生物基复合改良剂对滨海盐渍土综合地力的提升作用

[目的] 研究生物基复合改良剂对黄河三角洲和苏北滩涂盐渍土壤理化性质及微生物区系的影响,为该区域盐碱地的改良利用和实现生态农牧建设提供科学参考。[方法] 采用由蚯蚓粪、活性酶调理剂和内生菌根菌剂组成的生物基复合改良剂为试验材料,研究其在种植耐盐苜蓿条件下对黄河三角洲盐渍土、苏北滩涂盐渍土土壤理化性质和微生物区系的影响。共设置了4个处理：黄河三角洲盐渍土不添加改良剂和添加改良剂,苏北滩涂盐渍土不添加改良剂和添加改良剂。[结果] 在紫花苜蓿分枝期,与不添加改良剂相比,黄河三角洲和苏北滩涂两种盐渍土壤添加改良剂处理的土壤有机质含量分别增加了45.30%,32.45%;速效钾含量分别增加了41.00%,39.92%。在紫花苜蓿现蕾期,与不添加改良剂处理相比,黄河三角洲和苏北滩涂两种盐渍土壤添加改良剂处理的土壤全盐量分别降低了14.10%和27.85%;土壤有机质含量分别提高了51.99%,73.59%。此外,现蕾期的土壤微生物群落多样性指数明显增加,优势菌门主要为变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、酸杆菌门(Acidobacteria)、浮霉菌门(Planctomycetes)和放线菌门(Actinobacteria)。土壤全盐量和速效钾含量是驱动细菌群落结构变化的主要环境因子。[结论] 生物基复合改良剂可以有效降低土壤全盐量,增加土壤速效养分含量,并改善土壤微生物区系,从而显著提升土壤综合地力,是改良滨海盐渍土的有效措施。     

黄河三角洲环境脆弱带与农业发展研究

本文应用生态环境脆弱带理论,分析了黄河三角洲生态环境的脆弱性。指出脆弱的生态环境是发展农业的一大限制性因素。今后黄河三角洲地区的农业发展,应在保护好生态环境的基础上,走农业可持续发展之路。     

近代黄河三角洲的滨海盐渍土及其开发利用

近代黄河三角洲属近百年来的新成陆地，面积约６７．５×１０４ｈｍ２，大部分为滨海氯化物盐渍土，其中滨海盐土的面积约占６３．７％，土壤盐渍化危害　十分严重．盐渍土资源合理开发利用的途径是实施区域性的分区划类，建成相应的小麦、水　稻、棉花、畜产品及滩涂养殖业等不同类型的生产基地；大力增加土地投入，改善农业装备　；开展必要的基础与应用科学研究，发展可持续农业．     

黄河三角洲不同盐渍化土壤中氨基糖的积累特征

以黄河三角洲垦殖区的轻度和中度盐渍土为研究对象,研究垦殖过程中两种盐渍土氨基糖(氨基葡萄糖、氨基半乳糖、胞壁酸及氨基糖总量)的积累特征,并利用氨基葡萄糖和胞壁酸的比值探讨了真菌和细菌残留物在不同盐渍土有机质积累过程中的相对贡献。结果表明:盐渍化程度对氨基糖总量和单个氨基糖的积累均有显著影响。轻度盐渍土氨基糖含量显著高于中度盐渍土,而不同种类氨基糖含量对盐渍土的响应因微生物来源不同而有所差异。氨基葡萄糖主要来源于真菌,轻度盐渍土中的含量显著高于中度盐渍土。氨基半乳糖的来源并不明确,但与氨基葡萄糖的累积特征相似。胞壁酸唯一来源于细菌,轻度盐渍土中的含量则显著低于中度盐渍土。氨基葡萄糖和胞壁酸的比值在轻度盐渍土中显著高于中度盐渍土,表明与轻度盐渍土相比,细菌残留物对中度盐渍土有机质积累的相对贡献显著增大,也暗示随着盐渍程度加大,细菌逐渐转为优势群体。     

滨海盐渍土适宜土壤盐碱改良剂的筛选研究

针对黄河三角洲地区的实际情况和滨海盐渍土特点,进行利用土壤盐碱改良剂改良盐渍土的研究。引进了4种土壤盐碱改良剂,通过在中度和重度盐渍土上的试验,分析化验土壤含盐量和测定作物产量,对所测定结果进行综合分析,筛选出适宜于滨海盐渍土的最佳改良剂。试验分析结果表明,4种土壤盐碱改良剂都能降低土壤含盐量,其中盐碱土壤修复材料效果最好,是滨海盐渍土适宜的土壤盐碱改良剂。     

