污水灌溉对农业环境影响的研究——以石家庄市污水灌溉区为例

通过对石家庄市污水灌溉区污水,农作物,土壤及地下水的现状调查及评价,研究了污水灌溉对农作物、土壤及地下水的影响。结果表明,石家庄市排放的污水水质为有机污染类型,硫化物污染较重,有机物污染中度、重金属类污染较轻;污水泽排污水渠两侧地下水有影响,影响范围为１００￣２００ｍ;该市已用污水灌溉农田４０年,作物（小麦、玉米）籽粒中重金属含量均应低于国家食品重金属限量卫生标准;表层土壤中重金属含量均低于国家土     

沼液灌溉对土壤质量的影响

通过田间试验研究了不同沼液灌溉量对土壤质量和生态安全的影响.结果表明在N、P、K养分相等条件下,完全沼液灌溉和与化肥配合施用均能改善土壤肥力,重金属等有害元素在国家土壤环境质量指标内,但沼液长期灌溉对土壤质量的影响还需进一步研究.     

灌溉水质对土壤化学特征和作物生长的影响

本文以灌溉水矿化度和钠吸附比为两个主要指标，组合成１６个灌溉水质处理，研究了不同灌溉水质对土壤化学性质和作物生长的影响。初步提出了引起盐害和碱害的灌溉水矿化度和钠吸附比的临界值。研究结果表明，灌溉水带入土壤的盐分在土壤中累积与淋洗交替进行。     

污水灌溉对农业环境影响的研究--以石家庄市污水灌溉区为例

通过对石家庄市污永灌溉区污水、农作物、土壤及地下水的现状调查及评介,研究了污水灌灌对农作物、土壤及地下水的彭响。结果表明,石家庄市排放的污水水质为有机污染类型,硫化物污染较重,有机物污染中度,重金属类污染较轻;污水对排污水渠两侧地下水有影响,影响范围为100～200m;该市己用污水灌灌农田40年,作物(小麦、玉米)籽粒中重金属含量均相应低于国家食品重金属限量卫生标准;表层土壤中重金属含量均低于国家土壤环境质量标准中规定的二级标准。合理灌溉污水可增加土壤有机质和全N含量。     

不同土壤施用钾肥对小麦生长和土壤钾含量的影响

本研究在人工气候室中对几种不同土壤施钾，观察其对小麦生长和土壤钾含量的影响。盆载试验结果表明，在砂土小麦植株达最高生长量的施钾量（Ｋ）为１２０ｍｇ／ｋｇ，其它土壤为６０ｍｇ／ｋｇ。钾肥施用越多，土壤有效钾化不施钾处理增加越多。同时对两种有效钾浸提测定方法进行了相关性研究，表明阳离子交换膜（ＣＥＭ）浸提的钾与醋酸铵（ＮＨ４ＯＡＣ）浸提的钾呈显著的正相关。     

关于发展农业节水灌溉的建议

本文提出了农业节水的关键是：节水的主要潜力在河水灌　区，要按农业用水需要量控制灌溉水量，要在河水灌区积极开发利用浅层地下水和微咸水，　发展井渠结合灌溉的统一管理并改革水价．     

啤酒厂废水灌溉对土壤性质的影响

通过对利用啤酒厂废水灌溉３、５年和基本不灌溉的农田土壤物理，化学性状的对比分析认为：啤酒厂废水灌溉农田可以减少废水对周围环境的污染，节省水源，有利于农业生产，啤酒厂废水中含有有机物和少量无机盐，灌溉农田可以增加土壤有机质和全氯含量；连续利用废水灌溉３、５年的粮地土壤未发生Ｎａ＾＋、Ｃｌ＾－和ＳＯ４＾２－的累积，唯耕层土壤有Ｃａ＾２＋、Ｍｇ＾２＋轻度淋失。     

