烟蒜轮作与套作对土壤农化性状及烤烟产量的影响

为了探讨烟蒜轮作与套作对土壤农化性状及烤烟产量的影响,本试验在烤烟不同生育时期,采取单作烤烟、烟蒜轮作与套作种植方式下的土壤样品分析农化指标和统计烟叶产量,并对其结果进行对比分析.结果表明随生育期的推进,不同种植方式下根际土壤pH值呈增加趋势,烟蒜轮作与套作根际与非根际土壤的pH值均高于单作烤烟.上部叶成熟期,烟蒜轮作与套作根际与非根际土壤有机质含量均高于单作烤烟.下部叶与上部叶成熟期,烟蒜轮作与套作非根际土壤速效氮含量显著高于单作烤烟.而上部叶成熟期,烟蒜轮作与套作处理根际土壤速效磷、速效钾含量高于单作烤烟.烟蒜轮作与套作烟叶产量、上中等烟率较单作烤烟提高了35.04％和17.55％、5.88％和3.88％.烟蒜轮作与烟蒜套作种植方式均有利于缓解烟草连作障碍,改善土壤微生态环境,提高烤烟产量,但烟蒜轮作对其效果更加突出.本研究探讨烟蒜轮作与烟蒜套作种植方式对土壤农化性状及烤烟产量的影响,可为改良植烟土壤、减轻连作障碍及栽培制度的创新提供理论基础和技术支撑.     

Vectorizing agrochemicals: enhancing bioavailability via carrier‐mediated transport

Systemicity of agrochemicals is an advantageous property for controlling phloem sucking insects, as well as pathogens and pests not accessible to contact products. After the penetration of the cuticle, the plasma membrane constitutes the main barrier to the entry of an agrochemical into the sap flow. The current strategy for developing systemic agrochemicals is to optimize the physicochemical properties of the molecules so that they can cross the plasma membrane by simple diffusion or ion trapping mechanisms. The main problem with current systemic compounds is that they move everywhere within the plant, and this non‐controlled mobility results in the contamination of the plant parts consumed by vertebrates and pollinators. To achieve the site‐targeted distribution of agrochemicals, a carrier‐mediated propesticide strategy is proposed in this review. After conjugating a non‐systemic agrochemical with a nutrient (α‐amino acids or sugars), the resulting conjugate may be actively transported across the plasma membrane by nutrient‐specific carriers. By applying this strategy, non‐systemic active ingredients are expected to be delivered into the target organs of young plants, thus avoiding or minimizing subsequent undesirable redistribution. The development of this innovative strategy presents many challenges, but opens up a wide range of exciting possibilities. © 2018 Society of Chemical Industry     

同位素示踪法在磺酰脲类除草剂残留分析中的应用

除草剂的同位素残留分析技术日益受到人们的重视,并取得了长足的发展。本文综述了利用同位素示踪技术对4种磺酰脲类除草剂的残留分析进展。     

化肥替代型和环境友好型农业技术市场形成的内在机理

本文在分析国内外化肥产业政策及其环境影响的基础上,从农户的技术需求行为和研发机构的技术供给行为两个方面从微观角度探讨了化肥替代型和环境友好型农业技术市场形成的内在机理,提出了推动化肥替代型和环境友好型农业技术发展的对策和建议,旨在探询我国化肥产业政策调整的理论依据并促进我国农业生产向着环境友好、科学可持续的现代农业方向发展.     

Verbesserungsvorschlag zur gefahrlosen Beheizung brennbarer Lösungsmittel zur Fettextraktion (Kurzmitteilung)

A crop rotation field study with manure application was established at Tartu in 1985. Biological and chemical properties were evaluated on fine sandy loam Podzoluvisol in May 1989. The treatments included unmanured (N_o and N₈₀) controls, two peat based composts and five manures of different origin. The procedures of the most probable number (MPN) and spread plate counts were used for microbiological investigation, but also enzymatic activities, nitrogen forms, total‐C and pH were simultaneously estimated in plough layer soil. The most variable i.e. the most clearly differentiated physiological groups within manures were cellulolytic and ammonifying bacteria followed by Azotobacter spp. together with actinomycetes. Abundance of aerobic cellulolytic and ammonifying bacteria correlated positively with the number of soil algae and fungi, and negatively with nitrate‐ and nitrite‐reductase. The number of actinomycetes correlated positively with urease and catalase activity. Soil enzymatic activity was mainly modified by nitrite‐reductase. Peat composts had the highest C‐content and highest pH value compared with other soils. Pig slurry and NH₄NO₃ (N80) treatment had the highest level of fixed NH⁺ ₄ ‐ions in soil. Nine months after manure application no differences were found in the unstable NO^– ₃content of soil. Variation in the number of the studied microbial physiological groups between treatments remained insignificant.     

