The ecological functions of Arbuscular mycorrhizal fungi （AMF） were explored by investigating its effects on maize growth， mineral nutrition， low-molecular-weight organic acid secretion， and Cd uptake via a root-bag experiment in soil polluted with Cd in the Huize lead-zinc mining area of Yunnan Province. The results showed that AMF promoted maize growth and significantly increased photosynthetic rate， plant height， and biomass. The absorption of N， P， and K increased by 14.2–19.1-fold， and tartaric acid， malic acid， oxalic acid， and succinic acid secretion by roots increased by 1.1–3.8-fold. In addition， AMF resulted in a significant increase of 22.6% in iron- and manganese-oxidized Cd content and a significant decrease of 12.9% in organic-bound Cd content in the maize rhizosphere， but no significant change in exchangeable and available Cd content was observed. AMF significantly reduced maize shoot and root Cd content by 32.6% and 77.0%， respectively， but significantly increased Cd uptake in maize shoot and root by 12.5-fold and 25.7%， respectively. Correlation analysis showed that shoot Cd uptake presented significant positive correlations with oxalic acid， tartaric acid， malic acid， and succinic acid secretion， and iron- and manganese-oxidized Cd content. Thus， these results showed that AMF can promote the absorption of nutrients in maize， regulate the secretion of low-molecular-weight organic acid and Cd form in the rhizosphere， and reduce maize Cd content， thereby promoting plant growth.
This study investigated the effects of cover crops on aggregate stability and organic carbon fractions of the Shajiang black soil in the Huabei Plain. Four cover cropping treatments （fallow， alfalfa， oilseed rape， and radish with hairy vetch mixture） with or without compaction operations were used in this study. Soil samples were collected from layers at depths of 0-10 cm and 10-20 cm. Soil aggregate size distribution， soil organic carbon （SOC）， and its fractions （particulate organic carbon， POC and soil mineral-associated organic carbon， and MOC） were measured. The results showed that cover crops significantly increased SOC content in the 0-10 cm soil layer when compared with the fallow treatment （P＜0.05）， particularly in the case of alfalfa treatment （14.3%）. Only the alfalfa treatment increased SOC in the 10-20 cm soil layer （9.17%-10.8%， P＜0.05）. The alfalfa treatment significantly enhanced mean weight diameter （MWD） in both soil layers compared with the fallow treatment. The three cover crop treatments significantly increased the amount of ＞2000 μm aggregate in the 0-10 cm soil layer as compared to the fallow treatment， but no significant increase was observed in the 10-20 cm soil layer （with an exception of the alfalfa treatment）. The alfalfa treatment significantly increased SOC of aggregates ＞2000 μm， 250-2000 μm， and 53-250 μm in both the soil layers. Cover crops significantly augmented the POC compared with the fallow treatment; the largest increase was found with the alfalfa treatment regardless of the soil layers （25.2%-34.5%）. Cover crops had no effects on MOC. Compaction had no effects on the SOC， MWD， POC， and MOC. The study showed that cover crops， particularly alfalfa， significantly boosted POC content and hence promoted SOC accumulation， thus enhancing the Shajiang black soil quality.
Denitrification is one of the most important reactive nitrogen removal pathways in the soil nitrogen cycle. In this process， nitrate is reduced to gaseous nitrogen nitrous oxide (N 2 O) or nitrogen (N 2 )， which leaves the soil and enters the atmosphere. The stoichiometric ratio of its gaseous products N 2 O/N 2 is a hot topic in soil denitrification research. Reasonable regulation of this ratio is an important way to reduce greenhouse gas emissions from agricultural sources. In the soil environment， the ratio of denitrification products is affected by many factors. In our view， nitrate content， oxygen， and copper availability are the key factors mediating the change of the product ratio， while electron donors， pH， and moisture are general factors. These factors can directly affect the denitrification process by affecting denitrifying enzyme activity， denitrifying microorganism abundance， and community structure. They can also indirectly affect the ratio by changing the soil microenvironment of denitrification. This paper reviews the progress made toward controlling the factors affecting the soil denitrification gaseous product ratio N 2 O/N 2 in recent years and discusses the response mechanism of the denitrification product ratio to different influencing factors to provide some inspiration for future related research.
