Integration of Multiple Spectral Data via a Logistic Regression Algorithm for Detection of Crop Residue Burned Areas:A Case Study of Songnen Plain,Northeast China

The burning of crop residues in fields is a significant global biomass burning activity which is a key element of the terrestrial carbon cycle,and an important source of atmospheric trace gasses and aerosols.Accurate estimation of cropland burned area is both crucial and challenging,especially for the small and fragmented burned scars in China.Here we developed an automated burned area mapping algorithm that was implemented using Sentinel-2 Multi Spectral Instrument(MSI)data and its effectiveness was tested taking Songnen Plain,Northeast China as a case using satellite image of 2020.We employed a logistic regression method for integrating multiple spectral data into a synthetic indicator,and compared the results with manually interpreted burned area reference maps and the Moderate-Resolution Imaging Spectroradiometer(MODIS)MCD64A1 burned area product.The overall accuracy of the single variable logistic regression was 77.38%to 86.90%and 73.47%to 97.14%for the 52TCQ and 51TYM cases,respectively.In comparison,the accuracy of the burned area map was improved to 87.14%and 98.33%for the 52TCQ and 51TYM cases,respectively by multiple variable logistic regression of Sentind-2 images.The balance of omission error and commission error was also improved.The integration of multiple spectral data combined with a logistic regression method proves to be effective for burned area detection,offering a highly automated process with an automatic threshold determination mechanism.This method exhibits excellent extensibility and flexibility taking the image tile as the operating unit.It is suitable for burned area detection at a regional scale and can also be implemented with other satellite data.

Changes in groundwater resources and their influencing factors in Songnen Plain, China

The Songnen Plain is a crucial agricultural area in China,and in the past 20 years,a large number of dry fields have been developed into paddy fields in order to improve land output efficiency.As a result,the effective irrigation area of agriculture has increased annually,and the conversion mode and quantity between surface water and groundwater have changed considerably.It is essential to identify the changes in groundwater resources and their influencing factors for the sustainable development of economy and society.This study evaluates groundwater resources in the Songnen Plain using the water balance method based on meteorological,hydrological and groundwater monitoring data from 2000 to 2020.The results 3 show that the groundwater resources in the region amount to 15.945 billion m with precipitation infiltration being the most important component,accounting for 73.09%,which is followed surface water irrigation infiltration and river and ditch infiltration,constituting 14.55%and 10.32%,respectively.Different factors influence groundwater resources in different periods.Compared to 1985,the increase of surface water irrigation infiltration is the primary factor responsible for the increase of groundwater resources,while other recharge sources have decreased during the same period.Compared to 2005,all groundwater resources have increased,with the increase of surface water irrigation infiltration and river channel infiltration being the primary factors.

Neoarchean Magmatic Events in the Western Songnen Massif,Central Asian Orogenic Belt:Timing and Tectonic Significance

Whether a Neoarchean basement existing in the Songnen massif is currently debated.Identification of Archean magmatism from the Songnen Massif is helpful to resolve this issue.Here,we report newly discovered Neoarchean Shanquan pluton in the Western Songnen Massif.These Neoarchean Shanquan pluton are mainly composed of granites that are exposed near the town of Shanquan in Heilongjiang Province.LA-ICP-MS zircon U-Pb dating reveals that the sample 2015TW1 has an upper intercept age of 2801±69 Ma and a weighted mean age of 2708±18 Ma,while samples LJ27QY1 and LJ27QY2 have upper intercept ages of 2677±57 Ma and 2653±18 Ma,and weighted mean ages of 2649±10 Ma and 2653±15 Ma,respectively.This indicates that these granites were formed at~2.7 Ga.Most of the~2.7 Ga zircons have older TDM2 ages of 2762–3326 Ma with positiveεHf(t)values ranging from 0 to 6.4,while a few of the zircons have negativeεHf(t)values ranging from-8.1 to-11.5 and older TDM2 ages varying from 3158 to 3264 Ma.The zircon Hf isotopes indicate that Paleo-Mesoarchean crusts might once existed in the Songnen Massif,and the studied Neoarchean magmas were principally derived from partial melting of these Paleo-Mesoarchean ancient crust.Based on the geochronological spectrum of magmatic and detrital zircons,the Songnen,Erguna,Jiamusi,Bureya massifs may have a common basement prior to the Neoproterozoic and may even be linked with the Triam Craton.

