养殖专用紫外光源辐照试验研究

家禽是在自然环境下进化而来,转为室内圈养,必然得不到充足的阳光,因而造成严重缺光,其中最缺的光谱波段是太阳投射到地面的紫外线。针对上述问题,本研究首先设计研制了养殖专用紫外光源,以专门弥补阳光中所含对家禽机体最有生物作用的中长波紫外线,进而对部分圈养家禽进行了紫外辐照试验研究。     

SUSTAINABLE NUTRIENT MANAGEMENT PACKAGE FOR COST-EFFECTIVE BIOENERGY BIOMASS PRODUCTION

Commercial fertilizer (particularly nitrogen) costs account for a substantial portion of the total production costs of cellulosic biomass and can be a major obstacle to biofuel production. In a series of greenhouse studies, we evaluated the feasibility of co-applying Gibberellins (GA) and reduced nitrogen (N) rates to produce a bioenergy crop less expensively. In a preliminary study, we determined the minimum combined application rates of GA and N required for efficient biomass (sweet sorghum, Sorghum bicolor) production. Co-application of 75 kg ha^?1 (one-half of the recommended N rate for sorghum) and a modest GA rate of 3 g ha^?1 optimized dry matter yield (DMY) and N and phosphorus (P) uptake efficiencies, resulting in a reduction of N and P leaching. Organic nutrient sources such as manures and biosolids can be substituted for commercial N fertilizers (and incidentally supply P) to further reduce the cost of nutrient supply for biomass production. Based on the results of the preliminary study, we conducted a second greenhouse study using sweet sorghum as a test bioenergy crop. We co-applied organic sources of N (manure and biosolids) at 75 and 150 kg PAN ha^?1 (representing 50 and 100% N rate respectively) with 3 g GA ha^?1. In each batch of experiment, the crop was grown for 8 wk on Immokalee fine sand of minimal native fertility. After harvest, sufficient water was applied to soil in each pot to yield ～1.5 L (～0.75 pore volume) of leachate, and analyzed for total N and soluble reactive P (SRP). The reduced (50%) N application rate, together with GA, optimized biomass production. Application of GA at 3 g ha^?1, and the organic sources of N at 50% of the recommended N rate, decreased nutrient cost of producing the bioenergy biomass by ～$375 ha^?1 (>90% of total nutrient cost), and could reduce offsite N and P losses from vulnerable soils.     

秸秆生物质炭对稻田土壤剖面N2O和N2浓度的影响*

氧化亚氮（N2O）和氮气（N2）是淹水稻田土壤剖面反硝化过程的重要气态产物,可通过土水界面向大气排放,也可随水向下淋溶。秸秆生物质炭施入稻田后会改变土壤理化及微生物学性质,影响反硝化过程及N2O和N2产排。本研究依托2010年夏建立的连续秸秆生物质炭还田的稻麦轮作农田试验,通过埋设淋溶管收集土壤剖面溶液,采用气相色谱和膜进样质谱分别定量溶液中N2O和exN2（反硝化产生N2量）,观测了2018和2019年水稻季不同秸秆生物质炭施用量（CK：每季0 t·hm-2;1BC：每季2.25 t·hm-2;5BC：每季11.3 t·hm-2;10BC：每季22.5 t·hm-2）下0~1 m土壤剖面溶液中N2O和exN2浓度的时空变化,评估了长期施用秸秆生物质炭对稻田土壤剖面反硝化作用及其主要气态氮产物exN2随水流失的影响。结果表明,两个稻季CK处理N2O浓度以60 cm处较高,exN2浓度则随土壤深度增加呈降低趋势。秸秆生物质炭处理能降低剖面N2O和exN2浓度,以10BC处理最为明显。其中,N2O浓度降低以60 cm处较大,exN2浓度降低随土壤深度增加而加大。施用秸秆生物质炭对土壤剖面溶液无机氮（NO3-+NH4+）含量无明显影响,但5BC和10BC处理增加了可溶性有机碳（DOC）和溶解氧（DO）浓度以及氧化还原电位（Eh）。CK处理下土壤剖面溶液N2O和exN2浓度变化与DOC、硝态氮（NO3-）及DO有关;秸秆生物质炭处理下则主要受DO和Eh控制。exN2淋溶量（按1 m深度计算）CK处理下为2.3 ~5.5 kg·hm-2,相当于无机氮和有机氮（DON）淋溶量的32%~34%,5BC和10BC处理则降低为1.7 ~3.7 kg·hm-2和1.1~1.9 kg·hm-2,上述结果表明,反硝化产生N2随水淋溶量不容忽视,秸秆生物质炭还田可改善淹水稻田土壤剖面的通气状况,增加DO,提高Eh,进而有效减少深层反硝化及其主要气态产物exN2随水流失的风险。     