为从生理学角度研究硫元素施加对小花南芥(Arabis alpina L.var.parviflora Franch)硫同化关键酶活性及富集铅的影响,设置铅(Pb2+1000 mg·kg-1)胁迫下施用不同浓度(0、25、50、100、200、400 mg·kg-1)硫处理的盆栽试验,测定植株体内铅、硫和硫合成物质含量以及硫同化关键酶活性,分析施硫条件下小花南芥生长、硫同化关键酶活性、铅含量的变化规律以及硫同化关键酶对小花南芥累积铅的影响.结果表明:与对照相比,硫处理浓度为400 mg·kg-1 时小花南芥地上部和地下部生物量分别显著增加125.80%和71.50%,在硫处理浓度为50 mg·kg-1时,地上部生物量差异不显著,但总根投影面积、总根表面积和总根体积显著增加了1.2、1.4倍和4.5倍,小花南芥地上部硫酸化酶(ATPS)、γ谷氨酰半胱氨酸合成酶(γ-ECS)、半胱氨酸合成酶(OAS-TL)、亚硫酸盐还原酶(SUR)活性分别增加了21.66%、29.80%、15.08%、48.95%,地下部和地上部的半胱氨酸含量分别增加了18.10%、11.93%;硫处理浓度为100 mg·kg-1时,小花南芥地上部乙酰丝氨酸水解酶(OASS)、螯合肽合成酶(PCSase)、腺苷酰硫酸还原酶(APSR)活性分别显著增加了24.27%、19.29%、36.71%,地上部的半胱氨酸含量增加了7.96%;在硫处理浓度为50、100 mg·kg-1时铅的富集系数大于1.小花南芥地上部铅含量与地上部OAS-TL、γ-ECS和SUR存在显著正相关性;小花南芥地下部铅含量与地下部γ-ECS和APSR存在显著正相关性,与地下部OAS-TL、半胱氨酸(Cys)和PCSase存在显著负相关性.研究表明,适当施硫(50～100 mg·kg-1)可以促进小花南芥的生长,改变根系形态,提高硫同化关键酶活性和含硫化合物的含量,增强小花南芥对铅的富集和耐受能力.
Our research is aimed at exploring quality differences in different water sources， and the influence on quality of precipitation， shallow groundwater depth， and other factors in an agricultural ecosystem. Samples of flowing surface water and shallow groundwater were collected from 4 locations near the National Agro-ecological System Observation and Research Station of Shangqiu in Henan province to monitor water quality from 2011 to 2020. Quality of these two water sources was studied as a dynamic process to identify influencing factors using descriptive statistics and a time series analysis method. Ca 2+ ， Mg 2+ ， Na + ， HCO 3 - ， SO 4 2- and Cl - content and electrical conductivity were usually higher in poorly renewed shallow groundwater than in flowing surface water. Rises in the underground water table caused by increased precipitation could promote salt ion migration from top soil to groundwater， thereby amplifying discrepancies between these two kinds of water. spanning 10 years of monitoring， peak values were observed for all ions， during which Na + ， Ca 2+ and SO 4 2- in flowing surface water and K + in shallow groundwater reached their maxima in March 2012 and September 2011 respectively. The hydrochemical types of these two waters were consistently similar over time. Although seasonal variation exerted less influence on periodical ion content changes， the long-term dynamic interaction between precipitation and the groundwater table notably regulated the hydrochemical type and ion flux in the waters. In the scenario in which increased precipitation raised the water table， shallow groundwater SO 4 2- ， and Cl - levels could easily exceed the threshold for agricultural production suggested by groundwater quality criterion （GB/T 14848—2017）， rendering it unsuitable for irrigation. This study confirmed that long-term quality in flowing surface water and shallow groundwater was dynamically influenced by long-term changes in precipitation and groundwater depth in a typical agricultural ecosystem in eastern Henan， which can provide a reference for water quality risk management in farmland environments and water source selection in local agriculture production.
