Microbial use of organic amendments in saline soils monitored by changes in the C/C ratio

An incubation experiment was carried out to investigate whether salinity at high pH has negative effects on microbial substrate use, i.e. the mineralization of the amendment to CO₂ and inorganic N and the incorporation of amendment C into microbial biomass C. In order to exploit natural differences in the ¹³C/¹²C ratio, substrate from two C₄ plants, i.e. highly decomposed and N-rich sugarcane filter cake and less decomposed N-poor maize leaf straw, were added to two alkaline Pakistani soils differing in salinity, which had previously been cultivated with C₃ plants. In soil 1, the additional CO₂ evolution was equivalent to 65% of the added amount in the maize straw treatment and to 35% in the filter cake treatment. In the more saline soil 2, the respective figures were 56% and 32%. The maize straw amendment led to an identical immobilization of approximately 48 μg N g⁻¹ soil over the 56-day incubation in both soils compared with the control soils. In the filter cake treatment, the amount of inorganic N immobilized was 8.5 μg N g⁻¹ higher in soil 1 than in soil 2 compared with the control soils. In the control treatment, the content of microbial biomass C₃-C in soil 1 was twice that in soil 2 throughout the incubation. This fraction declined by about 30% during the incubation in both soils. The two amendments replaced initially similar absolute amounts of the autochthonous microbial biomass C, i.e. 50% of the original microbial biomass C in soil 1 and almost 90% in soil 2. The highest contents of microbial biomass C₄-C were equivalent to 7% (filter cake) and 11% (maize straw) of the added C. In soil 2, the corresponding values were 14% lower. Increasing salinity had no direct negative effects on microbial substrate use in the present two soils. Consequently, the differences in soil microbial biomass contents are most likely caused indirectly by salinity-induced reduction in plant growth rather than directly by negative effects of salinity on soil microorganisms.     

雪莲资源及应用价值

雪莲是传统珍贵藏药,具有散寒除湿,活血通经,抗炎镇痛等作用。本文论述了青海雪莲植物资源、应用价值以及雪莲的研究概况与发展动向。指出雪莲资源可持续发展及保护措施。     

城市静态小水体生态修复措施与生态服务价值评估研究

城市静态小水体污染是城市环境污染的重要问题之一。针对城市静态小水体的特点,依据稳态转换理论和生物操纵理论,形成适应于城市静态小水体的生态修复措施,并运用于武汉市青山区倒口湖水生态修复工程。工程实施后湖水水质得到明显改善,其中,水体透明度由0.2~0.4m提高至1.0~1.5m,溶解氧浓度由1.82~2.35mg/L上升至5.21~6.28mg/L,CODMn浓度由14.96~16.3mg/L降低至3.56~5.01mg/L,TN浓度由2.61~2.99mg/L降至1.27~1.6mg/L,TP浓度由0.43~0.62mg/L降至0.06~0.12mg/L。进一步对倒口湖水生态系统的供给、调节、文化以及支持4方面的服务价值进行评估,通过对水生态系统服务价值评价指标计算得出,工程实施前后水生态系统服务价值分别为299.34万元和645.62万元,新增服务价值346.28万元。在增量价值中固碳释氧、净化水质指标占比最大,表明在水生系统动植物的协同作用下,倒口湖的水质条件得到明显改善。     

大鳍鱯的消化能力与营养价值

采用常规方法测定了大鳍鳠(Mystusmacropterus)的消化道指数,其比肠长、比胃重、比肠重、比肝胰脏重和比内脏重分别为0.531±0.006、0.014±0.006、0.017±0.003、0.0084±0.0029和0.070±0.011。体重与体长的回归方程Y=0.1238X2.8388(r=0.9949,P<0.01);大鳍鳠的胃、前肠、中肠和后肠中消化液的pH值分别为:3.0～3.8、6.6～7.4、7.2～8.2、7.2～7.9,且消化道各部分具有较高的蛋白酶和淀粉酶活性,蛋白酶的活性为中肠>前肠>肝胰脏>后肠>胃;而淀粉酶的活性则为前肠>后肠>中肠>肝胰脏>胃;全鱼和肌肉中粗蛋白的含量分别为62.09±3.8%和68.28±4.6,粗脂肪含量分别为15.33±1.7和21.87±2.9;肌肉中必需氨基酸的含量占氨基酸总量的40.76%,鲜味氨基酸的含量为总氨基酸量的29.70%。综合肌肉的常规营养成分和氨基酸分析的结果,表明大鳍鳠是一种营养价值较高的优质鱼类。     

Ecological detoxification of methamidophos by earthworms in phaiozem co-contaminated with acetochlor and copper

