Effect of Certified Organic Products on Soybean Aphid

The soybean aphid (Aphis glycines), native to China, has become the most economically damaging insect in soybeans in northeast Iowa. Soybean aphid may have up to 18 generations per year, beginning with overwintering eggs on the alternate host buckthorn. In spring, winged aphids migrate from buckthorn to nearby emerged soybeans. Generations advance in these fields, and then another winged migration occurs in summer spreading from these fields to others. A third migration occurs in fall with aphids moving back to buckthorn. Depending on the season, soybean proximity to buckthorn, and soybean aphid migration patterns, populations of aphids tend to peak in soybeans anywhere from late July to early September. With higher aphid populations, the production of honeydew (the excrement of the aphid) and the resulting black fungus that grows on it (sooty mold) may become apparent. Aphid feeding may cause stunted plants, reduced pods and seeds, and may also transmit viruses that could cause mottling and distortion of leaves, reduced seed set, and discolored seeds.

Comparison of Organic and Conventional Crops at the Neely-Kinyon Long-term Agroecological Research Site

The Neely-Kinyon Long-term Agroecological Research (LTAR) site was established in 1998 to study the long-term effects of organic production in Iowa. Treatments at the LTAR site, replicated four times in a completely randomized design, include the following rotations: conventional Corn-Soybean (C-S), organic Corn-Soybean-Oats/Alfalfa (C-SO/A), organic Corn-Soybean-Oats/AlfalfaAlfalfa (C-S-O/A-A) and Corn-SoybeanCorn-Oats/Alfalfa (C-SB-C-O/A). On April 13, 2011, Badger oats were underseeded with BR Goldfinch alfalfa at a rate of 90 lb/acre and 15 lb/acre, respectively. Following harvest of the organic corn plots in 2010, winter rye was no-till drilled at a rate of 75 lb/acre on October 20, 2010.

Soybean Yield Response to Rhizobium Inoculation on Converted Grass Pasture

Much of the soybean plant's nitrogen requirement is supplied through nitrogen fixation when atmospheric nitrogen is converted into a usable form for the plant. Nitrogen fixation is critical for producing higher yield in soybean. For nitrogen fixation to occur, nitrogen-fixing bacteria (genus Rhizobium) need to be present in the soil. If soils do not already contain a high population of Rhizobium, these bacteria can be added either as a liquid or granular peat inoculant, or as a peat-based powder. The different forms can be seed applied or used in-furrow.

Aphids in Corn Research

Corn, Zea mays L., is the most abundant field crop in Iowa, and there are many insect pests associated with this field crop. Although aphids are not typically economically important in corn, recent observations have indicated several aphid species developing heavy populations in northwest Iowa and southwest Minnesota. Historically, the corn leaf aphid, Rhopalosiphum maidis (Hemiptera: Aphididae), has been the most abundant aphid species in corn; however, the bird cherry oat aphid, R. padi (Hemiptera: Aphididae), and several other species have also been detected. Recent observations show a shift to populations peaking later in the summer. Damage potential and management guidelines for aphids in corn are not well defined and this research is aimed at developing economic threshold and sampling protocols.

Weather Inputs to a Warning System for Sooty Blotch and Flyspeck of Apple

Sooty blotch and flyspeck (SBFS) is a mid- to late-season disease of apple. SBFS fungi show up as dark smudges and clusters of black dots on the fruit surface. Since blemished fruit are downgraded, crop losses can exceed 90 percent of the fresh market value.

Converting Land from Poplar Tree Bioenergy Planting to Cropland: An Example

Many landowners ask about the process and costs for returning land to crop production after trees are cut for biomass. A field on the Squaw Creek bottom, Story County, Iowa was planted to hybrid poplar trees in spring 2000. The trees were planted in rows with a 10-ft spacing. The trees were cut in spring 2010. The resulting field was four acres, and this is the account of the first corn crop in 2011 on the area.

