Dynamics of Soil Infiltration Rates in Various Agroecosystems.

Dynamics of Soil Infiltration Rates in Various Agroecosystems

Landon M. Gibbs and Iin P. Handayani
Murray State University, Hutson School of Agriculture

Abstract
The evaluation of infiltration rates is vital to estimate surface runoff in order to reduce the risk of pollutant contamination and to efficiently apply water and fertilizers for a crop’s benefit. The objectives of this study were (1) to assess the impacts of six agroecosystems on infiltration rates; (2) to observe the temporal variability of soil infiltration rates under various seasons (fall-spring-summer-fall); and (3) to quantify the relationships between soil infiltration rates with other properties including soil organic carbon (SOC), macroaggregates, and bulk density. The study was conducted in Calloway County of western Kentucky using six agroecosystems. They were no-till corn, conventional tillage soybeans, conventional tillage tobacco, organically grown vegetables, woodland, and prairie. All of the soils used in this study have a silt loam texture. The infiltration rates were measured using a single ring infiltrometer. Soil organic carbon (SOC) was measured using the loss on ignition (LOI) method. Macroaggregates and bulk density were determined using wet sieving and ring methods, respectively. The data was statistically analyzed using ANOVA followed by the least significant difference (LSD) test at α 5%.The results show that organic farming and woods have the highest infiltration rates (36 to 95 cm/hr) followed by prairie (14 cm/hr), no till corn ( 12cm/hr) and the conventional tillage systems (4.5cm/hr). The values of infiltration rates were closely correlated to SOC (r²= 0.99) and macroaggregates (r²=0.88). More results will be discussed in the presentation.

Key words: Bulk density, infiltration rate, Kentucky, macroagrregates, soil organic carbon