脱硫石膏与灌溉耦合对滨海盐碱土化学性质的影响

Effects of Coupling of FGD Gypsum and Irrigation on Chemical Properties of Harbor Front Saline Soil

脱硫石膏(CaSO4.2H2O)是火力发电厂石膏湿法烟气脱硫的副产物。对盐碱地施用脱硫石膏可以通过Ca2+置换盐土中的Na+,达到脱盐目的。通过盆栽试验研究天津滨海盐土施用脱硫石膏并配合灌溉淋洗改良盐碱土的效果。结果表明:对于表层土壤(0-10cm),施用脱硫石膏对Ca2+、Mg2+、K+、Na+、Cl-、SO24-离子含量有显著降低作用。10cm以下土壤,脱硫石膏的脱盐能力与施用量呈正相关。脱硫石膏与灌溉耦合时,脱硫石膏施用量为3 000kg/hm2以上时改良效果较好。随着脱硫石膏施用量的增加不但降低了土壤Na+含量与土壤pH值,对灌溉量的需求也有所降低。灌溉量为田间持水量的80%时脱硫石膏对土壤Ca2+、Mg2+与K+的降低作用与CK相比差异最显著。脱硫石膏施用量的增加提高了土壤全盐量,但随灌溉量增加这种影响逐渐降低。

FGD gypsum（CaSO4·2H2O） is a byproduct of the flue gas desulfurization.It can achieve demineralization by exchanging Na＋ with Ca2＋.A pot experiment was conducted to study effects of FGD gypsum coupling with irrigation facts on chemical properties in Tianjin saline soil.Results indicate that after the application of FGD gypsum,there is a significant decline of Ca2＋,Mg2＋,K＋,Na＋,Cl-and SO2-4 in the upper layer of soil（0-10 cm）.The desalinization ability in the lower layer of soil（10 cm）has a positive correlation with the amount of the FGD gypsum applied.Coupling of FGD gypsum and irrigation indicates that an application rate more than 3 000 kg/hm2 of FGD gypsum can achieve a better result of desalinization.An increase of application of FGD gypsum will decrease Na＋ and the soil pH value at a lower irrigation requirement.An irrigation level at 80% of the field capacity will lead to the most significant difference of Ca2＋,Mg2＋,K＋ between a FGD gypsum treatment and the control group.The FGD gypsum treatment will increase the soil salt content value,but the effect will be lessened with the increase of irrigation.