低定量环保型水稻秸秆纤维地膜制造工艺参数优化

为解决中国农业生产中化肥农药长期不合理的施用、秸秆和土壤中残膜等农业废弃物不合理的处置等农业面源严重污染的问题,为降低生物质基降解地膜的生产成本、节约纤维用量,探究低定量环保型可降解纤维地膜制造工艺参数的最优组合,对55 g/m2低定量环保型水稻秸秆纤维地膜的工艺及性能进行了试验研究。以水稻秸秆纤维为主要原料,添加商品浆、功能助剂等,应用五因素五水平1/2实施正交旋转中心组合试验方法,以打浆度、混合比、松香、矾土和湿强剂质量分数为影响因子,以地膜的干抗张力、湿抗张力、耐破度为响应函数,研究得出了打浆度31°～48°、混合比45%～50%、松香质量分数1.2%、矾土质量分数6%、湿强剂质量分数2.0%的低定量环保型水稻秸秆纤维地膜最佳工艺参数组合,所得纤维地膜的干抗张力大于32 N、湿抗张力大于12 N、耐破度大于100 kPa,可满足地膜田间覆盖机械性能要求。研究结果为水稻秸秆制备可降解地膜提供理论依据和技术支撑。     

水稻秸秆纤维地膜制造工艺参数优化

为规模化生产与塑料地膜除草和保墒等同、价格相当的生物质基生物降解地膜提供技术支撑,该文对用水稻秸秆纤维制取地膜的工艺进行了探讨。以水稻秸秆纤维为主要原料,添加KP浆板（木材纤维）、湿强剂、松香以及矾土等环保助剂,利用常规抄纸工艺,采用五因素五水平1/2实施正交旋转中心组合试验设计的方法,以打浆度、混合比、定量、湿强剂、调节剂为影响因素,选取干抗张力、湿抗张力、施胶度为性能指标,进行了试验研究。研究结果表明：在定量90 g/m2,调节剂0.2%,湿强剂0.8%,混合比低于 68%,打浆度大于45°SR的参数组合下,水稻秸秆纤维地膜的干抗张力大于30 N,湿抗张力大于10 N,施胶度大于100 s。优化后的参数可满足地膜田间覆盖机械性能要求。     

可降解地膜原料大豆秸秆纤维的制备工艺及参数优化

为了解决秸秆和塑料地膜带来的环境污染问题,高值化利用秸秆资源。该研究采用二次正交旋转中心组合试验方法,探索运用物理方法制取清洁、高强度、高得率的可生物降解地膜原料-大豆秸秆纤维的可行性,寻求物料特性和工作参数对制取大豆秸秆纤维的影响规律和最优工艺参数组合。分别选取大豆秸秆长度、浸泡时间、加工温度、主轴转速和喂入量为影响因素,纤维得率、纤维长宽比及抗张强度为响应函数,应用Design-expert6.0.10软件设计方案与数据分析。试验结果表明:当参数组合为秸秆长度7cm、浸泡时间24h、喂入量27g/min、工作温度80～85℃、转速110～120r/min时,制得的大豆秸秆纤维得率大于80%、干抗张强度大于7N、长宽比大于5;各因素对纤维得率贡献率的主次关系为:浸泡时间>主轴转速>喂入量>秸秆长度>加工温度,各因素对干抗张强度贡献率的主次关系为:秸秆长度>加工温度>喂入量>浸泡时间>主轴转速,各因素对纤维长宽比贡献率的主次关系为:喂入量>秸秆长度>加工温度>浸泡时间>主轴转速。为利用大豆秸秆制备可降解地膜提供理论依据和技术支撑。     

废旧棉与水稻秸秆纤维混合地膜制造工艺参数优化

为提高废旧棉织物和农作物秸秆的利用率,对废旧棉纤维与水稻秸秆纤维混合制取地膜的工艺及性能进行了试验研究。以废旧棉纤维为"骨架",水稻秸秆纤维为填充辅料,添加功能助剂,应用四因素五水平二次正交旋转中心组合试验方法,以打浆度、棉纤维添加量、定量和湿强剂质量分数为影响因子,以混合地膜的干抗张强度、干伸长率、湿抗张强度、湿伸长率为响应函数,研究得出了定量77~90 g/m2、湿强剂质量分数1.5%~1.8%、棉纤维打浆度45°SR、棉纤维添加量25%的废旧棉与水稻秸秆纤维混合地膜最佳工艺参数组合,所得混合纤维地膜的干抗张强度大于32 N、干伸长率大于1.8%、湿抗张强度大于10 N、湿伸长率大于5.5%,可满足地膜田间覆盖机械性能要求。研究结果为综合利用废旧棉织物和水稻秸秆制备可降解地膜提供理论依据和技术支撑。     

