不同通风方式对污泥堆肥的影响

采用2种通风方式和5种调理剂进行污泥堆肥,堆温均能顺利达到设定温度(60℃),并能保持一段高温期,堆肥产品的卫生学指标达到了无害化国家标准.同采用正压强制通风相比,采用自然通风与正压强制通风相结合方式,堆温上升迅速,能耗更低.但正压强制通风能加快堆料含水率的降低和有机质的降解.堆料含水率能极大地影响污泥堆肥过程,堆料的含水率不宜超过80%,在污泥堆肥过程中不必对堆料的pH值进行调整.     

Soil amendments and cultivar selection can improve rice yield in salt-influenced (tsunami-affected) paddy fields in Sri Lanka

The tsunami disaster in the Indian Ocean in December 2004 caused devastation of agricultural soils by salt water over wide areas. Many rice fields located close to the coast were affected by the flood of seawater. Electric conductivity (EC) of soils in tsunami-affected rice fields was found to be higher compared to unaffected fields 2 years after the tsunami. Four soil amendments (gypsum, dolomite, cinnamon ash and rice-husk-charcoal) were tested for their influence on improving the yield parameters of rice grown in a tsunami-affected and a non-affected area. Yield parameters were compared with an untreated control of the same cultivar (AT362) and with a salt resistant rice variety (AT354). The salt resistant variety had the highest grain yield. The two amendments gypsum and rice-husk-charcoal led to an increase in grain yield compared to the untreated control, whereas dolomite and cinnamon ash had no significant effect on grain yield.     

添加剂对伴矿景天修复石灰性铅冶炼污染土壤的影响

为了探讨利用伴矿景天(Sedum plumbizincicola)修复北方重金属污染土壤的可行性,在河南省某铅冶炼形成的污染农田(全镉、铅和锌含量分别为2.65、261和130 mg·kg-1)上种植种子苗或扦插苗伴矿景天,并设对照(CK)、单独尿素(U)、尿素和单质硫(U+S)、尿素与鸡粪(U+CM)配合处理,生长7个月后采样分析.结果表明,种子苗产量比扦插苗高45.8%~162.0%,U、U+CM处理产量均明显高于CK,而U+S处理产量有所下降.种子苗地上部镉含量比扦插苗高15%~99%(p0.05),多数处理铅和锌含量也是种子苗高于扦插苗.与CK相比,各处理措施均导致伴矿景天地上部镉和铅含量下降,而U+S、U+CM处理均导致伴矿景天地上部锌含量上升.从伴矿景天地上部重金属积累量判断,与CK相比,对于镉,仅种子苗U+CM处理镉积累量有所上升;U处理种子苗和扦插苗地上部锌积累量分别比CK上升43.5%和32.3%,两种苗U+S处理锌积累量比CK分别上升11.1%和22.3%.种子苗和扦插苗地上部镉的积累量分别为137~178 g·hm-2和43.7~64.8 g·hm-2,锌的积累量分别为297~1042 g·hm-2和162~326 g·hm-2,两类苗对铅的积累量小于28.8 g·hm-2.U+CM处理对伴矿景天地上部锌吸收的促进作用主要是由于鸡粪中含有大量的有效锌.以上结果表明,可利用种子苗伴矿景天结合尿素的施用对铅冶炼污染石灰性土壤进行修复.     

Influence of cow-dung amendment on glyphosate mobility in soil

Abstract

Sorption and desorption characteristics of glyphosate on native soil and soil amended with cow dung were investigated. Sorption was pH dependent and decreased with increasing pH. Glyphosate partition coefficient ranged from 275 to 16,200?L kg^?1 in native soil, but for soil amended with cow dung it was significantly lower, viz 180–1530?L kg^?1. Glyphosate partition coefficient showed strong negative correlation with cation exchange capacity and positive correlation with surface area. Phosphate in cow dung suppressed glyphosate sorption and enhanced desorption. This study revealed that cow-dung addition to soil could raise the mobility of glyphosate towards groundwater contamination due to the presence of phosphate.     

