民勤湖区表层土壤养分的空间异质性

利用地统计学方法研究了民勤绿洲湖区表层土壤养分碱解氮、速效磷和速效钾的空间异质性.结果表明:绿洲、过渡带和荒漠三种景观下表层土壤中氮磷钾含量都呈现出“丰氮、富钾、贫磷”的特征;碱解氮与速效磷的变异系数在绿洲区最小,荒漠区最大,而速效钾在荒漠区最小,过渡带最大,但都属于中等变异;从绿洲到荒漠,碱解氮、速效磷呈U型分布特征,而速效钾为倒U型分布特征.碱解氮的最佳拟合模型为Exponential,速效磷为PentaspHerical,速效钾为Tetrasherical;氮和磷的富集区位于绿洲区,而速效钾在过渡带上出现富集中心.土壤的养分元素含量除了与成土母质的元素有关外,人类活动的影响也是非常重要的因素.     

陕北神木矿区土壤颗粒体积分形特征及意义

土壤由母质风化而成,土壤的颗粒组成继承了母质的许多特征,分形特征便是其中之一.土壤颗粒分形特征不仅影响土壤的水力状况和肥力特征,而且与土壤侵蚀和退化状况直接相关.利用MS 2000激光粒度分析仪,测定神木矿区凉水井煤矿、四道沟煤矿和红碱淖原生态保护区3个样区60个土样的粒径分布状况,运用土壤体积分形模型计算土壤颗粒体积...     

新疆伊犁盆地昭苏黄土剖面稀土元素特征

对晚更新世以来,伊犁地区与典型黄土高原地区黄土的稀土元素（REE）特征差异研究表明,伊犁盆地黄土剖面的REE特征不仅在含量上与典型黄土区的相似,分馏特征也基本相似,呈斜“L”型的分布模式,均发生轻、重稀土分异,分布曲线为负斜线,表现出中度的Eu负异常,Ce异常不明显,意味着晚更新世以来,不同地区黄土的物质来源具有一定的相似性。研究还发现,伊犁地区与黄土高原地区的稀土元素特征存在细微差异,昭苏黄土平均的稀土元素总量略高于昭苏古土壤平均值,与典型黄土区不同,这可能是由伊犁地区粉尘来源及其沉积环境的差异所致,且晚更新世以来不同区域黄土剖面REE特征参数三角图解也证实了这点。     

景泰县旱地、旱砂地养分特征比较研究

选择景泰县寺滩乡附近相邻旱地和旱砂地作为研究对象,对两块样地土壤pH值、有机质、N、P含量进行测定和分析。结果表明:1)两块样地表层土壤养分特征表现为缺N、多P、富K,旱砂地缺N更严重,甚至低于灰钙土碱解氮含量平均值,旱地各养分含量高于景泰县平均土壤养分状况。2)从两个土壤剖面来看,全N和碱解N受有机质影响显著,三者的变化趋势较一致;速效P受全P影响显著,这点在旱砂地表现更突出,而速效K含量主要与土壤母质及其风化程度有关,这在旱地表现的更突出。旱地土壤呈碱性环境,其土壤养分有效性受到抑制。3)有机质与N、P、K显著正相关,说明增加有机肥可以有效改善土壤肥力,但要了解土壤养分本底值,结合农作物对养分种类及数量的需求做到科学、合理供肥。     

铁门关市土壤硒含量分布特征及影响因素探讨

为探讨新疆铁门关市土壤硒含量、空间分布特征和影响因素,系统采集分析了3916件表层土壤样品和59件上游山体岩石样品,测定了岩石样品硒和土壤样品硒、pH、水溶性盐总量、阳离子交换量、有机质、全氮磷钾和重金属元素等16个分析指标,采用皮尔逊相关性及主成分分析对土壤类型的指标进行综合研究。结果表明：研究区表层土壤硒含量均值为0.36mg·kg^-1,富硒土壤面积113.12km²,无硒中毒和重金属污染土地。土壤硒元素主要来源于石炭系下统野云沟组灰岩、粉砂岩和砂岩,除了受成土母质、土壤类型的影响外,还受有机质、阳离子交换量、全氮磷钾等肥力指标的影响。对土地利用类型现状的研究发现,铁门关市具有提升富硒土地合理开发利用的潜力。     

