微量2,4-D丁酯对氟磺胺草醚增效作用的研究

在盆栽试验条件下，初步研究了2．4-D丁酯对大豆的安全剂量以及对氟磺胺草醚除草效果的影响。结果表明，在大豆2片复叶期施用2，4-D丁酯应在10．5ga．i．／hm^2以下；2，4-D丁酯与氟磺胺草醚混用能显著提高对苍耳的防效，2，4-D丁酯10．5ga．i．／hm^2与氟磺胺草醚312．5、375．5ga．i．／hm^2混用对苍耳的鲜重防效分别达到85．1％、92．7％；2，4-D丁酯10．5ga．i．／hm^2以下与氟磺胺草醚混用对大豆安全。     

大豆田后茬作物对金豆残留的药害反应

１９９６～１９９９年田间小区试验结果表明,大豆田使用不同剂量的金豆１２个月和２４个月后,小麦、玉米、油菜、甜菜、白菜等作物对土壤中残留的金豆有不同程度的反应。低剂量（４０,６０ｇａ．ｉ．／ｈｍ＾２）下,施药后１２个月对小麦、玉米、油极、甜菜和白菜等作物的出苗、生长和产量均无明显影响。８０、１２０ｇａ．ｉ．／ｈｍ＾２高剂量施药１２个月,小麦无明显药害症状,油菜和甜菜的株高、株鲜重和产量均不低于不施药     

唑嘧磺草胺土壤残留12个月对后茬作物的安全性

2001～2002年进行了80％唑嘧磺草胺WG土壤残留12个月对后茬作物影响的田间小区试验。结果表明,施用推荐量48ga．i．／hm^2和2倍量96g a．i．／hm^2,可以安全种植马铃薯、西瓜、高粱、西红柿和葱;施用3倍量144ga.i．／hm^2可以安全种植马铃薯和西瓜,高梁、西红柿和葱有一定的药害,不能种植。48ga．i．／hm^2对较敏感作物向日葵和亚麻有轻微药害,最好不种植,对敏感作物甜菜、甘蓝和油菜有较重药害,不能种植;96、144ga．i．／hm^2对向日葵、亚麻、甜菜、甘蓝和油菜药害严重,均不能种植。     

除草剂烯草酮的应用技术研究

在温室及田间条件下对烯草酮的作用特点、施药时期等进行了试验研究。温室试验结果表明,烯草酮的除草活性明显高于12．5％稀禾啶机油乳油,二者对稗草的ED90分别为36．2g／hm^2(有效成分,下同)和72.8g／hm^2;对大豆、棉花、花生、油菜等阔叶作物高度安全;烯草酮的最佳施药时期为禾本科杂草2～5叶期;烯草酮具有较好的耐雨水冲刷性,且明显好于稀禾啶;不同种类的禾本科杂草对烯草酮的敏感性不同,其中黑麦草对烯草酮最敏感,野燕麦较敏感,稗草中等敏感,狗尾草、马唐、牛筋草和看麦娘的敏感性略差。多点田间小区试验结果表明,烯草酮对大豆、油菜田发生的稗草、狗尾草、看麦娘、早熟禾等主要禾本科杂草均有较好的防除效果,处理后大豆、油菜无任何药害症状产生,应用剂量以72～108g／hm^2为宜,在此剂量范围内药后30～60d以上述杂草的鲜重防效可达85．1％～100％。     

莠去津对烟嘧磺隆药害及除草效果的影响

烟嘧磺隆在常规剂量下容易对敏感的玉米品种产生药害.盆栽试验表明:当烟嘧磺隆用量为90g a.I./hm2时,玉米糯203的株高和株重抑制率分别为32.4%和45.0%,并且心叶卷曲;当烟嘧磺隆以相同的剂量添加莠去津,两者单位面积用量的比为1∶12～12∶1时,玉米的药害程度随莠去津比例的提高而下降.当莠去津与烟嘧磺隆的用量比小于6∶1时,不能完全克服烟嘧磺隆的药害,而当它们的用量比提高到12∶1时药害症状完全消失.经两年田间试验证明:按照莠去津与烟嘧磺隆用量比为12∶1研制的19%烟·莠油悬剂,可以明显克服烟嘧磺隆对中度敏感玉米品种的药害,同时能够达到良好的除草效果.     

