宁夏移民区种植业生态系统的能值分析——以红寺堡移民开发区为例

从能值的角度出发,以宁夏移民区代表区域红寺堡移民开发区2007年统计数据与调查数据为基础,对该区种植业生态系统的能值投入与产出进行首次分析.建立了由环境承载率、净能值产出率、能值投入率和可持续发展指数等构成的评价指标体系,并与同类地区和一些发达地区进行了对比分析,结果表明:该区种植业生态系统能值投入以不可更新的工业辅助能为主,尤其以化肥为主,能值投入率、净能值产出率相对较低,环境承载率较高,对环境的压力很大;可持续性发展指数很低,属于消费型经济系统.基于红寺堡移民开发区种植业系统能值分析的特点,提出了促进系统可持续发展的对策建议.     

黄土高原丘陵沟壑区典型县域的能值分析

以能值理论为基础,以黄土高原丘陵沟壑区典型县安塞为例,通过一系列的能值指标定量分析了该县的农业系统的能值流动,评价了该县自然环境生产和社会经济发展,为其制定可持续发展战略提供科学的指导。     

基于能值理论的盐城市农业生态系统动态分析

农业生态系统是人类生存的最基本系统,对其结构和功能进行分析是解决农业生态环境问题的关键。应用能值分析理论与方法,对盐城市1995—2010年的农业生态系统能值结构进行了动态分析,采用净能值产出率、能值投入率、环境承载力、能值密度、人均能值用量及可持续性指数对该地区的能值结构进行了详细研究。结果表明:系统能值总投入呈上升趋势,在能值投入中,风能资源投入逐渐增加,但总体比重不高,劳力能值投入受乡镇企业发展和进城务工因素影响逐年下降,以劳力和畜力等有机辅助能为主的传统农业正逐渐被以农机、化肥等工业辅助能为主的现代农业所替代。系统能值总产出呈上升趋势,农业产业结构由以种植业、畜牧业为主向高附加值的畜牧业、水产业的多样化方向转化。系统能值可持续发展指标为0.97,是典型的消费型生态系统,产出的能值是消耗较多的资源获得。系统对于环境的压力较大,可持续性较低,应进一步调整农业产业结构,依靠科学技术,大力发展绿色和生态农业,保护环境资源,实现盐城城市农业生态系统的可持续发展。     

基于能值理论的农牧交错带两个典型县域生态经济系统的耦合效应分析

农牧交错带生态经济系统耦合效应与区域经济的可持续发展紧密相关，该文运用能值理论与方法，首次提出了农牧系统耦合度的概念，并对农牧交错带两个典型县域的农牧系统耦合现状进行了分析。结果表明农牧耦合效果不好，主要表现为两种典型结构模式，一种以安塞县为代表，农牧能值总体利用率较高，但畜牧业内部结构偏重食粮动物使得高质能转化率低下；另一种以武川县为代表，农牧业结构总体上朝趋于协调方向发展，但畜牧业规模过大，由于草畜平衡严重失调，导致农牧系统耦合机制难以稳定。该文根据能值指标分析结果，还提出了提高农牧系统耦合的一些措施及关于产业结构调整的探讨。     

基于能值方法的成都平原农田生态系统秸秆循环利用模式研究

本文采用能值分析方法与理论,以成都平原"稻-麦"轮作农田生态系统不同秸秆循环利用模式为研究对象,通过系统定位试验与随机抽样调查,对农田生态系统常规施肥生产模式(CF)、秸秆直接还田生产模式(CFS)和食用菌菌废料还田生产模式(按物质投入量不同分为FR1、FR2和FR3)的能值投入产出进行比较。研究表明:CF和CFS模式不可更新能值投入比例较大,主要依附工业辅助能的投入;不同模式系统的总能值产出量依次为CFFR2CFSFR1FR3,与CF和CFS模式相比,FR1、FR2、FR3模式的产投比相对较大,FR2模式最大,其产投比为2.35。菌废料还田生产模式下农田生态系统有机能值占系统总能值比例较高,系统净能值产出率高,环境负载率较低,环境压力小,可持续发展性能较强,FR2菌废料还田生产模式是最适合成都平原的秸秆循环利用生产模式。     

