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1.
Continuous paddy rice cultivation requires fields to be flooded most of the time limiting seriously the collection of detailed soil information. So far, no appropriate soil sensor technology for identifying soil variability of flooded fields has been reported. Therefore, the primary objective was the development of a sensing system that can float, acquire and process detailed geo-referenced soil information within flooded fields. An additional objective was to determine whether the collected apparent electrical conductivity (ECa) information could be used to support soil management at a within-field level. A floating sensing system (FloSSy) was built to record ECa using the electromagnetic induction sensor EM38, which does not require physical contact with the soil. Its feasibility was tested in an alluvial paddy field of 2.7 ha located in the Brahmaputra floodplain of Bangladesh. The high-resolution (1 × 1 m) ECa data were classified into three classes using the fuzzy k-means classification method. The variation among the classes could be attributed to differences in subsoil (0.15–0.30 m below soil surface) bulk density, with the smallest ECa values representing the lowest bulk density. This effect was attributed to differences in compaction of the plough pan due to differential puddling. There was also a significant difference in rice yield among the ECa classes, with the smallest ECa values representing the lowest yield. It was concluded that the floating sensing system allowed the collection of relevant soil information, opening potential for precision agriculture practices in flooded crop fields.  相似文献   

2.
为了促进蔬菜废弃物资源化还田,在室内模拟不同量[全量:每亩(667 m2)1.8 t,半量:每亩0.9 t]番茄秸秆和甘蓝叶残体还田,并设置添加菌剂(秸秆腐熟剂、农用酵素)和未添加菌剂处理,测定还田后7、14、21、28、35 d的土壤温度、pH、电导率、有机碳、养分含量以及腐殖质各组分含量,探究蔬菜废弃物还田量及配施菌剂对土壤理化性质和腐殖质组成的影响.结果 表明:各还田处理的土壤pH值呈先降低后增加趋势,其中配施菌剂处理的pH值变化幅度较小.蔬菜废弃物还田后7 d各处理的有机碳含量均迅速增加,增加范围为0.55~1.73 g·kg-1.与未施菌剂还田相比,还田35 d后番茄秸秆添加酵素全量还田处理的土壤全氮、碱解氮和速效钾含量分别增加了14.49%、9.30%和5.61%,甘蓝叶残体添加酵素全量还田处理的有效磷含量增幅最大,达到34.98%.在还田处理期间,番茄秸秆在第21 d的土壤水溶性物质含量达到最大,而甘蓝叶残体还田处理则是在第7 d上升到最大值,并且甘蓝叶残体各还田处理的土壤水溶性物质含量整体比番茄秸秆还田处理高.蔬菜废弃物配施酵素全量还田能够有效促进土壤腐殖质和胡敏酸含量增加,且两种蔬菜废弃物还田处理的土壤腐殖化程度均在还田第7d达到最大.综合比较而言,蔬菜废弃物配施酵素全量还田在提高秸秆资源化利用效率、降低还田成本方面效果最佳,更适宜推广应用.  相似文献   

3.
受污染农田修复技术应用效果的综合评价,在当前我国土壤污染管控与修复工作中尤为重要和紧迫。本文针对自主研发的改良剂,在我国华南地区受镉(Cd)污染的水稻种植区开展野外大田试验,重点围绕土壤环境、肥力和健康质量的变化,探索改良剂施用对土壤质量的影响;选择DTPA浸提态Cd、有机质、碱解氮、有效磷、速效钾、阳离子交换量(CEC)、糙米Cd和稻谷产量构建指标体系,利用动态加权综合评价模型评判改良剂的修复效果。结果表明,当改良剂施用量为6 000 kg·hm-2和7 500 kg·hm-2时,DTPA浸提态Cd含量分别减少10.5%和8.8%。当改良剂用量为6 000 kg·hm-2时,有机质含量减小6.3%;改良剂没有显著影响碱解氮、有效磷和CEC含量,但是显著提高了速效钾含量。当改良剂用量为1 500 kg·hm-2时,糙米Cd含量增加23.9%;当改良剂用量≥4 500 kg·hm-2时,糙米Cd含量显著低于国家标准,且修复效率(RE)均超过40%。当改良剂用量为4 500 kg·hm-2时,稻谷产量增加18.7%。采用动态加权综合评价模型研究发现,当用量为6 000 kg·hm-2时,改良剂修复Cd污染稻田的综合效果最佳。  相似文献   

