土壤温度和湿度对外来种蚯蚓Pontoscolex corethrurus 产茧和幼蚓孵化的影响

通过采用主处理为土壤温度,副处理为土壤湿度的裂区区组实验设计,在室内微生态条件下控制土壤温度和湿度培养蚯蚓,探讨了3种土壤温、湿度对热带外来种蚯蚓Pontoscolex corethrurus成蚓产茧和蚓茧孵化的影响。研究结果表明,P. corethrurus成蚓在20—30℃土壤温度范围、25%—35%土壤湿度环境中均可持续产茧和孵化幼蚓,培养时间、土壤温湿度对蚯蚓的产茧和孵化呈现显著影响。20%土壤湿度下成蚓休眠或死亡。35%土壤湿度下呈现最大蚓茧产量和幼蚓孵化量。在较好（35%）土壤湿度下产茧数表现为高温好于低温,反之亦然;在适宜（25%—35%）土壤湿度下幼蚓孵化率随温度升高而增加,但呈现高、低温的限制作用,即25℃土壤温度和35%土壤湿度时出现最高幼蚓孵化率。在适宜的土壤温湿度范围内,湿度较温度对蚯蚓繁殖具有更显著的控制作用,温度的影响在一定程度上可通过土壤湿度加以调节。     

温度对赤子爱胜蚓堆肥处理有机垃圾混合剩余污泥效率的影响

为了探讨环境温度对蚯蚓的生物量及其堆肥效率的影响,进行了不同培养温度条件下赤子爱胜蚓堆肥处理有机垃圾混合剩余污泥的研究。试验结果表明,在其他生态因子保持不变的情况下,赤子爱胜蚓的生长和繁殖具有一个适宜的温度范围,可能在20℃左右,温度太高或太低都对蚯蚓的生长和繁殖不利。赤子爱胜蚓对有机垃圾混合剩余污泥的堆肥效率在20℃达到最高,而在其他温度时较低,特别是低温(5℃、10℃)情况下堆肥效率显著降低,但温度较高(30℃、35℃)时其堆肥效率下降不显著。从产业应用的角度,如果同时考虑蚯蚓维持种群繁衍的再生产能力以及蚯蚓堆肥效率这两个因素,环境温度维持在20℃附近可能最适宜赤子爱胜蚓处理有机垃圾混合剩余污泥。     

蚯蚓分离技术的研究

在蚯蚓养殖和利用过程中,如何从大面积的养殖池中把蚓茧、幼蚓、成蚓、饲料、蚓粪分开,提取出成蚓利用;分离出幼蚓喂养;漂浮出蚓茧孵化,这是目前国内外蚯蚓养殖业中尚待进一步解决的技术问题。当前在试验性的养殖     

温湿度对稻纵卷叶螟卵的联合作用

为了探讨温湿度在稻纵卷叶螟Cnaphalocrocis medinalis （Guenée）种群发展中的作用, 通过室内实验调查了不同温度和湿度组合下该蛾卵的发育历期、 胚胎发育情况、 孵化率和卵粒重量的变化。结果表明： 在相同温度下卵历期随相对湿度的增大而缩短, 孵化率随相对湿度的加大而提高。在22℃下低于46%的相对湿度显著降低了卵的孵化率, 而在25～34℃下低于66%的相对湿度会引起孵化率的显著降低, 37℃下卵无论在何种湿度中均不能孵化。在50%左右的低湿条件下, 温度高于28℃后卵也不能孵化。温度在22～31℃和相对湿度在77%～100%范围内, 卵的孵化率无显著差异, 这属于稻纵卷叶螟卵的适宜温湿度范围。稻纵卷叶螟卵的发育起点温度和有效积温分别为10.1±0.6℃和63.7±3.5日度。卵的孵化率（Y）与温湿系数（RH/T）间呈显著的逻辑斯蒂曲线关系Y=0.8662/[1+exp(17.4084-7.5714×RH/T)]。温湿系数在2.34以下时卵孵化率将低于50%, 而达到3.0左右时孵化率接近最高值。结论认为, 低湿造成的稻纵卷叶螟卵重量显著降低、 卵粒干瘪、 胚胎发育受阻是致死卵的主要原因。     