再生水灌溉对土壤性能和土壤微生物的影响研究

土壤性能和土壤微生物是再生水灌溉对环境安全效应评价的重要指标。通过模拟试验,以北京高碑店污水处理厂生产的再生水浇灌大豆为例,分析了收获期土壤理化特性及微生物类群变化。结果表明,再生水灌溉能够在一定程度上提高土壤肥力,表现为有机质和有效磷显著增加;土壤重金属铅、镉含量相对清水和土壤本底无明显增加,但土壤溶液电导值（EC）增加显著,在一定程度上造成盐度累积。在土壤微生物方面,再生水灌溉使土壤细菌数量相对清水灌溉处理增加;二级再生水和三级再生水灌溉处理间的放线菌数量差异显著,且明显高于清水对照;再生水灌溉对真菌数量影响不大。再生水灌溉使大豆根际土壤脲酶活性增加,碱性磷酸酶活性最高。土壤微生物数量、酶活性与土壤养分含量之间呈显著相关关系,可作为评价土壤肥力和土壤环境质量的指标。     

Enhancing the productivity of high‐magnesium soil and water resources in Central Asia through the application of phosphogypsum

Recent evidences from some irrigated areas worldwide, such as Central Asia, suggest that water used for irrigation contains magnesium (Mg²⁺) at levels higher than calcium (Ca²⁺). Excess levels of Mg²⁺ in irrigation water and/or in soil, in combination with sodium (Na⁺) or alone, result in soil degradation because of Mg²⁺ effects on the soil's physical properties. More than 30 per cent of irrigated lands in Southern Kazakhstan having excess levels of Mg²⁺ are characterized by low infiltration rates and hydraulic conductivities. The consequence has been a gradual decline in the yield of cotton (Gossypium hirsutum L.), which is commonly grown in the region. These soils require adequate quantities of Ca²⁺ to mitigate the effects of excess Mg²⁺. As a source of Ca²⁺, phosphogypsum—a byproduct of the phosphorous fertilizer industry—is available in some parts of Central Asia. In participation with the local farming community, we carried out a 4‐year field experiment in Southern Kazakhstan to evaluate the effects of soil application of phosphogypsum—0, 4·5, and 8·0 metric ton per hectare (t ha⁻¹)—on chemical changes in a soil containing excess levels of Mg²⁺, and on cotton yield and economics. The canal water had Mg²⁺ to Ca²⁺ ratio ranging from 1·30 to 1·66 during irrigation period. The application of phosphogypsum increased Ca²⁺ concentration in the soil and triggered the replacement of excess Mg²⁺ from the cation exchange complex. After harvesting the first crop, there was 18 per cent decrease in exchangeable magnesium percentage (EMP) of the surface 0·2 m soil over the pre‐experiment EMP level in the plots where phosphogypsum was applied at 4·5 t ha⁻¹, and a 31 per cent decrease in EMP in plots treated with phosphogypsum at 8 t ha⁻¹. Additional beneficial effect of the amendment was an increase in the soil phosphorus content. The 4‐year average cotton yields were 2·6 t ha⁻¹ with 8 t ha⁻¹ phosphogypsum, 2·4 t ha⁻¹ with 4·5 t ha⁻¹ phosphogypsum, and 1·4 t ha⁻¹ with the control. Since the amendment was applied once at the beginning, exchangeable Mg²⁺ levels tended to increase 4 years after its application, particularly in the treatment with 4·5 t ha⁻¹ phosphogypsum. Thus, there would be a need for phosphogypsum application to such soils after every 4–5 years to optimize the ionic balance and sustain higher levels of cotton production. The economic benefits from the phosphogypsum treatments were almost twice those from the control. Copyright © 2007 John Wiley & Sons, Ltd.     