4.
This study examined the effect of different negative pressures and soil textures on water and salt movement to improve the efficiency of negative pressure irrigation(NPI).Four soil textures of varying fineness(Loamy Sand,Loam,Silty Loam,and Sandy Loam) and three negative pressure values(0,-5,and-10 kPa) were used.As irrigation time increased,wetting front movement speeds decreased,and as negative pressure increased,wetting front size decreased.Coarse soils had the smallest wetting front under greater negative pressure.Next,water infiltration rate decreased as irrigation time increased,and coarse soils had the lowest average infiltration rate under greater negative pressure.Finally,salt content increased with distance from the irrigation emitter and with increased negative pressure.Further,coarse soils were found to have decreased desalination under greater negative pressure.Thus,soil texture has a strong effect on NPI efficiency.However,by adjusting pressure values in accordance with soil texture,soil water content can be controlled and maintained.These findings are important to the improvement of NPI systems,increasing their practicality for agricultural use.  相似文献   

5.
为构建稻田有机肥配施的土壤环境效应评价指标体系,采用整合分析筛选了稻田有机肥配施的土壤环境敏感因子,进一步通过变异分析、相关分析、主成分分析以及随机森林模型的耦合分析构建了稻田有机肥配施的土壤环境效应评价指标体系.整合分析从43个土壤环境指标中筛选出了26个有机肥配施的土壤环境敏感因子,包括稻田土壤容重(BD)、非毛管孔隙度、团聚体(>5、2~5、1~2、0.5~1、0.25~0.5 mm)、<0.25 mm微团聚体、pH、电导率(EC)、交换性钾离子、有机碳(SOC)、总氮(TN)、总磷(TP)、总钾(TK)、速效氮(AN)、速效磷(AP)、速效钾(AK)、土壤微生物量碳(MBC)、土壤微生物量氮(MBN)、土壤脲酶(SUE)活性、土壤转化酶(SSC)活性、土壤脱氢酶(SDH)活性、锌(Zn)、铜(Cu)、镉(Cd).对环境敏感因子进行变异分析,筛选出累计贡献率大于85%的环境敏感因子,进一步对筛选到的环境敏感因子进行相关性分析得出因子之间的相关性,通过主成分分析对因子进行分组,通过随机森林分析得出因子重要性,最后通过三者的耦合分析构建了包括BD、pH、EC、SOC、TN、AK、AP、MBC、Cd和Cu等10个指标的稻田有机肥配施的土壤环境效应评价指标体系.本研究为稻田有机肥配施的土壤环境效应评价奠定了基础,为我国土壤环境评价指标体系的构建提供了新思路.  相似文献   

6.
不同地力玉米田土壤有机碳矿化特征   总被引:2,自引:1,他引:2  
为探讨不同地力玉米田土壤有机碳矿化特征,通过为期196 d的土壤有机碳矿化培养试验,对高、中、低3种不同地力玉米田0~20 cm和20~40 cm土层土壤进行了研究。结果表明:不同地力玉米田土壤有机碳矿化速率随时间的变化呈现相同的变化趋势,即随培养时间延长,呈现先高后低的变化趋势,最后趋于平稳;但随地力等级的降低,土壤有机碳矿化速率逐渐减小。培养结束时,不同地力玉米田0~20 cm和20~40 cm土层土壤有机碳累积矿化量之间均存在显著性差异(P0.05);低地力土壤有机碳稳定性最差,固存量最小。同一地力,20~40 cm土层土壤有机碳矿化速率和累积矿化量较0~20 cm显著降低(P0.05),表层土壤稳定性较差,不利于土壤有机碳固定。伴随土壤有机碳矿化过程,土壤微生物生物量碳(MBC)和土壤可溶性有机碳(DOC)含量均较初始含量显著降低(P0.05);土壤有机碳潜在矿化势(Cp)与土壤有机碳、全氮、铵态氮、硝态氮、MBC和DOC均呈极显著正相关。土壤有机碳矿化是陆地生态系统碳循环的重要过程,且当地力等级变化时,各土层土壤有机碳的稳定性均受到不同程度的影响。  相似文献   

