Corn Response to Sulfur Application Rate

Historically, sulfur (S) application has not been recommended on Iowa soils for corn and soybean production. Soils supply, or a combination from sources such as soil organic matter, profile sulfate, manure, and precipitation have met crop S needs. However, over the past few years, S deficiencies in alfalfa and corn have been documented. Large crop yield responses have been measured in some fields containing soils with low organic matter, side-slope landscape position, or coarse soil texture, especially in northeastern Iowa. The objective of this study was to determine S response in corn and soybean in north-central Iowa.

Intensive Rotational Grazing of Steers at the Andrew Jackson Demonstration Farm

Fifty head of crossbred steers started grazing 51 acres of pasture on May 1 in a rotational grazing system using a variable density paddock system. Twenty-two head grazed 92 days, 27 grazed 140 days, and one steer died. A total of 11,922 pounds was produced on 5,804 animal-days of grazing. The average daily gain was 2.02 pounds for group 1 and 2.07 for group 2. The stocking rate for the first 92 days was .98 steers per acre and .53 for the final 48 days. The animal days of grazing per acre was 113 and the pounds of gain per acre was 233. Total return for land, labor and management for the demonstration was $2,829.76 or $55.49/acre.

Management Intensive Grazing of Stockers at the Andrew Jackson Demonstration Farm (1996 – 1998)

The Andrew Jackson Demonstration Farm (AJDF) is located in central Jackson County in east central Iowa. A board of directors operates the farm for the purpose of demonstrating different production practices and management strategies. From 1996 to 1998 management intensive grazing practices and the grazing of stockers on a combination of permanent and tillable pasture have been demonstrated. Grazing strategies or practices demonstrated during these years included establishment of Eastern Gamagrass and Big Bluestem, variable density grazing, measuring forage on-offer, estimating dry matter intake, grazing corn, pasture renovation, and fencing and water systems. Production performance data were gathered for the three years stockers that were grazed. During this time the stockers averaged 121 animal days of grazing, a 1.1 head per acre stocking rate, a 1.85 pound average daily gain, and 228 pounds of gain per acre. The financial measures evaluated the value of gain on pasture and the pasture cost of the gain. The value of gain per pound was positive for 1996 and 1997 at $.58 and $.52 whereas in 1998 it was a -$.04. Pasture costs per pound of gain ranged from $.12 to $.16. Production performance is only one part of the profit picture when evaluating a stocker operation. Buysell margins are the other significant part that can greatly impact the profit potential of a summer grazing program.

Ammonia Emissions Rate from Composted Laying Hen Manure

During the past five years we have developed three emission calorimeters (EC) that can be used to evaluate mass generation and utilization of gasses. We have tested various treatments that significantly reduced ammonia generation by laying hen manure (Harrison and Koelkebeck, 2002; 2003).