Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #299787

Title: Surface compost effect on hydrology: In-situ and soil cores

Author
item Logsdon, Sally
item Malone, Robert - Rob

Submitted to: Compost Science and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2014
Publication Date: 11/12/2014
Publication URL: http://handle.nal.usda.gov/10113/59850
Citation: Logsdon, S.D., Malone, R.W. 2014. Surface compost effect on hydrology: In-situ and soil cores. Compost Science and Utilization. 23:30-36.

Interpretive Summary: Adding compost to the surface of urban soil helps the soil hold water, and increases the volume of larger pores in the surface. The large pores increase the rate water and air can enter the soil, and often improves turf growth. This study showed that compost added to the surface increased the amount of water held in the surface soil, but did not affect the amount of water in the subsoil. Water entered the soil faster when there was compost at the surface. The data are of interest to scientists who study urban soil and to landscape ecologists who want to increase the rate water enters and is retained in urban landscapes.

Technical Abstract: Compost increases water-holding capacity and total porosity. Improved soil structure may increase volume of macropores, allowing better drainage, air exchange, and root growth. The purpose of this study was to compare water retention curves and hydraulic conductivity for packed columns with and without additions of surface compost. Columns packed with subsoil (around 60 cm long) had either compost or topsoil added to the surface. Tensiometers and hydra probes monitored soil head and water content during three wetting and evaporation cycles. The columns with compost had significantly smaller bulk density at the surface than columns with topsoil (0.87 vs. 1.34 g cm-3). Surface compost amendment resulted in more water when satiated (0.617 vs. 0.422 m3 m-3) and at -100 cm head (0.377 vs. 0.276 m3 m-3) than for topsoil at the surface, indicating a greater fraction of larger pores for the compost amended. Whole column infiltration rate was significantly faster for columns with compost than without (1.46 vs. 1.11 cm min-1); however, saturated hydraulic conductivity on soil cores was not significantly affected by compost. Subsoil hydrology was not significantly affected by surface compost. For the subsoil, in-situ column desorption was significantly drier than core desorption at the wet end. There were no significant differences in whole column or surface water retention or evaporation rate. Perhaps the trend towards better water-holding capacity in the compost treatment was offset by larger pores and faster drainage, resulting in no significant difference between compost and topsoil.