Effects of Groundwater with Various Salinities on Evaporation and Redistribution of Water and Salt in Saline-sodic Soils in Songnen Plain,Northeast China

Groundwater mineralization is one of the main factors affecting the transport of soil water and salt in saline-sodic areas.To investigate the effects of groundwater with different levels of salinity on evaporation and distributions of soil water and salt in Songnen Plain,Northeast China,five levels of groundwater sodium adsorption ration of water(SARw)and total salt content(TSC mmol/L)were conducted in an oil column lysimeters.The five treated groundwater labeled as ST0:0,ST0:10,ST5:40,ST10:70 and ST20:100,were prepared with NaCl and CaCl2 in proportion,respectively.The results showed the groundwater evaporation(GWE)and soil evaporation(SE)increased firstly and then decreased with the increase of groundwater salinity.The values of GWE and SE in ST10:70 treatment were the highest,which were 2.09 and 1.84 times the values in the ST0:0 treatment with the lowest GWE and SE.There was a positive linear correlation between GWE and the Ca^(2+)content in groundwater,with R^(2)=0.998.The soil water content(SWC)of ST0:0 treatment was significantly(P<0.05)less than those of other treatments during the test.The SWC of the ST0:0 and ST0:10 treatments increased with the increase of soil depth,while the other treatments showed the opposite trend.Statistical analysis indicated the SWC in the 0–60 cm soil layer was positively correlated with the groundwater TSC and its ion contents during the test.Salt accumulation occurred in the topsoil and the salt accumulation in the 0–20 cm soil layer was significantly(P<0.05)greater than that in the subsoil.This study revealed the effects of the salinity level of groundwater,especially the Ca^(2+)content and TSC of groundwater,on the GWE and distributions of soil water and salt,which provided important support for the prevention and reclamation of soil salinization and sodificaton in shallow groundwater regions.

松嫩平原环境演变及其对地下水资源影响

松嫩平原是中国重要的农业区,近代以来原始的森林草原生态系统被改造为以旱田为主,少量的湿地和草原并存在的生态结构。近20年来,为了提高土地产出效率,大量湿地和旱田被开发成水田,生态结构又产生了较大变化。在气候条件和生态结构的动态变化过程中,地表水与地下水的转换方式和转换量发生了较大变化,对地下水资源产生了显著影响。笔者等采用水量平衡法评价松嫩平原2000~2020年地下水资源为159.45亿m^(3).

基于地球物理数据融合的大兴安岭中段东缘地壳结构研究

位于中亚造山带东段的兴安地块和松辽锡林浩特地块被晚古生代贺根山-黑河缝合带分开。随后,大兴安岭与松辽盆地被中新生代嫩江-八里罕断裂分开。在大兴安岭中段,这两构造带的位置及板块拼合时间尚不明确。为研究大兴安岭中段东缘重要构造断裂、构造单元及结晶基底属性特征,在扎兰屯-阿荣旗地区采集处理一条长60 km的重力、磁法和大地电磁数据,重新处理了1:20万扎兰屯幅、阿荣旗幅区域布格重力异常数据。通过多种地球物理数据融合,解译了7条重要断裂,其中庞家街断裂和红星断裂是控制贺根山-黑河缝合带的深大断裂。北西向阿伦河断裂为深大断裂,至少切割到中地壳。发现了两个中地壳低阻带,其中C2异常解释为贺根山-黑河缝合带。通过1:25万阿荣旗幅地质填图资料,证实了地球物理数据融合的推断结果,为大兴安岭中段东缘构造带演化研究提供了重要支撑。

