Estimating nitrogen status of rice using the image segmentation of G-R thresholding method
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2015年2月 CIESC Journal ·723·February 2015第66卷 第2期 化 工 学 报 V ol.66 No.2厌氧发酵制备生物燃气过程的物质与能量转化效率牛红志1,2,孔晓英1,李连华1,孙永明1,袁振宏1,王瑶1,2,周贤友1,2(1中国科学院广州能源研究所,中国科学院可再生能源重点实验室,广东 广州 510640;2中国科学院大学,北京 100049)摘要:以稻壳为原料,采用批式中温(35℃±1℃)厌氧发酵工艺研究了稻壳厌氧发酵制备生物燃气的产气性能,在此基础上结合物质流分析方法分析了发酵过程中C 、N 元素的分布情况以及物质与能量的转化效率。
研究结果表明稻壳厌氧发酵制备生物燃气过程的产气率和产CH 4率分别为297.41和164.40 ml ·(gVS RH )−1,平均CH 4含量为55.28%;C 元素流向分布:30.7%生物燃气,6.4%沼液,62.9%沼渣;N 元素在剩余物中的流向分布:63.2%沼液,36.8%沼渣;稻壳厌氧发酵制备生物燃气的物质转化效率和能量转化效率分别为30.0%和33.7%。
本研究为农业加工废弃物的资源管理和能源化利用提供了理论依据。
关键词:稻壳;厌氧;发酵;生物燃气产量;甲烷;物质流分析;物质与能量转化效率 DOI :10. 11949/j.issn.0438-1157.20141066中图分类号:X 712 文献标志码:A 文章编号:0438—1157(2015)02—0723—07Material and energy conversion efficiency of biogas preparation process byanaerobic fermentationNIU Hongzhi 1,2, KONG Xiaoying 1, LI Lianhua 1, SUN Yongming 1, YUAN Zhenhong 1,WANG Yao 1,2, ZHOU Xianyou 1,2(1Guangzhou Institute of Energy Conversion , Key Laboratory of Renewable Energy , Chinese Academy of Sciences , Guangzhou510640, Guangdong , China ; 2UCAS , Beijing 100049, China )Abstract: The yield of biogas produced by mid-temperature (35℃±1℃) anaerobic fermentation of rice hulls was investigated, and material and energy flows as well as the distribution of element C and N during this fermentation process were also analyzed using the material flow analysis (MFA) method in this paper. The results showed that during the fermenting rice hulls to prepare biogas, the production rates for biogas and for CH 4 were 297.41 and 164.40 ml ·(gVS RH )−1, respectively; implying that average CH 4 content in biogas was 55.28%, corresponding to 31.16% of the theoretical yield. Based on MFA for the fermentation process system, 30.8% and 6.4% of C element were converted into biogas and slurry, and 62.9% left in residue, separately; 63.2% of N element were converted into slurry and 36.8% left in residue, while negligible N element was in biogas. The efficiencies of material and energy for conversion of rice hulls to biogas were 30.0% and 33.7%, respectively. This study could be as a theoretical basis for resource management and energy utilization of agricultural wastes.Key words: rice hulls; anaerobic; fermentation; biogas yield; methane; material flow analysis; material and energy conversion efficiency2014-07-15收到初稿,2014-08-18收到修改稿。
作物学报ACTA AGRONOMICA SINICA 2020, 46(6): 950 959 / ISSN 0496-3490; CN 11-1809/S; CODEN TSHPA9E-mail: zwxb301@DOI: 10.3724/SP.J.1006.2020.94121品种和生育时期对冠层光谱指数(NDVI)估测马铃薯植株氮素浓度的影响杨海波张加康杨柳贾禹泽刘楠李斐*内蒙古农业大学草原与资源环境学院 / 内蒙古自治区土壤质量与养分资源重点实验室, 内蒙古呼和浩特 010018摘要: NDVI是反映作物叶绿素相对含量及氮素水平的重要参数, 但是作物品种和生育时期的变化对NDVI估测氮素营养的能力有重要影响。
本研究在内蒙古阴山北麓马铃薯主产区进行了多年多品种田间试验, 于2014—2016年7月上旬至8月中旬马铃薯关键生育时期, 利用便携式主动作物传感器GreenSeeker获取马铃薯冠层光谱指数NDVI,对比了品种和生育时期对NDVI估测结果的影响。
结果表明, 块茎形成期NDVI与马铃薯植株氮素浓度相关性较差,随着生育时期的推进, NDVI与植株氮素浓度的线性相关性增强, 块茎膨大期与淀粉积累期组合会显著提高NDVI与植株氮素浓度的线性建模效果。
品种混合会降低NDVI的灵敏性, 增加数据的离散性, 基于时间序列归一化的光谱指数TNDVI能够克服这些问题, 尤其是在块茎膨大期TNDVI与植株氮素浓度的拟合决定系数(R2)能够由原来的0.13提高到0.47。
TNDVI对块茎形成期、块茎膨大期和淀粉积累期组合的线性估测建模R2为0.76, 显著高于NDVI。
株型展开型的品种在块茎膨大期和淀粉积累期更具线性拟合趋势。
研究表明, 马铃薯生育时期和品种对NDVI估测植株氮素浓度有显著影响, 且生育时期的影响更大。
构建的TNDVI光谱指数能够克服品种差异导致的块茎膨大期、淀粉积累期数据分异及饱和现象, 为NDVI在马铃薯植株氮素浓度诊断应用的普适性上提供了理论依据与方法。
·547·大米高转化糖浆制备及理化特性分析罗晶,李信,欧阳玲花,周巾英,袁林峰,胡帅,祝水兰*(江西省农业科学院农产品加工研究所,江西南昌330200)摘要:【目的】研究大米糖浆的制备工艺,并对其理化性质进行分析,为制备高品质大米淀粉糖浆产品提供技术参考。
【方法】以双螺杆挤压酶解处理的抗性淀粉大米碎米粉为原料,采用单因素和正交试验相结合的方法,以葡萄糖值(DE 值)为考察指标,确定复合酶水解制备大米糖浆的最适方案,并通过流变仪、色差仪及高效液相色谱法等测定大米糖浆的理化性质。
【结果】大米糖浆制备工艺条件为:糖化时间4h 、糖化温度60℃、pH 4.0、普鲁兰酶添加量0.10%、β-淀粉酶添加量0.10%、葡萄糖淀粉酶添加量0.25%,DE 值为91.3%,属于高转化糖浆(DE 值>60%);通过对3种酶的正交试验,得出影响酶解主次因素为β-淀粉酶添加量>普鲁兰酶添加量>葡萄糖淀粉酶添加量。
大米糖浆具有糖类的红外特征吸收峰,其糖组分以葡萄糖和麦芽糖为主,含量分别为48.30%和14.38%;色差值(ΔE )为5.33,说明挤压酶解大米糖浆色泽好,透明度高。
【结论】通过双螺杆挤压酶解预处理与酶法水解结合制备的大米糖浆品质好,色泽透明,口感更细腻柔和,可作为首选甜味剂添到各类食品中。
关键词:抗性淀粉大米;碎米;高转化糖浆;挤压酶解;理化特性中图分类号:S511.209.2文献标志码:A文章编号:2095-1191(2023)02-0547-08收稿日期:2022-05-25基金项目:江西省科技支撑计划重点项目(20192BBFL60026,20202BBFL63032);江西现代农业科研协同创新专项(JXXTCX202003,JXXTCXQN202215)通讯作者:祝水兰(1975-),https:///0000-0003-0095-1802,副研究员,主要从事粮油加工贮藏与装备研究工作,E-mail :zhu-*****************第一作者:罗晶(1993-),https:///0000-0001-8484-9420,主要从事粮油加工贮藏与装备研究工作,E-mail :******************Preparation and physical and chemical characteristics of ricehighly transformed syrupLUO Jing ,LI Xin ,OUYANG Ling-hua ,ZHOU Jin-ying ,YUAN Lin-feng ,HU Shuai ,ZHU Shui-lan*(Institute of Agricultural Processing ,Jiangxi Academy of Agricultural Sciences ,Nanchang ,Jiangxi 330200,China )Abstract :【Objective 】The preparation process of rice syrup was studied ,and its physical and chemical propertieswere analyzed to provide technical reference for the preparation of high-quality rice starch syrup products.【Method 】Using resistant crushed rice flour treated by double screw extrusion enzymatic pretreatment as raw material ,the optimal scheme for preparing rice syrup was determined by using the combination of univariate and orthogonal test and the DE value as the investigation index ,and the physical and chemical properties of rice syrup were determined by rheometer ,color difference meter and high performance liquid chromatography.【Result 】The optimal process conditions for rice syrup pre-paration were :saccharification time of 4h ,saccharification temperature 60℃,pH 4.0,Pullulanase additive 0.10%,beta-amylase additive 0.10%,glucose amylase 0.25%,and DE value was 91.3%,belonged to high conversion syrup (DE value>60%).Through orthogonal test of the three enzymes ,the main factor was beta-amylase additive>Pullulanase addi-tive>glucose amylase addition.Rice syrup had the infrared characteristic absorption peak of sugar ,and its sugar compo-nents were mainly glucose and maltose ,accounting for 48.30%and 14.38%of the total sugar ,respectively.Chromatism value (△E )was 5.33,indicating that the extrusion enzyme solution of rice syrup had good color and high transparency.【Conclusion 】The syrup prepared by double screw extrusion enzymatic pretreatment and enzymatic hydrolysis has good quality ,high transparency and more delicate and soft taste ,which can be added to various foods as the preferred sweetener.Key words :resistant starch rice ;crushed rice ;high conversion syrup ;extrusion enzymatic hydrolysis ;physical and chemical characteristicsFoundation items :Jiangxi Science and Technology Support Plan Project (20192BBFL60026,20202BBFL63032);Jiangxi Modern Agricultural Research Collaborative Innovation Project (JXXTCX202003,JXXTCXQN202215)54卷南方农业学报·548·0引言【研究意义】抗性淀粉大米是一种功能稻米,具有饱腹感,可控制饭后血糖值。
第41卷 第3期 生 态 科 学 41(3): 117–1232022年5月 Ecological Science May 2022收稿日期: 2020-04-11; 修订日期: 2020-07-08基金项目: 江西省博士后科研择优资助项目(2015KY42); 国家自然科学基金(31360108)作者简介: 杨文亭(1984—), 男, 助理研究员, 主要从事作物碳氮高效利用研究,E-mail:***************.cn杨文亭, 俞霞, 龙昌智, 等. 氮肥种类和油菜秆还田对水稻苗期碳氮累积的影响[J]. 生态科学, 2022, 41(3): 117–123.YANG Wenting, YU Xia, LONG Changzhi, et al. Effect of nitrogen fertilizer types and canola straw returning on carbon and nitrogen accumulation in rice seedlings[J]. Ecological Science, 2022, 41(3): 117–123.氮肥种类和油菜秆还田对水稻苗期碳氮累积的影响杨文亭1, 2, 俞霞1, 2, 龙昌智1, 朱树伟1, 鲁美娟3, 黄国勤1, 2, *1. 江西农业大学作物生理生态与遗传育种教育部重点实验室, 南昌3300452. 江西农业大学生态科学研究中心, 南昌3300453. 江西农业大学国土资源与环境学院, 南昌 330045【摘要】为探讨不同氮肥种类和油菜秆还田对水稻苗期碳氮累积的影响, 设置了氮肥种类(尿素、碳酸氢铵和硫酸铵)和秸秆还田的双因素的盆栽试验, 测定了移栽后水稻苗期碳氮累积量和碳氮比。
结果表明, 相比施用尿素, 硫酸铵显著提高了水稻地上部氮素累积量, 显著降低了不添加油菜秸秆条件下的水稻地上部和根碳氮比。
添加油菜秆条件下, 施用硫酸铵较尿素显著提高了播后57 d 时水稻地上部和根部碳素累积量。
氮高效水稻品种筛选技术规范1 范围本标准规定了氮高效水稻品种筛选方法的术语和定义、品种选用、氮肥设置、水稻栽培管理及收获、观察记录、生理指标测定和判定指标等。
本标准适用于全国范围内的氮高效水稻品种的筛选。
2 规范性引用文件下列文件中的内容通过文中的规范性引用而构成本文件必不可少的条款。
其中,注日期的引用文件,仅该日期对应的版本适用于本文件;不注日期的引用文件,其最新版本(包括所有的修改单)适用于本文件。
GB 4404.1 粮食作物种子禾谷类NY/T 1105 肥料合理使用准则氮肥NY/T 2017-2011 植物中氮、磷、钾的测定DB33∕T 2517-2022 水稻产量测定操作规范3 术语和定义下列术语和定义适用于本文件。
3.1氮胁迫响应系数Nitrogen coercion response coefficientRIN m,低氮胁迫下水稻某农艺指标相对正常氮肥条件下的变化率。
3.2水稻耐低氮产量评价指数Yield Evaluation Index of Rice Tolerance to Low NitrogenRIC Y,水稻齐穗期粒叶比、成熟期产量及产量构成因素对低氮的响应。
3.3水稻耐低氮分蘖数动态评价指数Dynamic evaluation index of rice dynamic evaluation indexRIC T,水稻分蘖期分蘖动态对低氮的响应。
3.4水稻耐低氮缓苗返青评价指数Rice low -nitrogen -resistant seedlings return green evaluation index RIC R,水稻移栽后缓苗返青对低氮的响应。
3.5水稻转色动态评价指数Dynamic evaluation index of rice color changeRIC C,水稻分蘖期至成熟期水稻顶3叶叶片转色对低氮的响应。
3.6水稻耐低氮氮高效综合指数Composite index of high efficiency of rice tolerance to low nitrogen and nitrogenRIC CM,利用多级指标计算后的指标,用于评价水稻是否氮高效的最终评价指标。
沈阳农业大学学报袁2016 袁47(6):703-710 http:// Journal of Shenyang Agricultural University___________________________________________D01:10.3969/j.1ssn.1000~1700.2016.06.010李英豪,吴奇,陈涛涛,等.沸石氮肥管理对水稻产量及稻米品质的影响[J].沈阳农业大学学报,2016,47(6):703-710.沸石氮肥管理对水稻产量及稻米品质的影响李英豪\吴奇\陈涛涛\孙一迪\迟道才 '金冶2袁孙德环2(1.沈阳农业大学水利学院,沈阳110161曰2.东港市水利局,辽宁东港118300)摘要:为了探求沸石在水稻生产中的价值,于2015年在辽宁省东港市灌溉新技术试验站设置大田试验,研究不同沸石和氮肥量 对水稻产量和稻米品质的影响。
采用裂区试验设计的方法,以氮肥(N)为主区,设置4水平,分别为N i(0kg*hm-2)、N2(52.5kg*hm-2)、队(105kg•hm-2)、N4( 157.5kg• hm-2);斜发沸石(Z)为子区,设置3水平,分别为Z n(0t.hm-2)、Z*( 10窑hm-2 粒径40 目)尧Z S0( 10窑hm-2 粒 径80目冤。
结果表明:在队和当地施氮水平N4下,沸石能显著提髙水稻产量,N3Z40较N3Z。
提髙水稻产量10.5%;NZ4。
较N4Z。
提髙 水稻产量14.5%,N i、N2时沸石对水稻产量影响不显著,沸石粒径对水稻产量无显著影响。
施氮量在52.5~157.5kg*hm-2内,Z«较Z。
平均增加氮肥农艺利用率29.47%,Z S。
较Z。
平均增加氮肥农艺率22.9%。
施用氮肥能够显著降低稻米垩白粒率和垩白度,施人沸石 同样能显著降低稻米垩白粒率,说明氮肥和沸石都能改善稻米外观品质,沸石粒径对稻米外观品质的影响不显著。
热带作物学报2022, 43(2): 321 327Chinese Journal of Tropical Crops不同月份播种对红壤甘蔗干物质与养分积累的影响韦剑锋1,2,韦冬萍1*,胡桂娟1,吴炫柯3,罗小芬2,赵晓玉1,廖文琴1,张灵11. 柳州工学院,广西柳州 545616;2. 广西科技大学,广西柳州 545006;3. 柳州市农业气象试验站,广西柳州 545003摘要:甘蔗是广西重要的经济作物。
