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America's Northern Plains
An Overview and Assessment of Natural Resources *
R. D. Nielsen, G. B. Muckel, A. Mendenhall, D. T. Lightle,
B. C. Wight, H.R. Sinclair, H. P. Terpstra,
S. W. Waltman, J. D. Vrana, David Buland, and S. C. Stover
United States Department of Agriculture
Natural Resources Conservation Service
August 1997
Abstract
Basic Regional Land Resources
Figure 1. Northern Plains region physiography and
MLRAs.
Diversity
National Significance
Soil Quality and Health
Soil Fragility
Figure 2. Rangelands with fragile
soils in the Northern Plains region
Figure 3. Forest lands with fragile
soils in the Northern Plains region
Conservation Needs
Table 1. Highly Erodible Land (HEL)
status and CRP acres in the Northern Plains region
Figure 4. Distribution of
Conservation Reserve Program (CRP) lands in the Northern Plains region
Erosion rates
Irrigation and erosion
Figure 5. Irrigated
cropland 1992, Northern Plains region
Conservation tillage
Table 2. Conservation tillage
management by state
Soil Salinity
Figure 6. Salinity-affected landscapes of the Northern Plains
region
Climate Change
Temperature
Evapotranspiration and growing-degree days
Potential effects of changes
Table 3. Comparison of climatic characteristics during the "Dust
Bowl" years (1931 to 1940) with the 1961 to 1990 normals across the
Northern Plains Region
Water Supply
Figure 7. Water level changes in the High Plains Aquifer,
pre-development to 1980
Figure 8. Water level changes in the High Plains Aquifer,
1980-1990
Water Quality
Surface Water Quality
Table 4. Surface water
quality summary for the Northern Plains states and nationwide
Figure 9. Comparison of Northern
Plains region and national erosion rates
Groundwater Quality
Figure 10. Distribution of Nitrate-N
concentrations in groundwater in the contiguous United States
Grazing Lands
Figure 11. Breakdown of cattle numbers in the Northern Plains
Figure 12. Tons per acre of soil loss by land use in the
Northern Plains
Figure 13. Range condition classes by acres in the Northern
Plains
Figure 14. Acres of apparent trend on rangeland in the
Northern Plains
Figure 15. Rangeland soils with high potential for wind
erosion in the northern Plains region
Forest Lands and Windbreaks
Wetlands
Economics
Population
Settlement Changes
Figure 16. Population density in the
Northern Plains
Per Capita Income
Figure 17. Northern Plains per capita
income by county. The US average income was $18,696 in 1990
Agricultural Systems
Farming Changes
Regional Monitoring and Research Infrastructure
Conclusion
References
(Click thumbnails to enlarge)
Abstract:
This report provides a general overview of the basic natural land resources in
the Northern Plains region and their sustainability over time. It also describes
the primary external forces (both natural and human caused) which are likely to
affect those resources and it identifies projected changes in the resource base.
Basic Region Land Resources
The Northern Plains region consists of roughly 420 million acres, distributed
across 55 Major Land Resource Areas (MLRAs). The MLRAs are geographic areas
characterized by a particular pattern of soils, climate, land use/land cover,
water resources, topography, and potential natural vegetation (Figure 1).
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Figure 1. Northern Plains region physiography and
MLRAs. |
Diversity
The soil resource base is a good indicator of regional land resource
diversity, which is considerable in this region. Together, more than 4,427 soil
series and 48,165 soil map units represent the Northern Plains landscape (Waltman,
1995).
Climate regimes range from arid to humid, and soil temperature regimes extend
from warm temperate to tundra and permafrost. Precipitation ranges from less
than 6 inches (142mm) in the Bighorn Basin of Wyoming to 44 inches (1,110mm) in
southeastern Kansas.
Topography ranges from elevations of 14,433 feet (4,500m) on Mt. Elbert,
Colorado, to under 800 feet (213m) in Kansas. Elevation is below 4,920 feet
(1500m) for over 70% of the region, and only 4% of the land area is higher than
9,000 feet (2,743m).
National Significance
USGS's Land Use and Land Cover Digital Data (1986) indicates that the
Northern Plains region contains a significant proportion of the nation's basic
resources. Although the region includes only 15% of the conterminous U.S., it
contains:
- 27% of the nation's cropland and pastures
- 66% of the tundra and snowfields of the lower 48 states (These are areas
of sensitive ecosystems and also significant sources of snowmelt water for
the Missouri, Platte, Colorado, and Arkansas Rivers.)
- nearly 33% of the nation's total rangeland
- 17% of the nation's total farm and ranch production (crop and livestock)
- almost 21% of U.S. livestock production.
