Location: National Soil Erosion ResearchTitle: Tillage system and time post-liquid dairy manure: Effects on runoff, sediment and nutrients losses Author
|Huang, Chi Hua|
Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: The recent increase in confined animal production systems has triggered an increased land application of liquid manures. Liquid manures do have nutrients and, they may improve soil quality. Improper timing of the manure application may cause nutrient runoff and affect water quality. In this research, we collected soil blocks from fields that have been under long-term conventional tillage and no-till and measured runoff, sediment and nutrient losses from rainstorms one and 7 days after manure application. We found that conventional tillage resulted in higher losses than those from no-till system. The greatest fractions of nutrient losses were in the particulate fraction, indicating erosion as the primary process associated with nutrient loss. Timing of the first rainfall event after manure application affected runoff, sediment and nutrients losses. Rainfall occurred one day after the manure application resulted in higher losses in both conventional and no-till systems as compared to those from a rainfall event 7 days after manure application. In practical terms, we recommend using weather forecast in making decisions on when to apply liquid dairy manure to obtain agronomic benefits and avoid risk of water pollution.
Technical Abstract: Liquid manure applied in agricultural lands improves soil quality. However, incorrect management of manure may cause environmental problems due to sediments and nutrients losses associated to runoff. The aims of this work were to: (i) evaluate the time effect of post-liquid dairy manure (LDM) application on runoff, sediment and nutrient losses; (ii) compare the effect of conventional tillage and no-till systems on runoff, sediment and nutrient losses after LDM application. A rainfall simulation experiment was conducted on intact soil blocks collected from fields that had been under conventional tillage and no-till systems. Rainfall was applied 24 hours and 7 days after LDM application. Conventional tillage without manure application resulted on higher runoff, sediment and nutrient losses (mainly the particulate fraction) than no-till without manure. The greatest runoff, sediment and nutrient losses occurred in the treatments where simulated rainfall was performed 24 hours after LDM application independent of the tillage system. An interval of 7 days between manure application and the simulated rainfall reduced mainly, sediment, particulate P, and particulate N losses in both conventional and no-till systems. In practical terms, we would recommend a minimum of 7 days between LDM application and rainfall-runoff event to provide agronomic benefits minimizing the potential risk of water pollution.