生物炭对松嫩平原盐碱土玉米生长、养分积累及产量的影响

为了探索生物炭施用量对盐碱化土壤种植玉米的效果,进行了田间小区试验,研究了生物炭不同施用量(0,10,20,40和80 t·hm^(-2))对玉米生长、养分积累及产量的影响。结果表明,生物炭增加了花后干物质积累量,促进了籽粒灌浆速率,提升了玉米植株及籽粒对养分(C、N、P、K)的吸收,进而提高了玉米产量,改善了玉米品质。因此,在松嫩平原西部碱化玉米田上生物炭施用量40 t·hm^(-2)时玉米植株叶茎鞘养分积累最为充足,籽粒灌浆活跃期长,玉米产量最高,为最经济有效的用量。

苏打盐碱地稻米品质研究进展与展望

水稻是苏打盐碱地改良的先锋作物,稻米品质是水稻特征的重要指标。当前研究多关注盐碱地治理及水稻产量,有关盐碱胁迫下稻米品质的研究相对较少。本文从稻米的加工、外观、营养及感官食味品质4个方面系统梳理了苏打盐碱地条件下稻米品质特征,并总结苏打盐碱地水稻品种以及典型改良及栽培措施对稻米品质的影响。研究发现,苏打盐碱地条件下,稻米品质整体表现为较低的整精米率、精米率、糙米率及直链淀粉含量,较高的垩白粒率、垩白度及高蛋白质含量的特点,具有糙米蛋白含量高(更高的营养价值)、半透明颗粒少、淀粉低、钠等金属离子含量高等优点。研究提出未来需要进一步探讨苏打盐碱地条件下水稻品质形成、优异种质资源挖掘、产量与品质的协同提升,以期为苏打盐碱地水稻食味品质提升与特色品质的挖掘提供理论与实践参考。

松嫩盐碱退化草地土壤理化性质及离子变化规律分析

为了解不同盐碱退化状态下土壤理化性质和土壤离子的变化,本研究以松嫩温性草甸草地为研究对象,比较了未退化、轻度、中度和重度盐碱退化草地下土壤离子和土壤理化性质,分析盐碱退化过程中土壤理化性质、离子变化规律及其相互关系。结果表明:土壤K^(+)、Na^(+)、Mg^(2^+)、Ca ^(2+)、Cl^(-)、HCO_(3)^(-)、SO_(4)^(2-)、CO_(3)^( 2-)随盐碱程度加重显著增加,阳离子交换量显著下降(P<0.05)。随着盐碱程度变化,土壤电导率、pH、全钾显著增加,土壤全氮、碱解氮显著下降(P<0.05)。与未退化土壤相比,轻度和中度盐碱草地土壤含水量显著上升(P<0.05),速效磷含量显著降低(P<0.05);重度退化盐碱草地速效磷含量显著上升(P<0.05)。土壤TN、AN、AP、K^(+)与盐碱化程度之间存在显著的相关性。未退化草地土壤AN、TN含量较高,而重度退化草地AP、K^(+)含量较高。本研究为松嫩盐碱退化草地修复措施的合理选择提供依据。

施氮对松嫩平原栽培羊草地生产性能和土壤养分的影响

为明确施氮对栽培草地生产性能及土壤养分的影响,本研究以栽培羊草(Leymus chinensis)地为研究对象,采用随机区组设计,设置不同施氮处理[N0(0 kg·hm^(-2))、N1 (42 kg·hm^(-2))、N2(84 kg·hm^(-2))、N3(126 kg·hm^(-2))],通过连续两年(2018年、2019年)试验观测,分析不同施氮水平下栽培羊草地的株高、干物质产量及土壤p H、有机质、全氮、碱解氮、全磷和速效磷变化特征。结果表明,施氮后羊草的株高和干物质产量随施氮量的增加呈先增加后减小的变化趋势,在施氮量为84 kg·hm^(-2)(N2处理)时表现最好,随后呈下降趋势。2018年和2019年,在N2处理下羊草的干物质产量较N0分别提高了43.20%(P <0.05)和22.15%。与N0相比,N2处理显著提高了2019年0-10 cm土壤全氮和全磷含量,但对p H影响不显著。相关分析表明,羊草的株高、干物质产量与土壤全磷、速效磷和有机质含量呈显著正相关关系(P <0.05),与土壤p H呈极显著负相关关系(P <0.01)。综合分析,当氮肥施用量为84 kg·hm^(-2)时,对松嫩平原栽培羊草地的羊草生产和土壤肥力改善效果最好。

