The researchers studied the distribution and abundance of the plant species of farmland woodlots in central Iowa, with particular emphasis on the differences in species composition between sites currently or recently grazed by cattle versus those that had not been grazed for more than 50 years. In addition, various attributes of common species and less common (restricted) species were compared.

Throughout the Cornbelt eco-region, nitratenitrogen (NO3-N) is the most frequent pollutant exceeding the U.S. Environmental Protection Agency's maximum contaminant limits for municipal drinking water supplies. Agricultural fertilizers that leach or run off from row-cropped fields are the principal source of NO3-N. This potential contamination poses a health concern that is attracting increasing attention among the urban and rural populace alike.

A tree shelterbeit comprised of four rows of hybrid poplars was established near Ogden, Iowa in 1992 to evaluate shelterbeit characteristics and impacts on soil water content and crop growth andyieid. Major emphasis was on testing crops of corn and soybeans. The first three years saw little effects from the shelterbeit, and data from these years will be used to develop a baseline for future measurements. In the fourth and fifth years, corn yield patterns suggested that the shelterbeit increases yields in the zone leeward from the shelterbeit. Soybeans have not shown a response to the presence of the shelterbeit.

Non-timber specialty forest products show potential for farmers hoping to diversify their operations. This project and survey evaluated the interest in and obstacles to the production and marketing of these crops.

Those interested in planting black walnuts have lacked information about the best cultivars available for planting in Iowa. This project initiated long-term studies of several varieties of black walnut trees to determine the best cultivars for Iowa growers.

Weed competition and economics are two common barriers to Iowa farmers' investing in tree plantings. This project examined seven weed control strategies and investigated productivity of small grain/forage combinations raised with trees in an effort to suggest management options that would encourage tree planting in the state.

Yield data for corn (eight years) and soybeans (six years) were collected and analyzed to determine the impacts of a hybrid poplar shelterbelt on crop production on a central Iowa farm.

Over three years, small willow cuttings ("posts") cut from local sites were planted into the stream bank on six sites along the Middle Raccoon River. These posts stabilize the bank, reducing erosion and protecting water quality. In addition, unlike most riparian buffer planting techniques, they do not take land out of agricultural row-crop production. They also provide shading and enhance wildlife habitat. Plantings are most successful if cut while dormant, planted on rivers or streams that have less than 50,000 acres drainage, and inspected regularly for insect and beaver damage (so that preventive measures may be taken where indicated). This technique was demonstrated to the public via field days and media coverage, and results of a survey assessing attitudes about adoption of the technique are being analyzed.

Shelterbelts have the potential to influence growth and yield from various cropping systems. On-farm tests were conducted to determine how shelterbelts interacted with corn, corn/soybean, and strip intercropping.

The goal of this initial three-year project was to establish the pawpaw trees and bring them to fruiting stage. This was part of a long-term effort to evaluate the potential for an Iowa pawpaw tree fruit crop.