The SWAN system is composed of soil, water, atmosphere and nutrient components. The best way to show how these integrated and interrelated measures reflect the journey of improving agricultural sustainability is to show a case study of a farm which has become more sustainable over the past five years.
Nitrogen alone cannot carry the responsibilities of other nutrients in the plant. That is why farmers need to have a balance of all essential plant nutrients in order to archive optimal growth.
Approaching agriculture in new ways requires new perspectives on how to view things. One of the main differences between conventional and sustainable agriculture is the relative reliance on external inputs.
Due to a lack of soil health, and an imbalance in soil fertility, farmers are relying for too heavily on nitrogen fertiliser for pasture growth. This can actually lead to potassium loss from the soil.
We tend to focus on the localized environmental impact of nitrogen where it is applied, but what about the broader impact associated with its production?
There is a lot more nutrient cycling taking place than just what is put into the soil through fertiliser, and taken out in grass and eventually milk. In order to develop a more efficient nutrient cycling system, farmers have to take into account the various losses and sources of nutrients.
Nutrients are brought into the farm through the farm gate, and nutrients are removed through the farm gate. The question that needs to be asked is, are there more nutrients brought into, or removed from the farm system?
As to whether effluent is a waste or a benefit, depends entirely on how you, the farmer, use it.
A supply of nutrients and minerals to soils which is greater than the amount needed to maintain soil health and fertility actually endangers the soil and can negatively impact on surface and ground water sources.
Many nutrients are wasted on dairy farms due to oversupply through inputs from fertilizers and feeds. A great deal of nutrients, and therefore money, can be saved by recording and monitoring what nutrients are removed from the farm and what nutrients are brought onto the farm.