典型煤矿工业园区土壤重金属污染评价

随着工业化进程的加快,一些农业用地转为工业用地,土地用途的转变可能会影响周围土壤的质量。该研究以河南省东部某煤矿工业园区为对象,分成不同小区采集土壤样品,分析工业园区内表层土壤的Hg、Cd、Zn、As、Pb、Cr六种重金属含量及污染评价,并同时与周边土壤重金属含量进行比较,分析可能造成土壤环境污染的因子。结果表明,根据土壤环境质量标准,工业园区域内土壤污染指数小于0.7,土壤清洁;但与周边土壤比较存在污染的风险,潜在重金属威胁主要表现为Hg,其他重金属污染风险趋势为Cd>Zn>As>Pb>Cr;在空间分布上,除Cr外,随着与工业园区距离的加大,其他五种重金属其含量有降低的趋势;同时根据结果提出合理土壤污染防控建议。     

低温胁迫下暖季型草坪草质膜透性比较研究

以狗牙根、中华结缕草、假俭草、百喜草4个草种为试验材料,用电导率测定其分别在5℃、0℃、-5℃、-10℃不同低温下12h、24h、36h、48h的电解质外渗率的变化,并对4个草种抗寒过程进行方差分析。结果表明,低温处理后各草种叶片电解质的外渗率呈S型曲线增加。中华结缕草电解质透出率变化缓慢,具有较强的抗寒性。假俭草抗寒性最弱。4种试材抗寒强弱顺序为:中华结缕草>狗牙根>百喜草>假俭草。     

玉米弯孢叶斑病菌NADPH氧化酶生物信息学分析和ATMT敲除载体的构建

从JGI数据库玉米弯孢叶斑病菌(Curvularia lunata)基因组中获得2个编码NADPH氧化酶基因ClNox1和ClNox2。采用生物信息学方法对2个基因编码的蛋白质进行性质、结构和功能等方面的预测。结果表明,ClNox1和ClNox2的分子量分别为6.35和6.41 KD,等电点PI为8.87和8.93,不稳定指数为44.50和39.45;ClNox1是亲水性膜蛋白,包含6个明显的跨膜结构域;ClNox2也是膜蛋白,包含8个明显的跨膜结构域。在亚细胞水平上,ClNox1定位于线粒体上,而ClNox2定位于细胞质膜上;在氨基酸序列方面,ClNox1和ClNox2都含有多个苏氨酸、丝氨酸和酪氨酸激酶磷酸化位点;在功能方面,ClNox1和ClNox2都包含NADPH氧化酶特征结构域,并且与Cochliobolus heterostrophus的NADPH氧化酶基因具有较高的同源性。根据ClNox1和ClNox2序列设计特异性引物扩增目的片段,与标记基因NPTII和HphGFP分别连入骨架载体pPZP100,构建完成ClNox1和ClNox2基因的敲除载体pPZP100NPTIIClNox1和pPZP100HphGFPClNox2,为根癌农杆菌介导的遗传转化提供基础材料。     

槐豆木虱若虫空间分布型及抽样技术研究

应用6种分布型指数法分析判定了槐豆木虱[Cyamophila willieti(Wu)]若虫在国槐(Sophora japonicaLinnaeus)上的空间分布型,利用Taylor(1961)幂法则和Iwao(1971)回归方程分析聚集原因,结果表明,槐豆木虱若虫在国槐上呈聚集分布,公共kc值为5.159 0,且符合负二项分布;其种群聚集原因是由昆虫本身行为习性所致。在此基础上,采用Iwao的方法确定了槐豆木虱若虫的田间理论抽样数和序贯抽样表。     

Effects of long-term treatments of different organic fertilizers complemented with chemical N fertilizer on the chemical and biological properties of soils

