|Loecke, T - DEPT OF AGRONOMY, ISU|
|Liebman, M - DEPT OF AGRONOMY, ISU|
|Richard, T - DEPT AG&BIOSYSTEMS, ISU I|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2003
Publication Date: January 29, 2004
Citation: Loecke, T.D., Liebman, M., Cambardella, C.A., Richard, T.L. 2004. Timing of application and composting affect corn (Zea mays L.) and yield response to solid swine (Sus scropfa L.) manure. Agronomy Journal. 96:214-223. Interpretive Summary: Swine production in open-ended hoop structures is an emerging alternative swine management strategy in the upper Midwest. One advantage of this type of system is that the manure/bedding material can be easily removed for composting prior to field application. Composting reduces the volume of material and simplifies transport costs but also results in the loss of nutrients and carbon. Using fresh and composted manure from hoop structures, this field study evaluated the impact of manure form (composted or fresh) and timing of application (spring or fall application) on corn yield for a site in central Iowa in 2000 and 2001. Corn yield for 2000 was the same whether the swine manure was fresh or composted. In 2000, corn yield was also unaffected by timing of application. However, in 2001, corn yield was highest when the amendments were applied in the fall. In addition, in 2001, composted manure produced greater yields than the fresh manure. The results show that crop response to manure application is inconsistent from year to year, even though the amount of applied manure N remains the same. The results also illustrate the importance of multi-year data collection in the field. This information will be useful to researchers and farmers interested in using composted manure in corn-soybean production systems and will impact compost management decisions in these systems.
Technical Abstract: Swine production in hoop structures is a relatively new swine husbandry system in which a mixture of manure and bedding accumulates. This manure/bedding pack can be applied to crop fields directly from the hoop structure or piled for composting. During 2000 and 2001, field experiments were conducted near Boone, IA, to determine the effects of time of application (fall or spring) and form of manure (fresh or composted) on corn (Zea mays L.) and soil N parameters and corn grain yield. Fresh and composted manure were applied at a total N rate of 336 kg N ha-1. These treatments were augmented with four urea-N fertilizer treatments (0, 60, 120, and 180 kg N ha-1) to determine N fertilizer equivalency values for the organic amendments. In 2000, but not in 2001, fresh hoop manure decreased corn emergence. In 2000, no corn yield differences were detected due to the form or the time of manure application, but all amended plots yielded higher than the unamended control. In 2001, fall application of amendments increased corn grain yield more than spring application and composted manure increased corn grain yield more than fresh manure, with spring-applied fresh manure providing no yield response beyond the unamended control. Mean N supply efficiency, defined as N fertilizer equivalency as a percentage of the total N applied, was greatest for fall-applied composted manure (34.7%), intermediate for fall-applied fresh manure (24.3%) and spring-applied composted manure (25.0%), and least for spring-applied fresh manure (10.9%). Based on these results, the optimum management strategy would be to apply composted manure in the fall. Possible losses of N and economic impacts associated with the time and form of application need to be evaluated and could affect these recommendations.