激光诱导击穿原子光谱在土壤分析中的应用     

马菲  周健民  杜昌文 《土壤学报》2022,59(3):642-653

土壤分析是土壤学研究及应用的前提和基础,传统化学土壤分析方法逐渐不能适应现代土壤学海量信息数据快速获取的需求。激光诱导击穿光谱作为一种全新的、反映土壤组成元素原子信息的光谱技术,其无需对样品进行复杂前处理,可实现原位、快速、多元素连续在线检测,每条光谱记录土壤样本独一无二的特征,可以视为土壤“指纹”,成为现代土壤分析的有效技术之一。首先介绍和分析了激光诱导击穿原子光谱的原理、光谱获取的主要影响因素、光谱数据处理的化学计量学方法等;然后阐述和梳理了基于激光诱导击穿光谱技术在土壤分析方面的应用成果和进展,包括土壤鉴定、土壤养分评估、土壤重金属测定、微观/介观尺度土壤原位表征等;最后讨论和总结了激光诱导击穿光谱技术在土壤分析中所面临的挑战及其应用展望。  相似文献   

产脂肪酶乳酸菌对新疆传统奶酪脂肪酸及风味的影响     

李宇辉  王俊钢  刘成江  许先猛  李晓楠 《农业工程学报》2022,38(6):319-329

为了改善奶酪品质,奶酪生产过程中通常会添加脂肪酶或者产脂肪酶乳酸菌来提升产品品质。该研究以前期筛选的4株高产脂肪酶乳酸菌为发酵剂,分别随机选取3株乳酸菌复配制作酸凝奶酪。试验组：A组T1-5和T1-3属融合魏斯氏菌（Weissella confusa）、H1-6属瑞士乳杆菌（Lactobacillus helveticus）,B组H1-6、T1-5、B2-5属植物乳杆菌（Lactobacillus plantarum）,C组H1-6、T1-3、B2-5,D组T1-3、T1-5、B2-5,对照组（E组）（添加商业发酵剂）,分析发酵剂对传统奶酪pH值、滴定酸度和脂肪氧化情况的影响,并利用气相色谱法（Gas Chromatography,GC）检测奶酪中脂肪酸变化、利用气相色谱-离子迁移谱（Gas Chromatography-Ion Mobility Chromatography,GC-IMS）分析奶酪中风味物质的变化。结果表明：A,B,C,D组4组奶酪的pH值、过氧化值（Peroxide value,POV值）明显低于E组（对照组）（P < 0.05）,A,B组奶酪滴定酸度比对照E组高（P < 0.05）;A,B,C,D组奶酪中饱和脂肪酸（Saturated Fatty Acids,SFA）含量、单不饱和脂肪酸（Monounsaturated Fatty Acids,MUFA）含量和多不饱和脂肪酸（Polyunsaturated Fatty Acids,PUFA）含量均显著高于E组（P < 0.05）;4个试验组样品中亚油酸（C18∶2n6c）含量明显高于对照组（E组）（P < 0.05）。GC-IMS及主成分分析结果显示,A、B组奶酪挥发性风味物质种类多,且相似度较高,其中2-庚酮、丁醛、乙酸丁酯是主要呈味物质;C、E两组奶酪中风味物质比较相似,风味物质主要以乙酸乙酯、乙酸丙酯、己酸乙酯等酯类为主;D组与其他4组有所差异,主要挥发性风味物质为乙酸丁酯、3-辛酮、庚醛等。结合感官评定,A、B两组奶酪整体风味和口感较好,评分较高。筛选得到的产脂肪酶乳酸菌可以作为发酵剂用于提升新疆传统奶酪品质。  相似文献   

设施大棚间作玉米对丛枝菌根网络形成及辣椒疫病防治的影响     

刘一凡  侯劭炜  胡君利  蔡鹏  李明慧  吴福勇  林先贵 《土壤学报》2022,59(5):1378-1385

丛枝菌根（Arbuscular mycorrhizal,AM）真菌对辣椒疫病等土传病害具有生防潜力,但由于难以纯培养而未能实现规模化生产应用,如能调动土著AM真菌的抑病功能则对实际生产具有重要指导意义。依托重庆石柱辣椒科技园,研究设施大棚中间作玉米对土著AM真菌生长及辣椒疫病防治的影响。结果表明,与辣椒单作相比,间作玉米处理辣椒根系AM真菌侵染率、根际AM真菌数量与土壤磷酸酶活性以及小区作物养分总吸收量均显著提高,辣椒疫病发病率与病情指数、单株辣椒的磷吸收量及果实生物量均显著下降,其中种植密度更高的等垄宽间作处理两种作物根系AM真菌侵染率、小区玉米产量及作物养分总吸收量均显著高于等行距间作处理,辣椒疫病发病率与之正好相反。设施环境下间作玉米或能通过促进AM真菌生长及其对辣椒根系的侵染来增强其对辣椒疫病的防治功效,其中等垄宽间作处理具有更好的经济效益。  相似文献   

Emission of dimethyl sulfide,carbonyl sulfide,and carbon bisulfide from paddy fields     

