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Medieval Archaeology, 23, 223-225, The roof of the chapel, although drastically reconstructed c 1300, provides the most complete evidence for late Saxon ridged roofing of stone buildings (cf Sompting and St Martin's Canterbury). The rafters were set in inclined trenches in the tops of the side-walls. The Norman windows and doorway may be later insertions into the original fabric.

This article examines the effects of increasing market concentration level in the U.S. nitrogen fertilizer industry. Results indicate that the costs of market power are greater than the benefits of market concentration, in terms of manufacturing cost efficiency. To provide a stable nitrogen fertilizer supply at a relatively low price, it may be necessary to control natural gas price and/or reduce new import barriers from Middle East and former member states of the Soviet Union, where low cost gas is produced as a byproduct. Keywords: Nitrogen fertilizer, oligopoly, economies of size, market power, cost-efficiency.

This article evaluates structural changes in the U.S. nitrogen fertilizer industry by using a decomposed Negative Binomial Regression model. Results indicate that the U.S. nitrogen fertilizer industry can be characterized as an industry involving price leadership in oligopoly. Declining profit-margins might have forced fertilizer producers to consolidate and eliminate duplicate operations. The market concentration level is expected to intensify as the natural gas price rises.

This research presents a competitive dynamic model to evaluate the economic and groundwater quality benefits resulting from the adoption of soil/water nitrogen testing. The model is applied to an irrigated corn production county in the Nebraska Mid-State area where the groundwater contamination level from nitrates is reported to be, on average, 18.7 parts per million (ppm). Adoption of nutrient management practices would result in increased economic benefits to farmers and reduced nitrate stocks in groundwater.

Pesticides used on major crops more than doubled during 1964-82 (from 233 to 612 million pounds of active ingredients). Nitrogen, phosphate, and potash use for all purposes (agriculture and nonagriculture) rose from 7.5 million pounds in 1960 to a record high of 23.7 million pounds in 1981. These increases in pesticide and fertilizer use were a result of a larger crop acreage, higher application rates per acre, and increased proportions of acres treated with chemicals. Since the early 1980's, pesticide and fertilizer use in U.S. agriculture has declined with crop acreage, and amounted to 574 million pounds of pesticides and 20.7 million tons of fertilizers in 1992. Corn leads other crops, by a substantial margin, in the total quantity of pesticides and fertilizers used. Insecticide use on corn can be greatly reduced by rotating crops and significant reductions in herbicide and nitrogen use can be achieved by adjusting application timing and method.

The rapid growth in fertilizer consumption throughout the sixties and seventies peaked at 23.7 million nutrient tons in 1981. After falling to 18.1 million tons in 1983, use has remained relatively stable, ranging from 19.1 to 21.8 million tons during 1984-93. Use has declined from its peak level because of fewer planted acres and stabilizing rates of application. Farm fertilizer prices, while stable or declining during the sixties, have varied widely since 1973. This bulletin includes quarterly or semiannual time series for farm fertilizer prices, annual, farm and wholesale fertilizer price indexes, fertilizer consumption by plant nutrient and major selected products, consumption of mixed fertilizers and secondary and micronutrients, and statistics on fertilizer use per acre by nutrient in the major producing States for corn, cotton, soybeans, and wheat.

The United States is the world's largest phosphate exporter and the world's largest potash importer. The U.s. nitrogen trade balance, relatively stable before 1983, has shifted as the United States became a net importer of nitrogen beginning in 1983. This bulletin includes statistics for 1970-91 on U.s. imports and exports of selected fertilizer materials, world and U.S. imports and exports of nitrogen, phosphate, and potash, and U.S. import origins and export destinations for selected fertilizer materials.