饲料用秸秆丝化多频快速压缩成型工艺参数优化

为了进一步探明丝化后干玉米秸秆压缩成型的最佳工艺参数,利用WDW-200微机控制电子式万能试验机,以秸秆含水率、最大压缩力(能够压缩成型的最小压缩力)、压缩次数和压缩速度为影响因子,对饲料用玉米秸秆丝化后压缩成型块的松弛比进行了二次回归旋转组合试验研究。建立并分析了4个影响因子对玉米秸秆丝化压缩成型松弛比的回归模型,并进行了验证试验。结果表明:丝化后玉米秸秆压缩成型最佳工艺条件为:含水率为7.8%~18.3%,能够成型的最小压缩力为6.22 MPa,压缩次数为2~6次,压缩速度为128~337 mm/min。在此工艺条件下,干玉米秸秆丝化压缩成型的松弛比在1.2和1.5之间,均能满足实际生产中较低能耗与生产质量的要求。该试验对压缩工艺的优化、压缩设备的研制和了解压缩成型后产品的特性具有参考意义。     

木薯收获机土薯抖动分离装置性能仿真及试验

为了考察木薯收获机块根拔起时弹簧式土薯抖动分离装置的土薯分离机理和因素对分离性能的影响规律,优化性能影响因素,进行弹簧式土薯抖动分离装置动力学仿真试验.采用光滑粒子流体动力学和有限元的耦合方法及二次回归通用旋转设计方法,构建土壤-木薯-抖动分离装置系统的动力学仿真模型和影响土薯分离性能的回归数学模型,研究了木薯块根拔起时土薯抖动的分离机理及各影响因素对土薯分离性能的影响规律,同时,采用MATLAB优化工具箱中的fmincon函数,对性能影响因素进行了优化.结果表明,因素的优组合为:长孔长度2.68 cm、弹簧刚度20.04 kN/cm、弹簧预紧力335.2 N,相应的干净度为0.778,碰撞力为320 N,试验验证的干净度为0.698,与理论结果的相对误差较小,约为10％,理论结果与验证结果较一致,表明建立的回归数学模型及优化结果合理.研究结果可为土薯分离质量高的挖拔式木薯收获机弹簧式土薯抖动分离装置的设计提供参考.     

浙北平原不同种植年限蔬菜地土壤氮磷的积累及环境风险评价

长期过量施肥可导致蔬菜地土壤养分大量累积、养分利用效率下降和环境污染风险增加。以浙北平原不同种植年限蔬菜地土壤为研究对象,采用化学测试方法研究了菜地土壤氮和磷的积累及其淋失潜力的变化。结果表明,随着种植年限的增加,蔬菜地土壤全磷、有效磷（Olsen P）和NO3-N呈明显的积累;蔬菜种植年限为〈2、2～5、6～10、11～20、20～30和＆gt;30a的表土全P平均分别为0.66、0.75、1.07、1.49、2.40和2.12g·kg-1,有效P平均分别为13.2、37.8、42.2、70.2、137.9和101.7mg·kg-1,NO3-N平均分别为9.15、13.58、50.18、46.48、73.28和74.20mg·kg-1,同时土壤N和P垂直下移渐趋明显。土壤水溶性磷含量随土壤有效磷（OlsenP）积累的变化存在一个明显的突变点,相对应的土壤OlsenP临界值约为60mg·kg-1。随着种植年限增长,蔬菜地地表径流中氮和磷浓度呈明显增加,利用年限为20～30a的蔬菜地径流中可溶性P和NO3-N浓度分别约为利用年限〈2a蔬菜地的13.12和9.48倍。研究认为,长期超量施肥已导致这一地区蔬菜地土壤养分的过度积累,在蔬菜生产中应重视和提倡平衡施肥,控制土壤氮磷的积累。     

