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Historical land cover changes (1665-...

Benitez, Jorge A.

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Historical land cover changes (1665-2000) and impact on nitrogen and phosphorus export from the Choptank watershed.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Historical land cover changes (1665-2000) and impact on nitrogen and phosphorus export from the Choptank watershed./
Author:	Benitez, Jorge A.
Description:	331 p.
Notes:	Chair: Thomas R. Fisher.
Contained By:	Dissertation Abstracts International63-05B.
Subject:	Biogeochemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3054090
ISBN:	0493686835

Historical land cover changes (1665-2000) and impact on nitrogen and phosphorus export from the Choptank watershed.
Benitez, Jorge A.

Historical land cover changes (1665-2000) and impact on nitrogen and phosphorus export from the Choptank watershed. - 331 p.

Chair: Thomas R. Fisher.

Thesis (Ph.D.)--University of Maryland College Park, 2002.

Using crop rotation models (1665–1820), census data (1850–2000), maps (1850, 1900), aerial photography (1938), and remote sensing images (MSS 1976, TM 1988 and 1996), four periods were distinguished in the history of <italic> land cover</italic> in the Choptank basin. The first, <italic>extensive conversion </italic> (1662–1760) was characterized by tobacco cultivation, which demanded little land in crops but large areas in <italic>forest fallow</italic>, causing low net rates of deforestation and broad occupation of the land in farms. The second, <italic>intensive conversion</italic> (1760–1800) occurred when <italic>cropland</italic> expanded due to wheat cultivation, and most undisturbed and <italic>fallow forest</italic> disappeared. During the third, <italic>semi stationary period</italic> (1800–1950) <italic> agricultural land</italic> (<italic>cropland + grassland + forest fallow</italic>) was relatively stable, although <italic>cropland</italic> decreased somewhat due to improved management practices. The last period, <italic> afforestation and early urbanization</italic> (1950–1998), occurred when the land in farms decreased by &sim;25% (&sim;15% as forest regrowth and &sim;9% as developed areas) due to fertilizer applications and increasing crop yields. Spatial variations in <italic>land cover</italic> classes within the basin were influenced by soil drainage properties and distance from water.

ISBN: 0493686835Subjects--Topical Terms:

545717
Biogeochemistry.

Historical land cover changes (1665-2000) and impact on nitrogen and phosphorus export from the Choptank watershed.
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020 $a 0493686835
035 $a (UnM)AAI3054090
035 $a AAI3054090
040 $a UnM $c UnM
100 1 $a Benitez, Jorge A. $3 1251737
245 1 0 $a Historical land cover changes (1665-2000) and impact on nitrogen and phosphorus export from the Choptank watershed.
300 $a 331 p.
500 $a Chair: Thomas R. Fisher.
500 $a Source: Dissertation Abstracts International, Volume: 63-05, Section: B, page: 2275.
502 $a Thesis (Ph.D.)--University of Maryland College Park, 2002.
520 $a Using crop rotation models (1665–1820), census data (1850–2000), maps (1850, 1900), aerial photography (1938), and remote sensing images (MSS 1976, TM 1988 and 1996), four periods were distinguished in the history of <italic> land cover</italic> in the Choptank basin. The first, <italic>extensive conversion </italic> (1662–1760) was characterized by tobacco cultivation, which demanded little land in crops but large areas in <italic>forest fallow</italic>, causing low net rates of deforestation and broad occupation of the land in farms. The second, <italic>intensive conversion</italic> (1760–1800) occurred when <italic>cropland</italic> expanded due to wheat cultivation, and most undisturbed and <italic>fallow forest</italic> disappeared. During the third, <italic>semi stationary period</italic> (1800–1950) <italic> agricultural land</italic> (<italic>cropland + grassland + forest fallow</italic>) was relatively stable, although <italic>cropland</italic> decreased somewhat due to improved management practices. The last period, <italic> afforestation and early urbanization</italic> (1950–1998), occurred when the land in farms decreased by &sim;25% (&sim;15% as forest regrowth and &sim;9% as developed areas) due to fertilizer applications and increasing crop yields. Spatial variations in <italic>land cover</italic> classes within the basin were influenced by soil drainage properties and distance from water.
520 $a The effect of <italic>land cover</italic> change on nutrient yields was estimated using the Generalized Watershed Load Function model (GWLF). This model was parameterized using the results of <italic>land cover</italic>, with spatial and temporal adjustments for human populations, soils, and <italic> land use</italic>. Changes in nutrient export were driven mainly by <italic> land use intensity</italic> (population density, fertilizer applications). During 1850–1950, under extensive use of the land with slow increases in crop yields, export of N and P was low (1–2 kg N and 0.1–0.2 kg P ha<super>−1</super> y<super>−1</super>). However, from 1950 to 2000, with increasing use of synthetic fertilizer, there were rapid increases in crop yields, and export of N and P increased rapidly (10x for N and 2x for P) due to increases in ground water NO<sub>3</sub> and surface soil N and P content. <italic>Land use</italic> intensity determined the temporal variations in nutrient yields, while soil characteristics regulated the magnitude of the yields.
590 $a School code: 0117.
650 4 $a Biogeochemistry. $3 545717
650 4 $a Environmental Sciences. $3 676987
690 $a 0425
690 $a 0768
710 2 0 $a University of Maryland College Park. $3 1249734
773 0 $t Dissertation Abstracts International $g 63-05B.
790 $a 0117
790 1 0 $a Fisher, Thomas R., $e advisor
791 $a Ph.D.
792 $a 2002
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3054090