为促进甘蔗高效生产,以甘蔗品种‘桂糖42号’为材料,在田间条件下,依据广西甘蔗主要播种月份,设置2月15日、3月15日、4月15日及5月15日4个播种期,分析新植蔗和宿根蔗干物质积累、养分积累及养分经济效率。
结果表明,随播期推迟,新植蔗各器官干物质积累量减少;宿根蔗根、叶干物质积累量增加,茎干物质积累量以3月15日播种最高;两季甘蔗茎干物质积累量为51.88~66.43 t/hm2,其中2月15日、3月15日播种较高,5月15日播种最低;新植蔗根、茎的氮、磷及钾积累量,以及氮、磷及钾积累总量减少,叶的氮、磷及钾积累量增加;宿根蔗各器官氮、磷及钾积累量以5月15日播种最高,2月15日播种最低;两季甘蔗氮、磷及钾积累总量分别为327.17~375.54、37.48~43.82、427.51~503.01 kg/hm2,均以3月15日播种最高,5月15日播种最低。
播种期影响甘蔗干物质与养分分配利用,早播种促进新植蔗干物质和养分向茎分配,提高养分经济效率。
可见,甘蔗早播种的生物产量与养分吸收量较高,而5月15日播种的生物产量和养分吸收量大幅减少。
关键词:甘蔗;播种期;干物质;氮;磷;钾中图分类号:S566.1 文献标识码:AEffects of Planting in Different Months on Dry Matter and NutrientAccumulation of Sugarcane in Red SoilAll Rights Reserved.WEI Jianfeng1,2, WEI Dongping1*, HU Guijuan1, WU Xuanke3, LUO Xiaofen2, ZHAO Xiaoyu1,LIAO Wenqin1, ZHANG Ling11. Liuzhou Institute of Technology, Liuzhou, Guangxi 545616, China;2. Guangxi University of Science and Technology, Liuzhou,Guangxi 545006, China; 3. Agro-meteorological Experiment Station of Liuzhou, Liuzhou, Guangxi 545003, ChinaAbstract: Sugarcane is a very important cash crop in Guangxi. The planting area of sugarcane in Guangxi accounts forabout 60% of China. The improvement of sugarcane production efficiency in Guangxi is of great significance to thehealthy development of sugarcane industry in China. Planting date affects the growth and yield of sugarcane. Study onthe absorption and utilization of nitrogen, phosphorus and potassium in sugarcane at different planting date is expectedto provide a theoretical basis for the efficient fertilization and cost-saving production. A field experiment was conductedin 2019–2020 to study the effects of planting date on the dry matter accumulation, nutrient accumulation and nutrienteconomic efficiency of plant cane and first ratoon by using sugarcane cultivar ‘Guitang 42’. Depending on the main plant-ing month of sugarcane in Guangxi, four dates were set, including 15-February, 15-March, 15-April and 15-May. Withdelayed planting date, the total dry matter accumulation in different organs of plant cane decreased, that in roots and leavesof ratoon cane increased, but the dry matter accumulation in stalk of ratoon cane reached the highest in the 15-Marchplanting. The dry matter accumulation in stalk of two crops ranged from 51.88 to 66.43 t/hm2, and that in the planting in15-February and 15-March was higher, and the planting in 15-May was the lowest. The accumulation of nitrogen, phos-phorus and potassium in the root and stalk of plant cane was lower, as well as the total accumulation of nitrogen, phospho-rus and potassium, but the accumulation of nitrogen, phosphorus and potassium in the leaf was higher with the delaying of收稿日期 2021-08-24;修回日期 2021-11-29基金项目 国家自然科学基金项目(No. 31860593);广西自然科学基金项目(No. 2020GXNSFAA297015);柳州市科技计划项目(No. 2020PAAA0602)。
作物学报 ACTA AGRONOMICA SINICA 2018, 44(3): 454 462 /ISSN 0496-3490; CN 11-1809/S; CODEN TSHPA9E-mail: xbzw@本研究由国家科技支撑计划项目(2013BAD07B12), 国家重点研发计划项目(2016YFD0300501, 2017YFD0301601), 江西省科技支撑计划项目(2009BNA03800, 20171BBF60030)和中国博士后科学基金面上项目(2016M600512)资助。
This study was supported by the National Science & Technology Support Plan (2013BAD07B12), the National Key R&D Program (2016YFD0300501, 2017YFD0301601), the Jiangxi Science & Technology Support Plan (2009BNA03800, 20171BBF60030) and China Postdoctoral Science Foundation Program (2016M600512).*通信作者(Corresponding authors): 吴建富, E-mail: wjf6711@; 潘晓华, E-mail: xhuapan@第一作者联系方式: E-mail: zyh74049501@Received(收稿日期): 2017-05-28; Accepted(接受日期): 2017-11-21; Published online(网络出版日期): 2017-12-18. URL: /kcms/detail/11.1809.S.20171218.0925.012.htmlDOI: 10.3724/SP.J.1006.2018.00454机收稻草全量还田减施化肥对双季晚稻养分吸收利用及 产量的影响曾研华 吴建富* 曾勇军 范呈根 谭雪明 潘晓华* 石庆华江西农业大学双季稻现代化生产协同创新中心 / 作物生理生态与遗传育种教育部重点实验室, 江西南昌 330045摘 要: 稻草还田替代部分化肥对推进化肥零增长行动具有重要的意义。
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这篇文章是用来测量马铃薯在微波和对流干燥过程中的质量和结构变化。
微波炉经过改良后,选择微波或者对流干燥模式干燥样品。
脱水马铃薯样品的质量品质以抗坏血酸残留量(VC)、复水能力以及具有收缩性的结构为准。
抗坏血酸马铃薯品质的重要指标,且与热变性有关。
抗坏血酸的恶化标志着一级反应情况,进一步的研究表明,取决于空气温度、微波力、湿度含量。
在微波干燥样品中,VC含量破坏减少。
样品的体积皱缩度显示其与湿度的线性关系。
在对流加工过程中,样品自始至终都会出现收缩性,然而,我们却发现微波干燥有两个收缩周期。
微波干燥样品有更高的复水能力。
关键词:对流干燥; 微波干燥; 马铃薯; 复水; 缩水; 维生素C目录1.简介2. 材料与方法3. 结果与讨论3.1.维生素C3.2.收缩性3.3. 复水4.结论参考文献1.简介在微波加工过程中,食物品质是消费者关注的重要指标之一。
微波干燥食品可以提高复杂的化学转换、化学反应。
,这些反应可以导致维生素的分解,脂肪氧化和美拉德反应。
而这些反应机制可以受浓度、温度、水分活度(aw)影响(Bruin & Luyben, 1980)。
经调查研究发现,在微波烹调中维生素会有所减少。
Rosen (1972) 曾研究讨论了微波食品及其相关食料的作用影响,微波量子能在各能级范围内比其他形式的电磁能(X- 和γ-射线)能量都低,也就使得分子和化学集团相互作用从而引起化学变化。
Gerster (1989)把热敏感和水溶性的维生素C 、B1和B2作为指示器来定性分析化学变化。
食品在微波炉中的烫熟、加热以及再加热过程中其维生素残留量可与常规加热方法相比较。
研究发现抗坏血酸的破坏速率随着aw值增加而增加,在解吸附系统中由于粘度的降低破坏速度会大大增加(Labuza, McNally, Gallagher, & Hawkes, 1972)。
Kirk, Dennison, Kokoczka, and Heldman (1977)研究发现,在复水食品体系中,抗坏血酸的稳定性受水分活度、湿度、氧气、贮藏温度的影响。
第38卷㊀第6期2020年6月环㊀境㊀工㊀程Environmental EngineeringVol.38㊀No.6Jun.㊀2020碳氮比对蔬菜废弃物好氧发酵腐熟度及臭气排放的影响刘文杰1,2,3㊀王黎明1∗㊀沈玉君2,3㊀张㊀曦2,3㊀孟海波2,3㊀范盛远1,2,3㊀张大牛1,2,3(1.黑龙江八一农垦大学工程学院,黑龙江大庆163319;2.农业农村部规划设计研究院农村能源与环保研究所,北京100125;3.农业农村部资源循环利用技术与模式重点实验室,北京100125)摘要:为了提高蔬菜废弃物发酵效率㊁减少臭气排放㊁确定其好氧发酵最佳碳氮比,以蔬菜废弃物为主料㊁猪粪和玉米秸秆为辅料进行好氧发酵,设置C /N 为20㊁25㊁303个处理,探讨不同C /N 对发酵产品腐熟度及臭气排放浓度的影响,以温度㊁含水率㊁pH ㊁电导率(EC )㊁腐植酸光学特性(E 4/E 6值)㊁种子发芽指数以及全氮㊁全磷㊁全钾含量变化评价发酵产品的腐熟度㊂T1处理(C /N 为20)高温期持续时间最长为6d ,种子发芽指数最高为82.23%,其腐熟效果最好,且全氮㊁全磷㊁全钾含量分别提高了24.22%㊁78.94%㊁51.45%;从臭气排放浓度来看,T2(C /N 为25)处理组NH 3排放浓度最高达368000μg /m 3,T3(C /N =30)处理组H 2S 排放浓度最高达671μg /m 3,TI 处理TVOC 排放浓度最高,但最高与最低排放浓度差仅为4.3ˑ10-6㊂因此,建议蔬菜废弃物㊁猪粪㊁玉米秸秆联合好氧堆肥的C /N 为20,可满足好氧发酵无害化和减少臭气排放的要求㊂关键词:蔬菜废弃物;好氧发酵;碳氮比;腐熟度;臭气排放DOI:10.13205/j.hjgc.202006038㊀㊀㊀㊀㊀㊀㊀㊀收稿日期:2019-05-13基金项目:国家重点研发计划 好氧发酵过程重金属钝化及高效生物除臭关键技术与设备研究 (2016YFD0800603);校级创新科研项目 蔬菜废弃物好氧发酵臭气与氮素转化原位控制研究 (YJSCX2019-Y46)㊂第一作者:刘文杰(1995-),女,硕士研究生,主要研究方向为农业生物环境与能源工程㊂1309433909@ ∗通信作者:王黎明(1967-),女,博士,教授,主要研究方向为生物质技术与装备研究㊂dlidxy@EFFECTS OF CARBON TO NITROGEN RATIO ON MATURITY AND ODOREMISSION IN AEROBIC FERMENTATION OF VEGETABLE WASTELIU Wen-jie 1,2,3,WANG Li-ming 1∗,SHEN Yu-jun 2,3,ZHANG Xi 2,3,MENG Hai-bo 2,3,FAN Sheng-yuan 1,2,3,ZHANG Da-niu 1,2,3(1.College of Engineering,Heilongjiang Bayi Agricultural Reclamation University,Daqing 163319,China;2.Institute of Energy and Environmental Protection,Chinese Academy of Agricultural Engineering Planning &Design,Beijing 100125,China;3.Key Laboratory of Technology and Model for Cyclic Utilization from Agricultural Resources,Ministry of Agriculture and Rural Affairs,Beijing 100125,China)Abstract :In order to improve the fermentation efficiency of vegetable waste and reduce the emission of odor to determine theoptimal carbon nitrogen ratio of aerobic fermentation.Aerobic fermentation was carried out with vegetable waste as the mainmaterial,and pig manure and corn straw as the auxiliary materials.Three C /N ratios (20,25and 30)were set to investigate their effects on maturity and odor emission concentration of fermented products.Temperature,moisture content,pH,electricalconductivity (EC),E4/E6,seed germination index and total nitrogen,total phosphorus and total potassium content were usedto evaluate the maturity of fermented products.The results showed that:in T1treatment (C /N =20),the longest duration of high temperature period was 6days,the seed germination index was up to 82.23%;then its maturation effect was the best,and the content of total nitrogen,total phosphorus and total potassium were increased by 24.22%,78.94%and 51.45%respectively.In terms of odor emission concentration,the highest emission concentration of NH 3appeared in T2(C /N =25)环㊀境㊀工㊀程第38卷treatment group,368000μg/m3,the highest emission concentration of H2S appeared in T3(C/N=30)treatment group, 671μg/m3;the highest TVOC emission concentration appeared in T1treatment group,but the maximum difference of TVOC emission concentration between all groups was only4.3ppm.Therefore,it was suggested that the optinum C/N ratio of vegetable waste,pig manure and corn straw combined with aerobic compost was20,which could meet the requirements of harmless aerobic fermentation and reduce the emission of odor.Keywords:vegetable waste;aerobic fermentation;carbon to nitrogen ratio;maturity;odor emission0㊀引㊀言据中国蔬菜协会统计,2019中国蔬菜产量达7.69亿t,高产的同时也造成大量蔬菜废弃物的产生[1]㊂蔬菜废弃物养分丰富,其含氮量(烘干基)约为3.5%,磷含量约为0.4%,钾含量约为3.6%[2]㊂大量蔬菜废弃物的丢弃,造成了极大的资源浪费,而且蔬菜长期堆放会被病原菌间接或直接浸染,造成病原菌传播,危害环境及人类健康[3]㊂目前,蔬菜废弃物资源化利用的主要途径有直接还田㊁好氧发酵㊁沼气化利用㊁简易厌氧沤肥㊁饲料化利用,其中好氧发酵是蔬菜废弃物无害化处理和资源化利用的有效途径[1,4]㊂好氧发酵过程中会产生恶臭气体,一方面是由于堆体内部通风不均匀导致部分厌氧,产生H2S 以及大量的VOCs;另一方面在好氧环境下,有机物降解会产生氨气[5]㊂由于蔬菜废弃物含水率较高,C/N较低,结构性差,易腐烂变质,难以单独进行好氧发酵资源化利用[6],需添加畜禽粪便和农作物秸秆,以调节混合物料的C/N㊁含水率㊁有机质㊁自由空域等指标在合理范围内,保证发酵产品的质量以及安全利用[7,8]㊂有研究表明,C/N对发酵产品的腐熟及臭气排放有重要影响[9,10],C/N过低,氨气大量挥发,会导致臭气浓度升高及氮元素大量损失,腐熟期滞后[11];C/N过高,则微生物分解缓慢,导致发酵周期延长,C/N为20~30有利于微生物的生长繁殖[12,13]㊂韩萌等[14]研究发现,污泥好氧发酵过程中,随着原料C/N升高,氨气的产生速率及浓度都降低;孟凡书[15]研究发现,改变污水处理中的C/N对VOCs的排放量有一定的影响, VOCs的排放量随着C/N增加而增加;刘超等[16]研究发现,牛粪㊁蘑菇渣㊁稻壳高温堆肥条件下的最佳C/N为25;刘成琛等[12]研究发现,采用猪粪-玉米秸秆混合堆肥,C/N为20时发酵产品的腐熟效果最好㊂目前,针对猪粪㊁牛粪㊁厨余垃圾等不同C/N比好氧发酵腐熟度研究较多[12,16,17],但对于蔬菜废弃物好氧发酵腐熟度和臭气排放浓度变化规律的研究较少㊂因此,本研究以蔬菜废弃物㊁猪粪㊁玉米秸秆为原料进行联合好氧发酵,设置3组不同C/N,探讨发酵产品腐熟度及发酵过程中臭气排放浓度及规律,以确定蔬菜废弃物好氧发酵的最佳C/N㊂1㊀试验部分1.1㊀试验材料供试蔬菜废弃物采自菜市场废弃蔬菜,包括大白菜㊁小白菜㊁菠菜㊁包菜㊁茼蒿㊁空心菜等叶菜类蔬菜,切割至3~5cm;供试猪粪取自北京市顺义区东华山村养殖场;玉米秸秆购自山东省济南市,粉碎机切割为1~3cm㊂供试材料的基本理化性质见表1㊂表1㊀试验材料基本理化性质Table1㊀Basic properties of experimental materials%材料TC TN含水率蔬菜废弃物39.48ʃ1.22 3.5ʃ0.2986.29ʃ0.48猪粪35.01ʃ0.27 2.87ʃ0.0672.31ʃ1.25玉米秸秆42.5ʃ0.410.76ʃ0.0617.61ʃ0.31 