吡喃草酮在大豆上的残留动态

建立了高效液相色谱分析大豆中吡喃草酮残留的方法.吡喃草酮在土壤中最低检测限为0.005 mg/kg,在大豆植株和籽粒中最低检测限为0.01 mg/kg,半均回收率为74.2%～89.4%,相对标准偏差为0.6%～5.7%.吡喃草酮在土壤和大豆植株中的半衰期分别为2.8～3.1 d和2.4～2.9 d,在大豆植株中消解速度快于土壤,具有相似的降解规律,收获期土壤和大豆籽粒中检测浓度均低于最低检测限,属于低残留性除草剂.     

40%多菌灵SC在大豆和土壤中的残留动态

为了使多菌灵在大豆上的使用更加安全合理，将40％多菌灵SC于大豆播种前拌种进行田间试验，用高效液相色谱法，研究了多菌灵在大豆及土壤中的残留动态，测定了多菌灵在大豆及土壤中的残留量。两年的试验结果表明，多菌灵在大豆植株及土壤中消解较慢，其半衰期分别为18．3-21．6d和55．2-57．1d。大豆收获期籽粒和土壤中的最终残留量均低于0．005mg／kg和0．35mg／kg。     

乙氧呋草黄和苯嗪草酮在甜菜中的残留和降解

[目的]建立了甜菜、植株及土壤中乙氧呋草黄和苯嗪草酮的残留分析方法,并采用田间试验方法研究了乙氧呋草黄和苯嗪草酮在甜菜植株和土壤中的消解动态及其在甜菜、甜菜植株和土壤中的残留规律。[方法]样品用乙腈-水溶液振荡提取,经分散固相萃取净化,超高效液相色谱-串联质谱测定。[结果]乙氧呋草黄在甜菜、甜菜植株和土壤中的平均回收率为81.5%～99.1%,变异系数在4.8%～14.0%之间,最低检测质量分数为0.02 mg/kg;苯嗪草酮在甜菜、甜菜植株和土壤中的平均回收率为93.8%～104.9%,变异系数在1.1%～5.7%之间,最低检测质量分数为0.02 mg/kg。[结论]2016—2017年在黑龙江省田间残留试验表明:按照一级动力学反应模型拟合,乙氧呋草黄和苯嗪草酮在土壤中的半衰期分别为1.4～5.0、3.5～5.5 d,乙氧呋草黄和苯嗪草酮在植株中未拟合出半衰期;甜菜最终样品中乙氧呋草黄的残留量均0.02 mg/kg,苯嗪草酮的残留量均0.02 mg/kg。     

HPLC-MS/MS法测定甲霜灵在马铃薯和土壤中的残留量及消解动态

建立了马铃薯和土壤中甲霜灵残留的高效液相色谱-串联质谱分析方法,研究甲霜灵在马铃薯和土壤中的残留量及消解动态。试验结果表明,甲霜灵在马铃薯植株和土壤中消解较快,半衰期分别为1.5～3.4 d和9.0～13.4 d。马铃薯中甲霜灵最终残留量为0.005～0.013 6 mg/kg,低于我国残留限量标准;土壤中甲霜灵最终残留量为0.020 8～0.395 0 mg/kg。该方法快速简便、准确可靠。     

丙炔(噁)草酮在马铃薯和土壤中的残留及安全使用评价

[方法]采用田间试验方法,对丙炔(噁)草酮在马铃薯植株及土壤中的残留消解动态及最终残留量进行了研究,用气相色谱电子捕获检测器进行定量分析.[结果]消解动态试验结果表明:丙炔(噁)草酮在土壤中的半衰期为12.9～13.6 d,在马铃薯植株中原始沉积量较低,无法计算半衰期;最终残留量试验结果表明:80％丙炔(噁)草酮可湿性粉剂按施药剂量为216、324 g a.i./hm2,喷药1次,收获期马铃薯块茎中丙炔(噁)草酮的残留量均未检出,土壤中丙炔(噁)草酮残留量为0.0393～0.0695 mg/kg.[结论]推荐80％丙炔(噁)草酮可湿性粉剂在马铃薯上使用安全间隔期为收获期.     

