Horticulture Research Station Summary

Includes Farm Staff, Farm and Weather Summary and Research Station Projects.

AgEdS/Hort 465 Class: Horticulture Enterprise Management

The production of local fruit and vegetables is a rapidly expanding segment of Iowa agriculture. The new ISU AgEdS/Hort 465 class trains future growers in the management and operation of diversified horticultural enterprises on an Iowa farm situation. Management of the finances, production, and marketing is performed by the students. The course is structured as a business and is guided through decisions made by student committees (finance, operations, production, and marketing committees). Each committee investigates the feasibility of a desired enterprise before coming together to make a final decision. The course was offered for the first time in 2011.

Thinning Scab-resistant Apples with Liquid Lime Sulfur Sprays during Bloom

Growing scab-resistant apple cultivars on fully dwarfing rootstocks increases the feasibility for producing organically grown apples in the Midwest. However, in an organic orchard, fruit thinning to optimize crop load must be done by hand at a very high labor expense. The alternative is biennial bearing and inconsistent supply to meet consumer demands. Recently, sprays containing organicapproved materials such as liquid lime sulfur, fish, and various vegetable oils, salts, and kaolin have been tried alone or in combination for thinning apples with some degree of success. Lime sulfur alone or in combination with spray oil was recently labeled for use in Washington state orchards. This study was undertaken to evaluate the effectiveness of liquid lime sulfur alone and in combination with spray oil applied at various times during bloom on thinning three scab-resistant apple cultivars under Iowa conditions.

Influence of Crop Load on Tree Growth, Yield, and Fruit Quality of Scab Resistant Apples at Harvest

Apple scab, caused by Venturia inaequalis, is a major disease affecting apple production. Breeding programs have developed over 30 releases of scab-resistant cultivars since 1970 with recent ones having much improved quality. Redfree and GoldRush are from a cooperative breeding program involving Purdue, Rutgers, and Illinois universities while Liberty was introduced from the Cornell University breeding program. For these cultivars to gain better acceptance, more information is needed on their cropping capacities and the effect of crop load on fruit quality attributes. Our study was conducted to determine the relationship between increasing crop load on tree growth, fruit size, and fruit quality variables of the three cultivars under Iowa conditions.

Performance of Gibson Golden Delicious on Dwarfing Rootstocks

To evaluate the adaptability and performance of new and promising apple rootstocks in the dwarfing size-control category, a NC-140 regional rootstock trial was established in 2003 at 14 sites in the United States (AR, CA, IA, GA, KY, ME, MI, NY, OH, PA, UT, WI), Canada (BC), and Mexico. The Iowa planting, located at the ISU Horticulture Research Station, includes 23 rootstocks with new selections from the Cornell-Geneva breeding program (G, CG), Russia (Bud), Czech Republic (J-TE), Japan (JM), and Germany (PiAu) with M.26, M.9 Pajam 2, and M.9 T337 serving as industry standards. These rootstocks are being evaluated with Gibson Golden Delicious serving as the test cultivar. This report summarizes the tree-growth and production characteristics through the 2011 growing season.

Black Degradable Plastic Mulch Evaluation

Black polyethylene plastic mulch provides many benefits to fruit and vegetable producers. It increases earliness by increasing spring soil temperatures, conserves soil moisture, and reduces pesticide usage by decreasing weed and disease pressure. Furthermore, during seasons of high precipitation, it protects fertilizer from leaching below the root zone. Unfortunately, polyethylene mulches do not degrade and must be removed from the field and discarded each season. This is a labor-intensive process whether it is done mechanically or by hand. Several degradable plastic mulches have been developed that are designed to be incorporated into the soil profile, eliminating the need for removal, with no negative impact on soil quality or health. However, these degradable plastics often do not meet degradation expectations (either degrade too quickly or degrade incompletely and require manual removal). The objective of this project was to evaluate several degradable mulches for storage life, ease of use, and influence on tomato production.

