基于3S技术和AHP的贵阳市土地综合承载力研究

近年来，随着中国经济的快速发展，人地关系变得越来越紧张。主要讨论了贵阳市研究区的土地综合承载力状况，利用GIS和RS技术对研究区土地利用现状和地形地貌特点进行深入分析，建立“空间属性一体化”数据库。构建了一套适合区域土地承载力综合评价指标体系，并运用层次分析法确定各个指标权重，求算出贵阳市各个地区土地承载力综合评价分值，最后将贵阳市的土地承载力划分为3个类型区：一是低承载力区（Y〈0．2），有花溪区、清镇市、修文县、息烽县、开阳县；二是中等承载力区（0．2〈Y〈0．5）。属于这种类型区的有4个地区，主要包括乌当区、白云区；三是高承载力区（Y〉0．5），主要有南明区、云岩区和小河区。这3个类型区分别代表土地承载力演替从低层次的均衡发展阶段到较高层次的不均衡发展阶段再到高层次的系统协调均衡发展阶段。结果表明，贵阳市目前的土地资源处于紧张状态，但不同的地区又有所差异，表现出一定的空间地域性，最后对当地土地利用政策制定，提出了建议。     

Studies on the origin of the methylsulfonyl‐containing metabolites from propachlor

Abstract

Metabolites in which the chlorine from propachlor has been replaced by a cysteine group or a methylsulfonyl group [‐S(O₂) CH₃] are present in the urine of rats dosed orally with propachlor. In the present study, urine from rats given single oral doses of ³⁵S‐labeled cysteine conjugate of propachlor contained metabolites having the methylsulfonyl groups labeled with S. No metabolites containing ¹⁴C‐labeled methylsulfonyl groups were isolated from urine of rats given single oral doses of the cysteine conjugate of propachlor in which the cysteine group was uniformly labeled with ¹⁴C. These findings show that the cysteine conjugate of propachlor is the source of sulfur in the methylsulfonyl‐containing metabolites. Therefore, we suggest that a C‐S lyase present in the animal cleaves the cysteine conjugate of propachlor and thus allows further metabolism of the sulfur to a methylsulfonyl moiety.     

Effects of DDT and piperonyl butoxide on the metabolic alterations in pigeon (columba livia)

Abstract

Effect of acute doses of technical grade of dichloro diphenyl trichloro ethane (DDT) and piperonyl butoxide (PB) on hepatic micro‐somal cytochrome P₄₅₀ (Cyt. P450) and cytosolic glutathione‐S‐transferase (GST) activity in pigeon were studied after 24 hours of treatment. A completely reverse trend of changes in Cyt. P450 and GST activity were found as increase in Cyt. ?450 paralleled with decrease in GST activity following exposure to DDT. However, intensity of changes in Cyt. P450 was greater than that of GST. A dose dependent decrease in Cyt. ?450 and GST activity was observed after PB treatment. The study may, therefore, throw some light on metabolic alterations in wild birds resulting from environmental pollution by DDT and allied chemicals.     

Effects of herbicide stress on wheat cultivars from organic and conventional cropping systems

Abstract

Wheat (Triticum aestivum L.) seedlings grown from seeds produced in “organic”; (non‐chemical) and “conventional”; cropping systems are characterized by a) similar rates of root and shoot growth, b) equal sensitivity to phytotoxicity by the herbicide glyphosate, and c) equivalent basal activity of the enzyme glutathione S‐transferase (both in the roots and in the shoots). In addition, treatment of these seedlings with glyphosate leads to significantly higher contents of this enzyme both in the shoots and in the roots. However, time‐course and dose‐response investigations indicate significant differences in the induction pattern of glutathione S‐transferase: the response of “conventional”; wheat seedlings takes place earlier and with higher efficiency, than that of the “organic”; ones.     

用"3S"技术和景观生态学方法探索新农村之路

针对中国新农村建设面临的5个重大理论实践问题,用“35”技术和景观生态学开展了中国典型省区——四川省新农村建设道路研究,从城市-农村-自然三大景观差异、演变、协调、互动等角度,提出了正确认识农村的新思维、科学划分农村的新方法和探索新农村健康发展的新途径。     

生物炭和有机肥对菜地土壤N2O排放及硝化、反硝化微生物功能基因丰度的影响

通过室内培养试验和实时荧光定量PCR技术,研究了田间施用生物炭和有机肥对菜地土壤氧化亚氮(N_2O)排放、氨单加氧酶(amo A)和亚硝酸盐还原酶(nir S、nir K)、氧化亚氮还原酶(nos Z)基因丰度的影响,并探讨功能基因丰度对N_2O排放的影响.试验设置5个处理:CK(对照)、N(尿素)、N+BC(尿素和生物炭)、N+M(尿素和有机肥)和N+BC+M(尿素、生物炭和有机肥).结果表明,与CK处理相比,各施肥处理均降低了土壤氨氧化细菌(AOB)和氨氧化古菌(AOA)丰度,增加了nir K、nir S和nos Z基因丰度,并提高了培养期间N_2O累积排放量.与N处理相比,N+BC处理的土壤p H值提高了11.1%,并增加了AOB、AOA、nir S、nir K和nos Z基因丰度,增幅分别为105.8%、57.3%、22.0%、176.2%和204.9%,同时显著降低了培养期间N_2O累积排放量,降幅为58.1%;N+M处理增加了nir K和nir S基因丰度,增幅分别为58.8%和7.1%,对N_2O排放的影响不显著;N+BC+M处理增加了AOB、nir K、nir S和nos Z基因丰度,增幅分别为30.7%、68.7%、6.5%和84.5%,降低了N_2O累积排放量,降幅为14.4%.生物炭通过增加amo A、nir S和nir K基因丰度间接增加N_2O排放,同时通过增加nos Z基因丰度促进N_2O还原,综合效应表现为降低了菜地土壤N_2O排放.因此,通过施用生物炭改善土壤性质,增加功能基因丰度,降低土壤N_2O排放,是一种较好的N_2O减排措施.施用有机肥可以增加反硝化作用功能基因丰度,但对N_2O减排效果不显著.     

