DOI: 10.5061/dryad.g1n25
title: Data from: Continuous corn and corn–soybean profits over a 45-year tillage and fertilizer experiment

description: Studies comparing profitability of tillage systems often examine narrow
 historic windows or exclude annual price fluctuations. This study uses a
 continuous corn (Zea mays L.) (CC; 1970–1990) and corn–soybean [Glycine
 max (L.) Merr.] (CS; 1991–2014) Tillage × Fertilizer study in somewhat
 poorly drained soils in southern Illinois to reconstruct partial annual
 budgets with historical prices for crops, fertilizers, lime, herbicides,
 fuel, labor, and machinery. Combinations of tillage (moldboard plow [MP],
 chisel tillage [ChT], alternate tillage [AT], and no-till [NT]) and
 fertilizer (Control, N-only, N+NPK starter, NPK+NPK starter, and NPK
 broadcast) treatments were evaluated. The CC profits were highest in
 NPK-applied treatments followed by N-only and Control. The MP treatments
 were similar to ChT and more profitable than NT, while AT fell between. In
 CS, NPK-applied treatments were similar regardless of tillage. Combined
 costs for herbicide, machinery, labor, and diesel were higher in MP and
 ChT systems than AT and lowest in NT, but were a small percentage of total
 costs (26.6, 26.0, 21.5, and 18.2%, respectively). Nitrogen fertilizer
 offered a return on investment of 396% in CC and 133% in CS while P
 & K returned 78% in CC and 109% in CS. Sensitivity analysis in CS
 showed that NT would be less profitable than MP if herbicide costs
 increased 850%. A 300% machinery cost increase would have made MP less
 profitable than NT. These findings suggest that since 1991 CS under NT
 carried the same potential for profit as other tillage systems under full
 fertility management.
description: Tillage x Fertility Crop
 Costs and Profits 1970 to 2014These data represent the
 costs and profit (in 2014 US dollars per acre) associated with each
 tillage x fertility treatment plot. These data were used for the analysis
 in the Trlica et al. 2017 manuscript. Data were converted from $/ac to
 $/hectare for publication, but per hectare data are not included
 here.TxF_Econ_model_output.csvNominal Prices 1970-2014Summary of nominal (not inflated to 2014 US dollars) prices of inputs per unit, commodity values per bushel of corn and soybean, and composited PPITW index (2011=100).prices_final.csvTillage x Fertility R script for data collation"TxF_Economics_data_collation_final.R" is the R script file used to process and data files and generate cost, price, and profit estimates used in Trlica et al. (2017). All costs and prices quoted in U.S. dollars ($). Additional price and index information gathered from other reports and sources integrated into final price sheet are detailed in the R script and in Trlica et al. (2017). The "Econ data" files can be used with this script if you direct it at the right file folder, should be able to reproduce all the output files that we used for analysis.TxF_Economics_data_collation_final.RAg_lime_2014-1970_priceEcon data file: "Ag_lime_2014-1970_price.csv" — Agricultural lime (CaCO3) price, applied to field, U.S. Average, 1970–2014 (USDA NASS Quick Stats download).Amm_nit_2014_1970_priceEcon data file: "Amm_nit_2014_1970_price.csv" — Ammonium nitrate price (nominal $/ton), U.S. Average, 1970–2014 (USDA NASS Quick Stats download).corn_price_USDANASSEcon data file: "corn_price_USDANASS.csv" — Corn sale price (nominal $/bu), U.S. Average, 1970-2014 (USDA NASS Quick Stats download)Gly_2014_2001_pricesEcon data file: "Gly_2014_2001_prices.csv" — Glyphosate price (4 lb ai/U.S. gal), U.S. Average, 2001-2014 (USDA NASS Quick Stats download).Herb_useEcon data file: "Herb_use.csv" — schedule of post-emergent herbicide applications used on No-till plots, 1970–2014: Gly_lbsai (Glyphosate, lbs a.i./ac), Para_lbsai (Paraquat, lbs a.i. per acre) See Cook and Trlica (2016).Labor_UnsortedEcon data file: "Labor_Unsorted.csv" — unsorted labor wage rates, U.S. Average, 2015–1978 (USDA NASS Quick Stats download).Lime_appl_2014_1970Econ data file: "Lime_appl_2014_1970.csv" — schedule of lime applications to the site by plot ID (tons per acre). Rates given for applications in 1975, 1983, 1991, 2001, 2012. See Cook and Trlica (2016).Mach_op_costsEcon data file: "Mach_op_costs.csv" — Operation costs for machinery activities, by implement type (determined from Illinois FarmDocs calculator tool, see Trlica et al. (2017))Mach_price_index_1990Econ data file: "Mach_price_index_1990.csv" — Machinery Totals (1990-index), index for Price Paid 1975-1990 (USDA NASS Quick Stats download).Mach_price_index_2011Econ data file: "Mach_price_index_2011.csv" — Machinery Totals, index for Price Paid (2011-index), 1990-2014 (USDA NASS Quick Stats download).Master_Yield_1970-2014_econEcon data file: "Master_Yield_1970-2014.csv" — table of corn yield and ancillary field data for 1970–2014 seasons. Data file identical to file used in Cook and Trlica (2016) (see Dryad Digital Repository doi:10.5061/dryad.7920c). Data missing entirely for years 1981, 2008 due to crop loss.Para_2008_2001_pricesEcon data file: "Para_2008_2001_prices.csv" — Paraquat price (2.5 lb ai/U.S. gal), U.S. Average, 2001–2008 (USDA NASS Quick Stats download).PPITW_2013-1975-1990indexEcon data file: "PPITW_2013-1975-1990index.csv" — PPITW (Prices Paid Index for Commodities and Services, Interest, Taxes, and Farm Wage Rates) (1990=100) for 1975–2013 (USDA NASS Quick Stats download).PPITW_2014-1990-2011indexEcon data file: "PPITW_2014-1990-2011index.csv" — PPITW (2011=100) for 1990–2014 (USDA NASS QuickStats download).soy_price_USDANASSEcon data file: "soy_price_USDANASS.csv" — Soybeans sale price (nominal $/bu), U.S. Average, 1970-2014 (USDA NASS Quick Stats download).Table7_Fert_prices_1960Econ data file: "Table7_Fert_prices_1960.csv" — Table 7 from report "Fertilizer Use and Price" listing price (nominal $/ton) of triple superphosphate (44-46%P) and potash/potassium chloride (60% K) 1960–2013 (see USDA Economic Research Service, https://www.ers.usda.gov/data-products/fertilizer-use-and-price.aspx)Urea_2014_1970_priceEcon data file: "Urea_2014_1970_price.csv" — Urea price (nominal $/ton), U.S. Average, 1970–2014 (USDA NASS Quick Stats download).Tillage x Fertility Econ data sample SAS codeThis is an example of the SAS code used to analyze the final dataset for the Trlica et al. 2017 publication.TxF_Econ_SASmixedmodel.txt