陕西周原地区全新世黄土-古土壤序列风化程度研究

通过对周原LC全新世黄土-古土壤剖面的元素含量分布及其化学风化程度和元素迁移特征的研究。结果发现:古土壤S₀的CIA和Rb/Sr值高于黄土L₀,Na/K比低于黄土L₀,指示其风化程度强于黄土L₀,形成时期气候比黄土堆积时期温暖湿润;黄土风化成壤过程中,Si,K和Fe相对富集,而Ca,Na,Mg和Ti则迁移淋失,呈现Ca>Na>Mg>Ti>Al>Si>K>Fe的迁移序列;全新世剖面化学风化程度处于脱Na和Ca阶段或早期去K阶段。     

不同施肥方式对垄沟灌溉水氮分布的影响

采用室内土箱试验,研究了垄沟施肥、垄底施肥和垄顶施肥方式和垄沟灌溉对水分、硝态氮和铵态氮分布的影响.结果表明,土壤水分最先从沟部入渗,垄沟表层土壤剖面迅速吸湿,在土壤水分再分布过程中,垄部土壤剖面含水量明显增加;但不同施肥方式对土壤水分含量不存在显著影响;土壤N03--N的分布与水分的分布类似,施肥方式对土壤N03--N含量存在显著影响,垄顶施肥和垄底施肥可以有效减少土壤N03--N的淋溶,至40 cm土层深度土壤N03--N含量仅为7 mg·kg-1左右,在剖面上的分布较为集中;然而,由于土壤表面的吸附作用,土壤NH4+-N在施肥区累积,出现峰值,再分布过程中垄顶施肥处理比垄底施肥处理土壤NH4+-N含量高.     

辽南石槽剖面红色风化壳地球化学特征初步分析

通过对元素含量分布特征、元素活化情况以及化学风化强度的分析,研究辽南石槽剖面红色风化壳的地球化学特征,为认识不同地区红色风化壳风化特征的空间差异提供初步依据。结果表明:石槽剖面红色风化壳的化学组成以SiO_2、Al_2O_3和Fe_2O_3为主,化学风化过程中Fe、K、Na、Mg和Ca发生不同程度的迁移淋失,而Al、Si相对富集。微量元素含量平均值排序为MnO>ZrO_2>Cr_2O_3>Rb_2O>ZnO>NiO>SrO>CuO,Ni、Cu、Zn、Sr、Mn等微量元素强烈亏损,淋失程度随风化程度的增强而增强。石槽剖面红色风化壳发育在较温暖、湿润的气候条件下,处于脱Ca、Na富Al的中等化学风化阶段。     

新疆孔雀河北岸湖相沉积物稀土元素丰度特征及其古气候意义

通过对罗布泊LX02剖面孔沉积物稀土元素丰度、分布模式及稀土总量的分析,结合沉积物中烧矢量和粒度参数的变化特征,探讨了稀土元素纵向变化与气候环境之间的关系。结果表明:罗布泊沉积物中稀土元素丰度值较高,平均值为140.0402μg/g,总体上以较湿润的环境为主导,化学风化作用较强。同时,沉积物中轻重稀土元素比值约为9.5,轻稀土含量明显高于重稀土含量,为明显的右倾斜型,Eu为中度负异常,Ce绝大部分为微弱的负异常的稀土配分模式。稀土元素含量与粒度和烧矢量之间存在较好的相关性,分析表明,沉积物中∑REE高值段指示暖湿气候环境,∑REE低值段代表冷干气候环境。根据稀土元素分布与沉积环境的关系,重建了72.4～51.0ka BP期间罗布泊地区经历了4次较大的冷干-暖湿-冷干-暖湿的气候演化过程,从而得出在干旱半干旱地区的罗布泊沉积物中稀土元素对古气候变化具有良好的指示作用。     

