Laboratory Exercises to Demonstrate Effects of Salts on Plants and Soils

Abstract

The presence of salts in soil or in irrigation water can adverselyaffectplantgrowthandsoilproperties.Salinityconcerns are more common in semiarid and arid regions than in more humid regions. Furthermore, salinity is often an important concern for irrigated agriculture. Therefore, it is critical to educate students in soils courses about the effects of salts on plants and soils. Many soils laboratory manuals focus on measurement of salts in soils, but few include demonstrations of how salt effects bothplantsandsoils.Demonstratingtheeffectsofsaltsonplants andsoilsshouldenhancelearningbyprovidingtangibleimages. Our purpose was to develop laboratory exercises that demonstrate these effects for use in soils and other science courses. To demonstrate differences in plant response to salinity, a hydroponic study utilizing a range in salinities and plants with differentsaltsensitivitieswasused.Todemonstratedifferencesinhow salteffectshydraulicconductivity,astudyutilizingthreesoilsand foursaltsolutionswasused.Theseprovidevisualrepresentations of the well-established effects of salts on plants and soils. Includingplantspecieswithdifferentsalttolerances,soilswithdifferent textures, and treatments such as elevated sodium and elevated total salt levels effectively demonstrate the relative importanceofsalts.Inclusionofthesevisualdemonstrationsofthe effects of salts on plants and soils should enhance student learning.