Continuous cultivation has been known to decrease soil organic matter content. Application of organic matter to cultivated soil is an important practice from the point of view of maintaining an adequate amount of soil organic matter. Soil organic matter content significantly affects soil microbial activity, which is an important index of soil quality. In this study, a field experiment was conducted to examine the long-term effects of different kinds of organic matter in combination with inorganic nitrogen (N) fertilizer on chemical and biological properties of soils. There were seven treatments, namely (1) CK (without fertilization), (2) Chem-N (applying chemical N fertilizer only), (3) Comp (applying compost with the same rate of N as the Chem-N treatment), (4) Comp + l/3 N (applying compost complemented with 33% of the chemical N fertilizer of the Chem-N treatment), (5) Comp + 2/3 N (applying compost complemented with 66% of the chemical N fertilizer of the Chem-N treatment), (6) GM + 1/3 N (applying green manure complemented with 33% of the chemical N fertilizer of the Chem-N treatment) and (7) Peat + 1/3 N (applying peat complemented with 33% of the chemical N fertilizer of the Chem-N treatment). After continuous treatment for 12 years and with cultivation of 24 crops on the same area, soils were sampled for analyses of chemical and biological properties, enzymatic activities and phospholipid fatty acid (PLFA) profiles. The results showed that compared with CK and Chem-N treatments, applications of compost and peat increased soil organic carbon (SOC) content and altered microbial activities and microbial community structure. However, application of green manure for 12 years had no effect on SOC content. Both microbial activities and PLFA profiles were clearly dependent on the characteristics of the applied organic amendments. In summary, a peat application led to the highest increase in SOC content compared to compost and green manure; however, compost-treated soil had a higher microbial population and higher microbial and enzyme activities, while the effects of both green manure and chemical N fertilizer on soil properties were similar.     

Efficacy of different dosages of ivermectin injectable against the Hypoderma spp. in yaks

A chemotherapy trial was conducted to determine the lowest dosage of injectable preparation of ivermectin against Hypoderma spp. infestation in yaks in Tibetan areas in Tianzhu county, Gansu province, in northwest of China. One hundred and sixty yaks were randomly divided into four groups of 40 yaks for the trial. The first three groups were treated by subcutaneous injection in the neck with 0.1% ivermectin (respectively, 1, 5, 10 microg/kg body weight). The fourth group was not treated and considered as control group. All the experiments were performed in November 2000 and the animals were examined for the presence of warbles in the next March and May. The results indicated that there was no warbles found on the back of treated animal while third stage larvae were palpated on back of some of the yaks in control group. It is concluded that dosage of 1 microg/kg ivermectin injectable was sufficient to kill or stop development of larvae of Hypoderma spp. in naturally infected yaks if administrated in November.     

蒙古蒿挥发油对三种主要枸杞害虫的控制作用

为保障枸杞产品质量安全,采果期不受化学农药干预,本研究通过室内毒力测定和田间药效试验评价了蒙古蒿挥发油的杀虫活性。结果表明,蒙古蒿挥发油对棉蚜的LC₅₀为7.82mg/mL;对枸杞木虱的LD₅₀为2.89μg/头;对西花蓟马的LC₅₀为2.80mg/mL,均低于对照药剂印楝素提取物,其中胡椒酮、PPG2-甲醚和桉油烯醇起主要杀虫作用。利用响应面分析,蒙古蒿挥发油制备成8.5%蒙古蒿挥发油微胶囊剂,该制剂在质量浓度6kg/hm²条件下,药后1d,对枸杞蚜虫、西花蓟马和枸杞木虱的防效分别为75.95%、58.81%和32.14%,高于对照0.3%印楝素乳油,杀虫效果一直持续到21d。本研究将蒙古蒿挥发油微胶囊应用于枸杞园采果期防治主要害虫,持效期长,具有进一步开发成高效植物源农药的潜力。     