湿度对赤子爱胜蚓产卵包和卵包孵化的影响

在蚯蚓饲养中,饵料湿度对于蚯蚓的正常繁殖和卵包(蚓茧)的顺利孵化,是一个重要因素。这一因素在很大程度上影响着蚯蚓的产卵数量和卵包孵化速度和数量。在天津市饲养蚯蚓所用的饵料,是利用马粪经过高温发酵而成,在饲养过程中,饵料的湿度随饲养床的深度而逐渐增大,但究竟各层的湿度应达到或保持在     

西双版纳热带次生林和橡胶林蚯蚓数量分布及其与环境因子的关系

2006年1月,通过样地调查法比较了西双版纳次生林和橡胶林2种不同土地利用方式的蚯蚓数量分布状况及其与环境因子的关系.结果表明:自然林转变为橡胶林后,土壤养分及植物有机碳输入均明显减少,同时蚯蚓群落发生较大的变化:在橡胶林,热带外来种蚯蚓无围海蚓的密度(52.27 ind·m-2)显著高于林地内本地种蚯蚓远环蚓的密度(0.53 ind·m-2),但在次生林,2种蚯蚓的密度和生物量无显著差异;橡胶林本地种蚯蚓远环蚓的密度(0.53 ind·m-2)和生物量(0.32 g·m-2)与次生林(6.93 ind·m-2、7.76 g·m-1)相比呈下降趋势.无围海蚓的幼蚓在其种群中占有较大比例,类似增长型种群年龄结构,而远环蚓则主要以成蚓为主.相关分析表明,橡胶林的细根生物量与无围海蚓的密度呈显著正相关.由预示蚯蚓群落结构的这种变化可能与橡胶林土地利用引起的植被变化、土壤养分下降等因素密切相关,同时外来种蚯蚓与本地种蚯蚓本身的生态适应对策也不可忽视.     

温度、湿度对黄喉拟水龟胚胎发育的影响

在9种不同温湿度组合条件（25 ℃和-12 kPa、29 ℃和-12 kPa、33 ℃和-12 kPa、25 ℃和-150 kPa、29 ℃和-150 kPa、33 ℃和-150 kPa、25 ℃和-300 kPa、29 ℃和-300 kPa、33 ℃和-300 kPa）下孵化了黄喉拟水龟卵,研究了温度对黄喉拟水龟卵孵出幼体特征的影响及其与湿度的相互作用对孵化期、孵化成功率和孵出幼体特征的影响.结果表明：黄喉拟水龟卵的初始质量、孵化温度、湿度及温湿度相互作用均显著影响孵化过程中卵质量的增加;同一温度下,孵化湿度越高,卵的终末质量越大;而孵化卵的终末质量与孵化温度并不呈线性相关;孵化温度显著影响黄喉拟水龟卵的孵化期,温度越高、孵化期越短,孵化湿度及温湿度相互作用对孵化期的影响不显著;孵化温度和湿度显著影响孵化成功率和卵壳龟裂率;25 ℃和33 ℃处理组孵出幼体中发现畸形个体,而29 ℃处理组中未发现;孵化温度显著影响孵出幼体的质量、背甲长和宽、腹甲长和宽、体高和尾长;孵化湿度只对孵出幼体的背甲长有影响,对其他被检测的幼体特征无显著影响;温湿度的相互作用对所有被检测的孵出幼体特征无叠加或减弱的显著影响.     

体重、年龄和应激刺激对菲牛蛭繁殖性能的影响

采用单因素方差分析等方法探讨人工养殖条件下体重、年龄和环境应激对菲牛蛭繁殖性能的影响。结果表明,体重对卵茧大小和湿质量及幼蛭体长、体宽和湿体质量无显著影响(P>0.05),而亲蛭性腺系数、平均产茧数、孵化率和平均孵化数在各组间差异显著(P<0.05),其中体重10～15g组明显高于其他组(P<0.05);年龄对亲蛭平均产茧数、孵化率、平均孵化数和卵茧大小影响显著(P<0.05),其中2～3年龄亲本具有最高的平均产茧数、孵化率和平均孵化数,8月龄亲本所产卵茧个体明显大于其他年龄组(P<0.05),而卵茧湿质量及幼蛭体长、体宽和湿体质量在各年龄组间均无显著差异(P>0.05)。环境应激对亲蛭的平均产茧数、孵化率和平均孵化数影响显著(P<0.01),其中1～2次操作应激下的平均产茧数和孵化数最高,无操作刺激下的孵化率略高于1～2次操作刺激(P>0.05),而卵茧大小和湿质量及幼蛭体长、体宽和湿体质量在各应激处理组间无显著差异(P>0.05)。本研究获得了菲牛蛭繁殖的最佳体重和年龄,建议繁育生产中挑选10～15g和2～3年龄的个体作为亲本,期间进行1～2次操作刺激可提高其繁殖性能。     