水稻秸秆纤维制取工艺参数优化

采用五因素二次回归正交旋转中心组合设计试验方法,以秸秆长度、浸泡时间、套筒初始温度、主轴转速和喂入量为影响因子,以纤维得率、纤维长宽比和抗张指数为响应函数,利用秸秆纤维制取专用试验台,对水稻秸秆纤维制取工艺进行了试验研究,得到了工艺优化参数组合：当套筒初始温度为25℃、主轴转速为70 r/min、喂入量为60 g/min、秸秆长度为10～14 cm和浸泡时间为12～24 h时,可得到纤维得率大于85%、长宽比大于40并且抗张指数大于10 N?m/g、的水稻秸秆纤维。     

用于地膜原料的大豆秸秆粉碎预处理工艺参数优化

为了满足植物纤维制取机对大豆秸秆原料长度的要求,采用改进的揉切式粉碎机对大豆秸秆进行预处理,选取揉切机的主轴转速、喂入量以及秸秆的含水率为试验因素,以大豆秸秆粉碎长度为响应函数,对大豆秸秆原料的预处理工艺参数进行了组合试验研究。结果表明:1)各因素对于秸秆粉碎长度影响的贡献率从高到低排序为主轴转速、含水率和喂入量;2)预处理工艺的最优参数组合为喂入量168 kg/h、大豆秸秆含水率处于36%~58%、揉切机主轴转速处于1 100~1 300 r/min。在此工艺参数条件下,大豆秸秆粉碎长度分布符合植物纤维制取机所要求的70~85 mm的理想范围。研究结果为完善植物纤维地膜制造工艺体系提供了参考。     

水稻秸秆纤维基绿色地膜制造工艺参数优化

为改善水稻秸秆纤维基地膜的增温性,该文研究了将水稻秸秆纤维基地膜由本色的乳白色改性为绿色的工艺参数,阐明了主要影响因子对该染色地膜性能的影响规律。应用五因素五水平正交旋转中心组合的试验方法,研究以秸秆纤维浆、染料、染料中亮蓝占比、改性剂和湿强剂的质量分数对水稻秸秆纤维基地膜的透气度、上染率、褪色率、干抗张力及湿抗张力等诸多指标的影响。结果表明:当选取工艺参数组合为秸秆纤维浆质量分数71%~79%、染料质量分数0.44%~0.53%、染料中亮蓝占比90%、改性剂质量分数0.6%、湿强剂质量分数0.9%时,所得水稻秸秆纤维基绿色地膜的透气度≤2μm/Pa·s、上染率≥80%、褪色率≤8%、干抗张力≥40 N、湿抗张力≥16 N,可满足水稻秸秆纤维基地膜水、旱田覆盖栽培有机(绿色)作物技术要求。     

杀菌型水稻秸秆纤维基地膜制造工艺参数优化研究

为提高农药有效利用率、减少农药使用量,对负载广谱杀菌剂多菌灵的杀菌型水稻秸秆纤维基地膜制造工艺参数组合进行了优化研究。应用四因素五水平二次正交旋转中心组合试验方法,以湿强剂、施胶剂、胶黏剂浓度和涂层厚度为影响因子,选择杀菌型水稻秸秆纤维基地膜的干抗张力、湿抗张力、透气度、降解周期、农药有效利用率为响应函数,实施了组合试验,结果表明:当工艺参数组合为湿强剂质量分数0.8%～0.9%、施胶剂质量分数0.5%～0.7%、胶黏剂浓度2.0%、涂布厚度20μm时,杀菌型水稻秸秆纤维基地膜干抗张力≥35 N、湿抗张力≥15 N、透气度≤2μm/(Pa·s)、降解周期≥60 d、农药有效利用率≥80%。研究结果表明该地膜不仅提高了秸秆纤维基地膜的各项性能指标且增加了秸秆纤维基地膜的杀菌功能,而且为广谱杀菌剂多菌灵增效减量和广谱杀菌型水稻秸秆纤维基地膜的研发提供了参考依据。     