Impacts of Municipal Wastewater on The Transport Characteristics of Reactive Solutes Through Agricultural Soils

Reliable transport parameters of agrochemicals and soluble pollutants are crucial for modeling and management of soil and groundwater quality. This study investigated impacts of municipal wastewater on the transport parameters of five heavy metal/metalloid compounds (NaAsO₂, Cd(NO₃)₂, Pb(NO₃)₂, Ni(NO₃)₂ & ZnCl₂), two pesticides (cartap & carbendazim) and an inert salt (CaCl₂) in four agricultural soils of Bangladesh. Solute-breakthrough concentrations were measured in repacked soil columns with time-domain reflectometry (TDR) both before and after wastewater treatment. Transport velocity (V), dispersion coefficient (D), dispersivity (λ) and retardation factor (R) of the solutes, and pertinent soil properties were determined. Wastewater reduced bulk density (γ) of the soils (from 1.32–1.37 g/cm³ to 1.26–1.35 g/cm³) by increasing organic carbon (OC) (from 0.37%–0.84% to 0.40–0.93%), increased pore-size distribution index (n) (by 0.02 unit) and reduced soil pH (from 6.32–7.45 to 5.92–6.46). D and λ decreased while V and R increased after wastewater treatment; D decreased and R increased linearly with decreasing bulk density. The correlations of V, D, and R with n improved significantly (p < 0.05) after wastewater treatment. The correlation between λ and OC improved markedly for Ca, Pb, Ni, and cartap. The observed indicative results have practical implications in developing pedo-transfer functions for solute-transport parameters using basic soil properties, which are subject to progressive modification due to agrochemicals application and wastewater irrigation.     

Opportunities for chiral agrochemicals

Chiral compounds account for 25% of all agrochemical compounds used commercially and for 26% of the total value of the world agrochemical market. However, those sold in single isomer form contribute only 7% to the market value despite many potential advantages in terms of regulatory, intellectual property and marketing benefits. Limited access to chiral raw materials and economic synthesis routes are key reasons why single isomers are less common than they might be. The development of more chiral routes will encourage the development of single isomer compounds to capitalise on their advantages.     

海洋弗氏链霉菌HNM0089抗真菌活性成分研究

为了从海洋微生物中寻找农药先导化合物,本研究通过16S rRNA基因序列分析对具有抗真菌活性的海洋放线菌HNM0089的种属进行鉴定,并对其抗真菌的活性成分进行研究。结果表明:海洋放线菌HNM0089被鉴定为弗氏链霉菌(Streptomyces fradiae)。利用高分辨质谱、一维和二维核磁波谱技术,将其主要活性成分鉴定为星形孢菌素(Staurosporine)。该化合物对芒果炭疽病菌、水稻稻瘟病菌、香蕉枯萎病菌、薯蓣炭疽病菌和橡胶炭疽病菌均有抑制活性,具有开发成农用抗菌素的潜力。     

Agrochemical industry development,trends in R&D and the impact of regulation

Over the last 20 years the share of the crop protection market attributable to the leading markets (North America, EU‐15 and Japan) that are the major focus of new active ingredient research and development (R&D) has declined. Greater growth has been recorded in developing markets, questioning the focus of current R&D strategy. R&D budgets within the major companies have seen a shift toward genetically modified (GM) trait development away from agrochemicals, such that the rate of new active ingredients entering development and subsequently being introduced has declined. As a result, the industry has become more reliant on older, off‐patent chemistry, although the availability of older products has been affected by re‐registration requirements, particularly in the EU. Current criteria often preclude the registration of broad‐spectrum agrochemicals, resulting in many new active ingredients being single site active, which is perceived to increase the potential for resistance development, particularly for herbicides, although this is not always the case. © 2019 The Author. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.