松嫩平原优势种羊草与其主要伴生种芦苇空间分布格局分析

芦苇是松嫩草地优势种羊草的主要伴生种,两者常常形成物种组成比较单一的混生群落或者与其他物种组成羊草 杂类草群落.选择羊草 芦苇混生群落,羊草群落和芦苇群落的交错区进行羊草、芦苇单物种格局分析.结果表明,1)混生群落和交错区中,羊草和芦苇均是以集聚分布的形式存在;2)羊草在混生群落中的格局强度小于交错区中的格局强度,芦苇在2种类型群落中的格局强度没有显著差异;3)除了考虑物种的生物学特性以外,混生群落种内、种间竞争也是影响羊草集聚分布和格局强度的主要因素,交错区中,环境异质性和种间竞争是影响集聚分布和格局强度的重要因子;4)芦苇在混生群落和交错区中格局强度没有明显差异,由此可以判定芦苇的空间分布格局形成主要受植物本身生物学特性的影响.     

鹰嘴紫云英头茬草生产性能的研究

通过对杨凌地区生长的鹰嘴紫云英（Astragalus cicer L.）的株高、株长、产量、草层结构、鲜干比、茎叶比等的研究表明：生长第二年第一茬初花期时刈割的鹰嘴紫云英平均株高达57 cm,株长达102 cm,鲜草产量达47 077.6 kg/hm^2,干草产量8 702.0 kg/hm^2,其茎、叶主要分布在0～40cm的草层中,茎、叶鲜重分别占到总重量的52.39%和31.88%,鲜干比为5.41：1,茎叶比为1.47：1,属典型的下繁型牧草,具产草量高、营养丰富、牧草品质好等优点,是值得推广的优良牧草.     

不同轮作序列对旱地胡麻土壤有机碳稳定性的影响

为了探索陇中黄土高原半干旱丘陵沟壑区胡麻轮作序列对土壤碳库的影响,2012-2016年通过4年定位试验,以连作为对照,研究了不同胡麻频率下的轮作序列(F:休闲;PWFW:25%Flax、马铃薯-小麦-胡麻-小麦;WFWP:25%Flax、小麦-胡麻-小麦-马铃薯;FWPF:50%Flax、胡麻-小麦-马铃薯-胡麻;WPFF:50%Flax、小麦-马铃薯-胡麻-胡麻;FFFF:100%Flax、胡麻-胡麻-胡麻-胡麻)对土壤团聚体、总有机碳(TOC)、土壤颗粒有机碳(POC)、土壤微生物碳(MBC)和氮(MBN)的影响。结果表明,休闲、不同轮作序列和低胡麻频率显著增加了030 cm土层<0.25 mm粒级的土壤团聚体含量、TOC和POC含量,而随胡麻频率的增加三者的含量呈下降趋势。其中,25%Flax处理下土壤团聚体含量较播前和休闲处理分别显著增加了2.02%4.04%和9.56%11.73%;土壤有机碳(SOC)较连作显著增加5.95%7.48%。50%Flax处理下胡麻位置对土壤SOC影响显著,且轮作(FWPF)显著高于连作(WPFF)。060 cm土层土壤SOC含量表现为休闲>播前≈25%Flax>50%Flax>100%Flax。与连作相比,轮作显著提高了010 cm土层土壤TOC和POC含量,呈现表层富集现象。土壤POC含量表现为25%Flax≈休闲>50%Flax>100%Flax。此外,轮作换茬显著增加了土壤MBC含量,且随着胡麻频率的增加,030 cm土层土壤MBC含量逐渐降低。与播前、休闲、轮作相比,连作显著降低土壤微生物碳氮比,50%Flax(WPFF)轮作序列和土层深度对土壤有机碳和微生物量的互作效应显著。综合来看,休闲可以显著改善土壤理化性状,25%胡麻频率的轮作序列利于保持土壤团聚体稳定性,增加土壤TOC、SOC和POC含量,而50%Flax轮作序列(WPFF)能够提高土壤微生物量和微生物碳氮比。表明25%胡麻频率的轮作序列均可维持土壤有机碳的稳定性,是旱地胡麻比较理想的轮作序列。     

Gas and short‐chain fatty acid production from feeds commonly fed to red deer (Cervus elaphus L.) and incubated with rumen inoculum from red deer and sheep