黄土丘陵沟壑区人工农田土壤钾素特征研究

通过土样分析,利用统计分析法系统研究了黄土丘陵沟壑区人工农地——坝地和梯田的土壤钾素含量、相关性、垂直和时空分异特征。研究结果表明:坝地和梯田钾素分布严重失衡;表层速效钾平均含量坝地属"中等",梯田属"缺乏";表层全钾平均含量坝地属"较高",梯田为"中等";缓效钾平均是速效钾的7.58倍(坝地)和11.06倍(梯田),但转化率较低;矿物钾平均占全钾的95.71%(坝地)和95.16%(梯田),却难以被作物利用。土壤各形态钾素间都呈极显著正相关,并受土壤有机质、CEC、pH值和颗粒组成的影响。表层与下层间的速效钾、坝地和梯田间的缓效钾都有极显著差异,但黄土母质土壤钾素整体分布均一;坝地速效钾沿剖面向下含量增加,且整体高于梯田;坝地因高耗钾作物玉米而导致缓效钾含量低于梯田。土壤有效性钾、速效钾和缓效钾在时间动态上都表现为先增后降,分水岭年限坝地约在40 a,梯田约在30 a。     

Rates of chlorsulfuron degradation in three Brazilian oxisols

The degradation of chlorsulfuron was studied in laboratory experiments in three oxisols from south and south–east Brazil. Three soil profiles were sampled by horizon, and classified according to USDA soil taxonomy and the Brazilian system. Degradation assays were made to evaluate the influence of temperature, humidity and liming on chlorsulfuron decomposition. Further experiments were set up to study enhanced biodegradation. Abiotic degradation was also studied in sterile soils, to evaluate, by comparison with non–sterile soils, the role of microorganisms in degradation. The degradation always followed first–order kinetics and was generally faster in samples from A than B horizons. An increase in temperature (from 25 to 40°C) increased chlorsulfuron degradation. Further, an increase in moisture content increased chlorsulfuron degradation in samples from the A horizons of all soils, whereas for two out of three soils, degradation in samples from the B horizon was greater at lower water content. The biotic contribution to degradation was significant only for the soil with higher fertility. Soil liming significantly increased chlorsulfuron half–life in all samples. Significant enhancement of degradation (decrease in half–life on reapplication) was observed only in soil from A horizons, where a higher microbial activity was likely.     

西安郊区农耕地和大棚菜地土壤重金属迁移的对比研究

以西安污灌区典型大棚菜地和附近农耕地土壤为研究对象,在不同土壤剖面上对重金属As、Cr、Cu、Pb、Zn和Ni的分布进行了测定和分析。结果表明:在0~20 cm土层农耕地土壤重金属Cr、Cu、Pb、Zn、Ni的含量均高于大棚菜地,分别高出53.1、16.7、20.5、151.2和3 mg/kg,同农耕地相比,温室大棚更有利于土壤表层重金属的迁移,且对Zn、Cr、Pb、Cu等元素的迁移程度较明显。认为在西安污灌区发展大棚花卉,可以有效减少污灌区土壤表层重金属的含量。     

宁夏不同地区农田土壤矿质氮的空间变异特征

在宁夏灌区和旱区共计选定肥力水平不同的30块农田,分别采集了0~120 cm深土壤剖面样品和小麦植株样品,测定了土壤铵、硝态氮含量和小麦地上部含氮量,分析了土壤矿质氮的空间变异性及其与小麦吸氮量的关系。结果表明,在0~120 cm深土壤剖面中,NH4-N、NO3-N和矿质氮含量及其累积量,灌区土壤显著高于旱区土壤,测点之间存在极显著差异,变异系数相当高。但在土层间不论灌区还是旱区变化不明显,在剖面上下分布比较均匀。矿质氮含量在土层间存在着正相关。在0~120 cm深土壤剖面中,矿质氮累积量在灌淤土、黑垆土、黄绵土和灰钙土间差异较大,平均分别为370.0、155.1、117.5和61.0 kg/hm2。其累积量与小麦籽粒产量、生物学产量、地上部总吸氮量之间呈极显著正相关,表明土壤较深层次的矿质氮对作物吸氮量也具有重要贡献。     

