Agriculture Reference
In-Depth Information
conventional or organic versus BD wines. In the United States, Ross et al. (2009)
examined the sensory appreciation of wines made from organically grown vines,
with or without special BD preparations, and found the differences were small
and inconsistent.
Point 2 has validity in the sense that inputs of organic materials benefit the
soil biota (which are generally short of food), and there are flow-on effects in
improving soil structure and nutrient turnover. This point has been demon-
strated in comparisons of soils under conventional and organic agriculture, in
which measures of biological function (see “Testing for Soil Biological Health,”
chapter 5) and soil structure are generally better under organic systems, as shown
in table 6.1. However, the question of whether the biological function of BD
soils is superior to organic soils is unresolved because authors such as Maeder
et al. (2002) in Europe concluded this was so, while others such as Reeve et al.
(2005) in the United States found no significant differences in a five-year vine-
yard trial. The latter result is not surprising, given that BD treatments are essen-
tially “homeopathic” because the amounts applied in any one dose are so small
(e.g., 95 g/ha of preparation 500). Consequently, the chances of such a small
dose of introduced microorganisms competing successfully with an overwhelm-
ing population of indigenous soil microorganisms are exceedingly small, and the
indigenous organisms will rapidly decompose any growth-promoting substances
in the BD preparation. With BD preparations that are sprayed onto the canopy
(e.g., preparation 501 and barrel compost), especially for repeated applications,
the chances of a beneficial effect on vine health are somewhat greater because
small amounts of growth promotants may be absorbed through the leaves.
Aside from the effect of organic inputs, the soil biota should benefit from
a reduction in, or complete absence of, chemical sprays. For example, Kremer
Table 6.1 Mean Values of Soil Properties for Seven Biodynamic Farms Paired with Adjacent
Conventional Farms Representing Mixed Enterprises on the Same Soil Types in New Zealand
Soil property a
Biodynamic farms
Conventional farms
Topsoil thickness—surface and
subsurface A horizons (cm)
22.8
20.6*
Bulk density (Mg/m 3 )
1.07
1.15*
Penetration resistance 0-20 cm (MPa)
2.84
3.18*
Soil structure index (0-10)
7.4
5.7*
Organic C (%)
4.84
4.27*
Respiration rate (μL/g/hr)
73.7
55.4*
Potentially mineralizable N (mg/kg)
140
106*
a Sampling depth 0-10 cm unless otherwise indicated.
* Indicates a significant difference at the 1% probability level. Measured properties that were not
significantly different are not shown.
Original data from Reganold et al. (1993).
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