7.
针对河北省黑龙港区轻壤质和砂壤质土壤分布较多、氮肥施用方式不合理、氮肥效率低等问题,本研究采用田间试验法,在轻壤和砂壤质麦田同时设置不同氮肥基追比处理,探讨小麦旗叶SPAD值动态变化、叶绿素荧光参数和叶面积指数,以及成熟期植株全氮、干物质、产量、氮素效率等。结果表明:轻壤质小麦开花前后SPAD值、叶绿素荧光和叶面积指数均以氮肥基追比4∶6较好,砂壤质则为3∶7较好;灌浆期轻壤质和砂壤质各处理叶片叶绿素荧光参数和叶面积指数变化相近。2种质地土壤下小麦籽粒全氮积累量远大于秸秆,轻壤质植株干物质、全氮含量和产量高于砂壤质,且轻壤质氮肥基追比4∶6处理植株全氮较砂壤质提高32.8%,轻壤质小麦最高产量较砂壤质增加41.4%。小麦植株氮素积累量、氮肥偏生产力、氮肥农学效率、氮肥表观回收率等轻壤质均以4∶6处理最高,砂壤质则以3∶7最优。因此,轻壤质土壤小麦高产潜力强于砂壤质,两者合理氮肥基追比分别为4∶6和3∶7,生产上应该针对不同质地土壤类型特点进行分类指导合理分配氮肥。  相似文献   

8.
With increased cultivation of transgenic Bacillus thuringiensis(Bt) cotton in the saline alkaline soil of China, assessments of transgenic crop biosafety have focused on the effects of soil salinity on rhizosphere microbes and Bt protein residues. In 2013 and 2014, investigations were conducted on the rhizosphere microbial biomass, soil enzyme activities and Bt protein contents of the soil under transgenic Bt cotton(variety GK19) and its parental non-transgenic cotton(Simian 3) cultivated at various salinity levels(1.15, 6.00 and 11.46 dS m~(-1)). Under soil salinity stress, trace amounts of Bt proteins were observed in the Bt cotton GK19 rhizosphere soil, although the protein content increased with cotton growth and increased soil salinity levels. The populations of slight halophilic bacteria, phosphate solubilizing bacteria, ammonifying bacteria, nitrifying bacteria and denitrifying bacteria decreased with increased soil salinity in the Bt and non-Bt cotton rhizosphere soil, and the microbial biomass carbon, microbial respiration and soil catalase, urease and alkaline phosphatase activity also decreased. Correlation analyses showed that the increased Bt protein content in the Bt cotton rhizosphere soil may have been caused by the slower decomposition of soil microorganisms, which suggests that salinity was the main factor influencing the relevant activities of the soil microorganisms and indicates that Bt proteins had no clear adverse effects on the soil microorganisms. The results of this study may provide a theoretical basis for risk assessments of genetically modified cotton in saline alkaline soil.  相似文献   

9.
为探讨黑龙江省半干旱地区不同质地黑土的净氮转化速率和温室气体排放规律,以壤砂土和粉壤土为研究对象开展室内培养试验,对土壤净硝化速率和净矿化速率、N2O和CO2排放速率与累积排放量进行研究。结果表明:7d培养期间壤砂土的平均净矿化速率和CO2平均排放速率分别为0.49mgN kg-1 d-1和0.30mgCO2-C kg-1 h-1,显著低于粉壤土的平均净矿化速率(1.37 mgN kg-1 d-1)和CO2平均排放速率(0.47mgCO2-C kg-1 h-1)。壤砂土的平均净硝化速率和N2O平均排放速率分别为1.65mgN kg-1 d-1和212.6ngN2O-N kg-1 h-1,显著低于粉壤土的5.02mgN kg-1 d-1和521.3ngN2O-N kg-1 h-1。壤砂土和粉壤土的N2O排放比率分别为0.081%~0.301%和0.210%~0.254%。研究表明,土壤质地显著影响土壤净氮转化速率和温室气体排放,壤砂土较低的pH、有机碳和水溶性有机碳含量是导致其净硝化速率、净矿化速率以及N2O、CO2排放速率显著低于粉壤土的主要原因。  相似文献   