黄河三角洲中重度盐渍土棉田水盐运移规律研究

为充分利用黄河三角洲中重度盐渍土资源,通过前期微咸水压盐(2 g/L),选取中度(3.10～3.90 g/kg)和重度(4.60～5.70 g/kg)盐渍土,研究了不同程度盐渍化土壤棉花种植下土壤剖面水盐运移规律。研究结果表明:微咸水压盐后可以使剖面盐分处于相对均匀分布状况;覆盖促进了棉花对膜下水分的吸收利用,中度盐渍土棉花在苗期和蕾期主要耗水层为0～40 cm土壤表层,重度盐渍土棉花主要耗水层为0～30 cm土壤表层,后期由于作物生长引起深层水分(60～100 cm)消耗,且中度盐渍土深层水分吸收要高于重度盐渍土;生育期内中度盐渍土盐分上下土层波动范围为0.80～2.00 g/kg,重度盐渍土为2.00～5.60 g/kg,膜下土壤含盐量均要低于膜外土壤含盐量,至收获期中度、重度盐渍土剖面平均脱盐率分别为62.40%和55.83%,棉花产量分别为2 129.76 kg/hm2和823.66 kg/hm2。     

基于聚类分析的土壤盐渍剖面特征及其空间分布研究

通过对黄河三角洲地区典型地块土壤盐渍剖面的聚类分析,研究并总结该地区不同盐分剖面类型土壤含盐量在水平方向以及垂直方向的分布特征和规律,运用该规律对各盐渍剖面类型的空间分布进行了探讨。结果表明:研究区土壤盐分剖面可以明显分为表聚型、底聚型和平均型3类,按照垂直分布特征可将0～180cm土体划分为0～20cm、20～80cm、80～120cm和120～180cm四个层次;研究区土壤含盐量在垂直方向和水平方向上变异较强,总体上盐分分布具有一定的表聚性,且各土层含盐量的规律性可以作为判断土壤盐分剖面类型的依据;受结构性因素和随机性因素的共同影响,各土层含盐量均表现为中等的空间自相关性和相同的空间自相关变化尺度。Kriging插值与空间分析结果表明,微地形和气候条件是影响表层土壤盐分空间分布的主要因素,地下水性质主导深层土壤盐分的空间分布;表聚型盐分剖面是研究区最主要的剖面类型,其次分别为底聚型和均匀型;不同盐分剖面类型的空间分布反映了植被类型和土地利用方式的差异,人为农业措施是形成底聚型与平均型盐分剖面的最直接因素。该研究结果为黄河三角洲地区盐渍土地的分区、改良、管理以及合理利用提供了理论基础和实践依据。     

黄河三角洲盐渍土开发利用与人工草地建植

介绍了黄河三角洲资源优势与存在问题,论述了黄河三角洲盐渍土开发利用的若干看法以及建植人工草地的重要意义、适宜模式与关键问题.     

黄河三角洲地区畜牧业浅析与可持续发展

黄河三角洲地区是最年轻的国土,对盐渍土经过工程措施和生物措施相结合的综合治理和科技攻关的改良,农业生产和畜牧业产值成几倍增长.由于盐碱土缺水荒地多、自然生态环境脆弱、生产能力低下,限制了发展.本文分析了畜牧业发展的有利条件和制约因素,就开发利用的一些基本原则,发展农区畜牧业,草场畜牧业与可持续发展提出了一些建议供大家讨论,以利推动该地区稳定发展.     

黄河三角洲垦利县可持续土地利用障碍因素分析

该文从自然条件因素、环境条件因素、社会经济条件因素中选择了34个影响可持续土地利用的因子，利用隶属度函数对其进行标准化，通过障碍度计算详细分析了黄河三角洲垦利县可持续土地利用的障碍因素。研究结果表明：在34个因子中人均农业总产值、粮食单产、芦苇地占地率、农业用地率、城镇化水平是黄河三角洲可持续土地利用的主要障碍因素，其中芦苇地占地率在1996年以后始终是第一障碍因素，而人均农业总产值的限制主要出现在1998年之前，之后对可持续土地利用未构成障碍；粮食单产和农业用地率的影响主要出现在1996年以后；林草覆盖率、公顷耕地农机总动力和农村电气化水平在一半以上的年份对可持续土地利用构成障碍；在1994年之前，农民人均收入障碍度较大，是主要的障碍因素。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

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 from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

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 from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

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 from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

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.     

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.