25%西草净WP在水稻、田水和土壤中的残留动态分析

[目的]建立测定水稻、田水和土壤中西草净上的残留量气相色谱质谱联用分析方法。[方法]通过田间试验和气相色谱质谱联用分析技术研究25%西草净可湿性粉剂在水稻、田水和土壤中的消解动态及其最终残留量。[结果]吉林长春市、黑龙江海伦市和湖南长沙市2年3地的田间试验结果表明:2011年,西草净在水稻植株、田水和土壤中的原始沉积量分别为5.048 mg/kg、22.299 mg/L和7.730 mg/kg,半衰期(t1/2)分别为2.5、1.4、3.9 d;2012年,西草净在水稻植株、田水和土壤中的原始沉积量分别为5.854 mg/kg、5.854 mg/L和0.090 mg/kg,半衰期(t1/2)分别为1.6、1.7、2.9 d。最终残留试验表明西草净在糙米、稻壳、稻株和土壤中的最终残留量均小于0.02 mg/kg。[结论]25%西草净可湿性粉剂可以在水稻上使用,但施药剂量最高为3 750 g/hm2,施药1次。     

联苯菊酯在小麦和土壤中的残留消解动态

为评价联苯菊酯在小麦上使用的安全性,开展联苯菊酯在小麦和土壤中的残留试验研究。田间试验结果表明,联苯菊酯在小麦植株和土壤中的消解行为均符合一级降解动力学方程,其消解半衰期分别为6.4～15.3 d、12.3～18.0 d。收获期小麦植株、小麦籽粒和土壤中联苯菊酯残留量分别为0.042～1.226 mg/kg、小于0.010～0.022 mg/kg、小于0.010～0.053 mg/kg。     

灭草松在大豆和土壤中的残留消解规律

[目的]研究灭草松在大豆及土壤中的残留消解趋势,评价其在大豆上使用的安全性。[方法]采用液相色谱(HPLC)对31%灭草松·三氟羧草醚·氟磺胺草醚微乳剂在3地大豆和土壤中的残留消解动态和最终残留进行了研究。[结果]灭草松在大豆植株中的半衰期为0.7~7.2 d,在土壤中的半衰期为1.8~8.6 d。大豆苗后施药,在收获期采收的鲜食青豆和成熟大豆中残留量都低于最低检出限0.02 mg/kg。[结论]灭草松按照推荐方法和剂量使用,在大豆上使用是安全的。     

10%博邦水分散粒剂在京皖两地梨和土壤中的残留动态研究

采用田间试验的方法,研究了10%博邦水分散粒剂在梨及土壤中的消解动态和最终残留量.试验结果表明,博邦在梨中消解较快,半衰期为7.24d～9.07d,在土壤中消解相对缓慢,其半衰期为13.38d～19.15d.10%博邦水分散粒剂按最高推荐浓度200mg/kg和最高推荐浓度的2倍400mg/kg施药3次、4次,采收距最后一次施药间隔14d,博邦在梨中残留量为0.0414mg/kg～0.0982mg/kg,土壤中残留量为0.0057mg/kg～0.1799mg/kg.该药属于低毒农药,按推荐剂量使用是安全的.     

丙酯草醚在土壤中的残留及对后茬作物的安全性

研究了新型除草剂丙酯草醚(ZJ0273)在河北石家庄和湖北武汉油菜田土壤中的降解规律,以及后茬作物对丙酯草醚敏感性的室内模拟试验。结果表明:丙酯草醚在土壤中残效期较短,在河北石家庄和湖北武汉油菜田土壤中的降解半衰期分别为12.2、0.9d,且残留量较低,油菜收获时土壤中最终残留量均低于0.01mg/kg;不同作物对丙酯草醚敏感性不同,其中以茄子、南瓜、辣椒、玉米、棉花等作物对丙酯草醚较敏感,其株高的ED10值分别为0.0262、0.0353、0.0415、0.0422、0.0456mg/kg,而水稻、花生、大豆和豇豆等作物对丙酯草醚具有一定耐药性,其株高的ED10值分别为0.1471、0.6617、9.09、21.091mg/kg。可见油菜收获后土壤中的丙酯草醚残留量对后茬作物无明显影响。     

