L.)

Summary. The effect of the method of incorporation of prometon into the soil on its phytotoxicity to white mustard was studied in pot experiments. Two groups of method were compared. In the first, the total quantity of soil to be used was mixed with the volume of appropriate prometon solution necessary to produce the required final herbicide and water concentrations. In the second group, the herbicide was initially mixed with a sub-sample of soil which was then diluted with untreated soil to give the required final concentration.
Phytotoxicity was greatest when procedures of the second type were followed. There was no difference between the behaviour of wettable powder and unformulated applications.
Influence de la méthode d'application de la prométone dans le sol sur sa toxicité pour la moutarde blanche (Sinapis alba L.)     

康氏木霉制剂对棉花和菜豆幼苗几个生理生化指标的影响

应用康氏木霉制剂后，分析测定棉花和菜豆幼苗的几个生理生化指标变化，结果表明：棉花幼苗的光合作用增强，呼吸作用不变，叶绿素含量增加；菜豆和棉花幼苗利用氮素能力增强，菜豆幼苗过氧化物酶及其同功酶活性降低，即菜豆幼苗的抗病性增强。     

高温低湿土壤对东亚飞蝗卵孵化的影响

本实驗証明:蝗卵的耐干、耐热性能,常因胚胎发育阶段而異。已吸水的越冬卵,在30℃恆温下可以在2.5％含水量的土壤内正常孵化;未吸水卵在同样温度下,則需要土壤含水量在8％以上才能正常孵化。吸水卵在土壤含水量适宜的情况下,可耐受短期的高温(60℃);而未吸水卵只能耐受55℃以下温度的处理。二者发育的最高温度界限都在41.5℃左右,超越此限,蝗卵孵化率的递減梯度,除随温度上升的幅度而加大外,并与高温的持續时間和土壤含水量的变化有关。     

家蝇免疫血淋巴的性质研究

带菌针刺诱导３６－４８ｈ后家蝇三龄幼虫免疫血淋巴的抑菌活性最高。其中抗菌成分为一种弱碱性物质,具有热稳定性耐低温的特性。毛细管区带电泳证实：针针刺诱导后家蝇免疫血淋巴的吸收峰与对照组大致相同,这表明家蝇抗菌物质的产生可能受结构基因调控。     

抗性大豆品种对大豆胞囊线虫侵入和发育的影响

 大豆胞囊线虫(Heterodera glycines)是一种严重为害大豆生产的植物寄生线虫,在我国主要产豆区东北和黄淮海地区均发生普遍。由于此线虫种内存在生理分化,不断培育种植抗病品种成为防治的重要途径。     

三种杀菌剂对水稻纹枯病作用特性的研究

试验结果表明,Monceren、Moncut、Mepronil对Pellieularia sasakii菌丝生长及菌核萌发均有强烈的抑制作用。其毒力顺序是,Monceren≈Moncut>Mepronil。菌核比菌丝对药剂敏感性弱,EC_(50)前者约为后者的25倍。经Monceren处理的Pellicularia sasakli菌丝形态生长异常,分枝增多且极度扭曲,在极度受抑的菌丛上形成少量的菌核。Monceren在50—2.5ppm均表现杀菌作用,Mepronil均表现抑菌作用,Moncut在50—5ppm具杀菌作用,2.5ppm具抑菌作用。 3种供试药剂抑制Pellicularia sasakii侵染作用的顺序是,Monceren≈Moncut>Mepronil;抑制病斑扩展作用的顺序是,Moncut>Monceren≈Mepronil。温室植株测定,Monceren、Moncut残效期达35天以上,Mepronil 24天。供试3种药剂对室内紫外光稳定性顺序是Moncut>Monceren>Mepronil     

温度和营养对北京地区蜡蚧轮枝菌生长发育的影响

在7～32℃温度中,北京地区蜡蚧轮枝菌菌落能生长并产生分生孢子。菌落生长的适宜温度为15～30℃,最适温度为23～28℃。产生分生孢子的适宜温度为20～28℃,最适温度为23～25℃,产孢量为6.32～6.94×10~9孢子/皿。分生孢子在4～35℃下均能萌发,适宜温度为15～32℃,一昼夜萌发率为81.36～96.60％。在23～28℃萌发芽管最长,20小时后达36.98～45.35微米。在10～15℃时,产孢量为7.42～8.25×10~3/皿,一昼夜孢子萌发率为42.99～89.20％,芽管长为9.10～16.94微米。该菌适应我国华北地区冬季温室温度偏低,昼夜温差较大的特点,为进一步研究应用该菌,更有效地控制温室白粉虱提供了依据。在6种琼脂培养基上试验,菌丝生长和产孢量均以麦芽汁培养基上为最好。     

温度、湿度、气压对截头堆砂白蚁原始繁殖蚁分飞的影响

经三年的室内试验观察，探讨了截头堆砂白蚁Cryptotermes domesticus(Haviland)原始繁殖蚁的分飞与温度、湿度、气压的关系。结果表明，该种白蚁分飞时适应的温度、湿度、气压范围较广，分飞时温度一般在25℃-30℃，相对湿度介于70％-90％，气压幅度在999百帕(hPa)-1006百帕(hPa)之间。温度在27℃-30℃之间较适宜，该种白蚁分飞次数较多，其中，28℃～29℃分飞次数最多，占总分飞次数的48.89％。相对湿度在70％-85％范围内分飞次数较多，其中相对湿度在75％-80％范围内分飞次数最多，占总分飞次数的35．35％。气压在1003百帕(hPa)～1005百帕(hPa)之间分飞次数较多，其中气压在1004百帕(hPa)-1005百帕(hPa)之间分飞次数最多，占总分飞次数的35．59％。