不同土水比土壤浸提液与饱和泥浆电导率的比较研究

针对饱和泥浆调制时饱和点的不确定性及其电导率测定的不稳定性等问题,为了统一和准确地表征暗管改碱的盐碱土盐渍化程度,采用室内化验与统计分析的方法,系统比较研究了饱和泥浆所需水量与饱和土壤溶液所需水量及其电导率和全盐与土水比1︰5、1︰2.5、1︰1、1︰0.5系列的相关和换算关系。研究结果表明:在黄河三角洲盐碱土(氯化物类型)区,可采用通过计算土壤孔隙度得到的饱和土壤溶液含水量来定量确定原来定性判定饱和点的饱和泥浆含水量,以饱和土壤溶液电导率可完全代替饱和泥浆电导率;饱和泥浆电导率数值和全盐含量均不是土水比1︰5、1︰2.5、1︰1、1︰0.5系列中的最高值,但均与其存在极显著的相关关系,饱和泥浆电导率与土水比1︰5土壤浸提液的电导率、饱和泥浆全盐含量与土水比1︰0.5全盐含量相关性最高,可分别用最佳拟合回归函数模型进行换算:一元线性函数模型Ece=2.042 8×EC1︰5+0.089 5、一元二次函数模型Tse=0.064 1×(TS1︰0.5)2?0.059×TS1︰0.5+0.397 9。     

不同土地利用条件下的城市土壤电导率垂直分布特征

电导率在探讨城市土壤基本化学性质、盐渍化程度、肥力质量特征和污染特点方面有重要意义.利用电导率仪测定南京市道路、绿地和菜地土壤电导率,并通过描述性统计分析、垂直分布特征探讨和电导率与其他土壤理化指标的相关分析及在此基础上展开的逐步回归和通径分析,研究土地利用方式对城市土壤电导率垂直分布的影响.结果表明:南京市主城区土壤电导率最高值0.641 mS/cm,并无盐渍化现象,但由于受人为干扰的程度存在较大差异,道路和菜地土壤电导率变异系数较大(分别为65.40%和72.60%),而绿地土壤电导率变异系数较小(21.05%);土壤电导率的垂直分布具有各自鲜明的特点:道路土壤电导率表层较高,表层以下无一定规律;菜地土壤自耕作层向下电导率逐渐降低;绿地土壤无明显趋势.土壤电导率影响因素在不同的土地利用方式间也存在差异:道路土壤电导率受频率磁化率和活性铁等控制,绿地土壤电导率受总有机碳和活性铁等控制,而菜地土壤电导率受总有机碳、全磷和游离铁等控制.由于所研究影响因子仅能解释电导率总变异的40.72%～58.86%,今后还需从城市土壤离子组成等方面进一步深入研究土壤电导率的影响因子.     

Gypsum and Texture Effects on the Estimation of Saturated Paste Electrical Conductivity by Two Extraction Methods

Abstract

Texture and salt type can influence the relationships between saturated paste electrical conductivity (EC_e) and EC of other soil/water ratios. The objectives of this study were to develop and validate relationships among EC_e, EC_1∶2, and EC_1∶5 for soils in Yazd Province, and evaluate the effects of texture and gypsum on those relationships. Two hundred thirty‐six soil samples were collected, of which 200 were used to develop and 36 were used to validate the models. The soils were divided into two textural categories, coarse and fine, and two categories, with and without gypsum. The 1∶2 procedure predicted EC_e of slightly more than 1∶5. Gypsum content had stronger impact on the accuracy of models in predicting EC_e than texture. The EC_e=4.0723EC_1∶2?5.7135 and EC_e=3.5142EC_1∶2+0.7615 models are recommended for soil with and without gypsum, respectively. The methodology can be implemented in any other region, particularly if gypsum is present.     

