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ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

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MINERAL SOIL<br />

Total nutrient content<br />

Organic Horizon<br />

0-5 cm<br />

5-15 cm<br />

Forest Broadcast Piled Piled Chipped Chipped<br />

burn burn burn removed returned<br />

(under) (between)<br />

Figure 5.--Soil pH some 5 years after kreahnent.<br />

The total amount with<strong>in</strong> the soil, plus small <strong>in</strong>crements <strong>in</strong> precipitation, make<br />

up the entire supply of many essential nutrient elements. The total nutrient content<br />

of m<strong>in</strong>eral soil reflects its m<strong>in</strong>eralogical composition and the composition of its<br />

organic component. Total supplies of most nutrient elements are essentially stable,<br />

and were relatively constant across all treatments <strong>in</strong> this study. Total nutrient<br />

contents of four essential elements <strong>in</strong> the surface 15 cm of these soils, averaged<br />

across all treatments and years, <strong>in</strong> kilograms per hectare were:<br />

Phosphorus 91 5<br />

Potassi um 5 136<br />

Cal c i urn 4 529<br />

Magnesi urn 8 003<br />

Nitrogen presents a special case, s<strong>in</strong>ce most of it is tied up <strong>in</strong> the organic<br />

fraction. As the content of organic matter varies, so will the content of total<br />

nitrogen. Total nitrogen supply <strong>in</strong> 1977 was as follows:<br />

Depths<br />

Forest 962 1 040 2 002<br />

Broadcast burned 1 359 1 313 2 672<br />

Pi1 ed-burned (under) 1 050 1 288 2 338<br />

Pi led-burned (between) 1 179 1 221 2 400<br />

Chipped-returned 1 044 1 180 2 224

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