Growth and Yield of Rice(Oryza sativa L.)Applied by Inorganic and Organic Fertilizer in Indonesian Tidal Soil

The aims of this study were to determine the dose of inorganic fertilizer of NPK combined with organic fertilizer from CM(Cow Manure)to grow paddy Inpara 8 variety planted in a tidal soil.This experiment was done in a green house and conducted from July to December 2020.This pot experiment used factorial completely randomized design with two factors and three replications.The first factor was NPK which consisted of two kinds of NPK fertilizers which were urea 200 kg/ha,SP-36100 kg/ha,KCl 100 kg/ha from recommended fertilization and urea 37 kg/ha,SP-3656 kg/ha,KCl 183 kg/ha from calculation of the specific location soil analysis(in situ data).The second factor was dosage of CM at 5,7.5 and 10 tons/ha respectively.The results showed that NPK fertilization from specific location combined with CM at 10 tons/ha was the best treatment for rice production in an infertile tidal swampland producing 2.20 tons/ha.

The Effects of Farmyard Manure and Mulch on Soil Physical Properties in a Reclaimed Coastal Tidal Flat Salt-Affected Soil

Careful soil management is important for the soil quality and productivity improvement of the reclaimed coastal tidal flat saline land in northern Jiangsu Province, China. Farmyard manure（ FYM） and mulch applications, which affect soil characteristics and plant significantly, are regard as an effective pattern of saline land improvement. As a conventional management in the study region, FYM and mulch are used for the amendment of the new reclaimed tidal flat regularly, but little is known about their effects on soil physical properties functioning. A study was conducted on a typical coastal tidal flat saline land, which was reclaimed in 2005, to evaluate the effects of FYM, polyethylene film mulch（PM）, straw mulch（SM）, FYM combined with PM（FYM＋PM）, FYM combined with SM（FYM＋SM）, on soil hydraulic properties and soil mechanical impedance. CK represented conventional cultivation in study area without FYM and mulch application and served as a control. The experiment, laid out in a randomized complete block design with three replications, was studied in Huanghaiyuan Farm, which specialized in the agricultural utilization for coastal tidal flat. Result showed that capillary water holding capacity（CHC）, saturated water content（SWC）, saturated hydraulic conductivity（ Ks） and bulk density（BD）, cone index（CI） were affected significantly by the FYM and mulch application, especially in the 0-10 cm soil layer. FYM and mulch management increased CHC, SWC and Ks over all soil depth in the order of FYM＋SM〉FYM＋PM〉FYM〉SM〉PM〉CK. With the contrary sequence, BD and CI decreased significantly; however, FYM and mulch application affected BD and CI only in the upper soil layers. CHC, SWC and Ks decreased significantly with the increasing of soil depth, BD and CI, and a significant liner equation was found between CHC, SWC, Ks and BD, CI. With the highest CHC（38.15%）, SWC（39.55%）, Ks（6.00 mm h-1） and the lowest BD（1.26 g cm-3） and CI（2.71 MPa）, the combined management of FYM and SM was recommend to be an effective method for the melioration of reclaimed coastal tidal flat saline soil.

Temporal Variations on Soil Salinity and Cation Displacement at Saemangeum and Yeongsangang Reclaimed Tidal Lands

Soil salinity at reclaimed tidal land in Korea is highly variable and depending on soil characteristics and weather conditions. The objective of this study was to evaluate the temporal changes on soil salinity and the relationships between soil salinity and salinity parameters in reclaimed tidal lands. Soil samples were periodically collected at 0 - 20 cm (surface) and 20 - 40 cm (subsurface) layer at Saemangeum (sandy loam) and Yeongsangang (silty loam) reclaimed tidal land. Electrical conductivity (EC) had a wide range from 0.0 to 34.3 dS·m-1 during the experimental period. The average soil EC was 6.4 and 3.4 dS·m-1 at Saemangeum and Yeongsangang reclaimed tidal land, respectively. Soluble sodium concentration had great variations and it was the most important single factor for temporal variations of soil EC regardless of soil textural properties. Calcium concentration was negatively correlated with soil EC and soluble sodium. Soil exchangeable sodium percentage (ESP) was estimated as a function of soil sodium adsorption ratio (SAR) and a linear regression model (ESP = 6.075 (SAR) + 0.677 for Saemangeum and ESP = 3.925 (SAR) + 0.421 for Yeongsangang reclaimed tidal soil) was suggested for predicting soil ESP from soil SAR. The characteristics of reclaimed tidal lands had different shares of saline and sodic properties during the experimental period. Saemangeum reclaimed tidal soil was highly characterized by sodium, but the effect of sodium on Yeongsangang soil was less pronounced. Our results indicate that persistent monitoring and modeling on soil salinity at reclaimed tidal soil is fundamental and the results can provide some useful information for deciding management plans for diverse utilization or to reduce salt damage for stable crop production at reclaimed tidal land.

