There are several strategies through which the negative effects of animal feed ingredients on crop nutrients can be minimized. We will be looking at some of those strategies. But before doing so, there are several basic things we need to acquaint ourselves with. Those include:
The animal feed ingredients: these turn out to be the ingredients used in making the feeds that are administered (to farm animals) by the farmers who practice animal husbandry. Most of these feeds originate from farm products, such as corn and soybeans. As such, they have nutrients derived from the soils where the farm products used in making them were grown. Such nutrients, which also turn out to be of relevance as crop nutrients include things like Nitrogen (in the form that is absorbable by plants) and Phosphorous.
Crop nutrients: these are the nutrients that crops need for their well-being, seeing that the crops (plants) are also living things which require nutrients. Worth noting about the nutrients in question here is the fact that they are required in optimal levels: neither too much, nor too low.
The negative effects
The negative effects of animal feed ingredients on crop nutrients start manifesting when the crop nutrients in such animal feed ingredients seep into the soil (when the nutrients are excreted as manure).
If crops are to do well, they need optimal levels of various nutrients. To ensure this, farmers subject their soils to chemical analysis, where the right levels of various nutrients are figured out. They proceed to supplement what is there through chemical fertilizers. But should such soils get even more of the nutrients that were artificially supplemented through things like nutrient-containing manures washed into the farms, you’d end up with an oversupply of the said nutrients. That would hamper productivity. That situation, where animal feed ingredients end up interfering with crop nutrients is clearly undesirable. This is what makes it necessary to avoid such scenarios through among other strategies:
1. Legislation: that is where, for instance, we have seen jurisdictions like Ontario in Canada passing legislation (by the name of Nutrient Management Act) to combat the whole scenario. This ends up being beneficial to not only the farmers involved in crop husbandry, but also the general public. The latter assertion is due to the fact that these nutrients that seep out of animal manure have an effect on things like groundwater resources, whose mineral levels they can alter. That is as in the case of something like Phosphorous seeping into groundwater resources.
2. Animal feed ration optimization: this is where, for instance, certain nutrients can be added to rations (in refined/synthetic form), thus increasing the uptake of things like nitrogen and phosphorous, and hence reducing the amounts of nitrogen and phosphorous excreted. When dealing with monogastric animals, for instance, the increased supply of phytates can be useful in that regard — to the extent that it can reduce phosphorous excretions. Under this scheme, it is also possible to reduce the amount of nitrogen that is excreted as manure and which ends up in the soil, by simply reducing (or rather optimizing) the supply of proteins. This ensures that the animals only get the protein they need, which means that little or no nitrogen-rich protein is excreted.