【正文】
usts, and the morphological changes of soil crusts were observed by scanning electron microscope ( SEM) . The results showed that the control group after leaching for two times, the soil infiltration rate was stable at mmmin1. After adding magnesium oxide to the soil, the soil infiltration rate was significantly decreased to 0. 214 mm min1. When gypsum and magnesium oxide were bined added into soil column, the soil infiltration rate was stable at mmmin1 after leaching for two times, suggesting that the soil infiltration rate increased significantly after gypsum addition pared to that contaminated by magnesium oxide dust. The SEM diagram showed that the soil surface after adding gypsum exhibited a reticular structure and that the porosity and stability of the soil surface were improved, which would increase the permeability of the soil. Keyword:magnesite mining area。 penetration rate。 遼寧海城地區(qū)擁有豐富的菱鎂礦資源, 礦產(chǎn)資源給當?shù)貛斫?jīng)濟收益的同時也造成了嚴峻的環(huán)境污染。方玥蒙, 2016) .氧化鎂粉塵降落至礦區(qū)四周土壤外表, 自然條件下構成一層結皮, 降低當?shù)氐耐寥蕾|量 (郭芳, 1997) .在一些典型的菱鎂礦開發(fā)利用區(qū)域每年產(chǎn)生的含鎂粉塵多達14萬t, 礦區(qū)四周的土壤表層積累大量的粉塵在自然條件下構成堅硬致密的鎂質土壤結皮, 厚度最后可達10 cm (Kautz et al., 2001) .氧化鎂粉塵不僅能夠在土壤外表構成土壤結皮, 對海城菱鎂礦區(qū)的某塊廢棄地調查研究覺察, 土壤偏堿性較為嚴峻, 且隨著間隔礦區(qū)越近土壤的p H越大, 該地區(qū)土壤被菱鎂礦粉塵污染后p ~, 未被污染的土壤p (楊丹等, 2010) .鎂粉塵污染土壤不僅阻礙農(nóng)作物產(chǎn)量, 在污染嚴峻區(qū), 只有少部分的灌木和幼松樹存活 (Raman et al., 1993。物理修復主要以更換土壤為主, 例如, 劉綺等 (1998) 建議客土、翻土等物理方法修復鎂質污染土壤。但是, 海城地區(qū)礦區(qū)四周土壤污染面積較大, 采納物理修復方法其修復費用較高, 而且該方法僅適用于重度污染且修復迫切地點和污染程度較輕的農(nóng)田。王泓泉等 (2014) 研究了羊草、披堿草、剪股穎和堿茅對菱鎂礦區(qū)鎂粉塵污染土壤的修復效果時發(fā)如今被鎂粉塵輕度污染的土壤中4種植物對土壤鎂的去除才能較好。但是, 與物理修復及化學修復相比, 生物修復周期長, 見效慢。聚丙烯酰胺被認為是良好的土壤改良劑, 大量研究說明, 聚丙烯酰胺能保持土壤的構造防止分解, 提高土壤的浸透速率 (Ben et al., 1997。Sojka et al., 2007) .張心昱等 (2006) 研究磷石膏和豬糞混合施入污染土壤中覺察, 不僅能降低土壤的p H值, 還增加了水溶性鈣鎂比的值, 改良后的土壤對植物的營養(yǎng)供應更好, 張立軍等 (1995) 也證明, 施加磷石膏使得鎂污染土壤中玉米的發(fā)育情況也有所改善?! ”狙芯坎杉{土柱作為試驗淋洗裝置, 以干凈土壤進展淋洗試驗作為空白對照組;向土壤中添加定量的氧化鎂粉塵后在一樣條件下進展淋洗試驗模仿礦區(qū)土壤被氧化鎂粉塵污染后土壤浸透性變化;在干凈土壤中同時參加定量的石膏與氧化鎂粉塵后進展淋洗試驗調查石膏對氧化鎂粉塵污染土壤浸透功能的改良作用?! 〔牧吓c方法 試劑與儀器 石膏, 北京紅星化工廠, 粉末狀;供試的鎂粉塵為海城總廠消費的輕燒氧化鎂粉塵, 氧化鎂含量為97%, 粒徑大小約為5mu。p H測試儀 (上海雷磁PHS3C酸度計) 清潔土壤樣品 試驗土壤樣品采自海城市梨樹村農(nóng)田土壤 (0~15 cm) 表層土, 將土壤樣品于室內自然風干后過2 mm尼龍篩獲得小于2 mm的土壤顆粒備用, 測得土壤的理化性質如表1所示。土柱內徑5 cm, 土壤填充高度約15 cm, h后進展土壤淋洗試驗, 初次淋洗完畢后將土柱自然晾干兩周后進展第二次淋