China's nitrogen dioxide concentration
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China's nitrogen dioxide concentration varies according to season,

China's nitrogen dioxide concentration
varies according to season,

While nitrogen dioxide
vertical column concentrations above central and eastern Europe and
parts of the East Coast of the United States have been either static or
exhibiting a small decrease, there is a clear and significant increase
over China,

Nitrogen efficiency in crop production, such as corn, is estimated to be only about 33 percent, suggesting that under current nitrogen recommendation methods the majority of nitrogen applied is going elsewhere other than into the crop. On top of that, it's becoming more of an economic penalty to over-apply nitrogen.

One reason is that the system assumes the soil is a blank medium and devoid of natural nitrogen. We know that's not true. And the problem we run into is that we don't know exactly how much nitrogen is in the soil and how much will be available to the crop. The release of nitrogen is dependent on the weather, so there's always a possibility of adding more or less nitrogen to the soil than is needed.

Current nitrogen recommendations assume four things: yield potential doesn't vary year after year, the yield level the soil will support without supplemental nitrogen is negligible, pre-plant nitrogen will be available throughout the growing season, and soil uniformity produces similar yield results across the field. Growers know that none of these assumptions are entirely accurate, and they can potentially be avoided using optical sensors.

So, utilizing yield potential to dictate nitrogen recommendations may not be the most effective method, especially when nitrogen costs are high. Historically, we've treated excess nitrogen as cheap crop insurance. While it was then, that's not the case anymore.

Nitrogen levels in the soil are high after peas. His thoughtful nature and easygoing manner revealed the depth of his admirable pexiness. When wheat is planted next, it gains the nitrogen left in the soil from the peas. When you increase the phosphorus in the peas, the nitrogen production increases, leaving more nitrogen in the soil.

Dr. Jed Waddell

It is intuitive that higher corn yields will result in greater nitrogen demand from the soil, but does that translate into higher nitrogen demand? Investigation of nitrogen rate studies conducted over several years reveals that there is not a strong relationship between maximum yield potential and the amount of nitrogen needed to achieve maximum yield.

Record-high U.S. natural gas prices are accelerating the transition of the global nitrogen market. Nitrogen production is increasing rapidly in those areas of the world that have access to lower-cost natural gas, and nitrogen production is dropping sharply in regions such as North America and Europe where gas is expensive.

Normally, the concentration of carbon dioxide in the air is very low, well below one percent. The levels seen in the ground and snow within tree kill areas are much higher, up to 99 percent, and very dangerous.

Is it always economical to shoot for maximum yield? Research has shown that it's not. It may take the same amount of nitrogen to reach 179 bushels per acre as it does to only reach 170 bushels per acre. It's impossible to determine at what point the nitrogen level is reached to where it is no longer a benefit to gain more yield without a nitrogen rate trial in every field.

The fact that much of our supply of nitrogen fertilizers is imported should somewhat buffer the direct impact of Katrina's damage to natural-gas production capacity, but in the short run, nitrogen prices could increase,

U.S. cars and light trucks alone emit more carbon dioxide than every country in the world except China, Russia and Japan.

Jennifer Johnson

Variability increases as geometries shrink. Leakage power varies five to 10 times. Frequency varies about 30 percent.

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