喷消石灰脱除垃圾焚烧炉尾气中HC1和SO2的试验研究

在日处理200t进口流化床垃圾焚烧炉上，进行烟气喷水降温加上喷消石灰粉末胶除尾气中的酸性气体HC1和SO2的试验研究，HC1和SO2浓度由布袋除尘器出口的在线气体分析仪测得，结果表明HC1和SO2的去除率在Ca/C1摩尔比等于9时分别在80%和20%，说明该法消石灰利用率较低，宜改为半干法脱除HC1和SO2酸性气体以便降低吸收剂用量，提高运行的经济性。     

改性煤矸石对上覆水磷及底泥磷代谢关键基因的影响

将热活化煤矸石和镧改性煤矸石应用于封闭水体除磷固磷试验,采用16SrRNA高通量测序技术分析底泥微生态群落结构、聚磷细菌和磷代谢功能基因的变化.结果表明：镧改性煤矸石对上覆水TP的去除能力最高,稳定期上覆水TP浓度为0.023~0.028mg/L,较对照组低83.5%以上,热活化煤矸石对上覆水TP的去除能力较差,稳定期上覆水TP浓度为0.15mg/L左右,略低于对照组.热活化煤矸石和镧改性煤矸石均提高了底泥中微生物多样性,变形菌门（Proteobacteria）和绿弯菌门（Chloroflexi）为底泥优势菌种.不同处理组底泥中聚磷细菌为Tetrasphaera和Candidatus_Accumulibacter,镧改性煤矸石显著降低了底泥中聚磷细菌的相对丰度.热活化煤矸石和镧改性煤矸石对多聚磷酸盐激酶（PPK）影响不大,但对外切聚磷酸酶（PPX）的抑制较大,热活化煤矸石抑制最大.     

松花江表层沉积物中16种多环芳烃空间分布特征及生态风险评价

为揭示松花江干支流表层沉积物中16种PAHs（多环芳烃）的空间分布特征及其生态风险状况,采用气相色谱-质谱联用仪分析了2017年9月松花江干支流26个表层沉积物16种PAHs质量分数特征,并采用比值法对其污染来源进行解析,运用沉积物质量基准法和质量标准法评价其生态风险状况.结果表明:①松花江干支流表层沉积物中w（∑₁₆PAHs）为169.76~3 769.19 ng/g,以3~6环高环为主,并且支流w（∑₁₆PAHs）（范围为169.76~3 769.19 ng/g,平均值为1 598.41 ng/g）高于干流（范围为459.92~2 092.58 ng/g,平均值为1 173.67 ng/g）,呈从上游到下游逐渐降低的趋势.②松花江干支流表层沉积物中w（∑₁₆PAHs）主要来源于生物质燃烧和石油燃烧.③松花江干支流表层沉积物中w（∑₁₆PAHs）总体处于低生态风险水平,个别支流点位（3个）会发产生经常性生态风险.研究显示,松花江流域干支流表层沉积物中w（∑₁₆PAHs）呈从上游到下游逐渐降低的趋势,并且支流高于干流,但总体处于低生态风险水平.      

Inhibition effect of magnetic field on nitrous oxide emission from sequencing batch reactor treating domestic wastewater at low temperature

This study aims to investigate the effect of a magnetic field on nitrous oxide(N_2O) emission from a sequencing batch reactor treating low-strength domestic wastewater at low temperature(10℃).After running for 124 days in parallel,results indicated that the conversion rate of N_2O for a magnetic field-sequencing batch reactor(MF-SBR) decreased by34.3% compared to that of a conventional SBR(C-SBR).Meanwhile,the removal efficiencies for total nitrogen(TN) and ammonia nitrogen(NH4-N) of the MF-SBR were 22.4% and 39.5% higher than those of the C-SBR.High-throughput sequencing revealed that the abundances of AOB(Nitrosomonas),NOB(Nitrospira) and denitrifiers(Zoogloea),which could reduce N_2O to N_2,were promoted significantly in the MF-SBR.Enzyme activities(Nir) and gene abundances(nos Z nir S and nir K) for denitrification in the MF-SBR were also notably higher compared to C-SBR.Our study shows that application of a magnetic field is a useful approach for inhibiting the generation of N_2O and promoting the nitrogen removal efficiency by affecting the microbial characteristics of sludge in an SBR treating domestic wastewater at low temperature.