Responses of microbial activities and soil physical-chemical properties to the successional process of biological soil crusts in the Gurbantunggut Desert,Xinjiang

Biological soil crusts(BSCs) are capable of modifying nutrient availability to favor the establishment of biogeochemical cycles. Microbial activities serve as critical roles for both carbon and nutrient transformation in BSCs. However, little is known about microbial activities and physical-chemical properties of BSCs in the Gurbantunggut Desert, Xinjiang, China. In the present research, a sampling line with 1-m wide and 20-m long was set up in each of five typical interdune areas selected randomly in the Gurbantunggut Desert. Within each sampling line, samples of bare sand sheet, algal crusts, lichen crusts and moss crusts were randomly collected at the depth of 0–2 cm. Variations of microalgal biomass, microbial biomass, enzyme activities and soil physical-chemical properties in different succession of BSCs were analyzed. The relationships between microalgal biomass, microbial biomass, enzymatic activities and soil physical-chemical properties were explored by stepwise regression. Our results indicate that microalgal biomass, microbial biomass and most of enzyme activities increased as the BSCs developed and their highest values occurred in lichen or moss crusts. Except for total K, the contents of most soil nutrients(organic C, total N, total P, available N, available P and available K) were the lowest in the bare sand sheet and significantly increased with the BSCs development, reaching their highest values in moss crusts. However, pH values significantly decreased as the BSCs developed. Significant and positive correlations were observed between chlorophyll a and microbial biomass C. Total P and N were positively associated with chlorophyll a and microbial biomass C, whereas there was a significant and negative correlation between microbial biomass and available P. The growth of cyanobacteria and microorganism contributed C and N in the soil, which offered substrates for enzyme activities thus increasing enzyme activities. Probably, improvement in enzyme activities increased soil fertility and promoted the growth of cyanobacteria, eukaryotic algae and heterotrophic microorganism, with the accelerating succession of BSCs. The present research found that microalgal-microbial biomass and enzyme activities played important roles on the contents of nutrients in the successional stages of BSCs and helped us to understand developmental mechanism in the succession of BSCs.     

新疆荒漠与半荒漠土壤微量元素的土类分异与地域分布趋势

本文研究了新疆荒漠与半荒漠土壤微量元素的土类分异、地域分异及微量元素在土壤剖面中的分布,并对土壤样品的误差分布进行了估计。研究表明,除风沙土外,各土类间微量元素含量差异不大;北疆土壤中大部分元素含量高于南疆;山地土壤微量元素含量高于平原荒漠与半荒漠地区土壤;微量元素在土壤剖面中的分异不明显。     

Leaching of Alachlor from Alginate-Encapsulated Controlled-Release Formulations

The mobility of alachlor from alginate-encapsulated controlled-release (CR) formulations was investigated in two contrasting soil profiles. Two CR formulations of alachlor were prepared with the following components (1) base—sodium alginate+kaolin+‘Tween’ 20 (1+10+0·5 by mass) and (2) base+40 g kg⁻¹ linseed oil. These were compared to technical grade alachlor and to a commercial alachlor EC formulation (‘Lasso’ 4EC). All herbicide treatments were labeled with [¹⁴C]alachlor and were applied to duplicate soil columns that were composed of a surface and a subsoil horizon. Each horizon was packed to a depth of 12·5 cm, giving a total column length of 25 cm. The columns were leached with 21 cm (420 ml) to 30 cm (600 ml) of 0·01M calcium chloride for a period of 7 to 10 days. Alachlor leaching from the EC formulations was the same as that from the technical material in both soils: 33% in the Evesboro and 10% in the Conover soil. The CR-Oil formulation leached 4 and 2% of the applied [¹⁴C]alachlor, compared to 12 and 3% for the CR-N formulation for the Evesboro and Conover soils, respectively. The CR-Oil formulation also increased the amount of [¹⁴C]alachlor retained in the soil surface horizon (105–114%), compared to CR-N (39–45%), technical material (14–23%) and EC (12–17%).     

