SH抑尘剂固化建设场地类型土的抗风蚀性能

[目的]评价SH固化建设场地类型土的抑尘效果及其在建设场地中的适用性,为合理有效控制建设场地扬尘问题提供方法依据。[方法]以高分子材料——SH抑尘剂为研究对象,考虑建设场地扬尘来源(即建设场地类型土)、喷洒量、坡度、坡面形态、固化时间及堆土密度等因素,借助PM10及PM2.5指标评价SH抑尘剂在仅固化建设场地类型土表层条件下的抗风蚀性能及其在建设场地的适用性。[结果]SH抑尘剂可在土样颗粒间发挥联接作用,维持土体表面的完整性,有效解决洒水抑尘措施存在的缩裂问题;SH对于建设场地类型土(粉土、粉煤灰、黏性土、碎石土)均具有很好的抑尘效果,喷洒SH抑尘剂后,固化土在九级风力的吹蚀作用下不会造成PM10和PM2.5污染物;SH抑尘剂对于建筑堆土、建筑弃土及裸露地表均具有适用性,坡度、堆土密度、坡面形态不影响SH抑尘剂的渗透固化效果。从抑尘效果和施工经济角度考虑,建议施工时选取SH抑尘剂喷量1.2kg/m2,固化时间3d。[结论]SH抑尘剂可在土体表层形成抗风蚀性保护膜,实现从源头控制建设场地扬尘。     

免耕条件下农田休闲期直立作物残茬对土壤风蚀的影响

为了探讨直立作物残茬防治农田土壤风蚀发生的机理,该文利用风洞试验和野外观测相结合的方法,分析土壤免耕条件下直立作物残茬对农田土壤风蚀的影响.风洞试验研究表明:翻耕土壤地表风速、土壤风蚀侵蚀率均比免耕土壤高,而地表粗糙度免耕明显高于翻耕.在同样风速条件下,翻耕地土壤风蚀侵蚀率是免耕地的3～8.2倍,且随免耕年限的增加,土壤风蚀侵蚀率呈现递减的趋势.留有不同直立作物残茬免耕土壤地表粗糙度草谷子＞草玉米＞莜麦＞油菜,土壤风蚀侵蚀率呈现相反的趋势,地表粗糙度越大,风蚀侵蚀率越小.野外观测结果表明,不同直立作物残茬对裸露农田的保护作用草谷子＞莜麦＞草玉米＞油菜.风洞试验与野外观测具有相似的试验结论,因此,风洞试验方法可作为测定农田土壤抗风蚀能力的重要工具.     

人工藻结皮对旱区农田土壤风蚀的防控效应

[目的]分析人工藻结皮对土壤起沙风速和风蚀速率的影响及其风蚀防控效果,探索人工藻结皮在农田土壤风蚀防控中的可行性,为农田土壤风蚀防控提供新思路。[方法]研究了400,600,800,1 000,1 200 ml/m²共5个藻液接种量对农田土壤藻结皮形成的影响,进而采用风洞试验,研究人工藻结皮对土壤风蚀的防控效应,探讨了该技术应用于农田土壤风蚀防控的可行性。[结果]在室外自然环境条件下,通过接种藻液可形成不同盖度的藻结皮。藻接种量为1 200 ml/m²时,培养14 d盖度可达30%,50 d后,其盖度可达60%以上,藻生物量、结皮厚度是对照的52和9倍,均有显著差异(p<0.05)。人工藻结皮可显著提高农田土壤的起沙风速,降低风蚀速率。当藻结皮盖度为30%左右,起沙风速(9 m/s)较裸土增加44%,风蚀速率较裸土降低80%以上。[结论]通过在农田土壤接种藻液形成藻结皮,可显著改变土壤物理属性,增强土壤抗风蚀性。农田土壤接种藻液形成藻结皮可以作为一种快速、有效的方法应用于农田土壤风蚀防控。     

沙区旱垄作对油菜生长环境的影响

垄作是沙区旱作农田常用的集水防风耕作技术。本文通过野外试验观测和土壤样品分析,对不同结构的垄作与平作下油菜生长环境进行了研究。结果表明,垄作相对于平作增加了生长季内土壤耕作层水分含量,降低了其波动幅度,改变了土壤水分在垂直剖面上的分布,使湿润锋位于耕作层,有利于油菜对土壤水分的吸收,对缓解干旱对作物生长的胁迫有积极作用。垄作下土壤易蚀性颗粒含量降低,地表粗糙度和垂直风速梯度增大,有效降低了土壤可蚀性和近地表风速,对防治土壤风蚀和保护作物幼苗有重要作用。不同结构的垄作比较,垄高15 cm、垄沟比1/12和垄高25 cm、垄沟比1/24的两种垄作在油菜生长季内集水效果较优,而垄高25 cm、垄沟比1/6的垄作在农田休闲期内防治风蚀效果较好。故结构合理的垄作是沙区旱作农田微观土地利用结构调整的有效措施。     

醋酸乙烯酯类固沙剂固沙效果的风洞实验

通过室内风洞模拟实验,研究了不同净风、挟沙风风速和沙面坡度条件下3种醋酸乙烯酯类固沙剂(WGS-3、WGS-4和CS-204)不同喷洒浓度时的土壤风蚀控制效果。研究结果表明:3种固沙剂均具有较好的抗风蚀能力,相同条件下,固沙剂CS-204的抗风蚀性能稍强于WGS-4,WGS-3的抗风蚀性能相对较差;与净风相比,挟沙风更易使喷施固沙剂后的沙面产生风蚀;挟沙风条件下,沙面累积风蚀量随固沙剂使用量的增加而减小,随沙面坡度的增加而增大;从经济意义上考虑,建议固沙剂WGS-3喷洒浓度稍高于3.0%,WGS-4和CS-204使用浓度为2.0%~3.0%,且喷洒量为1L/m2,能有效固沙。     