50%乙草胺微乳剂防除大豆田杂草及其安全性

50％乙草胺微乳剂于2002、2003年防除大豆田杂草结果表明,在剂量600g a．i．／hm^2以上时对一年生主要禾本科杂草及小粒阔叶杂草具有良好的防除效果,株防效在80％以上;55d鲜重总防效均达到85％以上。在试验剂量下对夏大豆产量无影响。     

甲咪唑烟酸模拟残留对后茬作物的敏感性

[目的]研究小麦、玉米、大豆、油菜、黄瓜等作物对花生田除草剂甲咪唑烟酸残留的敏感性。[方法]室内模拟添加生物测定法。[结果]甲咪唑烟酸对所有供试作物均存在不同程度的抑制作用,黄瓜、油菜、小麦、玉米、大豆根长的IC10值分别为0.013、0.68、13.14、85.87、399.14μg/kg,黄瓜、油菜、小麦、玉米株高的IC10值分别为7.32、37.61、133.28、345.56μg/kg。[结论]黄瓜、油菜对甲咪唑烟酸最为敏感,其次是小麦、玉米,大豆对甲咪唑烟酸残留的耐性最强。同一作物的不同部位对甲咪唑烟酸的残留敏感性也有较大的差异。甲咪唑烟酸施用108 g a.i./hm2的花生田,后茬作物不宜种植黄瓜、油菜和小麦。     

BAU-9403添加表面活性剂MON8161使用剂量研究

采用2个时期,3个BAU-9403使用剂量添加表面活性剂MON8161的二因素随机区组设计,分析研究了它们诱导小麦雄性不育的效果和对小麦生长发育的影响。结果表明：(1)所有处理均能诱导小麦产生100％的雄性不育率;(2)0．50kg／hm^2 MON8161处理的自然(人工)授粉结实率最高,分别为65．3％和37．6％,但与其它剂量间差异并不显著;(3)0．50kg／hm^2 MON8161处理对株高、穗下节长、穗长、小穗数、千粒重和发芽率等的影响明显小于0．75kg／hm^2 MON8161和1．00kg／hm^2 MON8161两个剂量。因此,0．50kg／hm^2 MON8161的使用剂量为佳。     

80%唑嘧磺草胺水分散粒剂苗前封闭处理对大豆苗期生长及其生理生化指标的影响

[目的]明确唑嘧磺草胺苗前封闭处理对大豆苗期生长及其生理生化指标的影响。[方法]通过盆栽试验的方法,设置0(清水)、30、60、120、240、480 g a.i./hm~2共6个剂量处理,药后28 d测定大豆幼苗的相关农艺性状及各生理生化指标。[结果]唑嘧磺草胺施用剂量为30~240 g a.i./hm~2时,大豆幼苗的株高、根长、茎叶鲜重、茎叶干重与对照相比均无显著差异,根鲜重显著低于对照;大豆叶片叶绿素含量随唑嘧磺草胺剂量的增加而降低,但在30 g a.i./hm~2和60 g a.i./hm~2用量下与对照无显著差异;大豆叶片SOD和CAT活性在30~120 g a.i./hm~2处理下与对照无显著差异,POD活性在30 g a.i./hm~2处理下显著升高23.29%;在30~120 g a.i./hm~2用量下MDA含量略低于对照,但当用量达到480 g a.i./hm~2时显著升高30.63%。[结论]唑嘧磺草胺在30~60 g a.i./hm~2范围内对大豆幼苗生长无抑制作用,对大豆无药害,表现出良好的安全性。     

呋草黄防除扁秆biao草生测试验探索

室内试验结果表明，呋草黄在600g a.i/hm^2剂量下，对扁秆biao草的鲜重防效为46.1% 1200g a.i/hm^2剂量下鲜重防效为82.2%，此剂量下水稻鲜重减少35.3%。田间小区试验表明，在1200g a.i./hm^2剂量下对扁秆biao草的株防效为65.0%，鲜重防效仅为40.8%，而此剂量下药后40天观察，水稻已有轻微药害表现，株高稍矮于对照。     

44%单嘧·扑灭WG防除夏谷子田杂草

采用田间小区试验方法进行了44%单嘧·扑灭WG防除夏谷子田杂草田间药效试验。结果表明:44%单嘧·扑灭WG在夏谷子田的用药量应为2100￣2400g/hm2,此剂量下施药后45d,药剂对杂草株数总防效为89.1%￣91.8%,对杂草的总体鲜重抑制率在85%左右。44%单嘧·扑灭WG在推荐剂量下施用对谷子安全,可以有效防除夏谷子田整个生长季中的杂草,封闭作用较好。     

15%乙·精微乳剂对大豆田杂草的试验效果

探讨了15%乙·精微乳剂(乙草胺 精喹禾灵)防除大豆田杂草的试验效果。结果表明,药后30d,该药剂在1500～2100mL/hm2(制剂含量)下对大豆田主要禾本科杂草具有很好的防除效果,株防效和鲜重防效分别达95%以上,对阔叶杂草也具有良好的防除效果,鲜重防效为80.1%～82.5%,对总体杂草的防效显著,株防效和鲜重防效分别为86.1%以上,与其它处理间有显著差异。各处理对大豆品种安全,大豆增产明显。     

