沼液浇灌对茭白氮磷钾养分吸收利用特性的影响

通过田间试验,研究沼液浇灌量对茭白植株不同生育期氮、磷、钾养分吸收累积以及利用效率的影响。结果表明,当沼液浇灌量为2.0倍（2.0N）和2.7倍（2.7N）对照化肥氮时,茭白植株成熟期磷和钾累积量均受到明显抑制,其中,磷积累量分别下降8.73%和42.0%,钾积累量分别下降16.4%和34.1%;氮累积量仅在2.7N处理时受到明显抑制。2.0N和2.7N处理使茭白植株不同生育期茎秆和叶片氮磷含量整体呈增加趋势,其中27N时尤为明显,然而钾含量反而下降。茭白氮含量随沼液浇灌量增加而增加,钾含量呈先增后降趋势,磷含量变化较为稳定。沼液浇灌处理均抑制了茎秆磷转运,但却促进了茎秆和叶片钾转运。另外,2.0N和2.7N处理明显抑制了叶片氮转运。因此,沼液浇灌能够影响茭白植株对氮、磷、钾养分的吸收累积特性,改变利用效率。适量浇灌有利于提高茭白养分利用效率。     

天津市农村沼气利用现状及发展对策

生物质能源的开发利用,对于建设社会主义新农村、构建资源节约型和环境友好型社会、实现农业的可持续发展具有重要现实意义。从天津市农村沼气主要生物质资源类型、分布、利用现状出发,分析了目前天津市农村沼气生物质资源的现状与开发利用情况,并剖析了目前存在的问题,最后结合现代都市型农业的发展,提出了今后天津市农村生物质能源发展的对策与建议。     

沼液的叶面喷施对玉米产量及效益的影响

为了探明玉米施用沼液的效果,特设沼液喷施、尿素溶液喷施和清水喷施(ck)3个处理进行对比试验。结果表明,沼液喷施、尿素喷施与清水喷施下玉米的产量差异达显著水平(p0.05);沼液喷施的平均增产62.9 kg/667m~2,增产率达13.2%,净增收56.1元/667m~2;尿素喷施则只增产不增收,平均增产为24.0 kg/667m~2,增产率达5.1%,但净增收出现了负值,为-52.8元/667m~2。试验表明合理的利用沼液,对玉米的增产增收有重要作用,应该在生产上大面积推广。     

贮存中的沼液污染因子分析评估

为实现沼液农田安全应用,研究了规模化养猪场沼液在不同贮存时间条件下,有机物和重金属变化规律,并对污染因子进行分析。结果表明沼液中污染物总量随贮存时间增加而下降,主要致污因子为3种有机污染物,5种重金属均无超标,沼液贮存时间大于9天综合污染评价为安全级,且农田应用需兑水稀释。评价结果还为沼气工程的工艺改进提供参考。     

沼液不同施用方式对苹果园土壤及叶片养分和果实品质的影响

陕西目前苹果种植面积位于全国第一,但果园存在的最大问题是基础肥力低,有机肥肥源和施用不足。为探讨沼液作为有机肥在苹果上的合理施用技术,本试验采用叶面喷施、灌施、树干涂抹3种方式进行了沼液在铜川苹果园施用效果的研究,分析了3种施用方式和不同施用量对叶片和土壤养分含量及果实品质的影响。结果表明,幼龄果树和盛果期树每株分别灌施沼液30 kg、60 kg对叶片和土壤养分含量及果实品质影响显著,和对照相比,叶片氮、磷、钾含量分别增加15.66%、134.91%、45.83%(幼龄树)和5.59%、12.43%、28.65%(盛果期树),幼龄树和盛果期树的果实可溶性固形物分别增加了31.33%、27.38%,Vc含量分别增加了53.67%、50.92%。幼龄树喷施1∶2沼液和盛果期树喷施1∶1的沼液效果较好,树干涂抹沼液对叶片营养和果实影响较小。     

