Type of organic manure being spread (e.g. cattle, pig, poultry or biosolids) The total N, readily available N and dry matter content of the manure. A laboratory analysis or on-farm test result is best, but if this is not available, MANNER has built-in 'typical' values Amount applied, either in metric or imperial units (e.g. tonnes/hectare or tons/acre) Date when the manure was spread Application method and whether incorporated into the soil (e.g. left on the surface or ploughed down after a given time) Soil type in the field Rainfall since spreading until the end of soil drainage (commonly about the end of March). local rainfall data should be entered, but if not known, MANNER has built in 'typical' values

MANNER ESTIMATES PLANT AVAILABLE NITROGEN SUPPLY BY ACCOUNTING FOR:

Ammonia losses to air

The ammonium (readily available) N content of manures can easily be lost to the atmosphere by ammonia volatilisation. To reduce losses: Manures can be rapidly incorporated into the soil Slurries can be applied using injection or band spreading methods

Nitrate leaching losses to water

Where there is sufficient rainfall following manure application to land, nitrate may be leached beyond crop rooting depth. Losses are potentially greatest from slurries and poultry manures, which contain larger amounts of readily available N than straw-based farmyard manures. The amount of N loss depends on:     -manure application rate     -rainfall volume after application     -soil type

Organic N release

The organic N content of manures is gradually released (mineralised) and becomes slowly available to crops over a period of months to years.