Surface Waters: Ammonium is Not Ammonia – Part 3
By John Sawyer, Department of Agronomy and Matt Helmers, Department of Agricultural and Biosystems Engineering
Integrated Crop Management News
Links to these articles are strongly encouraged. Articles may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If articles are used in any other manner, permission from the author is required.
Consider Effects on Seedbed Before Tilling Wet Soil
By Mark Hanna, Department of Agricultural and BioSystems Engineering, and Mahdi Al-Kaisi, Department of Agronomy
The current weather conditions of frequent rain caused saturated conditions in most Iowa soils. Tilling soil for drying the soil surface or weed control at this time may have significant negative impacts on creating proper seedbed conditions and increase soil compaction.
Beware of a Dangerous Invasive Weed -- Updated
By Mike Owen, Department of Agronomy
Upon further investigation about the location of “local” infestations of the highly invasive giant hogweed, it was determined that the Wisconsin location is in Iron County which is located at the northern boundary between Wisconsin and the Upper Peninsula of Michigan (see colored area on the map). Gogebic County, Michigan also has or had infestations of giant hogweed. The U.S. Forest Service is working diligently to eradicate these populations.
Seeding Rates in Relation to Maximum Yield and Seed Costs
By Roger Elmore and Lori Abendroth, Department of Agronomy
Increased seeding rates have ignited corn yield increases over the years. If seeding rates are the spark, hybrid genetics fuel the increase. It takes both high seeding rates and high-yielding hybrids that can tolerate increased plant-to-plant competition to maximize yields. If hybrids were not bred to tolerate increased seeding rates, we would have fields of flat corn at harvest. Older hybrids simply cannot tolerate today’s seeding rates without severe lodging and/or barrenness.
It’s a Late Spring: Should You Apply Nitrogen or Plant Corn?
By John Sawyer and Roger Elmore, Department of Agronomy
Our best information from planting date experiments show that corn yields are reduced as we plant into the second half of May. However, looking at planting progress and corn yields over the years, we see that although yields are increasing and in general we are planting earlier every year, above average yields can occur with delayed planting and below average yields can occur with early planting (see Sidebar article ‘Corn Planting Progress‘ from Wisconsin).
Surface Waters: Ammonium is Not Ammonia – Part 2
By John Sawyer, Department of Agronomy
A previous article explained the difference between ammonium and ammonia, the relationship between the two nitrogen forms and the implication of a combined (ammonium-N plus ammonia-N) analysis related to water quality criteria for aquatic life. This article focuses on the implication of ammonia and ammonium for chlorination of drinking water.
Field Testing of N-Hibit™ Seed Treatment in Iowa*
By Greg Tylka and Chris Marett, Department of Plant Pathology
N-Hibit™ is a seed-treatment that contains harpin protein, a compound that can stimulate plant defense responses. N-Hibit™ is now being sold in the United States for management of the soybean cyst nematode (SCN). Iowa State University evaluated the effects of N-Hibit™ seed treatment on soybean yield and SCN population densities in experiments at nine locations throughout Iowa in 2007.
Don’t Use More Pressure than Needed on Wet Soils
By Mark Hanna, Department of Agricultural and Biosystems Engineering
Many Iowa planter operators are faced with wet soil conditions this spring. Operators will want to wait for suitable conditions to avoid “mudding in” a crop with significant investments in seed, fertilizer, machinery and time.
Adapting to Alfalfa Winterkill and Winter Injury
By Stephen K. Barnhart, professor, Department of Agronomy
Significant areas of alfalfa winterkill are now evident in Iowa. The worst areas are along the Highway 20 corridor in eastern and northeast Iowa, with notable losses to the Minnesota border in Iowa and also in random fields in other parts of the state. Frozen alfalfa crown and upper taproot tissue is not able to recover. Evidence of the injury was delayed because some plants began to green-up and then died. Plants that still exhibit good taproot and crown tissue are likely unaffected.
When is it Too Late Plant Forages?
By Stephen K. Barnhart, Department of Agronomy
Spring hay and pasture seedings are normally done from late February through late April in Iowa. The extended period of wet weather in 2008 has many producers still waiting to get their forages planted.
Can they still successfully plant forage crops?