长白山杨桦林不同蚯蚓类群对电击采样的响应及其影响因素

电击法采集蚯蚓对环境相对友好,但电击效率可能因立地条件和蚯蚓类群而变化,进而限制了电击法的广泛应用。本研究于2017年11月上旬采用电击法配合手拣法对长白山3个不同森林发育阶段的杨桦林的蚯蚓群落进行了调查,分析了森林发育阶段、蚯蚓生态型、蚯蚓种群大小以及发育阶段、土壤温湿度状况等对电击效率的影响。结果表明:不同森林发育阶段蚯蚓的电击效率不同,其中40年生杨桦林电击效率最高,其蚯蚓数量和生物量电击效率分别为68.5%和57.4%;表栖型的诺登爱胜蚓(Eisenia nordenskioldi)活动能力最强,电击效率高达100%;内-深栖型的长白山杜拉蚓(Drawida changbaishanensis)在实验期间处于蜷曲休眠状态,电击效率低至0;而内栖型的安德爱胜蚓(Eisenia andrei)的电击效率为22.2%～58.3%;安德爱胜蚓种群大小与电击效率无明显的相关关系(其中,数量:r=0.139,P=0.381,生物量:r=0.025,P=0.877);安德爱胜蚓成体的电击效率显著高于幼体(P=0.014);土壤温度对电击效率有显著的影响,当土壤温度低于6℃时电击效率为0;当土壤温度为6～10℃时,电击效率为34.6%±13.1%,当土壤温度大于10℃时,电击效率为46.0%±8.7%;土壤湿度对电击效率无显著影响。总的来说,电击效率与蚯蚓活动能力的强弱有关。蚯蚓生态型、个体发育阶段及土壤温度在一定程度上影响了蚯蚓的活动能力,进而影响蚯蚓的电击效率。因此,可以根据不同蚯蚓类群活动能力的不同,利用电击法选择性地控制野外蚯蚓群落结构,以开展不同蚯蚓类群生态功能的长期实验研究。     

正颤蚓的生长发育及繁殖生物学的研究

在实验室饲养的条件下,研究了正颤蚓在15℃、20℃、25℃水温的生长发育和繁殖过程。结果表明正颤蚓从其受精卵在蚓茧内发育,孵出生长到产卵,在15℃水温需100—123d,在20℃水温需70—90d,在25℃水温需48—64d。蚓自蚓茧内孵出后的165d生长期内,其15℃、20℃、25℃水温的体重生长回归方程分别是W=6.87/［1+136.48     

菠萝-甘蔗轮作的土壤生态效应

通过2000～2002年进行菠萝-甘蔗轮作田间试验,研究了菠萝、甘蔗轮作对甘蔗土壤生态的影响。结果表明：菠萝甘蔗轮作田与甘蔗连作田比较,能明显地改善土壤的通气和蓄水性,加速速效性养分的释放;增强土壤酶活性;增加土壤微生物总量(一般好气性细菌、真菌、放线菌);有益的氨化细菌和硝化细菌成倍增加,而无益的厌氧性细菌、反硝化细菌则受到抑制;固氮菌数量小且变化不大。菠萝-甘蔗轮作对甘蔗土壤生态环境的改善其实质在于：菠萝、甘蔗轮作后,由于其作物种类的不同导致土壤结构的改善和土壤微生物种类和数量增多,土壤生物活性增强,并导致土壤速效养分的增加。     

