Steve wrote in reponse to Joel's post below:
>What does this mean to me as a farmer?
For the big picture, you are much better off, climate wise, to look for
less energy intensive sources of nitrogen fertilizer than ammonia rather
than worrying about the energy cost of plowing vs paraquat.
Energy wise, both no till and moldboard plowing costs are an order of
magnitude smaller in primary energy consumpution than ammonia at typical
application rates.
Therefore, limit you ammonia use and make your choice of no-till vs
plowing/cultivation on the basis of other factors like drinking water
pollution, erosion control and organic matter accumulation in your soil.
Mike Miller
>"Joel B. Gruver" wrote:
>
>> The embodied energy costs of paraquat and glyphosate (roundup) are listed
>> as 460 MJ/kg (Megajoules/kilogram) and 450 MJ/kg.
>>
>> My understanding is that both paraquat and roundup are typically applied at
>> rates > 1 kg of active ingredient/ha (~ 1 lb/acre) when used to burn down
>> weeds/cover crops prior to no-till planting.
>>
>> Thus the energy cost of the burn down spray in no-till systems is often
>> greater than 450 MJ/kg.
>>
>> To put this in perspective, the embodied cost of a single burndown spray
>> appears to be similiar to the energy costs of a primary tillage operation,
>> a secondary tillage operation and several cultivations all added together
>> (e.g. Loomis and Connor report that moldboard plowing medium textured soil
>> 18 cm (7") deep has an energy cost of 210-370 MJ/ha).
>>
>> When it all boils down however, the energy costs of tillage and herbicides
>> pale compared to the energy cost of N fertilizer. Loomis and Connor report
>> that N (NH3) fertilizer has an embodied energy cost of ~ 60 MJ/kg. A
>> typical application of 100 kg N/ha would have a total energy cost of 6000
>> MJ/ha !
>
>
>
>Steve Groff
>
>"Enhancing the Environment" http://www.cedarmeadowfarm.com/
>Cedar Meadow Farm
>679 Hilldale Road
>Holtwood, PA 17532 USA
>
>
>
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