Nutrient leaching from the plow layer by water percolation and accumulation in the subsoil in an irrigated paddy field

To estimate the impact of water percolation on the nutrient status in paddy fields, the seasonal variations of the concentrations of cations, anions, inorganic carbon (IC), and of dissolved organic carbon (DOC) in percolating water that was collected from just below the plow layer (PW-13) and from drainage pipes at the 40 em depth (PW-40), as well as in irrigation water were measured in an irrigated paddy field. Total amounts of Ca, Mg, K, Fe, and Mn leached from PW-13 during the period of rice cultivation were estimated to range from about 390 to 770, 65 to 130, 33 to 66, 340 to 680, and 44 to 87 kg ha^-1, respectively. Amounts of losses that were estimated from the differences between the input by irrigation water and the output by percolation water from the plow layer corresponded to 11 to 26, 22 to 47,5.9 to 12, and 13 to 26% of exchangeable Ca and Mg, amorphous Fe, and easily reducible Mn in the plow layer, respectively. The concentrations of Ca, Mg, K, Fe, and Mn in PW13 were higher than those in PW-40. The amounts of these nutrients that were retained in the subsoil between the 13 em and 40 em soil depth corresponded to 83, 86, 61, 99, and 89% of the amounts that percolated from the plow layer, respectively. Total amounts of IC and DOC that percolated from the plow layer ranged from 750 to 1,500 and 85 to 170 kg-C ha^-1, which corresponded to 5.0 to 10.0% and 0.6 to 1.1% of the total carbon content in the plow layer, respectively. Eighty eight % of IC in the percolating water from the plow layer was also retained in the subsoil.     

Occurrence of Polycyclic Musks in Sewage Sludge and their Behaviour in Soils and Plants. Part 1: Behaviour of Polycyclic Musks in Sewage Sludge of Different Treatment Plants in Summer and Winter (5 pp)

Background, Aim and Scope   Part 1: Behaviour of Polycyclic Musks in Sewage Sludge of Different Treatment Plants in Summer and Winter Part 2: Investigation of Polycyclic Musks in Soils and Plants -  Preamble. In Part 1 of the study, screening tests were performed to investigate the occurrence of PCMs in sewage sludges. For a preliminary risk assessment, further information is needed about their behaviour in the terrestrial environment. Hence, Part 2 examined the adsorption of PCMs to soil, their dissipation and leaching in soil and their uptake by plants. Background, Aim and Scope   Polycyclic Musks (PCMs) enter the environment via the waste water system. Because of their persistence, they can accumulate in different matrices like sewage sludge or biota. By the use of sewage sludge as a fertilizer, PCMs are transferred to agricultural soils. Therefore, in Part 1 of the study, screening tests were performed to investigate the occurrence of PCMs in sewage sludge. For a preliminary risk assessment, further information is needed about their behaviour in the terrestrial environment. Hence, Part 2 of the study examined the adsorption of PCMs to soil, their dissipation and leaching in soil, and their uptake by plants. Materials and Methods: In the screening study, samples of activated sewage sludge were taken both in summer and in winter at 21 treatment plants. In order to get an overview of the contamination situation, sampling covered different types of treatment plants (in rural, urban, industrial areas). Analytical methods for the determination of HHCB, AHTN, ADBI, ATTN, AHDI and ATII in the sludge samples were developed and applied. Results: The analytical screening of PCMs showed their presence in activated and dried sewage sludge samples. HHCB and AHTN represented about 95% of the PCMs investigated. Their concentrations in the activated sludge samples varied between 2.9 and 10.4 mg/kg dry mass (dm) and 1.1 to 4.2 mg/kg dm, respectively. Although different types of sewage treatment plants were investigated, similar PCM levels were found, showing the widespread input of these compounds into domestic waste water. Discussion: PCM concentrations in activated sludge varied widely. The variation drops substantially when concentrations are related to the varying dry mass. In dehydrated sludge, PCM concentrations were up to 24 mg/kg dm for HHCB and up to 6.9 mg/kg dm for AHTN. These high values are comparable to those obtained in other investigations analysing PCMs. If the degradation of organic mass during anaerobic decomposition is included in the evaluation, the figures obtained are comparable to those for activated sludge. Elimination in sewage sludge was higher in summer than in winter. Therefore, the contamination of the sludges in winter reached higher levels compared to the summer. Conclusions: The results show that PCMs are widespread contaminants in sewage sludge. Recommendations and Perspectives: PCM should be considered in a risk assessment as potential contaminants of sewage sludge destined for agricultural use. Due to the high PCM levels in sewage sludge, further investigations into the degradation and elimination behaviour in sewage sludge have to be carried out, including that involving PCM metabolites such as lactone derivatives.     

