泽州县耕地质量建设浅析

泽州县现有耕地41333.3hm2,其中确实能够浇灌的水地面积不足3333.3hm2,纯旱地面积31333.3hm2,占耕地总面积的75%以上。粮田面积38533.3hm2,中低产田就有22000hm2,占粮田总面积的56%以上,大面积中低产田综合生产能力低下,严重制约了我县粮食产量的进一步提高,耕地质量建设成为农业可持续发展的迫切需要。     

汤原县耕地地力调查和质量评价

<正>土乃"八字宪法"之首,为持续开展农田基础设施和耕地内在质量建设,进行了耕地地力调查和质量评价。报告如下:汤原县乡镇耕地总面积为89790.8hm2,旱田面积58980.8hm2,占耕地面积的65.7%;水田面积30810hm2,占34.3%。这次耕地地力调查和质量评价,将汤原县乡镇耕地土壤划分为四个等级:一级地20177.82hm2,占22.48%;二级地34510.11hm2,占38.43%;三级地22558.14hm2,占25.12%;四级地12544.75hm2,占13.97%。其中:高产田为一级地     

基于GIS的县域耕地资源数据库建立及耕地地力评价

用现代耕地资源管理理论和方法,结合GIS技术,在第二次土壤普查资料基础上,通过实地调查对大量数据进行补充,用GIS软件建立了定安县1:50000耕地资源数据库。并在此基础上选取排涝能力、轮作制度、成土母质、土壤侵蚀类型、pH、有机质、全氮、有效磷、速效钾、交换性镁、耕层厚度、障碍层状况12个要素作为评价指标。叠加土壤图、基本农田保护块图或土地利用现状图,得到2411个评价单元。根据模糊数学理论,采用特尔菲法、层次分析法和加法模型计算出耕地地力综合指数,运用等距分级法形成耕地地力等级。在此次以水稻土为主的定安县耕地调查中,查出耕地总面积66729.47hm2,按综合指数分级方案划分的地力等级结果表明,二级地2241.60hm2、三级地27261.27hm2、四级地26065.93hm2、五级地11160.67hm2,分别占定安县耕地总面积的3.36%、40.85%、39.06%、16.73%,没有一级、六级、七级和八级耕地,面积较大的耕地属于三级和四级地,将其归入全国耕地地力体系后,定安耕地整体在全国处于中等级水平。     

闽清县水稻土中低产田现状与改良措施

闽清县耕地调查表明院水稻土土壤是全县主要耕作土壤,面积达17 484.36 hm2,占全县耕地土壤面积的98.34%。其中中低产田面积达14 331.91 hm2,占全县耕地总面积的80.61%。主要低产田类型有干旱型、渍涝型、缺素型和瘠薄型。相应提出加强农田水利设施建设,完善引水渠和田间灌溉渠系,推广测土配方施肥,增施有机肥,逐年加深耕作层等改良中低产田的措施。     

基于GIS的县级设施农业区土壤养分综合评价

采用GIS技术和层次分析法、综合指数法等,对青海省大通县设施农业区土壤养分进行综合评价。结果表明,全县设施农业区1 588.8 hm2耕地可分为3级,其中,1级地IFI(养分综合评价指数)>0.64,面积为288.3 hm2,占总面积的18.1%;2级地IFI为0.52～0.64,面积1 254.2 hm2,占78.9%;3级地IFI<0.52,面积46.3 hm2,占2.9%。并采用归纳法,建立起包含立地条件、理化性状和土壤管理等地力要素的乐都县耕地地力评价指标体系。     

巍山县中低产田地改造初见成效

巍山县国土总面积2200km2,其中,山区面积2052km2,占总面积的93.3%。共有耕地26620hm2,其中常耕地21086.67hm2、水毁及低标准农田5533.33hm2。主要分布在巍山坝子、山箐沟两旁,山区、半山区丘陵、山槽、山洼等地带;旱地12386.67hm2,占58.74%,主要分布在山区。2008年,全县有9213.33hm2中低产田地,占全县总耕地的34.61%。这些中低产田地耕种质量差,农田基础     