大豆秸秆纤维制造可降解地膜工艺参数优化

为了提高大豆秸秆的附加值和批量生产经济、满足农艺要求的环境友好型可降解大豆秸秆纤维基地膜,采用二次正交中心旋转组合试验,采用地膜定量、木浆混合比、松香、矾土和湿强剂为影响因素,地膜的干抗张强度和湿抗张强度作为响应函数。试验结果表明：1）各因素对干抗张强度的影响的贡献率从高到低排序为木浆混合比、定量、湿强剂、松香和矾土。2）各因素对湿抗张强度的贡献率从高到低排序为木浆混合比、定量、湿强剂、矾土和松香。3）按照干抗张强度≥30 N、湿抗张强度≥15 N的原则,在木浆混合比0～50%、定量50～110 g/m2、湿强剂1.2%～2%、松香0.3%～1.5%、矾土1%～5%的约束条件下,满足工艺要求的最优参数组合：木浆混合比23.3%～30%、定量92～110 g/m2、湿强剂1.2%、松香0.3%、矾土5%。按最优工艺混合比选取25%时,定量92 g/m2、湿强剂1.2%、松香0.3%、矾土5%制造出地膜试样,干抗张强度32.4 N,湿抗张强度15 N。     

秸秆热解工艺优化与生物炭理化特性分析

以肥料化利用为目标,优化秸秆热解工艺,实现秸秆生物炭的高值化利用。该研究以水稻、小麦、玉米、油菜和棉花秸秆为原料,以炭化温度、保温时间和升温速率为因素进行正交试验,采用综合评分法优化热解工艺,并分析最优工艺条件下生物炭的理化特性。结果表明,影响秸秆生物炭品质因素的主次顺序为炭化温度、保温时间、升温速率。以生物炭的肥料化利用为目标,5种秸秆炭化的最优工艺参数组合是炭化温度500℃、保温时间30 min、升温速率10℃/min。在最优工艺条件下,5种秸秆生物炭的炭产率约为32%~38%,固定碳的质量分数大于45%,C元素的质量分数大于53%,N元素的质量分数为0.7%~2.5%,K元素的质量分数为3.41%~6.81%。生物炭表面有含氧官能团且内部有丰富的介孔结构。该研究为秸秆生物炭的肥料化利用提供数据支撑。     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.     

细菌、真菌及植物氮营养信号研究进展

氮素吸收代谢是所有生物生命活动的核心部分,因此,各种生物对氮的吸收与同化过程都有精细的调节。这种调节依赖于生物对体内氮素状况信号及体外（生长介质中）氮素信号的感受。过去几十年中,在细菌、真菌中已经对氮素营养信号有了较好的研究,而植物中则相对缓慢,但也有了一定的认识。本文重点比较细菌、真菌及植物中氮信号系统的组成,以期为进一步认识植物中的氮信号接受与转导系统提供启示。     

Aircraft operations near concentrations of birds in Antarctica: The development of practical guidelines

Aircraft operations have the potential to disturb and to impact negatively on bird life. A gradient of increasing behavioural response is evident in birds when exposed to increasing aircraft stimulus. The most major disturbance is likely to lead to impacts on the health, breeding performance and survival of individual birds, and perhaps bird colonies. A process of revision to policies on aircraft operations contained in management plans for a number of specially protected areas in Antarctica by the United Kingdom, accompanied by consultations made within the scientific community through the Scientific Committee on Antarctic Research (SCAR) and with operational interests through the Council of Managers of National Antarctic Programmes (COMNAP) resulted in new guidelines being adopted by the Antarctic Treaty Consultative Parties in June 2004. The principal recommendations of the guidelines are that bird colonies should not be overflown below 2000 ft (∼610 m) above ground level and landings within 1/2 nautical mile (∼930 m) of bird colonies should be avoided wherever possible. These guidelines are less stringent and less specific than those that were recommended by the SCAR specialist group on birds, and represent a compromise to accommodate operational needs. While the adoption of clear and consistent guidelines for the operation of aircraft in Antarctica is welcome in that this provides practical advice that is likely to reduce incidences of close aircraft/bird encounters, there remains insufficient knowledge of the interactions between aircraft and birds in Antarctica, and the consequent impacts on individual birds and on bird populations. It is important, therefore, that the guidelines adopted are considered interim, and should be kept under scrutiny with revisions made as new and improved research results appear.     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.