Physical,Chemical and Biological Properties of an Accelerated Cassava Based Compost Prepared Using Different Ratios of Cassava Peels and Poultry Manure

Monitoring the physical, chemical and biological properties during accelerated composting enables concise determination of its stability and maturity. Determination of physical parameters such as pH, moisture and temperature, chemical parameters such as total nitrogen (N), phosphorus (P), potassium (K), organic matter and humic acid as well as biological parameters such as microbial count and carbon dioxide (CO₂) evolution was carried out during a four (4) week composting period, The trend observed for pH showed the mesophilic and thermophilic phases and a similar trend was observed for the compost temperature. Intermittent increase and decrease was observed for total N, P, K as well as for the fungal and bacterial population. A direct relationship was observed among the bacterial population, CO₂ evolution and humic acid. However, composting for four (4) weeks produced a stable compost, which was evident through the physical observation of the final product and the results obtained for the chemical and biological parameters.     

Performance of Soil Electrical Conductivity and Different Methods for Mapping Soil Data from a Small Dataset

The performance of different methods for making soil maps from a small dataset was assessed. Soil samples obtained at five different depths were taken from 39 locations within an arable field in Sweden and analysed for clay content, soil organic matter content, pH (H₂O), K-HCl, P-AL, K-AL and Mg-AL. Detailed and densely sampled soil electrical conductivity (EC) data with a distinct border between two different regions was used for dividing the field into two zones. Averages from these zones gave better prediction for most variables than interpolation without respect to the border. With the border taken into account, cokriging with EC as a covariable improved the prediction, whereas the improvement with ordinary kriging and inverse distance weighting (IDW) was insignificant. Direct interpretation of EC by a simple linear regression model gave reasonable predictions for clay content. In general, even the simplest interpolation method improved the prediction compared to field average.     

Sequential Extraction of Heavy Metals Found in MSW-Derived Compost

Compost standards usually contain maximum permissible levels of heavy metals. These almost always refer to “total” concentrations. However, more relevant to environmental impact due to compost usage are “leachable” concentrations. This study utilized a sequential extraction technique to evaluate availability of heavy metals present in an MSW-derived compost. Five fractions (A-E) were obtained, the result of progressively stronger leaching solutions. Profiles of fraction distributions varied drastically from metal to metal. Manganese and zinc had very significant amounts in fractions B and C, whereas copper and chromium were present almost entirely in fractions D and E, respectively. Comparisons with other leachate methods are offered.     

不同微生物促腐剂在鸡粪好氧堆肥中的应用研究

为了研究不同微生物促腐剂在好氧堆肥上的应用效果,以鸡粪和玉米秸秆为原料,添加3种不同的微生物促腐剂,在好氧条件下进行了高温堆肥试验。在堆肥的不同阶段测定物料的有机质、全氮、全磷、全钾、种子发芽指数及温度,研究3种促腐剂应用过程中以上指标的差异以及变化趋势。结果表明,添加微生物促腐剂可以加速鸡粪腐熟,添加秸秆调节物料的碳氮比(25/1)可以更好地促进菌剂发挥作用,添加微生物促腐剂M2的处理较对照提前8d达到高温期,养分保存效果优于菌剂M1和M3,全氮、全磷、全钾的最高保存率分别为36.36%,8.26%,23.53%。     

蔬菜种子的电传导和介电特性

本文介绍一种能在任意频率下测定种子电阻率和介电常数等电参量的测试系统和方法,研究了蔬菜种子的含水量和测试频率对种子电传导和介电特性的影响,莸得相互之间的回归方程。     

不同微生物菌剂对鸡粪高温堆腐的影响

以鸡粪和玉米秸秆为原料,采用好氧堆肥的方式,研究添加三种不同微生物菌剂对鸡粪高温腐熟效果的影响,探索有益微生物菌剂在畜禽废弃物高温堆肥中的作用。分析了堆肥不同时期各处理的堆温、pH值、种子发芽指数、水溶性铵态氮、水溶性有机氮、全氮、有机碳的变化。结果表明,在添加玉米秸秆调节物料碳氮比(25/1)的情况下,添加本研究中所采用的微生物菌剂可以迅速降低物料对种子发芽指数的影响,使发芽指数在21 d内达到80%以上,较对照提高45.52%;对水溶性铵态氮的转化和水溶性有机氮的形成都有明显的促进作用,腐熟堆肥的氮素保持提高25.46%;明显提高堆肥初期发酵温度,使堆体在第2 d达到高温阶段,并持续7 d以上,最高温度比对照高4.8℃,满足堆肥无害化卫生要求,大大缩短堆腐周期。综合多项指标分析,接种菌剂M2对促进有机碳的分解、有机氮的形成和提高腐熟效率更为有利。     