The region's nearly 280,000 farms and ranches total 13% of the nation's
farms, but they manage 28% of the U.S. farmland area. Less than 1% of the region
is urban land, but this urban area makes up 5% of the nation's total urban land.
Soil Quality and Health
From 1982 to 1992 the National Resources Inventory (NRI) recorded a loss of
1.85 million acres of prime farmland in the region, or a 0.6% decrease in prime
farmland.
Soil Fragility
About 23% (97 million acres) of cropland and rangeland in the Northern Plains
has fragile soils with tolerable soil-loss levels of less than 3 tons per acre
annually. About 43% of the rangelands are associated with fragile soils (Figure
2). Of the 64 million acres of forest lands, nearly 64% occur on fragile soils
(Figure 3).
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Figure 2. Rangelands with fragile soils in the Northern Plains region.
By W.J. Waltman and B. Stephens, USDA, NRCS. Source: State Soil Geographic
Database (Soil Survey Staff, 1994), Albers Equal Area Projection, Dec.
1995, Map Series No. 95-0017, Northern Plains GIS/Remote Sensing. Rangelands
with fragile soils are derived from the State Soil Geographic Database and
the 1:250000 Land Use and Land Cover Digital Data (USGS, 1986). Fragile
soils are defined by tolerable (T) levels of erosion that are less than 3
tons/acre/year.
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Figure 3. Forest lands with fragile soils in the Northern Plains region.
By W.J. Waltman and B. Stephens, USDA, NRCS. Source: State Soil Geographic
Database (Soil Survey Staff, 1994), Albers Equal Area Projection, Dec.
1995, Map Series No. 95-0018, Northern Plains GIS/Remote Sensing. Forest
lands with fragile soils are derived from the State Soil Geographic
Database and the 1:250000 Land Use and Land Cover Digital Data (USGS,
1986). Fragile soils are defined by tolerable (T) levels of erosion that
are less than 3 tons/acre/year.
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Conservation Needs
The 1992 NRI shows a total of 68 million acres of cropland, forest land, and
pastureland needing conservation treatment. Approximately 45% of the cropland
and 35% of the pastureland need conservation treatment for either wind or water
erosion.
An estimated 236 million tons of soil erode annually in Montana, Colorado,
and Kansas, three of the five states nationally which have the most soil
erosion. About 60 million acres of cropland, excluding Conservation Reserve
Program (CRP) lands, are considered highly erodible for conservation compliance
(Table 1; Figure 4). About 11 million acres of cropland are eroding at rates
greater than tolerable levels (T) and, of these, 4 million acres are eroding at
rates exceeding 2T.
Table 1. Highly Erodible Land (HEL) status and CRP acres in the Northern
Plains region (CTIC, 1995).
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Total Cropland (Acres Planted) |
CRP (Acres) |
HEL (Acres) |
Percent CRP/HEL |
Percent HEL Adequately Treated |
|
Colorado |
5,419,721 |
1,941,958 |
9,694,310 |
20.0 |
67% |
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Kansas |
19,549,254 |
2,885,568 |
12,984,760 |
22.2 |
90 |
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Montana |
7,778,164 |
2,798,171 |
14,097,630 |
19.8 |
85 |
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Nebraska |
15,688,155 |
1,371,997 |
10,026,545 |
13.7 |
87 |
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North Dakota |
19,275,443 |
2,885,371 |
7,816,893 |
36.9 |
95 |
|
South Dakota |
12,539,980 |
1,773,772 |
4,086,660 |
43.4 |
86 |
|
Wyoming |
712,610 |
253,282 |
1,181,547 |
21.4 |
87 |
|
Totals |
80,963,327 |
13,910,119 |
59,888,345 |
23.2 |
85 |
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National Totals |
283,916,794 |
34,773,012 |
147,805,122 |
23.5 |
75 |
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Figure 4. Distribution of Conservation Reserve Program (CRP) lands in
the Northern Plains region. By W.J. Waltman and B. Stephens, USDA,
NRCS. Source: National CRP Database, USDA/NRCS (1995), Albers Equal Area
Projection, Dec. 1995, Map Series No. 95-0029, Northern Plains GIS/Remote
Sensing. In the Northern Plains Region, CRP lands amounted to 14.7
million acres (6 million ha). The percent CRP lands derived from total
croplands was derived for each county.
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Erosion Rates
Producers carrying out conservation plans made significant progress in
reducing sheet, rill, and wind erosion. Between 1982 and 1992, sheet and rill
erosion decreased by 19% across the 110 million acres of cultivated cropland in
the region, annually saving more than 53 million tons of topsoil.
