农用地评估有关问题探讨

通过较系统地分析论述农用地的概念及特点，农用地的价格特性，归纳了其评估方法包括收益还原法，市场比较法，成本逼近法，剩余法，并指出各种方法的应用范围。     

课堂教学规范与评价探析

课堂教学是重要的教学组织形式。课堂教学规范，实际上是对课堂教学的一种基本要求。科学地规范课堂教学，建立科学的评价体系，是提高教学质量和教学水平的重要措施。     

The concept of probability in safety assessments of technological systems

Safety assessments of technological systems, such as nuclear power plants, chemical process facilities, and hazardous waste repositories, require the investigation of the occurrence and consequences of rare events. The subjectivistic (Bayesian) theory of probability is the appropriate framework within which expert opinions, which are essential to the quantification process, can be combined with experimental results and statistical observations to produce quantitative measures of the risks from these systems. A distinction is made between uncertainties in physical models and state-of-knowledge uncertainties about the parameters and assumptions of these models. The proper role of past and future relative frequencies and several issues associated with elicitation and use of expert opinions are discussed.     

Multi-mycotoxin exposure and risk assessments for Chinese consumption of nuts and dried fruits

In this study, 15 mycotoxins were detected in 233 nut and dried fruit samples from China. The 15 mycotoxins included aflatoxins(AFs: AFB_1, AFB_2, AFG_1 and AFG_2), trichothecene toxins(TCs: T-2, ZEA, ENA, ENA_1, ENB, ENB_1 and BEA), Alternaria toxins(ATs: TEN, AOH and AME) and ochratoxin A(OTA). The mycotoxins were detected in 47.6% of the samples and all 15 of the mycotoxins were found. Two samples were positive for AFB_1 and exceeded the maximum tolerable levels allowed in China. The contamination levels of the mycotoxins found in nuts, dried jujubes, raisins, dried figs and dried longans were in the ranges of 0.1–462.7, 0.2–247.3, 0.8–10.1, 0.2–384.1 and 0.1–89.2 μg kg–1, respectively. Dried figs(80.0%) had the highest incidence of mycotoxins, followed by dried longans(60.0%), dried jujubes(57.1%), nuts(43.6%) and raisins(26.7%). The estimated daily intake(EDI) values of each individual mycotoxin and all of the mycotoxins collectively were calculated by both the deterministic approach(DA) and the probability approach(PA). For risk characterization, dietary exposure to TCs, ATs and OTA through consumption of nuts and dried fruits according to both approaches, showed no health risk to Chinese adults by exposure to either individual mycotoxins or in combination. To the best of our knowledge, this is the first work in which risk assessment of multimycotoxins is performed, specifically including the emerging ENNs and BEA, in nuts and dried fruits of China.     

应用RAPD技术分析大蒜种质遗传特性和检测蒜种纯度的研究

报道了用RAPD技术鉴定大蒜种质遗传特性和蒜种纯度的研究结果。从 10 5个随机引物 (OperonNo 1～ 5 ,OPE1～ 2 0 ,OPF1～ 2 0 ,OPG1～ 2 0 ,OPH1～ 2 0 ,OPI1～ 2 0 )中筛选出 12个有鉴别作用的引物。用筛选出的引物与 80份来自澳大利亚、泰国和我国 17个省、市的大蒜种质进行RAPD测定。确立了大蒜PCR反应体系、条件和程序 ,制定了凝胶电泳操作规程。所得RAPD带谱具有良好的多态性和特异性。大蒜种质的RAPD带谱差异与其农艺学性状差异吻合。根据RAPD带谱分析了大蒜种质的遗传特性和亲疏关系 ,研究区分了同物异名、同名异物的大蒜种质 ,进行了蒜种纯度鉴定试验。试验证明 ,RAPD技术是鉴定大蒜种质遗传特性和蒜种纯度的有效技术之一     

遥感与地理信息系统技术在叙利亚沿海地区土壤侵蚀评价中的应用研究

在过去的几十年里,遥感与地理信息系统融合技术应用于土壤侵蚀评价的研究得到了显著的发展。本研究采用遥感资料、土壤和土地调查数据、数字地面模型和气象观测数据,利用地理信息系统技术来分别产生通用土壤流失方程（USLE）的各个参数,从而来评价水土流失量和空间分布状况。     