Characterization and possible agricultural application of polyacrylamide/sodium alginate crosslinked hydrogels prepared by ionizing radiation

Polyacrylamide/sodium alginate (PAAm/Na‐alginate) crosslinked copolymers were prepared by using electron beam irradiation. The gel content and the swelling behavior of the obtained copolymers were investigated. The thermal and morphological properties of the prepared copolymers were studied using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The thermal stability of PAAm significantly changed when mixed with Na‐alginate. The addition of PAAm/Na‐alginate copolymer in small quantities to sandy soil increased its ability to retain water. The growth and other responses of the faba bean plant cultivated in a soil treated with PAAm and PAAm/Na‐alginate copolymer were investigated. The growth of the bean plant cultivated in a soil containing PAAm/Na‐alginate was better than that cultivated in soil treated with PAAm. The most significant difference between the PAAm and its alginate copolymer is that the latter partially undergoes radiolytic and enzymatic degradation to produce oligo‐alginate, which acts as a plant growth promoter. The increase in faba bean plant performance by using PAAm/Na‐alginate copolymer suggested its possible use in the agriculture field as a soil conditioner, providing the plant with water as well as oligo‐alginate growth promoter. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3572–3580, 2006     

Aboveground nitrogen in relation to estimated total plant uptake in maize and bean

The main objective of this field study was to estimate the total plant uptake of soil mineral N in maize (Zea mays L.) and common bean (Phaseolus vulgaris L.) grown in crop rotations under different N content in Nicaragua. Secondary objectives were to estimate the fraction of the measured soil mineral N content taken up in this way, and to determine how the measured N in plant aboveground parts was related to the total mineral N uptake. A large variation in N content was obtained by using data from fertilisation experiments. Plant total N uptake was estimated as the residual N in a mass balance calculation of soil mineral N. Mineral N content in the top 0–0.3 m soil layer in the field cultivations and in tubes isolated from root uptake, and N content in aboveground plant parts were measured every 30 days. Estimated plant total uptake of soil mineral N varied considerably (2.5–14 g N m⁻² 30 day⁻¹) over periods and N treatments. The range of variation was similar for maize and bean. The fraction of the soil mineral N that was taken up by the plant daily varied more in maize (about 0.03–0.12 day⁻¹) than in bean (about 0.05–0.08 day⁻¹). Our results suggest that monthly changes in N in aboveground plant parts were linearly related to plant total N uptake during the same period. Aboveground plant N constituted between about 55% and 80% of total uptake of soil mineral N in maize depending on period within season, whereas for bean it was more constant and smaller (about 40%).     

Nutrient dynamics in a climbing bean and sorghum crop rotation in the Central Africa Highlands

Bean (Phaseolus vulgaris L.) is a major crop in Eastern and Southern Africa, but yields are low. Climbing bean is much more productive than bush bean and is gaining importance with small scale farmers. Our objectives were to: compare nutrient balances with climbing and bush bean in a grain sorghum (Sorghum bicolor L.) based crop rotation system; and to determine the effect of management alternatives on the productivity of the subsequent crop. Different yearly crop rotations alternating sorghum with another crop were compared over six seasons in the highland area of southwestern Uganda at a steeply sloping, terrace site with clayey, acidic soil. The rotation treatments were climbers, bush bean, non-nodulating bush bean, and wheat (Triticum aestivum L.) with the whole plant harvested, and climbers with only pods harvested. Yield of climbing bean exceeded bush bean yield by 120% over three seasons. Sorghum yielded most grain in the rotation with climbing bean where only pods were harvested, while yield did not differ for the other treatments. Nutrient balances were more negative for the climbing bean rotations than for bush bean rotation. Nitrogen derived from the atmosphere was estimated to be 40% of plant N for both climbing and bush bean using the difference method, but 57% using the¹⁵N abundance method. Of the total N removed in crop harvest over the six season period, a greater proportion was estimated to be derived from the atmosphere for the climbing bean rotations than for bush beans. This revised version was published online in August 2006 with corrections to the Cover Date.     