We studied the safety of silicon and selenium fertilizer leaf regulation on rice polluted with cadmium and plumbum. Through the field experiment， set silicon and selenium fertilizer leaf surface regulation treatment， the single dosage is 1.5 L·hm -2 ， after adding water to dilute 400 times， silicon and selenium fertilizer leaf surface regulation is carried out at the tillering stage， heading stage and filling stage of rice growth. The effects of cadmium and plumbum pollution on rice yield， concentration in brown rice， absorption and transport in different parts of rice， and nitrogen， phosphorus， and potassium concentration in brown rice were studied. The results showed that the yield with spraying silicon fertilizer twice at the heading and filling stage was 4.49% higher than that with the blank and significantly higher than that with single spraying. Foliar selenium fertilizer treatment could increase yield by 3.21%–5.08%， with significant difference compared with the blank （P＜0.05）. The effect of spraying silicon （33.64%） or selenium （34.67%） twice at heading stage and filling stage for reducing cadmium and plumbum was significantly higher than that of single spraying only at heading stage or filling stage （P＜0.05）. According to the national standard for food safety （GB 2762—2022）， spraying silicon fertilizer or selenium fertilizer twice or more can make the cadmium concentration in brown rice reach the standard (＜0.2 mg·kg -1 )， and spraying once can make the plumbum concentration in brown rice reach the standard (＜0.2 mg·kg -1 ). The concentration of cadmium and plumbum in brown rice decreased with the increase in spraying times. Leaf control of silicon and selenium fertilizer could reduce the enrichment capacity of cadmium and plumbum in rice plants， and the reduction of cadmium and plumbum enrichment coefficient was between 10.81%-26.96% and 3.04%-69.57%， respectively. The leaf surface regulation of silicon and selenium fertilizer can reduce the cadmium and plumbum concentration in brown rice by reducing the ability of heavy metal cadmium and plumbum in rice to transport to brown rice. （4） The concentration of silicon and selenium in brown rice was 2.227–2.550 mg·kg -1 and 0.145–0.176 mg·kg -1 ， respectively， which was significantly increased by leaf surface regulation of silicon and selenium fertilizer （P＜0.05）. Spraying leaf silicon or selenium fertilizer twice or more during rice growth period increased the concentration of nitrogen， phosphorus， and potassium in brown rice more significantly （P＜0.05）. According to comprehensive analysis， spraying silicon or selenium twice on the leaves of rice at heading stage and filling stage can reduce the concentration of cadmium and plumbum in brown rice to below the limit value specified in national standard for food safety， and improve the concentration of nitrogen， phosphorus， and potassium in brown rice， which is operable and has high economic benefits.
为探讨柑橘园生草覆盖及配合化肥减量对地表径流氮磷流失的影响,本研究于2014-2021年在湖北清江流域开展了连续7年的野外径流小区监测试验.在自然降雨条件下设置清耕对照(CK)、生草覆盖(KF)和生草覆盖配合化肥减量(BMP)3个处理,探讨生草覆盖及生草覆盖配合化肥减量对柑橘园周年及主要时期的地表径流量、氮磷流失量、氮磷浓度的影响.结果表明:与CK相比,KF和BMP处理均能显著降低柑橘园中的总氮(TN)和总磷(TP)流失量,且BMP处理效果更好,其中,KF处理TN和TP流失量分别降低48.2%和50.0%,BMP处理TN和TP流失量分别降低54.2%和57.1%,BMP对氮磷流失量的削减效果主要是生草覆盖所起的作用.与CK相比,KF和BMP处理径流量分别减少了44.3%和50.1%,产流系数分别降低了3.3个百分点和3.8个百分点;KF处理地表径流中TN和TP浓度分别降低了11.0%和14.1%,BMP处理地表径流TN和TP浓度分别降低了11.9%和18.8%.柑橘园氮磷流失风险期为4-8月,在6-7月暴雨施肥耦合期,BMP处理减排效果最好,TN和TP流失量分别降低了54.6%和64.4%,但仅比KF处理分别高2.7个百分点和6.9个百分点.研究表明,生草覆盖和生草覆盖配合化肥减量均能显著削减柑橘园地表径流氮磷流失量和地表径流量,且主要是通过生草覆盖降低地表径流量实现削减氮磷流失量,在氮磷流失风险期和暴雨施肥耦合期采取生草覆盖配合化肥减量措施能有效减少柑橘园地表径流氮磷流失.
