优质日光温室黄瓜新品种中农26号的选育

中农26号是以01316为母本和04348为父本配制而成的黄瓜一代杂种。瓜色深绿,腰瓜长约30 cm,瓜把短,心腔小,果肉绿色,商品瓜率高;综合抗病性强,抗霜霉病、白粉病、病毒病,中杭枯萎病;耐低温弱光;持续结瓜及丰产优势明显。早春日光温室栽培产量高达8 900 kg·（667 m²）^-1。适宜北方日光温室各茬口栽培。     

基于工控机的汽车主锥预紧力测量机控制系统设计

该文分析了汽车主锥中圆锥滚子轴承的预紧力与轴向位移、压紧轴承的锁紧螺母拧紧力矩之间的关系,以及轴向位移量与启动摩擦力矩之间的内在联系,并研制出具有锁紧螺母预紧力矩和轴承启动摩擦力矩自动测量功能的主锥自动装配设备的控制系统。该系统以工控机为控制核心,以Visual C++作为软件开发工具,使系统既具有较高的稳定性及灵活性,又有直观、友好用户界面。控制系统对锁紧螺母拧紧力矩和轴承摩擦力矩采用闭环控制的实时测量,可精确控制轴承的预紧力,提高主锥总成的装配质量和生产效率。     

The economics of soil productivity: local,national and global perspectives

Soil degradation is a mounting problem on many smallholder lands in developing countries. Economic analysis has been an important tool in addressing this problem, beginning with assessments of the financial attractiveness of investing in soil conservation works. Data compiled from 67 studies of the financial attractiveness of conservation technologies suggest that many can provide positive net returns at the farm level (64·2 per cent). While such studies have made a valuable contribution, economists have been exploring additional applications of economics to the problem, such as the development of new perspectives under the guise of ecological economics. As a result, this paper argues it is an opportune time to assess progress in the field of economic analysis of soil degradation and to consider the policy ramifications of this research. Key issues are grouped into farm‐level considerations, national policy linkages and global issues. A number of policy implications emerge. Clearly, devising effective incentives at the farm or community (collective action) level must be a priority. As part of this effort, even more attention should be paid to the influence of macroeconomic and sectoral policies on soil productivity. Since soil degradation is also a problem with global ramifications, there is a clear rationale for intervention at the international level via mechanisms such as international transfers. Copyright © 2004 John Wiley & Sons, Ltd.     

The effect of initial concentration of carbofuran on the development and stability of its enhanced biodegradation in top‐soil and sub‐soil

Carbofuran was incubated in top‐soil and sub‐soil samples from a pesticide‐free site at a range of initial concentrations from 0.1 to 10 mg kg⁻¹. Amounts of the incubated soils were removed at intervals over the subsequent 12 months, and the rate of degradation of a second carbofuran dose at 10 mg kg⁻¹ was assessed. An applied concentration as low as 0.1 mg kg⁻¹ to top‐soil resulted in more rapid degradation of the fresh addition of carbofuran for at least 12 months. The degree of enhancement was generally more pronounced with the higher initial concentrations. When the same study was conducted in sub‐soil samples from the same site, an initial dose of carbofuran at 0.1 mg kg⁻¹ resulted in only small increases in rates of degradation of a second carbofuran dose. However, degradation rates in the sub‐soil samples were, in many instances, considerably greater than in the corresponding top‐soil samples, irrespective of pre‐treatment concentration or pre‐incubation period. Initial doses of 0.5 mg kg⁻¹ and higher applied to sub‐soil successfully activated the sub‐soil microflora. Application of the VARLEACH model to simulate carbofuran movement through the soil profile indicated that approximately 0.01 mg kg⁻¹ of carbofuran may reach a depth of 70 cm 400 days after a standard field application. The results therefore imply that adaptation of the sub‐soil microflora (c 1 m depth) by normal field rate applications of carbofuran is unlikely to occur. In experiments to investigate this in soils exposed to carbofuran in the field, there was no apparent relationship between top‐soil exposure and degradation rates in the corresponding sub‐soils. The results further confirmed that some sub‐soil samples have an inherent capacity for rapid biodegradation of carbofuran. The high levels of variability observed between replicates in some of the sub‐soil samples were attributed to the uneven distribution of a low population of carbofuran‐degrading micro‐organisms in sub‐surface soil. There was no apparent relationship between soil microbial biomass and degradation rates within or between top‐soil and sub‐soil samples. © 2001 Society of Chemical Industry     

