煤泥特性及其对砂性土物理性质的影响

The characteristics of coal slime and its influence on physical properties of sandy soil

【目的】了解煤泥特性及其对砂性土物理性质的影响,挖掘煤泥在农业上的利用途径。【方法】在分析煤泥特性的基础上,通过不同煤泥施用量0(CK)、15 t/hm^(2)(L-1)、45 t/hm^(2)(L-2)、75 t/hm^(2)(L-3)和135 t/hm^(2)(L-4)的无植物模拟培养试验,分析施用煤泥后,砂性土物理性质的变化。【结果】煤泥镉、汞、铅、铬、砷5类重金属含量低,仅占标准规定值的0.32%~11.55%;黏粒和粉粒高达73.43%;富含促进植物生长的有益元素SiO_(2)、Al_(2)O_(3)(相对含量共71.17%),含植物必需大量元素K_(2)O和P_(2)O_(5)(相对含量共2.02%),含植物必需中量元素CaO、SO_(3)、MgO(相对含量共18.00%),含植物必需的微量元素Fe_(2)O_(3)、MnO、ZnO、CuO、NiO(相对含量共6.73%),有利于植物的生长;总有机碳含量较高,为240.5 g/kg,轻组、重组有机碳比约为1∶4。施用煤泥可优化砂性土的粒级组成,增加砂性土黏粒(d<2μm)和粉粒(2~50μm)含量,增加幅度分别为1.01~4.95个百分点和0.21~0.71个百分点;提高了砂性土毛管孔隙比例,增加幅度为2.29%~16.46%;降低了砂性土的非毛管孔隙比,降低幅度为1.12%~45.42%;增加了砂性土的有效水含量,提高幅度为1.04%~18.89%。与CK相比,L-3和L-4处理均显著增加砂性土内黏粒、粉粒含量和显著降低砂性土容重(P<0.05)。L-3处理土壤毛管孔隙比例最高,为24.90%;土壤非毛管孔隙比例最低,为6.31%;土壤有效水占失水比例最高,为75.27%。【结论】煤泥重金属含量低,符合《城镇污水处理厂污泥处置土地改良用泥质》的安全指标特性,具有较高的保水性能,富含多种元素,可提供充足的有机碳;对砂性土的物理性质有较好的改善作用,在试验范围内施用煤泥量为75 t/hm^(2)时效果最佳。

【Objective】To understand the characteristics of coal slime and its impact on the physical properties of sandy soil,and to explore the utilization of coal slime in agriculture.【Methods】On the basis of examining the features of coal slime,using unplanted simulation culture experiments with varying application rates of 0(CK),15 t/hm^(2)(L-1),45 t/hm^(2)(L-2),75 t/hm^(2)(L-3)and 135 t/hm^(2)(L-4),the changes in physical properties of sandy soil following the application of coal slime were examined.【Results】The content of cadmium,mercury,lead,chromium,and arsenic in coal slime was low,accounting for only 0.32%to 11.55%of the standard values,with up to 73.43%of clay and powder particles.It was rich in plant growth promoting beneficial elements,SiO_(2) and Al_(2)O_(3)(with a relative content of 71.17%),contained essential macroelements K_(2)O and P2O5(with a relative content of 2.02%),essential medium elements CaO,SO_(3),MgO(with a relative content of 18.00%),and essential trace elements Fe_(2)O_(3),MnO,ZnO,CuO,NiO(with a relative content of 6.73%),all of which were beneficial for plant growth.At 240.5 g/kg,the content of total organic carbon was high.The ratio of light and heavy fraction organic carbon was around 1∶4.Applying coal slime optimized the particle size composition of sandy soil and increased the content of clay particles(d<2μm)and powder particles(2~50μm)with increases of 1.01-4.95 percentage points and 0.21-0.71 percentage points respectively.The proportion of capillary pores in sandy soil increased by 2.29%to 16.46%.The non capillary pore ratio of sandy soil reduced by 1.12%to 45.42%.The available water content of sandy soil increased by 1.04%to 18.89%.Compared with CK,both L-3 and L-4 treatments significantly(P<0.05)increased the content of clay and powder particles in sandy soil and significantly reduced the bulk density of sandy soil.L-3 treatment had the highest proportion of soil capillary pores of 24.90%,lowest proportion of non capillary pores of 6.31%and the highest proportion of soil available water to water loss of 75.27%.【Conclusion】Coal slime had low levels of heavy metals and met the safety index criteria of Soil Quality for Land Improvement of Urban Sewage Treatment Plant Sludge Disposal,with high water retention capacity,rich in various elements,and could provide sufficient organic carbon.It had good improvement effects on the physical properties of sandy soil.Within the scope of the experiment,the best effect achieved when the amount of coal slime applied at 75 t/hm^(2).