手性除草剂喹禾糠酯的合成工艺改进

以6-氯-2-(4-羟基苯氧基)喹喔啉与(S)-2-对甲苯磺酰基丙酸乙酯为主原料,经酯交换、取代反应合成喹禾糠酯,总收率91.2%,总酯含量95%,光学纯度95%。方法操作简单、收率高,适合于工业化生产。     

Improvement of leguminous vegetables production in calcareous soil by addition of some acidifying materials

Two field experiments were carried out in two sites of Noubaria Agricultural Research Station Farm. The investigated acidifying materials were sulphur, superphosphate and Phosphorine. The materials were mixed with cowpea seeds just before sowing in a rate 1 kg for seeds required to 1 fed (4200 m²) in the first experiment. Additions were 100, 30 and 1 kg S, P₂O₅ and Phosphorine/fed, respectively to soils before common bean planting in the second experiment where the two varieties Giza 3 and Giza 6 were put under investigation. The residual effect of the soil additions was investigated using bean as a test crop.The obtained results showed that acidification materials were effective in such soil for seed yields of cowpea and common bean - while the residual effect on bean was unconsiderable. The variety Giza 6 of common bean was significantly superior to Giza 3. The harvesting index was higher by using sulphur or superphosphate than Phosphorine in the case of cowpea while in common bean superphosphate and Phosphorine were more active in increasing this index than sulphur. Acidification process resulted in some increases in harvest index of bean regardless the used material. As for 100 seed weight, it was raised in significant level by using sulphur or superphosphate than Phosphorine or control in the case of cowpea while all treatments were statistically equal in the case of common bean and bean.     

腐植酸缓释磷肥的试验研究

采用绿豆盆栽,初步研究了石灰性土壤中腐植酸对磷酸氢钙的活化作用,磷酸氢钙中的磷素呈枸溶性,但在与腐植酸作用后,随着土壤中的物理、化学与生物变化,磷素缓慢释放,满足了绿豆在生长期间所需要的磷素,能促进绿豆生物量的积累。所有的施磷处理较对照绿豆产量呈极显著增加。说明腐植酸能减少土壤中磷的固定,提高磷酸氢钙中磷的有效性。     

Soil application of ash produced by low-temperature fluidized bed gasification: effects on soil nutrient dynamics and crop response

Recycling of residual products of bioenergy conversion processes is important for adding value to the technologies and as a potential beneficial soil fertility amendment. In this study, two different ash materials originating from low temperature circulating fluidized bed (LT-CFB) gasification of either wheat straw (SA) or residue fibers mainly from citrus peels (CP) were tested regarding their potential to be used as fertilizer on agricultural soils. A soil incubation study, a greenhouse experiment with barley and faba bean, and an accompanying outdoor experiment with maize were carried out to investigate the effects of the ashes on soil microbiological and chemical properties and on the response of the three crops. The ash treatments were compared with a control treatment that received only nitrogen, magnesium, and sulphur (CO) and a fully fertilized control (COPK). Soil microbial parameters were not significantly altered after ash application. SA was generally able to increase the levels of Olsen-P and of the ammonium acetate/acetic acid-extractable K in soil as well as to improve the yield of barley and maize, whereas faba bean did not react positively to ash amendment. CP did not show beneficial effects on soil nutrient levels or on crop biomass. We conclude from the results of this study, that??depending on the feedstock used??ashes from LT-CFB gasification of plant biomass can be used to replace mineral fertilizers if they are applied according to their nutrient content, the crop demand, and soil properties.     