1.2㊀试验方法本试验采用密闭式强制通风好氧发酵工艺,堆肥采用60L好氧发酵装置,如图1所示㊂以蔬菜废弃物㊁猪粪㊁玉米秸秆为原料进行联合好氧发酵,设置3组处理,C/N分别为20㊁25㊁30,记为T1㊁T2㊁T3㊂各处理原料配比如表2所示,通风速率均为25L/min,经调节后含水率均在68%左右㊂试验周期为20d,在第1~7,9,11,15,17,20天采集气体;第0,1,4,7,9, 12,16,20天取固体样品150g,从上㊁中㊁下3点采样,保证样品具有代表性㊂样品分为2部分,一部分鲜样储存在4ħ的冰箱中待用,另一部分经冷冻干燥后碾磨过筛(80目)㊂发酵开始后,分别于第3,8,12天进行翻堆㊂表2㊀各处理原料配比Table2㊀Raw materials ratio of different treatments处理原料添加量/kg蔬菜废弃物猪粪玉米秸秆C/N T1105320T2105625T3105930432第6期刘文杰,等:碳氮比对蔬菜废弃物好氧发酵腐熟度及臭气排放的影响1 通风㊁温度控制系统;2 温度采集器;3 盖子;4 取样孔;5 保温层;6 物料填充区;7 筛板;8 渗滤液出口;9 气泵;10 排气孔;11 温度传感器㊂图1㊀好氧发酵装置示意Figure 1㊀Schematic diagram of aerobic fermentation device1.3㊀测定指标及方法1)温度:采用PT100探头电脑连接连续监测记录堆肥过程中温度变化㊂2)含水率:取5g 鲜样,置于精密鼓风干燥箱(上海慧泰仪器制造有限公司)105ħ下烘干6h㊂3)EC㊁pH 值㊁腐植酸光学特性E 4/E 6㊁种子发芽指数:首先将鲜样用去离子水浸泡,固液比为1ʒ10,振荡2h,离心过滤后取滤液㊂采用DDS-307A 型电导率仪(上海精密仪器仪表有限公司)测定EC 值;采用PHS-3C 型pH 计(上海精密仪器仪表有限公司)测定pH 值;E 4/E 6用UV752型紫外分光光度计(上海佑科仪器仪表有限公司)在465nm 和665nm 处测定各自吸光值后做比值;种子发芽指数的测定是取滤液5mL 于垫有滤纸的培养皿中,加入10粒颗粒饱满的小白菜种子,放入25ħ的HWS 型培养箱(北京中兴伟业仪器有限公司)中培养72h,计算方法见式(1):GI =浸提液种子发芽率ˑ根长对照组种子发芽率ˑ根长ˑ100%(1)4)全氮采用凯式定氮法(LY /T 1228 2015)测定[18];全磷采用碱熔法(LY /T 1232 2015)测定[19];全钾采用酸溶法(LY /T 1234 2015)测定[20]㊂5)氨气用2%的硼酸溶液吸收后,采用0.05mol /L 的HCl 滴定㊂6)H 2S 采用亚甲基蓝分光光度法测定㊂7)TVOC 采用复合气体测试仪测定(用异丁烯标定)㊂2㊀结果与讨论2.1㊀不同处理好氧发酵物料腐熟度指标的变化2.1.1㊀温度和含水率的变化发酵温度不仅直接影响堆体内部微生物的生长和种类,还与发酵周期有关,是好氧发酵无害化的一个重要标志[21,22]㊂图2是不同处理好氧发酵过程中温度和含水率变化㊂由图2a 可知:环境温度在10ħ左右时,T2㊁T3处理堆体温度在发酵第1天可达50ħ以上,但高温期维持时间均较短,随后温度持续下降接近室温,未达到好氧发酵GB 7959 2012‘粪便无害化卫生要求“㊂T1处理组在发酵第3天达到50ħ以上,高温期持续6d,且在发酵第6㊁7天温度达到70ħ以上,说明C /N 为20有利于微生物分解有机物,为堆体提供热量㊂一般认为,畜禽粪便好氧发酵高温期在50ħ以上须持续至少10d,才能达到无害化标准[23];也有研究表明,蔬菜废弃物好氧发酵高温须达到70ħ以上,才能杀灭病毒性病原菌[6]㊂T2㊁T3处理高温期持续较短,一方面是由于秸秆添加量大,木质素含量高较难分解,多余的碳不能被微生物完全利用;另一方面由于堆体内孔隙度较大,温度易散失,高温难以维持[24]㊂含水率是影响好氧发酵的重要因素,由图2b 可知:各处理均呈现先升高后降低的趋势㊂由于蔬菜自身含水率较高,尽管以玉米秸秆来调节含水率,但在发酵过程中蔬菜废弃物会不断地析出水分,导致升温期堆料含水率升高,随着温度的升高加快了水分散失[25]㊂发酵结束时各处理含水率分别为64%㊁61%㊁53%,T3处理含水率下降最多,是由于T3秸秆添加量最高,堆料孔隙度较大有利于水分散失[26]㊂2.1.2㊀pH 值和电导率(EC)的变化pH 值可影响微生物分解有机物的能力㊂图3是不同处理好氧发酵过程中pH 和EC 变化㊂可知:各处理pH 值先快速升高随后趋于平稳,这是由于微生物分解含氮有机物产生氨,且易挥发[12],最终各组pH 值分别为8.5㊁8.8㊁7.5,pH 在8~9堆体属于腐熟[27]㊂T3处理pH 值低于另外2组处理,是由于低C /N 会产生大量的NH 3[17]㊂发酵后期T1㊁T2处理pH 值再次升高,原因是翻堆为微生物分解有机酸及有机氮矿化提供了足够的O 2[28],而T3处理pH 值降低,是由于T3处理C /N 较高,有效氮源不足,堆体内532环㊀境㊀工㊀程第38卷ʏ C/N=20; Ә C/N=25; һ C/N=30㊂图2㊀不同处理好氧发酵过程中温度和含水率的变化Figure2㊀Variation of temperature and moisture content of differenttreatments during aerobic fermentation有机酸得到积累[29]㊂EC值反映好氧发酵物料中可溶性盐的浓度,肥料中高可溶性盐浓度可影响植物对水分的吸收[24]㊂由图3b可知:T1㊁T2处理EC值均<2mS/cm,T3处理最终EC值>4mS/cm,而EC值超过4mS/cm会对作物产生毒害作用[17,30]㊂各处理进入高温期后EC 值迅速上升,微生物分解有机物产生大量的无机盐[26]㊂T3处理秸秆添加量最高,木质素含量高较难分解,堆体中的可溶性盐含量低,电导率就越低,但其EC值却远大于另外2组处理,这与林皓等[24]研究结果不一致,此现象仍需进一步研究㊂2.1.3㊀腐植酸光学特性(E4/E6)的变化E4/E6可表现堆肥腐植酸分子的稳定程度,其值高低直接与腐植酸的分子大小或者分子的缩合度大小有关,一般随着堆肥液相(水浸提液)腐植酸相对分子质量或缩合度的减小而增加[31]㊂图4为不同处理好氧发酵过程中E4/E6变化㊂可知:最终各处理值E4/E6值分别为4.23㊁4.10㊁2.90㊂T1和T2处理, E4/E6值从高温期至堆肥结束呈上升趋势,随着发酵的进行,液相中的腐植酸相对分子质量和缩合度减ʏ C/N=20; Ә C/N=25; һ C/N=30㊂图3㊀不同处理好氧发酵过程中pH值和EC值的变化Figure3㊀Variation of pH and EC of different treatmentsduring aerobic fermentation小,小分子有机酸含量较高㊂T3处理中E4/E6值呈先升高后下降趋势,表明发酵后期小分子有机酸在向高分子的腐植酸转化㊂ʏ C/N=20; Ә C/N=25; һ C/N=30㊂图4㊀不同处理好氧发酵过程中E4/E6值的变化Figure4㊀Variation of E4/E6of different treatments duringaerobic fermentation2.1.4㊀种子发芽指数(GI)的变化种子发芽指数既能体现堆肥腐熟度又能反映其对种子的毒害程度,当种子发芽指数>50%时,表示发酵产品对种子基本无毒害;当>80%时,表示堆料达到632第6期刘文杰,等:碳氮比对蔬菜废弃物好氧发酵腐熟度及臭气排放的影响完全腐熟[32]㊂发酵初期种子发芽指数均为0,直至发酵结束,各处理GI 值分别为81.23%㊁71.81%㊁60.56%,均>50%,可达到对种子无害化要求㊂T1处理GI 最高,表明T1处理堆体物料腐熟程度最高㊂图5㊀不同处理种子发芽指数GI Figure 5㊀Variation of GI in different treatments2.1.5㊀全氮㊁全磷㊁全钾的变化好氧发酵是微生物不断分解有机物的过程,物料㊀㊀会产生浓缩效应[33],体积减少,因此,发酵后全氮㊁全磷和全钾含量因相对浓缩效应而增加[34-36]㊂图6是不同处理发酵开始和第30天间全氮㊁全磷㊁全钾变化㊂可知:各组全氮含量有不同程度的增加,最终分别提高了24.22%㊁22.53%和0.81%,这可能是由于NH 3挥发量小于物料相对浓缩全氮增量,与王亚飞等[37]研究结果一致㊂而T1处理全氮含量最高且增加幅度也最大,这由于堆肥中N 的损失70%是以NH 3-N 形式损失[38],T1处理氨气排放量最低,因此,其全氮含量相对较高㊂对于全磷含量,由图6b 可知:T1处理最终全磷含量提高了78.94%,T2㊁T3处理相较初始降低了20.80%和21.81%,是浓缩效应和淋溶作用损失共同作用的结果,T2㊁T3处理渗滤液损失减少的含量大于相对浓缩增加的含量[36]㊂对于全钾含量,由图6c 可知:堆肥中钾素不易流失,随着物料的降解与减少[37,38],最终各处理全钾含量分别提高了51.45%㊁99.19%和23.05%,与陈建军等[39]研究结果一致㊂第0天;第30天㊂图6㊀不同处理发酵开始和第30天全氮㊁全磷㊁全钾含量变化Figure 6㊀Total nitrogen,phosphorus and potassium contents in different treatments on beginning of fermentation and day 302.2㊀不同处理NH 3㊁H 2S ㊁TVOC 排放浓度的变化2.2.1㊀NH 3和H 2S图7为不同处理好氧发酵过程中NH 3浓度的变化㊂可知:在发酵初期,堆体表面NH 3浓度均为0,堆体处于厌氧发酵状态,之后随着温度的升高,堆体含氮有机物被微生物分解,产生大量NH 3,降温期阶段由于可降解有机物减少,因此NH 3排放浓度降低[29]㊂T2㊁T3处理在发酵第2天浓度达到最高,T1处理则在第4天浓度达到最高,说明NH 3排放浓度与温度有关㊂Pagans 等[40]研究发现,在好氧发酵中温阶段,NH 3的排放量与温度呈线性相关㊂各处理堆体表面NH 3最高浓度分别为89440,368000,240220μg /m 3,T1处理NH 3排放浓度最低,这与秦莉[41]研究结果不一致,可能是由于堆肥原料不同造成的㊂一般来说,C /N 低,氮素相对过剩,多余的氮会以NH 3的形式挥发出去[42],而本试验T1处理C /N 最低,其氨气排放浓度也最低,可能是由于氮素以其他形式被转化㊂H 2S 的产生是在氧气供应不足的条件下,厌氧菌对有机物分解不彻底的产物[5]㊂由图7b 可知:发酵初期堆体处于厌氧状态,H 2S 含量较高㊂随着好氧发酵的进行,强制性通风方式保证了堆体内生长微生物所需的氧气含量,在氧气充足的条件下,堆体进行好氧发酵,H 2S 浓度逐渐降低㊂发酵第7天,各处理H 2S 堆体表面浓度趋于稳定且几乎为0㊂H 2S 堆体表面最高浓度分别为446,125,671μg /m 3,其中T3处理H 2S 堆体表面浓度最高㊂2.2.2㊀TVOC好氧发酵过程中,有机物的不彻底分解,会产生732环㊀境㊀工㊀程第38卷ʏ C/N=20; Ә C/N=25; һ C/N=30㊂图7㊀不同处理好氧发酵过程中NH3浓度的变化Figure7㊀Variation of NH3during aerobic fermentation挥发性有机物VOCs㊂TVOC是3种影响室内空气品质污染中影响较为严重的一种[43]㊂图8为不同处理好氧发酵过程中TVOC浓度的变化㊂可知:随着发酵的进行,TVOC浓度呈先上升后下降趋势㊂各组TVOC最高浓度分别为28.5,25.6,24.2ˑ10-6,T1处理C/N较低,为好氧微生物生长提供的有效碳源不足[44],或由于高温期温度太高,大部分好氧微生物被杀死,导致有机物分解不彻底,产生大量的VOC㊂在好氧发酵中后期微生物活性逐渐增强,剩余的可分解有机物被分解,最终TVOC浓度降低㊂3㊀结㊀论1)从温度来看,只有T1处理(C/N=20)高温期持续时间最长;从其他腐熟指标来看,各处理均达到无害化要求,但T1处理腐熟效果最好;从全氮㊁全磷㊁全钾含量来看,T1处理氮磷钾最终含量均高于另外2组处理,分别提高了24.22%㊁78.94%㊁51.45%㊂2)NH3排放浓度最高的为T2处理,最高浓度达到368000μg/m3,H2S排放浓度最高的为T3处理,最高浓度达到671μg/m3,TVOC排放浓度最高为T1处理,但各处理组TVOC最高排放浓度差最大仅为ʏ C/N=20; Ә C/N=25; һ C/N=30㊂图8㊀不同处理好氧发酵过程中TVOC浓度的变化Figure8㊀Variation of TVOC in different treatments duringaerobic fermentation4.3ˑ10-6㊂由NH3㊁H2S和TVOC浓度变化特征可知:蔬菜废弃物好氧发酵臭气主要产生阶段为升温期和高温期阶段,随着物料的腐熟化进程,臭气浓度逐渐降低并趋于0㊂3)综合以上腐熟指标和臭气排放浓度,T1处理各项均达到堆肥无害化要求且发酵产品腐熟效果最好,臭气排放浓度相对较低㊂因此,建议将蔬菜废弃物㊁猪粪㊁玉米秸秆好氧发酵C/N调节为20,可满足堆肥无害化和臭气污染较少要求㊂参考文献[1]㊀刘玉升.设施蔬菜废弃物资源化与生态植物保护利用现状及前景[J].农业工程技术,2019,39(28):25-27.[2]㊀董永亮.果蔬废弃物厌氧处理产能实验研究[D].哈尔滨:哈尔滨工程大学,2008.[3]㊀王丽英,吴硕,张彦才,等.蔬菜废弃物堆肥化处理研究进展[J].中国蔬菜,2014(6):6-12.[4]㊀YOGEV A,RAVIV M,HADAR 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Effects of Nitrogen Application on Blast Resistance and Rice Blast on RiceQuality of Yangeng series Rice Varieties(Lines)CHE Xi-qing ,LI Zhen-yu ,XING Ya-nan ,GUO Li ,ZHANG Li-li ,SANG Hai-xu*(Liaoning Institute of Saline-Alkali Land Utilization,Panjin Liaoning 124010,China)Abstract:In order to explore the effect of nitrogen fertilizer reduction on rice blast control of Yangeng series rice varieties (lines)and the effect of rice blast on rice quality.25newly bred rice varieties (lines)of Yangeng series and Yanfeng-47were used for field tests.All varieties were transplanted at two levels of normal nitrogen application(180kg/hm 2)and 20%nitrogen reduction (144kg/hm 2)respectively to investigate the occurrence of rice panicle neck blast;The rice quality of Yanfeng-47was determined by collecting the diseased panicles of Yanfeng-47,which were not diseased under two nitrogen levels,and the diseased panicles whose disease index no less than grade 5at the normal nitrogen application level.The results showed that 20%reduction of nitrogen fertilizer application could reduce the occurrence of rice blast,and there was no significant difference in rice yield,processing quality,appearance quality and nutritional quality;The occurrence of rice blast can reduce the processing and appearance quality of rice such as brown rice rate,milled rice rate and head rice rate,as well as the nutritional quality such as protein content,amylose content,fatty acid content and taste value of rice.It can be seen that rice blast can affect rice quality,and 20%nitrogen reduction can reduce the occurrence of rice blast,thus improving rice quality without affecting rice yield.Key words :Nitrogenous fertilizer;Yangeng series;Blast resistance;Rice quality氮肥运筹对盐粳系列水稻品种(系)抗瘟性评价及稻瘟病对稻米品质的影响车喜庆,李振宇,邢亚楠,郭莉,张丽丽,桑海旭*(辽宁省盐碱地利用研究所,辽宁盘锦124010)摘要:为探究氮肥减施对盐粳系列水稻品种(系)稻瘟病控害效果及稻瘟病对稻米品质影响,以25个新选育的盐粳系列水稻品种(系)和盐丰47为试验材料进行田间试验。
19--耕作栽培•生理生化 引用格式: 胡杨,方玲,扶定,等. 氮密互作对信优糯721群体质量及产量构建的影响[J]. 湖南农业科学,2024(1):19-23. DOI:10.16498/ki.hnnykx.2024.001.004水稻是我国播种面积最大、总产最多、单产最高的粮食品种,在我国粮食生产和消费中历来处于主导地位[1]。
近年来,随着生活水平的不断提高,人们对稻米品质的要求越来越高[2]。
在绿色生产的前提下获得高产优质的稻米一直是农业生产者所追求的一大目标。
研究表明,优良的品种和配套栽培措施对作物产量的贡献率各占50%[3]。
在品种固定的情况下,科学有效的栽培管理是充分发挥品种高产优质潜力的关键因素[4-6]。
氮是构成蛋白质的主要成分,对茎叶的生长和果实的发育有重要作用,是与产量最密切的营养元素[7-9]。
要实现水稻优质、高产、高效、生态、安全相协调的生产目标,适宜的氮素水平至关重要。
同时,合理的移栽密度能较好地协调水稻群体与个体的矛盾,既有利于达到一定穗数的要求,又有利于发挥大穗的优势,是提高水稻植株光合作用和肥料利用率的必要条件[10]。
因此,适宜的氮密水平是维持水 氮密互作对信优糯721群体质量及产量构建的影响 胡杨,方玲,扶定,何世界,李慧龙,沈光辉,常幸远,段斌 (信阳市农业科学院,河南 信阳 464000)摘要: 为探明氮密互作对信优糯721群体质量、产量形成及稻米加工品质的影响,试验利用该品种设置4个氮肥处理水平,分别是A0(对照)、A1施氮180 kg/hm 2、A2 施氮240 kg/hm 2、A3施氮 300 kg/hm 2,设置 3 个移栽密度梯度,分别为 B1,21.5万穴/hm 2、B2,25.7万穴/hm2、B3,29.9万丛/hm 2。
结果表明:干物质积累量方面,同一氮素水平,随着移栽密度的增加呈现增加的趋势;同一移栽密度处理上,拔节期随着氮肥用量的增加干物质积累呈现增加的趋势,SPAD 值方面,各处理最大值均在始穗期;产量与氮肥施用量呈正相关,在一定的氮素水平下,有效穗均随着密度的增加呈现增加的趋势;结实率、千粒重随着密度的增加呈现降低的趋势;出糙率、精米率和整精米率最大值均在A2B2处理且精米率和整精率与其他处理表现出显著差异,米粒长宽比受不同氮肥用量和移栽密度影响较小。
收稿日期:2023-10-26基金项目:广东省重点领域研发计划(2021B0707010006,2022B020*******);广东省现代农业产业技术体系专项(2023KJ105);广东省乡村振兴战略专项(2022-NPY-00-001);广东省水稻育种新技术重点实验室项目(2020B1212060047);广东省农业科学院中青年学科带头人(金颖之星)培养项目(R2023PY-JX003)作者简介:巫浩翔(1994-),男,硕士,研究实习员,研究方向水稻病理及抗病育种,E-mail:*************通信作者:何秀英(1974-),女,博士,研究员,研究方向为水稻遗传育种,E-mail:******************广东农业科学2023,50(12):52-61Guangdong Agricultural SciencesDOI:10.16768/j.issn.1004-874X.2023.12.005巫浩翔,陆展华,方志强,陈浩,王石光,王晓飞,刘 维,何秀英. 稻瘟病菌效应蛋白与水稻互作研究现状及展望[J]. 广东农业科学,2023,50(12):52-61.稻瘟病菌效应蛋白与水稻互作研究现状及展望巫浩翔,陆展华,方志强,陈 浩,王石光,王晓飞,刘 维,何秀英〔广东省农业科学院水稻研究所/农业农村部华南优质稻遗传育种重点实验室(部省共建)/广东省水稻育种新技术重点实验室,广东 广州 510640〕摘 要:水稻是世界上最重要的粮食作物之一,水稻安全生产关乎食品安全问题。