Soil salinity dynamics in irrigated fields and its effects on paddy‐based rotation systems in southern Kazakhstan

Agricultural production in southern Kazakhstan has experienced significant economic difficulty since the 1980s, accelerating agronomic problems including the salinization of irrigated fields. A thorough understanding of the up‐to‐date situation of soil salinization and its effects on cropping systems is necessary in order to establish sustainable agricultural systems with avoiding land degradation for the region. This study examined the relationships between soil salinity, crop yield and affecting factors including local terrain for two farms. Both farms are characterised by a gentle slope, flat area and localised depressions. Most of the paddy fields showed wash‐out of salts during the irrigation period except in waterlogged fields situated in depressions. Rice yield was adversely affected by the remaining soil salinity, deep ponding water and insufficient drainage capacity in the lower part of the irrigation system. Salt accumulation in the upland fields appeared to increase with cropping years, and was associated with groundwater depth that became shallower at the lower parts of the irrigation systems, adversely affecting the crop growth in most fields. Since the cropping patterns had recently changed in the region, each pattern was compared against the recommendation of this study. Most patterns were concluded to be potentially effective for preventing soil salinization if conducted under an optimum economic and social system. Copyright © 2007 John Wiley & Sons, Ltd.     

Effects of liming on soil magnesium on some soils in New Zealand

Abstract

Results from 2 pastoral field lime trials showed that liming reduced exchangeable Mg. This effect increased with increasing rate of lime and with time following lime application, and was greatest in the top 0–50 mm depth. Soil solutions, sampled 2 years after liming, showed that solution Mg increased in increasing rate of lime. This effect was greatest in the top 20 mm of soil.

Lime incubation studies indicated that Mg fixation did occur on some of the soil studied, at pH >6.2. However, this did not account for the size of the observed effects of liming on exchangeable Mg in the field or explain the observed effects of liming at pH <6.2.

It is suggested therefore, that the major mechanism by which liming reduces exchangeable Mg, on these soils, is through displacement of exchangeable Mg into solution by the added Ca in lime, and subsequent leaching.

Results from other field trials suggest that liming will decrease exchangeable Mg if the change in pH‐dependent CEC (?ECEC) per unit change in soil pH is <15 me 100 g‐¹.     

土地利用方式及土壤特性对土壤调节雨水效率的影响研究

One of the most important functions of soils is to regulate rainwater and mitigate flooding and associated damages; this function can be estimated by the rainwater regulation ratio （η）, i.e., percent of regulated rainwater. Fifteen experimental plots were set up on the hills in Yingtan of Jiangxi Province, southern China. These plots were under three land use patterns, cultivated cropland, noncultivated land, and orchard interplanted with cash crops. With aid of an artificial rainfall simulator and Guelph method, rainfall, runoff, soil infiltration, and so on were measured in situ. Results showed that the orchard interplanted with cash crops was more effective in regulating rainwater than the other two land use patterns. When the maximum infiltration intensity was three times higher than the observed mean,η was higher than 70% for all plots. 77 was related to land use, slope gradient, and soil properties such as soil infiltration, organic carbon, bulk density, and texture. There is still more room to improve capacity of rainwater drainage （underground percolation） than that of rainwater storage in soils. Therefore, enhancing soil permeability is vital to improve the rainwater regulation efficiency in soils.     