Assessment of Soil Quality of Tidal Marshes in Shanghai City

We take three types of tidal marshes in Shanghai City as the study object:tidal marshes in mainland,tidal marshes in the rim of islands,and shoal in Yangtze estuary.On the basis of assessing nutrient quality and environmental quality,respectively,we use soil quality index(SQI)to assess the soil quality of tidal flats,meanwhile formulate the quality grading standards,and analyze the current situation and characteristics of it.The results show that except the north of Hangzhou Bay,Nanhui and Jiuduansha with low soil nutrient quality,there are not obvious differences in soil nutrient quality between other regions;the heavy metal pollution of tidal marshes in mainland is more serious than that of tidal marshes in the rim of islands;in terms of the comprehensive soil quality index,the regions are sequenced as follows:Jiuduansha wetland>Chongming Dongtan wetland>Nanhui tidal flat>tidal flat on the periphery of Chongming Island>tidal flat on the periphery of Hengsha Island>Pudong tidal flat>Baoshan tidal flat>tidal flat on the periphery of Changxing Island>tidal flat in the north of Hangzhou Bay.Among them,Jiuduansha wetland and Chongming Dongtan wetland have the best soil quality,belonging to class III,followed by Nanhui tidal flat,tidal flat on the periphery of Chongming Island and tidal flat on the periphery of Hengsha Island,belonging to class IV;tidal flat on the periphery of Changxing Island,Pudong tidal flat,Baoshan tidal flat and tidal flat in the north of Hangzhou Bay belong to class V.

不同含水率与静置时间下滩涂土壤流变特性试验

为了研究贝类养殖的滩涂土壤的流变属性和结构稳定性,采用旋转流变仪对不同含水率和不同静置时间的滩涂土壤进行了流变试验,通过单因素试验研究了各因素对滩涂土壤流变特性的影响,并分析了土壤剪切过程中的变化机理。同时,通过Response Surface Methodology中的Central Composite Design试验建立了屈服应力与含水率和静置时间之间的数值模型,并比较了含水率和静置时间对屈服应力产生的影响。结果表明:1)剪切过程中滩涂试样经过了弹塑性阶段、固液转化阶段和流体阶段,滩涂土壤表现出了静置时间越长,固液转化阶段就越长的性质,且剪切过程中表现出剪切稀化的性质。2)静置时间的增加会导致整体剪切应力和屈服应力同时增加,含水率的增加会导致整体剪切应力和屈服应力的降低,且滩涂土壤存在一个含水率分界点,此含水率分界点在64.5%~67.0%之间,当超过这个含水率分界点的试样的静置时间超过31 h时,试样的屈服应力基本不会再发生较大的波动,大小在2240~4380 Pa之间,此外,静置时间在0~53 h之间且含水率在62.0%~69.5%之间的试样的屈服应力在1870~5410 Pa之间。3)含水率对屈服应力的影响比静置时间的影响更加显著,模型的R^(2)为0.9534,并且在验证试验中,屈服应力的测量值与预测值之间的误差在15.0%以内,都说明了数值模型的可靠性。研究定性和定量地表征了滩涂土壤的流变特性,为滩涂贝类采收机械的研发和优化提供参考。