Bioremediation of Cd-polluted soil using metal-resistant bacteria has received increasing attention. In the present study， pot experiments were conducted to investigate the changes in soil Cd speciations， rice grain Cd accumulation， and soil microbial community structure after different Delftia sp. B9 biomass inoculations in the soil. Additionally， the optimum additive amounts of B9 were applied in the field experiments to verify the reductions of Cd in rice grain. The results showed that all different treatments with B9 biomass inoculations significantly increased soil pH and decreased the content of bioavailable Cd （extracted by DTPA） by 4.72%-15.65%. In comparison with CK， treatments with B9 addition decreased the Cd concentration in grains by 22.87%-59.90%; all grain Cd levels in the pot trials were within the acceptable range for food security in China (0.2 mg·kg -1 ). T2 (B9 application: 1.28 g·pot -1 ) was the most effective remediation treatment that enhanced soil Cd fractionations into more stable forms and significantly reduced Cd accumulation in rice grains. The treatment T2 significantly increased the operational taxonomic units （OTUs） and microbial community richness and diversity indexes （ACE， Chao1， and Shannon）. The relative abundance of Proteobacteria （B9 is a member of this phylum） increased significantly. The application rate of B9 was 12.50 g·m -2 ， which significantly reduced the Cd accumulation by 28.38%-91.18% for rice grains in field conditions. Studies have shown that the application of B9 reduces the potential environmental risks posed by Cd in soils and improves food safety.
To investigate Zn translocation distribution of hyperaccumulator Arabis alpina L. var. parviflora Franch， a pot experiment was conducted to study the effects of different concentrations of Zn (0， 100， and 300 mg·kg -1 ) on the pectin content， PME activity， transporters CAX， HMA， and ABC activities， and organic acid （oxalic and citric acid） contents of A. alpina. The results showed that the Zn contents in shoots tended to increase with the increase of Zn treatment concentrations. The Zn contents in roots reached the maximum at 100 mg·kg -1 Zn treatment， and the distribution of Zn content in plants was greater in roots than in shoots. With 300 mg·kg -1 Zn treatment， the Zn content in the symplast sap was 85.80% higher than that in the apoplast sap， and the Zn content in the phloem sap was 4.56 times higher than that in the xylem sap. The pectin content in roots decreased with the increase of Zn treatment concentrations， and PME activities increased in roots and shoots. The highest activities of CAX and HMA in the leaves were achieved with 300 mg·kg -1 Zn treatment， which increased by 52.54% and 38.73%， respectively， compared to the control. Oxalic acid content was the lowest in roots and highest in leaves with 100 mg·kg -1 Zn treatment. Under 300 mg·kg -1 Zn treatment， citric acid content was the highest in xylem sap and leaves， increasing by 161.10% and 107.88% compared to the control， respectively. The Zn contents in the roots of A. alpina showed a highly significant positive correlation with PME activity， and a significant negative correlation with HMA and ABC activities and oxalic acid content. The content of Zn in shoots of A. alpina showed a highly significant positive correlation with CAX and HMA activities and xylem citric acid content. In general， the results indicated that Zn in A. alpina transportation is relative to reducing pectin content and enhancing membrane transporter protein activities and citric acid contents.
为探讨长期不同施肥模式下杂草群落变化及其与土壤养分相关性,依托一项连续24年长期施肥试验,采用田间调查法,对不平衡施肥[氮磷肥(NP)、磷钾肥(PK)、氮钾肥(NK)]、常量化肥(NPK)、单施有机肥(M)、1/2有机肥替代化肥(1/2MNP)、不施肥(CK)模式下黄壤单季稻冬闲田春季杂草群落变化及其与土壤养分相关性进行研究.结果表明,长期不同施肥模式下春季杂草密度、生物量、群落多样性等均发生变化.M处理下土壤养分均较高,杂草群落总密度1208.44 株·m-2、总生物量1071.24 g·m-2,均为最高,与CK处理相比,春季杂草总密度增加37.74%、总生物量增加179.58%,说明单施有机肥可提升土壤养分,促进春季杂草生长.不同处理对杂草群落影响存在差异:M处理下棒头草(Polypogon fugax)等未发生;长期施用无机化肥处理早熟禾(Poa annua)发生密度(0～4.89株·m-2)较低;缺磷处理下日本看麦娘(Alopecurus japonicus)发生密度(36.00株·m-2)最低.同时,缺氮导致杂草群落多样性指数增加、优势度指数降低,群落结构相对复杂;缺磷则反之.研究表明,全氮、碱解氮和全磷是影响杂草密度的关键因子,生产上可通过合理施肥控制田间杂草发生,稳定土壤肥力及物种多样性,促进农业生态系统发挥出最大生态效应.
