On traditional small-scale mixed family farms with crop and livestock production, nutrients in livestock excreta are mostly utilised on the owned land.
With this recycling of the nutrients, the system is more or less closed and emissions resulting from excessive manure use or manure discharge are negligible.
However, with the establishment of large specialised livestock production farms the nutrient cycle is often disrupted as either the excreta can no longer be used on the farms’ own land (landless farms or farms with insufficient crop land) or because a good manure and nutrient management is considered to be economically unfeasible.
The livestock excreta is often discharged into watercourses or applied in excessive quantities to land close to the animal houses, which causes accumulation in the soil and high emissions into water and atmosphere.
The problem is specially pronounced on pig and poultry farms which, unlike cattle production, often grow none of the feed themselves.
The concept of area-wide integration between specialised livestock and crop farms (AWI), aims to re-establish the balance between livestock and crop production on a regional level.
One important step to achieving this is the contractual utilisation of manure from specialised livestock farms on surrounding crop farms.
Thus, the nutrients and organic matter in excreta are again recognised as resources which help to reduce mineral fertiliser input of agriculture and the environmental impact of livestock production.
Such a practice needs detailed planning and reliable tools and recommendations for farmers and extension officers.
Reliable tools are also needed by public institutions to assess the environmental impacts through nutrient surpluses and emissions of agriculture.
The calculation model NuFluxAWI is such a tool which:
quantifies the nutrient and heavy metal excretion of livestock (especially pig and poultry),
quantifies the amount and the composition of different types of pig and poultry manure produced,
quantifies the nutrient demand of crops,
calculates the balance between nutrients in manure and other fertilisers on one hand, and nutrient demand of crops on the other,
allows fertiliser calculation plans for distributing manure to different crops and complementing it with mineral fertilisers.
NuFluxAWI was designed to allow user-friendly calculations at the regional and the farm level.