In view of the ubiquitous co-existence of methamidophos, acetochlor and copper (Cu) in agricultural soils, ecological detoxification of methamidophos in phaiozem by earthworms was examined using the detoxic incubation experiments with illumination. It was validated that the earthworm Eisenia fetida is a useful soil animal in the process of methamidophos detoxification as the assistance of soil microbes and enzymes. Due to the action of earthworms, the half life of methamidophos with concentration of 15 mg/kg in phaiozem could decrease from 5.61 days to 5.08 days. Dynamics of methamidophos detoxification by earthworms could conform to the logistic model. Under the condition of multiple pollution combined with acetochlor (20 mg/kg) and Cu (300 mg/kg), ecological detoxification of methamidophos by earthworms became complicated. Acetochlor played a promoting role in the biodegradation of methamidophos to some extent, while it was basically inhibited by Cu.     

黄河水源区首曲湿地草地生态系统服务价值初步估算

黄河水源区首曲湿地保护区的草地生态系统不仅是当地经济社会可持续发展的资源保障,也是黄河上游地区天然的生态屏障。参照国内外草地生态系统服务价值的评估方法,对玛曲草地生态系统的服务价值做了初步估算,以便为草地资源的合理开发、利用及管理提供科学的参考依据。研究结果表明:首曲湿地保护区的草地生态系统服务价值为55.76~71.54亿元/a,是所在地玛曲县生产总值的15~19倍,单位国民生产总值(GDP)的环境成本均高于全国和全球水平。高额的环境成本,是造成该保护区草地大面积退化的主导因素。因此欲从根本上解决草地退化问题,必须转变草地粗放经营模式,实施高效集约化畜牧业生产模式和草地资源管理模式。     

保水剂对混剂土特性的影响

为了解保水剂施入土壤后对土壤性质的影响,促进保水剂在抗旱节水中的合理应用。在河北农业大学实验基地,对青海“绿宝”公司提供的3种剂型保水剂施入土壤后的混剂土进行土壤水分常数、密度、pH值、土壤膨胀率和土壤硬度等性能测定。结果表明：保水剂能显著提高土壤中的土壤水分常数和土壤孔隙度,但混剂土的土壤密度减小;保水剂能明显提高土壤的膨胀性能65％-170％;保水剂加入土壤后对土壤的pH值影响较小;在土壤大量失水后,保水剂能明显降低土壤坚实度,对照土壤的硬度是混剂土硬度的5．2—32．9倍。     

靖远县不同前茬复种蔬菜效益对比

在靖远县开展的不同前茬复种蔬菜效益对比试验结果表明,与单种小麦相比,单种针叶豌豆的产量略低,但产值较高、成本投入较低,是比较理想的复种前茬。针叶豌豆茬的蔬菜产量普遍高于小麦茬,其中大白菜增产15.33%,青萝卜增产23.55%,甘蓝增产15.21%。豌豆茬较小麦茬复种大白菜增收54.02%,复种青萝卜增收36.25%,复种甘蓝增收55.19%。豌豆茬复种蔬菜比小麦茬既增产又增收,是最佳模式。     

玉米收获机茎秆切割铺放装置的设计与试验

随着畜牧业和工业的发展,农作物秸秆作为重要的饲料与工业原料,其需求越来越多,玉米秸秆的回收利用更是受到人们的广泛关注。为此,设计了一种新型的玉米收获机茎秆切割铺放装置,能够实现玉米茎秆的切割、压整和铺放。经田间试验证明,该装置效果良好,切断的茎秆能够满足打捆要求。     

1976-2011年博斯腾湖小湖区湿地生态系统服务价值变化分析

以1976年、1990年、2002年和2011年4期的遥感影像资料为基础,结合野外实地调查及其他相关资料,研究了1976-2011年博斯腾湖小湖区湿地面积和生态系统服务价值变化及其影响因素.结果表明:(1)近40年间小湖区湿地面积变化呈波动性趋势.其中1976年湿地面积最大为3 813.12 hm2;2002年和2011年湿地面积分别减少为3 138.12,2 285.53 hm2.(2)在整个研究时段博斯腾湖小湖区湿地生态系统服务价值的变化整体上呈减少趋势:其中在1976 1990年,年平均减少2.67％;而在1990-2002年,年平均增长2.63％;2002年以后不断减少,减少速度比前15年明显加快.从研究区各生态功能服务价值对总的生态系统服务功能价值的贡献来看,废弃物处理、水涵养和气候调节功能服务价值的贡献率较大,且在整个研究时段呈增加的趋势.在研究期间,博斯腾湖小湖区湿地面积和生态系统服务价值的变化与流域自然和人为因素密切相关,应重视近年来人类活动的负面影响,对绿洲经济活动进行合理规划和控制.