南方山丘水库种草养鱼防淤减积综合利用的研究

在长沙县百倍冲水库进行多年的试验研究结果表明,开发利用库内长期荒芜的大片消落区种植黑麦草;荒山堤坝上种植扁穗牛鞭草、岸杂一号狗牙根、皇草、幼林间种植鸡脚草、拉丁鲁白三叶等饲草配套养鱼和防止水土流失、防淤减积试验获得成功。库内鲜鱼产量由种草前常年1000kg提高到7000～8000kg,泥砂淤积量每年减少0.516×104m3,经济生态效益显著。     

Postfire Seeding for Erosion Control: Effectiveness and Impacts on Native Plant Communities

Abstract:  Large, high-severity wildfires remove vegetation cover and expose mineral soil, ofen causing erosion and runoff during postfire rain events to increase dramatically. Land-management agencies in the United States are required to assess site conditions after wildfire and, where necessary, implement emergency watershed rehabilitation measures to help stabilize soil; control movement of water, sediment, and debris; prevent permanent impairment of ecosystem structure and function; and mitigate significant threats to human health, safety, life, property, or downstream values. One of the most common postfire treatments is broadcast seeding of grasses, usually from aircraft. Non-native annual or perennial grasses typically are used to provide quick, temporary ground cover to hold soil in place until native plants are reestablished. Critics argue that seeded grasses compete with native vegetation and do not effectively reduce erosion. Few data exist on the effectiveness of erosion control; less than half of the studies I reviewed showed reduced sediment movement with seeding. In all vegetation types, successful growth of seeded grasses—enough to affect erosion—appears to displace native or naturalized species, including shrub and tree seedlings. Due to the competitiveness of seeded grasses, they are used to attempt suppression of noxious weeds in some postfire seeding operations. In burned sagebrush range, postfire seeding is frequently used to replace non-native cheatgrass (  Bromus tectorum ) with native or introduced bunchgrasses, with at least short-term success. In recent years, native species and sterile cereal grains have increasingly been used for seeding. Use of aerially applied straw mulch has increased as well, with the risk of weed introduction from contaminated bales. More research on the effectiveness and ecosystem impacts of these alternatives is needed.     

Plant growth and soil microbial community structure of legumes and grasses grown in monoculture or mixture

A greenhouse pot experiment was conducted to investigate the in?uence of soil moisture content on plant growth and the rhizosphere microbial community structure of four plant species (white clover, alfalfa, sudan grass, tall fescue), grown individually or in a mixture. The soil moisture content was adjusted to 55% or 80% water holding capacity (WHC). The results indicated that the total plant biomass of one pot was lower at 55% WHC. At a given soil moisture, the total plant biomass of white clover and tall ...     

Prospects for Restoring the Biodiversity of Steppe Vegetation: Sowing of Perennial Grasses

Russian Journal of Ecology -     

Does sheep selectivity along grazing paths negatively affect biological crusts and soil seed banks in arid shrublands? A case study in the Patagonian Monte,Argentina

Domestic animals potentially affect the reproductive output of plants by direct removal of aboveground plant parts but also could alter the structure and fertility of the upper soil and the integrity of biological crusts through trampling. We asked whether sheep selectivity of plant patches along grazing paths could lead to negative changes in biological crusts and soil seed banks. We randomly selected ten floristically homogeneous vegetation stands distributed across an area (1250 ha) grazed by free ranging sheep. Vegetation stands were differently selected by sheep as estimated through sheep-collaring techniques combined with remote imagery mapping. At each stand, we extracted 15 paired cylindrical soil cores from biological crusts and from neighboring soil without crusts. We evaluated the crust cover enclosed in each core and incubated the soil samples at field capacity at alternating 10-18 °C during 24 months. We counted the emerged seedlings and identified them by species. Sheep selectivity along grazing paths was largest at mid-distances to the watering point of the paddock. Increasing sheep selectivity was associated with the reduction of the cover of biological crusts and the size and species number of the soil seed bank of preferred perennial grasses under biological crusts. The size of the soil seed bank of annual grasses was reduced with increasing sheep selectivity under both crust and no crust soil conditions. We did not detect changes in the soil seed banks of less- and non- preferred species (shrubs and forbs) related to sheep selectivity. Our findings highlight the negative effects of sheep selectivity on biological crusts and the soil seed bank of preferred plant species and the positive relationship between biological crusts and the size of the soil seed bank of perennial grasses. Accordingly, the state of conservation of biological crusts could be useful to assess the state of the soil seed banks of perennial grasses for monitoring, conservation and planning the sustainable management of grazing lands.     

