**3. Results and discussion**

### **3.1 Land-use changes in Nebraska from 2006 to 2012**

In Nebraska, 43% of the land was in croplands, and the other 45% remained in grasslands in 2006 and 2012. Between 2006 and 2012, 250,000 ha of grassland were converted to cropland at the rate of 41,670 ha year<sup>−</sup><sup>1</sup> (**Table 1**). At the grassland- to cropland-converted sites, 92% had land capability classes that were of 4 or less. These data suggest that based on LCC scores, land-use change occurred primarily on suitable land and therefore based on the soil characteristics should be considered sustainable if appropriate practices are followed.

**7**

from 2006 to 2012.

*Soil and Land-Use Change Sustainability in the Northern Great Plains of the USA*

24.66 (0.58)

24.46 (3.17)

10.61 (0.41)

30.35 (1.68)

(8.45)

30.71 (2.75)

18.29 (1.48)

19.74 (8.95)

5.95 (0.68)

**Land capability class (LCC) within a category with confidence interval for each proportion in parentheses LCC 1 LCC 2 LCC 3 LCC 4 LCC 5 LCC 6 LCC 7 Estimated** 

> 0.15 (0.05)

1.09 (0.76)

1.41 (0.16)

0.10 (0.12)

0.93 (1.81)

1.11 (0.62)

0.19 (0.17)

1.32 (2.56)

1.48 (0.35)

7.71 (0.36)

22.83 (3.09)

60.75 (0.64)

2.98 (0.62)

9.26 (5.47)

20.26 (2.40)

12.92 (1.28)

42.11 (11.10)

70.14 (1.31)

0.04 (0.03)

5.02 (0.29)

0.46 (0.40)

0.08 (0.11)

6.07 (0.69)

0 0 0 15

0 0 0 9

**2006–2012 % ha × 1000**

0 36.36 (14.20)

12.02 (0.44)

27.17 (3.28)

13.59 (0.45)

13.49 (1.25)

32.41 (8.83)

26.46 (2.63)

10.40 (1.17)

19.74 (8.95)

10.60 (0.88)

Crop-grass 0 50 (49) 0 50 (49) 0 0 0 6

0 28.57 (33.47)

In Nebraska, the state was separated into eastern and western portions. The eastern portion contained three NASS regions (northeast, east, and southeast), whereas the western region contained five regions (northwest, southwest, north, central, and south).

to cropland between 2006 and 2012. At these converted sites, 89.8% had LCC values ≤ 4. In western Nebraska, 120,000 ha grassland at an annual rate of 20,000 ha year<sup>−</sup><sup>1</sup> were estimated to change from grassland to cropland category. At these converted

Between 2012 and 2014, 110,000 ha, at a rate of 55,000 ha of grassland year<sup>−</sup><sup>1</sup>

were converted to cropland. At these sites, 83.8% had LCC values ≤ 4 (**Table 2**). This

, were converted

**land**

7130

10750

1310

3550

9440

0 250

0 3580

0 130

0 120

that was observed

,

In eastern Nebraska, 130,000 ha grassland, at a rate of 21,670 ha year<sup>−</sup><sup>1</sup>

*Land-use change in different land capability classes of Nebraska from 2006 to 2012.*

sites, 56.6% occurred on soils with LCC values ≤ 4.

**3.2 Land-use changes in Nebraska from 2012 to 2014**

rate of change represents an increase from the 41,670 ha year<sup>−</sup><sup>1</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.84781*

**Change category**

Nebraska

East

West

**Table 1.**

Crop-crop 7.42

Crop-grass 9.09

Grass-crop 2.72

Grass-grass 0.37

Crop-crop 11.80

Crop-grass 14.29

Grass-crop 4.63

Grass-grass 1.67

Crop-crop 2.59

Grass-grass 0.06

(0.35)

(8.67)

(1.20)

(0.08)

(1.18)

(25.92)

(3.96)

(0.76)

(0.61)

(0.07)

Grass-crop 0 17.11

47.95 (0.67)

54.55 (15.01)

21.74 (3.04)

7.58 (0.35)

41.11 (1.79)

57.14 (36.66)

18.87 (2.33)

