王文达　兰敬芳

摘要 以内蒙古河套灌区为背景对耕地与盐荒地盐分变化展开研究。在野外实测和实验室检测数据的基础上，分析多因素影响下耕地和盐荒地盐分变化规律。结果表明，盐荒地和耕地0～100 cm土层中都含有60～80 meq/100 g的非水溶性钙盐，而盐荒地水溶性盐的含量明显升高。年度变化显示，耕地可溶盐年均提高了4.46%；盐荒地可溶盐年均提高了4.48%；耕地非可溶盐年均提高了2.99%；盐荒地非可溶盐年均提高了3.87%，灌区每年灌溉水带入的盐分有少量在盐荒地中积聚。盐分变化对作物生长的影响以及发展改良措施具有重要意义，为灌区水盐管理提供科学依据。

关键词 内蒙古河套灌区；耕地；盐荒地；土壤盐分

中图分类号 S156.4 文献标识码 A 文章编号 1007-5739（2017）03-0156-03

Abstract This paper studied the salinity variation of cultivated land and salt wasteland in Hetao Irrigation District in Inner Mongolia.Based on the field data and laboratory testing data，the paper analyzed the change rule of salinity in cultivated land and salt wasteland under multi-factor influence.The results showed that the 60～80 meq/100 g non-water-soluble salt Ca existed in 0～100 cm soil layer both in salt wasteland and cultivated land while the content of water-soluble salt in the wasteland increased significantly.The annual change showed that the water-soluble salt in the cultivated land increased by 4.46% annually，while the data in the salt wasteland was 4.48%.The non-water-soluble salt in the cultivated land increased by 2.99% annually，while the data in the salt wasteland was 3.87%，which meant that a small amount of the salt brought by the irrigation water into the irrigated area accumulated in the salt wasteland.The salt variation is important to the crop growth and draft of improving measures.It can provide scientific basis for the management of soil moisture and salt content in the irrigated area.

Key words Hetao irrigation district in Inner Mongolia；cultivated land；salt wastelend；soil salinity

1 试验区概况

内蒙古河套灌区位于干旱、半干旱地区，总控制面积达11 190 km2，是全国三大灌区之一[1]，灌溉面积5 743 km2 [2]，盐荒地面积8.76 km2。降水多集中在6—8 月，年降水量139～222 mm，年蒸发量2 200～2 400 mm。蒸降比在10以上[3-5]。灌区年均地下水埋深1.24～1.79 m[6]。试验于2004—2009年在内蒙古河套灌区沙壕渠试验站光荣二队试验地进行，试验期为每年4月末至10月初，选择耕地间隙分布的盐荒地，荒地面积1 497.6 m2。试验田土壤质地为粉质黏壤土，平均干容重为1.466 t/m3。

2 试验内容与方法

2.1 地下水水位与水质的观测

共设3个观测井，孔深4 m，用于观测地下水埋深和获取水样（图1），用速测仪测定水质样的 EC值（图2）及pH值，孔以距离南侧地堰的距离命名分别为D5、D10、D15号孔。

2.2 土壤盐分测定

采用田间取土，试验室自然风干以1∶5土水混合提取液速测EC值、pH值和全盐量（八大离子：CO32-、HCO3-、Cl-、SO42-、Ca2+、Mg2+、K+、Na+）的测定[7-9]。……