330 g/L二甲戊灵乳油防除韭菜田杂草试验

为了确定330 g/L二甲戊灵EC能安全有效控制韭菜田杂草的用量,采用播后苗期施药,研究其在施后15、30、45 d对韭菜田旱稗、马唐等杂草的防治效果。试验结果表明,药后45 d,试验药剂495~742.5 g/hm2(有效成分用量)对旱稗、马唐、狗尾草、野苋、藜的最终株防效和鲜质量防效分别为96.97%~99.95%、97.86%~99.95%,96.46%~100%、96.78%~100%,92.51%~98.91%、94.06%~98.88%,54.51%~70.30%、58.69%~77.29%,55.82%~68.72%、72.64%~82.78%。药后10~30 d观察结果表明,试验药剂处理土壤对韭菜安全。     

非选择性除草剂Basta对荞麦和莜麦种子萌发的影响

应用植物组织培养技术 ,研究了不同浓度的除草剂Basta对单子叶植物莜麦和双子叶植物荞麦种子萌发和生长的作用 ;应用高温高压灭菌法和过滤灭菌法对Basta进行了处理 ,比较了二者之间的灭菌效果。结果表明 ,当培养基中Basta的浓度超过 4mg·L- 1时 ,可有效杀灭荞麦的种苗 ,而对莜麦种苗的有效作用浓度为 6mg·L- 1以上。高温高压灭菌不会造成Basta的分解和杀灭效果的减弱。     

新型玉米除草剂的防效与评价研究

为了筛选既对玉米生长无明显影响又能有效防除玉米地杂草的新型除草剂,2005-2006年对宝玉、玉邦和金玉黄龙3种除草剂进行了药剂试验,结果表明,玉邦除草剂用于苗前和苗后玉米4~8叶期、杂草2~4叶期防除杂草均有很好的防效,3种除草剂对杂草防效的排序为:玉邦>宝玉>金玉黄龙。     

小麦品种对绿麦隆反应敏感性的遗传研究

本研究以对绿麦隆反应敏感的苏麦3号、望水白及宁7840和不敏感的宁麦6号及扬麦5号五个小麦品种为亲本,在冷温室内、在有效用药量为0.15克/米~2的条件下,观察了绿麦隆对亲本、F_1及部分 F_2和回交后代苗期表现的影响。结果表明,对绿麦隆反应的敏感性的差异受一对基因控制,敏感为隐性,不敏感为显性。建议把苏麦3号和望水白中的     

Microbial and microfaunal community structure in cropping systems with genetically modified plants

Soils from field sites at Foulum (DK), Narbons (FR) and Varois (FR) planted with genetically modified maize expressing either the insecticidal Bacillus thuringiensis protein (Bt) or herbicide tolerance (HT), as described elsewhere in this volume, were analysed for nematodes, protozoa and microbial community structure. These analyses were mirrored in single-species testing and in mesocosm experiments, and were coordinated with field samples taken for microarthropods, enchytraeids and earthworms so allowing for cross-comparison and a better understanding of the results observed in the field. Over the first 2 years of the field experiments (in 2002 and 2003), the effect of Bt-maize was within the normal variation expected in these agricultural systems. Sampling in 2004 and 2005 was expanded to include the effects of tillage (i.e. reduced tillage versus conventional tillage) and also the use of HT-maize. Tillage had major effects regardless of soil type (Varois or Foulum), with reduced-tillage plots having a greater abundance of microfauna and a different microbial community structure (measured both by phospholipid fatty-acid analysis (PLFA) and by community-level physiological profiling (CLPP)) from conventionally tilled plots. Grass, as a contrasting cropping system to maize, also had an effect regardless of soil type and resulted in greater microfaunal abundance and an altered microbial community structure. Differences in crop management, which for the Bt-maize was removal of the insecticide used to control European corn borer and for HT-maize was a change in herbicide formulation, were only tested at single sites. There were differences in microbial community structure (CLPP but not PLFA) and sporadic increases in protozoan abundance under the Bt-crop management. The HT-maize cropping system, which covered a shorter period and only one site, showed little change from the conventional system other than an altered microbial community structure (as measured by PLFA only) at the final harvest. The Bt-trait had a minimal impact, with fewer amoebae at Foulum in May 2003, fewer nematodes at Foulum in May 2004 but more protozoa at Varois in October 2002 and an altered microbial community structure (PLFA) at Foulum in August 2005. These were not persistent effects and could not be distinguished from varietal effects. Based on the field evaluations of microfauna and microorganisms, we conclude that there were no soil ecological consequences for these communities associated with the use of Bt- or HT-maize in place of conventional varieties. Other land management options, such as tillage, crop type and pest management regime, had significantly larger effects on the biology of the soil than the type of maize grown.     