10.
【目的】探索不同土壤类型对烤烟烟叶质体色素及其降解产物含量的影响,为选择合适的土壤类型以及有针对性地改善土壤状况提供参考。【方法】2010年在吉林延边地区选择暗棕壤、黑砂土、白浆土等3种土壤为研究对象,以当地主栽烟草品种“吉烟9号”为试材,研究不同土壤类型对烟叶质体色素及其降解产物的影响。【结果】土壤条件对烤烟烟叶质体色素及其降解产物均有不同程度的影响。暗棕壤土质条件下,烟叶的叶绿素含量(42.58 μg/g)、类胡萝卜素含量(265.17 μg/g)及类胡萝卜素降解产物总量(32.15 μg/g)均最高,新植二烯含量(526.44 μg/g)稍低于黑砂土条件下烟叶;黑砂土条件下烟叶中的新植二烯含量最高(540.78 μg/g),其他质体色素和香气物质总量均处于3种土壤的中间水平;白浆土条件下质体色素含量及其降解产物均处于较低水平。【结论】暗棕壤土质更有利于烟叶香气物质的生成,且各香气成分含量较为协调。  相似文献   

11.
连作植烟土壤中酚酸物质与土壤因子的关系分析   总被引:3,自引:0,他引:3  
为初步探明连作土壤中酚酸类物质与土壤主要因子的相互关系,以同一植烟区域不同种植年限土壤(1、6、8、14、16 a)为对象,分析不同连作年限植烟土壤酚酸类物质的种类、含量,以及土壤理化性状和酶活性的变化,在相关性分析的基础上,利用逐步回归模型,探讨酚酸类物质与土壤理化性状和酶活性的相互关系。结果表明,连作导致土壤中酚酸类物质积累、植烟土壤酸化和养分失衡。逐步回归分析表明:间苯三酚对pH存在抑制作用,肉桂酸对过氧化氢酶活性存在促进作用,阔马酸对脲酶活性存在抑制作用;间苯三酚、阔马酸和酚酸类物质总量均受到脲酶的抑制作用,对羟基苯甲酸和肉桂酸分别受过氧化氢酶的抑制和促进作用;阿魏酸受脲酶、过氧化氢酶的抑制作用和蔗糖酶的促进作用;间苯三酚、对羟基苯甲酸和酚酸类物质总含量均受土壤pH的抑制作用。  相似文献   

12.
等高植物篱笆条件下红壤坡耕地水土流失的发生特征   总被引:10,自引:0,他引:10       下载免费PDF全文
研究了红壤坡耕地植物篱笆条件下的水土流失特征、土壤入渗特性及径流量、侵蚀量、侵蚀雨量、降雨量、入渗量的发生特征.结果表明,与大豆单作相比,黄花菜(Hemerocallis citrirna Baroni)和百喜草(Paspalum. notatum Flugge)植物篱笆的径流量和侵蚀量分别减少10.14~11.56倍和135.34~165.84倍;植物篱笆处理和大豆单作处理的径流量、侵蚀量与可产生侵蚀的降雨量之间呈极显著正相关,建立了相应的降雨产流、降雨产沙、径流侵蚀回归模型,同时建立了降雨入渗、入渗产流、入渗侵蚀的回归模型.植物篱笆水土保持的本质原因是植物篱笆地下部根系显著改善了耕层土壤的物理性状;显著增强了土壤的入渗能力,植物篱笆带能在较长的时间内维持较高的土壤入渗量和较大的稳定入渗速率.  相似文献   

13.
As the organic food sector has grownand changed to become more mainstream, large-scaleconventional growers have entered into organicproduction. While it is increasingly clear that notall organic farms are self-sufficient small scaleunits that practice poly-cultural agronomy and sell inlocal marketing venues, there still exists apresumption that there are clear lines between thesmall scale ``movement' farmers who followagro-ecological agronomic ideals and the relativelylarger and partly conventional newcomers who do not.This paper addresses a specific empirical issue, whichis the extent to which California organic farmerspractice the techniques of ecological farming. Itillustrates that while there are some distinctdifferences in practices between larger and/orpart-conventional (i.e., mixed) growers and smallerand/or all-organic growers, it also shows that inalmost all cases, practices fall quite short ofagro-ecological ideals. By examining in more depth howgrowers follow particular agro-ecological principles,the paper also demonstrates that key variations arerelated to variables separate from scale. Some ofthese variables are geographic, ranging frombiophysical and climatic opportunities andconstraints, to regional norms and institutionalsupport. Mostly, however, variation is related to cropspecificities and the availability of efficacioustechnologies to deal with crop-specific problems. Thisso-called technology barrier crucially depends on howorganic is defined, and thus suggests the importanceof organic rules and regulations in shaping thepractices of organic production.  相似文献   