28株牛源分枝杆菌的耐药基因突变分析

为明确分离自宁夏、甘肃和新疆地区的28株牛源分枝杆菌的耐药基因突变情况,通过采用16S rRNA、MPT64和多位点PCR方法进行基因分型鉴定,L-J比例法对其进行药敏试验,随后用DNA测序技术对10株耐药菌和4株敏感菌进行耐药基因检测及突变分析。分型鉴定结果表明,28株分离株均属于结核分枝杆菌复合群(MTBC),其中26株为牛分枝杆菌,2株为人型结核分枝杆菌。药敏试验结果表明,28株MTBC中18株对4种一线抗结核药物敏感,10株耐药。耐药菌株中,1株对利福平耐药;7株对异烟肼、利福平和链霉素三重耐药;2株对异烟肼、利福平、链霉素和乙胺丁醇四重耐药。耐药基因突变位点分析结果表明,rpoB 378位点的突变率为10.0%;katG 463位点的突变率为100.0%;rrs 311位点的突变率为11.1%;embB 378位点的突变率为100.0%;oxyR-ahpC和rpsL位点无突变。提示宁夏、甘肃和新疆地区奶牛场中MTBC主要以牛分枝杆菌为主,且存在耐多药情况,耐药突变位点以katG 463和embB 378为主。     

基于SPEI的宁夏沿黄城市带干旱特征及驱动性分析

宁夏沿黄城市带气候变化敏感,生态环境脆弱,探究区域干旱驱动机制,对进一步研究黄河流域高质量发展,优化区域农业水资源管理具有重要意义。利用研究区1995—2015年的气象资料,采用彭曼蒙特斯模型(P-M模型)和标准降雨蒸散指数(SPEI)获得区域潜在蒸散发量和干旱指数,通过Mann-Kendall突变检测法、滑动t检验和Pettitt突变检验,分析了研究区干旱时间变化周期,利用冗余分析法定量分析宁夏沿黄城市带干旱驱动因素。结果表明：(1)研究区在季节尺度上,单季旱发生频繁,以春季和秋季发生为主,自北向南整体呈现由高到底的趋势,且主要发生在北部地区,整体以0.013/10 a速率呈湿润化趋势;(2)在年尺度上干旱的下降趋势具有全域性,自北向南呈现由高到底的趋势;(3)宁夏沿黄城市带SPEI-12值在研究时段呈现逐年下降的趋势,通过3种突变检测函数,确定2008年出现异常值,这与降水分布一致;(4)各环境因子对SPEI指数的解释率均在75%以上,降水量、温度、地表净辐射是驱动SPEI值主要环境因子。其中,降水量对SPEI的贡献率最高,呈显著正相关关系。