河套灌区土壤盐碱化发生气象预测指标探析

Analysis for Meteorological Forecasting Indices of Soil Salinizational Process in Hetao Irrigational Area

【目的】利用气象部门观测优势,建立气象资源要素参与的土壤盐碱化生产决策模式,在分析河套灌区土壤盐碱化发生气象条件的基础上,探求土壤盐碱化气象预测指标。【方法】依据"盐随水移"的原理,主要运用内蒙古达拉特旗国家气象观测站2017—2018年0~50 cm土体土壤水分定点观测日数据以及相应时段的气象观测资料,以方差分析和相关分析方法对土壤水盐垂直运移的气象条件与动力作用进行分析。【结果】灌区内不同气象站点间的多年平均综合气象环境状况无显著差异。0~50 cm耕作层土壤水分垂向运移的全年动态以向上蒸发为主,且0~40 cm土层的土壤水分在0—23:00时24个时次间的蒸发动态,具有明显的时序特征。气象环境诸要素中,日照时数、气温与地温3个气象指标与0~50 cm土层土壤含水率变化的正相关性最为显著。【结论】热力条件是土壤水盐垂向蒸发的关键性动力因素。降水是土壤水盐垂向下渗的主要气象动力因子。夏秋季持续发生一周以上较为连续的大于40 mm的集中性降水,是河套灌区气候要素抑制土壤盐碱化发生的预测指标。促成土壤盐分从30~40 cm及其以上的土层,淋洗运移到40 cm耕作层以下的降水持续时间为20 d左右。

【Objective】The objective is to analyze the meteorological conditions of soil salinization in Hetao Irrigation Area,and explore meteorological indices for prediction of soil salinization,and furthermore,onpurpose to use meteorological observing advantages of meteorological departments,and to establish Agricultural production decision model involving meteorological resources on problem of soil salinization,and reduce effects of salinizational disaster on agricultural production.【Method】Based on the principle of"salt shifting with water",meteorological conditions and dynamic effects on vertical migration of soil water and salt been analyzed by the methods of ANOVA and correlation analysis with using the daily meteorological observation data of 0~50 cm soil moisture and the meteorological condition from 2017 to 2018 at the National Meteorological Observatory of Dalate Banner of Inner Mongolia.【Result】The results show that(1)there is no significant difference in annual comprehensive meteorological environment between meteorological stations in Hetao irrigation area.(2)the upward evaporation was the main dynamic of vertical migration of soil water in plough layerof 0~50 cm in the whole year;(3)the soil water contentsin 0~40 cm layersare significantly different between 0~23 o’clock,and this indicatesanobvious chronological characteristics of evaporation;(4)among factors of the meteorological environment in the irrigation area,thatis most significant that sunshine hours,air temperature and ground temperature have a positive correlation with soil moisture content in 0~50 cm layers.【Conclusion】Thermal condition is the key to drive vertical evaporation of soil water and salt.The continuous precipitation more than 40 mm in the summer and autumn is main meteorological factor in seeping process of soil water and salt.It is about 20 days that soil salt penetrate from soil layer of 30~40 cm to 40~50 cm of tillage layer or below it.