Interactions between 14C-labelled atrazine and the soil microbial biomass in relation to herbicide degradation

A laboratory incubation experiment was set up to determine the effects of atrazine herbicide on the size and activity of the soil microbial biomass. This experiment was of a factorial design (0, 5, and 50 g g^–1 soil of non-labelled atrazine and 6.6×10³ Bq g^–1 soil of ¹⁴C-labelled atrazine) x (0, 20, and 100 g g^–1 soil of urea-N) x (pasture or arable soil with a previous history of atrazine application). Microbial biomass, measured by substrate-induced respiration and the fumigation-incubation method, basal respiration, incorporation of ¹⁴C into the microbial biomass, degradation of atrazine, and ¹⁴C remaining in soil were monitored over 81 days. The amount of microbial biomass was unaffected by atrazine although atrazine caused a significant enhancement of CO₂ release in the non-fumigated controls. Generally, the amounts of atrazine incorporated into the microbial biomass were negligible, indicating that microbial incorporation of C from atrazine is not an important mechanism of herbicide breakdown. Depending on the type of soil and the rate of atrazine application, 18–65% of atrazine was degraded by the end of the experiment. Although the pasture soil had twice the amount of microbial biomass as the arable soil, and the addition of urea approximately doubled the microbial biomass, this did not significantly enhance the degradation of atrazine. This suggests that degradation of atrazine is largely independent of the size of the microbial biomass and suggests that other factors (e.g., solubility, chemical hydrolysis) regulate atrazine breakdown. A separate experiment conducted to determine total amounts of ¹⁴C-labelled atrazine converted into CO₂ by pasture and arable soils showed that less than 25% of the added ¹⁴C-labelled atrazine was oxidised to ¹⁴CO₂ during a 15-week period. The rate of degradation was significantly greater in the arable soil at 24%, compared to 18% in the pasture soil. This indicates that soil microbes with previous exposure to atrazine can degrade the applied atrazine at a faster rate.     

Environmental impacts from herbicide tolerant canola production in Western Canada

The commercial production of herbicide tolerant (HT) canola began in Western Canada in 1997. With more than a decade of use, the actual farm-level environmental impact of HT canola can be evaluated. This article reports on a spring 2007 survey of nearly 600 canola farmers in the three prairie provinces of Western Canada. Producers were asked about their crop production experiences for 2005 and 2006 and expected crop planting for 2007. A reduction in the total number of chemical applications over the 3-year period was reported, resulting in a decrease of herbicide active ingredient being applied to farmland in Western Canada of nearly 1.3 million kg annually. Fewer tillage passes over the survey period were reported, improving moisture conservation, decreasing soil erosion and contributing to carbon sequestration in annual cropland. An estimated 1 million tonnes of carbon is either sequestered or no longer released under land management facilitated by HT canola production, as compared to 1995. The value of this carbon off-set is estimated to be C$5 million. Comparisons with similar studies and against non-adoption of HT canola can guide future decisions about HT canola adoption.     

Management of cruciferous cover crops by mowing for soil and water conservation in southern Spain

In recent years, the use of cover crops in Mediterranean olive orchards has increased due to serious soil erosion problems and surface water contamination by herbicides. In these areas, the annual precipitation regime is strongly seasonal, with dry summers that require killing the cover crop before it competes with the trees for water. Cruciferous species are being introduced as cover crops in southern Spain, and their management by mowing could reduce the use of herbicides. However, the use of mowing as a management system requires an understanding of the phenology of these species to identify the most suitable mowing date to derive the greatest possible soil water content. The aims of this study were the following: (1) to assess the susceptibility of cruciferous species to mowing, their regrowth ability and the persistence of their residues on the soil surface after mowing, and (2) to identify the best mowing date for the cover crops in relation to the soil moisture content in the environmental conditions of southern Spain. For these purposes, the emergence, ground cover, biomass and regrowth after two mowing dates of common mustard (Sinapis alba L. subsp. mairei), rocket (Eruca vesicaria), radish (Raphanus sativus) and Ethiopian mustard (Brassica carinata) were evaluated in field trials during 2001/2002. In addition, during 2002/2003 and 2003/2004, the moisture content of soil sowed with common mustard and rocket cover crops was assessed at different mowing dates and compared with a bare soil control. Common mustard was the most favourable species for management by mowing due to its lack of regrowth after mowing. Early mowing (March 10th) reduced soil moisture due to the regrowth of the cover crop, fast decomposition of cover residues and weed proliferation. Late mowing (April 24th) led to little or no regrowth of the cover crops, large biomass and high persistence of cover residues, which provided effective soil ground cover, avoided the emergence of spring-summer weeds and helped retain soil moisture, reaching a similar water content to bare soil. These results suggest that cruciferous cover crops killed by mowing in late April can be used to replace no-tillage bare soil management systems to reduce the use of herbicides and preserve soil and water quality.     

玉米抗除草剂体细胞变异体的筛选及植株再生

将玉米优良自交系齐 31 9和N1 0 - 6产生的胚性愈伤组织 ,转移到加有半致死浓度除草剂绿磺隆的培养基上 ,经 3代筛选 ,获得抗除草剂愈伤组织。在加有除草剂的分化培养基上 ,抗性愈伤组织分化出植株。除草剂对愈伤组织的生长与分化有显著影响。再生植株移栽成活后 ,自交结实 ,获得种子。再生植株农艺性状与对照相似。除草剂抗性鉴定结果表明 ,再生植株及其后代对除草剂绿黄隆的抗性有了明显提高