由稻瘟病菌引起的稻瘟病是一种世界性的真菌病害,给水稻生产造成严重损失。
相较于药物防治,抗病品种的培育与应用是控制该病害最为经济有效的方法。
然而,田间稻瘟病菌群体复杂多样、杀菌剂过量施用、气候环境变化等因素造成小种变异迅速,品种的抗性往往只能维持3~5年。
稻瘟病菌通过无毒基因的变异产生新的生理小种,逃逸或抑制水稻的免疫系统,实现侵染致病。
王丹阳,王洁,张本华,等.基于介电特性的稻谷干燥含水率检测模型构建与验证[J].沈阳农业大学学报,2022,53(6):752-758.沈阳农业大学学报,2022,53(6):752-758Journal ofShenyang Agricultural University http ://DOI:10.3969/j.issn.1000-1700.2022.06.015收稿日期:2022-02-10基金项目:国家重点研发计划项目(2018YFD0300307);农业部农产品产后处理重点实验室开放课题项目(KLAPPH2-2017-02)第一作者:王丹阳(1977-),女,博士,副教授,从事农产品加工工程相关研究,E-mail:************.cn 通信作者:张本华(1971-),男,博士,教授,博士生导师,从事农业机械智能化检测与控制技术相关研究,E-mail:************.cn基于介电特性的稻谷干燥含水率检测模型构建与验证王丹阳1,2,王洁1,张本华3,赵名策1,冀东平1,战廷尧1,冯龙龙1,郝吉明4[1.沈阳农业大学工程学院,沈阳110161;2.农业农村部园艺作物农业装备重点实验室,沈阳110161;3.宿迁学院机电工程学院,江苏宿迁223800;4.中粮米业(沈阳)有限公司,沈阳110112]摘要:为建立稻谷通风干燥含水率在线监测系统,利用自制可替换平行极板电容器与阻抗分析仪构建系统测定模型,以辽-盐粳98为试验物料,测定不同极板材料、极板类型、极板绝缘性及通风网板网格尺寸条件下稻谷含水率与电容值间的数值关系。
首先探究极板材料与结构参数对电容值的影响,同时测定1×103~1×106Hz 频率段内稻谷的介电常数ε'与介质损耗因数ε"。
采用基于X-Y 共生距离(SPXY)算法划分样本集,对60个不同含水率稻谷样本按照比例2∶1划分为校正集和预测集,并利用无信息变量消除法(UVE )、UVE-SPA (连续投影法)联合筛选出ε'、ε"以及ε'和ε"结合变量的特征变量数及所选频率点,再以UVE 、SPA 和UVE-SPA 选取方法获得的频率数据作为因变量建立特征变量与含水率间支持向量回归(SVR )模型,最终对该支持向量机回归模型进行验证。
DOI:10.7524/j.issn.0254-6108.2023102601李云捷, 李佳, 陈振国, 等. 石蜡与氨基酸废母液粉配施对烟草重金属Cd吸附的阻控效应[J]. 环境化学, 2024, 43(4): 1365-1373.LI Yunjie, LI Jia, CHEN Zhenguo, et al. Blocking effect of paraffin wax and amino acid waste mother liquor powder on the adsorption heavy metal Cd of tobacco[J]. Environmental Chemistry, 2024, 43 (4): 1365-1373.石蜡与氨基酸废母液粉配施对烟草重金属Cd吸附的阻控效应 *李云捷1 李 佳1 陈振国2 李建平2 喻雪婧1 云月利1 孙光伟2 朱 蓉1 李亚东1 **(1. 湖北大学生命科学学院,武汉,430062;2. 湖北省烟草科学研究院,武汉,430033)摘 要 烟草是强富集镉(Cd)的重要经济作物. 为降低烟草对Cd的吸收,以矿区污染土壤(Cd含量为0.678 mg·kg−1)为种植基质,烟草专用肥(硝态氮)为对照,氨基酸母液粉为新型氮肥(氨基氮),并分别配施作为土壤微生物碳源的食品级石蜡,以期促进土壤微生物种群与数量的持续增加(石蜡降解速度缓慢),通过微生物的生化调控达到降低土壤有效态Cd含量,从而减少烟叶对镉的吸收. 结果表明:(1)石蜡和氨基酸废母液粉配施(T4处理)显著(P<0.05)提高土壤微生物丰富度,ACE指数达到4464.47,Chao1指数达到3888.30,氨基酸废母液粉(T3处理)土壤微生物多样性最好,Shannon指数达到6.4066;(2)施加氨基酸废母液粉(T3、T4处理)可显著(P<0.05)提高土壤pH值,3个时期(烟叶旺长期、打顶期、成熟期)最大提高量分别为0.23、0.49和0.35;(3)石蜡和氨基酸废母液粉显著(P<0.05)降低土壤有效态Cd含量,3个时期较烟草专用肥组(T1处理)分别降低了14.8%—20.7%、18.6%—34.5%、20.5%—36.7%;(4)石蜡和氨基酸废母液粉显著(P<0.05)降低烟叶Cd含量,3个时期较烟草专用肥(T1处理)分别降低了0.6%—10.2%、8.2%—26.2%、13.8%—38.9%. 因此,石蜡和氨基酸废母液粉配施能够有效提高土壤微生物丰富度和多样性,降低土壤有效态Cd含量,减少烟草对Cd的吸收.关键词 石蜡,氨基酸废母液粉,土壤微生物,烟草,镉.Blocking effect of paraffin wax and amino acid waste mother liquor powder on the adsorption heavy metal Cd of tobaccoLI Yunjie1 LI Jia1 CHEN Zhenguo2 LI Jianping2 YU Xuejing1 YUN Yueli1 SUN Guangwei2 ZHU Rong1 LI Yadong1 **(1. School of Life Science, Hubei University, Wuhan, 430062, China;2. Hubei Provincial Tobacco Research Institute,Wuhan, 430033, China)Abstract Tobacco is an important cash crop with strong enrichment of cadmium (Cd). In order to reduce the absorption of Cd by tobacco, the contaminated soil in mining area (Cd content is0.678 mg·kg−1) is used as planting substrate. In this experiment, tobacco special fertilizer (nitratenitrogen) was used as control, the amino acid waste mother liquor powder was a new nitrogen fertilizer (amino acid nitrogen), and paraffin wax (food-grade) as soil microbial carbon source was2023 年 10 月 26 日 收稿(Received:October 26,2023).* 湖北省烟草公司科技项目(027Y2021-024)资助.Supported by the Science and Technology Program of Hubei Tobacco Company (027Y2021-024).* * 通信联系人 Corresponding author,E-mail:*****************1366环 境 化 学43 卷applied separately. The purpose is to promote the continuous increase of soil microbial population and quantity (the degradation rate of paraffin wax is slow.), and reduce the soil available Cd content through biochemical regulation of microorganisms, thereby reducing the absorption of Cd by tobacco leaves. The results showed that: (1) Paraffin wax and amino acid waste mother liquor powder (T4 treatment) significantly (P<0.05) increased the soil microbial richness, the ACE reached 4464.47, the chao1 reached 3888.30, the amino acid waste mother liquor powder (T3 treatment) soil microbial Shannon diversity was the best, and the Shannon reached 6.4066; (2) the application of amino acid waste mother liquor powder (T3, T4 treatment) could significantly increase soil pH (P<0.05), and the maximum increases in the three periods were 0.23、0.49 and 0.35 units. (3) Paraffin wax and amino acid waste mother liquor powder significantly (P<0.05) reduced the soil effective Cd content, which was reduced by 14.8%—20.7%, 18.6%—34.5% and 20.5%—36.7%compared with the tobacco special fertilizer group (T1 treatment) in the three periods. (4) Paraffin wax and amino acid waste mother liquor powder significantly (P<0.05) reduced the Cd content of tobacco leaves, and decreased by 0.6%—10.2%, 8.2%—26.2% and 13.8%—38.9% compared with tobacco special fertilizer (T1 treatment) in the three periods. Therefore, the combination of paraffin wax and amino acid waste mother liquor powder can effectively improve the richness and diversity of soil microorganisms and reduce the soil effective Cd content. Finally, the absorption of Cd by tobacco is reduced.Keywords paraffin wax,amino acid waste mother liquor powder,soil microorganisms,tobacco,cadmium.镉(Cd)可通过食物链逐层积累,对生态环境和生物生命健康存在威胁[1]. 据2021年生态环境部发布简况,影响农用地土壤环境质量的主要污染物是重金属,其中镉为首要污染物. 烟草极易吸收Cd[2],Cd胁迫对烟草整个生长周期和生理指标均产生影响,严重降低烟叶口感和产量,且Cd通过烟气进入人体,威胁人体健康[3],因此如何降低烟草吸收Cd是烟草行业亟需解决的问题. 阻控烟草吸收Cd已有不少研究,如李晓锋等[4]发现, 生物有机类钝化剂提高烟草生物量且降低Cd吸收最显著;杜甫等[5]利用新型丙烯酰胺/羧甲基纤维素/生物炭复合水凝胶,提高了烟草在Cd胁迫下的耐受性;吕怡颖等[6]发现镉浓度50—200 μmol·L−1对烟苗生长发育具有显著抑制作用,外源褪黑素(一种小分子吲哚胺类)可显著缓解烟草镉毒害. 但相关研究尚未得到广泛应用,有可能是成本较高或对土壤存在二次污染[7];与此同时,土壤微生物阻控植物吸收重金属已卓有成效[8].本研究以曾应用于氨基酸、有机酸发酵工业的石蜡(食品级,碳原子13—18)[9]作为土壤微生物生长碳源,以期在氨基酸废母液粉作为氮肥的基础上,通过配施石蜡,促进石蜡降解菌群增加,全面提高土壤微生物种群数量,利用土壤微生物对镉离子的络合、螯合、沉淀等作用[10],降低Cd的迁移能力和有效态Cd含量,从而减少烟草对镉的吸收,为轻度镉污染土壤种植合格烟叶提供新的栽培技术.1 材料与方法(Materials and methods)1.1 实验材料实验于2022年11月22日在湖北大学生命科学学院全智能温室开展,供试烟草品种为云烟87,土壤取自黄石市矿区,其中含镉0.678 mg·kg−1,pH为5.15.1.2 实验设计施肥量纯氮97.5 kg·hm−2,m(N)∶m(P2O5)∶m(K2O)=1∶1∶1.5,移栽前一个月将肥料与土混合均匀,于2022年11月22日移栽烟苗至塑料盘内,塑料盘尺寸为32 cm×30 cm(直径×高). 实验设置4个处理,如表1所示其具体施肥方案:T1(只添加烟草专用肥)、T2(添加烟草专用肥+石蜡)、T3(只添加氨基酸废母液)、T4(添加氨基酸废母液+石蜡). 其中,石蜡采购自荆门市维佳实业有限公司,维佳58#食品级石蜡;氨基酸废母液粉为实验室自主研发的有机肥料,含氮≥14%;烟草专用肥购自烟台云天化肥公司,货号复合肥料(硫酸钾型/含硝态氮),含氮≥24%. 按比例配施磷钾肥,充分粉碎,在移栽前30天和移栽后45 d分两次施入土壤. 每个处理9株烟苗作为重复,遵循完全随机原则,其他所有处理栽培条件按照优质烟草生产方式进行.表 1 具体施肥方案Table 1 The specific fertilization scheme处理Treatment烟草专用肥Tobacco special fertilizer氨基酸废母液粉Amino acid mother liquor powder石蜡Paraffin waxT1406.2 kg·hm−2——T2406.2 kg·hm−2—300 kg·hm−2 T3—696.45 kg·hm−2—T4—696.45 kg·hm−2300 kg·hm−21.3 样品采集1.3.1 土壤样品采集烟苗移栽后45 d、75 d、105 d利用“S”形5点取样法采集根际土壤样品,近烟株根部10 cm、直径3 cm、深度12 cm的根际土壤样品,重复3次. 取移栽后75 d的根际土壤样品100 g装入无菌袋中迅速放入干冰盒中,-80℃保存,待测根际土壤微生物;其他样品风干粉碎后过200目筛,遵循土壤检测标准进行制备[11],待测土壤pH值、土壤有效态Cd含量.1.3.2 烟叶及烟株根茎样品采集烟苗移栽后45 d、75 d、105 d采集烟叶样品,其中移栽后45 d取第6叶位;移栽后75 d取上部叶(第4、5叶位)、中部叶(第10、11叶位)、下部叶(第15、16叶位);待烟叶均匀落黄后,移栽后105 d同移栽后75 d取样,叶位均为从上往下数,取样时随机选取一株两片烟叶样品混合为1个生物学重复,重复3次. 烟叶用蒸馏水洗净、擦干,105 ℃杀青30 min,65 ℃烘干至恒重,剔去主脉,剩余叶片粉碎后过200目筛,待测烟叶Cd含量. 烟叶全部采摘后,取烟株茎部上中下3个部位混合为一个生物学重复,重复3次,蒸馏水洗净擦干,烘干至恒重,粉碎后过200目筛,待测茎部镉含量;取烟株根部须根,每3株作为一个生物学重复,重复3次,蒸馏水洗净擦干,烘干至恒重,粉碎后过200目筛,待测根部Cd含量.1.4 测定项目与方法1.4.1 根际土壤微生物的测定采集好的根际土壤样品委托上海美吉生物科技股份有限公司进行微生物测序,其中,对细菌的16rRNA的V3-V4区进行PCR扩增,具体引物序列见表2,采用Vsearch[12]方法对序列进行处理,从而对样本中的所包含的高质量系列进行统计. 通过稀疏的方法对OTU丰度进行抽样[13],获得每个样本中的微生物群落各分类水平的具体组成数据.表 2 土壤微生物实时定量 PCR 分析基因及引物Table 2 Real-time quantitative PCR analysis of genes and primers by soil microorganisms区域Region引物名称Primer name引物序列(5’-3’)Primer sequences (5'-3')V3+V4341F CCTAYGGGRBGCASCAG 806R GGACTACNNGGGTATCTAAT1.4.2 根际土壤pH值测定参照《中华人民共和国国家环境保护标准(土壤 pH 值的测定电位法)》 (HJ 962—2018)[14]中土壤pH值测定方法,土水比为1:2.5(m:V),200 r·min−1振荡2 min,静置30 min,pH计(德国赛多利斯Sartoriu,PB-10)测定.1.4.3 根际土壤有效态Cd含量的测定土壤有效态Cd含量测定参照《土壤质量:有效态铅和镉的测定-原子吸收法》(GB/T 23739—2009)[15]测定.4 期李云捷等:石蜡与氨基酸废母液粉配施对烟草重金属Cd吸附的阻控效应13671.4.4 烟叶及烟株茎、根部Cd含量的测定烟叶及烟株茎、根部Cd含量测定参照《食品安全国家标准:食品中镉的测定》(GB/T 17141—1997)[16]测定.1.5 数据分析采用Microsoft Excel 2019进行数据处理和作图,采用SPSS 26.0进行数据分析,采用GraphPad Prism 9作图.2 结果与讨论(Results and discussion)2.1 不同处理对植烟土壤微生物群落组成的影响2.1.1 根际土壤微生物OTU丰度和α多样性在97%相似水平条件下得到土壤微生物群落物种多样性指数如表3所示,所有处理的覆盖率均大于0.95,说明测序能力能够真实反映土壤微生物群落特征. T1、T2、T3、T4处理下土壤微生物Sobs、ACE、Chao1指数均表现为T4>T3>T2>T1,T4处理组ACE指数达到4464.47,Chao1指数达到3888.30,Shannon指数表现为T3>T4>T1>T2,T3处理组Shannon指数达到6.4066. Simpson指数表现为T2>T1>T4>T3. 由α多样性可以看出,T4处理土壤微生物丰富度最高,T3处理土壤微生物多样性最好.表 3 不同处理根际土壤微生物α多样性指数Table 3 α Diversity index of soil microorganisms with different treatments处理Treatment Sobsα多样性指数α diversity index覆盖率Coverage Shannon Simpson ACE Chao1T12643.00b 6.3583a0.0098a3851.65b3571.71a0.9548T22714.33b 6.3359a0.0099a3864.72b3638.19a0.9551T32891.33a 6.4066a0.0086b4118.76b3787.24a0.9597T42914.00a 6.3752a0.0092ab4464.47a3888.30a0.9515 注:同列不同小写字母表示组间差异达显著水平(P<0.05)水平. Note: Different lowercase letters in the same column indicate a significant difference between groups (P<0.05) level.2.1.2 不同处理对根际土壤微生物群落组成的影响图1展示了门水平上平均相对丰度前五的类群(放线菌门、绿弯菌门、变形菌门、酸杆菌门和厚壁菌门),其中放线菌门(Actinobacteriota)在各处理中均占绝对优势,其次是绿弯菌门(Chloroflexi)和变形菌门(Proteobacteria). 放线菌门的相对丰度表现为T4>T2>T3>T1,其平均丰度与添加石蜡呈正相关;绿弯菌门的相对丰度表现为T3>T4>T1>T2,其平均丰度与添加氨基酸废母液粉呈正相关;变形菌门的相对丰度表现为T1>T2>T3>T4,与增施氨基酸废母液和石蜡均呈负相关.图 1 不同处理的微生物门水平上的相对丰度柱状图Fig.1 Histogram of relative abundance at the level of microbial phylums with different treatments 属分类水平上,根据所有样品的物种注释及丰度信息,选取根际土壤微生物丰度排名前20的物种,并按照其丰度信息绘制热图(图2),结果表明T1与T2、T3与T4处于同一分支,2组土壤微生物群1368环 境 化 学43 卷4 期李云捷等:石蜡与氨基酸废母液粉配施对烟草重金属Cd吸附的阻控效应1369落结构相似,说明氨基酸废母液粉是影响微生物群落结构的主要原因. 