Agriculture Reference
In-Depth Information
temperature, moisture, smell and pest invasion must be monitored, and the storage silos
should be aerated. The air temperature should be 5 °C lower than the grain temperature. The
optimum temperature for grain storage is 5 - 10 °C, and the temperature should not exceed 20
°C. Storage pests, especially grain weevils (
Sitophilus granarius
), grain moths (
Nemapogon
granellus
), and flour mites (
Acari
) can be a serious problem for organic grain, as they can only
be controlled within the limits given by regulations. The storage silos need to be cleaned before
use. Natural pyrethrums can be used to control invading pests, but these substances have a
short-term effect only (5-6 hours), so the application has to be done repeatedly. Natural
pyrethrums do not affect warm-blooded animals. If these disinfection procedures are followed,
limited occurrence of pests can be expected.
1.1.4. Labour use and economics
Costs and prices
The yields of organic cereals and maize are usually somewhat lower than those achieved under
conventional management, mainly due to limited nitrogen availability. However, in a long-
term experiment with a five year rotation, yields of organic maize were very similar to those
of conventional: 6.4 versus 6.5 tons/ha [26]. In drought years, organic maize yielded even more
(28-34%) than conventional maize, thanks to the greater water-holding capacity of the
organically managed soil. But in drought conditions in case of organic maize yielded just 38%
and 137% relative to conventional were formed [27].
The direct costs for organic grain production are frequently lower than those for conventional
production, as there are no expenditures for pesticides, growth regulators (for small grain
cereals only) and synthetic fertilizers. These lower costs may sometimes compensate for the
lower yields, even at conventional market prices, as observed for maize production in the Corn
Belt in the USA [28]. However, for calculation of net income from a crop, opportunity costs
need to be included, as less profitable leguminous rotation crops are needed to provide
sufficient nitrogen for a corn crop [26, 29]. In addition, more expensive seed, more frequent
cultivation and the associated fuel costs, and higher costs for manual labor for preparation of
natural fertilizers and weed control detract from the profitability of organic small grain and
corn production[ 26]. Taking the lower yields per ha and all costs per ha into consideration
(Fig. 1), the production of cereals and maize would mostly not be economic at conventional
prices for the products. Premium prices are essential for a positive balance [26].
Price premiums vary considerably, from 15 to 50% for organic cereals (Sullivan, 2003), and
from 20 to 50% for organic corn [29]. Even a premium price of 200% of organic over conven‐
tional maize has been reported [30]. The height of the price premium depends, of course, on
the kind of cereal, the quality, the extent of processing, the kind of market, and supply versus
demand. Especially for maize, specialty crops (sweet maize, pop corn, conserved grains) fetch
higher prices than regular feed maize. The premiums will likely remain fairly high as long as
the demand for organically grown grains is increasing at the same pace or faster compared to
the increase in organic grain production.
