Mineralization of nitrogen after incorporation in soil of the main - PowerPoint PPT Presentation

Mineralization of nitrogen after incorporation in soil of the main types of animal manure produced in Cyprus Panagiotis Dalias and Dionysis Sparaggis Agricultural Research Institute, 1516 Nicosia, Cyprus

Nitrogen balance Supplied by soil Crop needs Fertilizers Synchronization

Providing N with manure is more complex than with inorganic fertilizers Provided by common Manure Ν chemical analysis Inorganic Ν Organic Ν (ammonium) After incorporation in ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ soil Mineralized Ν Residual Ν (non Volatilized Ν Remaining Ν decomposed + dead microbial biomass) Available Ν

The aim of the study Estimate the initial mineral N and the potentially mineralizable N of solid animal manure in relation to the stage of composting (storage) …as it is provided by mineralization curves shown by manure + soil mixtures incubated under controlled (optimum) conditions Provide if possible to farmers and relative authorities a standardized and tested procedure that is necessary in order to estimate N availability after manure incorporation in soil

Net mineralization shown after incubation at controlled conditions 100% 50% 0% 0 20 Time ( days)

Net immobilization shown in incubations of materials with high C/N ratio Nicolardot et al., 2004

Methodology ‐ approach 4 types of solid manure Bulk density Sampling every three months estimates Extractions with KCL and analyses of extracts Preparation of “manure + soil” Incubations at mixtures controlled conditions

Results Inorganic ‐ N at different stages of composting

0 months (fresh manure) Max Max mineralized immobilized soil 4 0 sheep 50 ‐ 5 cow 32 ‐ 5 pig 14 ‐ 26 poultry 38 0

3 months Max Max mineralized immobilized soil 5 0 sheep 0 ‐ 41 cow 29 ‐ 22 pig 2 ‐ 50 poultry 26 0

9 months Max Max mineralized immobilized soil 3 0 sheep 11 ‐ 3 cow 46 ‐ 6 pig 3 ‐ 13 poultry 74 0

Conclusions ‐ comments The duration of storage prior to incorporation in soil is important in controlling N mineralization rates Although during storage/composting C (and N) is lost, the use of fresh manure is not recommended because it results in strong N immobilization An early release that appears in very fresh materials is not synchronized with crop demand Net release of mineral N is shown after 6 months of manure storage/composting Results emphasize the need for preliminary trials if an effective use in agriculture is to be achieved

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