江苏沿海滩涂垦区不同播种量对小麦产量的影响及小麦生长季土壤因子变化动态

利用供试品种小麦扬麦16在江苏南通沿海滩涂围垦区开展3个播种量水平处理的小麦种植试验,旨在研究不同播种量水平对沿海滩涂小麦产量及其构成因素的影响,明确滩涂小麦生长期间土壤盐分、pH值、土壤水分和土壤温度的变化动态。结果表明:1)沿海滩涂小麦种植过程中,0~20 cm和20~40 cm土壤盐分(电导率)变化幅度分别为0.258~0.478 dS/m和0.258~0.496 dS/m,且各处理土壤盐分表现为12月至翌年3月底处于稳定期,4月上旬开始出现土壤返盐状态;2)不同播种量处理下土壤pH值和土壤水分均具有一致的季节性变化特征,且各处理下0~20 cm和20~40 cm土壤pH值变化幅度分别在7.80~8.55、8.52~9.37,各处理下0~20 cm和20~40 cm土壤水分变化幅度分别在19.35%~24.13%、21.51%~23.66%;3)不同播种量水平处理下各土层温度(0、5、10、15 cm)与大气温度变化均表现出相似的季节性变化规律,且各土层温度与大气温度之间均具有极显著的正相关关系(P<0.01);4)沿海滩涂种植小麦过程中,D2(225.0 kg/hm^(2))和D3(262.5 kg/hm^(2))处理相比D1(187.5 kg/hm^(2))处理小麦产量分别显著提高了5.74%、5.06%(P<0.05),穗数显著提高了9.68%、10.54%(P<0.05),且D2和D3处理之间滩涂小麦产量和穗数差异均无统计学意义;同时,D1、D2和D3处理下滩涂小麦的穗粒数和千粒质量差异均无统计学意义。因此,本试验条件下,滩涂小麦种植过程中不同播种量水平没有明显改变土壤盐分等指标的变化动态,滩涂小麦产量的提高主要是因穗数增加引起的。综合考虑经济效益,播种量225.0 kg/hm^(2)是滩涂小麦比较适宜的播种量水平。

Lead Accumulation in Tidal Swamps:Case Study at Transmigration Area of South Sumatra Indonesia after 40 Years Cultivation

Lead(Pb)is a heavy metal that poses a major hazard to animals and humans when consumed.The content of this metal is significantly high in paddy soil due to the residual effect of phosphate fertilizer.Therefore,this study aims to determine the Pb content in the tidal swamp that has been used for agriculture for 40 years.It was carried out from October 2021 to January 2022 on tidal soils representing land typology of A,B,C,and D distributed in the Transmigration area of Mulia Sari,Tanjung Lago District,Banyuasin Regency of South Sumatra,Indonesia.A detailed survey was used and soil samples were taken from up to 12 soil sampling points.The variables observed were soil Pb,pH,CEC(Cation Exchange Capacity),pyrite,and C-organic.The results showed that the Pb content in tidal soils obtained was varied,namely 22.52 mg/kg,14.84 mg/kg,16.84 mg/kg,and 16.68 mg/kg for A,B,C,and D type of land typologies,respectively.Based on these values,the Pb accumulation has exceeded the threshold,which is 12.75 mg/kg.

Fertilization Affects Biomass Production of Suaeda salsa and Soil Organic Carbon Pool in East Coastal Region of China