基于耕地地力评价成果的条山农场中低产田划分研究

依据条山农场耕地地力评价成果,对条山农场中低产田类型及障碍类型进行了划分,结果表明,中低产田面积占农场耕地总面积的73.2%,其中中产田和低产田分别占农场耕地总面积的49.0%、24.2%。中产田主要分布在农场中部及南部区域,低产田主要分布在北部一条山地带。中低产田障碍类型主要为干旱灌溉型和瘠薄培肥型。     

基于GIS的吉林省县级耕地地力评价与评价指标体系的研究

在耕地地力调查的基础上,采用GIS技术和模糊评价、层次分析和综合指数法等,对吉林省九台市基本农田耕地地力进行评价。结果表明,全市17.60万hm2基本农田耕地可分为6级,其中,1级地IFI(地力综合指数)>0.85,面积为2.07万hm2,占总面积的11.8%;2级地IFI0.8～0.84,面积5.72万hm2,占32.5%;3级地IFI0.75～0.79,面积4.50万hm2,占25.6%;4级地IFI0.70～0.74,面积2.49万hm2,占14.2%;5级地IFI0.65～0.69,面积1.84万hm2,占10.4%;6级地IFI<0.65,面积0.98万hm2,占5.5%。并采用归纳法,建立起九台市耕地地力评价的指标体系。     

黔东南州耕地地力评价

以黔东南州为研究区域,选取大于10℃积温、剖面构型、排水能力、耕层厚度、地形部位、灌溉能力、有机质、全氮、有效磷、速效钾、p H、海拔、成土母质、抗旱能力这14个因素作为评价指标,应用Arc GIS软件,利用各县土壤图、土地利用现状图和行政区划图确定评价单元,从评价单元中获取数据,计算所选因子权重,采用累加法等方法对各黔东南州耕地地力进行评价。结果表明:黔东南州耕地总面积425 806.1 hm2,分为8个地力等级,一级地面积16 605.2 hm2,占3.90%;二级地面积37 157.1 hm2,占8.73%;三级地面积57 481.5hm2,占13.5%;四级地面积81 065.4 hm2,占19.04%;五级地面积94 845.4 hm2,占22.27%;六级地面积941 405 hm2,占14.74%,七级地面积890 504.0 hm2,占13.94%,八级地面积16 524.3 hm2,占3.88%。     

耕地资源管理信息系统的建立及应用 ——以浙江象山县为例

基于GIS技术,将象山县土壤图、土地利用现状图及行政区划图相叠置,确定全县耕地地力评价单元985个。根据象山县实际情况和浙江省确定的15个耕地地力评价因子,采用层次分析法,确定各评价因子权重和隶属度,根据综合地力指数等级将耕地划分为三等六级。评价结果显示：目前县内现有耕地20 742 hm2,其中一等耕地全为二级,面积为458 hm2,占总面积的221%;三级耕地面积为13 3373 hm2,占总面积的6430%,四级耕地面积为6 7126 hm2,占总面积的3236%;五级耕地面积为2341 hm2,占总面积的113%。     