连作对三七种子萌发及种苗生长的影响

为进一步明确三七的连作效应,以不同种植年限及不同空间分布的土壤为栽培基质,研究了连作对三七种子萌发及种苗生长的影响。结果表明:连作使三七种子萌发的最大速度增加,种子的发芽势变化不大,而发芽率、发芽指数和快速发芽期则呈明显降低或变短的趋势;与根区外土相比,根区土和根区下土使三七种子的发芽势、发芽率和发芽指数显著降低,对种子萌发的最大速度也有降低的作用;种植1年三七的土壤(1年土)对后茬三七种苗的生长并无明显障碍效应,2年土比3年土具有更强的抑制三七种苗生长的作用。连作对三七种子萌发及种苗生长均会产生明显的障碍效应,自毒作用可能只是造成三七连作障碍的原因之一。     

Links between the detritivore and the herbivore system: effects of earthworms and Collembola on plant growth and aphid development

Effects of Collembola (Heteromurus nitidus and Onychiurus scotarius) and earthworms (Aporrectodea caliginosa and Octolasion tyrtaeum) on the growth of two plant species from different functional groups (Poa annua and Trifolium repens), and on the development of aphids (Myzus persicae) were investigated in a laboratory experiment lasting 20 weeks. Using soil from a fallow site which had been set aside for about 15 years, we expected that nitrogen would be of limited supply to plants and hypothesized that the soil animals studied, particularly earthworms, would increase nutrient availability to plants and thereby also modify aphid reproduction and development. Plant growth was modified strongly by the presence of soil animals. Earthworms caused a more than twofold increase in shoot and root mass of P. annua but increased that of T. repens by only 18% and 6%, respectively. However, earthworms neither affected plant shoot/root ratio nor the nitrogen concentration in plant tissue. In contrast, the presence of Collembola caused a reduction in plant biomass particularly that of P. annua roots, but plant tissue nitrogen concentration was increased, although only slightly. Aphid reproduction on T. repens was lowered in the presence of Collembola on average by 45% but on P. annua increased by a factor of about 3. It is concluded that Collembola decrease aphid reproduction on more palatable host plants like T. repens but increase that on less palatable ones like P. annua. Earthworm presence also affected aphid reproduction but the effect was less consistent than that of Collembola. In the presence of earthworms, aphid reproduction was in one experimental period increased by some 70%. Earthworms also modified the numbers of Collembola and their vertical distribution in experimental chambers. Exploitation of deeper soil layers by H. nitidus was increased but, generally, O. scotarius numbers were reduced whereas those of H. nitidus increased in earthworm treatments. The presence of Collembola also influenced earthworm body mass during the experiment. In general it declined, but in the presence of Collembola loss of body mass of A. caliginosa was more pronounced. We conclude that inhibiting effects between Collembola and earthworms resulted from the use of a common resource, litter material rich in nitrogen. This is supported by the higher C/N ratio of the litter material in the presence of earthworms and Collembola by the end of the experiment. Effects of soil invertebrates like Collembola and earthworms on plant performance and aphid development are assumed to be modified by complex direct and indirect interactions among soil animal groups. Received: 6 July 1998 / Accepted: 1 March 1999     

Degradation and resilience of soils

Debate on global soil degradation, its extent and agronomic impact, can only be resolved through understanding of the processes and factors leading to establishment of the cause-effect relationships for major soils, ecoregions, and land uses. Systematic evaluation through long-term experimentation is needed for establishing quantitative criteria of (i) soil quality in relation to specific functions; (ii) soil degradation in relation to critical limits of key soil properties and processes; and (iii) soil resilience in relation to the ease of restoration through judicious management and discriminate use of essential input. Quantitative assessment of soil degradation can be obtained by evaluating its impact on productivity for different land uses and management systems. Interdisciplinary research is needed to quantify soil degradation effects on decrease in productivity, reduction in biomass, and decline in environment quality throught pollution and eutrophication of natural waters and emission of radiatively-active gases from terrestrial ecosystems to the atmosphere. Data from long-term field experiments in principal ecoregions are specifically needed to (i) establish relationships between soil quality versus soil degradation and soil quality versus soil resilience; (ii) identify indicators of soil quality and soil resilience; and (iii) establish critical limits of important properties for soil degradation and soil resilience. There is a need to develop and standardize techniques for measuring soil resilience. <br>     

Fire and other variables as determinants of forest/fynbos boundaries in the Cape Province