基于能值分析的西安市3个发展核心区生态健康评价

基于能值分析和城市复合生态系统的理论和方法,从生态环境系统和社会经济系统两方面,对西安市的灞桥区、雁塔区和未央区3个发展核心区2014年的基础数据进行了能值分析,并进行了生态健康评价,以期为研究区可持续发展提供合理的建议和科学依据。通过PSR模型建立了研究区生态系统健康评价指标体系,采用单因子评价模型评价了系统健康指标,运用层次分析法对单项指标进行赋权重,最后用多因子综合评价来衡量了3个发展核心区的生态健康程度。结果表明:灞桥区、雁塔区和未央区的生态健康指数分别为0.704,0.402,0.705,灞桥区生态环境现状较好,但对于不可更新资源的使用较为依赖,不利于该地区的可持续发展,应当有效利用本地资源;雁塔区社会经济发展较好,但实际人口为人口承载量的1.99倍,人为因素的干扰对雁塔区的生态环境有很大影响,该区社会经济发展主要依赖外部输入资源;未央区新型工业园区的建设将绿化与工业生产结合起来,但该区以第二产业为主,依然消耗大量不可再生资源,产生的工业"三废"污染环境,社会经济的发展主要以消耗本地能源为主。     

现代农业生态系统能值演替分析--以河北省曲周县为例

以河北省曲周县为例，研究了现代农业生态系统的能值演替情况。结果表明，曲周农业生态系统年总投入能值和总产出能值均呈增加趋势，其中农业投能以系统以外的化石能投入为主，系统环境资源投能的绝对数也在增加，主要表现在对地下水的开采利用上；总产出能值先以种植业产出能值占绝对优势后演替为农牧结合同时兼顾林业和渔业发展的能值产出形式，但农牧业系统多样性降低；农业发展在全国居于较好水平，仍有较大的发展潜力，但能值产出效率增加幅度减慢，系统连接网络不佳，优势度呈下降趋势，主要表现为林业和渔业的子系统能值产出占总产出的比例太低。     

半干旱退化山区农村生态经济系统能流分析

能流是生态系统的基本功能,是系统结构和功能的综合反映。通过对半干旱退化山区彭阳县崾岘乡中庄村农村生态经济系统的能流进行分析研究,以期探讨出合理的农村生态经济系统结构。通过对中庄示范区具有代表性的5种生态模式进行分析研究,该区农业生态经济系统是以种植业为主的。有机能在系统的能投中占的比例较大,达到系统总投能的88%~94%,有机能的投入中主要以有机肥和饲料为主,有机能的投入远大于无机能,反映了该地区的农业生产水平低下、机械化程度较低。从种植业系统的能流分析来看,是一个能量低投入与高产出的系统,养殖业系统是一个能量高投入与低产出的系统。总体来看,中庄村的农业生态经济系统是一个能量投入大于产出的系统,而且,能量的投入和产出呈反比关系,说明该区农业生产的能量投入水平还很低。     

吉林省西部苏打碱土区地下水的地球化学特征

选择吉林省西部典型苏打碱化土壤地区，对其地下水的基本水化学指标进行了测定，分析了地下水电导率与含盐量、矿化度和离子含量的关系。针对地下水离子组成的特点，对该区地下水的苏打碱化特征进行了分析。最后分别以电导率、矿化度和钠吸附比（SAR）为指标，对该区地下水质进行了初步评价与分级。     

基于能值理论的水土保持生态效应评价——以山西省长治市为例

运用能值理论分析方法,选取2004-2014年的统计数据,对长治市水土流失治理生态经济系统的投入产出能值及主要能值指标进行分析.研究表明:系统能值投入波动较大,整体呈增加趋势,最低值为2008年的3.91×1021sej,最高值为2011年的4.33 ×1021 sej;系统总能值产出呈现整体增加、局部时间段下降趋势,最低值为2010年的5.95 ×1021sej,最高值为2014年的7.62 ×1021sej,其中2大主导产业中畜牧业整体呈增加趋势、农业中蔬菜产量不断增加都说明水土保持措施取得了一定成效;主要能值指标中,净能值产出率均＞1、可持续发展指数1＜ESI＜ 10,说明长治市水土保持措施的合理性与可持续性.能值理论分析表明,长治市水土流失治理生态经济系统的综合水平总体上呈现上升趋势,系统可持续发展状态良好,生态和经济向着平衡方向发展.     

“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.