Soil organic matter dynamics under grain farming in Northern Kazakhstan

Because of their ability to store a high amount of soil organic matter (SOM), Chernozem soils are one of the most important resources from both agricultural and environmental viewpoints. This study was carried out to determine the SOM budget under grain farming in the Chernozem soil of northern Kazakhstan through the analysis of in situ soil respiration and soil environmental factors such as soil temperature as well as moisture content. Five experimental plots including one fallow field were established at the experimental farm of Barayev Kazakh Research and Production Center of Grain Farming, Shortandy, northern Kazakhstan (mean annual precipitation and average year temperature are 323 mm and 1.6°C, respectively). Mean daily soil temperature increased to above O°C in early April, remaining at above 20°C from mid-June to mid-August, and then sharply decreased to below 5°C at the end of September. Most of the biological activities were considered to be limited from April to September. On the other hand, the soil moisture content remained high after thawing until mid-June and then continuously decreased in the cropped plots except during the rainfall events. The soil respiration rate recorded the highest values from late June to early July and overall fluctuations were similar to those of the soil temperature, unlike the fluctuations of soil microbial C and N contents, which exhibited similar patterns to those of the soil moisture content. In order to represent the daily soil respiration rates using the soil environmental factors, the following relationship was introduced as a model function: Cem = aM ^pbexp(-E/RT). The coefficients, a, b, and E (activation energy in Arrhenius equation), were determined by stepwise multiple regression after logarithm transformation using the measured data, Cem (daily soil respiration rate), M (volumetric soil moisture content), and T (absolute soil temperature). As a result, a significant relationship was always obtained between the soil respiration rate and the activation energy, E, while the contribution of the soil moisture content to the soil respiration rate was uncertain. Using the regression equations and monitored data of soil temperature and moisture content, cumulative soil respiration throughout the cropping period was calculated to be in the range of 2.5 to 3.2 Mg C ha^p-1 On the other hand, the amounts of crop residues in the cropped plots that were expected to be incorporated into the soils ranged from 1.6 to 4.4 Mg C ha^p-1 Except for the plot planted with oats (higher amounts of residues than for wheat), the SOIL budget was slightly negative in this year, that is, the soils lost their organic matter stock. Although it is difficult to generalize the C budget in different years because of the large variations in crop growth due to fluctuating water resources, the disadvantage of summer fallow (no residues) was obvious in terms of SOM budget. The net soil respiration rate in the fallow plot, 2.9 Mg C ha^p-1 was approximately equivalent to 4% of the total SOM stock in the plow layer (30 cm) (70 to 80 Mg C ha^p-1 To reduce further loss of SOM, at least evenly extensive use of summer fallow should be reconsidered.     

渭北旱塬坡耕地水土和养分流失特征

以渭北旱塬的坡耕地为对象,采用定位监测和室内分析相结合的方法,研究其退化机理。取得以下主要结论:坡耕地的土壤退化主要是水土流失所致,水土流失主要集中在年内的几场暴雨。观测期内5°、10°和15°坡面平均产沙量分别为320.9,1 581.1,3 819.6t/(km2.a);平均产流量分别为13 836.4,46 869.3,53 956.5m3/(km2.a)。受降雨强度和坡度影响较大。水土流失导致坡耕地土壤容重增加,孔隙度减小,持水能力减弱,且带走土壤中有效养分量,使土壤肥力降低。流失泥沙中全氮和速效钾含量远高于耕层土壤中的含量,表现出"富集"。     

南亚热带森林演替过程土壤水分、有机质和交换性阳离子的变化格局

Information on the distribution patterns of soil water content （SWC）, soil organic matter （SOM）, and soil exchangeable cations （SEC） is important for managing forest ecosystems in a sustainable manner. This study investigated how SWC, SOM, and SEC were influenced in forests along a successional gradient, including a regional climax （monsoon evergreen broad-leaved forest, or MEBF）, a transitional forest （coniferous and broad-leaved mixed forest, or MF）, and a pioneer forest （coniferous Masson pine （Pinus rnassoniana） forest, or MPF） of the Dinghushan Biosphere Reserve in the subtropical region of southern China. SWC, SOM, and SEC excluding Ca^2＋ were found to increase in the soil during forest succession, being highest in the top soil layer （0 to 15 cm depth） except for Na^＋. The differences between soil layers were largest in MF. This finding also suggested that the nutrients were enriched in the topsoil when they became increasingly scarce in the soil. There were no significant differences （P = 0.05） among SWC, SOM, and SEC. A linear, positive correlation was found between SWC and SOM. The correlation between SOM and cation exchange capacity （CEC） was statistically significant, which agreed with the theory that the most important factor determining SEC is SOM. The ratio of K^＋ to Na^＋ in the topsoil was about a half of that in the plants of each forest. MF had the lowest exchangeable Ca^2＋ concentration among the three forests and Ca^2＋：K^＋ in MPF was two times higher than that in MF. Understanding the changes of SWC, SOM, and CEC during forest succession would be of great help in protecting all three forests in southern China.     