为厘清中国耕地利用转型的研究热点和阶段性研究前沿,以CNKI文献为基础数据来源,采用文献计量学分析方法,结合VOSviewer和CiteSpace两款可视化软件,定量分析2000-2022年发表的相关文献.结果表明:中国耕地利用转型研究成果发文量随时间推移出现2个不同增速的发展阶段;中国耕地利用转型研究除对相关概念的深入阐述外,形态特征、驱动机制、转型途径等主题是该领域的研究热点;中国耕地利用转型经历了3个阶段,即相关基本概念及内涵的引入和界定、粮食安全背景下的耕地利用转型研究、生态文明建设背景下的耕地利用转型研究.研究表明:转型形态特征方面,耕地利用隐性转型研究相对匮乏,对耕地利用显性转型或隐性转型的单一视角研究较多;驱动机制方面,自然、经济、社会是分析耕地转型驱动机制的3个主要层面;转型途径方面,耕地功能形态的诊断是当前耕地利用转型的研究热点,构建耕地功能度量指标体系是当前耕地利用转型途径的重点.
Soil texture affects soil water content and fertilizer and air permeability， and drives multiple physical and chemical processes occurring in the soil. Developing efficient and fast remote sensing technologies to predict the spatial distribution of soil texture has important theoretical and practical applications in soil quality evaluation and agricultural production planning. This paper discusses the application of remote sensing data， methods and models to predict soil texture， and the use of auxiliary data such as radar， terrain， and vegetation index data for soil texture prediction by remote sensing. The paper also proposes three methods for predicting the spatial distribution of soil texture based on remote sensing characteristics; namely， spectral response， characteristic wavelength selection， and remote sensing interpretation. It also focuses on the application effects of statistics， geostatistics， and machine learning models combined with remote sensing on spatial prediction of soil texture. The advantages， disadvantages， and application of several typical methods are compared， and the application conditions and accuracy verification methods of remote sensing prediction of soil texture are analyzed. Future research needs to focus on in-depth extraction of various remote sensing spectral features， acquisition of multiple types of environmental variables by remote sensing technologies， and development of a multi-algorithm hybrid model combining soil physical properties and data-driven machine learning features， so as to provide a basis and technical support for the spatial prediction of soil texture at different regional scales.
生态保护重要性评价是开展生态保护工作的科学基础.本研究基于自然资源数据库对陕西省生态保护重要性进行评价,在此基础上使用生态网络分析的方法对生态保护重要性评价结果进行优化,进而构建陕西省生态保护空间格局.结果表明:陕西省生态系统调节功能极重要区面积为67562.30 km2,占全省总面积的32.8%,主要分布在秦巴山地、关山和子午岭地区;生态极敏感区面积为13260.88 km2,占全省总面积的6.4%,主要位于黄土高原地区.研究区内包括30处生态源地和106处生态节点,呈现出南多北少、西多东少的分布特点,103条生态廊道则以南北纵向分布为主.利用生态网络对生态保护重要性初始评价结果进行优化,识别并增加3.3%生态保护极重要区域.全省生态保护极重要区面积为84362.30 km2,占全省总面积的40.97%.基于生态保护重要性评价优化结果,可构建点-线-面相结合的网络状生态保护空间格局.本研究通过叠加分析和生态网络相结合的方法构建区域生态保护格局,可以有效提高生态保护与修复区域划定的准确性和科学性.