上海世博园区水体底泥重金属污染特征与评价

分析上海世博园区水体底泥中Hg、Cu、Zn、Cd、Pb、Cr、As、Se等重金属（类金属）含量,结果表明,№为（0．35±0．17）mg／kg,Cu为（65．86±11．33）mg／kg,Zn为（190．9±28．9）mg／kg,Cd为（0．3585±0．0611）mg／kg,Pb为（32．50±11．04）mg／kg,Cr为（180．7±68．5）mg／kg,As为（10．8±5．5）mg／kg,Se〈0．02mg／kg。运用地累积指数I。。进行评价,结果表明cr和Zn有轻度污染。同时运用潜在生态危害指数RI进行评价,结果为中等生态风险,其中Hg为强生态风险。上海世博园区水体底泥受到Hg、cr、zn等重金属污染,应引起高度重视。     

富勒烯对大型蚤的急性毒性和慢性毒性效应

为深入理解富勒烯(Fullerene,nC_(60))的水生生态毒理效应,以模式动物大型蚤(Daphnia magna)为研究对象,研究nC_(60)对大型蚤的48 h和72 h急性毒性效应以及21 d慢性毒性效应。结果表明,急性暴露下,nC_(60)对大型蚤的48 h半抑制浓度(EC_(50))和半致死浓度(LC_(50))分别为25.3 mg·L~(-1)和28.5 mg·L~(-1),72 h的EC_(50)和LC_(50)分别为14.9 mg·L~(-1)和16.3 mg·L~(-1),且大型蚤的跳跃频率和心跳频率随着在nC_(60)中暴露时间的延长先增加后减少;慢性暴露下,1 mg·L~(-1)的nC_(60)即可对大型蚤的繁殖产生影响,21 d内总产蚤数和平均产蚤数分别为53.3个和0.3个,与对照相比明显降低。研究结果表明,无论急性还是慢性暴露下,nC_(60)均显著抑制大型蚤的生长和繁殖,其水生生态毒性不容忽视。     

金针菇菌糠营养价值评定及其对肉牛生产性能的影响

为研究金针菇菌糠的饲用价值,对金针菇菌糠和常规粗饲料进行营养组分分析,并设计6种菌糠与常规粗饲料的组合,通过人工瘤胃法测定每组单独饲喂以及与精料混合后的pH、NH_3-N浓度和干物质降解率,筛选出最佳组合方式。选择16头健康状况良好、年龄、体重相近的西门塔尔杂交公牛,随机分为对照组和试验组,每组8头牛。对照组饲喂普通全混合日粮(total mixed rations,TMR),试验组饲喂最佳组合方式的TMR日粮。预试期10 d,正试期80 d,试验初始和结束时进行称重和采血。测定最佳组合方式对肉牛日增重、血液生理指标和血浆生化指标的影响。结果显示:菌糠的营养组分接近稻草和黄贮,其最佳饲喂组合为青贮(50%)+菌糠(30%)+酒糟(10%)+豆腐渣(10%),该组合的饲喂极显著提高了肉牛日增重(P0.01),降低了饲料成本,并且不会对血液生理指标和血浆生化指标造成不良影响。以上结果表明,金针菇菌糠可以作为粗饲料在肉牛养殖中使用。     

上海世博园区水体底泥重金属污染特征与评价

分析上海世博园区水体底泥中Hg、Cu、Zn、Cd、Pb、Cr、As、Se等重金属（类金属）含量,结果表明,№为（0．35±0．17）mg／kg,Cu为（65．86±11．33）mg／kg,Zn为（190．9±28．9）mg／kg,Cd为（0．3585±0．0611）mg／kg,Pb为（32．50±11．04）mg／kg,Cr为（180．7±68．5）mg／kg,As为（10．8±5．5）mg／kg,Se〈0．02mg／kg。运用地累积指数I。。进行评价,结果表明cr和Zn有轻度污染。同时运用潜在生态危害指数RI进行评价,结果为中等生态风险,其中Hg为强生态风险。上海世博园区水体底泥受到Hg、cr、zn等重金属污染,应引起高度重视。     

