气候因子和地表覆盖对沿海滩涂土壤盐分动态的影响

为探明气候因子对沿海滩涂表层土壤盐分季节性变化规律的影响,并探讨植被和秸秆覆盖对滩涂土壤脱盐效果及控盐的作用。2014年5月—2015年5月,在江苏沿海滩涂盐碱地(中重度盐分),设置4种处理进行田间试验,分别为对照(裸地,CK)、秸秆覆盖(覆盖量为15 t·hm-2,SM)、植被覆盖(PC)和植被+秸秆覆盖(覆盖量为7.5 t·hm-2,PC+1/2SM),监测了气候因子和表层土壤盐分的季节性动态变化。结果表明:1)在沿海滩涂裸地中,土壤盐分具有一定程度的季节性规律,表现为在10—12月具有明显的积盐效果,且在10月EC1︰5达到最大值为3.90 d S·m-1。2)相关分析表明:采样前7 d降雨累积量与土壤盐分变化有着极密切负相关关系;气候因子的多因子及互作逐步分析表明:降雨量增加可以促进土壤脱盐作用,大气温度升高可加剧土壤盐分表聚,降雨量和大气温度的互作效应增加会对土壤盐分累积产生正效应。3)地表覆盖(包括PC和SM)显著地改变了气候因子对土壤盐分动态变化的影响,累积降雨量和大气平均温度与土壤盐分无显著相关性,且大量秸秆覆盖对滩涂表层土壤脱盐具有更明显的效果。因此,在沿海气候向暖湿方向发展的趋势下,综合考虑脱盐及控盐作用,选择适量秸秆覆盖(如覆盖量15 t·hm-2)或适量秸秆覆盖结合植被种植覆盖,同时充分利用沿海地区降雨量集中的特点,可能是未来滩涂盐碱盐渍土快速脱盐和土壤改良的重要措施。     

滴灌条件下排水暗管埋深及管径对土壤盐分的影响

为探索高效节水的暗管排盐技术,通过田间灌溉排水试验,研究了滴灌条件下排水暗管不同管径(50、90 mm)、和不同埋深(0.6、1.0、1.4 m)对土层含盐量分布及脱盐效果的影响。结果表明:两次灌水后各土层脱盐效果差别较大。0~60 cm土层脱盐程度较高,土壤含盐量已降至12 g kg~(-1)以下中度盐化水平,100 cm以下土层脱盐效果不明显;暗管0.6 m埋深脱盐效果优于1.0、1.4 m埋深,总体盐分减少14.34 g kg~(-1),相比未铺设暗管对照减少了13.32 g kg~(-1)。增加暗管埋深至1.4m对暗管降盐效果无显著影响;暗管管径对各土层盐分的影响相对更加显著,90 mm管径相较50 mm管径暗管脱盐效果明显,50、90 mm管径暗管不同埋深0~1.4 m土层脱盐率分别在20.69%~30.20%和34.59%~57.04%之间。暗管埋深0.6 m、管径90 mm时,两次灌水后0~60 cm土层已降至轻度盐化水平(3~6 g kg~(-1)),暗管排水排盐效率较高,为北疆盐渍土的暗管排水最优埋深与管径布设参数。     

凡纳滨对虾家系幼虾淡化和养殖阶段存活性状遗传参数估计

准确估计育种目标性状的遗传参数,评估其改良潜力,是制定育种方案、进行选择育种工作的重要前提条件。本研究对100个凡纳滨对虾(Litopenaeus vannamei)家系15000尾仔虾个体进行淡化和低盐养殖实验,分析了2个阶段家系间存活率的差异,并进一步估计存活性状的遗传力。结果显示,2个阶段存活率范围分别为19.3%~100.00%和11.86%~99.22%,平均存活率分别为66.7%和67.5%。家系幼虾期总体存活率为6.67%~90.67%,平均存活率为46.91%。统计分析显示,2个阶段家系间存活率差异极显著(P0.01),存活率的相关系数为0.61(P0.01),呈中度正相关(0.3r0.8)。利用加性效应(A)和加性+共同环境效应(A+C)模型分别估计了淡化、低盐度养殖以及合并2个阶段存活性状转换后的遗传力。基于A模型,淡化阶段、养殖阶段和合并2个阶段存活性状转换后的遗传力分别为0.46、0.41和0.53,与0相比,估计值均达到极显著水平(z2.58);基于A+C模型,3个阶段遗传力转换后估计值分别为0.06、0.05和0.07,与0相比,估计值均未达到显著水平(z1.96)。基于A模型和A+C模型,获得的2个阶段间家系存活性状育种值的相关系数分别为0.41±0.09和0.48±0.09。由于半同胞家系比例仅为47%,家系单独在网箱中测试,家系遗传效应与共同环境效应部分混淆,因此,基于A模型获得的遗传力估计值偏高,基于A+C模型获得的遗传力估计值偏低。本研究结果表明,通过多代选择育种,可以改良凡纳滨对虾幼虾淡化和低盐度养殖存活性能。     

电渗析法处理苹果酸废水溶液的研究

生产脱色脱酸苹果汁时,树脂碱洗液中含有大量天然L-苹果酸,研究了采用电渗析法脱盐回收废液中的苹果酸,及其对苹果酸废液脱盐的工艺条件。将废液pH调至4.0,工作电流11A下循环脱盐2 h,脱盐率达99%以上,含Na 11 821 mg/L的废液脱盐至含Na 42.88 mg/L,其中L-苹果酸损失18.94%,基本达到分离要求,表明了电渗析对苹果酸废液的脱盐是切实可行的。     