其中戈登式菌属(Gordonia)、分枝杆菌属(Mycobacterium)受是否添加石蜡影响较大,在T2和T4处理中的相对丰度较高,与其他两个处理存在极显著性差异;节杆菌属(Aothrobacter)、芽孢杆菌属(Bacillus)受是否添加氨基酸废母液粉影响较大,在T3和T4处理中的相对丰度较高,与其他两个处理存在显著性差异;而戴氏菌属(Dyella)受烟草专用肥影响较大,在T1和T2处理中的相对丰度较高,较其他两个处理相对丰度显著升高.图 2 不同处理的微生物属水平上优势菌属的层次聚类分析热图.注:颜色变化可以反映不同处理间在属水平上群落组成的相似性和差异性;右侧图为颜色梯度代表的数值Fig.2 Hierarchical clustering analysis heat map of dominant genera at the level of microorganisms with different treatments. Note: Color variations can reflect similarities and differences in community composition at genera levels between treatments;the graph on theright shows the numerical values represented by the color gradient随着微生物种群数量的增加,微生物细胞壁、胞外物质和胞内细胞器均起到降低重金属有效态作用,减少植物吸收,从而达到生态学方向的原位钝化作用. 本研究中发现增施氨基酸废母液粉和石蜡可提高根际土壤微生物丰富度和多样性(表3),这是由于氨基酸废母液粉作为有机肥提供小分子氮源,石蜡作为烃类物质提供碳源,两者相互促进微生物的生长繁殖,这与张慧、万连杰等证明氮肥和有机肥可有效提高土壤微生物丰富度的结果一致[17 − 19],且石蜡的存在会提高分解石蜡的烃类微生物. 在属水平上,节杆菌属和芽孢杆菌已被证明对重金属有钝化作用,尤其对重金属镉[20 − 21];戈登式菌属具备生物降解烃类物质的能力[22],且戈登式菌属和分枝杆菌属细胞壁中富含霉菌酸,使得细胞表面疏水性和渗透性极差,进而阻止重金属离子的渗透,可在重金属胁迫的环境下正常生长繁殖[23]. 可见,氨基酸废母液粉和石蜡可有效提高土壤微生物丰富度和多样性,从而降低土壤中有效态Cd含量,但对于是胞外物质还是胞内细胞器或各种酶对吸附、包埋重金属起作用还有待进一步研究.2.2 不同处理对各时期根际土壤pH值和土壤有效态Cd含量不同处理对各时期土壤pH值变化如图3a所示. 在烟株的各个生育期土壤pH均表现为氨基酸废母液粉组大于烟草专用肥组,表明增施氨基酸废母液粉可提高土壤pH值,但添加石蜡对土壤pH值无显著影响,其中移栽后45 d时pH提高量最高可达0.23,移栽后75 d时pH提高量最高可达0.49,移栽后105 d时pH提高量最高可达0.35,均具有显著性差异(P<0.05),而且所有施肥处理的土壤pH值都随着烟株的生长呈先升高后降低的变化. 不同处理对各时期植烟土壤有效态镉的影响如图3b所示. 移栽后45 d土壤有效态镉含量表现为T1>T3>T2>T4,T2、T3和T4处理较T1处理显著降低了16.6%、14.8%、20.7%,其他处理间无显著性差异;移栽后75 d土壤有效态镉含量表现为T1>T2>T4>T3,T2、1370环 境 化 学43 卷T3和T4处理较T1处理显著降低了18.6%、34.5%、31.5%,T3和T4处理较T2处理显著降低了13.4%、13.5%,在数值上T4>T3,但两处理间无显著性差异;移栽后105 d土壤有效态镉含量表现T1>T2> T3>T4,T2、T3和T4处理较T1处理显著降低了20.5%、36.6%、36.7%,T3和T4处理较T2处理显著降低了13.4%、13.5%,T3和T4处理间无显著性差异.图 3 不同处理对不同时期根际土壤pH值变化(a)和土壤有效态Cd含量变化(b)注:同组不同小写字母表示组间差异达显著水平(P<0.05)水平;其中45 d、75 d、105 d表示烟苗移栽后45 d、75 d、105 dFig.3 Changes of rhizosphere soil pH value (a) and changes of soil available Cd content at different periods of treatment (b)Note: Different lowercase letters in the same group indicate that the difference between groups reaches a significant level (P<0.05) level;Among them, 45 d, 75 d and 105 d indicated that 45 d, 75 d, 105 d after transplanting tobacco seedlings,土壤pH值对土壤中镉的形态影响较大[24],Wang等[25]研究表明,土壤pH较高时,镉主要以氧化物结合态及残留态形式存在,土壤pH较低时,氧化络合物中的镉会溶解,镉离子被释放,游离镉浓度上升. 本研究中氨基酸废母液粉可有效提高土壤pH值,3个生长时期可提高0.23—0.49,这是因为,氨基酸废母液粉是本实验室自主研发的有机肥料,由动物废毛发、骨头等动物蛋白通过氢氧化钾高温水解将蛋白质水解为小分子的氨基酸,肥料整体呈碱性,其次本研究减施磷肥可有效提高土壤pH值,防止土壤酸化,与龚玲婷结果一致[26].2.3 不同处理对各时期烟株镉含量2.3.1 对移栽后45 d烟叶镉含量不同处理对移栽45 d后烟叶Cd含量变化如图4(a)所示,在数值上Cd含量表现为T1>T2> T3>T4,但并无显著性差异,较T1分别降低了0.6%、7.1%和10.2%,表明在烟草生长前期各处理间对烟草吸收Cd的阻控并无太大差异.2.3.2 对移栽后75 d烟叶镉含量不同处理对移栽后75 d烟叶的Cd含量测定结果见图4(b). 移栽后75 d时各部位烟叶Cd含量均表现为T2>T1>T3>T4. 对于烟株下部叶,T4处理烟叶Cd含量显著低于T1处理,降低了26.2%;对于烟株中部叶,T3和T4处理显著低于T1和T2处理,较T1处理分别降低了8.2%、16.2%,较T2处理降低了6.8%、14.6%,且T3和T4处理间存在显著性差异;对于烟株上部叶,T3和T4处理显著低于T1处理,较T1处理分别降低了15.6%、18.7%,其他处理间无显著性差异. 结果表明,移栽后75 d氨基酸废母液粉可有效阻控烟草吸收Cd,且石蜡和氨基酸废母液粉配施对中部叶降Cd最为显著.2.3.3 对移栽后105 d烟叶、茎和根镉含量不同处理对移栽后105 d烟叶Cd含量测定结果见图4(c). 移栽后105 d时下部叶和中部叶Cd含量均表现为T1>T2>T3>T4,其中烟株下部叶,T3和T4处理显著低于T1和T2处理,较T1处理分别降低了23.0%、27.0%,较T2处理降低了19.0%、23.7%,且T3和T4处理间存在显著性差异;对于烟株中部叶,T2、T3和T4处理显著低于T1,较T1处理分别降低了14.3%、32.5%、38.9%,较T2处理降低了16.0%、21.6%,其他处理间无显著性差异;对于烟株上部叶,Cd含量表现为T2>T1>T3>T4,其中T3和T4处理显著低于T1处理和T2处理,较T1处理分别降低了13.8%、31.4%,较T2处理降低了23.7%、18.9%,且T3和T4处理间存在显著性差异.图 4 移栽后45 d(a)、75 d(b)和105 d(c)烟叶Cd 含量变化图注:同组不同小写字母表示组间差异达显著水平(P <0.05)水平;Fig.4 Changes of Cd content of tobacco leaves at 45 d(a), 75d(b) and 105 d(c) aftertransplanting with different treatmentsNote: Different lowercase letters in the same group indicate that the difference between groups reaches a significant level (P <0.05) level 不同处理对移栽后105 d 烟株茎部Cd 含量测定结果见图5(a ),茎部Cd 含量表现为T1>T2>T3>T4,T2、T3和T4处理显著低于T1,较T1处理分别降低了30.9%、38.1%、39.4%;不同处理对移栽后105 d 烟株根系Cd 含量测定结果见图5(b ),根系镉含量表现为T1>T3>T2>T4,T2、T3和T4处理均显著降低烟株根系Cd 含量,较T1分别降低了28.5%、27.9%和31.2%,但3个处理之间无显著性差异.图 5 不同处理对移栽后105 d 烟草茎部Cd 含量变化(a )和烟草根部Cd 含量变化(b )注:同组不同小写字母表示组间差异达显著水平(P <0.05)水平Fig.5 Changes of Cd content of tobacco stems (a ) and changes of Cd content of tobacco roots (b )at 105 days aftertransplanting with different treatmentsNote: Different lowercase letters in the same group indicate that the difference between groups reaches a significant level (P <0.05) level结果表明,石蜡和氨基酸废母液配施对烟草阻控Cd 是有效地,尤其在移栽后105 d 即烟草成熟期,烟叶降低率最高可达39.0%,烟茎部降低率达到39.4%,烟根部降低率达到31.2%. 这可能是因为增施石蜡后,石蜡缓慢的被微生物分解,持续提供微生物碳源,使土壤微生物对镉离子持续吸附,从而达到降低烟叶中Cd 的效果. Cd 在烟叶中的分布呈现上部叶>中部叶>下部叶,烟茎部>烟根部,这可能是因为烟株有强的蒸腾作用,在由下而上的运输过程中镉元素逐步向烟株上部积累,这与李晓忠的研究结果一致[27].4 期李云捷等:石蜡与氨基酸废母液粉配施对烟草重金属Cd 吸附的阻控效应13713 结论(Conclusion)(1) 本研究通过增施石蜡(食品级)不仅增加了常规微生物种群数量而且新增戈登式菌属(Gordonia )微生物种群(石蜡降解专属菌群),因此与氨基酸废母液粉作为肥料配施时,为微生物吸附、结合、沉淀重金属建立生态学基础,也表明石蜡作为碳源提高土壤微生物种群数量的可行性.(2) 本研究通过配施石蜡和氨基酸废母液粉,提高土壤pH 值,改变Cd 的存在形态,降低土壤中有效态Cd 含量,从而阻控烟草对Cd 的吸收,为实现轻度镉污染土壤条件下烟草的安全种植提供新的栽培措施.参考文献(References)陈世宝, 王萌, 李杉杉, 等. 中国农田土壤重金属污染防治现状与问题思考[J ]. 地学前缘, 2019, 26(6): 35-41.CHEN S B, WANG M, LI S S, et al. Current status of and discussion on farmland heavy metal pollution prevention in China [J ]. Earth Science Frontiers, 2019, 26(6): 35-41 (in Chinese).[ 1 ]杨佳蒴. 氯化钠诱导根系木质化对烟草镉吸收的影响[D ]. 北京: 中国农业科学院, 2020.YANG J S. Effects of the sodium chloride induced root lignification on cadmium accumulation by tobacco [D ]. Beijing: Chinese Academy of Agricultural Sciences, 2020 (in Chinese).[ 2 ]SIEMIANOWSKI O, BARABASZ A, KENDZIOREK M, et al. 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Progress on the study of biodegradation of organic pollutants and adsorption of heavy metals with Arthrobacter strains [J ]. Environmental Science & Technology, 2017, 40(10): 89-97 (in Chinese).[20]XU S Z, XING Y H, LIU S, et al. Co-effect of minerals and Cd(II) promoted the formation of bacterial biofilm and consequentlyenhanced the sorption of Cd(II)[J ]. Environmental Pollution, 2020, 258: 113774.[21]LAORRATTANASAK S, RONGSAYAMANONT W, KHONDEE N, et al. Production and application of Gordonia westfalica GY40biosurfactant for remediation of fuel oil spill [J ]. Water, Air, & Soil Pollution, 2016, 227(9): 325.[22]王瑾, 王永刚, 朵建文, 等. 重金属污染物的微生物修复策略[J ]. 安徽农业科学, 2023, 51(18): 24-28.WANG J, WANG Y G, DUO J W, et al. Microbial remediation strategies for heavy metal contaminants [J ]. Journal of Anhui Agricultural Sciences, 2023, 51(18): 24-28 (in Chinese).[23]陈楠. 土壤pH 对镉在土壤—水稻系统中的迁移、积累与分布的影响[D ]. 长沙: 湖南农业大学, 2018.CHEN N. Effect of soil pH on accumulation and distribution of cadmium in soil-rice system [D ]. Changsha: Hunan Agricultural University, 2018 (in Chinese).[24]WANG J, WANG P M, GU Y, et al. Iron-manganese (oxyhydro)oxides, rather than oxidation of sulfides, determine mobilization of Cdduring soil drainage in paddy soil systems [J ]. Environmental Science & Technology, 2019, 53(5): 2500-2508.[25]龚玲婷. 矿物质调理剂对土壤磷素的固持作用及植物营养吸收的影响研究[D ]. 广州: 华南理工大学, 2018.GONG L T. Study on the effects of mineral conditioner on soil phosphorus retention and plant nutrient uptake [D ]. Guangzhou: South China University of Technology, 2018 (in Chinese).[26]李晓忠, 汤若云, 杨虹琦, 等. 外源铅镉在不同类型土壤中的转化形态及在烟株中分布研究[J ]. 现代农业科技, 2015(3):197-198,212.LI X Z, TANG R Y, YANG H Q, et al. Study on transforming morphology and distribution of exogenous Pb and Cd in different types of soil and tobacco plants [J ]. Modern Agricultural Science and Technology, 2015(3): 197-198,212 (in Chinese).[27]4 期李云捷等:石蜡与氨基酸废母液粉配施对烟草重金属Cd 吸附的阻控效应1373。
新课标英语高考试卷第一部分:听力(共两节,满分30分)第一节(共5小题;每小题1.5分,满分7.5分)听下面5段对话。
每段对话后有一个小题,从题中所给的A、B、C三个选项中选出最佳选项,并标在试卷的相应位置。
听完每段对话后,你都有10秒钟的时间来回答有关小题和阅读下一小题。
每段对话仅读一遍。
1. What does the woman want to do?A. Go for a walk.B. Watch TV.C. Read a book.2. Where are the speakers?A. In a library.B. In a bookstore.C. In a classroom.3. How much will the man pay?A. 10.B. 15.C. $20.4. What is the man's favorite sport?A. Football.B. Basketball.C. Tennis.5. When will the meeting start?A. At 9:00.B. At 9:30.C. At 10:00.第二节(共15小题;每小题1.5分,满分22.5分)听下面5段对话或独白。
每段对话或独白后有几个小题,从题中所给的A、B、C 三个选项中选出最佳选项,并标在试卷的相应位置。
听每段对话或独白前,你将有时间阅读各个小题,每小题5秒钟;听完后,各小题将给出5秒钟的作答时间。
每段对话或独白读两遍。
听第6段材料,回答第6、7题。
6. What is the relationship between the two speakers?A. Husband and wife.B. Father and daughter.C. Brother and sister.7. What are they going to do this weekend?A. Go to the park.B. Visit their parents.C. See a movie.听第7段材料,回答第8至10题。
收稿日期:2020-05-20作者简介:刘春萍(1977-),女,湖北枣阳人,高级农艺师,主要从事种植业技术研究推广工作,(电子信箱)***************;通信作者,邱东峰,副研究员,主要从事水稻遗传育种研究,(电子信箱)**************。
水稻稻曲病(Rice false smut )是由稻曲菌[Usti⁃laginoidea virens (Cooke )Tak.]引起的水稻孕穗期穗部的真菌性病害。
自1878年Cooke 首次在印度发现以来,现已广泛分布于亚洲、欧洲、美洲、非洲等水稻主产区的40多个国家,其中在中国、日本等亚洲国家发生较为严重[1]。
近年来,随着全球气候的变暖和杂交水稻的示范推广以及氮肥水平的不断提高,稻曲病的发病率逐年上升,已由水稻次级病害上升为主要病害之一,引起了国内外许多专家学者的关注[2]。
稻曲病不仅影响水稻产量和稻米米质,还对人畜的健康构成一定危害,极大地影响了水稻高产稳产和食品安全。
水稻稻曲病的防治和抗病机理研究日益成为人们关注和亟待解决的问题。
因此,有效控制水稻稻曲病的发生,对中国的稻米品质及粮食安全尤为重要。
1水稻稻曲病的分布及危害稻曲病是由半知菌亚门绿核菌属绿核菌[Usti⁃laginoidea virens (cooke )Tak.]引起的一种水稻穗期病害,又称伪黑穗病、谷花病、青粉病、黑球病等。
明朝时期李时珍最早在《本草纲目》中对该病有过记录,称之为“硬谷奴谷穗霉者”。
此病属于真菌性病害,多发生在水稻收成好的年份,农民误认为是丰年征兆,故有“丰收果”俗称。
近年来在中国及各地稻区普遍发生,且逐年加重,已成为水稻主要病害之一。
稻曲病在世界大多数稻区都有发生,中国早有水稻稻曲病研究进展刘春萍1,徐孜1,龚洪波1,金兴国1,魏静1,刘婧1,张拥军1,邱东峰2(1.襄阳市农业技术推广中心,湖北襄阳441200;2.湖北省农业科学院粮食作物研究所/粮食作物种质创新与遗传改良湖北省重点实验室,武汉430064)摘要:稻曲病是水稻后期发生的一种真菌性病害,在中国及世界各地均有发生,现已成为水稻的主要病害之一。
