蚯蚓仿生注液沃土装置设计与试验

蚯蚓吞噬土壤,构建洞穴,发挥了肥沃土壤的重要作用。该文借助工程仿生技术手段,运用计算机图像处理技术对蚯蚓头部、体节轮廓图像进行量化分析,提取并拟合蚯蚓头部和体节的轮廓曲线,构建注液沃土装置的仿生几何结构表面。仿蚯蚓背孔排布方式设计了3孔和6孔注液型沃土装置,以UHMWPE为材料制备样机,并采用农机土槽试验系统开展注液沃土装置样机选型试验,考察孔数、是否注液、材料、表面结构4个参数对工作阻力和土壤粘附量的影响。试验结果表明,各参数对工作阻力的影响程度依次为:注液孔数材料表面结构;对土壤粘附量的影响程度依次为:表面结构孔数材料注液。从8类样机中确定的优选类型为:有6个注液孔、UHMWPE材质且具有仿生几何结构表面的仿生注液沃土装置。对选定的样机进行验证,结果表明:在相同试验条件下,该样机的平均工作阻力为283.48 N,平均土壤粘附量值为10.93 g,均低于其他类型样机。该研究工作可为实施机械化沃土工程提供技术参考。     

设施番茄和黄瓜田土壤中农药残留及其对蚯蚓的急性风险

为评价设施蔬菜田土壤中残留农药对蚯蚓的急性危害风险,在山东省济阳县蔬菜基地,分别选择番茄和黄瓜连作种植区,于产中、产后及后茬产中三个时期采集耕层土壤,应用超高效液相色谱串联质谱法评估土样中噻虫嗪、噻虫胺、多菌灵、吡虫啉、阿维菌素、噻唑膦、甲基异柳磷、克百威和三羟基克百威的残留,并通过风险商值法评价其对蚯蚓的急性风险。结果表明:在39个设施番茄土壤中,噻虫嗪、噻虫胺和吡虫啉的检出率(检出浓度均值)均较高,分别为90%(0.107 mg·kg~(-1)dw)、79%(0.100 mg·kg~(-1)dw)和49%(0.233 mg·kg~(-1)dw);在30个设施黄瓜土壤中,噻虫嗪(63%,1.18 mg·kg~(-1)dw)和吡虫啉(57%,0.126 mg·kg~(-1)dw)的检出率和检出浓度均值均较高。在95%的番茄土样及97%的黄瓜土样中,目标农药对蚯蚓的急性风险商值小于1。在3例土壤中发现风险商值大于1,包括2例吡虫啉和1例噻虫胺,应用风险商值逆推,吡虫啉和噻虫胺对蚯蚓的土壤安全阈值分别为1.07和0.593 mg·kg~(-1)dw。研究表明,所调查区域设施蔬菜土壤中目标农药对蚯蚓的急性风险总体较低,对于高风险农药应监测其土壤残留浓度,确保低于安全阈值。     

蚯蚓和细菌对秸秆混粪改良苏打盐碱土碳转化及微生物群落的影响

为了促进苏打盐碱土中有机物料的转化,优化微生物群落结构,提高有机碳含量,利用蚯蚓（Pheretima guillelmi）和外源微生物（类芽孢杆菌C1）研究二者在单一或联合作用下对苏打盐碱土中水稻秸秆和牛粪混合物的降解、有机碳转化以及土壤微生物群落结构的影响。结果表明,蚯蚓、菌株C1单一和联合作用下,水稻秸秆和牛粪混合物的降解率分别提高了66.0%、40.9%和72.1%,土壤有机碳（SOC）含量分别增加了65.8%、18.2%和25.5%,水溶性有机碳（WEOC）含量分别提高了63.5%、1.6%和26.3%。蚯蚓、菌株C1单一和联合作用均能使WEOC的前体物从植物源向微生物源转化,从而增加类溶解性微生物代谢产物的比例;蚯蚓还可以促进WEOC中类腐植酸物质的生成,降低土壤的老化程度,并且与菌株C1之间存在协同效应。蚯蚓、菌株C1单一和联合作用均能够增加真菌的丰富度、多样性以及具有纤维素降解能力的子囊菌群的相对丰度。在属水平上,蚯蚓的作用与土壤中SOC、WEOC含量和WEOC紫外吸收特征值呈正相关。研究表明,蚯蚓与菌株C1单一或联合作用能够使土壤微生物群落结构向更有利于有机物料转化的功能方向转变,进而促进有机物料的降解,提高SOC的含量和稳定性。因此,蚯蚓和菌株C1在苏打盐碱土改良方面具有重要的应用潜力。     