地表覆被因子对华北寒旱区土壤抗风蚀力的影响

为了明晰不同类型土壤的抗风蚀力特征与华北寒旱区农田地表覆被因子减降土壤风蚀的效果,采用国家发明专利"土壤风蚀测定装置",通过室内模拟与田间实证研究,分析砂砾、垡片覆被以及耕作措施、残茬存留等地表覆被因子对不同类型农田土壤抗风蚀力的影响。结果表明,砂质栗钙土抗风蚀能力高于壤质草甸栗钙土,在连续吹蚀下地表土壤吹蚀量呈"L"形下降特征;砂砾与垡片覆被可显著增强土壤抗风蚀能力,随覆被度增加土壤吹蚀量呈近线性指数型下降特征。华北寒旱区多年免耕的燕麦留茬农田,地表土壤吹蚀量较传统翻耕田降低70.28%～88.42%,多年免耕的地表砂砾覆被对增强砂质栗钙土农田的抗风蚀力起重要作用;而留茬覆被的粗糙度效应对增强壤质草甸栗钙土农田抗风蚀力更为重要。壤质草甸栗钙土秋耕立垡覆被,较传统翻耕田地表土壤吹蚀量降低92.21%。研究表明,生物性残茬覆被、非生物性砂砾与垡片覆被具有显著提高土壤抗风蚀力效应;在华北寒旱区农田,燕麦留茬免耕覆被可显著降低土壤吹蚀量;对无植被存留条件的壤质草甸栗钙土农田,秋耕立垡覆被同样具有显著提高土壤抗风蚀力效果。     

麦茬深松地表土壤风蚀试验研究

以内蒙古自治区武川县上秃乡保护性耕作农田地表土壤为研究对象,利用移动式风蚀风洞对麦茬深松农田地表进行土壤抗风蚀效果测试研究.研究结果表明,麦茬深松农田地表相对传统耕作地表可降低近地表风蚀土壤量,对土壤输沙影响显著.该研究可为防治农田土壤风蚀提供理论依据     

有机肥与覆盖方式对滩涂围垦农田水盐与作物产量的影响

针对土壤盐碱障碍因子普遍存在于新围垦滩涂农田并严重抑制作物生长的问题,设置了有机肥(鸡粪堆肥)、薄膜覆盖、秸秆覆盖及有机肥+薄膜覆盖、有机肥+秸秆覆盖组合措施,研究其对土壤水盐的调控作用与对作物生长的促进效应。结果表明:各调控均有利于滩涂围垦农田土壤水盐环境的改善、作物的生长,并整体表现出组合措施优于单项措施、秸秆覆盖优于薄膜覆盖的趋势。其中,有机肥+秸秆覆盖组合措施为调控措施中的优化处理,表现在土壤含水量高、土壤电导率与pH值低,作物产量高,增产率达100%以上。单施有机肥虽能增加土壤含水量、降低土壤pH值,但其土壤电导率升高了11.56%,产生了一定的次生盐渍化风险,与覆盖措施的组合能有效控制土壤盐分的表聚,使其显著低于对照,从而保证了有机肥的持续使用。该研究表明,有机肥与覆盖传统农艺措施的有效组合可较好地调控滩涂围垦农田土壤水盐,促进作物增产,该研究为苏北滩涂新垦农田盐碱障碍因子的消减及作物增产提供了一种新途径,也为当地有机肥及秸秆资源的可持续利用提供了依据。     

基于粒度对比法的坝上农田风蚀与粉尘释放量估算

为了计算当前年内的农田风蚀量,该研究利用农田耕作层土壤粒度组成较均一,风蚀使表层可蚀性颗粒减少,不可蚀颗粒含量相对增加这一特点,通过比较一个风蚀季结束后,农田耕作层表层与下层可蚀性颗粒与不可蚀颗粒相对含量的变化,提出了一种估算当前年内土壤风蚀量和粉尘释放量的方法,并给出了风蚀量与粉尘释放量的计算公式。利用此方法对河北坝上地区主要农田类型土壤风蚀量和粉尘释放量进行计算。计算结果表明,2013年研究区农田风蚀量为960～5700 g/(m2·a),平均为2852.14 g/(m2·a),平均风蚀深度为0.21 cm/a,从强度上划分属于重度风蚀。农田平均粉尘释放量为768.16 g/(m2·a),约占农田平均风蚀量的29.00%。粉尘释放量与风蚀量之间有显著的线性相关关系,翻耕耙平地的风蚀量和粉尘释放量显著大于留茬地。该方法的估算结果与前人采用其他方法得到的结果以及实地观测得到的结果基本吻合。     

广西亚热带岩溶地区石灰性土壤钾素特征研究

试验研究广西亚热带岩溶地区石灰性土壤K素特征结果表明,该区农田生态系统中棕色石灰土速效钾含量和速效钾可释放量能较好地反映土壤对当季作物的供K能力;当土壤速效钾含量降至30~32mg/kg时,作物难以吸收土壤中的K素,严重限制作物生长;土壤主要养分限制因子为土壤缺K,且P、S、B、Zn不足;棕色石灰土缓效钾含量和缓效钾可释放量不能正确反映土壤对当季作物的供K能力,但能较正确反映土壤的持续供K能力。施K有利于维持土壤K素平衡,通过增施K肥获得作物高产可行。     

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。     

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.     

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,     

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.     

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.     

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,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.