Land use practice significantly affects soil properties. Soil is a major sink for atmospheric carbon, and soil organic carbon （SOC） is considered as an essential indicator of soil quality. The objective of this study was to assess the effects of N and P applied to Suaeda salsa on biomass production, SOC concentration, labile organic carbon （LOC） concentration, SOC pool and carbon management index （CMI） as well as the effect of the land use practice on soil quality of coastal tidal lands in east coastal region of China. The study provided relevant references for coastal exploitation, tidal land management and related study in other countries and regions. The field experiment was laid out in a randomized complete block design, consisting of four N-fertilization rates （0 （NO）, 60 （N1）, 120 （N2） and 180 kg ha-1 （N3））, three P-fertilization rates （0 （P0）, 70 （P1） and 105 kg ha-~ （P2）） and bare land without vegetation. N and P applied to S. salsa on coastal tidal lands significantly affected biomass production （above-ground biomass and roots）, bulk density （Pb）, available N and P, SOC, LOC, SOC pool and CMI. Using statistical analysis, significantly interactions in N and P were observed for biomass production and the dominant factor for S. salsa production was N in continuous 2-yr experiments. There were no significant interactions between N and P for SOC concentration, LOC concentration and SOC pool. However, significant interaction was obtained for CMI at the 0-20 cm depth and N played a dominant role in the variation of CMI. There were significant improvements for soil measured attributes and parameters, which suggested that increasing the rates of N and P significantly decreased Pb at the 0-20 cm depth and increased available N and P, SOC, LOC, SOC pool as well as CMI at both the 0-20 and 20-40 cm depth, respectively. By correlation analysis, there were significantly positive correlations between biomass （above- ground biomass and roots） and SOC as well as LOC in 2010 and 2011 across all soil depth, respectively. The treatment with N at 180 kg ha-~ and P at 105 kg ha-1 was superior to the other treatments. The results from the 2-yr continuous experiments indicated that, in short-term, there were a few accumulation of SOC and LOC concentrations by means of N and P application to S. salsa, whereas in the long run, S. salsa with N and P application was recommended for coastal tidal lands because of its great potential of carbon sequestration, improvements of soil nutrition status and promotion of soil quality.

浅覆土盾构穿越潮汐河流地层变形规律

当前中国城市轨道交通发展迅速,地铁开挖下穿越潮汐河流面临诸多风险。为研究浅覆土盾构穿越潮汐河流的地层变形规律,以青岛地铁四号线盾构法穿越某浅覆土潮汐河流为依托,重点考虑河流的潮汐变化,结合工程中采用的注浆压力、工作面压力等施工参数,运用数值模拟的手段建立了更加符合实际情况的起伏地层,进而对地层变形规律开展研究。研究发现河底地层变形与河道水位深度呈正相关;涨潮和退潮时的地层横向沉降曲线形状存在差异且最大沉降量相差达50%;隧道掘进在时间效应上的地表沉降可分为4个阶段,需加强对中期盾构开挖及加固阶段的监测频率。

化学农药对三沙湾滩涂土壤细菌多样性及其功能的影响

为探究除草剂草甘膦和杀虫剂毒死蜱对三沙湾滩涂土壤细菌群落结构及多样性的影响,利用五点采样法于2021年3月采集福建省霞浦县东吾洋沿岸滩涂土壤,通过模拟自然环境在室内进行农药添加试验,两种农药分别设置3个浓度,即草甘膦5、25、125 mg·kg^(-1),毒死蜱6、30、150 mg·kg^(-1),染毒时间分别取3 d和10 d,以未添加农药的滩涂土壤为对照。使用Illumina MiSeq PE300二代高通量测序平台对各处理及对照滩涂土壤细菌16S rRNA基因的V3~V4区进行测序,分析不同处理土壤细菌群落组成结构和功能差异及其影响因素。结果表明:草甘膦和毒死蜱显著降低了三沙湾滩涂土壤细菌α多样性(P<0.05)。门水平上,滩涂土壤中优势菌群包括变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、绿弯菌门(Chloroflexi)和ε-变形菌门(Epsilonbacteraeota),其丰度占比分别为32.69%、20.38%、12.46%和9.14%,农药处理后其优势菌群主要由变形菌门、厚壁菌门和拟杆菌门(Bacteroidetes)组成。属水平上,对照土壤以深海芽孢杆菌属(Thalassobacillus)、海杆菌属(Marinobacter)、硫卵菌属(Sulfurovum)和芽孢杆菌属(Bacillus)为主,农药处理后其优势菌群海杆菌属和芽孢杆菌属得到大量扩增,其他菌属呈现不同程度的衰退。Tax4Fun功能分析结果显示,各处理滩涂土壤的功能类群主要集中在新陈代谢方面,不同阶段细菌功能主要分布于38类代谢通路。经农药处理,滩涂土壤中氨基酸代谢、异生素降解和代谢、脂类代谢、萜类化合物和聚酮的代谢以及环境信息处理中膜运输、细胞运动和细胞运输同化作用等功能得到明显增强,而能量代谢、聚糖生物合成和代谢、遗传信息处理等功能有不同程度的削弱。由此可见,化学农药的加入降低了三沙湾滩涂土壤细菌群落多样性,微生物多样性的损失将改变生态系统的功能,降低生态系统的稳定性。