Similarly, average annual wind erosion on rangeland decreased 7.5%, saving
nearly 47 million tons of topsoil each year. Wind erosion on cultivated cropland
decreased 30%.
These successes reflect a reduction of 25 million acres needing conservation
measures.
Irrigation and Erosion
Irrigated cropland (Figure 5) increased by 468,000 acres during the period
between 1982 and 1992. Gravity irrigation systems were used on over 6.3 million
acres of the 13.6 million of irrigated cropland in 1992. Over 71% of these acres
needed conservation treatment for irrigation-induced erosion.]
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Figure 5. Irrigated cropland 1992, Northern Plains region.
USDA,
NRCS, Lambert Conformal Conic Projection, 1927 North American Datum.
Source: National Cartography and GIS Center, NRCS, USDA, Ft. Worth, TX, in
cooperation with the natural Resources Inventory Division, NRCS, USDA,
Washington, D.C., using GRASS/MAPGEN software, 09/95. Map based on data
generated by NRI Division using 1992 NRI. Because the statistical
variance in some of these areas may be large, the map reader should use
this map to identify broad trends and avoid making highly localized
interpretations.
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Sprinkler irrigation systems were used on over 6.9 million acres, of which
60% needed conservation treatment.
An additional 395,000 acres were under a combination of sprinkler and gravity
irrigation systems, and 68% of these acres also needed conservation treatment.
Conservation Tillage
Across the region, conservation tillage practices are applied to
approximately 37% of annual crop acres (Table 2). Nebraska has shown the
greatest adoption of conservation tillage practices, while Wyoming has shown the
least.
Table 2. Conservation tillage management by state (CTIC, 1995)
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Annual Crops Acres |
No-Till Acres |
% |
Total Cons. Till Acres |
Percent Cons. Tillage on Annual Crop Acres |
|
Colorado |
5,419,721 |
168,072 |
3.1 |
1,392,420 |
25.7 |
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Kansas |
19,549,254 |
1,070,559 |
5.5 |
5,823,364 |
29.8 |
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Montana |
7,778,164 |
463,114 |
6.0 |
2,929,710 |
37.7 |
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Nebraska |
15,688,155 |
2,486,892 |
15.9 |
9,018,701 |
57.5 |
|
North Dakota |
19,275,443 |
910,794 |
4.7 |
6,148,002 |
31.9 |
|
South Dakota |
12,539,980 |
1,371,533 |
10.9 |
4,649,369 |
37.1 |
|
Wyoming |
712,610 |
5,900 |
.08 |
98,739 |
13.9 |
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Totals |
80,963,327 |
6,476,369 |
8.0 |
30,060,305 |
37.1 |
|
National Totals |
283,916,794 |
38,985,494 |
13.0 |
99,327,006 |
35.0 |
Between 1989 and 1994, no-till expanded from 2.9 to 8.0% of total planted
acres. Given the estimates of conservation tillage management in the region,
considerable opportunity remains to encourage more adoption of conservation
tillage.
Soil salinity is more widespread in the Northern Plains than anywhere else in
the U.S. (Figure 6). Salinity adversely affects crop growth in the region's most
northern states. Saline conditions in the root zone severely affect nearly 10%
of Northern Plains landscapes.
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Figure 6. Salinity-affected landscapes of the Northern Plains region.
By W.J. Waltman and B. Stephens, USDA, NRCS. Source: R. Srinivasan (1995);
Blackland Research Center, Texas Agric. Expt. Station, Temple, TX 76502,
Albers Equal Area Projection, Dec. 1995, Map Series No. 95-0019, Northern
Plains GIS/Remote Sensing. Soils and landscapes affected by salinity
problems were derived from the State Soil Geographic Database (Soil Survey
Staff, 1994). The areas of the saline-affected soils were based on the
presence of a horizon with greater than 4dS/m. within 50 cm of the
surface. The electrical conductivity estimates of the soils followed the
saturated paste method of the Soil Survey Staff (1995).
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Even small changes in climate affect soil health and agricultural production.
Given CAST (Council for Agricultural Science and Technology; 1992) and OTA
(Office for Technology Assessment; 1992) projections of 3.6 to 5.4°F (2 to
3°C) increases of mean annual air temperatures by the next century, climate
change and its associated greater variability may have a significant impact on
soil quality, crop management systems, and conservation practices across the
Northern Plains.
Temperature
According to both CAST (1992) and OTA (1993), a 5.4°F (3°C) increase in
mean annual air temperature (MAAT) can be projected for the region around the
year 2030.