Armstrong and Neely-Kinyon Research Farms Summary

Includes Farm and Weather Summary, Research Farm Projects, Acknowledgements and Information on Experiments in Previous Annual Progress Reports.

Northwest and Allee Farms Summary

Includes Northwest Research Farm Summary, Projects at Sutherland and Allee Demonstration Farm Summary.

Evaluating Degradable Mulches for Muskmelon Production

Plastic mulches can provide vegetable growers with earlier crop maturity, increased yields and quality, improved disease, insect and weed control, and more efficient fertilizer and water use. However, standard polyethylene mulches must be removed and disposed of at the end of each season, which is a dirty and costly undertaking. One solution to this problem has been the development of degradable mulches that can be left in the field after harvest to disintegrate and be incorporated into the soil. Unfortunately, degradable mulch performance hasn’t always met expectations. And now there are different types of degradable mulches being aggressively marketed creating questions about which one is best. The objective of this study was to evaluate three types of degradable mulches for ease of use, speed of breakdown, and how they influence transplanted muskmelon performance.

2011 Home Demonstration Gardens

Themes for the 2011 Home Demonstration Garden Field Days included 1) a storybook garden (vegetables and annual flowers named after characters in classic fairytales), 2) warty pumpkins, 3) new flowers and vegetables, 4) summer squash named after types of cats, 5) pole beans, and 6) sunflowers without pollen for use as cut flowers.

Evaluation of Foliar Fungicides and Insecticides on Soybean

Use of foliar fungicides and insecticides are an effective strategy for managing foliar diseases on soybean. There are many different fungicides and insecticides available for use currently in Iowa. Iowa State University personnel assessed the success of fungicides and insecticides across Iowa. This study was conducted at six locations: Sutherland (NW), Kanawha (NC), Nashua (NE), Ames (central), Crawfordsville (SE), and Lewis (SW) research farms (Figure 1).

Sweet Corn Cultivar Trial

The 2011 sweet corn cultivar trial evaluated 20 sugary enhanced (se) and synergistic (se/sh2) cultivars having bicolored kernels to identify good production and ear characteristics for local marketing or short-distance shipping.

Evaluation of the Newly-developed, Least-cost Experimental Diet for Bluegill at Commercial Densities in Ponds

A substantial need exists to reduce costs and develop more nutritionally adequate diets for established as well as emerging aquaculture species in the North Central Region (NCR). The study evaluated a diet for juvenile northern bluegill (Lepomis macrochirus) that is significantly less costly than currently available diets for sunfish, while yielding a growth rate that is at least equal to an industry standard sunfish diet. Such a diet formulation is now available to the NCR as the result of a recently funded North Central Regional Aquaculture Center (NCRAC) project.

Soil and Plant Fertility Management for Soybeans

Producers utilizing a two year rotation of corn and soybean often apply fertilizer on a biannual basis, spreading recommended amounts of phosphorus and potassium for both crops prior to corn establishment. This approach minimizes application costs and is in accordance with university fertility recommendations that have found a low probability of fertilizer yield response when soils tested at the medium/optimum level or above. However, the field trials on which these state recommendations were developed are often several decades old. Increases in average corn and soybean yields and associated increases in crop nutrient removal rates have called into question the validity of these recommendations for current production environments. This study investigated the response of soil test levels and grain yield to annual and biannual fertilizer applications made at 1x and 2x rates of current university fertilizer recommendations.

Species Diversity is a Good Predictor of Prairie Plant Persistence in Restorations

Prairie restoration projects sometimes fail because of heavy invasion by invasive weeds, especially if they are not intensively managed. Few restoration projects are sampled after the first few years post-establishment, and little is known about what predictors are significant in maintaining restored communities over the very long term. Here, we stopped weeding experimental restoration plots to determine if persistence (that is, remaining unchanged after weeds are allowed to invade) of native prairie in western Iowa was related to planted species diversity