松嫩沙地元素和Sr-Nd同位素组成特征及其对区域粉尘物源的指示

松嫩沙地位于欧亚黄土带最东端,其物质组成的研究有利于重建松嫩平原冰期—间冰期粉尘传输路径。为此,系统采集了松嫩沙地123个河流沙和风成沙样品,对其进行分粒级的常量、微量和稀土元素以及Sr-Nd同位素组成等地球化学分析,并利用Frequentist模型进行风尘物源定量重建,探讨松嫩沙地不同区域、不同粒级组分对哈尔滨黄土的贡献及搬运路径。结果表明,松嫩沙地经历了初级的化学风化过程(<63μm、<30μm、<10μm组分CIA平均值分别为55.20、57.46、57.51),有较低的再循环历史(<63μm、<30μm、<10μm组分CIA/WIP比值的平均值为0.98、1.08、1.04)。根据不同粒度组分的元素地球化学与Sr-Nd同位素组成特征,将松嫩沙地划分为西北部和西南部两个地球化学分区。不同粒度组分地球化学组成的定量重建结果表明,这两个分区不同粒级组分(<63μm、<30μm、<10μm)对哈尔滨黄土的贡献度分别为:75.7%~88.5%、73.4%~84.9%、61.0%~89.7%(西南部)和11.5%~24.3%、15.1%~26.6%、10.3%~39%(西北部)。本研究揭示了末次冰期以来松嫩平原粉尘传输路径以西南方向为主,与冰期以西北风为主导的环流模式存在差异。

松嫩平原黑土区畜禽粪肥质量评价

明确松嫩平原黑土区畜禽粪肥品质差异,可为其质量提升及合理施用提供理论依据。本研究于黑龙江省松嫩平原黑土区采集猪粪、牛粪、羊粪和鸡粪4种堆肥样品67个,通过测定不同种类畜禽粪肥技术指标、限量指标及有机组分含量,建立畜禽粪肥质量综合得分模型,从而对其质量进行评价。结果表明:(1)猪粪肥、牛粪肥、羊粪肥和鸡粪肥的平均种子发芽指数(GI)分别为44.1%、57.0%、51.9%和41.4%,均接近或大于50%的畜禽粪肥无害化要求,但小于有机肥NY/T525-2021标准70%的要求;(2)4种畜禽粪肥中,牛粪肥各项指标都更接近于NY/T525-2021标准要求,且牛粪肥中较活跃的有机组分可溶性有机质(DOM)、可提取腐殖酸(HE)、胡敏酸(HA)、富里酸(FA)含量均高于其他3种;(3)在畜禽粪肥质量评价综合得分模型中,牛粪肥获得最高得分0.834,其它粪肥得分依次为:羊粪肥0.761、猪粪肥0.732、鸡粪肥0.508。总体来看,4种畜禽粪肥的腐熟度仍需进一步提高,其综合质量排序为:牛粪肥>羊粪肥>猪粪肥>鸡粪肥。

松嫩典型黑土带土壤碳氮磷储量空间分布特征

松嫩典型黑土带分布着高有机质和高肥力的黑土资源,长期超负荷耕作致使土壤有机质含量大幅下降,故开展土壤营养元素储量研究对黑土资源保护和国家粮食安全具有重要意义。以松嫩典型黑土带为研究区,基于野外土壤样本实测数据1057件,利用地统计分析等方法,对0~20 cm耕层内土壤全碳(total corban,TC)、全氮(total nitrogen,TN)和全磷(total phosphorus,TP)空间分布特征及影响因素进行研究。结果表明:松嫩典型黑土带土壤TC、TN、TP储量均高于全国水平,含量分别达19.25、1.88、1.28 g/kg;TC、TN、TP高密度热值区和高聚集区主要分布在松嫩典型黑土带北部,TC、TN、TP自北向南呈现降低趋势;C∶N、C∶P和N∶P在该区北部空间聚集性较高;土壤粉粒含量在30%以上,TC、TN和TP含量较高,分别介于6.86~74.74 g/kg、0.94~5.93 g/kg、0.66~3.76 g/kg;TC、TN和TP储量受土壤pH、年均温度、年均降水量和地形等因素影响较大。研究为黑土资源保护和农业可持续发展提供科学依据。