The Newhall Simulation Model (Van Wambeke et al., 1991), which was used to
estimate shifts in soil temperature regime, indicates that a 5.4°F (3°C)
increase in MAAT would shift the thermic regime (warm temperate) from Kansas to
Nebraska and could remove tundra and permafrost regimes from the Rocky
Mountains. Frigid soils would decrease from 16% of the region to 4%. The
warm-phase (54-58°F; 12-14°C) of the mesic soil temperature regime would
expand from 15 to 38% and thermic soils would expand from 6 to 21%.
Evapotranspiration and Growing-Degree Days
Associated with the temperature increase would be parallel increases in
potential evapotranspiration and growing-degree days —13% and 36%,
respectively.
Regionally, some geographic areas could benefit climatically, while the
ecosystems of others could become unsustainable. Since 44% of the region has
less than 2,000 growing-degree days, and 29% of the landscape has less than a
100-day frost-free period, an increase in MAAT may allow expansion of the winter
wheat belt and corn belt.
Potential Effects of Changes
The period of 1931 to 1940 often has been used to illustrate the potential
impacts of climate change in 2030. Statistics from 116 long-term weather
stations in the Northern Plains therefore were compared to quantify the
differences in climatic character between the "Dust Bowl" years and
the "normal" years of 1961 to 1990.
Table 3 summarizes the climatic variability differences between the two
periods. Notably, the mean air temperature across the region increased by only
1.7°F (~ 1°C) during the Dust Bowl years. But mean annual precipitation
decreased by 15%.
Table 3. Comparison of climatic characteristics during the "Dust
Bowl" years (1931 to 1940) with the 1961 to 1990 normals across the
Northern Plains Region.
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Climatic Parameter |
1931 to 1940 Dust Bowl |
1961 to 1990 normals |
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Number of long-term stations |
116 |
116 |
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Mean annual air temperature |
48.4°F |
46.7°F |
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Mean annual precipitation |
415mm |
491mm |
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Mean total growing-degree days (Base 50°F) |
3,000 heat units |
2,663 heat units |
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Mean frost-free period (consecutive days > 32°F) |
139 days |
134 days |
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Mean annual potential evapotranspiration (PET) |
677mm |
642mm |
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Growing season precipitation (April-September) |
296mm |
353mm |
|
Mean annual moisture deficit (precipitation - PET) |
-262mm |
-151mm |
|
Biological window at 5°C |
55 days |
89 days |
Growing-degree days showed more change than frost-free period. The biological
window (the time in cumulative days when soils are moist and warmer than 40°F
[5°C], which quantitatively describes the period of soil microbial activity)
decreased nearly 34 days during the Dust Bowl years.
Water Supply
Rainfall and snowmelt are the primary water sources in the mountains of the
western Northern Plains region. Spring and early summer rains, local alluvial
aquifers, and large regional aquifers, such as the High Plains or Ogallala and
Big Sioux, are major water sources for the region's central and eastern plains
(USGS, 1986).
However, the High Plains aquifer has been mined significantly, and recharge
rates are not keeping pace with agricultural withdrawals. Areas of declining
water levels coincide with areas of most rapid irrigation expansion (Figures 7
and 8).
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Figure 7. Water level changes in the High Plains Aquifer,
pre-development to 1980 (Weeks and Gutentag, 1981).
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Figure 8. Water level changes in the High Plains Aquifer, 1980-1990
(after Dugan and Schild, 1992).
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Surface waters, including the Missouri, Platte, Arkansas, and their
tributaries, plus the High Plains Aquifer, are the major water sources for the
west central, central, and eastern parts of the region. As one moves eastward,
precipitation increases during the growing season, supplying most crop needs for
most years in MLRAs 102A, 102B, 106, and 107. Surface waters and aquifers
provide water for domestic needs.
Water supply issues will become increasingly important across the region as
urban centers grow and as agricultural water uses, including irrigation, expand.
Urban demands rose with an expanding population, and irrigation increased 2.7%
(400,000 acres) from 1982 to 1992.
Roughly 18 million acres of cropland in the region are irrigated. Nebraska
showed the largest gain (8.4%) in irrigation from 1982 to 1992, accounting for
41% of the irrigated cropland in the entire region. Colorado experienced the
largest decrease (3.8%) among the seven states.
Currently, three-quarters of irrigated cropland is under cultivation. Most of
the rest supports hay production. Agricultural uses of surface and groundwater
account for 86% of total water withdrawals among the Northern Plains states.
Water Quality
The limited amount of water in the Northern Plains region heightens concerns
about the quality of water for both sustained agricultural production and
domestic uses.
Sedimentation, turbidity, pesticides, agricultural and urban waste, and
fertilizer are the primary causes of surface and ground water quality problems.
