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

Synchronization

Crop needs Supplied by soil Fertilizers

Providing N with manure is more complex than with inorganic fertilizers

Provided by common chemical analysis Manure Ν Organic Ν Inorganic Ν (ammonium) Mineralized Ν Residual Ν (non decomposed + dead microbial biomass) Volatilized Ν Remaining Ν Available Ν After incorporation in soil

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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

100% 50% 0% Time ( days) 20

Net mineralization shown after incubation at controlled conditions

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

Methodology ‐ approach Preparation of “manure + soil” mixtures Incubations at controlled conditions Extractions with KCL and analyses

• f extracts

Bulk density estimates Sampling every three months 4 types of solid manure

Results

Inorganic‐N at different stages of composting

0 months (fresh manure)

Max mineralized Max immobilized soil 4 sheep 50 ‐5 cow 32 ‐5 pig 14 ‐26 poultry 38

3 months

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

9 months

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

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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