施用石膏对苏北滩涂盐渍土浸提液电导率换算关系的影响

采用土壤饱和浸提液、土水比1︰1浸提液和土水比1︰5浸提液3种方法,测定了苏北滩涂地区施用石膏改良土壤样品的电导率和p H。结果表明:未用石膏改良的土壤饱和浸提液电导率与土水比1︰1及1︰5浸提液电导率之间存在显著相关关系,相关系数分别为0.988和0.979;在施用石膏情况下,土壤饱和浸提液和土水比1︰5浸提液电导率均随石膏添加有一定程度升高,且二者之间仍有良好的线性相关关系,其换算关系为:ECe=1.42+6.86×EC1︰5(r=0.980**);且施用石膏能显著改善土壤碱化程度,降低土壤p H。本实验研究条件下,建议研究区石膏施用量为3 g/kg(即0.6 kg/m2)。     

猪粪堆肥提取液对棉花生长和养分代谢的影响

为了研究猪粪堆肥提取液的促生效果,通过盆栽试验研究了分别浇施以0.5 mol.L-1硫酸钾和水为浸提剂提取的猪粪堆肥提取液（分别简称为K和W）对棉花生长的影响。结果表明：（1）施用K和W能显著增加棉花植株的株高、果枝数、蕾数、棉铃数。籽棉产量分别比清水对照（CK）增加了2.30倍和1.86倍,但是K和W两者之间差异不显著。（2）棉花现蕾期、花铃期和吐絮期的植株生物量分别比CK增加了71.4%和52.9%、114.2%和83.5%、106.1%和90.5%,氮磷钾累积量与CK比较显著增加。K处理的棉花在现蕾期和花铃期的植株干重显著高于W处理。（3）从现蕾期到吐絮期,棉花植株功能叶硝酸还原酶活性随之增加,而可溶性蛋白含量却随之降低。与CK比较,施用K和W能显著增加不同时期棉花植株功能叶片硝酸还原酶活性和可溶性蛋白含量。花铃期K处理的功能叶硝酸还原酶活性显著高于W处理。K处理和W处理的棉花功能叶可溶性蛋白含量分别比CK增加了1.24倍和3.01倍（现蕾期）、59.1%和40.0%（花铃期）。（4）施用两种猪粪堆肥提取液,在一定程度上都能增加棉花叶片可溶性糖和淀粉含量,但各处理间差异不显著。上述结果表明,猪粪堆肥提取液能明显改善棉花植株的生长发育,显著增加棉花产量,可以作为优质有机液体肥料。     

电导率法在土壤盐渍化中的改进和应用进展

土壤盐渍化是常见的地质灾害之一,对土壤盐分状况及盐渍化程度的空间分布特征进行了解是有效治理的前提条件。电导率法作为一种快速稳定测定土壤盐分时空分布特性的方法被广泛应用于土壤盐渍化研究中。土壤溶液电导率(ECw)、土壤浸出液电导率(ECe)及土壤表观电导率(ECa)都可以对土壤盐渍化程度进行量化,土壤溶液电导率(ECw)可以通过原位取样器和盐分传感器进行测量,通过制备饱和土浆则可以对土壤浸出液电导率(ECe)进行测量,电阻率法和电磁感应法则可以测定土壤的表观电导率(ECa)。本文就不同电导率法的测量原理及实际测量对象、常用技术设备、优缺点进行综述。为更好的理解电导率法在土壤盐渍化中的应用提供参考     

Biological,Physicochemical, and Spectral Properties of Aerated Compost Extracts: Influence of Aeration Quantity

The goal of this experiment was to investigate the effect of aeration quantity (0, 11, 33, 55, and 77 L·min^?1) on the growth of aerated compost extracts from a pig manure–straw compost. When the aeration quantity was 11 L·min^?1, lettuce root growth enhancement of normalized compost extracts was at a maximum. As the aeration quantity increased, the total water-soluble organic carbon (TWSOC), total nitrogen (TN), total phosphorus (TP), humic carbon (humic C) content, and humification degree of compost extracts improved gradually. No differences in functional group structure were found among the aerated compost extracts. The positive root growth could be attributed to physicochemical and spectral characteristics, such as TN content, humic substances content, humification, aromaticity, and the low content of carboxyl groups. In conclusion, the aeration quantity of 11 L·min^?1 was suitable for the production of aerated compost extracts, which obtained much greater promotion growth.     