Efficient red deer supplementary feeding depends on estimations of the nutritive value of offered feeds, frequently estimated with the use of equations derived from domestic ruminants. The aim of this study was to compare the 24‐hour in vitro true dry matter degradability (ivTD₂₄), in vitro gas production (GP) kinetic parameters, GP in 24 hr of incubation (GAS₂₄) and short‐chain fatty acid (SCFA) and microbial biomass (MBS) produced after 24‐hour incubation of feeds in inoculum prepared from sheep and red deer rumen fluid. Eleven feeds, frequently consumed by red deer in Slovenia, which occur either naturally (two fresh grasses, chestnut fruits and common and sessile oak acorns) or are fed as winter supplemental feeds (two grass hays, two grass silages, apple pomace, fresh sugar beetroot), were investigated. The in vitro GP kinetic parameters, GAS₂₄ and ivTD₂₄, did not differ between animal species. Amounts of SCFAs were greater (p < 0.05) when feeds were incubated in sheep inoculum, while molar proportions of acetic and propionic acids did not differ. Molar proportions of butyric acid produced during incubation of high fibre feeds did not differ between animal species, but were higher (p < 0.05) when feeds high in starch or sugar were incubated in red deer inoculum. Greater production of SCFA by sheep rumen microbes suggests better coverage of host animal with energy precursors, while greater production of MBS by red deer rumen microbes suggests better coverage of host animal with protein. Results also suggest that rumens of sheep and red deer are inhabited by different microbial communities, which did not affect the extent of in vitro GP and degradation of feeds used in the present experiment. However, the possibility exists that the divergent nutrient use could be a consequence of different priming by different feeds of the donor animal diets.     

基于冗余分析的高寒草原土壤与草地退化关系

在高寒草原退化草地设置研究样地,观测植物群落特征、采集土壤样品、分析土壤物理化学性质,依据数量生态学基本原理,探讨高寒草原退化草地与土壤因子间关系。结果表明:不同退化程度样地沿冗余分析排序图第一排序轴分布,第一排序轴反映草地退化程度的变化;草地植物群落中与第一排序轴负相关且按相关程度大小排序的指标为盖度>地上生物量>地下生物量;第一、第二排序轴能够解释97.1%的土壤因子与草地退化关系;土壤沙砾、p H与第一排序轴正相关,土壤有机碳、土壤含水量、容重、全氮、有效氮与第一排序轴负相关;第一排序轴及所有排序轴所反映的土壤因子均与草地退化之间呈极显著相关关系(P<0.01);不同土壤因子与草地退化之间相关程度不同,土壤有机碳(r=-0.890)、土壤含水量(r=-0.864)、容重(r=-0.847)、全氮(r=-0.836)、有效氮(r=-0.821)等与高寒草原退化相关程度更高且相关关系极显著(P<0.01)。利用退化草地群落特征和土壤因子数据矩阵进行冗余分析能够较好地综合反映土壤因子与草地退化之间的关系及相关程度,土壤有机碳、土壤含水量、容重、全氮、有效氮是反映高寒草原退化的重要土壤指标。     

Impact on soil physical properties of using large-grain legumes for catch crop cultivation under different tillage conditions

In Central Europe, various plant species including large-grain legumes and their mixtures are grown as catch crops, particularly between grains harvested early and subsequent summer crops. This article investigates the question of how soil structure in the topsoil is influenced when catch cropping with large-grain legumes (experimental factor A: without catch crop, with catch crop) under different ploughless tillage conditions during catch crop seeding (experimental factor B: deep tillage/25–30 cm, shallow tillage/8–10 cm). Five one-year trials were performed using standard machinery at various sites in Germany. Soil core samples extracted from the topsoil in the spring after catch crop cultivation served to identify air capacity, saturated hydraulic conductivity and precompression stress. The above-ground and below-ground biomass yields of the catch crops were also determined at most of the sites. In addition, the soil compaction risk for the working steps in the experiments was calculated using the REPRO model.The dry matter yield of the catch crops varied considerably between the individual trial sites and years. In particular, high levels of dry matter were able to form in the case of early seeding and a sufficient supply of precipitation. The soil structure was only rarely affected positively by catch crop cultivation, and catch crops did not contribute in the short term to loosening already compacted topsoils. In contrast, mechanical soil stresses caused by driving over the ground and additional working steps used in cultivating catch crops often led to lower air capacity in these treatments. This is consistent with the soil compaction risks calculated using the REPRO model, which were higher in the treatments with catch cropping. Catch crop cultivation also only resulted in improved mechanical stability at one location. The positive effect of deep ploughless tillage on air capacity and saturated hydraulic conductivity, however, became more clearly evident regardless of catch crop cultivation. In order for catch crop cultivation with large-grain legumes to be able to have a favourable impact on soil structure, it is therefore important that cultivating them does not result in any new soil compaction. In the conditions evaluated, deep tillage was more effective at loosening compacted topsoil than growing catch crops.     