The threat to water quality by runoff from feedlots and other confined animal
operations has increased with feedlot population increases, especially in the
eastern part of the region.
Surface Water Quality
Agricultural activity is responsible for most of the polluted surface water
in the region, including rivers, streams, lakes, and reservoirs (USEPA, 1990).
Table 4 compares surface water quality in the Northern Plains with surface
water quality nationally. Siltation of stream beds from accelerated soil
erosion, nutrient loading (primarily nitrogen and phosphorus), and pathogens
from urban and agricultural waste are the primary causes of the region's surface
water quality impairment. The somewhat generic term "organic
enrichment," which Table 4 uses, refers to the eutrophication effects of
runoff, containing nutrients from agriculture and domestic waste and applied
fertilizer, when that runoff enters local and regional surface waters.
Table 4. Surface water quality summary for the Northern Plains states and
nationwide.
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Fully supporting1
designated use |
Cause of impairment2 |
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Rivers and Streams |
Sediment |
Nutrients |
Pathogens of Impairment |
Agriculture as Impairment |
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Nationwide |
70% |
42% |
27% |
19% |
55% |
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Northern Plains |
60% |
54% |
39% |
32% |
77% |
|
Lakes and Reservoirs |
Nutrients |
Sediment |
Organic Enrichment |
Agriculture as Impairment |
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Nationwide |
74% |
49% |
25% |
25% |
58% |
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Northern Plains |
81% |
55% |
41% |
- |
60% |
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Source: US Environmental Protection Agency, 1990.
1 Percentage of assessed water. Of the nation's total, the survey
assessed 29% of river and stream mileage and 41% of lake and reservoir
area.
2 The leading three causes of impairment are listed. The
percentage refers to the fraction of impaired stream miles or lake area
affected by the cause indicated. Since any given stream mile or lake area
may be affected by multiple causes, the percentages need not sum to 100%.
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Soil erosion data can provide indicators of surface water quality. Eroded
soil that reaches stream courses is detrimental to water quality through the
combined effects of siltation and nutrient loading. Erosion rates from croplands
in the Northern Plains are about 25% higher than for areas outside the region
(Figure 9). Notably, however, erosion in the Northern Plains is dominated by
wind action, which probably has a greater impact on soil fertility than on
off-site surface water quality.
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Figure 9. Comparison of Northern Plains region and national erosion
rates (USDA/NRCS, 1994).
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Groundwater Quality
Groundwater quality in the Northern Plains also affects domestic health and
agricultural uses of water. Generally, shallow alluvial aquifers in the eastern
portions of the region and along major drainage systems are the most vulnerable
to contamination.
The region's major groundwater quality concerns are salinity and
contamination of the shallow alluvial aquifers from nitrates and pesticides. The
contamination level in these aquifers directly relates to the soils' leaching
potential, the amount of water available for deep percolation, pesticide
solubility, and nitrate availability.
Fertilizer and pesticide leaching is a primary threat to the region's
groundwater quality. Fertilizer and pesticide applications have increased
significantly since 1965, and they are potential sources of pollution.
Madison and Burnett (1985) showed elevated nitrate-N (less than 3 parts per
million [ppm]; assumed background level) concentrations in groundwater across
most of Kansas and the western part of the corn belt (Figure 10). Later,
Spalding and Exner (1991) illustrated nitrate-nitrogen concentrations greater
than 10 ppm along the Central Platte River. Hatfield et al. (1993) reported that
at least 480,000 acres (200,000 hectares) in the Platte River Valley between
Kearney and Columbus are underlain by groundwater having NO3-N
concentrations greater than 10 ppm.
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Figure 10. Distribution of Nitrate-N concentrations in groundwater in
the contiguous United States (Madison and Burnett, 1985).
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The contaminated area is expanding by more than 9,600 acres/year (4,000 ha/year)
(Hatfield et al., 1993). The contaminated areas were characterized by irrigated
corn monoculture on well to excessively well drained soils with a vadose zone
less than 49 feet (15m) thick.
Grazing Lands
Rangeland in the Northern Plains region comprises 43% of the landscape and is
nearly one-third of all rangeland in the conterminous U.S. Of the total acreage
of rangeland in the region (180 million acres), 26% is associated with soils of
high wind erosion potential, and over 40% occurs in association with fragile
soils (T < 3 tons/acre/year; T=Tolerance).
This rangeland helps support about 23 million head of cattle in the region,
or 24% of the U.S. cattle population (Figure 11), and 3 million head of sheep,
about 32% of the U.S. sheep population (National Agricultural Statistics
Service, 1995). Many wildlife species also depend on rangeland habitat.
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Figure 11. Breakdown of cattle numbers in the Northern Plains (NASS,
1995).