粤西地区不同林分类型土壤重金属含量及生态风险评价

【目的】了解粤西地区不同林分类型土壤重金属的含量特征及污染情况,为其生态风险评价提供理论依据。【方法】以粤西地区桉树Eucalyptus urophylla人工林、马尾松Pinus massoniana人工林、杉木Cunninghamia lanceolata人工林、相思Acacia spp.人工林和阔叶混交林5种林分类型为研究对象,分析不同林分0~20 cm土层土壤中Cu、Zn、Pb、Cd和Ni的含量,并采用单项污染指数(Pi)法、内梅罗综合污染指数(PN)法和Hakanson潜在生态风险指数(RI)法对各林分土壤重金属污染情况进行污染评价及潜在生态风险评价。【结果】各林分土壤重金属含量均以Zn最高,Cd最低,但均未超过广东省土壤背景值;土壤pH为3.62~6.42,呈酸性。马尾松人工林土壤中Cu质量分数(16.06 mg·kg~(-1))及桉树人工林土壤中Pb质量分数(12.37 mg·kg~(-1))均显著高于阔叶混交林土壤中相应重金属的质量分数(9.21和6.87 mg·kg~(-1));人工林土壤重金属含量间的相关性显著。5种林分土壤重金属Pi均小于1,污染等级均为清洁;土壤重金属P_i及P_N均表现为:马尾松人工林杉木人工林桉树人工林相思人工林阔叶混交林,除马尾松人工林外,其余林分的综合污染等级均为安全。单一及多种重金属的潜在生态风险评价结果均为轻微风险,单一重金属潜在生态风险系数(E_i)表现为Cd最大,Zn最小,多种重金属RI表现为马尾松人工林最高,阔叶混交林最低。【结论】Hakanson潜在生态风险指数法能更综合地反映土壤受重金属污染情况;本研究评价结果表明,防止和减少森林土壤中人为的重金属输入仍是一项需要长久坚持的必要举措。     

小城镇发展状态模糊数学综合评价研究--以河北省鹿泉市铜冶镇为例

应用层次分析法，综合理论分析法和专家咨询法，建立了小城镇发展状态评价体系；建立了小城镇发展状态评价的递阶多级模糊数学模型，以河北省鹿泉市铜冶镇为例，通过选取适宜的模糊数学综合评判计算模型。应用评价体系和数学模型，对铜冶镇今后10年发展状态进行了定量评价，结果表明，铜冶镇(1998—2010年)发展状态为较好。     

沈抚灌区农田土壤重金属污染时空变化特征及生态健康风险评价

以东北典型污灌区——沈抚灌区农田土壤为研究对象,在收集整理沈抚灌区自20世纪末停灌后不同时期土壤重金属污染情况的相关文献报道后,沿灌渠主干以行政村为单位布设取样点28个,利用原子吸收分光光度法、数理统计法、空间插值法等研究了重金属元素Cd、Pb、Cu、Zn在灌区农田土壤和农作物中的污染现状及时空分布特征,并利用内梅罗污染指数法、EPA人体暴露风险评价法及潜在生态危害指数法对污灌区重金属污染土壤及农产品的潜在健康风险进行评价。结果表明:灌区土壤重金属的平均浓度为:Cd 0.60 mg·kg~(-1)、Pb 38.76 mg·kg~(-1)、Cu 22.39 mg·kg~(-1)、Zn 57.64 mg·kg~(-1),其中Cd含量超过了国家土壤环境质量二级标准;与文献报道该灌区近15年来土壤重金属污染情况相比,土壤中Cu、Zn含量明显降低,而Cd、Pb含量并无显著变化;土壤中4种重金属元素的空间分布特征各异,灌区土壤重金属综合污染水平属于轻微污染;Cd、Pb在玉米中残留浓度超过国家食品安全限值,对人摄食途径存在健康风险,尤其是Cd具有较强的潜在生态危害性。     

Mapping the fallowed area of paddy fields on Sanjiang Plain of Northeast China to assist water security assessments

Rice growth requires a large amount of water, and planting rice will increase the contradiction between supply and demand of water resources. Paddy field fallowing is important for the sustainable development of an agricultural region, but it remains a great challenge to accurately and quickly monitor the extent and area of fallowed paddy fields. Paddy fields have unique physical features associated with paddy rice during the flooding and transplanting phases. By comparing the differences in phenology before and after paddy field fallowing, we proposed a phenology-based fallowed paddy field mapping algorithm. We used the Google Earth Engine(GEE) cloud computing platform and Landsat 8 images to extract the fallowed paddy field area on Sanjiang Plain of China in 2018. The results indicated that the Landsat8, GEE, and phenology-based fallowed paddy field mapping algorithm can effectively support the mapping of fallowed paddy fields on Sanjiang Plain of China. Based on remote sensing monitoring, the total fallowed paddy field area of Sanjiang Plain is 91 543 ha. The resultant fallowed paddy field map is of high accuracy, with a producer(user) accuracy of 83%(81%), based on validation using ground-truth samples. The Landsat-based map also exhibits high consistency with the agricultural statistical data. We estimated that paddy field fallowing reduced irrigation water by 384–521 million cubic meters on Sanjiang Plain in 2018. The research results can support subsidization grants for fallowed paddy fields, the evaluation of fallowed paddy field effects and improvement in subsequent fallowed paddy field policy in the future.