早中熟大白菜新品种京秋黄心70的选育

京秋黄心70系由两个自交不亲和系99550和98236配制而成的秋早中熟大白菜一代杂种。早中熟,播种后65～70 d（天）收获。株型直立,生长势强,高抗病毒病,抗霜霉病和黑腐病,叶球顶部舒心,叶球长筒形,球内叶浅黄色,球高44 cm,球横径14 cm,单球质量2.5 kg,每667 m²净菜产量5 300 kg左右。已在北京、河北、天津、四川、江苏等地推广种植333 hm²。     

Swine Influenza in Sub‐Saharan Africa – Current Knowledge and Emerging Insights

Pigs have been associated with several episodes of influenza outbreaks in the past and are considered to play a significant role in the ecology of influenza virus. The recent 2009 pandemic influenza A/H1N1 virus originated from swine and not only did it cause widespread infection in humans, but was also transmitted back to swine in Asia, Europe and America. What may be the prevailing situation in Africa, particularly in sub‐Saharan Africa, with respect to the circulation of classical swine or pandemic influenza? The ecology of influenza viruses, as well as the epidemiology of human or animal influenza, is poorly understood in the region. In particular, little is known about swine influenza in Africa despite the relevance of this production in the continent and the widespread pig husbandry operations in urban and rural areas. In this review, the gap in the knowledge of classical and pandemic swine influenza is attributed to negligence of disease surveillance, as well as to the economic and public health impact that the disease may cause in sub‐Saharan Africa. However, emerging serological and virological evidence of swine influenza virus in some countries in the region underscores the importance of integrated surveillance to better understand the circulation and epidemiology of swine influenza, a disease of global economic and public health importance.     

Impact of sub-lethal residues of azinphos-methyl on the pheromone-communication systems of insecticide-susceptible and insecticide-resistant obliquebanded leafrollers Choristoneura rosaceana (Lepidoptera: Tortricidae)

The effects of sub-lethal residues of azinphos-methyl on pheromone production, calling, female attractiveness and the ability of males to locate sources of natural and synthetic pheromone were compared in azinphos-methyl-susceptible (susceptible) and azinphos-methyl-resistant (resistant) obliquebanded leafrollers, Choristoneura rosaceana (Harris). The amount of pheromone in susceptible females was reduced by 29-33% after exposure to azinphos-methyl; this treatment did not affect the pheromone content of resistant females. Azinphos-methyl-treated resistant females contained 39-43% less pheromone than azinphos-methyl-treated susceptible females. Resistant females that were not treated with azinphos-methyl contained 35-56% less pheromone than susceptible females that were not treated with insecticide. The incidence of calling was reduced by 67-100% in azinphos-methyl-treated susceptible females; the incidence of calling by resistant females was not affected by exposure to azinphos-methyl. The incidence of calling by azinphos-methyl-treated susceptible females was 58-100% lower than that of azinphos-methyl-treated resistant females. There was no difference in the incidence of calling between susceptible and resistant females that had not been treated with insecticide. In a flight tunnel, treatment with insecticide reduced the attractiveness of susceptible females by 38%; treatment with insecticide did not affect the attractiveness of resistant females. There was no difference in the proportion of males attracted to susceptible and resistant females that had, or had not been treated with insecticide. In an apple orchard, the attractiveness of susceptible and resistant females treated with azinphos-methyl was reduced by 84 and 12%, respectively. The proportion of males attracted to azinphos-methyl-treated susceptible females was 58% lower than the proportion attracted to azinphos-methyl-treated resistant females, whereas, if females were not treated with insecticide, the proportion attracted to resistant females was 57% lower than the proportion attracted to susceptible females. In a flight tunnel, azinphos-methyl did not affect the ability of susceptible or resistant males to locate a source of pheromone gland extract. Likewise, in an apple orchard, the insecticide treatment had no effect on the ability of susceptible or resistant males to locate a source of synthetic pheromone. In a flight tunnel, there was no difference in the proportion of azinphos-methyl-treated susceptible and resistant males locating a source of pheromone gland extract; however, in the orchard, 39% fewer azinphos-methyl-treated resistant males located a source of synthetic pheromone than azinphos-methyl-treated susceptible males. A similar proportion of susceptible and resistant males that had not been treated with insecticide located a source of pheromone gland extract in the flight tunnel, but in the orchard, the proportion of resistant males not treated with azinphos-methyl that located the source of synthetic pheromone was 32% lower than the proportion of susceptible males not treated with this insecticide. The implications of the differences in the effect of sub-lethal residues of azinphos-methyl on the pheromone communication system of susceptible and resistant moths are discussed in relation to the theory of the development of insecticide resistance, the detection of resistance in feral populations of moths using sex pheromone-baited traps, and the control of moths using sex pheromone-mediated mating disruption.     