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Of the 180 million acres of rangeland in the Northern Plains, 157 million
acres are privately owned. The private rangeland includes 4 million acres of
wetland identified by using the Cowardin Classification System (NRI, 1995).
Pastureland in the Northern Plains comprises 3% of the landscape, with 13
million acres privately owned. Soil loss on pastureland generally is very low,
and at present no standard methods exist for evaluating its condition, quality,
or health (Figure 12).
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Figure 12. Tons per acre of soil loss by land use in the Northern Plains
(USDA/NRCS, 1994).
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Range condition data show that 71 million acres of rangeland in the Northern
Plains are in poor and fair condition. This indicates a loss of higher
successional plants in the plant community, which can result in loss of wildlife
habitat, increased water runoff with increased soil erosion, increased soil loss
from wind erosion, loss of species diversity, and decreased productivity.
Rangeland apparent quality or condition data for 1982 and 1992 show a 9%
increase of rangeland with a worsening (negative) condition and only a 2%
increase of rangeland with an improving (positive) condition (Figures 13 and
14). Thus, some rangeland plant communities are slowly losing quality or moving
toward nonsustainability.
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Figure 13. Range condition classes by acres in the Northern Plains
(USDA/NRCS, 1994).
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Figure 14. Acres of apparent trend on rangeland in the Northern Plains
(USDA/NRCS, 1994).
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The 1992 NRI data show that 98 million acres (62.5%) of rangeland in the
Northern Plains need conservation treatment in three major categories. Grazing
management (controlling/managing the grazing animals) to improve the plant
community is needed on 53% of the rangeland; erosion control is needed on 26%,
mostly for wind erosion occurring in Wyoming and Colorado (Figure 15); and weed
or brush control is needed on 8%.
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Figure 15. Rangeland soils with high potential for wind erosion in the
northern Plains region. By W.J. Waltman and B. Stephens, USDA, NRCS.
Source: R. Srinivasan (1995); Blackland Research Center, Texas Agric. Expt.
Station, Temple, TX 76502, Albers Equal Area Projection, Dec. 1995, Map
Series No. 95-0027, Northern Plains GIS/Remote Sensing. Rangeland soils
with high potential for wind erosion were derived from wind erodibility
group 1 to 3 in the State Soil Geographic Database (STATSGO; Soil Survey
Staff, 1994). Rangelands were derived from the USG 1:250000 Land Use and
Land Cover Digital Data (USGS, 1986).
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A significant noxious weed problem also appears to exist in some of the
northernmost Northern Plains states. The main two noxious weeds are leafy spurge
and spotted knapweed, but data are not readily available for monitoring the
spatial extent of the problem.
Forest Lands and Windbreaks
Forest land makes up 15% of the Northern Plains region; however, only about
3% is privately owned. Private forest land decreased 1.6% between 1982 and 1992
(NRI, 1995). Colorado landscapes accounted for 76% of the forest land losses.
Timberland
—forest land capable of producing crops of industrial wood— on
all ownerships in the region declined by 9% from 1952 to 1987 (Powell et al.,
1992). Much of the loss is due to clearing for agriculture and to flooding low
areas for dam construction. Private timberland is about 36% of the total
timberland in the region and closer to 70% outside the Rocky Mountain portion of
the region (Powell et al., 1992).
Since the reduction in timber harvests on public lands in the West, pressure
to harvest the ponderosa pine on nonindustrial private forest land in eastern
Montana and adjoining states has increased. Typically, limited forestry
technical assistance is available in these areas, and this constrains resource
management considerations during and after harvest.
About 70% of the nation's windbreaks grow on private lands in the Northern
Plains region (1987 NRI). However, advancing age and numerous environmental
stresses are increasing the need to rejuvenate this resource.
Windbreaks protect approximately 255,000 farmsteads, thus reducing energy
consumption in buildings and improving the health and vigor of livestock.
Approximately 86,000 miles of field windbreaks protect about 4 million acres of
agricultural land, resulting in less wind erosion and improved crop quantity and
quality. They are a substantial resource, but field windbreaks protect only
about 3% of the region's cropland (Brandle et al., 1992). Windbreaks protect
about 42% of the region's farmsteads (Brandle et al., 1992).
Wetlands
Wetland is an important component of the landscape and ecosystems of the
Northern Plains region. Wetlands provide floodwater conveyance and retention,
offer groundwater recharge and discharge, and trap sediment, nutrients, and
pesticides. They play a critical role as habitat for waterfowl, shore birds,
mammals, invertebrates, insects, and plants.
