Nutrient Management Research Database
General Information
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Summary/Abstract from Original Source
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Design and Methods
This report summarizes the finding of two studies:
1) The release of nitrogen (N) and phosphorus (P) from a variety of organic materials including:
- Composted poultry manure
- Composted dairy manure
- Municipal compost
- Alfafa hay
- Commerical fishmeal organic fertilizer
Each of these materials was applied to both mulched and non-mulched plots
2) The study of nutrient cycling in soil under mulches and amendments. The amendments and mulches included:
- Alfafa hay mulch and dairy solids
- Spray on mulch
- Shredded paper mulch with biosolids
Results
Study 1 Results
Decomposition rates varied widely between the materials tested. Based on these values, the authors calculated the amounts of each material needed to supply 100 lbs N/ac in the first year after application:
Dairy Compost | Poultry Compost | Municipal Compost | Alfafa Hay | Fishmeal | |
Estimated N Content | 1.5 | 2.5 | 2.0 | 2.5 | 9.0 |
Loss in first year (%) | 12 | 33 | 36 | 53 | 65 |
Amount need to reach 100 lbs N/ac | 27 t/acre | 6.1 t/acre | 6.9 t/acre | 3.8 t/acre | 0.9 t/acre |
Relatively small differences were observed between mulched and unmulched soils.
Study 2 Results
Application of partially composted dairy solids in 2000 increased P availability in 2002. However, the presence of the alfalfa hay mulch decreased P availability in plots that also had added dairy solids.
Municipal compost application in 2001 increased P availability in 2002, whether or not mulch was applied. P availability was higher under drip irrigation than under sprinkler irrigation. However, drip irrigated plots showed reduced P availability when a mulch was also applied.
Increases in microbial P and enhanced nutrient cycling were observed when shredded paper mulch was added.