藏东南林芝地区典型农业土地利用方式对土壤微生物群落特征的影响

为研究藏东南林芝地区土壤微生物群落对农业土地利用方式的响应特征及其关键影响因素,可深入认识农业土地利用对该区域生态系统稳定性的影响,并为该地区农业土地资源合理利用提供科学依据。采集藏东南林芝地区2种典型农业土地利用方式(农田及放牧草地)土壤样品,以自然森林土壤样品为对照,利用磷脂脂肪酸法(PLFA)和MiSeq高通量测序分析不同土地利用方式下土壤微生物数量、多样性和群落组成的差异性,并结合土壤理化指标探讨影响土壤微生物群落组成和结构的关键因素。结果表明:与自然森林相比,农田和放牧草地土壤中微生物PLFA总量降低了38.7%~51.8%,其中革兰氏阳性细菌、革兰氏阴性细菌、放线菌和真菌的生物量分别降低了26.1%~47.6%、40.0%~61.1%、44.1%~60.6%和5.2%~31.3%。农田种植显著降低土壤真菌的多样性,其丰富度、香农多样性相比于森林土壤分别降低了53.0%和71.4%,而细菌群落的丰富度、香农多样性则显著降低了15.7%和5.1%。农田种植显著增加土壤细菌中放线菌门(A ctinobacteria)的相对丰度,但是显著降低了浮霉菌门(Planctomycetes)、绿弯菌门(Chloroflexi)和厚壁菌门(Firmicutes)的相对丰度,放牧草地则显著促进拟杆菌门(Bacteroidetes)和蓝藻门(Cyanobacteria)的生长。农业土地利用显著提高土壤真菌群落中担子菌门伞菌纲(A garicomycetes)的优势度,其在农田和放牧草地土壤中的相对丰度分别是自然森林土壤的23倍和19倍,而子囊菌门(A scomycota)和接合菌门(Zygomycota)的相对丰度则分别降低了67.7%~89.6%和58.7%~67.4%。基于距离矩阵的冗余分析表明,土壤细菌和真菌的群落结构在3种土地利用方式下有显著差异。土壤微生物的数量、多样性和群落组成受到土壤pH值、土壤有机碳、土壤C/N等理化性质的显著影响,并且土壤真菌对环境因子改变的响应比细菌敏感。研究表明,典型农业土地利用方式导致藏东南林芝地区土壤微生物群落的数量和多样性相比于自然植被显著降低,并改变细菌和真菌的群落组成和结构,而且真菌对农业土地利用方式的响应比细菌敏感。     

佛山市南海区土壤地力变化趋势分析与对策

根据自1984年以来的土壤监测数据,系统分析了20年来南海土壤地力变化趋势。结果表明,该区土壤存在酸化、有机质含量下降、钾素增加、磷素极大丰富的特点,据此提出推广平衡施肥技术和水旱轮作制度等利用、改良土壤和培肥地力的建议,以期为南海区耕地资源的保护、管理及合理利用提供参考。     

Soil and Water Resources and Land Sustainable Productivity in the Catchment Area with Intensive Management in Hilly Red Soil Regions,China

Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of Hunan Province, the soil and water resources dynamics, fertility evolution characteristics and land productivity changing situation were studied. Fixed observation results from 1993 to 2002 showed that pools covering about 15% of total area could store up 10% of surface runoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio of interception and evapotranspiration in land, storage in pools and drainage was 7:2:1,which ensured the resources and nutrients equilibrium and a benign recycle in the catchment area system, and benefited the aquatic culture and helped to resist seasonal drought. Moreover, the results showed that soil erosion modulus decreased significantly,equal to or lower than soil loss tolerance (≤500 t km-2) in reddish yellow soil regions.Soil organic matter, total and available N content in sloping land, dryland and paddy field increased steadily (＞10%); water storage enhanced by more than 20% in sloping land and dryland in drought season; crop production increased by more than 20%; and production of trees, fruits, tea and fish as well as land productivity increased yearly.     