Under the current situation of comprehensive utilization of straw resources in Wuhu City， the nutrient inputs and their spatial distribution characteristics under straw returning can provide a decision-making basis for coordinating the effective utilization of straw nutrient resources and promoting the reduction and efficiency of agricultural chemical fertilizers. The main straws （maize， rice， wheat， cotton， and rape straw） in Wuhu City in 2019 were chosen as the research objects. According to the crop planting area and nutrient content of straw， the inputs of nitrogen， phosphorus， and potassium nutrients and their weighted coefficients of variation under straw returning per unit area， and the spatial difference characteristics and specific embodiment of nutrient inputs under straw returning in Wuhu city were determined. The results showed that the contents of N， P， and K were 12222， 1746， and 23404 tons， respectively， for the main straws in Wuhu City. Furthermore， the total amount of straw nutrient resources of counties were as follows: Wuwei＞ Nanling＞ Jiujiang＞ Wanzhi＞ Fanchang＞ Yijiang＞ Jinghu. The straw resources per unit planting area of crops in Wuhu City were 5.63 t·hm -2 ， of which corn reached the highest 13.71 t·hm -2 . The inputs of N， P， and K of maize straw returning per unit planting area in Wuhu were 126.16， 20.57， and 161.81 kg·hm -2 ， respectively. The weighted coefficient of variation of the inputs of N， P， and K of straw returning per unit planting area of the main straws in Wuhu City were 0.1375， which indicated moderate variation. The spatial difference was great in Jiujiang and Nanling. The spatial difference of maize straw was the largest， and its weighted coefficient of variation was significantly higher than that of other crop straws in Wuhu City. This finding can help to improve the comprehensive utilization of straw resources and reduce chemical fertilizer imports by organic nutrient replacement in Wuhu City.
过度施肥导致的农业面源污染问题制约着我国农业发展,而完善农田水利设施、加强农业用水管理是促进农业可持续发展的重要举措.国家正在推进的农田水利改革能否在促进农业用水方式改变的同时减少农业面源污染,是值得关注的问题,但目前学界较少从农田水利改革视角为农业面源污染的防治提供新的理论与实践依据.本研究利用云南省陆良县的农户调查数据,通过多元回归模型探索农田水利改革对当地农田氮、磷面源污染排放量的影响,并采用中介效应模型进一步分析其作用机制.结果表明,就灌溉区位条件较差的研究区域而言,在农业活动外部性约束机制尚未建立的背景下,农田水利设施的完善会导致农田氮、磷面源污染排放量增加,这与农户的增产激励行为紧密相关.具体来看,农田水利改革改变了试点村农户的轮作方式、种子用量及灌溉用水量,即由改革前早春农田撂荒或马铃薯少量种植向复耕或扩大马铃薯种植规模转变,农田种子用量及灌溉用水量增加,使得当地农田面源污染风险增大.此外,非农就业比例在农户增产激励行为与农田水利改革之间发挥了一定的调节效应.在灌溉基础相对薄弱的地区进行农田水利改革时,应同步推进农田节水灌溉以及化肥减施、适施等行动,提高农户节水节肥意识,适时开展农业绿色生产技术推广,积极发展农业社会化服务.
为了掌握区域土壤速效钾含量变化特征及其影响因素,本研究在成都平原选择184个20世纪80年代第二次土壤普查时采集的样点数据和176个2016-2017年获得的样点数据,采用一般统计和单因素方差分析法(ANOVA)探究了近40年成都平原农地表层(0～20 cm)土壤速效钾含量变化特征及其与农地利用方式转变和母质类型的关系.结果表明:研究区农地表层土壤速效钾含量从44.44 mg·kg-1增加至57.24 mg·kg-1,增幅为28.80%(P<0.05).与20世纪80年代传统稻-麦/油轮作相比,2016-2017年稻-蔬轮作和稻-麦/油轮作表层土壤速效钾含量分别增加了103.83%(P<0.05)和17.64%,而园林地表层土壤速效钾含量则减少了11.95%.不同母质类型上,灰棕冲积物发育的土壤表层速效钾含量增幅最高,为82.08%(P<0.05),其次是更新统老冲积物(25.48%)和灰色冲积物(9.82%).与传统稻-麦/油轮作相比,稻-蔬轮作下灰棕冲积物发育的土壤速效钾含量增幅(135.97%,P<0.05)远高于更新统老冲积物(116.03%,P<0.05)和灰色冲积物(79.31%,P<0.05),而园林地灰棕冲积物和更新统老冲积物发育土壤的速效钾含量增加,灰色冲积物发育土壤的速效钾含量降低.研究表明,农地利用方式的转变改变了研究区表层土壤速效钾累积特征,但其对累积规律的影响依赖于成土母质类型.