松嫩盆地深部干热岩体岩石热物性特征研究

对采自GR1井钻孔的10块岩心样品开展了热导率、生热率、密度及孔隙度等物性参数测试,揭示其空间展布特征、相互关系及主控因素,建立了松辽盆地中部研究区新生界地层平均热导率和生热率,估算盆地沉积物的放射性生热贡献约占地表热流的33%。研究表明,埋深3900~4000 m段砂岩、砾岩具备良好的传热效果,可作为水平段换热目的层,这些实测的岩石热物性参数为松嫩沉积盆地的盆地模拟与地热相关研究提供了坚实的基础数据。

黑龙江省松嫩平原地区HLJCORS实时定位性能分析

利用黑龙江省卫星定位连续运行综合服务系统(HLJCORS)在黑龙江省的松嫩平原地区开展多方面性能测试,评估系统的实时定位精度、可用性和时效性,结果表明,HLJCORS的内外符合精度均满足规范要求,能够全天候地为松嫩平原地区提供稳定可靠的厘米级实时定位服务。

松嫩草甸草原植物群落物种组成和多样性对刈割和长期放牧的响应

为明晰不同利用方式对松嫩草甸草原不同植物群落物种组成和多样性的影响,本研究通过对松嫩平原西部地带性植被草甸草原在刈割和长期放牧利用下两种典型群落-羊草(Leymus chinensis)群落和野古草(Arundinella hirta)群落的调查与分析,探究了两种利用方式对群落植物物种组成、重要值、生活型、数量特征及多样性等指标的影响。结果表明:刈割和长期放牧下羊草群落物种数为18种和21种,禾本科植物占比最高,分别为33.3%和45.45%;野古草群落物种数分别为39种和32种,禾本科植物占比为23.1%和21.9%。长期放牧增加羊草群落地面芽植物和野古草群落一年生植物占比,降低野古草群落地面芽植物占比。两种利用方式下两个群落饲用价值类型均以优良牧草的种类最多,占比分别为58.76%(刈割羊草群落)、53.33%(长期放牧羊草群落)、46.56%(刈割野古草群落)和46.63%(长期放牧野古草群落)。长期放牧显著降低了两个植物群落的盖度、高度和生物量(P <0.05)。与刈割相比,长期放牧下植物群落的Shannon-Wiener多样性指数和Simpson多样性指数均呈增加趋势。长期放牧下羊草群落和野古草群落S?rensen相似性指数更高,两个群落植物物种相似度更高;而Cody指数在刈割利用下更高,两个群落物种组成在刈割利用下的变化幅度更大。刈割和放牧对松嫩草甸草原不同植物群落的组成和多样性能够产生不同程度的影响,合理适度的利用方式和保护措施将更有利于对草原资源的可持续利用。

Estimates of loss in ecosystem service values of Songnen plain from 1980 to 2000

Ecosystem services are premises for human beings to exist and develop in the world, and it is of importance to study effects of land use change on ecosystem functions. Songnen plain, located in Northeast China, is one of the national key bases for agricultural production. Because there were remarkable variations in land use in recent years, it can supply specific foundation for protection and restoration of regional eco-environment to explore changes in its values of ecosystem services. This study aims to qualify long-term changes in land use of Songnen plain from 1980 to 2000, and to explore the impact of land use change on ecosystem services. With 2-period land use data using RS and GIS, this paper analyzed changes in land use and in ecosystem service values using the ecosystem service value coefficients (VC) put forward by Costanza et al. Results showed that from 1980 to 2000, area of rangeland, water area and wetlands and area of cropland decreased, but urban area and unused land increased. Due to cropland's comparatively low VC and comparatively high VC of wetlands and water area, increment in cultivated land could not offset the total decrement in regional ecosystem service values because of the decrease in area of wetlands and water area. Meanwhile, city sprawl has also led to loss of ecological values. Total ecosystem service values of the study area reduced dramatically, from 34,926.10×106$ to 31,744.54×106$ in the period 1980-2000. This represents a 9.11% net decline in annual value of ecosystem services in the study area.