14.
[目的]明确土壤耕层重构技术对棉田杂草的防治效果,探索新的棉田杂草防治途径。[方法]采用盆栽模拟试验与大田对比试验,调查旋耕+除草剂、土壤耕层重构对杂草种类与数量的影响。[结果]盆栽试验结果显示,处理后20d与55d对照杂草种类分别为6种与9种,总鲜重为每盆83.5g与678.1g;旋耕+除草剂处理杂草种类分别为3种与9种,总鲜重为4.9g与452.9g,其中处理20d后均为阔叶杂草,处理55d后阔叶杂草鲜重与对照差异不显著,单子叶杂草鲜重显著低于对照;耕层重构处理2次调查均未发现杂草。大田试验结果中,苗期、初花期与收获期对照杂草种类分别为4种、6种与8种,鲜重分别为104.4g·m~(-2)、404.9g·m~(-2)、752.9g·m~(-2),苗期以阔叶杂草为主,初花期与收获期单子叶杂草增多;耕层重构处理3次调查均仅发现微量杂草。[结论]以上结果表明,旋耕+除草剂对棉花苗期的禾本科杂草与部分阔叶杂草有一定的防治效果,随着时间延长,杂草防治效果逐渐降低,而土壤耕层重构处理对所有棉田杂草具有一次性彻底灭除效果,减少除草剂污染,节省用工。土壤耕层重构是一种棉田杂草防治的新途径。  相似文献   

15.
本研究选取太湖流域黄泥土长期定位试验田作为研究对象,明确40 a长期施磷对水稻土土壤磷库、磷形态及有效性的影响。结果表明:长期施磷(NPK)处理的土壤总磷和有效磷含量高达589.58 mg·kg-1和51.67 mg·kg-1,比不施磷(NK)处理显著增加126.61%和216.41%。两处理无机磷均以Fe-P和Ca-P为主,约占无机磷的69.53%~79.86%,有机磷以活性和中活性有机磷为主。长期施磷使稻田无机磷含量在3个生育期均极显著增加,增幅为170%以上,其中Al-P和Fe-P的含量及相对占比显著提升,Ca-P含量增加但相对含量明显降低,O-P含量变化较小而相对含量降低。长期施磷处理下有机磷含量仅在分蘖期增幅显著(33%),主要表现为活性和中活性有机磷含量显著增加。与分蘖期相比,抽穗期长期施磷处理的Al-P、Fe-P以及高稳定有机磷的相对含量明显下降,Ca-P和中活性有机磷的相对含量上升,而长期不施磷处理表现为Fe-P、O-P以及高稳定有机磷的相对含量下降,Ca-P和中活性有机磷的相对含量上升。Al-P、Fe-P、Ca-P、O-P和中活性有机磷均与有效磷(AP)显著正相关。研究发现: Al-P、Fe-P和Ca-P是黄泥土稻田最主要的有效磷源,土壤缺磷时土壤磷酸酶等对有机磷的活化也是重要的有效磷来源之一;长期施用无机磷肥导致稻田土壤无机磷库累积明显,磷流失风险增加,因此应在保证稻麦高产的前提下合理降低磷肥施入量,充分活化利用土壤中固存的难溶态磷来提高土壤磷素利用率。  相似文献   

16.
Spatial sampling designs used to characterize the spatial variability of soil attributes are crucial for science studies. Sample planning for the interpolation of a regionalized variable may use several criteria, which could be best selected from an estimated semivariogram from a previously established grid. The objective of this study was to optimize the procedure for scaled semivariogram use to plan soil sampling in sugarcane fields in the Alfisol and Oxisol regions of Jaboticabal Town in S?o Paulo State, Brazil. A scaled semivariogram for several soil chemical attributes was estimated from the data obtained from two grids positioned on a sugarcane field area, sampled at a depth of 0.0?C0.5?m. The research showed that regular grids with uniform intervals did not express the real spatial variability of the soil attributes of Oxisols and Alfisols in the study area. The calculated final sampling density based on the scaled parameters of the semivariogram was one sample for each 2?ha in Area 1 (convex landscape) and one sample for each 1?ha in Area 2 (linear landscape), as indicated by SANOS 0.1 software. The combined use of the simulation programs and scaled semivariograms can be used to define sampling points. These results may help in soil fertility mapping and thereby improve nutrient management in sugarcane crops.  相似文献   

