Research Progress Report 307 May, 1967
Fertilizer Used on Crops and Pasture in Indiana: 1964 Estimates, With Comparisons to 1959 and 1954
George D. Irwin and Jerry V. Mannering 1/

Inexpensive commercial fertilizers represent a major technological development in crop production, and the most important source of recent increases in yields. Following each census of agriculture, USDA agronomists and economists cooperate with state university specialists in bringing together available statistics and current judgment to get an up-to-date, comprehensive picture of changes in fertilizer use. The information is valuable to a wide variety of people in farming, fertilizer manufacturing, education and extension work, research, and farm policy planning.

The census of agriculture, taken every fifth year, obtains from farmers benchmark data on acreages of crops fertilized, and on tons of dry and liquid materials used. Reports collected yearly from fertilizer manufacturers provide data on total sales of dry and liquid materials, and on tonnages of nitrogen, phosphorus, and potassium contained
in these materials. A third source of information is sample surveys made for major crops in selected states to get estimates of the percentage of acreage receiving each fertilizer nutrient and the average nutrient application per acre. Estimates made in this report are based on these three data sources, plus expert judgment to fill in the gaps. 2/

This report summarizes estimates derived for the 1964 crop year for Indiana, and makes comparisons with 1959 and 1954. At a later date, data for Indiana will be combined with that from other states in a national report for 1964, updating the 1959 data in USDA Statistical Bulletin 348.

A Look Back over 20 Years
Four trends dominate the changing pattern of commercial fertilizer use since World War II. Since 1945:

1/ Agricultural Economist, Farm Production Economics Division, Economic Research Service, U.S. Department of Agriculture; and Soil Scientist, Soil and Water Conservation Research Division, Agricultural Research Service, U.S. Department of Agriculture, respectively, stationed at Purdue University, Lafayette, Ind.
2/ Advisers included the following staff members at Purdue University: Drs. A. J. Ohlrogge, M. W. Phillips, and M. L. Swearingin, of Agronomy; Drs. G. E. Wilcox and F. H. Emerson of Horticulture.

PURDUE UNIVERSITY • Agricultural Experiment Station • Lafayette, Indiana