Experimental Study And Model Correction Of Soil Evaporation In Saline-alkali Soil Area

The soil in west of Heilongjiang province is mostly saline soil,mainly distributed in Daqing city and its surrounding areas.Soil salinity is the salt of the soil increases with the groundwater rise,due to evaporation of water,resulting in salt accumulation of soil surface,resulting in soil fertility decline or adverse to agricultural production.Maize is the main food crop in Daqing city and its surrounding areas.The sown area of maize in Daqing area is about 400,000 hectares every year,accounting for about 70 % of the total cultivated area of the city.Therefore,to study the evaporation law of bare soil and maize farmland soil in Daqing city and its surrounding areas,establish the calculation model of soil evaporation suitable for the region,which is of great practical significance to improve water efficiency of saline soil area,guide agricultural irrigation and alleviate soil salinization.(1)The bare soil test and field test based on Ritchie model were designed and completed.The experimental phenomena were given,test results were given,relevant meteorological data and soil physical properties index were given,which provided the foundation for studying of the Daqing saline-alkali soil area's evaporation law in bare soil.(2)Utilization of bare soil test results for the applicability of Ritchie model in saline soil area was evaluated,the correction method of Ritchie model was proposed,and the general versatility of Ritchie model was verified by test data.The second phase parameter of Ritchie model is obtained.The results show that calculated value of the Ritchie's model can coincide the evaporation measured value of bare soil in saline soil is well.(3)Analyzes the result of the whole process of maize growth and soil moisture content in saline soil region,establishes the relationship curve of soil evaporation with the change of moisture content,and analyzes the change law of soil evaporation and soil water content were got which under the condition of maize saline-alkali soil.(4)Further analysis the result of meteorological conditions of maize growth and evaporation of filed in saline-alkali soil region.For this result to fixed Ritchie model in evaporation of corn field which in Saline-alkali soil area,got the suitable values for the second stage of the Ritchie model with the seedling stage and jointing stage and male stage and grouting stage and mature stage.Utilize of field test data to verify the correctness of the Ritchie model,the results show that,the modify results of the maize field's Ritchie model are in good agreement with measured value,modify value of field's accuracy of Ritchie model is higher than bare soil.