This project assembles historical measures of soil degradation and its effects on agricultural productivity in India and China, countries containing 44 percent of the population of all developing nations. Now that population growth is near the fastest rate in all history, how fast is productive land being lost to erosion, aggradation, salinity, alkalinity, and cities? How fast has the net soil loss really been? How much has it cost? The techniques developed here can become a model for solving other debates over trends in soil quality. Most estimates of soil degradation are erosion estimates. These estimates suggest enormous losses. For example, it is estimated that rivers carry 24 billion tons of sediment to the ocean each year, compared with only 9 billion tons before the introduction of agriculture, grazing and other human activities. But such studies give gross measures of soil loss, not the net measures that are closer to the productivity measures needed in order to assess the productivity effects of erosion. These measures lack information on the earlier amount and quality of soil, for comparison with water levels. Instead of a chain of snapshots over time, we are asked to judge movement from a single snapshot. In contrast, this project assembles and analyzes six main data sets on soil qualities and agricultural productivity in China from the 1930s to the 1980s and three main data sets for land quality in India from 1950 to 1984. Considerable time is spent on direct comparisons of soil data from cultivated lands within each county in China and India. The productivity consequences of land attributes will be estimated from these data. Finally a range of related hypotheses about land tenure and the role of specific policies will be rigorously tested.