Field Crops Research 149(2013)33–39Contents lists available at SciVerse ScienceDirectField CropsResearchj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /f crEstimating nitrogen status of rice using the image segmentation of G-R thresholding methodYuan Wang,Dejian Wang ∗,Gang Zhang,Jun WangInstitute of Soil Science,Chinese Academy of Sciences,71East Beijing Road,Nanjing 210008,Chinaa r t i c l ei n f oArticle history:Received 15October 2012Received in revised form 7April 2013Accepted 7April 2013Keywords:Digital camera Visible spectrumImage processing technology Nitrogen nutrition Ricea b s t r a c tA camera can record spectral information of visible bands.In this study,a digital camera was used to take pictures of the canopies of 3rice (Oryza sativa L.)cultivars with 6different nitrogen (N)application rates.Canopy images were segmented by setting threshold values based on the magnitude and distribution of the green channel minus red channel (GMR)value,and then correlations were established between image feature parameters and the 3plant indices (i.e.,above-ground biomass,N content and leaf area index)before and after image segmentation.Results showed significant exponential relationships between the image parameters and the plant indices.Before the segmentation,the GMR values were closely related to the 3plant indices,with correlation coefficient of 0.93**,0.93**and 0.94**,respectively;while after the segmentation,the correlation coefficients between canopy cover (CC)and plant indices were 0.90**,0.91**and 0.95**,respectively.We conclude that GMR and CC will be valid indicators in the application of N diagnosis both for japonica and indica rice.And the canopy image segmentation method is fast in data processing and easily adaptable.©2013Elsevier B.V.All rights reserved.1.IntroductionAs nitrogen (N)is the most important nutrient essential for the growth of crops,raised N application rate can effectively increase crop yields.But when it comes to over application,it would also cause a series of environmental problems and even yield decrease (Wang et al.,2003;Zhu,2000).Obtaining crop N status timely not only enable farmers to increase nitrogen use efficency (NUE),but also reduce the water and atmospheric pollution caused by exces-sive N application (Miao et al.,2011;Peng et al.,2002).Chlorophyll meter (SPAD-502)has been extensively used in studies on nutrition diagnosis of various crops by rapid determi-nation of relative chlorophyll contents.Peng et al.(2006)showed that the real-time nitrogen management (RTNM)of rice depending on the SPAD threshold value improved NUE by 30%or more with-out affecting the yield.However,the measuring area of SPAD-502is only 6mm 2,and it has to do a large numbers of repeated deter-mination before a reliable result can be obtained (Blackmer and Schepers,1995).Moreover,SPAD readings vary sharply between crops,varieties and growth stages.Therefore,only after calibrationAbbreviations:CC,canopy cover;NRI,normalized redness intensity;NGI,nor-malized greenness intensity;GMR,green channel minus red channel;LNC,leaf nitrogen concentration;LNA,leaf nitrogen accumulation.∗Corresponding author.Tel.:+862586881253;fax:+862586881253.E-mail address:djwang@ (D.Wang).of its readings,can SPAD improve its applicability (Lin et al.,2010;Peng et al.,1993).Leaf nitrogen concentration (LNC)reflects in the leaf color intu-itively and is easy to obtain.Therefore,the indicators used by most of the researches on fertilization recommendation are LNC or rela-tive LNC,such as the application of portable chlorophyll meter and hyperspectral sensors.However,there are significant changes for LNC during the rice growing period,even in the case of excessive N (Zhao et al.,2006),so it is difficult to determine the N sta-tus without the ‘sufficiency indices’,which was calculated from readings of chlorophyll meter or other devices relative to well-fertilized reference plots (Bausch and Brodahl,2012;Hussain et al.,2000;Samborski et al.,2009).Leaf nitrogen accumulation (LNA)and above-ground N accumulation have also been used for fertil-ization recommendation in many researches besides the LNC.Li et al.(2010)also pointed out that N concentration varied with the amount of N as well as the amount of biomass,so N taken up early in crop development led to increased growth but lower N concen-tration than a similar amount of N taken up later,and he concluded that “the most successful indicators for crop N diagnosis are those that measure,or are correlated with,the mass of N per unit ground area”(Flowers et al.,2003;Ju and Christie,2011;Lukina et al.,1999).With the development of the remote-sensing technology in recent years,the technologies of satellite imagery,aero-photographing (Williams et al.,2010)and hyperspectral remote sensing (Hansen and Schjoerring,2003)are widely used in the stud-ies on nutrition diagnosis of crops.Being one of the most convenient0378-4290/$–see front matter ©2013Elsevier B.V.All rights reserved./10.1016/j.fcr.2013.04.00734Y.Wang et al./Field Crops Research149(2013)33–39tools for remote sensing of visible spectrum,digital cameras are also being widely used.The application of cameras in agricultural monitoring began in the1990s,mainly in automatic quality grad-ing of agricultural products(Zhang et al.,2011)and in detecting weeds(Gerhards and Oebel,2006),pests and diseases(Dammer et al.,2011).Kawashima and Nakatani(1998)obtained the nutri-ent status of plants based on the estimation of chlorophyll content using a portable color video camera,but they used manul image extraction method and it was highly subjective to human prefer-ence.Most of the researches on crop N diagnosis are based on taking vertical pictures using digital camera,and segment the images and extract various kinds of parameters,such as green/red(Adamsen et al.,1999)and canopy cover(Li et al.,2010).Rorie et al.(2011) took pictures of corn leaf with a digital camera under artificial light. The picture was calibrated with reference color and turned into HSV (hue,saturation and value)color space.Its feature parameter was found to have good relationship with N content in the leaf and yield of the crop.To diagnose N status of a crop,the application of digital cameras and image processing techniques is less expensive than the use of other techniques,such as hyperspectral remote sensing and SPAD meter.Moreover,the sample image in the former covers an area much bigger than a SPAD could.On the basis of previous researches, this paper proposes a method for segmenting images of rice canopy by setting threshold value based on the magnitude and distribution of green channel minus red channel(GMR)value,and analyzes the relationships of image feature parameters before and after image segmentation with above-ground biomass,N content and leaf area index(LAI).In addition,the effectiveness of this method to diagnose N status of rice is also explored.2.Materials and methods2.1.General information of the experiment siteThe experiment was laid out in the Changshu Agricultural Ecology Experiment Station,Changshu,Jiangsu,China(120◦42 E, 31◦33 N).Located in the humid subtropical climate zone,the station enjoys annually493KJ cm−2of solar radiation,1800h of sunshine, 1200mm of precipitation and4933◦C of cumulative temperature ≥10◦C.The soil type for thefield experiment site is the gleyed paddy soil of the Taihu Lake region,containing1.79g kg−1of total nitrogen(TN),0.93g kg−1of total phosphorus(TP),18.7g kg−1of total potassium(TK),30.8g kg−1of organic matter,123mg kg−1of alkalytic N,13.1mg kg−1of plant available P and121mg kg−1of plant available K and pH of7.4(1:2,soil:water)in the0–15cm soil layer.2.2.Experiment designThis study used data from two independently designed N fertilizer gradient experiments.Experiment I was a long-term site-specific rice–wheat rotation experiment that started in1997and had six treatments,i.e.,CK,N0,N1,N2,N3and N4,designed to receive0,0,180,225,270and315kg N ha−1in rice season,respec-tively,and20kg P ha−1and90kg K ha−1for all the treatments except CK,and four replicates for each treatment.The data were selected from the2011rice growing season(May–November)with Nanjing46(NJ46)cultivar.Experiment II was the one carried out in 2011with paddyfields in a rice–wheat rotation.It was designed to have six N application rates,two rice cultivars and three repli-cates for each treatment.The six N application rates were0,120, 180,240,270and300kg N ha−1.In addition to the N application, each treatment received20kg P ha−1and90kg K ha−1.The two rice cultivars involved were japonica rice,Nanjing45(NJ45)and hybrid Table1Sampling dates of the three rice cultivars and numbers of samples.Cultivars First time Second time Third time Fourth timeNJ458July(18)a21July(18)12August(18)18August b(18) NJ464July(24)21July(24)10August(24)30August(24) LYP98July(18)21July(18)12August(18)26August(18)a Number in parentheses represents sampling number.b NJ45was short in life cycle,so the interval between the third and fourth sam-plings was only6days.indica rice,Liangyoupeijiu(LYP9).For both experiments the N was split into three applications,40%as basal fertilizer,20%as tillering fertilizer and40%as ear fertilizer,and the K application was split into50%as basal fertilizer and50%as ear fertilizer,and the P was applied once as basal fertilizer.Otherfield managements followed the practices as in ordinary farmlands.2.3.Sample collection and measurementThe above-ground part of rice was sampled every15days or so from transplanting to earing stage in2011.A total of4sets of samples were collected(Table1).The sample were oven-dried and then analyzed for