An Inexpensive and Simple Method to Demonstrate Soil Water and Nutrient Flow

Abstract

Soil quality, soil health, and soil sustainability are concepts that are being widely used but are difficult to define and illustrate, especially to a non-technical audience. The objectives of this manuscript were to develop simple and inexpensive methodologies to both qualitatively and quantitatively estimate water infiltration rates (IR), water-holding capacity at saturation (WHC_s), and potential nitrate-nitrogen (NO₃–N) loss and to test the accuracy and precision of these methods. Complete details for how to assemble the appropriate supplies and conduct the measurements are provided, but for demonstrative purposes these methods do not need to be followed in detail, particularly using the various equations to get quantitative values. In the field and classroom, these demonstrations have been well received by non-technical and technical audiences and have been performed by request as well as incorporated into agronomy classes for high school and college students and training for agriculture educators. In the laboratory, these methods were tested on 10 benchmark soils and values were compared with each other and soil aggregation as measured by dry soil aggregate distribution and water stability. In these benchmark soils, IR and WHC_s increased with a reduction in soil disturbance and more continuous plant cover due to diverse crop rotation and perennials while NO₃–N loss was highest in soils with synthetic fertilizer inputs, little plant cover, and more soil disturbance. These results indicate the methodologies outlined here may be used to demonstrate agroecosystem management's impact on soil health.