Integrated fertilizer requirements of groundnut-wheat cropping system

Investigations were carried out in a long term field experiment from 1976 to 1982, on a loamy sand soil to find out the fertilizer requirements of groundnut and wheat grown in fixed rotation. Application of 26 kgP/ha to wheat alone was found to be sufficient for both wheat and succeeding groundnut. Application of phosphorus to both wheat and groundnut did not result in extra beneficial effect over P application to wheat alone. However, application of 26 kg P/ha to groundnut alone was not sufficient for succeeding wheat. There was no response from K application (25 kg K/ha) in either of these two crops. Increasing the dose of N from 50–150 kg/ha to wheat significantly increased the grain yield of wheat but the pod yield of succeeding groundnut were markedly lowered. Response of wheat to 150 kg N/ha was more marked when P was also applied to wheat and response was less when P was applied to preceding groundnut alone. Zinc application at 6.25 kg/ha to wheat alone resulted in significant increase in grain yield of wheat and pod yield of succeeding groundnut.     

Efficiency of nitrogen fertilizer use under rainfed maize and irrigated wheat at Kadawa,northern Nigeria

Field trials were conducted at Kadawa, northern Nigeria, during 1975–77 to study the efficiency of nitrogen fertilizer use under maize (Zea mays L.)—wheat (Triticum aestivum L.) rotation; the study also examined the impact of continuous N use on some soil properties. Grain and straw dry matter yields, grain N content, crop N uptake and whole plant N concentration of wheat at different growth stages increased significantly with increasing levels of N application. Per cent increases in mean grain yield of N treated plots over control were 77, 131 and 141 for maize and 195, 308 and 326 for wheat at 60, 120 and 180 kg N per ha levels, respectively. The calculated N rates for maximum yield were 177.5 and 164.0 kg N per ha for maize and wheat, respectively. Short-term beneficial effect of dung on maize yield was ascribed to its additional N supply. Urea and calcium ammonium nitrate (CAN) were equally good for both maize and wheat; full and split N application gave no significant difference in yield. The values for mean fertilizer N recovery over all the crops were 64, 58 and 44% respectively, at 60, 120 and 180 kg N per ha levels.Nitrogen application at the highest rate (180 kg per ha) reduced the soil pH significantly in the top 40 cm of the soil profile. The magnitude of soil acidification at levels of N below 120 kg per ha was not appreciable in this study. High N application also depleted the soil of its cations at differential rates. Other factors such as N source, time of N application and addition of dung along with N fertilizer did not have much influence on the rate of short-term soil acidification due to N fertilizer use.     

环庚草醚防除稻田杂草的试验研究

在秧苗移载后５天，每公顷用１０％环庚草醚乳油３００毫千，或１０％环庚草醚乳油１５０毫升＋１０％苄嘧黄隆呆湿性粉剂２２５克，用毒土不撤施，对水稻本田中的稗草、牛毛毡、异型莎草、鳢肠、丁香蓼等杂草的防效可稳定在９０％以上，且在此剂量下，对水稻及下麦子是安全的。     

25%砜嘧磺隆水分散粒剂在亚麻田中的除草效果及安全性评价

亚麻田中18.75g a.i.／hm^2砜嘧磺隆水分散粒剂的除草试验表明：药后50d,杂草鲜重防效达54％～99％,与对照相比达极显著差异。在本试验条件下,药后50d内,该药会稍稍抑制亚麻生长,表现出处理的苗矮于对照。但后期这个抑制会逐渐减轻或消除,亚麻生长正常,收割时植株高度与对照没有显著差异。因此,砜嘧磺隆对亚麻安伞,除草效果也好,可用于亚麻田除草。     

Phosphorus management of a rice-wheat cropping system

A long term field experiment was conducted on a sandy loam soil from 1983 to 1987 to determine how to best apply phosphorus fertilizer in a rice-wheat cropping system. The treatments included 9 combinations of phosphorus application either to both rice and wheat or to rice or wheat alone. Direct application of phosphorus at 13 kg/ha to both the crops resulted in significantly higher total productivity of the rice-wheat cropping system as compared with 26 kg P/ha applied either to rice or wheat alone. Phosphorus at 13 kg/ha for rice and 26 kg/ha for wheat was as efficient as 13 kg P/ha for rice and 13 kg P/ha for wheat. The higher rate of P (26 kg/ha) applied to both rice and wheat resulted a decline in the total productivity. The residual effects of phosphorus applied to either rice or wheat were significant to the succeeding crop but was inferior to its direct application. Phosphorus increased the leaf area index, chlorophyll content of leaves, and interception of more photosynthetically active radiation (PAR) which resulted in increased grain yield of rice and wheat. Phosphorus status of the surface soil declined markedly, in the absence of P application from 15.4 to 6.4 kg P/ha. Phosphorus applied at 26 kg P/ha to both the crops resulted a build up of the available P status of soil. Phosphorus application at 13 kg/ha to both rice and wheat maintained the phosphorus status of the soil at original level.     