不同环境温度下沼液养分在土壤中的淋失模拟研究

沼液因其养分利用率高,被广泛应用于农业生产中,而环境温度可通过影响土壤的物理化学性质,影响沼液养分的淋溶损失。试验采用土柱模拟法,研究了不同环境温度对土壤沼液养分淋溶的影响,旨在揭示不同季节土壤养分淋溶可能存在的差异,为生产中合理施用沼液提供理论依据。土柱规格为内径7.5 cm、高20 cm的聚氯乙烯(PVC)管,按每公顷施入0,130和260 kg N,设置每土柱沼液灌溉总量为0,200和400 mL。按当地年平均降雨量的70%计算实际浇灌量为1500 mL,分5次每隔6 d模拟不同降雨次数进行浇灌。沼液浇灌前用清水补足不足部分并混匀。土柱放置于20和30℃的温室培养,每次淋溶后收集土壤淋溶液,测定其全氮、硝态氮、铵态氮、全钾、全磷、速效磷和电导率。结果表明,施用沼液后淋溶液中氮、磷、钾淋失量较清水对照显著增大,其中40 mL沼液水平下,全氮含量平均增加73%,全磷含量增加880%,全钾含量增加388%,且随着沼液用量的增加淋溶液中的养分浓度呈增加趋势。环境温度的提高增加了沼液养分在土壤中的淋溶损失,30℃时淋溶液中的硝态氮、全氮、全钾、全磷、速效磷含量及电导率整体高于20℃,其中全氮平均提高14.68%,全磷平均提高33.59%,全钾平均提高24.08%。整体而言,30℃下沼液养分较20℃时更易发生淋失。因此,在农业生产中,应适当减少夏季高温时的沼液施用次数,增加春秋季节施用次数,但沼液用量不要超过130 kg N/hm²,防止沼液养分大量流失,污染周边环境。     

Comparison of the effects of six stunning/killing procedures on flesh quality of sea bass (Dicentrarchus labrax,Linnaeus 1758) and evaluation of clove oil anaesthesia followed by chilling on ice/water slurry for potential implementation in aquaculture

The effects of different stunning/killing procedures on flesh quality of European sea bass were investigated: (1) anaesthesia with clove oil, (2) anaesthesia with 2‐phenoxyethanol, (3) percussive stunning, (4) immersion in ice/water slurry, (5) chilling on ice and (6) anaesthesia with clove oil followed by immersion in ice/water slurry. Muscle pH values were significantly lower in sea bass anaesthetized or stunned by a blow to the head compared with fish immersed in ice/water slurry, chilled on ice or immersed in ice/water slurry after clove oil anaesthesia. Lightness was highest in sea bass anaesthetized by 2‐phenoxyethanol or percussively stunned and lowest in ice‐chilled fish. Redness and yellowness were highest in fish chilled on ice and lowest in fish anaesthetized with clove oil. Liquid loss, fat loss and shear values were not significantly different among the procedures. In general, lipid oxidation values during refrigerated or frozen storage did not significantly differ among treatment groups. Combination of clove oil anaesthesia followed by chilling on ice/water slurry appears to improve both flesh quality and welfare of sea bass, although the implementation of further studies is warranted to consolidate this finding.     

A Highly Activated Mineral Admixture Slurry Consisting of a Wet discharged Fly ash and Carbide Lime Composite

To recycle wet discharged fly ash and carbide lime effectively, a highly activated mineral admixture slurry consisting of both these components was investigated. The preparation technology of mineral admixture slurry made from a composite of wet discharged fly ash and carbide lime and the strengths, hydration products change (XRD, SEM) of cement paste made by the slurry were studied. The results indicate that the optimal proportion between wet discharged fly ash and carbide lime (solid content) is 75:25 in the process of wet milling preparation. The alkaline environment provided by carbide lime with high Ca(OH)2content and cement hydration accelerated by modified agents can promote early activation of fly ash, and accelerate its secondary hydration reaction.     

接种物数量对沼气产气量的影响

[目的]探讨发酵条件对产沼气的影响。[方法]以鲜猪粪为原料,采用批量沼气发酵方法,研究了7个处理（接种量分别为7％、14％、21％、28％、35％、42％和49％）对厌氧发酵产气量、产气特性的影响。[结果]结果表明,在常温条件下,不同接种量都能启动产气。接种量在35％～49％时,沼气发酵启动快;接种量在49％时,60d产气量和启动1-10d日均产气量最高,分别为33540ml、851ml／3500耐发酵液,60d产气量方差分析结果表明,49％与28％、35％和42％处理差异不显著。[结论]接种量为28％～35％是沼气发酵产气良好的接种量。     

养猪场粪污治理与再利用研究进展

随着养猪业向集约化、规模化发展,猪场粪污排放过度集中,超过周边环境承载负荷,造成环境污染问题日益严重。本文综述了国内外规模化猪场的粪污处理技术,为规模化养猪场粪污治理与循环再利用模式建立,实现“达标”排放或冲栏回用无排放提供参考。