基于原位光谱的滨海滩涂土壤含水量预测模型

【目的】滩涂土壤含水量对滨海区域生态保护和植物生长都至关重要,及时了解土壤含水量对生态恢复、土壤资源管理和土壤可持续利用具有重要意义。针对土壤含水量获取复杂的问题,探求更加快速精准地获取滨海滩涂土壤含水量的方法。【方法】沿沧州滨海区域采集了共计14个表层(0~20 cm)滩涂土壤样品,在实验室利用烘干法测得滩涂土壤含水量。在分析野外实测滨海滩涂土壤原位高光谱反射率(R)和土壤含水量特性的基础上,采用反射率倒数(1/R)、反射率倒数对数(log(1/R))、反射率一阶微分(R')和反射率去包络线(CR)等变换形式。充分挖掘光谱信息,并探求与滨海滩涂土壤高相关性的可见近红外(VIS-NIR)光谱波段,构建基于多元逐步线性回归(MSR)和支持向量机回归(SVR)方法的滨海滩涂土壤含水量预测模型。结合适用于小样本的留一交叉验证(LOO-CV)法验证模型精度,并对比分析两种预测模型的性能以及模型的稳定性。【结果】研究发现:1)土壤光谱反射率与对应土壤含水量呈显著负相关,且二者在1400~1600 nm和1900~2400 nm内密切相关。2)除R外,同一种光谱变换形式下,采用SVR方法构建的滨海滩涂土壤含水量预测模型精度和稳定性明显高于MSR方法,对比得出基于R´的滨海滩涂土壤含水量SVR预测模型精度最高,Adjusted-R2、RPD和RMSE分别为0.81、2.08和2.56。【结论】在R'变换形式下利用SVR方法建立的模型能够较准确地预测滨海滩涂土壤含水量,为滨海湿地土壤管理、植物生长和环境保护提供必要的数据支持,并为基于高光谱影像的区域尺度土壤含水量预测提供方法借鉴。

设施西瓜土壤养分投入与累积及环境风险分析

为明确河北省设施西瓜主产区养分投入、累积与氮素淋失风险,选取81个设施西瓜大棚与27个对照农田,进行实地调研与土壤样品采集,评价土壤养分丰缺状况与累积量,预测硝态氮淋失风险。结果表明:设施西瓜田有机肥和化肥平均用量分别为47550和1301.48 kg/hm^(2),是农田的1.10倍和1.27倍,土壤中氮、磷、钾养分表观盈余量分别是携出量的5.00、7.21和2.96倍。0~20 cm土层中,硝态氮、有效磷、速效钾和有机质处于丰富水平,分别占比70.37%、33.33%、100%和40.74%,且各养分含量随着土层加深而逐渐降低。设施西瓜田0~60 cm土层硝态氮、有效磷和速效钾的平均累积量分别是农田土壤的1.43、1.53和1.69倍。并且设施西瓜田土壤硝态氮向下层迁移明显,分别在60~80 cm和120~140 cm出现累积峰;模型预测在150~400 cm土层有均有较高累积量,是农田的8.33~9.55倍。因此,河北省设施西瓜田养分投入量过高,易造成土壤养分的高累积与硝态氮向深层淋失,对地下水存在氮污染的风险。

潮汐作用下爆破挤淤法路基内力变化分析

爆破挤淤法作为一种经济高效的软土地基处理方法,被广泛应用于滨海潮间带淤泥质软土地基处理,然而位于潮间带区域的路基常年经受潮汐作用,涨落潮的变化可能导致土体内部结构和力学性质发生变化,从而影响路基运营的安全性和稳定性。为了探明潮汐作用下潮间带爆破挤淤法处理路基内力演化的规律,研究依托福建宁德某潮间带爆破挤淤法地基处理项目,利用光纤光栅传感器对其进行土压力和渗压力监测。通过对比分析监测数据,可知传感器所采集到的数据能够揭示土压力和渗压力的变化规律,表明路基土压力和渗压力会随着潮水位涨落发生变化,并且二者具有相似的变化曲线,涨落潮对爆破挤淤法处理路基稳定性存在潜在的影响。