Ken-ichi Kanda  Haruo Tsuruta  Katsuyuki Minami 《Soil Science and Plant Nutrition》2013,59(4):709-716

Abstract

Emission rates of dimethyl sulficle (DMS), carbonyl sulfide (COS), and carbon disulfide (CS₂) to the atmosphere from paddy fields at Ryugasaki, Ibaraki Prefecture, Japan were measured by using the closed chamber method. DMS was emitted mainly through the rice plant and its emission rate was much higher than those of COS and CS₂. During a cropping period COS was slightly absorbed by the rice plant. Significant diurnal and seasonal variations of DMS iuxes were observed. The highest DMS iux was observed immediately after the heading day of rice plant. The annual DMS emission rate was in the order of mineral plot > straw plot > no-N plot, ranging from 4.5 to 6.9 mg S m^-2 yr^-1. The annual COS emission rate was in the order of straw plot > no-N plot > mineral plot, ranging from -0.2 to 1.8 mg S m^-2 yr^-1. The annual CS₂ emission rate was slightly higher in the straw plot, ranging from 0.9 to 2.0 mg S m^-2 yr^-1.  相似文献   

Density separation of soil organic matter across three land uses in calcareous soils of Iran     

Hanyeh Sepahvand  Reza Mirzaeitalarposhti  Torsten Müller 《Archives of Agronomy and Soil Science》2013,59(13):1820-1830

ABSTRACT

The aim of this study was to examine the usefulness of physical and chemical fractionation in quantifying soil organic matter (SOM) in different stabilized fraction pools. Soil samples from three land use types in Lorestan province, Southwest Iran were examined to account for the amount of organic carbon and nitrogen in different SOM fractions. Size/density separation and chemical oxidation methods were applied to separate the SOM fractions including particulate organic matter (POM), Si + C (silt and clay), DOC (dissolved organic C), rSOM (oxidation-resistant organic carbon and nitrogen) and S + SA (sand and stable aggregates). The values obtained for TOC, TN, and HWC were highest in forest lands followed by the range and agricultural lands. Among the SOM fractions, S + SA showed the highest values (5.75, 5.77 and 20.6 g kg^?1 for agriculture, range and forest lands respectively) followed by POM, Si + C, rSOM, and DOC. The concentrations of C and N in the labile fractions obtained the higher values than in the stabilized fractions. Forest lands had the highest amounts of organic C and N among all fractions whereas agricultural lands showed highest values for inorganic C content of soils in different fractions.  相似文献   

Effects of seedbed properties on crop emergence: 3. Effects of firming of seedbeds with various sowing depths and water contents     

Inge Håkansson  Tomas Rydberg  Thomas Keller 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(8):701-710

Abstract

Extensive experiments were carried out in shallow plastic boxes placed directly on the ground in the field to study the effects of seedbed properties on the emergence of various crops in a cool temperate climate. In a group of experiments with barley (Hordeum vulgare L.), we studied the effects on crop emergence of firming (slight compaction) of the seedbed, simulating the recompacting effects of rolling after sowing or press wheels on the seed coulters. Most of the experiments were carried out without irrigation after sowing. The firming usually had a slightly positive effect on emergence when the water content in the surface layer at sowing was below the wilting point. When the water content in the surface layer was higher, firming often reduced emergence drastically, particularly with deep sowing and in coarse-textured soils. The main reason for negative effects was harmful hardening of the surface layer when the more firm seedbed gradually dried out. When irrigation kept the seedbed continuously moist, the negative effect of firming was almost eliminated. Very high initial water content in the basal layer tended to delay surface layer drying and hardening, and to reduce the negative effect of firming. Firming only slightly influenced the evaporative water losses from the soil. In contrast to the results presented here, previous field trials with cereals have usually resulted in more positive effects of rolling after sowing. This indicates that other effects than firming, such as modification of sowing depth and reshaping of the soil surface, are other important effects of rolling.  相似文献   

黄土高原植被净初级生产力时空变化及其影响因素   总被引：8，自引：3，他引：8  

谢宝妮  秦占飞  王洋  常庆瑞 《农业工程学报》2014,30(11):244-253

为了探明黄土高原地区植被生产力变化的驱动机制,该文基于MODIS传感器获得的MOD17A3数据,分析了黄土高原2000-2010年间植被净初级生产力(net primary productivity,NPP)的时空变化及其主要影响因素,并借助多元统计分析方法对引起NPP变化的自然和人为因素进行量化分析。结果表明:黄土高原植被总NPP从2000年的119 Tg(以C计)增加到2010年的144 Tg(以C计),年增速4.57 g/(m2·a)(P0.05)(以C计)。黄土高原约91%的区域NPP呈增加趋势,37%的区域增加趋势显著,主要分布在陕西、青海大部分地区、甘肃南部及宁南山区。整个黄土高原近11 a间NPP变化受自然和人为因素共同影响,其中退耕还林还草累计面积、帕尔默干旱指数(palmer drought severity index,PDSI)、耕地面积和人口数量是影响NPP变化的主要因素。退耕还林还草累计面积占四者总贡献率的43%,PDSI占40%,耕地面积和人口数量分别占13%和4%。对区域而言,由退耕还林还草工程引起的土地利用覆被变化是退耕区(陕北、甘肃东南部等)NPP增加的主要因素,而近年来干旱情况的缓解(PDSI呈上升趋势)则是青海、内蒙古等地NPP增加的主要因素。该研究对于黄土高原各区域生态资源管理,以及生态系统的建设具有一定的指导和借鉴意义。  相似文献   