17.
赤红壤蔗地土壤酸缓冲性能与调控研究   总被引:2,自引:0,他引:2  
采用酸滴定土壤酸度的方法研究广西蔗地土壤对酸的缓冲性能,结果表明,广西赤红壤蔗地土壤酸缓冲能力不强且对酸敏感,其土壤酸化转折点在加入模拟酸雨pH值3.0-3.5之间。酸雨会造成蔗地土壤严重酸化,而年施用75t/hm2酒精废液对蔗地土壤酸化影响较小。影响土壤酸缓冲性能因素主要为有机质、物理性粘粒、盐基总量和交换钙。据此可采取增施有机肥,施用碱性物质如石灰或碱性肥料如钙镁磷肥,以及增加土壤覆盖如蔗叶还田,或采取等高种植等措施,增加土壤有机质和交换性阳离子含量,减少土壤粘粒及阳离子流失,降低土壤酸度,从而提高蔗地土壤酸缓冲能力,改善蔗地土壤生态环境。  相似文献   

18.
基于河北省石家庄市郊农田的土壤分布状况,以土属为评价单元研究区域内的土壤质量状况,选取影响土壤质量的地形坡度、成土母质类型、有效土层厚度和质地等主要分类指标,采用经验法和模糊隶属函数,定量地分析了该地区不同土属类型土壤的质量指数(IFI)。结果显示,石家庄市不同土属的土壤质量差异比较明显:①洪冲积砂壤质潮褐土、洪冲积壤质潮褐土、洪冲积砂砾质潮褐土、黄土质石灰性褐土、洪冲积壤质石灰性褐土、灰砂质潮土、夹黏灰性砂质潮土、灰性壤质潮土、灰性砂壤质潮土、灰性夹黏壤质潮土、灰性夹黏砂壤质潮土、氯化物盐化潮土、硫酸盐盐化潮土、砾砂质冲积土、砂质冲积土的IFI值分别为0.868、0.884、0.847、0.702、0.809、0.776、0.816、0.862、0.846、0.902、0.843、0.783、0.794、0.830、0.831,土壤质量较好,适宜耕种;其中,灰砂质潮土、氯化物盐化潮土、砾砂质冲积土、砂质冲积土由于黏粒含量均<10%,因此耕种前需人工改良。②灰黏壤质草甸沼泽土、固定草甸风沙土、半固定草甸风沙土的IFI值分别为0.822、0.783、0.626,土壤质量较好,但是易受到人为破坏,不应农用,建议种...  相似文献   

19.
土壤肥力质量评价的研究进展   总被引:15,自引:0,他引:15  
阐述了土壤质量和土壤肥力质量的最新概念,论述了土壤肥力质量的评价指标体系与评价方法,对近年来国内外有关土壤肥力质量评价的最新研究资料进行了综述,为进一步开展该领域的深入研究以及土壤资源的合理利用提供了参考.  相似文献   

20.
为合理使用氮肥,维持稻田生态健康发展,运用磷脂脂肪酸(PLFA)和Biolog-Eco微平板法研究了4种氮肥管理模式:不施氮肥(CK)、农民习惯施肥(FP)、氮肥优化管理1(OPT1)、氮肥优化管理2(OPT2)对稻田土壤微生物群落结构的影响。结果表明:OPT1处理较CK提高了土壤微生物的代谢活性和碳源利用能力,而FP、OPT2处理均较CK降低了土壤微生物代谢活性和碳源利用能力。OPT1处理的土壤总生物量最高,为42.11 nmol·g-1,OPT2处理的土壤总生物量为40.16 nmol·g-1,均高于CK的34.19 nmol·g-1,而FP处理的土壤总生物量为34.16 nmol·g-1,低于CK。OPT1处理的土壤微生物多样性较复杂,F/B值最高。综合各项指标,OPT1处理更有利于土壤生态环境稳定。  相似文献   

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