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。     

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。     

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。     

小麦秸秆纤维地膜原料打浆工艺参数优化

为探索打浆工艺参数对小麦秸秆纤维地膜原料打浆后的浆料性能的影响,试验研究了工艺参数优化组合,阐明了主要影响因素的影响规律。该研究以浸泡水温、浸泡时间、打浆时间、打浆负荷、浆池水量为试验因素,以干抗张指数、打浆度和浆料纤维长度为性能指标,采用五因素五水平(1/2实施)二次回归正交旋转中心组合设计参数优化试验,得到了小麦秸秆纤维地膜原料最优打浆工艺参数组合。结果表明:工艺参数组合为浸泡水温63℃、浸泡时间2 h、浆池水量13.50 L、打浆负荷4.57～5.50 kg和打浆时间0.25～0.68 h时,小麦秸秆纤维地膜浆料的干抗张指数大于5 N·m/g、打浆度小于50°SR,浆料纤维长度大于0.9 mm,在此条件下加工的浆料可以制造出小麦秸秆纤维基植物纤维地膜,其可满足水、旱田覆盖栽培作物技术要求。研究结果可为小麦秸秆制备全降解植物纤维地膜提供理论依据和技术支撑。     

原位聚合法制备可降解纤维基地膜及机理分析

为提高农作物秸秆综合利用率，通过原位聚合法，以水稻秸秆作为纤维原料制备陇上覆盖方式的功能型可降解地膜。结果表明，改性后，秸秆纤维基地膜的干抗张力等物理力学性能得到提高。X射线衍射结果显示，改性后秸秆纤维基地膜的相对结晶度从38.11%提升到64.42%，说明功能型助剂可渗透到纤维素的无定形区内，使无定形区的微纤丝向结晶区靠拢引起细胞壁纤维素微纤丝结晶区的宽度增加。改性后秸秆纤维基地膜的接触角从95.35°提高到121.03°，表明改性后地膜的抗水性能提高，能较好的适应户外陇上覆盖要求。TG结果表明，改性后地膜的热稳定性能得到提高。FTIR谱图显示改性剂中的功能性基团与地膜中的纤维结构发生了化学交联反应。XPS结果表明，改性后的秸秆纤维基地膜氧与碳的原子浓度比增加，说明改性剂与地膜纤维发生化学交联反应从而含氧官能团增加。SEM-EDXA结果表明改性剂较好的分布在秸秆纤维基地膜中，有利于纤维的交联。烟草覆盖试验表明，秸秆纤维基地膜提高了烟草种植整体水平。因此，功能型秸秆纤维基地膜能未来可应用于烟草、大蒜、西红柿和水稻等高经济附加值作物，为农作物秸秆综合利用提供新的方向。     

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。     

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。     

水稻秸秆与木屑混合原料热压成型试验

为提高水稻秸秆原料成型燃料的质量,提出通过添加木质素含量较高的木屑原料即形成混合原料并通过试验的方法进行研究。首先进行对比试验,以成型燃料的物理性能为指标,在相同实验条件下对木屑、水稻秸秆和水稻秸秆与木屑1∶1混合的原料进行热压成型试验。对比试验的结果表明小压力下1∶1混合原料成型燃料的综合物理性能优于水稻秸秆成型燃料,证明混合原料可提高单一水稻秸秆原理成型燃料的质量。但由于木屑原料本身的结构特性使得1∶1混合原料成型燃料的抗渗水性较弱。因此为进一步提高混合原料成型燃料质量,我们利用正交试验方法研究对于混合原料成型燃料各物性指标而言最显著影响因素及最佳参数组合并通过试验加以论证。试验结果表明:针对不同性能指标,各工艺参数的影响力不一致,对于松弛密度、抗碎强度及抗压强度而言,压力对其影响较大;而对于抗渗水性而言,原料混合比影响较大。对于松弛密度,最佳成型参数(混合比、温度、压力)组合为0.5∶1,70℃、31.11 MPa,抗碎强度的成型参数最优组合为2∶1,110℃、31.11 MPa,抗渗水性和抗压强度的最佳成型参数组合为1.5∶1,90℃、31.11 MPa。     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

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.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications     

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.     

Collection and preliminary evaluation of native turfgrass accessions in Italy

Despite a raising interest on turfs in Italy, all theavailable varieties of this kind in the Country are of foreign origin, and areoften poorly adapted to the prevailing climatic conditions. This prompted tobegin a collection activity of indigenous turfgrass species, with the ultimategoal of identifying promising materials for future breeding based on localgenetic resources. The collection was carried out in three areas of Italy, viz.the northern Po Plain, the coastal region of Liguria, and the island of Sardiniathat are characterised, respectively, by subcontinental, warm temperate, andtypical Mediterranean climate. Altogether, 141 sites were visited, yielding 226accessions belonging to eight species of potential interest for turfs:Poa pratensis, Poa trivialis,Festuca rubra, Festuca arundinacea,Lolium perenne, Agrostis stolonifera,Agrostis tenuis, and Cynodon dactylon,this last being a warm-season grass. Poa pratensis andCynodon dactylon were mostly collected in northern Italyand Sardinia, respectively, whereas Festuca arundinacea andLolium perenne were rather ubiquitous. The collection sitesranged from 0 to 1040 m asl, but sites over 750 m wereonly visited in the inner part of Sardinia. All the accessions, collected aswhole plants, were transplanted at Lodi, northern Italy, where they are beingevaluated. Their preliminary evaluation for traits of importance for turf use,such as sward colour and overall quality, highlighted the great variation andthe occurrence of interesting accessions in all species. Other characters wererecorded, bearing specific importance in individual species, and in all casespromising accessions were identified. The germplasm of Festucarubra, Festuca arundinacea, and Loliumperenne proved highly infected by endophytic (symbiotic) fungi of thegenus Neotyphodium.     

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.     

Leaf position and genotype differences for mineral element concentrations in sorghum grown on tropical acid soil 1

Mineral element deficiencies and toxicities are common problems associated with sorghum [Sorghum bicolor (L.) Moench] production on acid soils. To better understand some of the mineral element problems and the analysis of plant tissue of sorghum plants grown on acid soils, four sorghum genotypes were grown on an acid Oxisol at Carimagua, Colombia limed with dolomite at 2 and 6 Mg ha^‐1.

Samples for mineral element analyses were obtained from leaves at different positions on the four genotypes. Concentrations of P and Mg were highest in the flag leaf (Leaf No. 1) and decreased as the position on the plant declined from the top of the plant for plants grown at 2 Mg lime ha^‐1. Similar decreases in P, Mg, K, and Zn concentrations occurred in plants grown with 6 Mg lime ha^‐1. Concentrations of Ca, S, Si, Mn, Fe, Cu, and Al increased as leaf position declined from the flag leaf for plants grown at 2 and 6 Mg lime ha^‐1. The higher lime supply enhanced Ca and reduced Mn and Fe concentrations in leaves. Differences in mineral element concentrations for the four genotypes used were fairly extensive. The elements to show the greatest range among genotypes were Al and Si and the elements to show the least range among genotypes were P, K, and S. Care should be used in collecting leaf samples for plant analysis and genotypic differences for accumulation of mineral elements should be considered in interpretation of results.