2.7 Ga Monzogranite on the Songnen Massif and Its Geological Implications

Objective The formation and evolution of Songnen massif has always been a hot topic,and the presence of Precambrian basement on the Songnen massif is still controversial:(1)Lacking of Pre-Paleozoic dating results,the Precambrian basement on Songnen massif does not extend largely according to the isotopic dating results of core from basement,(2)the existence of gneiss from deep drill holes

Age and geochemistry of Early Ordovician A-type granites in the Northeastern Songnen Block,NE China

Early Ordovician A-type granites in the northeastern(NE) Songnen Block NE China were studied to better understand the geodynamic settings in this region.This research presents new zircon U–Pb ages and wholerock geochemical data for the Early Ordovician granites in the NE Songnen Block. Zircon U–Pb dating indicates that the granite in the Cuibei, Hongxing, and Meixi areas in the NE Songnen Block formed in the Early Ordovician with ages of 471–479 Ma. The granites show geochemical characteristics of high SiO2 and K2 O compositions and low FeOT, MgO, CaO, and P2 O5 compositions. They belong to a high K calc-alkaline series and display a weak peraluminous featurPe with A/CNK values of 0.98–1.14. The rocks have aREE composition of 249.98–423.94 ppm,and are enriched in LREE with(La/Yb)Nvalues of2.87–9.87, and display obvious Eu anomalies(d Eu =0.01–0.29). Trace elements of the studied granites are characterized by enrichment in Rb, Th, U, Pb, Hf, and Sm,and depletion of Ba, Nb, Ta, and Sr. They display geochemical features of high Zr +Y + Nb+Ce values(324–795 ppm) and Ga/Al ratios consistent with A-type granites. Based on particular geochemical features, such as high Rb/Nb(7.98–24.19) and Y/Nb(1.07–3.43), the studied A-type granites can be further classified as an A2-type subgroup. This research indicates that the Early Ordovician A-type granites were formed by the partial melting of ancient crust in an extensional setting. Lower Sr/Y and(Ho/Yb)Nratios indicate that plagioclase and amphibole are residual in the source, and garnet is absent, implying that the magma was generated at low levels of pressure. By contrast, the contemporaneous granites in the SE Xing'an Block suggest a subduction-related tectonic setting, and its adakitic property indicates a thickened continental crust.We suggest that the Paleo-Asian Ocean plate between the Xing'an and Songnen blocks subducted northward during the Early Ordovician. Meanwhile, the NE Songnen Block was exposed to a passive continental margin tectonic setting.

Effect of Autumn Cutting Date on Regrowth, Turning Green, Yield and Quality of <i>Leymus chinensis</i>Grassland in Songnen Plain, Northeast China

A field study was carried out to quantify the effects of different cutting time on Leymus chinensis population and community characteristic in Songnen grassland of northeast China from August, 2006 to August, 2007. The treatment interval was ten days with the remaining stubble height of 5 cm from 15th August to 4th October in 2006. Results showed that the L. chinensis made up about 90% of the dry matter of aboveground biomass, and there were about ten species in the L. chinensis community in the 1 m × 1 m plot. The L. chinensis and Kalimeris integrifolia regrew rapidly after autumn cutting in 2016. In the second year, the coefficients of the community similarity were high between the different cutting time treatments. The density, height, aboveground biomass, stem/leaf ratio, and crude protein of L. chinensis were not significant at the turning green stage and harvesting stage, the companion species of L. chinensis community contained higher crude protein, but the crude protein of the plant community were not significant. Thus, considering the weather factor for haymaking, the harvest dates should be concentrated from the middle ten days of August to the first ten days in September.