Profitability of agro-forestry based soil fertility management technologies: the case of small holder food production in Western Kenya

Persistent food insecurity accompanied by low and declining farm household incomes are a common feature of many small holder maize and bean producers in western Kenya. This has been largely attributed to soil nutrient depletion, among other factors. One way of addressing soil fertility problems in many maize-based cropping systems is the use of agro-forestry based technologies. We carried out a survey in western Kenya (Vihiga and Siaya districts) aimed at analyzing the financial and social profitability of use of agroforestry based (improved tree fallows) and other soil fertility management technologies among smallholder farmers. The Policy Analysis Matrix (PAM) was used to determine the financial and social profitability of different production systems, which were categorized on the basis of the technology used to address soil fertility. Farm budgets were first prepared and in turn used to construct the PAMs for six production systems namely: maize–bean intercrop without any soil fertility management inputs; maize–bean intercrop with chemical fertilizers only; maize–bean intercrop with a combination of chemical fertilizers and improved fallows; maize–bean intercrop with improved fallows only; maize–bean intercrop with a combination of improved fallows and rock phosphate; and maize–bean intercrop with Farm Yard Manure (FYM) only. Results revealed that use of chemical fertilizers with improved fallows was the most profitable technology and thus the study recommended that farmers be encouraged to intensify the use of chemical fertilizers. To make chemical fertilizers more accessible to farmers, the study also recommended that good linkages be made between farmers and micro credit institutions so that small scale farmers are not actually biased against due to lack of collateral when credit is being advanced to clients.     

Evidence that ribonuclease activity present in beetle regurgitant is found to stimulate virus resistance in plants

Phaseolus vulgaris L. cv. 'Pinto' bean is a local lesion host for the plant pathogen Southern bean mosaic virus (SBMV) and its vector is the Mexican bean beetle, Epilachna varivestis Mulsant. The objective of this study was to determine if prior feeding by the beetle would affect 'Pinto' bean's resistance to SBMV and determine if ribonuclease (RNase), a major constituent of beetle regurgitant, mediated the plant's response to the virus. 'Pinto' bean plants fed upon by beetles had increased resistance to plant viruses compared to non-wounded or mechanically wounded and buffer-treated plants. Plants that were mechanically wounded and treated with RNase had increased resistance to plant viruses that was equal to plants fed upon by adult beetles. The induction of plant pathogen defenses could be a good adaptation for the plant in the presence of a beetle and pathogen threat. This evidence suggests that RNase activity in the beetle regurgitant could function as an insect-derived elicitor of plant resistance to viruses.     

Fatal Attraction: <Emphasis Type="Italic">Ricinus communis</Emphasis> Provides an Attractive but Risky Mating Site for <Emphasis Type="Italic">Holotrichia parallela</Emphasis> Beetles

The castor bean, Ricinus communis L., is a non-host plant for the large black chafer, Holotrichia parallela Motschulsky (Coleoptera: Scarabaeidae). In laboratory bioassays we found that this plant was no less attractive than the main host plant (peanut, Arachis hypogaea) and three food plant species: velvetleaf (Abutilon theophrasti), the glossy privet (Ligustrum lucidum), and the Siberian elm (Ulmus pumila). In field trapping experiments a Soxhlet extract of castor bean leaves caught more beetles than the optimal sex lure blend [(R)-(?)-linalool and (L)-isoleucine methyl ester blended in a ratio of 1:4], compared at equal doses (500 μl), and laboratory bioassays indicated that a castor bean plant could enhance the attractiveness of different blend ratios of sex lures. Olfactometer bioassays showed that males prefer volatiles emitted from different combinations of castor bean plant extracts and a signaling female over a female alone. In the presence of castor bean plants copulation rates of H. parallela were highest among all test environments both in laboratory bioassays (60%) and in field tests (70%). This study, combined with our previous observation of the feeding behavior of H. parallela adults on castor bean leaves, suggests that castor bean plants may provide an attractive but risky mating site for H. parallela beetles. The enhancement of male mate-location and copulation rate in the presence of castor bean plants can balance its paralytic effects on H. parallela after intake of potential toxins contained in its leaves.