不同过磷酸钙添加量对蔬菜废弃物堆肥的影响

试验研究了不同过磷酸钙添加量对蔬菜废弃物堆肥腐熟进程的影响。结果表明,添加过磷酸钙能够提高堆体温度,其中添加量为堆肥物料干重10.26%时的最高温度值最高,为64.33℃。堆肥结束时,添加过磷酸钙对各堆肥处理的C/N值无显著影响,但降低了堆肥物料的pH值,提高了电导率,其中添加量介于物料干重4.10%和10.26%时的EC值显著高于CK处理(P0.01);添加量低于物料干重10.26%时的GI值均显著高于CK处理(P0.01),其中添加量为物料干重2.05%(S5处理)时的值最大,为105.61%。添加过磷酸钙显著降低了堆肥的氮素损失率(P0.05),其中添加量为物料干重2.05%时的氮素损失率最低,仅为23.94%,且此添加量下的产投比最大,为3.93。本试验条件下,添加过磷酸钙可显著提高堆肥腐熟度,显著降低堆肥物料的氮素损失率,其适宜添加量为物料干重的2.05%。     

洛惠渠灌区典型样区地下水位与电导率关系研究

洛惠渠灌区位于陕西省关中平原东部,由于不同区域的积盐过程不完全相同,针对洛惠渠灌区地下水的盐分变化情况,采用Morlet小波分析了灌区76#井的电导率和水位周期变化规律。结果表明,电导率变化和水位变化有很好的相关关系。小尺度上,水位变化周期和电导率的基本相同;大尺度上,水位约为电导率变化周期的2倍。两者变化存在明显的逆向位。该地区含有大量可溶性盐层,地下水电导率本底值较高。由于大气降水补给,电导率值随水位变化在一定的范围内波动。研究结果可为该灌区地表生态环境的改善提供依据。     

Space-Time Modeling of the Electrical Conductivity of Soil in a Geothermal Zone

The aim of this study was to generate models to predict the salinity of the soils in the geothermal zone which is located in Michoacán, México, over space and time. Systematic sampling was performed at locations 400 m apart with a sampling period every 48 days. At each site, two soil samples, from depths of 0–30 cm and 30–60 cm, were collected and analysed in laboratory. Regression-Kriging was used to make spatial predictions of the electrical conductivity of soil (ECs). Spherical and Gaussian theoretical models fit the experimental semivariograms. The results showed that the soil samples ranged from slightly saline (2.1–4 dS m^?1) to strongly saline (8.1–16 dS m^?1). In addition, the ECs was greater at a depth of 30–60 cm than it was at a depth of 0–30 cm. The ECs decreased from more than 8.0 dS m^?1 to less than 4.0 dS m^?1 after the first sampling period.     

施用不同堆肥对小白菜根系生长和氮素吸收的影响

通过盆栽试验,研究施用猪粪堆肥、中药渣堆肥和菇渣堆肥对小白菜根系生长、氮素积累量和氮素干物质生产效率的影响。结果表明:(1)各施肥处理小白菜根系鲜(干)重、体积、表面积、平均直径和根系总长高于对照;(2)猪粪堆肥、菇渣堆肥处理小白菜地上部氮素积累量高于对照,中药渣堆肥处理小白菜地上部氮素积累量低于对照;(3)中药渣堆肥处理小白菜氮素干物质生产效率高于对照,猪粪堆肥、菇渣堆肥处理小白菜氮素干物质生产效率低于对照。通过试验发现,猪粪堆肥处理增加氮素供应可以促进小白菜根系生长,增加小白菜地上部氮素积累量,其根系形态指标与氮素积累量相关性较低,氮素干物质生产效率低;含氮量低的菇渣堆肥、中药渣堆肥处理小白菜通过扩大根体积、表面积等来加强对氮素的吸收,根系形态指标与植株氮素积累量有较高的相关性,氮素干物质生产效率高。氮素积累量与氮素干物质生产效率呈极强的负相关。