吉林省旱地土壤有效硫含量及其与土壤有机质和全氮的关系

【目的】 明确吉林省旱地土壤有效硫含量状况及其分布差异,为区域作物合理施硫提供依据。【方法】 采集吉林省不同生态区8种主要土壤类型的232个表层（0—20 cm）土壤样品,利用地统计学方法分析有效硫含量的空间分布特征,比较不同类型土壤有效硫含量差异,并建立土壤有效硫和有机质、全氮的相关关系。【结果】 吉林省旱地土壤有效硫含量为5.8—40.7 mg·kg^-1,均值为18.1 mg·kg^-1,所有样本中缺硫和潜在缺硫的比例分别为27.2%和20.7%。空间分布上,土壤有效硫含量总体呈自东向西逐渐下降趋势,相应的缺硫发生率自东向西逐渐上升。东、中、西三大生态区的土壤有效硫含量均值（缺硫或潜在缺硫发生率）分别为22.3 mg·kg^-1（24.2%）、18.1 mg·kg^-1（40.0%）和14.3 mg·kg^-1（75.6%）。主要分布于东部湿润山区的白浆土、暗棕壤有效硫含量均值分别为22.1和22.0 mg·kg^-1,缺硫或潜在缺硫样本分别占15.2%和28.3%;中部半湿润平原区的黑土、冲积土和草甸土有效硫含量均值分别为18.8、17.1和16.2 mg·kg^-1,缺硫或潜在缺硫样本占比分别为37.9%、63.5%和55.5%;西部半干旱平原区的黑钙土、风沙土和盐碱土有效硫含量均值分别为11.9、14.0和13.9 mg·kg^-1,缺硫或潜在缺硫风险较高,分别占比73.6%、73.3%和75.5%。回归分析结果显示,吉林省旱地土壤有效硫和土壤有机质、土壤全氮均呈显著的对数相关关系,随着土壤有机质和土壤全氮含量增加,土壤有效硫含量也随之提升。【结论】 吉林省旱地土壤有效硫含量在不同区域和土壤类型之间存在显著差异,硫素缺乏现象也较为普遍,47.9%的土壤样本存在缺硫或潜在缺硫问题,特别是中西部地区的风沙土、盐碱土和黑钙土缺硫风险较高,在土壤培肥和作物管理中应注重硫素的补充。     

Soil Quality Assessment of Acid Sulfate Paddy Soils with Different Productivities in Guangdong Province,China

Land conversion is considered an effective measure to ensure national food security in China, but little information is available on the quality of low productivity soils, in particular those in acid sulfate soil regions. In our study, acid sulfate paddy soils were divided into soils with high, medium and low levels based on local rice productivity, and 60 soil samples were collected for analysis. Twenty soil variables including physical, chemical and biochemical properties were determined. Those variables that were significantly different between the high, medium and low productivity soils were selected for principal component analysis, and microbial biomass carbon (MBC), total nitrogen (TN), available silicon (ASi), pH and available zinc (AZn) were retained in the minimum data set (MDS). After scoring the MDS variables, they were integrated to calculate a soil quality index (SQI), and the high, medium and low productivity paddy soils received mean SQI scores of 0.95, 0.83 and 0.60, respectively. Low productivity paddy soils showed worse soil quality, and a large discrepancy was observed between the low and high productivity paddy soils. Lower MBC, TN, ASi, pH and available K (AK) were considered as the primary limiting factors. Additionally, all the soil samples collected were rich in available P and AZn, but deficient in AK and ASi. The results suggest that soil AK and ASi deficiencies were the main limiting factors for all the studied acid sulfate paddy soil regions. The application of K and Si on a national basis and other sustainable management approaches are suggested to improve rice productivity, especially for low productivity paddy soils. Our results indicated that there is a large potential for increasing productivity and producing more cereals in acid sulfate paddy soil regions.     

