新疆下坂地水利枢纽工程帷幕灌浆室内试验分析

采用现场取得的地层材料，模拟实地的地层结构，通过帷幕灌浆的室内模拟试验，取得垂直防渗试验帷幕灌浆的压力、流量、渗透系数等参数，以对下坂地水库坝基深厚覆盖层现场帷幕灌浆成果做进一步对比分析。     

The biological deep sea hydrothermal vent as a model to study carbon dioxide capturing enzymes

Deep sea hydrothermal vents are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis) a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO₂ from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO₂ fixation and assimilation might be very useful. This review describes some current research concerning CO₂ fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture.     

创伤致实验动物深静脉血栓形成的研究

为观察创伤致实验动物深静脉血栓形成及其组织学变化,分别选用犬、新西兰兔及Wistar大鼠作为实验动物,进行骨科有创手术过程,其中犬24条进行人为股骨颈骨折钢板内固定手术,新西兰兔20只行单侧肢股骨骨折后髋人字石膏固定术,Wistar大鼠30只行单侧肢体（左后肢）骨缺损性骨折后髋人字石膏固定术。以大体解剖,血管彩超,血管组织学,血常规等指标进行检测深静脉血栓的形成。结果受试犬中有10条犬在术后4周内陆续死亡,尸检可见心脏内形成鸡脂样血栓,另有4条犬在术后6周及8周死亡,尸检心脏内见到血栓,其余犬饲养至48周,未见血栓形成,总体血栓形成率为58．3％;新西兰兔手术后饲养至8周,患肢每周进行血管彩超检测,未检测到血栓形成,但术部有大量囊性积液;30只大鼠术后9d内镜检肢体深静脉血栓形成率为77．8％。本试验表明骨科有创手术可致实验动物深静脉血栓形成,不同种属间有差异,犬及大鼠的发生率比兔要高,在用实验动物进行骨科的相关研究课题及临床兽医进行手术时要采取必要的预防措施。     

Fisher discriminant analysis model for selecting the retaining structure type of deep foundation pit

Aiming at the problem of traditional evaluation methods of deep foundation pit for selecting the retaining structure type, based on the statistical theory and following the principle of security, economic and reasonable, a Fisher discriminant analysis(FDA) model for selecting the retaining structure type for deep foundation pit is established. 10 selected indicators which influence selection of deep excavation program are taken into account as discriminant factors, and the supporting schemes for deep foundation pit are classified into 5 groups, viz. gravity of the cement-soil type, soil nailing wall, pile anchors, pile supports and underground continuous wall. After training and testing 64 sets of measured data, the discriminant functions of FDA are solved, the re-substitution method is introduced to verify the stability of FDA model and the ratio of mis-discrimination is 14.1%. Another 10 groups of measured data are tested as forecast samples by the proposed model, and the correct rate is equal to 100%. Therefore, the feasibility of the proposed model is validated. Moreover, the proposed model is adopted for the New World Center Project in China, and the prediction results are in line with the artificial neural network(ANN) and the actual situation. The result shows that the deep foundation pit supporting structure lectotype decision of FDA model has excellent discriminant performance and the resubstitution error rate is low. It is easy and efficient to make discriminant analysis using this model and it provides efficient method to select deep excavation retaining structure and a practical new approach to choose the structural type of deep foundation pit optimization.     

前历深水灌溉对水稻障碍型冷害的防御效果

本文在冷害年通过田间栽培和冷水处理的冷害模拟试验，自然条件下验证佐竹等人曾在人工气候室实验证实的前历深水灌溉对水稻孕穗期耐冷性变动的影响及其冷害防止的实际效果。结果表明，前历深水在无冷害的一般年，可增产３％～５％，而冷害年幼穗形成期开始１０ｃｍ深灌的前历深水比普通的５ｃｍ浅水增产１３％～２０％，而前历１０ｃｍ深水同危险期２０ｃｍ深水并用，就增产２０％～３０％．而且前历１０ｃｍ深水的效果，比危险期２０ｃｍ深水的效果还高。     