Carbon dioxide flux and soil carbon stock as affected by crop residue management and soil texture in semi‐arid maize croplands in Tanzania

Crop residue management strategies must be adapted for improving carbon (C) balance and soil C stock in agroecosystems in sub‐Saharan Africa with consideration of the crop residue availability and site‐specific soil characteristics. We conducted field experiments to determine the effects of crop residue application method (incorporation/mulching) and quality (maize/cowpea) and N fertilizer application on the soil respiration rate and soil C stock in the surface soil layer (0–15 cm) in maize croplands with contrasting soil textures (clay/sandy) over 2 years from 2012 to 2014 in Tanzania. At the clay site, the incorporation of maize residues showed a 38% increase in CO₂ flux compared to mulching, whereas, at the sandy site, mulching showed a 16% increase compared to the incorporation. At the sandy site, mulching practice retained soil moisture content and apparently enhanced the decomposition of the original soil organic C in the surface layer. It is, therefore, suggested that mulching practice may accelerate a long‐term depletion of soil C stock at the sandy site. The cowpea residue incorporation led to rapid decomposition because of its high biodegradability at both sites. The N fertilizer application stimulated the decomposition of labile soil organic matter. The soil C stock in the surface layer did not significantly change after the 2‐year experiment, irrespective of crop residue treatment and soil type. In conclusion, adequate crop residue management in terms of suppressing CO₂ flux during a cropping season depends on soil type, but the long‐term effect on soil C stock is unclear.     

辣椒新品种京辣8号的选育

京辣8号是以优良辣椒自交系04-60为母本，以甜椒自交系04-136为父本配制而成的中早熟辣椒一代杂种。中早熟，持续坐果能力强，整个生长季果形保持良好。果实短锥牛角形，以2～3心室为主，青熟果翠绿色，果面光滑。果实纵径约16 cm，横径约5.6 cm，肉厚约0.4 cm，单果质量90～150 g。抗TMV，中抗CMV，对疫病的耐性与对照湘研13号相当。每667 m²产量3 500 kg左右，适于长江流域春秋及秋延后大棚、小拱棚种植。     

Soil carbon sequestration in sub‐Saharan Africa: a review

Restoration of degraded soils is a development strategy to reduce desertification, soil erosion and environmental degradation, and alleviate chronic food shortages with great potential in sub‐Saharan Africa (SSA). Further, it has the potential to provide terrestrial sinks of carbon (C) and reduce the rate of enrichment of atmospheric CO₂. Soil organic carbon (SOC) contents decrease by 0 to 63 per cent following deforestation. There exists a high potential for increasing SOC through establishment of natural or improved fallow systems (agroforestry) with attainable rates of C sequestration in the range of 0·1 to 5·3 Mg C ha⁻¹ yr⁻¹. Biomass burning significantly reduces SOC in the upper few centimeters of soil, but has little impact below 10 to 20 cm depth. The timing of burning is also important, and periods with large amounts of biomass available generally have the largest losses of SOC. In cultivated areas, the addition of manure in combination with crop residues and no‐till show similar rates of attainable C sequestration (0 to 0·36 Mg C ha⁻¹ yr⁻¹). Attainable rates of SOC sequestration on permanent cropland in SSA under improved cultivation systems (e.g. no‐till) range from 0·2 to 1·5 Tg C yr⁻¹, while attainable rates under fallow systems are 0·4 to 18·5 Tg C yr⁻¹. Fallow systems generally have the highest potential for SOC sequestration in SSA with rates up to 28·5 Tg C yr⁻¹. Copyright © 2005 John Wiley & Sons, Ltd.