不同利用方式下土壤矿物结合态有机碳特征与容量分析

【目的】土壤矿物结合态有机碳是土壤有机碳固持的重要机制之一。探讨不同利用方式下土壤有机碳及矿物结合态有机碳（＜53 µm）的含量、分配比例及其差异性特征,对于深刻认识土壤碳的固持状态、固碳潜力及其可持续管理均具有重要意义。【方法】通过从中国知网、万方、Science Direct和Springer link等4个文献数据库,设定检索条件“2000-2014年”、“中国土壤有机碳”和“＜53 µm团聚体分组”3个关键词,筛选出已发表的111篇目标文献,收集901组土壤有机碳和矿物结合态有机碳含量与比例的相关数据集。其中,土地利用方式分为4类：农田（n=580）、草地（n=98）、林地（n=193）和其他（果园、茶园等,n=31）。农田包括黑土、水稻土、棕壤、潮土、红壤和灰漠土等六大土壤类型。不同利用方式及土壤类型中有机碳含量与分配比例的差异性均采用Kruskal-Wallis H单向显著性检验。【结果】不同利用方式下土壤总有机碳和矿物结合态有机碳含量的中值均存在显著差异（P＜0.05）。其中,林地土壤总有机碳含量的中值为18.2 g·kg^-1,显著高于草地（12.0 g·kg^-1）和农田（10.3 g·kg^-1）;且林地矿物结合态有机碳含量（12.0 g·kg^-1 soil）也显著高于农田和草地（8.0-7.6 g·kg^-1 soil）。3种利用方式下土壤矿物结合态有机碳与总有机碳之间均呈现极显著的正相关关系（P＜0.001）,农田土壤矿物结合态有机碳所占比例的中值为74.8%,显著高于林地（70.3%）和草地（67.8%）。农田中不同土壤类型的矿物结合态有机碳占总有机碳的比例也存在显著差异。其中,黑土中矿物结合态有机碳的比例最高,中值为87.4%,其次是水稻土（76.7%）和红壤（74.0%）,而灰漠土最低（62.5%）。相关分析表明,土壤有机碳水平相对较高的黑土、水稻土和棕壤,矿物结合态有机碳分配比例随着土壤有机碳含量的增加而显著降低（P＜0.05）。农田、草地和林地中土壤矿物结合态有机碳含量与土壤细颗粒（＜53 µm）含量均呈极显著的正相关关系,与Six等（2002）的估算结果相比,其饱和程度分别为68.4%、58.7%和91.5%。【结论】农田和草地中,土壤矿物结合态有机碳还未达到饱和,仍有一定的提升空间,土壤细颗粒（＜53 µm）仍具有一定的固碳潜力。     

Quality Change of Cinnamon Soil Cultivated Land and Its Effect on Soil Productivity

【Objective】The quality of cultivated land is a key factor affecting soil productivity, which serves also as scientific basis for rational fertilization. Cinnamon soil is the main soil type at the production area of wheat and corn in China. This study examined the current status of cultivated land quality and the evolution characteristics of cinnamon soil during the past 31 years (1988-2018). Though considering the evolution of fertilizer application rate, their influence on productivity was studied, and the guidance for reducing fertilizer input and increasing efficiency in cinnamon soil area was proposed.【Method】Using the data of 103 long-term (31 years) location test points in China, the evolution of cinnamon soil cultivated land quality was analyzed by combining physical and chemical indexes. The factors influencing the yield were compared through the redundancy analysis (RDA). Based on these results, reasonable suggestions were put forward to reduce fertilizer input and increase efficiency in cinnamon soil area.【Result】(1) The present situation and evolution of soil physical and chemical properties in cinnamon soil area were shown in the study. Specifically, the average values of organic matter content, available phosphorus and available potassium in 2018 were 17.9 g·kg ^-1, 29.2 mg·kg ^-1-and 164 mg·kg ^-1, respectively, which represented an increase of 21.2%, 200.9% and 52.0% during 31years, respectively. The average values of total nitrogen and slow available potassium in 2018 were 1.1 g·kg ^-1 and 945 mg·kg ^-1, respectively, which remained relatively stable during the monitoring period. The contents of soil secondary elements and micronutrient elements and heavy metals were in an acceptable range. The pH was reduced by 0.3 unit. Topsoil thickness was 21.9 cm and bulk density was 1.33 g·cm ^-3, which belonged to the middle level. (2) The fertilizer application rate in cinnamon soil area was 730.2 kg·hm ^-2 in 2018. The proportion of N (N):P (P₂O₅):K (K₂O) was about 2:1:1, and the proportion of chemical fertilizer to organic fertilizer was about 3.45:1. The nitrogen fertilizer application rate was 378.9 kg·hm ^-2, which was stable during the past 31 years. The application rate of phosphate and potassium fertilizer decreased by 24.1% and 50.8%, respectively. (3) The wheat yield showed an upward trend during 31 years, and the maximum reached 6 651 kg·hm ^-2 at the end of monitoring, which was 27.6% higher than the value at the initial stage. The corn yield was stable, reaching 8 851 kg·hm ^-2 at the end of monitoring. The contribution rate of soil fertility in wheat season and corn season was 49.0% and 59.6%, respectively. The yield was influenced by soil physical factors, including the thickness of plough layer (which could explain the wheat production for 2.7%, denoted as explanation rate), bulk density (explanation rates of wheat and corn productions for 1.2% and 1.5%, respectively) and chemical index, such as organic matter explanation rates of wheat and corn productions for 2% and 1.7%, respectively, and available phosphorus (explanation rate of corn for 3.6%). The explanation rates of potassium fertilizer were the highest for wheat and corn productions, which reached 5.6% and 6%, respectively. The explanation rates of phosphorus fertilizer for wheat yield (1.3%) and of nitrogen fertilizer for corn yield (1.3%) were also relatively high.【Conclusion】The cultivated land quality in cinnamon soil area has been improved in 31 years, but the overall fertility was low and the physical properties were in middle level. Considering the impact of land quality on productivity, different fertilization schemes needed to be formulated for wheat and corn. Both of which needed to increase the input of potassium fertilizers, and focused on ensuring the supply of phosphorus fertilizers for wheat and nitrogen fertilizers for corn. Physical indicators needed to be highly concerned. The topsoil thickness and bulk density were at a medium level, but there was no need to continue to optimize, and maintaining the status quo was more conductive to obtaining high yield.     