biomass and TN.On the same day LAI was measured using a canopy analyzer(SunScan System-SS1,Delta-T Devices Ltd.).TN was measured using the Kjeldahl method(Lu, 2000).On the same day or the following day of sampling,pictures of the rice canopy were taken using a digital camera(EOS50D,Canon. Inc.).The camera was positioned1m above the top of the canopy using a tripod.Aperture priority mode was selected and the cam-era was set at5.6aperture,100ISO,4900K white balance and auto-focus with theflash turned off.The pictures were taken at 12:00–13:00of an overcast day without direct sunlight and the illuminance was about30–50thousand lux.Thus,when using auto exposure the actual exposure time of the camera was1/500to 1/320s.Pictures were stored in CR2raw format with a resolution of4752×3168.2.4.Image segmentation and data analysisThe pictures taken before the canopy reached100%in coverage contained some non-canopy elements,like soil and plant residues. Therefore,analyses were done separately of images before and after segmentation.Unsegmented or intact images contained some non-canopy elements but the segmented ones contained only canopy.Images were displayed in the RGB color model,each pixels in the image represented by an RGB triplet(red,green,blue value).The segmentation of images was based on the difference of reflectance spectrum between green vegetation and soil in the visible band. Green vegetation had an intensive reflection peak in the green band, whereas soil did not cause any apparent change in albedo in the vis-ible band.Therefore,after the processing of green channel minus red channel of an image(Matlab,The MathWorks,Inc.),the differ-ence between the canopy and non-canopy area became obvious in GMR value(Wang et al.,2012).Fig.1(b)is a color scale image plot-ted on the basis of the GMR values;and the gradual change in color in the image represented the change in GMR value.The color of the canopy section was sharply different from that of the non-canopy section,so it is feasible to set a GMR threshold for segmentation of a picture.Once a threshold was set,pixels with GMR value higher than the threshold were sorted as the rice canopy and the rest as the background(soil or plant residues).A raw imagefile contains minimally processed data from the image sensor of a digital camera.Thefile saves settings of white balance,color saturation,contrast,and sharpness in it,but defersY.Wang et al./Field Crops Research149(2013)33–3935Fig.1.The image of a rice canopy captured by a digital camera and the same image processed using Matlab:(a)original image,(b)scaled green channel minus red channel (GMR)value and displays as image and(c and d)segmented images using GMR threshold15and30,respectively.Black portion of the images is regarded as non-canopy(soil and plant residues).the processing.Therefore,all the changes made on a raw imagefileare non-destructive.The images in CR2raw format were adjusted to be identical incolor saturation,contrast and brightness with Photoshop(AdobeSystems Inc.)and converted to JPGfiles.After that JPG imageswere processed with Matlab for calculation of feature parametersdirectly or after segmentation.The computation of parameters usedthe mean value of all the pixels in an image.Canopy cover(CC)is thepercentage of the number of pixels reflecting the canopy against thetotal of the whole image.Normalized redness intensity(NRI)andnormalized greenness intensity(NGI)are the proportion of red orgreen color intensity in all the three colors.GMR is the differencebetween green channel and red channel.G/R is greenness intensitydivided by redness intensity.GMR,NRI,NGI and hue(H)were cal-culated using the following equations(Jia et al.,2004;Kawashimaand Nakatani,1998;Rorie et al.,2011).R,G and B denote meanvalues of the red,green and blue channels,respectively.Data anal-ysis was done using the SPSS13.0(SPSS Inc.)and the correlationcoefficients were obtained with the Spearman correlation.GMR=G−R(1)NRI=RR+G+B(2)NGI=GR+G+B(3)HueIf max(RGB)=R,H=60×G−Bmax(RGB)−min(RGB)If max(RGB)=G,H=60×2+B−Rmax(RGB)−min(RGB)If max(RGB)=B,H=60×4+R−Gmax(RGB)−min(RGB)(4)3.Results3.1.Above-ground biomass,N content and LAI of different ricecultivarsAnalysis of variance of the N content indicated no significantdifference between the three cultivars(Table2).But the LAI ofLiangyoupeijiu(LYP9)was about43%and76%higher than that ofNanjing46(NJ46)and Nanjing45(NJ45),respectively.The biomassof LYP9was similar to that of the other two,but the differencebetween NJ45and NJ46was rather significant.3.2.Relationships between image feature parameters and rice Nstatus before image segmentationThe image feature parameters,i.e.,GMR,G/R,NGI,NRI and H,extracted from intact images were significantly correlated with riceplant indices(above-ground biomass,N content and LAI,Table3).Among them,GMR,G/R,NGI and H were positively correlated withthe three plant indices,while NRI was significantly but negativelycorrelated with plant indices.GMR had the highest correlation coef-ficient with biomass,N content and LAI,reaching0.93**,0.93**and0.94**,respectively,and followed by G/R and NGI(both about0.9),Table2Mean values of above-ground biomass(Biomass),nitrogen content(N content)andleaf area index(LAI)of the three cultivars.Cultivars Biomass(g m−2)N content(g m−2)LAI(m2m−2)SamplenumbersNJ46395.6b a8.44a 2.12a96NJ45285.9a7.36a 1.72a72LYP9363.9ab9.09a 3.03b72a Means within the same column followed by different letters were significantlydifferent according to the Tukey test(P<0.05).36Y.Wang et al./Field Crops Research149(2013)33–39Table3Spearman correlation coefficients between rice plant indices and the image feature parameters extracted from intact images.GMR G/R NGI NRI H Number ofsamples Biomass0.93**0.88**0.89**−0.42**0.19**240N content0.93**0.93**0.89**−0.53**0.14240LAI0.94**0.91**0.91**−0.45**0.22**240**P<0.01.while NRI and H had much lower correlation coefficient compared to the others.However,H had no significant relationship with N content.The image feature parameters,GMR and G/R,were well corre-lated with the three plant indices.This paper focuses on the analysis of the relationships between the two feature parameters and rice N status.Regression analysis showed that GMR and G/R had exponen-tial relations with the three plant indices(Fig.2),and the following exponential function was identified to bestfit the nonlinear rela-tionships:y=ae bx(5) where y is a dependent variable,representing above-ground biomass,N content or LAI,x is an independent variable,represent-ing GMR or G/R.Both a and b were parameters obtained by the least square method.Regression analysis was performed using the concatenation of the three cultivars,the R2between GMR and the three plant indices reached0.84,0.81and0.82,and that between G/R and the three were0.71,0.81and0.71(Fig.2).The feature parameters were in good exponential relations with above-ground biomass,N content and LAI(Fig.2).With the rice growth,GMR and G/R values of the whole image were getting higher.Fig.2clearly shows that the high-est value of GMR was around30and of G/R around1.4.When GMR and G/R reached the maximums,the plant canopy coverage of the image approached100%.Separate regression analyses between NJ45,NJ46and LYP9and plant indices are shown in Fig.2.The relationships between GMR and the above-ground biomass,N content and LAI of NJ45were highly significant with R2reaching0.93,0.93and0.95,respectively. The R2between GMR and the three plant indices of the three culti-vars ranged from0.79to0.95,and between G/R and the three plant indices of the three cultivars in the range of0.66–0.93.Different sampling dates,cultivars and N application rates did not influence the trends of the relationships.3.3.Relationships between image feature parameters and rice N status after image segmentationAccording to the distribution of GMR values in the canopy image,afixed threshold value was set at20for image segmen-tation.Significant relationships were found between the feature parameters extracted from the segmented images and the plant indices(Table4).The correlation coefficients of CC with above-ground biomass,N content and LAI reached0.90**,0.91**and0.95**, Table4Spearman correlation coefficients between rice plant indices and the image feature parameters extracted from segmented images.CC GMR G/R NGI NRI H Number ofsamples Biomass0.90**0.47**0.76**0.47**−0.58**0.44**240N content0.91**0.41**0.83**0.48**−0.69**0.55**240LAI0.95**0.35**0.76**0.42**−0.62**0.49**240**P<0.01.Table5Regression analysis between the rice plant indices and canopy cover(CC)using Eq.