翻耕深度对遮阴油菜根系生长和养分吸收利用的影响

【目的】长江流域油菜季降雨丰沛,导致该地区光照强度下降,加之密植技术的推广,加剧了个体间对光照的竞争。故光照不足、土壤质地差成为制约该地区油菜高产的重要因素。通过研究耕作深度对遮阴油菜根系生长和养分利用的影响,以期为油菜的稳产增收提供理论支撑。【方法】2019—2021年在湖北武汉华中农业大学试验基地进行裂区试验,品种为主区（湘杂油518,XZY518;浙油50,ZY50）,土壤翻耕深度（T5,5 cm;T20,20 cm）为副区,不同光照强度（S0,0%遮阴;S1,30%遮阴）为副副区,研究不同耕作深度下遮阴油菜的土壤养分和理化性质、干物质累积、抗氧化酶活性、根冠生长、养分吸收的变化。【结果】深耕可以促进各层土壤的有机质、碱解氮、速效磷和速效钾养分的积累,其中10—20 cm土壤的养分含量增幅最大,为7.5%—42.3%。两种翻耕深度下,遮阴均导致土壤电导率下降,根表面积减少13.3%—36.6%,主根长、根冠比和侧根占比增加,氮素利用率显著下降3.0%—28.4%,根系干重减少,抗氧化酶（POD、SOD、CAT）活性增加。遮阴条件下,翻耕深度的增加,使土壤含水量降幅减小,油菜主根伸长且根表面积增大,根冠比和侧根占比增加,氮素利用率提高,根系的抗氧化酶（POD、SOD）活性增强,干物质积累增多。方差分析表明翻耕深度和遮阴对根系形态、干物质累积、抗氧化酶活、养分利用的互作效应多呈显著或极显著水平。在浅耕和深耕条件下,与正常光照相比,遮阴导致根表面积分别下降24.9%—36.6%、13.3%—19.2%,氮素利用率分别下降10.0%—28.4%、3.0%—23.9%。【结论】弱光胁迫下,深耕通过提高各层土壤养分含量,使油菜主根伸长,侧根占比增加,根表面积增大,同时根系抗氧化酶活力的增强延缓了根系的衰老,使根系养分吸收能力增强,氮素利用率增大,干物质积累量增大,最终促进了油菜的生长。     

连续旋耕下深耕对寒地优质粳稻产量形成的影响

【目的】 研究连续旋耕下深耕对不同优质粳稻生长动态、光合物质生产及产量形成过程的影响,为寒地优质粳稻高产高效栽培提供技术支撑。【方法】 2018—2019年以绥粳18、垦稻12和三江6为供试材料,在秸秆还田条件下,前茬连续2年旋耕基础上,设置深耕和旋耕2种耕作方式,研究耕作方式对优质粳稻生长动态及花后物质生产特性的影响。【结果】 年份间产量差异不显著,而耕作方式对寒地优质粳稻生长发育、花后光合物质生产特性及产量性状存在显著影响。与旋耕相比,深耕显著增加了每平方米分蘖数和有效穗数,剑叶展开时间晚且持续时间长,抽穗晚但持续时间无变化;增加了生物量和茎鞘干物质转运能力,其中齐穗期生物量和茎鞘干物质分别增加8.34%和5.36%;输出量、输出率及转化率增幅分别为13.19%、6.70%和9.17%,差异显著（P<0.05）;提高了齐穗期与成熟期叶面指数,延长了绿叶面积持续时间,增加了群体生长速率;促进了主茎倒3、4节位的节间长度、叶片长度和宽度,增加了株高和穗长;每穗粒数和粒重分别增加7.05%和3.37%,收获指数增加1.90%,实现产量平均增幅12.78%。同一耕作方式条件下,在茎蘖数、光合物质生产能力、茎鞘干物质积累量及转运能力、产量及其构成上均以垦稻12表现最佳,绥粳18次之;而三江6花后叶面积指数、成熟期每穗粒数和粒重虽然较高,但并不能弥补其干物质转运能力、有效穗数和千粒重低的不足。在互作效应上,深耕×垦稻12处理表现出较高的每平方米有效穗数,花后光合物质生产及转运能力强,粒叶比和群体生长速率高,千粒重与收获指数高,增产9.15%—27.47%。【结论】 在连续旋耕稻田上搭配一次深耕的耕作方式是利于提高本区域优质粳稻产量的耕作制度。     

Effects of deep vertical rotary tillage on the grain yield and resource use efficiency of winter wheat in the Huang-Huai-Hai Plain of China

Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study carried out in the Huang-Huai-Hai(HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties,winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels,and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain.A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1),2017–2018 (S2) and 2018–2019 (S3),with DVRT (conducted once in June 2016) and CT performed in the main plots.Subplots were treated with one of four targeted productivity level treatments (SH,the super high productivity level;HH,the high productivity and high efficiency productivity level;FP,the farmer productivity level;ISP,the inherent soil productivity level).The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years,which were due to the significant effects of DVRT.Compared with CT,grain yields,partial factor productivity of nitrogen (PFP_N),and water use efficiency (WUE) under DVRT were increased by 22.0,14.5 and 19.0%.Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes.General line model analysis revealed that tillage mode played a significant role on grain yield,PFP_N and WUE not only as a single factor,but also along with other factors(year and productivity level) in interaction manners.In addition,PFP_N and WUE were the highest in HH under DVRT in all three growth seasons.These results provided a theoretical basis and technical support for coordinating the high yield with high resource use efficiency of winter wheat in the resource-restricted region in the HHH Plain of China.     