约旦河谷土壤含盐量变化对其灌溉农业可持续发展的潜在危害研究

The integrated effect of irrigation and agricultural practices on soil salinity in the Jordan Valley （JV）, where over 60% of Jordan’s agricultural produce is grown, was investigated in this study during 2009-2010. Due to the differences in agricultural operations, cropping patterns, irrigation management, and weather conditions, 206 top- and sub-soil samples were taken every 1 to 3 km from representative farms along a north-south （N-S） transect with 1 to 2 km lateral extents. Soil electrical conductivity of saturated extract (EC_se), Ca, Mg, K, Na, Cl, and Na adsorption ratio （SAR） were determined in saturated paste extracts. Results indicated that about 63% of soils in the JV are indeed saline, out of which almost 46% are moderately to strongly saline. Along the N-S transect of the JV, EC_se increased from 4.5 to 14.1 dS m^-1 in top-soil samples. Similar increase was observed for the sub-soil samples. The major chemical components of soil salinity; i.e., Ca, Mg, and Cl, also showed a similar increase along the N-S transect of the valley. Moreover, compared to previous field sampling, results showed that changes in soil salinity in the JV were dramatic. In addition, it was found that Cl imposed an existing and potential threat to sensitive crops in 60% of the soils in the JV, where Cl concentrations were greater than 710 mg L^-1. Under the prevalent arid Mediterranean conditions, improving the management of irrigation water, crops, and nutrient inputs and increasing water and fertilizer use efficiencies should be indispensable to conserve and sustain the already fragile agricultural soils in the JV.     

铜仁市植烟土壤交换性钙镁空间分布特征及其影响因素分析

为明确贵州省铜仁市植烟土壤中交换性钙和镁的状况,以铜仁2019年植烟耕层土壤交换性钙镁为研究对象,利用多元统计学和地统计学方法分析了土壤交换性钙镁空间变异特征及其影响因素。结果表明,铜仁植烟土壤交换性钙、镁含量整体丰富,平均值分别为1.72、0.27 g·kg^-1,但仍有19.31%的交换性钙和27.59%地区的交换性镁含量处于低与极低水平。植烟土壤中钙镁比处于适宜范围的比例仅占29.70%,说明钙镁比失调较严重。土壤交换性镁含量总体呈现由西北向东南逐渐增加的趋势,土壤钙镁比总体呈现由中部向东南和西北逐渐减小的趋势,思南中部钙镁比处于最高值,江口南部与松桃南部钙镁比处于最低值。植烟土壤交换性钙、镁含量及其比值的空间变异是由结构性因素和随机性因素共同作用的结果。pH对交换性钙、镁空间变异的影响最大,分别能够独立解释其变量的41.6%、55.7%,且与交换性钙、镁分别呈现幂函数和三次函数关系,随着pH值升高,土壤中交换性钙和镁含量升高。综上,贵州铜仁植烟土壤空间分布不均匀、差异性较大,钙镁比失调比较严重,pH值对交换性钙、镁空间变异的影响最大,并与其呈极显著正相关。因此,铜仁烟区在指导钙镁施肥时要注意其空间差异性、做到分类指导,可以通过调控钙镁肥料施用量或含钙镁的改良剂调节土壤pH值来达到平衡土壤养分的目的。本研究可为铜仁市烟田钙镁养分管理提供科学依据。     

干旱区绿洲灌漠土对铜的吸附解吸特性研究

土壤对重金属的吸附解吸是影响土壤系统中重金属的移动性和归宿的主要过程.本文使用序批实验方法、单步提取方法、连续提取方法等研究了干旱区绿洲灌漠土Cu的吸附解吸特性.结果表明,灌漠土对Cu的吸附等温线可很好地用Freundlich等温方程拟合,灌漠土的Cu吸附可能受土壤理化综合因素影响,而不仅是某个土壤理化指标所控制;二次...