高温胁迫下AM真菌对牡丹叶片解剖结构和蒸腾特性的影响

作者研究了高温胁迫下丛枝菌根(arbuscular mycorrhizal,AM)真菌对盆栽牡丹幼苗叶片解剖结构和蒸腾特性的影响。结果表明,供试AM真菌摩西球囊霉(Glomus mosseae)和地表球囊霉(Glomus versiforme)均能侵染牡丹根系,其侵染率分别为47%和44%。接种AM真菌的比未接种对照(CK)植株的叶片细胞排列紧密,叶片厚度、栅栏组织和海棉组织厚度均表现为接种G.mosseae植株>接种G.versiforme植株>CK。在相同高温下接种AM真菌处理的牡丹叶片蒸腾速率、气孔导度和气孔开度均显著低于CK。AM真菌提高了牡丹植株的抗热性,这对于高温胁迫下保持和提高光合效率是十分重要的。其中接种G.mosseae处理的效果优于G.versiforme     

广西5种人工林地土壤微生物数量及土壤酶活性分析

为当地珍贵速生树种人工林的发展及合理利用提供理论依据。分析广西5种珍贵树种人工林土壤微生物数量及土壤酶活性差异,以相同立地条件下12年生的黑木相思(Acacia melanoxylon)、老排(Mytilaria laosensis)、红椎(Castanopsis hystrix)、黧蒴椎(Castanopsis fissa)和火力楠(Michelia macelurei)人工纯林为研究对象,采用稀释平板涂布法和土壤酶活性测定法,测定和分析该5种人工林地土壤微生物数量及酶活性。结果表明:5种林地的土壤微生物总数和细菌数量大小均为:火力楠黧蒴锥红椎黑木相思米老排。但5种林地的土壤酶活性大小不一,蔗糖酶、脲酶、蛋白酶、酸性磷酸酶活性在5种林地之间的差异极其显著,而过氧化氢酶活性不显著。5种林地中土壤酶活性相对较强的是米老排人工林,较弱的是黑木相思林和火力楠林。土壤酶活性与微生物数量的相关分析表明,土壤中蔗糖酶活性与放线菌数量呈极显著正相关关系,其余相关性没有达到显著水平。     

一种新型阳光蔬菜工厂C系列919温室

为了解决高寒及长江流域以南多雨地区土墙温室难建问题及实现温室育种、种植自动化、机械化作业,研发了一种新型装配式冬暖式C919温室,温室通过组装完成,采用钢制螺旋桩,不用焊接,只需在地下打螺旋桩,即可实现全天候施工。温室采用五防设计(防台风、防雨、防雪、防低温、防高温),具有土地利用率高(75%左右)、建设周期短(千亩园区建设周期90 d)、设计寿命长(50年)、材料环保(采用宝钢BFS 600高强不锈钢)、建设成本使用周期费用摊销低(土墙温室的70%)、运营维护成本低(土墙温室的50%)、机械作业用工少(减少人工60%以上)等优点,填补了高寒(-40 ℃以内)及长江流域以南多雨地区大跨度、装配式、全日光能源温室的空白。     

Sewage sludge processing determines its impact on soil microbial community structure and function

Composting and thermal drying are amongst the most commonly used post-digestion processes for allowing sanitation and biological stabilization of sewage sludge from municipal treatment plants, and making it suitable as soil conditioner for use in agriculture. To assess the impact of sludge-derived materials on soil microbial properties, fresh (LAF), composted (LAC) and thermally dried (LAT) sludge fractions, each resulting from a different post-treatment process of a same aerobically digested sewage sludge, were added at 1% (w/w) application rate on two contrasting (a loam and a loamy sand) soils and incubated under laboratory conditions for 28 days. Soil respiration, microbial ATP content, hydrolytic activities and arginine ammonification rate were monitored throughout the incubation period. Results showed that soil biochemical variables, including the metabolic quotient (qCO₂), were markedly stimulated after sludge application, and the magnitude of this stimulatory effect was dependent on sludge type (precisely LAT > LAF > LAC), but not on soil type. This effect was related to the content of stable organic matter, which was lower in LAT. Genetic fingerprinting by PCR–DGGE revealed that compositional shifts of soil bacterial and, at greater extent, actinobacterial communities were responsive to the amendment with a differing sludge fraction. The observed time-dependent changes in the DGGE profiles of amended soils reflected the microbial turnover dependent on the sludge nutrient input, whereas no indications of adverse effects of sludge-borne contaminants were noted. Our findings indicate that composting rather thermal drying can represent a more appropriate post-digestion process to make sewage sludge suitable for use as soil conditioner in agriculture.