(5).Biomass N content LAI NJ46(n=96)Eq.y=37.3e4.5x y=0.84e4.36x y=0.14e5.06x RMSE a107 2.730.71R20.870.810.84NJ45(n=72)Eq.y=39.8e4.3x y=1.03e4.29x y=0.17e4.98x RMSE51 1.340.28R20.940.930.96LYP9(n=72)Eq.y=16.9e5.1x y=0.30e5.54x y=0.09e5.68x RMSE178 4.18 1.13R20.670.700.80a Root mean squared error.respectively.All the feature parameters showed positive relation-ships,except for NRI,which displayed a negative one.An additional feature parameter CC was extracted from the seg-mented images,which is closely related to above-ground biomass, N content and LAI(Table5).The correlation coefficients of the other feature parameters extracted from a segmented image with rice plant indices varied to a various degree from those extracted from its intact one.Those of GMR,G/R and NGI extracted from a seg-mented image with above-ground biomass,N content and LAI were significantly lower than those from its intact ones,about49%,56% and63%lower for GMR,and14%,11%and16%lower for G/R,respec-tively.The correlation coefficients of NRI and H with the three plant indices increased somewhat after image segmentation.Those of H in particular increased sharply by232%,393%and223%,separately.Regression analysis between CC and rice plant indices of the three cultivars was done separately(Table5).CC showed good exponential relations with above-ground biomass,N content and LAI(Fig.3).Thefitting curve of LYP9deviated quite far from those of NJ46and NJ45,but the curves of NJ45and NJ46were quite close to each other,which is attributed to the difference in plant type between the two rice cultivars,hybrid indica rice LYP9vs.japonica rice NJ45and NJ46(Huang et al.,2008;Zong et al.,2000).4.Discussion4.1.Above-ground biomass,N content and LAI of differentcultivarsCultivar is a considerable factor in the difference of LAI.LYP9 was much bigger than NJ45and NJ46in LAI,mainly because LYP9 is a hybrid indica rice,with a loose shape,wide leaves and large mean tilt angle(Huang et al.,2008;Zong et al.,2000).These char-acteristics of LYP9were presented in the picture in a much bigger coverage than those of the other two cultivars.4.2.Relationships between image feature parameters and crop N statusAccuracy of the image captured with a digital camera is subject to the influence of changing climate factors,like illumination inten-sity(Graeff and Claupein,2003;Pagola et al.,2009).It has always been a challenge to measure colors in the natural environment.A color normally depends on the spectrum of the incident illumina-tion and the reflectance properties of the object surface,as well as potentially on the angles of illumination and viewing,and many other factors.Restoration of the color through a digital camera is also subject to the influences of the sensors,photometric system and processing system of the camera.Rorie et al.(2011)calibrated the pictures with the standard color card in photographing,but failed to compare the images before and after the calibration.It is,Y.Wang et al./Field Crops Research149(2013)33–3937Fig.2.Relationships of GMR(the difference between green channel and red channel)and G/R(greenness intensity divided by redness intensity)against(a and d)above-ground biomass,(b and e)nitrogen content and(c and f)leaf area index,respectively,for the rice cultivars Nanjing46(NJ46),Nanjing45(NJ45)and Liangyoupeijiu(LYP9),fitted with Eq.(5).therefore,hard to evaluate the accuracy of the image restored with this calibration method.Segmentation of images changed the correlation coefficients of feature parameters with above-ground biomass,N content and LAI to a varying degree.In the segmented images,correlation coefficients of GMR,G/R and NGI with above-ground biomass,N content and LAI were significantly reduced(Tables3and4),which was because in a segmented image,only the part of rice canopy stood out,making the color of the image simple,and in turn narrow-ing the variation ranges of parameters.In this case,the influences of climate factors,like illuminance,would be amplified.But on the contrary,in an intact image,the rice canopy was only a part of the image,the variation ranges of parameters were wider,and the calculation of parameters used the average of all pixels,thus per-mitting relatively larger errors and having a certain buffer capacity to influencing factors.Before the image segmentation,thefitting curves of the three cultivars for GMR and rice plant indices were quite close to each other(Fig.2).There was no significant difference between varieties,especially in the japonica and indica rice.Therefore,GMR would be a quite universal indicator applying to N diagnosis.But when it comes to the CC after image segmentation,thefitting curves of NJ45and NJ46were quite far from the LYP9(Fig.3),which is attributed to the different plant types between the two rice sub-species(Huang et al.,2008;Zong et al.,2000).For this reason,the use of CC to evaluate N status of japonica and indica rice needs different parameters.Canopy cover has an exponential relationship with above-ground biomass,N content and LAI(Li et al.,2010),which tallies with the actual growing process of rice.GMR,G/R and NGI extracted from the intact images are also in exponential relationship with the three plant indices(Fig.2),which is mainly because intact images contain two parts,rice canopy and soil,and the calcula-tion of parameters uses the average of all pixels in an image.As the canopy coverage increases,the proportion of the canopy in the whole image increases,and reflected in the feature parame-ters,thus making the feature parameters of the whole image closer to the mean value of the canopy area.As a result,GMR,G/R and NGI38Y.Wang et al./Field Crops Research149(2013)33–39Fig.3.Relationships of canopy cover(CC)against(a)above-ground biomass,(b)N content and(c)leaf area index for the rice cultivars Nanjing46(NJ46),Nanjing45 (NJ45)and Liangyoupeijiu(LYP9),fitted with Eq.(5).show a variaion trend the same as the CC does,and also similar to the senescence of plants,Adamsen et al.(1999)demonstrated with the G/R in the intact images.Although GMR,G/R and CC are well reflected the N status of rice, their application is subject to limitations.The CC ranges from0to 1theoretically.When the canopy of rice approaches full coverage, CC in the image would no longer increase,but the above-ground biomass,N content and LAI keep on increasing(Fig.3)and at this time CC will not truly reflect N status of the crop.GMR and G/R extracted from the intact images performed similarly to CC.When the parameters approach saturation(about30for GMR and1.4for G/R in Fig.2),the three plant indices of rice have not reached their maximum yet.Therefore,assessment of N status using these feature parameters can only be done before the canopy reaches saturation in coverage.The canopy,however,is far from saturation at thefinal top dressing,so it is still applicable in most cases.4.3.Image segmentation methodPrevious researchers did not pay attention to the research on how to segment images,and most of them adopted different meth-ods in image segmentation.Adamsen et al.(1999)did not perform any segmentation of images in their study on parameter G/R. Researches by Jia et al.(2009)and Kawashima and Nakatani(1998) used Photoshop manually to extract canopy images,which,though rather illustrative,is very time-consuming and may introduce man-made errors.Li et al.(2010)counted pixels with SAVI Green>0as canopy in the image,the image segmentation method is quick,but parameters in the equation need adjusting in light of images.On the basis of previous researches,this study puts forth a new method for segmenting images of rice canopy by setting threshold value based on the magnitude and distribution of GMR.This method is simple and easy to apply.It only needs a unified threshold value set for a group of images and is also very quick in data processing(less than1s to segment a15mega pixels image on a desktop com-puter,3.4GHz CPU).Moreover,this method is applicable to extract canopies of most other green plants.When the canopy coverage of a crop is quite high,the CC value extracted with this method is often slightly lower than the actual one(Fig.3),which is mainly because the lower part of the canopy is growing in the shade of the upper part,thus making the lower part darker in the image and lower in GMR value.When its GMR is low-ered below the threshold,this part will be regarded as background for deletion.Therefore,the extracted CC deviates somewhat from its actual value,but this deviation will not significantly affect the relationship of CC with crop N status.5.ConclusionsThe image segmentation method used in this study is simple in operation,rapid in data processing and also applicable to seg-ment canopies of other green plants.The feature parameters,either before or after image segmentation,are closely related to rice N sta-tus.GMR and G/R extracted from intact images and CC extracted from segmented images are all in exponential relationship with above-ground biomass,N content and LAI of rice(mean R2=0.83). However,the use of CC to evaluate N status of japonica and indica rice needs different parameters.The use of GMR,G/R and CC to diagnose N status of rice has to be done before the canopy reaches its saturation in coverage.Once the canopy gets saturated,these parameters no longer reflect the plant growth conditions accurately.However,the last fertilization of rice cultivation is typically done before earing stage,and the canopy is far from reaching its saturation in coverage at this time. AcknowledgmentsThis research was supported by the Knowledge Innovation Pro-gram of the Chinese Academy of Sciences(KSCX-YW-440)and the Agricultural Science and Technology Innovation Foundation of Jiangsu Province(CX(12)1002).We wish to thank the editor and two anonymous reviewers for their very helpful comments on ear-lier drafts.ReferencesAdamsen,F.J.,Pinter Jr.,P.J.,Barnes,E.M.,LaMorte,R.L.,Wall,G.W.,Leavitt,S.W., Kimball,B.A.,1999.Measuring wheat senescence with a digital camera.Crop Sci.39,719–724.。