|JUNG, WONKYO - NIAST-RDA, KOREA
|ANDERSON, STEPHEN - UNIVERSITY OF MISSOURI
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2006
Publication Date: 1/25/2007
Citation: Jung, W., Kitchen, N.R., Anderson, S., Sadler, E.J. 2007. Crop management effects on water infiltration for claypan soils. Journal of Soil and Water Conservation. 62(1):55-63.
Interpretive Summary: About 10 million acres of claypan soils are found in the U.S. Midwest. The sub-surface “claypan” of these soils causes them to generally have very slow water infiltration which increases surface water runoff. Little is known how different crop management practices affect infiltration on these soils. Identifying water infiltration properties as affected by different crop management systems can provide crucial information to help plan for more profitable and more environmentally-sensitive practices for these soils. Further, better estimates of how management affects water infiltration can be used to improve simulation models for predicting runoff in claypan soil watersheds. The goal of this research was to compare the effect of annual grain cropping systems (e.g., corn, soybean, wheat) with perennial systems (e.g., cool season grass in a USDA Conservation Reservation Program (CRP) or a hay crop) on water infiltration for claypan soils. A second goal was to examine the relationships between various claypan soil properties [like soil organic matter and soil apparent electrical conductivity (EC)] with water infiltration parameters. We found that water infiltration parameters were considerably greater with perennial systems than with annual grain cropping systems, and greatest with the perennial hay cropping system. We attribute greater infiltration with this system in part to stimulated plant growth with biomass removal with the hay crop and to N fertilization. In addition, lower soil water content for the perennial cropping systems increased water infiltration. Within grain cropping systems, infiltration parameters were not different among tilled and no-till cropping systems. Water infiltration parameters were negatively correlated with initial soil water content and positively correlated with soil organic carbon. An increase in soil organic carbon with growing perennial plants is similar to what others have found. We also found improved soil aggregation with the perennial systems. In effect, it appeared that decreasing soil water content over the growing season and increasing soil organic carbon due to the perennial grasses increased soil water infiltration. Sensor-measured soil EC in the field was also found to be highly correlated with infiltration parameters. Since labor and time restrict characterization of water infiltration, this findings suggests that this sensor might be helpful in assessing variability of water infiltration. Characterizing water infiltration within and between fields will provide farmers and land managers with a basis for considering management strategies helpful in developing sustainable food and fiber production systems.
Technical Abstract: Plant water and nutrient use for claypan soils are restricted by an argillic horizon (clay content > 500 g/kg) that typically occurs 20 to 40 cm below the soil surface. Identifying water infiltration characteristics for claypan soils under different management provides crucial information needed to optimize crop management and estimate watershed hydrology. The objectives of the study were (i) to evaluate the influence of long-term annual cropping system (ACS) and perennial cropping system (PCS) management [such as conservation reservation program (CRP) and hay crop] on water infiltration and (ii) to develop relationships between claypan soil properties and water infiltration parameters. The effects of ACS and PCS management on water infiltration parameters were evaluated using ponded water infiltration measurements in the field. Water infiltration parameters were estimated based on field water infiltration measurements. Soil organic carbon (SOC) and aggregate stability were significantly (P < 0.05) improved after 12 years of CRP management compared to 12 years of ACS management. Antecedent soil water content and soil electrical conductivity (ECa) were lower and water infiltration was greater for PCS than for ACS. For a hay crop treatment (PCSc), water infiltration was greatly improved over that for any ACS or other PCS management treatments. Antecedent soil water content and SOC were significantly correlated with the water infiltration parameters. Soil ECa was significantly correlated with estimated saturated hydraulic conductivity (Ks). This relationship may be useful for mapping spatially-variable water infiltration within fields. In summary, perennial cropping systems contributed to improved water infiltration as well as to increase SOC and soil aggregate stability. Soil ECa may be useful for characterizing management influence on water infiltration without labor intensive sampling.