4种生物炭对镉污染潮土钝化修复效果研究

以甘蔗叶、木薯秆、水稻秸秆和蚕沙为原材料,采用限氧热解法在500℃下制备生物炭,通过室内培养实验,研究在不同培养时间(0,15,30,45d)条件下,生物炭施入潮土(Cd浓度5mg/kg)后对土壤基本性质及土壤中镉(Cd)化学形态的影响,探讨了生物炭修复镉污染土壤的可行性。结果表明:添加生物炭后,土壤pH值和阳离子交换量(CEC)随着培养时间的增加而逐渐增加,而土壤有机碳(SOC)含量则呈先增加至最大值而后缓慢降低的趋势,但仍高于对照。同时,生物炭的施入显著降低了土壤中弱酸可提取态Cd和可还原态Cd含量,提高了可氧化态Cd和残渣态Cd含量,且随着培养时间的延长这种转化趋势更为明显。4种生物炭对潮土中Cd钝化效果表现为蚕沙生物炭>水稻秸秆生物炭>木薯秆生物炭>甘蔗叶生物炭。培养结束(45d)时,与对照相比,添加蚕沙生物炭的土壤中弱酸可提取态Cd含量降低了42.07%,可还原态Cd含量降低了35.19%,可氧化态Cd和残渣态Cd含量分别增加了292.59%和339.29%,从而大大降低了Cd的生物有效性,由此可见,生物炭对镉污染土壤的修复是切实可行的。

珠江口滩涂湿地土壤重金属分布及其对围垦的影响

通过系统取样和原子分光光度法测试,对珠江口滩涂湿地土壤重金属分布及其对围垦的影响进行了研究。结果显示,珠江口滩涂湿地土壤127个表层样品中Zn、Cr、Cu、Ni、Pb、Cd的平均含量分别为305.4、80.3、70.2、69.4、35.1、3.98mg·kg^(-1),其空间分布主要受排污口、围垦、潮滩位置和土壤粘土含量控制。滩涂湿地土壤受Cd、Zn、Ni污染十分严重,对围垦带来了严重的生态风险。

不同施肥方式下滩涂围垦农田土壤有机碳及团聚体有机碳的分布

通过在苏北滩涂地区开展田间试验，研究了不同施肥处理（不施肥、施农家肥、商品有机肥、无机肥）对滩涂地区围垦农田土壤有机碳及团聚体有机碳的影响。结果表明，与对照相比，不同施肥处理均能明显增加0～30cm土层土壤有机碳含量和有机碳密度，施农家肥增加幅度最高，增加值分别为0．66g kg^-1和0．07kg m^-2。试验地区水稳性团聚体以〉5mm和0．25～0．5mm为主，含量分别为37％～57％和13％～20％；随着土层深度增加，〉5mm团聚体含量降低，0．25～0．5mm团聚体则增加；农家肥能显著增加〉5mm团聚体含量，同时降低0．25～5mm团聚体含量。团聚体中有机碳含量表现为，除0．25～0．5mm团聚体外，〉5mm至0．5～1mm团聚体之间，粒径越小，有机碳含量越高，其中0．5～1mm团聚体有机碳含量最高，为6．83g kg^-1；与其他处理相比，农家肥的施用能明显增加各粒级团聚体中有机碳含量。试验地区土壤有机碳含量与〉5mm团聚体及其有机碳含量极显著正相关（p〈0．01），而与0．25～5mm团聚体负相关（p〈0．01或p〉0．05）。