Abstract. Forests in the southwestern Cape are restricted to sheltered stream banks and patches of rock scree owing to protection from recurrent fire and the more favourable soil moisture conditions in these habitats. The effects of a prescribed burn on 17 March 1987 on the forest / fynbos boundaries in the Swartboskloof catchment are described. No evidence of erosion of the forest edge was recorded, although this could be ascribed to the low intensity of the fire. Soil properties, primarily pH and aluminium and available phosphorus levels, differed markedly between forest and fynbos. It is argued, however, that this is a result, not a cause of vegetation change. Light extinction levels and soil moisture availability after the fire were lower in the fynbos than in the forest, and are considered to preclude incursions of forest species into fynbos of a low post-fire age.     

Soil Respiration in the Cold Desert Environment of the Colorado Plateau (USA): Abiotic Regulators and Thresholds

Decomposition is central to understanding ecosystem carbon exchange and nutrient-release processes. Unlike mesic ecosystems, which have been extensively studied, xeric landscapes have received little attention; as a result, abiotic soil-respiration regulatory processes are poorly understood in xeric environments. To provide a more complete and quantitative understanding about how abiotic factors influence soil respiration in xeric ecosystems, we conducted soil- respiration and decomposition-cloth measurements in the cold desert of southeast Utah. Our study evaluated when and to what extent soil texture, moisture, temperature, organic carbon, and nitrogen influence soil respiration and examined whether the inverse-texture hypothesis applies to decomposition. Within our study site, the effect of texture on moisture, as described by the inverse texture hypothesis, was evident, but its effect on decomposition was not. Our results show temperature and moisture to be the dominant abiotic controls of soil respiration. Specifically, temporal offsets in temperature and moisture conditions appear to have a strong control on soil respiration, with the highest fluxes occurring in spring when temperature and moisture were favorable. These temporal offsets resulted in decomposition rates that were controlled by soil moisture and temperature thresholds. The highest fluxes of CO₂ occurred when soil temperature was between 10 and 16 °C and volumetric soil moisture was greater than 10%. Decomposition-cloth results, which integrate decomposition processes across several months, support the soil-respiration results and further illustrate the seasonal patterns of high respiration rates during spring and low rates during summer and fall. Results from this study suggest that the parameters used to predict soil respiration in mesic ecosystems likely do not apply in cold-desert environments.     

Indicator based assessment of the soil compaction risk at arable sites using the model REPRO

Soil compaction impairs all essential soil functions, which are crucial for the lives of humans, animals, plants and soil organisms. In order to secure the various soil functions, soil compaction must be avoided. One successful method of preventing soil compaction could be based on the precautionary principle, and mathematical modelling might be used to support farmers or consultants when making decisions about husbandry operations. This paper presents a model which calculates an indicator and assesses the risk of soil compaction on arable land based on site-specific data including information on soil, weather and specific husbandry. The first step is to estimate the soil strength in response to soil stress for a topsoil (20 cm) and a subsoil (35 cm) layer. The estimations of these parameters take into account changes in soil moisture throughout the year. Soil strength compared with soil stress is used to calculate the indicator Soil Compaction Index (SCI) for each time the machinery passes over the soil. The results from the separate passes are then integrated for a comprehensive assessment of the risk of soil compaction at farm level. The model was validated in numerous trials. It was found that the calculated SCI was a good reflection of the actual change in soil structure. The model is already being applied on arable farms in Germany. As an example presented in this paper, the calculations for the subsoil at these farms result in low to medium compaction risks.     

2013年European Geosciences Union国际会议述评

2013年欧洲地球科学联盟联合大会(EGU会议)于4月7日—4月12日在奥地利首都维也纳举行。会议共设22个分会场,讨论交流地学不同专题领域的最新进展。会议中关于土壤侵蚀模型的探讨主要从模型的新发展、模型的应用和模型的不确定性三个方面展开,强调了不同领域之间的交流与协作,关注了侵蚀模型研究中面临的挑战。对我国土壤侵蚀模型研究的启示主要有以下几个方面：(1)重视对不同尺度、不同类型的侵蚀模型整合技术的研究;(2)加强对土壤侵蚀机理的研究,在此基础上改善模型结构;(3)推进GIS和RS技术在土壤侵蚀研究中的应用,为侵蚀模型研究提供技术支撑。