丹江口库区土壤侵蚀对土地利用变化的响应

[目的]探讨土壤侵蚀对土地利用变化的响应,为库区土壤侵蚀的防治提供借鉴性意见,从而为制定保障丹江口水质安全的措施提供科学支持。[方法]利用遥感影像解译的土地利用类型(2002—2013年),分析丹江口库区土地利用变化,同时利用修正的土壤流失模型RUSLE对土壤侵蚀量进行模拟分析,探讨土壤侵蚀对土地利用变化的响应。[结果]丹江口库区在2002—2013年期间主要的土地利用变化集中在林地、耕地、灌草地之间的转移以及建设用地的扩张,具体表现为林地面积扩大了13.72%,耕地面积小幅增加了5.76%,而灌草地面积大幅减少了37.61%,建设用地增长了2.40倍。丹江口库区2002,2008,2013年均以微度侵蚀占主导。库区土壤的整体侵蚀强度减轻,但土壤侵蚀在城市扩张地区增加明显。[结论]丹江口库区的土地利用变化及土壤侵蚀强度的改变主要受退耕还林、天然林保护等政策措施和城市扩张的影响。库区的土壤侵蚀程度在总体上具有降低的趋势,但在城镇化区域,土壤侵蚀状况急剧恶化。     

我国农村生活污水治理的现状分析和对策探究

随着我国“乡村振兴”“厕所革命”等国家战略的实施,我国农村生活污水的治理也越来越受到重视,但是农村生活污水不同于城市生活污水,它的治理在标准、模式、技术、运维等方面存在诸多问题。本文详细介绍了我国农村污水治理现状,针对全国不同地区农村生活污水处理工艺和典型案例,从处理技术、排放标准以及运维管理等方面进行了系统分析,重点论述了处理技术的优缺点,并结合农村自然的自净能力和面源污染的根本原因,提出了建立排放标准的合理前提,同时也介绍了智慧运维在农村生活污水处理中的积极作用。另外,根据农村居住分散、地势差异大的特点,强调了分散式处理的重要性,旨在从根本上解决农村生活污水收集难、处理复杂的难题,以生态处理模式实现美丽乡村建设。     

秸秆还田对长期不同施肥黑土微生物残体碳的影响

  【目的】  研究长期施肥以及秸秆还田对黑土中微生物标识物氨基糖含量的影响,以期为调节黑土碳循环提供理论支撑。  【方法】  吉林省农业科学院黑土长期定位试验始于1990年,2018年选取其中不施肥对照(CK)、单施化肥(NPK)和有机肥配施化肥(MNPK) 三个处理进行秸秆微区田间试验。这三个处理的土壤中分别再设加入1 cm 长玉米秸秆6000 kg/hm2的处理(CKS、NPKS、MNPKS)和不加入玉米秸秆的处理(CK、NPK、MNPK),共6个处理。秸秆与土壤混匀后置于PVC框(长0.9 m、宽0.6 m、高0.6 m)内,PVC框上端高于地面20 cm。在PVC框埋入土壤60天(夏季)、150天(秋季)后,取土样测定理化性状及氨基葡萄糖(GluN)、氨基半乳糖(GalN)和胞壁酸(MurN)含量。微生物真菌残体碳和细菌残体碳含量依据各氨基糖含量计算。  【结果】  与CK相比,NPK和MNPK处理能够促进氨基糖在土壤中的积累,其中第60天氨基葡萄糖分别显著增加18.81%和105.36%;胞壁酸分别显著增加19.62%和129.30%。两种施肥措施均能提升土壤中微生物残体碳的含量,而且MNPK处理微生物残体碳积累量较CK处理高出近1倍。各处理中真菌残体碳含量要远高于细菌残体碳含量,两种施肥措施均会降低真菌残体碳占微生物残体碳的比重,说明施肥会增加细菌在这一过程中对黑土有机碳积累的贡献。NPKS处理氨基葡萄糖占总氨基糖含量百分比明显增加,MNPKS处理真菌来源的氨基葡萄糖所占百分比也在第60天、第150天这两个时期内逐渐上升,表明真菌细胞死亡残体积累量在增加。  【结论】  添加秸秆后的MNPK处理促进了黑土中微生物残体碳的积累,NPK处理与秸秆添加相结合可以提高真菌残体碳在微生物残体碳中所占比重。因此,施肥和秸秆添加会使黑土中微生物群落组成发生变化,从而影响微生物残体的积累特征。