冷季型草坪草对再生水灌溉响应及适宜性评价

以北京市常见冷季型草坪草多年生黑麦草、高羊茅和草地早熟禾为对象,借助于CAT、POD、MDA、脯氨酸、叶绿素等生理指标,采用室内盆栽的方法研究再生水灌溉下冷季型草坪草的生理反应,及各种生理指标与基质盐分累积的关系,对3种草坪草2种水源灌溉生理适宜性进行综合评价。结果表明:再生水中盐分含量刺激多年生黑麦草和高羊茅体内保护型酶活性保持较高水平,从而保持较强的生理优势,再生水作用使得草地早熟禾生长发育受阻,但盐分不是造成生长受阻的主导因素。在盆栽条件下,不同草坪草对不同灌溉水源生长适宜性由强至弱依次为再生水高羊茅,自来水高羊茅,自来水草地早熟禾,再生水多年生黑麦草,自来水多年生黑麦草,再生水草地早熟禾。     

青藏高原湖泊流域土壤与牧草中多环芳烃和有机氯农药的污染特征与来源解析

2007年8月采集了青藏高原中部与北部6个典型湖泊流域的土壤与牧草样品,分析了样品中多环芳烃和有机氯农药(包括六六六和滴滴涕)的污染水平.土壤样品中Σ16PAHs、ΣHCHs和ΣDDTs的浓度范围分别为60.6~614 ng·g-1(平均194 ng·g-1)、0.06~0.74 ng·g-1(平均0.31 ng·g-1)和N.D.~0.17 ng·g-1(平均0.07 ng·g-1).牧草样品中Σ15PAHs(不包括萘)、ΣHCHs和ΣDDTs的浓度分别为262~519 ng·g-1(平均327 ng·g-1),0.55~3.92 ng·g-1(平均2.17ng·g-1)和0.20~2.19 ng·g-1(平均0.92 ng·g-1),均远低于欧洲高山中相应介质中POPs的浓度.牧草的生物浓缩效应显著,其生物浓缩因子达到4.2~19.3.POPs的浓度分布与有机质/脂肪含量、海拔均无显著相关关系.PAHs的组成以较轻组分(2、3环PAHs)为主,占总浓度的80%以上.PAHs的特征单体比值表明生物质和化石燃料的低温燃烧是青藏高原PAHs的主要来源,同时较低的α/γ-HCH比率和较高的o,p’-DDT/p,p’-DDT比率表明,林丹以及三氯杀螨醇的使用对高原介质中有机氯农药的污染有一定的贡献.根据反向气团轨迹模型,推断冬季青藏高原中部与北部的污染主要受西风带影响,夏季高原中部位点的污染物主要源自印度次大陆,而北部位点还受到中国内陆省份的影响.     

The short term agronomic impact of raising canal water levels in grassland areas: A case study in the Belgian polders

This study tested the hypothesis that raising canal water levels with 30 cm beyond the growing season in intensively managed lowland grassland (2.4-3.7 m above sea level) in Belgium decreases the agronomic value of pastures The study ran 3 years before and 3 years after the water elevation. Using five pairs of plots inside and outside the wetted perimeter, it was not possible to demonstrate significant impacts of the elevated water level on dry matter yield, forage quality, botanical composition, and penetration resistance of the top soil layer of the grassland. In an ex situ lysimeter experiment, simulating the effect of a water level in canals up to 50 cm beneath the surface of the pastures indicated a significant decrease of the penetration resistance of the top soil layer.Results are discussed and confronted with the difficulties of field research addressing the elevation of water levels.     

Analysis of the Factors of Species Association in Serial Communities of Sown Perennial Grasses by the Method of Direct and Indirect Ordination

Russian Journal of Ecology -     

Shoot biomass of turfgrass cultivars grown on composted waste

Various cultivars of four cool-season grass types (tall fescue, fine fescue, perennial ryegrass, and Kentucky bluegrass) were seeded in 0.34-liter plastic pots containing either composted sewage sludge [Com-Til² (CT), Soil Magic² (SM)] or composted yard mulch (YM). Plants were grown in the greenhouse for four weeks prior to measuring shoot biomass. White most tall fescue cultivars showed more shoot growth on YM, perennial ryegrass cultivars generally grew better on SM. Cultivars of fine fescue and bluegrass grew about the same on YM or SM, and slightly less on CT. With very few exceptions, shoot biomass of individual cultivars was greater on either YM or SM than it was on CT. Within individual grass types, Pennlawn (fine fescue), Pennant (perennial ryegrass), and Victa (Kentucky bluegrass) averaged consistently better growth on all three composted media. For tall fescue, Aquara, Rebel II, and Monarch performed best on YM, SM, and CT, respectively. Bioaccumulation of heavy metals did not occur in selective samples of shoot tissues collected from the grass types used. This research was supported by National Science Foundation grant #8902053 to Buckeye Bluegrass Farms. The greenhouse studies described in this paper were performed in conjunction with field tests conducted at Buckeye Bluegrass Farms. Requests for information on field trials should be directed to H. F. Decker, Box 176, Ostrander, Ohio 43061, USA. Use of trade names is for the reader's information only and does not imply endorsement over similar products of like properties.