Wood pellet fly ash and bottom ash as an effective liming agent and nutrient source for rye grass (Lolium perenne L.) and oats (Avena sativa)

Fly ash (FA) and bottom ash (BA) from a softwood pellet boiler were characterized and evaluated as soil amendments. In a greenhouse study, two plant species (rye grass, Lolium perenne L. and oats, Avena sativa) were grown in three different treatments (1% FA, 1% BA, non-amended control) of a silty loam soil. Total concentrations of plant nutrients Ca, K, Mg, P and Zn in both ashes were elevated compared to conventional wood ash. Concentrations of Cd, Cr, Pb, Se and Zn were found to be elevated in the FA relative to BA and the non-amended soil. At 28 d, oat above-ground biomass was found to be significantly greater in soil amended with FA. Potassium and Mo plant tissue concentrations were significantly increased by addition of either ash, and FA significantly increased Zn tissue concentrations. Cadmium and Hg tissue concentrations were elevated in some cases. As soil amendments, either pellet ash is an effective liming agent and nutrient source, but high concentrations of Cd and Zn in FA may preclude its use as an agricultural soil amendment in some jurisdictions. Lower ash application rates than those used in this study (i.e. <1%) may still provide sufficient nutrients and effective neutralization of soil acidity.     

组配改良剂对污染稻田中Pb、Cd、Cu和Zn钝化效果持续性比较

为研究组配改良剂碳酸钙+海泡石(LS)对稻田土壤重金属Pb、Cd、Cu、Zn钝化效果的持久性,通过一次性施用0、2、4、8 g·kg-1的LS,并分别于2012年(第一季)、2013年(第二季)和2014年(第三季)连续种植水稻,在湘南某矿区附近污染稻田进行了一个3 a的大田修复试验.结果表明:1LS能显著提高三季土壤p H值,且LS对土壤p H值提高效果为:第一季第二季第三季.2LS能显著降低三季水稻土壤中Pb、Cd、Zn的交换态含量,且第三季水稻土壤中Pb、Cd、Zn的交换态含量分别降低32.6%~97.7%、8.3%~71.4%和10.9%~83.5%,但对降低三季土壤中Cu的交换态含量无显著影响;LS降低三季土壤中Pb、Cd、Cu、Zn交换态含量的效果均为:PbZnCdCu.3LS使第三季水稻糙米中Pb和Cd含量分别降低26.7%~66.7%、59.1%~80.3%,这种降低效果均随着改良剂LS添加量的增加而增大,但对糙米中Cu和Zn含量无明显影响.LS降低糙米中Pb、Cd、Cu、Zn含量的效果为:第一季,PbCdCuZn;第二季,PbCdCuZn;第三季,CdPbZnCu.LS降低三季水稻糙米中重金属含量的整体效果为PbCdCuZn.4随着时间的延长,LS对土壤中Pb和Cd具有更稳定的钝化效果.因此,LS对治理Pb和Cd污染的土壤具有良好的持久性.     

三元土壤调理剂对田间水稻镉砷累积转运的影响

通过镉砷复合污染稻田的土壤调理剂原位治理,研究了三元土壤调理剂QFJ（羟基磷灰石+沸石+改性秸秆炭）对稻田土壤基本理化性质和水稻各部位镉砷累积转运的影响.结果表明,在土壤Cd总量3.58 mg·kg^-1,As总量124.79 mg·kg^-1污染程度下,施用QFJ后,水稻根际土壤pH值、阳离子交换量及有机质含量有增大的趋势;土壤交换态Cd和As含量可分别从0.37 mg·kg^-1、0.07 mg·kg^-1下降到0.12 mg·kg^-1、0.04 mg·kg^-1.QFJ的施用,可有效降低水稻各部位中Cd和As含量,在9.00 t·hm^-2施用量水平,可将糙米中Cd含量从0.46 mg·kg^-1下降到0.18 mg·kg^-1,无机As含量从0.25 mg·kg^-1降低到0.16 mg·kg^-1,同时低于国家食品污染物限量标准0.2 mg·kg^-1的要求,实现水稻安全生产.施用QFJ减少了水稻根系对Cd和As的富集,降低了水稻植株将Cd从地下部转运到地上部的能力,降低了根系转运Cd的能力以及茎叶、谷壳转运As的能力.     