55.49 (1.90)

(8.47)

4.96 (0.62)

25 (8.17) 27.78


*Soil and Land-Use Change Sustainability in the Northern Great Plains of the USA DOI: http://dx.doi.org/10.5772/intechopen.84781*

#### **Table 1.**

*Land Use Change and Sustainability*

**2.1 Assessing land-use change**

loess and glaciated till soils. The Nebraska Sand Hills are contained almost entirely within the Nebraska North NASS region, and it represents one of the most unique and homogenous ecoregions in North America. The Sand Hills are one of the largest

The method to assess land use was previously discussed in Reitsma et al. [4] and summarized below. South Dakota has nine National Agricultural Statistics Service (NASS) regions (USDA-NASS, 2015) that include the northeast (NE), south east (SE), north central (NC), east central (EC), central (C), south central (SC), northwest (NW), west central (WC), and south west (SW). Similarly Nebraska has eight NASS regions that include the northwest (NW), north (N), northeast (NE), central (C), east (E), south west (SW), south (S), and south east (SE) (**Figure 1**). Stratified random sampling approach was used for sampling and within each of 17 USDA-NASS reporting districts. In each NASS region, 1600 sampling points were randomly identified using ESRI® ArcMap 10.2.2. These points were laid over high-resolution imagery, obtained from the US Department of Agriculture (USDA), Farm Service Agency (FSA), National Agricultural Imaging Program (NIAP) (USDA-FSA, 2013). The NAIP imagery for 2006 had a 2 m resolution, and the 2012 and 2014 imagery had a 1 m resolution. At each point (8 by 8 m), the dominant land use (cropland, grassland, habitat, non-Ag, and water) was visually identified (for 2006, 2012, and 2014). In South Dakota, 43,200 points in total were visually classified (14,400 points each year), whereas in Nebraska, 38,400 points were classified (12,800 points each year). For validation of our visual assessment and classification system, we randomly selected 100 sampling points from 17 different counties in South Dakota. The predicted management based on the remote sensing data (visual classification) was

areas of semiarid grass-stabilized sand dunes in the world [28].

identical to the known management at these points 100% of the time.

centages of soils within a LCC category as reported by Reistma et al. [4].

**3.1 Land-use changes in Nebraska from 2006 to 2012**

converted to cropland at the rate of 41,670 ha year<sup>−</sup><sup>1</sup>

sustainable if appropriate practices are followed.

Land capability class (LCC) and dominant subclass were obtained from the Soil Survey Geographic (SSURGO) data set by superimposing the sampling points over SSURGO [29]. At these points, the LCC value was determined [24]. LCC subclasses are used to help define the limitation. The most common subclass limitations are erosion hazard (e), wetness (w), rooting-zone limitations (s), and climate (c). However this was different than Reitsma et al. [4] where the LCC value was the sum of the component soils within a mapping percent multiplied by its numeric LCC value. This change in classification approach may result in slightly different per-

In Nebraska, 43% of the land was in croplands, and the other 45% remained in grasslands in 2006 and 2012. Between 2006 and 2012, 250,000 ha of grassland were

cropland-converted sites, 92% had land capability classes that were of 4 or less. These data suggest that based on LCC scores, land-use change occurred primarily on suitable land and therefore based on the soil characteristics should be considered

(**Table 1**). At the grassland- to

**2.2 Assessing changes in soil quality**

**3. Results and discussion**

**6**

*Land-use change in different land capability classes of Nebraska from 2006 to 2012.*

In Nebraska, the state was separated into eastern and western portions. The eastern portion contained three NASS regions (northeast, east, and southeast), whereas the western region contained five regions (northwest, southwest, north, central, and south). In eastern Nebraska, 130,000 ha grassland, at a rate of 21,670 ha year<sup>−</sup><sup>1</sup> , were converted to cropland between 2006 and 2012. At these converted sites, 89.8% had LCC values ≤ 4.

In western Nebraska, 120,000 ha grassland at an annual rate of 20,000 ha year<sup>−</sup><sup>1</sup> were estimated to change from grassland to cropland category. At these converted sites, 56.6% occurred on soils with LCC values ≤ 4.
