Location: Soil Dynamics ResearchTitle: Measuring the effects of different manure sources on soil erosion utilizing a portable rainfall simulator
|HORVATH, T - Natural Resources Conservation Service (NRCS, USDA)
|Torbert, Henry - Allen
Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2023
Publication Date: N/A
Interpretive Summary: Soil erosion models are being used to predict the influence agriculture has on sediment loss from current farming practices. However, not all scenarios used in these models have been thoroughly validated under field conditions because it is almost impossible to evaluate all situations. Thus, assumptions are often used to fill information gaps. For example, manure application is credited in these models for increased surface coverage but is not accurately adjusted for its actual influence on sediment loss. Thus, a study was conducted to evaluate the influence of manure application on runoff amount, soil erosion, and N and P loss using a rainfall simulator. Sediment loss and runoff amounts were reduced with following manure applications regardless of the source. However, dissolved P and N loss tended increase in runoff water samples following manure application when compared to no amended soils.
Technical Abstract: Soil erosion models are becoming increasingly accurate and now can simulate a variety of surface covers which can lessen erosion by reducing detachment and movement of soil particles. Currently, there is limited data on the effects of animal manure on soil erosion. Most process models credit animal manure as crop residue cover. Thus, there is a need for bench studies under laboratory conditions, as well as field studies to determine the effects manure applications have on runoff and sediment loss. Thus, rainfall simulation studies were conducted to evaluate the influence of different animal manures on runoff, sediment yield, and nutrient loss using undisturbed soil monoliths placed in perforated trays. The soil was collected from fields managed under long-term no-till and conventional till for over 15 years. Poultry litter, solid dairy manure, liquid swine manure, liquid dairy manure applied to the experimental units were compared to a no manure treatment. Sediment yield and runoff amounts were reduced following manure application regardless of source, with reductions generally occurring with increasing rates. Sediment yield tended to be higher in conventional till vs. no-till; however, the addition of manure tended to be more effective at reducing sediment loss with conventional till. Dissolved reactive P, NH4-N, and NO3-N levels in the runoff effluent increased for all of the manure sources with increasing rates. These results suggest that manure applications can reduce soil loss, especially from the conventionally-tilled treatment.