[ 17/June/22 ]
Feedlots, in and of themselves, are not the problem.
If done well, feedlots can eliminate the problem.
If done badly, they can make the problem worse.
The issue is not feedlots in and of themselves as a concept, it is how the specifics of the particular system actually operate.
The issue of nitrate pollution of groundwater from intensive dairy has two major aspects to it:
One is that cows tend to stand still when they pee, and they drop quite a few liters of urine in one spot on the ground. This is more urine than the plants in that place can rapidly use, so if there is a rain event, then some of that nitrogen can get flushed through the root zone of the soil and enter the groundwater system. Putting cows in feed lots means that we can capture all of that urine (and other waste products – faeces, methane, whatever) and treat them appropriately, before returning them to the pasture system in appropriate concentrations such that they are used effectively by the pasture. There is no guarantee that a feedlot system will do that well, but there is potential for it to be done far more efficiently and effectively than is possible with any form of open pasture grazing system. And there are a lot of ways to do it badly.
The second major class of issues for groundwater (and to a degree surface water runoff) pollution by nitrates is nitrogen forcing production. One of the many influences on plant growth is the concentration of available nitrogen near the plant roots. If this is high, then it tends to promote plant growth. The issue with running high nitrogen levels throughout the soil profile where the plant roots are is that any excess of water in the soil system will tend to push some of that nitrogen below the lowest of the roots and into groundwater. One of the issues with soil is that it is never a perfectly homogenous thing, it is variable at every scale you look at it. So that it doesn’t matter how perfectly you try to apply water to a soil profile, there will always be places where it flows through faster than you want it to, and other places where it goes too slow (so some areas deep in the soil will be too dry, and others too wet as against the optimum you are trying to achieve – if in fact the operator is trying to achieve the optimum for minimum environmental impact, as against simply going for maximum production at minimum cost). Perversely, attempts to “optimise” water use, tend to make this aspect of the problem much worse, as when such flushing to groundwater events happen, they tend to be small and at high concentration, rather than large and at lower concentration. Lowering the amount of free nitrogen in the soil does reduce the the total protein production of the pasture. However it is done, there must be an acceptance of some degree of reduced productivity or increased water use (by injection of flushing flows below the root zone on an as required basis), if groundwater nitrate levels are to be kept low (and by low I mean below 1, not below 7).
So the “problem space” of humans and ecosystems coexisting is deeply complex, and if feed lots are done well, then they can be part of an effective solution to the problem of ground water pollution, and it is also true that doing feedlots well is not simple, and there are many more issues of animal welfare that need to be effectively addressed than simply looking at groundwater pollution.
So no – I cannot be against feedlots as a concept.
Going backwards to low productivity technologies actually requires more land area, and thus in the big picture leaves less opportunity for natural systems – if we are to feed the people we have.
We need high tech, and high tech by itself can just mean bigger problems if it is not done in ways that do actually manage all of the potential issues effectively. Left simply to market incentives, then yes, feedlots create massive environmental issues if they are being simply optimised for maximum output at minimal cost.
If however, feedlots are used with a lot of very high technology that is constantly monitoring and adjusting and optimising for maximal animal welfare, minimal environmental impact and producing a profit, then they can be orders of magnitude less impact than any form of pasture production, simply because the outputs of the animals can be contained and processed appropriately.
Feedlots done badly – big problem.
Feedlots done well – near optimal solution possible.