Biomass is the most abundant renewable resource on earth. Promoting conversion and utilization of biomass resources in a scientific and efficient way is the basic starting point for solving resource shortages and implementing carbon peaking and carbon neutrality goals， and the core driving force for developing a circular economy and promoting sustainable production and consumption. Sweden， as one of the first countries in the world to achieve a carbon production peak， started the process of biomass resources conversion and utilization as early as the 1970s. Their policy-and-action path has continued to evolve and improve， gradually forming an energy paradigm reliant on biomass based heating， supplemented by biomass based power generation， with biomass powered transportation as a direction for future development. Due to the current impetus promoting biomass resources conversion and utilization in China， this paper systematically discusses the development context， main policies and actions， and key achievements in biomass resources conversion and utilization in Sweden， and analyzes typical experiences with management and mode of biomass resources conversion and utilization. Combined with the endowment conditions， established demand， and problems facing biomass resources conversion and utilization in China， this paper analyzes potentially viable suggestions from the aspects of top-level design， management systems， conversion and utilization modes， and core technologies， to provide a reference for China’s path to biomass resources conversion and utilization.
为探讨不同类型农业废弃物能源化利用方式对农村能源可持续性的影响,根据1990-2019年黄河流域9省(区)60个地级行政区(市、州、盟)的农作物产量和畜禽数量,采用草谷比法和排泄系数法计算出其农业废弃物资源量.同时,从能源消耗、能源结构、环境排放三方面构建农村能源可持续性指标体系.结果表明:1990-2019年,黄河流域农业废弃物年产生量呈现先增加后减少的"双峰"变化趋势,峰值分别出现在1996年和2006年,分别为6.81亿t和7.06亿t.2019年黄河流域农村能源可持续性平均得分为0.3237,且省域差异显著,呈现上下游高、中游低的空间分布特征.最后,依据不同类型农业废弃物能源化利用方式对农村能源可持续性影响程度、秸秆与畜禽粪便比率以及秸秆资源密度,推荐了适合各地级行政区的农业废弃物能源化利用方式.
生物多样性对农业生态系统粮食安全、生产力和可持续性贡献极大,尤其是在未来全球气候变化加剧的背景下,多物种及其可利用性可为不同条件下农业生产和多种生态过程提供支持.黑土区生态类型多样,是实现我国农业绿色发展的重点区域.然而,由于长期高强度开发利用,黑土区耕地开始退化,湿地、林地等半自然生境面积减少,导致生物多样性下降,严重制约黑土区农业绿色发展.本文在分析黑土区农田生物多样性现状的基础上,对照和借鉴国内外生物多样性保护和农业绿色发展的经验,指出了黑土区农田生物多样性保护存在的主要问题,并进一步提出黑土区集约化农田生物多样性保护对策,以期为黑土地生物多样性复原及农业绿色转型提供理论依据.
为提高砂姜黑土土壤水分的估测精度,本研究以河南省西平县砂姜黑土为研究对象,通过配制不同含水率土壤样本并在室内进行高光谱测量,对土壤样本高光谱数据平滑(SR)、倒对数[LOG(1/R)]、一阶微分(FD)、多元散射校正(MSC)、去包络线(CR)光谱变换后,结合连续投影算法(SPA)识别最佳特征波段,采用偏最小二乘回归(PLSR)、支持向量机回归(SVR)的机器学习方法和堆叠(Stacking)集成学习方法分别构建土壤含水率反演模型.结果表明:经MSC变换后光谱中土壤含水率相关信息增强最多;SPA算法能对砂姜黑土含水率光谱数据进行降维和特征信息提取;经反射光谱MSC变换后由PLSR和SVR集成的Stacking集成模型决定系数最高(R2=0.963)、均方根误差最小(RMSE=1.7).研究表明,Stacking集成学习模型有效提升了模型的精度和泛化能力,是砂姜黑土含水率最佳反演模型.