High Tunnel Bramble Production

In 2006, a study was initiated at the ISU Armstrong Research Farm (ARF) to evaluate the potential for growing high-value floricane and primocane type raspberries and blackberries in a high tunnel. The objectives were to determine if a high tunnel could be used to improve over-wintering of cold sensitive floricane types, and if the harvest season of primocane types could be advanced far enough ahead that they could replace the floricane types in such a production system. A second objective was to determine if these crops could be grown in a high tunnel without pesticides or minimum pesticide usage. This report summarizes the results for the 2009 through 2011growing seasons.

BioCentury Research Farm Update

The BioCentury Research Farm (BCRF) had a diversity of users in 2011. Iowa State faculty and staff from agricultural and biosystems engineering (ABE), agricultural systems technology (AST), agronomy, chemical and biological engineering (CBE), civil, construction, and environmental engineering (CCEE), food science and human nutrition (FSHN), horticulture, mechanical engineering (ME), and natural resource ecology and management (NREM) conducted research, teaching, and outreach at the BCRF. Private industry users included Avello Bioenergy, DCE, Frontline BioEnergy, and Virent, Inc.

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.

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.

Second Year Performance of Honeycrisp on 31 Dwarfing Rootstocks in the Iowa Planting of the NC-140 2010 Regional Apple Rootstock Trial

To evaluate the adaptability and performance of new and promising apple rootstocks in the dwarfing size-control category, a NC-140 regional rootstock trial was established in 2010 at 12 sites in the United States (CO, IA, IL, IN, MA, MI, MN, NJ, NY, OH, UT, WI), two sites in Canada (BC, NS), and one site in Mexico (CHIH) with Honeycrisp serving as the test cultivar. The Iowa planting, located at the ISU Horticulture Research Station, includes 31 rootstocks with new selections from the Cornell-Geneva breeding program (G, CG.), Russia (Bud), Germany (PiAu), and Japan (Supp), with M.26, M.9 Pajam 2, and M.9 T337 serving as industry standards. Tissue cultured propagated (TC) rootstocks of G.41, G.202, and G.935 were included for comparison with normal (N) stool bed propagated rootstocks. This report summarizes the tree-growth characteristics of the Iowa planting during the 2011 growing season.

High Tunnel Production: Inputs, Labor, and Crop Productivity

The 30 × 12 × 96 ft (W × H × L, 2,880 ft 2 ) high tunnel was planted and maintained as part of a high tunnel production budget project funded by a Specialty Crop Grant through the Iowa Department of Agriculture and Land Stewardship. Six growers throughout the state participated in the project with the objectives of creating an enterprise budgeting tool that estimates the costs and revenues associated with producing specific crops in a high tunnel, either as a single crop or multi-crop system. The budgeting tool will estimate the production cost and net profit per square foot in a high tunnel from mono-culture (one crop per tunnel) or multi-cropping, successionplanted systems. This report summarizes the findings from the high tunnel at the ISU Horticulture Research Station. The plantings in this high tunnel were used to collect labor and yield data as well as demonstrate a continuous, multi-cropping production system. A publication containing the enterprise budgeting tool, using this data and data collected from the other six farms, will be available through Iowa State University Extension and Outreach in the fall of 2012.

Enhancing Yield and Biological Nitrogen Fixation of Common Beans

Two studies were conducted at the ISU Horticulture Station to evaluate potential limitations on yield and atmospheric nitrogen fixation by common bean (Phaseolus vulgaris L.). This legume is a food staple for small landholder farm families worldwide. But it has a limited capacity for nitrogen fixation and often yields only a fraction of its genetic potential. In these studies, we examined the dependence of pod filling on current assimilate supply, as well as the potential to improve nitrogen fixation using an inoculant shown to enhance biological nitrogen fixation under stressful conditions.

2010 Home Demonstration Gardens

Themes for the 2010 Home Demonstration Garden Field Days were several newer cultivars of annual flowers (zinnia, four o’clocks, gazania, gaillardia, petunia, coleus, and vinca), a blooming quilt block, eggplant cultivars (including an inedible eggplant), and a compost trial.

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

The Neely-Kinyon 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-S-O/A), organic Corn-Soybean-Oats/Alfalfa-Alfalfa (CS-O/A-A). A new rotation of Corn-SoybeanCorn-Oats/Alfalfa (C-SB-C-O/A) replaced the old S-W/RC rotation.