金昌城郊耕作土壤重金属Cu、Zn、Ni的分布规律

以干旱区绿洲金昌城郊耕作土壤为供试土壤,采用全量分析法和Tessier五步连续提取法研究了六个典型土壤剖面重金属Cu、Zn和Ni的总量以及形态纵向分布规律。结果表明:重金属Cu和Ni表聚现象明显,表层至下,其浓度先减少后稳定,两种元素在剖面中的迁移距离相近,基本在45cm附近;Cu和Ni化学行为相似,反映了Cu和Ni来源相同;Zn的总量分布没有明显的规律性。在土壤剖面中,Cu、Ni有形态变化层位,0-45cm有机态Cu>残渣态Cu>铁-锰氧化态Cu,碳酸盐态Cu>可交换态Cu;Ni的铁-锰氧化态>有机态,残渣态,碳酸盐态>可交换态;45cm后Cu、Ni主要以残渣态存在;Zn在所有土层中均以残渣态为主要赋存形态。研究土壤Cu、Ni的总量及形态分布主要受人为活动影响,Zn主要受成土母岩影响。     

Migration and accumulation of heavy metals in disturbed landscapes in developing ore deposits,East Kazakhstan

This paper studied the contents of heavy metals and their accumulation in the disturbed landscapes in ore deposits of East Kazakhstan. A total of 14 sites were examined in Zyrynovsky and Tishinsk deposits and Ridder town, and 50 soil samples were taken. Results indicated that the contents of heavy metals in the soil reached the maximum permissible concentration. Emissions of the zinc plant negatively affected the soil of nearby territories. In the remediated areas, a high concentration of heavy metals was observed at a depth where the bulk soil borders the rock. Accumulation of heavy metals on the surface of the remediated areas occurred due to biological accumulation in the plant. Plants transmitted heavy elements through the root system to the upper vegetative organs, making them accumulate in the upper layers of the soil. The heavy metals migrated and accumulated from the lower layers to the surface layers of the soil. The absence of soil meso-fauna resulted in the contamination of soil by heavy metals. The analysis of water samples, taken from the waste storages and the waste waters with heavy metals in the Zyryanovsk deposit and Ridder town, revealed severe water contamination.     

30 a耕作对高寒草地土壤碳氮与颗粒组成的影响

根据青海湖流域1987—2010年5期遥感图像解译,在青海湖北部区域存在毗邻的30 a未曾变动草地和耕地。以这两类土壤为研究对象,对其0~60 cm土层的土壤总碳、土壤全氮、土壤粒度组分进行对比研究。结果表明:草地和耕地土壤总碳和全氮含量以30 cm为界,分异明显,界上草地总碳和全氮含量大于耕地,而界下两者之间差异较小。另外,草地总碳和全氮含量最大值出现在0~10 cm,耕地总碳和全氮含量最大值出现在10~20 cm。草地和耕地粒度组成上都属于砂黏壤级,其中草地粉砂和黏粒大于耕地,而砂含量小于耕地。30 cm以上,草地和耕地间土壤粒度组分差异大,30 cm以下差异小。草地土壤黏粒和粉砂组分与总碳(P0.05)、全氮(P0.01)呈显著相关,而土壤砂粒组分与其相关性不显著;耕地总碳和全氮与各土壤粒级组分之间均无显著相关性。