基于耕地质量指数局部空间自相关的耕地保护分区   总被引：15，自引：12，他引：15  

韦仕川  熊昌盛  栾乔林  胡月明 《农业工程学报》2014,30(18):249-256

科学合理地制定耕地保护分区,是实现耕地差异化保护、精细化管理的重要保障。该文采用Moran散点图和局部空间自相关分析相结合的方法,以耕地质量指数为空间变量,探讨广宁县耕地质量的空间结构性特征和聚集性规律,并据此提出耕地保护分区方案。研究结果表明:广宁县耕地质量在空间分布上呈现出一定的聚集性规律,正相关类型(高-高和低-低型)多以"组团"形式出现,聚集性较强;负相关类型(高-低和低-高型)无明显集中区域,零星分布。基于局部空间自相关分析的耕地保护分区,既综合考虑了耕地自然条件、利用条件和经济条件,同时将耕地质量的空间属性作为第4维,纳入到耕地保护分区研究中,为耕地差异化保护、精细化管理提供了思路。最后,提出了基于局部空间自相关的耕地保护分区方案及相应的保护措施,可为研究区域耕地保护分区提供参考。  相似文献   

看麦娘叶片对化感小麦根水提液的生理响应     

邱秋金  李圆萍  王微  陈珊  肖清铁  郑新宇  王经源  林瑞余  林文雄 《中国生态农业学报》2014,22(11):1357-1363

为阐明小麦化感抑草的生理机制,选择强化感小麦‘115/青海麦’、‘92L89’和弱化感小麦‘抗10103’,通过添加浓度为0.2%、0.5%和1.0%的小麦根水提液进行水培试验3周后,测定了各处理看麦娘的鲜重,分析叶片中叶绿素(SPAD值)、可溶蛋白、MDA、类黄酮、总酚的含量以及SOD、POD、CAT活性。结果表明,水提液处理显著抑制了看麦娘的生长,抑制率在不同处理浓度及小麦品种间均存在显著差异,强化感小麦的抑制率显著高于弱化感小麦。在处理浓度范围内,不同小麦根水提液的抑制率大小依次为‘115/青海麦’(24.7%~74.3%)‘92L89’(15.7%~71.6%)‘抗10103’(13.8%~61.4%);0.2%、1.0%和5.0%水提液处理的抑制率大小依次为13.8%~24.7%、41.7%~66.4%和61.4%~74.2%。看麦娘叶绿素含量(SPAD值)随处理浓度增大显著降低,可溶蛋白含量,SOD、POD、CAT活性,MDA、类黄酮含量随处理浓度增大显著升高,强化感小麦对看麦娘的生理刺激作用高于弱化感小麦。1.0%‘115/青海麦’及5.0%各小麦水提液处理的看麦娘总酚含量高于对照。可见,小麦化感胁迫提高了看麦娘的保护酶系统活性,增强了抗氧化物质代谢,但显著增强了细胞膜脂质过氧化和叶绿素降解,不利于靶标植物看麦娘的生长。  相似文献   

大兴安岭天然林不同林分溶解有机碳变化特征   总被引：1，自引：0，他引：1  

杜浩  张成福  程宇琪  王雨晴  潘思涵  杨宇娜 《水土保持研究》2019,26(6):46-52

为确定不同林分和季节变化对森林碳库影响。在内蒙古大兴安岭根河林业局境内选取具有代表性的林分,即白桦林、白桦落叶松混交林以及落叶松林为研究对象。收集并测定了树干径流、有机质层和0-30 cm土层中DOC浓度,并分析了DOC变化特征以及不同月份对DOC的影响。结果表明:不同林分中树干径流中DOC平均浓度分别为60.12,172.77,205.02 mg/L;有机质层中DOC平均浓度分别为35.32,39.64,34.45 mg/L;0-30 cm土层中DOC平均浓度分别为26.23,37.08,26.53 mg/L。结果表明:不同林分中DOC浓度表现为树干径流 > 有机质层 > 0-30 cm土层,落叶松林树干径流DOC浓度明显高于白桦林（p<0.05）,且落叶松树干比白桦树干淋溶DOC强;不同林分中有机质层和0-30 cm土层表现为白桦落叶松混交林>白桦林、落叶松林,但无明显的差异（p>0.05）,而且有机质层和土层对DOC有吸附固定作用;不同林分6-9月份树干径流中DOC浓度呈现先升高后降低的趋势,7月份达到最大,机质层和0-30 cm土层中DOC浓度6月份最高,7月、8月最低,而9月份又升高。不同林分和月份的变化,影响了天然林中DOC浓度分布。  相似文献