Soil Properties and Characteristics of Soil Aggregate in Marginal Farmlands of Oasis in the Middle of Hexi Corridor Region, Northwest China

The composition and stability of soil aggregate are closely related to soil quality, soil erosion, and agricultural sustainability. In this study, 49 soil samples at the 0-10 cm surface layer were collected from four soil types (i.e., Ari-Sandic Primosols, Calci-Orthic Aridosols, Siltigi-Otrthic Anthrosols, and Ustic Cambosols) in the marginal farmland in the oasis of the middle Hexi Corridor region and was used to determine the characteristics of soil aggregates. The composition of dry- and wet- sieved aggregates and the physical and chemical properties (including soil particle distribution, soil organic carbon (SOC), calcium carbonate (CaCO3), and oxides of Fe3+ and Al3t) of the selected soils were analyzed. The results show that soil particle size distribution is dominated by fine sand fraction in most of soils except Ustic Cambosols. Soil organic carbon concentration is 5.88±2.52 g kg-1 on average, ranging from 4.75 g kg-1 in Ari-Sandic Primosols to 10.51 g kg-1 in Ustic Cambosols. The soils have high calcium carbonate (CaCO3) concentration, ranging from 84.7 to 164.8 g kg-1, which is increased with soil fine particle and organic carbon content. The percentage of　＞0.25 mm dry aggregates ranges from 65.2% in Ari-Sandic Primosols to 94.6% in Ustic Cambosols, and large dry blocky aggregates (＞5 mm) is dominant in all soils. The mean weight diameter of dry aggregates (DMWD) ranges from 3.2 mm to 5.5 mm. The percentage of ＞0.25 mm water-stable aggregate is from 23.8% to 45.4%. The percentage of aggregate destruction (PAD) is from 52.4% to 66.8%, which shows a weak aggregate stability. Ari-Sandic Primosols has the highest PAD. The distribution and characteristics of soil aggregates are in favor of controlling soil wind erosion. However, the stability of aggregate of all soils is weak and soils are prone to disperse and harden after irrigation. The mass of macro-aggregates and DMWD are positively significantly correlated with the contents of soil clay and silt, soil organic carbon (SOC), CaCO3, and oxides of Fe3+ and A13+. Soil fine silt and clay, SOC and CaCO3 are important agents of aggregation in this region, and the effect of SOC and CaCO3 on aggregate stability is more significant than that of soil silt and clay. Converting cropland to alfalfa forage land can increase SOC concentration, and in turn, enhance the formation of aggregates and stability. For the marginal farmlands in this fragile ecological area, converting cropland to alfalfa grassland or performing crop-grass rotation is an effective and basic strategy to improve soil structure and quality, to mitigate soil wind erosion, and to enhance oasis agricultural sustainability.     