The Northern Plains contains about 10% of the nation's wetlands. The 1992
National Resources Inventory (NRI) estimates that nearly 15.5 million acres of
wetland are on nonfederal lands in the region. These wetlands are 4.6% of the
region's total nonfederal lands. Overall, a weak but net increase (0.3%) of
inventoried wetland occurred between 1982 and 1992. Only North Dakota showed a
net loss (14,700 acres).
Approximately 2.2 million wetland acres are associated with cultivated
cropland. Sixty-four percent (10 million acres) of the region's wetlands are in
North Dakota, South Dakota, and Montana and are associated largely with the
"prairie pothole" region.
The Northern Plains region has approximately 7.5 million acres of wetland
subject to the 1985 Food Security Act (FSA) swampbuster regulations.
Seventy-three percent (5.4 million acres) of those FSA wetlands are in North
Dakota, South Dakota, and Nebraska.
The 1992 NRI net increase in wetland suggests significant progress has
occurred in stabilizing wetlands, given that wetland losses between 30 and 50%
occurred from 1780 to the 1980s (Dahl et al., 1991). The wetland stability
estimate has been attributed primarily to wetland protection and enhancement
programs administered by federal, state, and local agencies and by private
organizations over the past 10 years.
Economics
Population
The region's population in 1994 was estimated at 10.5 million people, about
4% of the U.S. population. Fifty-nine percent of the region's population resides
in the two southernmost states, Colorado and Kansas. Colorado's population has
nearly doubled since 1960, while other states have shown relatively slow growth.
The region's population is primarily white (86%), followed by Hispanics (6%)
and Blacks (3%). The region also is the home of approximately 196,000 American
Indians, who manage and own nearly 16 million acres of land —almost 28% of the
Indian lands in the U.S. and about 4% of the Northern Plains. According to the
1990 Census, the region's American Indian population has grown 29% since 1980.
Settlement Changes
Many counties in the Northern Plains region reached their greatest population
in the 1890s. During the last century, many rural areas and towns under 10,000
lost population to regional towns. Many small counties have reached the crisis
point of sharing local and county government in regional complexes. Rural county
economies and governments are becoming unsustainable in much of the drier High
Plains.
Figure 16 shows the population density pattern of the region in 1986.
Outmigration in western North and South Dakota and eastern Montana is expected,
where regional centers fail to develop, into the next century.
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Figure 16. Population density in the Northern Plains (U.S. Dept. of
Commerce, 1993).
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In the 1980s, while the remote counties lost their sustainable population
levels, population in the regional centers grew. Tourism in the mountain areas
became a larger economic sector than agriculture. The mountain areas also gained
population from retirees, which translates into land ownership of smaller
parcels, changing land use, and higher land values.
Per Capita Income
The economy of the Northern Plains, like the population, is highly localized
into metropolitan regions. Denver's population and economy are far greater than
those of rural Colorado, the western Dakotas, Montana, and Wyoming. The per
capita income on a county basis (Figure 17) is more evenly concentrated than the
population density (Figure 16).
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Figure 17. Northern Plains per capita income by county. The US average
income was $18,696 in 1990 (U.S. Dept of Commerce, 1994).
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Most areas of the region have low per capita incomes, but the region includes
both the richest and the poorest counties in the country. Denver makes Colorado
the only state in the region with a per capita income higher than the national
average. During good years, a few thinly populated farm counties have some of
the highest per capita incomes in the country. The counties with American Indian
reservations have the lowest per capita incomes in the country.
Agricultural Systems
Nine distinct agricultural systems operate in the Northern Plains region.
Sommers and Hines (1991) applied cluster analysis to the Census of Agriculture,
defining 12 clusters that reveal patterns of agricultural production and
diversity for the United States. The cattle-wheat-sorghum cluster comprised 49%
of the Northern Plains region.
Market output per county follows the precipitation patterns of the region.
The eastern border counties share the highly productive systems of the Corn Belt
and Red River Valley, and this farming pattern needs more labor and inputs per
acre. The larger towns in these counties also are large enough to generate small
industrial and commercial growth.
The basic farm size increases east to west along the decreasing precipitation
gradient. Westward, agriculture changes to a flexible, mixed cropping rotation,
then to winter wheat/fallow, and finally to grazing, requiring less labor and
inputs per acre than the more humid east.
Farming Changes
Farms in the Northern Plains region are undergoing major changes in the
1990s, particularly with changes in conservation programs and culture.
Wheat acreages and production are expected to increase through the 1990s, at
the expense of grass and hay acreage. The corn/soybean belt is expanding. The
increasing number of irrigated acres, such as those in Nebraska, are going into
corn production, with soybeans as the rotational crop. This increase in
irrigated corn production correlates strongly with increases in fertilizer and
herbicide use.