Study of cadmium (Cd)-induced oxidative stress in Eisenia fetida based on mathematical modelling

As a sensitive biological indicator, earthworms are widely used to monitor various pollutants of soil and provide an early warning for soil pollution. However, because many indices are involved in the exposure-induced oxidative stress response, practical applications of these indices are quite inconvenient. Therefore, it is appropriate to investigate the key monitoring index for use in early warning and pollution monitoring. Using Eisenia fetida as an experimental model in an indoor simulation experiment, the mathematical modelling of the effect on oxidative stress in earthworms under cadmium (Cd) stress was studied. The test lasted 40 d, with the removal of one earthworm every 10 d. The Cd²⁺ concentration gradient was set as 0, 1, 10, 20, 100, 200, 400, and 800 mg kg^-1 dry weight. The earthworms were divided into two sections from the clitellum for the determination of total protein (TP) and peroxidase (POD), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GPX), catalase (CAT), malondialdehyde (MDA), and acetylcholinesterase (AChE) activities. Results showed that POD was the key index of oxidative stress in head tissues after 10 d of exposure, TP was the key index at 20 d, and POD became the key index again at 30 and 40 d. By contrast, in tail tissues, MDA and SOD were the key indices at an exposure time of 10 d, GPX at 20 d, CAT and TP at 30 d, and POD and MDA at 40 d. These results contribute to establishing a scientific method for ecotoxicological diagnosis and revealing the mechanism of soil Cd toxicity.     

Behavior and respiration responses of the earthworm Eisenia fetida to soil arsenite pollution

Soil arsenic (As) pollution from mining and industrial sources is a serious issue in China. Earthworms are considered ecosystem engineers and contribute to soil fertility development and maintenance of soil physico-chemical properties. In this study, earthworms were exposed to soils with different sodium arsenite concentrations (0, 5, 20, and 80 mg As kg^-1) for 60 d to investigate the changes in soil properties and the responses of the earthworms (e.g., burrowing activity and respiration). Earthworm burrowing activity decreased with increasing arsenite concentrations, and earthworm respiration was significantly lower in soils with 20 and 80 mg As kg^-1 compared to 0 mg As kg^-1. Changes in soil properties were also observed after incubation of As-amended soil with earthworms. Specifically, soil pH decreased, while soil electrical conductivity and contents of soil NH₃^--N, Olsen-P, and available K increased. Our results suggest that arsenite negatively impacts the metabolic activity of earthworms, leading to reduced burrowing activity, which in turn modifies the effects of earthworms on soil fertility and remediation.     

Earthworm populations are stable in temperate agricultural soils receiving wood-based biochar

The application of decomposable organic residues such as manure and crop litter is generally beneficial to earthworms. There is an emerging interest in applying biochar, a carbonaceous product of pyrolysis, to temperate agricultural soils. The slow decomposition rate of biochar, which also contains ash and combustion byproducts, could be detrimental to earthworms. The objective of this study was to describe the earthworm populations in biochar-amended soils on a dairy farm in the St. Francis River watershed, Quebec, Canada. Earthworms were collected from replicated field plots under cereal production. Site A received three wood-based biochar types at two application rates(5 and 10 t ha~(-1) biochar) plus an unamended control, while Site B received wood-based biochar(7.5 t ha~(-1) biochar), dairy cattle slurry(10 t ha~(-1) manure), or a combination of the biochar and manure rates plus an unamended control. Earthworms were collected by hand sorting and formaldehyde expulsion from soil pits. Three species, Aporrectodea turgida, Aporrectodea tuberculata, and Lumbricus rubellus, were found at the sites, and Aporrectodea was the dominant genus. Biochar sources, rates, and application with dairy slurry did not affect the earthworm population, which had 52–218 individuals m~(-2) in 2010 and 4–96 individuals m~(-2) in 2011. The seasonal variation in earthworm population may be due to flooding in the spring of 2011, which apparently interfered with earthworm reproduction. The similarity in earthworm abundance and biomass in plots with and without wood-based biochar leads to the conclusion that earthworm populations are stable in biochar-amended soils in this cold, humid temperate region.     

