ers planted 8,875,000 acres of corn of which 8.4 million acres was planted for grain and 475,000 acres for silage. Some 58%, about 4.9 million acres, of the corn for grain and 31% of the corn for silage were irrigated. The fraction of all acres of corn that are irrigated varies greatly in the state. It is difficult to extract the “basin acres” from the statistics, because the census is created by county and not by watershed. Counties adjacent to the Platte River have irrigation coefficients ([irrigated acreage for corn for grain]/[total acreage for corn for grain]) of 54% to 96%. About 44% of soybean crops (207,000 acres) was irrigated in Nebraska in 2002. Where soils and topography are suitable but irrigation water is unavailable, dryland crops, such as wheat, may be grown. In 2002, 8% of wheat crops (129,000 acres) were irrigated in Nebraska (Nebraska Agricultural Statistics Service 2004).

In addition to crops, agriculture in the region includes livestock—predominantly feeding operations for beef cattle. In portions of the basin with rugged topography and without adequate access to irrigation water, open livestock grazing has been the dominant land use.

Surface-water diversions for irrigation began in the central Platte area as early as the 1850s and 1860s (Eschner et al. 1983). Irrigation-ditch or canal construction proceeded during the 1890s drought years, and use of groundwater for irrigation began in the late 1800s. Groundwater use increased in the early 1900s and again after about 1950 with the development of center-pivot irrigation systems (Figure 2-11). The percentage of farmland

Front Matter (R1-R36)

Summary (1-18)

1 Introduction (19-31)

2 Regional Context for Water and Species (32-72)

3 Law, Science, and Management Decisions (73-107)

4 Scientific Data for the Platte River Ecosystem (108-154)

5 Whooping Crane (155-185)

6 Piping Plover and Interior Least Tern (186-224)

7 Pallid Sturgeon (225-239)

8 Conclusions and Recommendations (240-257)

References (258-276)

Appendix A: Biographical Information on Committee Members (277-286)

Appendix B: Bird Species of Conservation Concern in Nebraska (287-290)

Appendix C: Confirmed Whooping Crane Sightings in Central Platte River Study Area, 1942-2003 (291-297)

Appendix D: Input Data for Figures 5-6 a and 5-6b (298-300)