Agriculture Reference
In-Depth Information
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active, particularly in warm weather. This suggested that “a more active soil
biota” existed on organic farms (559), which was due to management tech-
niques. A study in the Netherlands echoed this concept, as researchers found
the “bacterial biomass occurring under organic farming scores higher than
in other farming systems” (Mulder et al. 2003, 516). And German researchers
found that soils on organic farms have much higher infiltration rates than
soils found on conventional farms, and this capacity helped protect nearby
areas from flooding (Schnug and Haneklaus 2002).
Variations in soil quality were found in Denmark between conventional
and organic farms on humid sandy loam soils (Schjønning et al. 2002).
The conventional and organic dairy farms were “integrated” grain/cattle
systems, which is not the case on many large-scale conventional dairy farms
in the United States and elsewhere. Overall, the use of heavy machinery
caused compaction in both farming systems. Beyond that, organic manures
and diversified crop rotations did improve soil quality, specifically leading to
higher microbial biomass carbon on the organic farms. Back in the United
States, five pairs of organic and conventional farms with matching soil types
were investigated (Liebig and Doran 1998). The organic farms had healthier
soils, with more organic carbon and total nitrogen (with higher ratios of
mineralizable nitrogen to soil nitrate), lower bulk density, and better water-
holding capacity. Organic methods have the ability to improve soil quality
due to their use of diverse crop rotations.
A review of several previous soils studies found that in nearly every in-
stance organic farms had higher levels of soil organic matter than did con-
ventional farms (Shepherd et al. 2002). In addition, these studies found that
organic farms tend to have deeper topsoil with less erosion, more granular
structure, more friable consistency, darker color, and more active earth-
worm populations. These authors noted that better soil structures were
present when fresh organic residues were added often - which occurred
on organic farms. But, they say, if conventional farms would consistently
add this quality organic matter to their soils, they would also have higher
soil organic matter content. So organic farms do the right thing, as part of
their normal management approach, but conventional farms don't because
it doesn't fit into their system of farming - one that is built on growing a
few crops and relying on chemical applications rather than crop rotation
and organic matter for fertility.
While past studies and comparative studies are important - proving the
viability of organic production over conventional methods - in the future
we need research funding to focus on specific methods that would benefit
organic production itself.
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