Effects of three phenolic acids on chlorophyll content and growth of soybean and grain sorghum seedlings

Experiments were designed to test the hypothesis that interference with chlorophyll metabolism may be one mechanism of inhibition of plant growth in allelopathic interactions. Effects of ferulic,p-coumaric, and vanillic acids on soybean and grain sorghum growth and chlorophyll content were quantified and compared after seedlings were treated with these compounds in a nutrient culture. Following a 6-day treatment cycle, dry weights of soybean seedlings were reduced by both 10^–3 M and 5 × 10^–4 M treatments of ferulic,p-coumaric and vanillic acids. Soybean weight reductions in each case were paralleled by a significant reduction in the concentration (g Chl/mg dry wt) of chlorophylls a and b and total chlorophyll in the unifoliate leaves. Sorghum seedling growth was also reduced by each of the compounds at the 5 × 10^–4 M level, but leaf chlorophyll concentration was not below that of control plants.     

Comparative health effects of margarines fortified with plant sterols and stanols on a rat model for hemorrhagic stroke

There is increased acceptance of fortifying habitual foods with plant sterols and their saturated derivatives, stanols, at levels that are considered safe. These sterols and stanols are recognized as potentially effective dietary components for lowering plasma total and LDL cholesterol. Our previous studies have shown that daily consumption of plant sterols promotes strokes and shortens the life span of stroke-prone spontaneously hypertensive (SHRSP) rats. These studies question the safety of plant sterol additives. The present study was performed to determine whether a large intake of plant stanols would cause nutritional effects similar to those seen with plant sterols in SHRSP rats. Young SHRSP rats (aged 26–29 d) were fed semipurified diets containing commercial margarines fortified with either plant stanols (1.1 g/100 g diet) or plant sterols (1.4 g/100 g diet). A reference group of SHRSP rats was fed a soybean oil diet (0.02 g plant sterols/100 g diet and no plant stanols). Compared to soybean oil, both plant stanol and plant sterol margarines significantly (P<0.05) reduced the life span of SHRSP rats. At the initial stages of feeding, there was no difference in the survival rates between the two margarine groups, but after approximately 50 d of feeding, the plant stanol group had a slightly, but significantly (P<0.05), lower survival rate. Blood and tissue (plasma, red blood cells, liver, and kidney) concentrations of plant sterols in the plant sterol margarine group were three to four times higher than the corresponding tissue concentrations of plant stanols in the plant stanol group. The deformability of red blood cells and the platelet count of SHRSP rats fed, the plant sterol margarine were significantly (P<0.05) lower than those of the plant stanol margarine and soybean oil groups at the end of the study. These parameters did not differ between the soybean oil and plant stanol margarine groups. These results suggest that, at the levels tested in the present study, plant stanols provoke hemorrhagic stroke in SHRSP rats to a slightly greater extent than plant sterols. The results also suggest that the mechanism by which plant stanols shorten the life span of SHRSP rat might differ from that of plant sterols.     

Nitrophosphates and DAP are equally effective as P fertilizers for various crop species grown in rotation on a Typic Haplustept

In two long-term field experiments using wheat-maize and potato-sunflower-pearl millet (fodder) cropping systems on Typic Haplustept loamy sand, three different water-soluble P fertilizers [diammonium phosphate (DAP, water-soluble phosphorus content (WSPC) of 89.1%), ammonium nitrophosphate (ANP, WSPC 59%) and suphala (ammonium nitrophosphate, WSPC 26.7%)] were compared. Five amounts of P (0, 8.75, 17.5, 26 and 35 kg P/ha) were applied to wheat and (0, 13, 26, 39 and 52 kg P/ha) to potato. The succeeding crops under both the rotations used residual P from the P applied to wheat and potato crops. Grain yield and P content of wheat increased significantly up to an applied P level of 26 kg P/ha while the residual effect on maize crop was significant up to 17.5 kg P/ha. Tuber yield and P content of potato increased significantly up to an applied P level of 39 kg P/ha while the residual effect on sunflower and pearl millet (fodder) crops was significant up to 26 kg P/ha. Total profits in a year from wheat-maize and potato-sunflower-pearl millet (fodder) cropping systems increased significantly up to an applied P level of 26 and 39 kg P/ha, respectively. However, at all the levels of applied P and under both the cropping systems, the three P fertilizers used were found to be equally effective for plant yields, P contents, relative agronomic efficiencies and total profits in a year. Hence, it was concluded that the two nitrophosphates can be used instead of DAP as P fertilizers for the soil, plant species and crop rotations studied.