The historic stream flooding and intense rainfall across the upper Mississippi River Basin during summer 1993 had an immediate effect on near-surface unconsolidated aquifers by raising the water levels closer to the land surface. The objective of this study was to determine if this flooding also had immediate effects on ground-water quality. Water samples were collected during September and October 1993 from 110 wells completed in near-surface unconsolidated aquifers and were analyzed for herbicides, herbicide metabolites, inorganic nutrients, and volatile organic compounds. The results of these samples were compared with those obtained during summer 1991 or 1992. Water samples from the Missouri River alluvial aquifer had a fourfold increase in the frequency of herbicide detection. There also appears to be a relation between increases in total herbicide concentration and the occurrence of stream flooding near a well. Water samples from wells that had at least a 20% increase in dissolved-oxygen concentration had the greatest frequency of substantial changes in total herbicide concentration and substantial increases in nitrate concentration.

Agricultural Productivity: Measurement and Sources of Growth addresses measurement issues and techniques in agricultural productivity analysis, applying those techniques to recently published data sets for American agriculture. The data sets are used to estimate and explain state level productivity and efficiency differences, and to test different approaches to productivity measurement. The rise in agricultural productivity is the single most important source of economic growth in the U.S. farm sector, and the rate of productivity growth is estimated to be higher in agriculture than in the non-farm sector. It is important to understand productivity sources and to measure its growth properly, including the effects of environmental externalities. Both the methods and the data can be accessed by economists at the state level to conduct analyses for their own states. In a sense, although not explicitly, the book provides a guide to using the productivity data available on the website of the U.S. Department of Agriculture/Economic Research Service. It should be of interest to a broad spectrum of professionals in academia, the government, and the private sector.