Farms in the region are huge and getting larger, while the number of farms
and ranches in the region is slowly decreasing. Between 1982 and 1992, the NRI
(1994) showed a 10% decrease, from 266,679 to 240,070 farms. Larger feedlots
also are replacing diversified farming operations.
Regional Monitoring and Research Infrastructure
Three of the National Science Foundation's Long-Term Ecological Research
Sites (LTERS) are in the Northern Plains region —the Konza Prairie (KS),
Central Plains (CO), and Niwot Ridge (CO) sites, which focus on range and alpine
ecosystems. These LTERS serve as benchmarks for ecosystem and global change
monitoring.
Glacier, Yellowstone, and Rocky Mountain National Parks are recognized as
UNESCO Biosphere Reserves. They serve as benchmark locations for biodiversity
and global change monitoring in the Northern Plains region. In addition, more
than 70 agricultural research stations and farms, representative of most
agricultural MLRAs, are located across the Northern Plains.
Research and collaboration from these sites will provide valuable insights on
natural resource conditions and trends into the next century.
Conclusion
The NRCS recognizes that the Northern Plains region is a land of extremes in
soils, climate, crops, and animal agriculture. Northern Plains farmers and
ranchers have made substantial progress in soil and water conservation since the
1930s and especially in the past ten years, as documented by the 1992 National
Resources Inventory.
The agricultural community's progress in reducing wind and water erosion on
croplands and rangelands often has exceeded the national norms. The
stabilization of and net gains of wetlands over the past ten years are
significant accomplishments (especially since the national trend was slightly
negative) and have improved wildlife populations, increased flood storage
capacity, and contributed to carbon sequestration.
Similarly, the 14.7 million acres of land submitted to the Conservation
Reserve Program contributed to successes in maintaining wildlife populations,
reducing wind and water erosion, and supporting carbon sequestration in Great
Plains soils. Furthermore, these accomplishments occurred during a period of
greater climatic variability and stress, including such events as the
"Drought of 1988."
However, more than 130,000 acres of CRP lands were released in 1995. The
importance of CRP will not be apparent until the region experiences another
extended drought analogous to that of the Dust Bowl years. With 97 million acres
of fragile soils in the region, the natural and agroecosystems have little
capacity to adapt to a changing environment.
Soil quality and health issues in the region require more extensive
evaluation than currently possible through the NRI or soil survey process.
Saline seep development, alkalinity, carbon storage, and wind erosion are
dominant soil quality concerns. Over the longer term, how will these soils and
landscapes respond, physically and chemically, to climate changes?
Water quality problems are well recognized in the region, particularly along
the major drainages where irrigated corn monoculture occurs in association with
soils of high leaching potential. The Central Platte River reach may serve as a
good barometer for progress in reducing nitrate and atrazine levels in
groundwater.
The decrease in forests on nonfederal lands, although minor in extent, may be
signaling movement of timber harvesting from federal lands. The Northern Plains
region also has a large hidden infrastructure across the landscape —windbreaks.
Since 70 to 80% of the windbreaks need some type of renovation to maintain their
function, the past successes recorded across the region in reducing wind erosion
may be at risk. With the initiation of the Wetlands Reserve Program, wooded
riparian corridors should expand and are hoped will offset CRP releases.
Rapid urban growth along the Colorado Front Range, and increasing irrigation
demands, particularly in Nebraska, are reducing downstream flows and depleting
major aquifers in the Northern Plains region. The NRCS SNOTEL stations in the
headwaters will become increasingly important for forecasting water supply,
particularly under an uncertain climate.
Paralleling water supply issues, the loss of prime farmlands —which are the
soils with the best set of physical properties for soil moisture retention—
will become increasingly important in periods of high climatic variability. The
regional research and monitoring framework will improve our land resource and
climate databases and provide important information for natural resource
analysis.
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Appendix A
(MFS
notes: "Appendix A" is a listing of related programs. These are
generally NRCS and state programs. Please see the original text for this
listing. Works of several of the
cited authors are available on the "Sustainability Authors" page here.)
______
* America's Northern Plains: An
Overview and Assessment of Natural Resources. August 15, 1997.
U.S. Dept. of Agriculture, Natural Resources Conservation Service.
See
at Northern Prairie Wildlife Research, Jamestown, ND
< http://www.npwrc.usgs.gov/resource/othrdata/amnorpln/amnorpln.htm
>
Written copies of the study are available at:
Strategic Planner
NRCS, Northern Plains Regional Office
Federal Building, Room 240
100 Centennial Mall North
Lincoln, NE 68508-3866
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