广东大宝山多金属污染排土场耐性植物与改良剂稳定修复研究

通过在广东大宝山多金属污染排土场种植重金属耐性作物红麻、苎麻,辅以石灰+有机肥、石灰+生物炭的土壤改良,研究不同植物稳定修复模式下植物的生长状况、土壤pH与重金属含量、径流液产生与理化性质的变化情况.结果表明:改良剂处理有效促进红麻、苎麻生长,提高株高、根长和生物量,有助于排土场土壤的植被恢复.石灰与有机肥、生物炭的施加可以改善土壤酸性环境,将土壤pH由酸性显著提高至中性,降低土壤重金属生物有效性,且生物炭的作用更显著;随着红麻、苎麻稳定修复时间的增加,土壤重金属有效态含量呈一定程度下降趋势.植物的定植和土壤改良还可以减少地表径流的产生;提高径流液pH,但pH会随着修复时间的增加而下降;径流液中溶解态和悬浮态重金属含量均在植物稳定修复过程中得到降低,土壤中重金属污染物的扩散迁移得到有效控制.     

组配改良剂对土壤-蔬菜系统铅镉转运调控的场地研究

以组配改良剂LS(石灰石∶海泡石=2∶1)为试验材料,通过对湘南某矿区附近铅镉复合污染旱地土壤进行现场改良钝化,研究施加不同量的LS(0、2、4、8 g·kg-1)对茄子和苋菜植株吸收累积Pb和Cd的影响以及对Pb和Cd在2种蔬菜植株各部位间转运的调控.结果表明:1施加LS能够显著提高土壤p H,降低土壤中交换态Pb和Cd的含量.2施加LS能显著降低2种蔬菜植株各部位中Pb和Cd的含量.LS施加量为2~8 g·kg-1时,茄子果实中Pb和Cd的含量分别降低44.7%~78.6%和36.0%~78.7%;苋菜植株茎叶中Pb和Cd的含量分别降低45.8%~59.1%和40.0%~87.2%.3LS的施加降低了2种蔬菜植株各部位间Pb和Cd的转运系数.2种蔬菜植株在根-茎-果实间或根-茎叶间转运Cd的能力大于Pb,且施加LS各处理下,同种蔬菜相同部位对Pb和Cd的转运能力大小关系保持不变.     

磁性锆铁改性膨润土添加对河道底泥磷迁移与形态转化的影响

首先采用Fe~(3+)、Fe~(2+)、溶解性锆盐、膨润土和碱液作为原料制备得到了一种磁性锆铁改性膨润土,再通过底泥培养实验考察了磁性锆铁改性膨润土添加对底泥中磷迁移与形态转化的影响.结果表明,在缺氧条件下,河道底泥中磷会被释放进入间隙水中,继而会被释放进入上覆水中,而磁性锆铁改性膨润土添加可以极大地降低底泥中磷向间隙水的迁移通量,最终导致了上覆水中磷数量的显著下降.此外,添加磁性锆铁改性膨润土不仅促使底泥中弱吸附态磷(Liable-P)和氧化还原敏感态磷(BD-P)这2种容易释放态磷向较为稳定的金属氧化物结合态磷(NaOH-rP)和非常稳定的残渣态磷(Res-P)转变,而且降低了底泥中水溶性磷(WSP)、易解吸磷(RDP)、NaHCO_3可提取磷(Olsen-P)、藻类可利用磷(AAP)和铁氧化物-滤纸提取磷(FeO-P)这5种不同类型生物有效态磷(BAP)含量,从而降低了底泥中磷的释放风险.从底泥中分离出来的磁性锆铁改性膨润土中潜在活性磷(NH4Cl-P+BD-P)占总磷的26%左右,且含一定数量的FeO-P和Olsen-P(含量分别为161 mg·kg~(-1)和127mg·kg~(-1)).因此,及时采用磁分离的方式从底泥中将吸附磷后的磁性锆铁改性膨润土回收是非常必要的.磁性锆铁改性膨润土添加控制河道底泥中磷释放的机制是:改良剂通过对底泥中潜在活性磷和生物有效态磷的钝化作用,以及通过对间隙水中磷的吸附作用,降低了底泥中磷向间隙水的释放风险,导致间隙水中磷浓度的下降,进而降低了底泥-上覆水界面磷的扩散通量,最终导致上覆水中磷浓度的下降.以上结果说明,磁性锆铁改性膨润土是一种非常有希望的用于控制河道底泥中磷释放的改良剂.