豆科牧草对滨海盐渍土壤盐分特性和肥力影响的研究

[目的]探讨豆科牧草用于滨海盐渍土生物改良的可性行。[方法]利用田间长期定位试验,研究种植豆科牧草林生山黧豆和紫花苜蓿的人工草地对滨海盐渍土壤盐分特性和肥力的影响。[结果]与自然盐碱空白地相比,长期种植紫花苜蓿和林生山黧豆的人工草地的土壤盐分含量明显降低,0～40 cm土层脱盐最为强烈,脱盐率达47.8%～48.8%,土壤盐分分布由柱状型转变为底积型;0～20 cm土壤pH值明显降低;0～20 cm土层的有机质、全氮含量分别提高了28.4%、42.5%和95.6%、69.8%。紫花苜蓿草地与自然盐碱空白地的盐分离子运移存在着差异。[结论]中度盐渍化土壤种植紫花苜蓿,轻度盐渍化土壤种植林生山黧豆,是生物改良滨海盐渍土的有效途径。     

枯枝碎屑对吹填土的脱盐效果

[目的]研究枯枝碎屑对吹填土脱盐及理化性质的影响。[方法]采用室内土注淋洗模拟脱盐试验,设不添加枯枝碎屑(CK)、添加土柱体积5%的枯枝碎屑、添加土柱体积10%的枯枝碎屑,研究枯枝碎屑的脱盐效果。[结果]添加枯枝碎屑有利于加快吹填土盐峰形成、下移和消失,且随着枯枝碎屑添加量的增加而加快,脱盐碱化特征明显高于CK。[结论]枯枝碎屑可应用于吹填土脱盐。     

Life Cycle Assessment of biomass production in a Mediterranean greenhouse using different water sources: Groundwater, treated wastewater and desalinated seawater

An experimental biomass crop of Nicotiana tabacum was grown over a nine-month period inside a greenhouse situated in Almería, south-eastern Spain. Two irrigation methods corresponding to treated urban wastewater and groundwater, were arranged. No significant differences were observed in the total biomass produced on the treated wastewater and groundwater plots, which ranged from 17 to 28 kg m⁻², depending on plant density. Environmental Life Cycle Assessment (LCA) was applied in order to gain knowledge of the potential impacts of using either treated wastewater, groundwater, or desalinated water for irrigation. The LCA study included all the processes involved in agricultural production up to the final plant cutting. Since desalinated water was not actually used in the experiment, the experimental data from tobacco irrigated with groundwater was used in the LCA. Impact categories included were: global warming; acidification; water eutrophication; primary energy use; as well as aquatic and terrestrial ecotoxicity. Special attention was put on the ecotoxicity of emerging and priority pollutants in treated wastewater, as well as on soil quality impacts, namely soil organic carbon deficit and soil salinisation. The results show that using desalinated water leads to higher environmental impacts in several impact categories, including global warming, energy use, soil quality, and aquatic ecotoxicity. As an example, primary energy use increases by 80% and 50% as compared to using treated wastewater and groundwater, respectively. On the other hand, wastewater pollutants in irrigation water may involve a relevant contribution to terrestrial ecotoxicity. For this reason, the impact score of the wastewater-irrigated crop is 23% and 35% higher as compared to the crop using desalinated water and groundwater, respectively.     

Fish survival in groundwater-desalination concentrate

The number of groundwater brackish water desalination plants has been increasing in recent years. The concentrate streams produced by these plants are an attractive new source of water for aquaculture, but risk fish mortality associated with water composition and CaCO₃ precipitation. In the present work, fish survival in raw and calcium-reduced concentrate has been studied in a nearly closed system. All of the fish survived in all water types during the entire three months experiment. Nitrate, however, rapidly accumulated and mineral precipitates clogged the biofilter. These phenomena may complicate operation for longer duration, especially when high densities are employed.     

浒苔去盐技术研究

[目的]研究浒苔去盐的方法,进一步拓展浒苔的应用范围。[方法]根据浒苔的结构特征,设计合成几种离子液体,对浒苔进行溶解。通过X射线衍射(XRD)和红外光谱(FT-IR)对原始浒苔及溶解后再生的浒苔进行表征,筛选出对浒苔具有良好溶解性能及优良去盐性能的离子液体。[结果]1-丁基-3-甲基咪唑氯盐([Bmim]Cl)离子液体在温度为85~90℃时对浒苔具有优良的去盐性能。去盐过程不影响浒苔本身的结构,并且1-丁基-3-甲基咪唑氯盐离子液体可以重复使用。[结论]离子液体溶解浒苔去盐方法简单有效、环境友好,为浒苔去盐提供一条简便的途径。     

地面覆盖方式对新垦盐碱地的抑盐和增产效果研究

采用塑料地膜、细沙、秸秆3种覆盖材料,研究了不同地面覆盖方式对新垦盐碱荒地的抑盐、脱盐和玉米的增产效果。结果表明,不同覆盖材料和方式均有显著的增产作用,其中全膜覆盖效果最好,其次是覆细沙5cm,覆秸秆3000kg/hm2。的增产率最小。覆盖处理对O～20cm土层的盐分均有很好的脱盐效果,可减弱休闲季土壤0-40cm土层的返盐。秸秆覆盖和细沙覆盖各层的含水量与覆盖量正相关。