我国冬油菜典型种植区域土壤养分现状分析

【目的】明确当前生产条件下我国长江流域冬油菜典型种植区域土壤肥力现状,尤其是土壤中微量元素养分含量,以期为冬油菜合理施肥提供参考。【方法】于2018年4—5月在我国长江流域14个省（市）冬油菜典型种植区域采集油菜收获后耕层土壤样品430个,测定土壤基础理化性质（土壤有机质、全氮、速效磷、速效钾和pH）以及中微量元素（有效钙、镁、硫、铁、锰、铜、锌和硼）含量,参考第二次全国土壤普查以及油菜种植土壤速效磷、速效钾和有效硼的分级指标,明确我国长江流域冬油菜主产区油菜种植土壤养分现状,并分析了不同区域（长江上游、中游和下游）、种植制度（水旱轮作油菜和旱地油菜）和产量水平（<2 000 kg·hm ^-2、2 000—3 000 kg·hm ^-2和>3 000 kg·hm ^-2）下油菜种植土壤的养分分布特征。【结果】长江流域冬油菜典型种植区域耕层土壤有机质、全氮、速效磷、速效钾、pH、有效钙、有效镁、有效硫、有效铁、有效锰、有效铜、有效锌和有效硼平均含量分别为25.9 g·kg ^-1、1.47 g·kg ^-1、27.5 mg·kg ^-1、131.1 mg·kg ^-1、6.04、2 436.1 mg·kg ^-1、225.7 mg·kg ^-1、22.6 mg·kg ^-1、212.3 mg·kg ^-1、89.7 mg·kg ^-1、3.84 mg·kg ^-1、4.03 mg·kg ^-1和0.45 mg·kg ^-1。超过2/3田块土壤有机质和全氮含量处于中等及以上;土壤速效磷处于丰富、适宜和缺乏的比例各占1/3;而有63.8%田块土壤速效钾处于缺乏状态。对于土壤中微量元素,土壤有效铁、有效锰和有效铜含量均处于中等及以上,有效钙和有效锌有8.4%和12.2%处于缺乏状态,而土壤有效镁、有效硫和有效硼处于缺乏的比例则分别为24.2%、36.0%和83.5%。长江流域上、中和下游冬油菜典型种植区域土壤养分状况不同,但各区域各养分的分布趋势相同。水旱轮作和旱地油菜种植土壤养分状况存在明显差异,水旱轮作油菜种植土壤有机质、全氮、有效硫、有效铁、有效铜和有效锌含量明显高于旱地油菜。不同产量水平下油菜种植土壤养分特征略有不同,高产（>3 000 kg·hm ^-2）油菜种植田的土壤速效钾、有效钙、有效镁和有效硼含量明显高于低产（<2 000 kg·hm ^-2）油菜田。【结论】整体而言,我国长江流域冬油菜典型种植区域土壤养分含量呈上升的趋势,但土壤速效钾和有效硼缺乏的比例仍较大,有效镁和有效硫成为潜在的限制因子,因此在当前我国长江流域冬油菜生产中,应重视化肥的合理施用,做到稳施氮肥,增施钾肥和硼肥,局部区域如云南西部、广西北部和湖南南部应适当减少磷肥的投入,而在广西北部、湖南南部和江西北部同时应关注硫肥和镁肥的施用。     

上实东滩生态园区土、水综合评价

为明确盐渍土改良利用方向,对上实东滩生态园区土壤、地表水、地下水多项理化性质进行了测定分析。结果表明,其土壤质地为壤质土;土壤碱化严重,酸碱度集中于8.0~8.5;土壤电导率较高,集中于0.2~0.6mS/cm,水溶性盐分含量较高,集中于0.6~3.68g/kg,且以氯化钠为主,仍有一定程度的盐渍化,土壤盐化程度与地下水矿化度呈正相关;土壤有效磷集中在20mg/kg以下,有机质集中在2g/kg以下,土壤主要养分总体含量较低,且其含量随土壤深度增加而降低;硝态氮含量正常,均在1~51 mg/kg范围内;综合评价得出,园区土壤以3类土为主,占比58.06%。研究结果对滨海地区的盐渍土管控和农业生态园建设有一定的指导意义。