珠三角滩涂围垦农田土壤和农作物重金属污染

为了研究珠三角滩涂围垦农田土壤和农作物重金属污染状况,采集了广州南沙、中山一带围垦农田农作物及其根际土壤样品,测定重金属的质量分数。结果表明,围垦农田土壤样品中Cu、Pb、Cd、Ni、Cr和Zn含量均大于广东省相应土壤环境背景值,其中Cu(56.06mg·kg-1)、Pb(48.30mg·kg-1)、Cd(0.72mg·kg-1)、N(i41.15mg·kg-1)、C(r115.1mg·kg-1)和Zn(200.1mg·kg-1)分别为背景值的3.30、1.34、12.82、2.26、2.28和4.23倍。与《土壤环境质量标准》(GB15618—1995)中Ⅱ级标准(pH<6.5)比较,土壤样品中Cu、Cd、Ni和Zn的超标率分别为73.7%、88.6%、59.6%和28.9%。以GB15618—1995中Ⅱ级标准为评价标准,采用Nemerow指数法进行评价,土壤重金属平均综合污染指数为1.86,属3级轻污染。与《食品中污染物限量》(GB2762—2005)等相关标准比较,农作物中Cu、Pb、Cd、Ni、Cr和Zn含量的样品超标率分别为0、28.9%、2.6%、48.3%、12.3%和6.1%。由此可见,珠三角滩涂围垦农田土壤和农作物重金属污染问题已经比较突出,土壤污染以Cd为主,而农作物污染则以Ni、Pb、Cr为主。

施用生活污泥改良滩涂土壤理化性状的探讨

采用符合土地改良用标准的生活污泥为材料,通过田间小区随机区组试验,研究生活污泥的不同施用量(0、75、150、300、600 t/hm2)对滩涂土壤部分理化性质的影响。结果表明,施用生活污泥可显著改善滩涂土壤的理化性状。随着污泥施用量的提高,滩涂土壤的容重、密度、pH值逐渐下降,有机质、全氮、全磷、速效氮、速效磷、CEC均呈上升趋势,全钾、速效钾无显著变化。滩涂土壤的细菌、放线菌数量随污泥施用量的提高呈上升趋势。

有机肥与覆盖方式对滩涂围垦农田水盐与作物产量的影响

针对土壤盐碱障碍因子普遍存在于新围垦滩涂农田并严重抑制作物生长的问题,设置了有机肥(鸡粪堆肥)、薄膜覆盖、秸秆覆盖及有机肥+薄膜覆盖、有机肥+秸秆覆盖组合措施,研究其对土壤水盐的调控作用与对作物生长的促进效应。结果表明:各调控均有利于滩涂围垦农田土壤水盐环境的改善、作物的生长,并整体表现出组合措施优于单项措施、秸秆覆盖优于薄膜覆盖的趋势。其中,有机肥+秸秆覆盖组合措施为调控措施中的优化处理,表现在土壤含水量高、土壤电导率与pH值低,作物产量高,增产率达100%以上。单施有机肥虽能增加土壤含水量、降低土壤pH值,但其土壤电导率升高了11.56%,产生了一定的次生盐渍化风险,与覆盖措施的组合能有效控制土壤盐分的表聚,使其显著低于对照,从而保证了有机肥的持续使用。该研究表明,有机肥与覆盖传统农艺措施的有效组合可较好地调控滩涂围垦农田土壤水盐,促进作物增产,该研究为苏北滩涂新垦农田盐碱障碍因子的消减及作物增产提供了一种新途径,也为当地有机肥及秸秆资源的可持续利用提供了依据。

滩涂围垦区土壤重金属调查及生态风险评价——以盐城市弶港镇为例

以苏北盐城弶港镇滩涂围垦土壤为研究对象,进行了重金属Cr、Pb、As、Cd、Hg的测定及其风险评价,为我国沿海滩涂种植业的发展提供依据,并为其他国家和地区相关研究提供参考。结果表明,该区域土壤中5种重金属含量均未超过《国家土壤环境质量标准》(GB15618—1995)一级标准限制,农田土壤Cr、As、Cd含量较高,郊区菜地土壤Pb、Hg含量较高;重金属Cr、Pb、As、Cd含量在不同土地利用类型间存在显著性差异;Hg含量差异不显著。采用地积累指数法进行评估可知,土壤没有受到单项重金属污染。依据内梅罗综合指数法评估可知,潮间带沉积物、工业区土壤、滩涂围垦熟化的土壤没有受到重金属污染;郊区菜地与农田土壤的污染等级已达到警戒线,污染水平属于"尚清洁"。Hakanson潜在生态风险评价结果表明,区域内土壤重金属处于无风险等级,尚不具有潜在生态风险。