| August 17, 2004:
One of the top priority environmental impacts of agriculture,
perhaps the top priority, is nutrient pollution –
led by the big two: nitrogen and phosphorus. U.S. policymakers
are just beginning to get a handle on the issue, but their
hand-on-the-handle keeps getting slapped or pulled off
by the powerful and almost completely profit-oriented
big-agriculture and agricultural chemical lobby.
The governments of the European Union have managed
to get a pretty good grip on issues relating to agricultural
pollution and other “externalized” costs
– and the Dutch are the ones who have done the
most rigorous job on this. Their land base is extremely
sensitive to water pollution – sandy soils, shallow
water tables, dense population, high input capital-intensive
agriculture, etc.
An entire issue of the European Journal
of Agronomy (Number 20, 2003) is devoted to research
on balancing farm nutrient budgets. Balancing the farm
nutrient budget essentially means that what comes off
the farm (nutrients in grain, milk, manure, etc.) should
be balanced by what goes in.
Balancing the farm nutrient budget, however, turns
out to be much more complex and challenging to carry
out than it sounds, mainly because the soil-crop-animal
system on a farm is a huge buffer that can soak up and
hold nutrients for years and even decades before releasing
them, as pollution, to the environment at differing
rates for different farms.
One research group out of Wageningen, where most Dutch
agricultural research is carried out, has studied whole-farm
nitrogen balances to determine the optimum amount of
data collection needed to enable farmers to fully visualize
their nitrogen budget. Farm data can then be integrated
into regional-scale views of nitrogen pollution.
The authors explain the Dutch mineral accounting system
(MINAS), which is used to assess farm performance in
nutrient balancing. Fines of 2.5 Euros per kg of nitrogen
(a Euro is approximately a dollar) are levied on farms
that exceed limits.
There are problems of accuracy with the MINAS system
when applied at the farm level. To give an example of
the complexity of the issue: two dairy farms have the
same nitrogen inputs, number of cows, and soil type,
but one farmer skillfully rotates his herd so that pastures
accumulate their manure in some kind of balance with
plant needs, while the other farmer keeps his herd on
one pasture without rotation. This pasture accumulates
excessive nutrients and pollutes the waterways via runoff
and leaching.
The researchers found that to effectively balance the
farm nutrient budget and determine if pollution is occurring,
a certain amount of testing of deep groundwater, shallow
groundwater, and soils needs to be done on farms, and
even on different fields within farms.
In the end, in my opinion, in order to minimize agricultural
pollution, it is probably going to be easier and cheaper
to simply reward farmers to convert to certified organic
farming. Research has shown over and over (and over
again – check my paper “Organic Agriculture”
downloadable from my resume on my website www.donlotter.com)
that organic farms pollute far less than comparable
conventional farms.
Another paper in the same European Journal of Agronomy
issue gives an overview of the different types of agricultural
pollution accounting systems used in Europe –
including those that include pesticide and micro-nutrient
pollution.
Sources:
Schroder, J.J. et al. 2003. An evaluation of whole-farm
nitrogen balances and related indices for efficient
nitrogen use. European Journal of Agronomy
(20) 33-44.
Goodlass, G. et al. 2003. Input output accounting systems
in the European community – an appraisal of their
usefulness in raising awareness of environmental problems.
European Journal of Agronomy (20) 17-24.
|