Effects of mechanized deep placement of nitrogen fertilizer rate and type on rice yield and nitrogen use efficiency in Chuanxi Plain,China

This paper investigates the yield and nitrogen use efficiency (NUE) of machine-transplanted rice cultivated using mechanized deep placement of N fertilizer in the rice–wheat rotation region of Chuanxi Plain, China. It provides theoretical support for N-saving and improves quality and production efficiency of machine-transplanted rice. Using a single-factor complete randomized block design in field experiments in 2018 and 2019, seven N-fertilization treatments were applied, with the fertilizer being surface broadcast and/or mechanically placed beside the seedlings at (5.5±0.5) cm soil depth when transplanting. The treatments were: N0, no N fertilizer; U1, 180 kg N ha^–1 as urea, surface broadcast manually before transplanting; U2, 108 kg N ha^–1 as urea, surface broadcast manually before transplanting, and 72 kg N ha^–1 as urea surface broadcast manually on the 10th d after transplanting, which is not only the local common fertilization method, but also the reference treatment; UD, 180 kg N ha^–1 as urea, mechanically deep-placed when transplanting; M1, 81.6 kg N ha^–1 as urea and 38.4 kg N ha^–1 as controlled-release urea (CRU), mechanically deep-placed when transplanting; M2, 102 kg N ha^–1 as urea and 48 kg N ha^–1 as CRU, mechanically deep-placed when transplanting; M3, 122.4 kg N ha^–1 as urea and 57.6 kg N ha^–1 as CRU, mechanically deep-placed when transplanting. The effects of the N fertilizer treatments on rice yield and NUE were consistent in the 2 yr. With a N application rate of 180 kg ha^–1, compared with U2, the N recovery efficiency (NRE), N agronomic use efficiency (NAE) and yield under the UD treatment were 20.6, 3.5 and 1.1% higher in 2018, and 4.6, 1.7 and 1.2% higher in 2019, respectively. Compared with urea alone (U1, U2 or UD), the NRE, NAE and yield achieved by M3 (combined application of urea and controlled-release urea) were higher by 9.2–73.3%, 18.6–61.5% and 6.5–16.5% (2018), and 22.2–65.2%, 25.6–75.0% and 5.9–13.9% (2019), respectively. Compared with M3, the lower-N treatments M1 and M2 significantly increased NRE by 4.0–7.8% in 2018 and 3.1–4.3% in 2019, respectively. Compared with urea surface application (U1 or U2), the yield under the M2 treatment was higher by 4.3–12.9% in 2018 and 3.6–10.1% in 2019, respectively. Compared with U2, the NRE and NAE under the M2 treatment was higher by 36.9 and 36.3% in 2018, and 33.2 and 37.4% in 2019, mainly because of higher N uptake. There was no significant difference in the concentration of nitrate in the top 0–20 cm soil under U1, U2 and M2 treatments during the full heading and maturity stages. During the full heading stage, U2 produced the highest concentration of nitrite in 0–20 cm and 20–40 cm soil among the N fertilizer treatments. In conclusion, mechanized deep placement of mixed urea and controlled-release urea (M2) at transplanting is a highly-efficient cultivation technology that enables increased yield of machine-transplanted rice and improved NUE, while reducing the amount of N-fertilization applied.     

Assembly and co-occurrence patterns of rare and abundant bacterial sub-communities in rice rhizosphere soil under short-term nitrogen deep placement

Nitrogen (N) deep placement has been found to reduce N leaching and increase N use efficiency in paddy fields. However, relatively little is known how bacterial consortia, especially abundant and rare taxa, respond to N deep placement, which is critical for understanding the biodiversity and function of agricultural ecosystem. In this study, Illumina sequencing and ecological models were conducted to examine the diversity patterns and underlying assembly mechanisms of abundant and rare taxa in rice rhizosphere soil under different N fertilization regimes at four rice growth stages in paddy fields. The results showed that abundant and rare bacteria had distinct distribution patterns in rhizosphere samples. Abundant bacteria showed ubiquitous distribution; while rare taxa exhibited uneven distribution across all samples. Stochastic processes dominated community assembly of both abundant and rare bacteria, with dispersal limitation playing a more vital role in abundant bacteria, and undominated processes playing a more important role in rare bacteria. The N deep placement was associated with a greater influence of dispersal limitation than the broadcast N fertilizer (BN) and no N fertilizer (NN) treatments in abundant and rare taxa of rhizosphere soil; while greater contributions from homogenizing dispersal were observed for BN and NN in rare taxa. Network analysis indicated that abundant taxa with closer relationships were usually more likely to occupy the central position of the network than rare taxa. Nevertheless, most of the keystone species were rare taxa and might have played essential roles in maintaining the network stability. Overall, these findings highlighted that the ecological mechanisms and co-occurrence patterns of abundant and rare bacteria in rhizosphere soil under N deep placement.