蚯蚓磨浆发酵产物减轻苹果连作障碍的机制

  【目的】  探究蚯蚓磨浆发酵产物防控苹果连作障碍的可行性。  【方法】  蚯蚓 (Eisenia foetida) 用湿法磨碎后,加入枯草芽孢杆菌 (Bacillus subtilis) 和黑曲霉菌 (Aspergillus niger) 发酵,发酵物用于试验。盆栽试验土壤采自27年龄的苹果园,供试作物为平邑甜茶幼苗。蚯蚓发酵物施入土壤,在苹果幼苗生长4个月后,调查苹果幼苗的生长状况,分析土壤中总微生物量、致病成分含量和有害真菌数量。  【结果】  施用蚯蚓磨浆发酵产物有效提高了苹果连作土壤中的细菌、放线菌数量,显著降低了真菌数量。与连作土对照相比,施用蚯蚓磨浆发酵产物处理连作土壤尖孢镰孢菌、层出镰孢菌、腐皮镰孢菌和串珠镰孢菌这4种有害真菌分别降低了65.6%、13.9%、84.2%和24.1%;有效降低了连作土壤中酚酸类物质的含量,其中根皮苷、根皮素和对羟基苯甲酸含量分别降低了74.2%、48.9%和67.0%;显著促进了植株根系的生长,提高了根系呼吸速率和抗氧化酶活性,根系呼吸速率、SOD、POD和CAT活性分别提高了69.4%、81.2%、81.1%和161.5%。蚯蚓磨浆发酵产物的添加极大促进了平邑甜茶幼苗植株的生长,植株干重是连作对照CK的2.58倍;同时提高了植株叶片的光合效率及叶绿素含量,其中光合效率比对照提高了46.5%,叶片叶绿素a和叶绿素b含量分别是对照的1.38和1.65倍。  【结论】  蚯蚓磨浆发酵产物的施入可有效提高土壤中细菌、放线菌数量,显著降低真菌数量和有害成分,改善苹果连作果园土壤环境,促进苹果幼树的生长,从而降低苹果连作障碍造成的危害。     

乐果和杀虫双污染对蚯蚓体内蛋白质含量的影响

近年来,土壤环境受到越来越严重的污染,其中一个很重要的原因是农药的滥用造成的,目前农药对土壤动物(尤其是蚯蚓)的影响受到极大重视并成为研究热点.为评价土壤的农药污染程度,选用乐果和杀虫双及其二者复合对蚯蚓进行染毒试验,采用滤纸法研究不同浓度农药污染对赤子爱蚯蚓体内蛋白质含量的影响.结果表明;蚯蚓体内蛋白质含量在乐果污染24h和48 h均比对照显著增加(P＜0.05)、随着乐果浓度的升高,蚯蚓体内蛋白质含量呈现出先增加后降低的趋势,而随杀虫双浓度的升高,蛋白质含量的影响没有明显的规律性;不同浓度处理之间差异显著(P＜0.05),同一浓度处理24 h和48 h之间有极显著的差异(P＜0.01);固定乐果浓度( 60 mg/kg)分别和不同浓度杀虫双处理24 h和48 h,蚯蚓体内蛋白质含量随着杀虫双浓度的升高,均呈现出升高—降低—升高的锯齿型变化曲线,各复合处理之间有显著差异(P＜0.05);回归分析结果表明,蚯蚓体内蛋白质含量与乐果和杀虫双浓度存在一定剂量-效应关系,其关系曲线均为抛物线型,乐果对蚯蚓体内蛋白质含量的影响高于杀虫双.因此可利用蚯蚓体内蛋白质含量的变化较好的指示乐果对蚯蚓的毒性作用,对杀虫双的毒性作用指示效果较乐果差.     

红吼猴粪便沉积物对表层土壤的影响

The short-term influence of dung deposition and the further redistribution of dung by dung beetles were studied under a resting place of the red howler monkey (Alouatta seniculus) living in tropical rainforests of South America. Monkey dung was experimentally clumped on the field in a place used by troops of howler monkeys for resting in the Nouragues Reserve Station, French Guiana. Dung-treated plots were sampled serially over three weeks and compared with controls located in their immediate vicinity. The composition of the soil matrix (top 10 cm) was studied in successive microlayers using an optical method. Under the influence of dung beetle activity, the topsoil became more homogeneous by losing its litter, its content in earthworm faeces increased in the course of time, and surface mineral deposits were penetrated by roots. The results were interpreted in the light of present knowledge on the effects of soil animal activity on plant growth and survival of seedlings.     

饲粮中添加蚯蚓发酵液对安义瓦灰鸡生长性能、肌肉品质、肠道长度及粪便成分的影响

选取320只120日龄安义瓦灰鸡,随机分为4组(每组8个重复,每个重复10只).对照组饲喂基础饲粮(Ⅰ组),试验Ⅱ、Ⅲ、Ⅳ在基础日粮中分别添加2.5,5.0,7.5 μL/g蚯蚓发酵液,试验期42 d.结果 表明:各组安义瓦灰鸡的终末体质量、平均日采食量及平均日增体质量均无显著性差异(P＞0.05),试验Ⅱ、Ⅲ组的料重...