Photosynthetically active radiation and root-zone temperature effects on high-tunnel primocane red raspberry growth and development

High-tunnel primocane red raspberry production is beneficial in the North Central Region of the United States where production is dependent upon the length of the growing season. Advantages of growing Rubus iadaeus L. (red raspberries) in high-tunnels include improved climatic conditions, reduced winter-cane injury, decreased disease incidence, improved berry size and quality, advanced fruit maturation and harvest, and a 50% extension of the harvest season. Improved climatic conditions of high-tunnels also have affected primocane red raspberry growth and production negatively, by reducing shoot growth, fruiting lateral development, yield, and berry quality, due to increased PAR and air- and root-zone temperature in high-tunnel systems. With the expansion of high-tunnel primocane red raspberry production in an area with seasonal climatic extremes, such as the North Central Region, there is a need for simple management practices for tunnel environment manipulation. The primary objective of this study was to evaluate the relationship between temperature and irradiance (photosynthetically active radiation, PAR) and their effect on primocane growth, development, and production. Sub-objectives of this investigation were to evaluate the efficacy of shadecloth in reducing PAR and air-and root-zone temperature during high-tunnel primocane red raspberry production, and the potential of soil mulch in reducing temperature of high-tunnel primocane red raspberry at the root-zone depth. The influences of PAR and root-zone temperature on vegetative and flowering growth responses of primocane red raspberry `Autumn Britten\u27 were examined. Dormant, one-year-old crowns were planted in 2012, under three identical polyethylene-covered tunnels and in a field plot. A split-plot, randomized complete block design was used. Light transmission through the tunnel polyethylene cover was reduced by 17% before treatments were applied. Whole plot target PAR reduction of 50% was achieved with the addition of shadecloth with a 33% shade factor. In both production years, shadecloth was applied in early June and removed when mean PAR fell below 600 micromole·m-2·s-1 in late September. At planting, crowns were either mulched with Panicum virgatum L. (switchgrass) mulch groundcover or grown with no mulch. The combination of the shadecloth and the polyethylene-cover reduced mean tunnel PAR by an average of 49% in the two years of the experiment. Seasonal climatic extremes provided no differences in treatment temperature at the height of cane growing point. Root-zone temperature had a greater effect on primocane growth, cane architecture, and yield components compared to air temperature or PAR. Root-zone temperature was consistently greater in tunnels without shadecloth or nonliving mulch. The combination of reduced PAR from the 33% shadecloth and the presence of the nonliving mulch provided the greatest reduction of temperature at primocane raspberry root-zone depth, and optimized cane height and adventitious lateral count before terminal bud formation. A positive correlation between flower lateral length and number of flowers produced per lateral was found at root-zone temperatures most similar to the field. Similar associations of increased cane density, leaf area and count, and flower lateral count were found with root-zone temperature most similar to the field. Establishment year decreased fall root-zone temperature, as a result of shadecloth or soil mulch, increased cane density and shoot growth the subsequent spring. Root-zone temperature was the most influential climatic parameter, accounting for 71% of yield variability among treatments in year two, followed by PAR (29%), and air temperature (0%). Primocane yield in high-tunnels was optimized by maintaining root-zone temperature in the low to mid 20 °C range. Fresh berry weight was not influenced by differential PAR and root-zone temperature. Differential climatic conditions of air- and root-zone temperature and PAR did not influence the timing of bud initiation, though time-to-ripening was delayed a result of shading and root-zone temperature up to 23 °C. Sugar content of field-grown red raspberries increased as the season progressed, but soluble solids concentration decreased with the advancement of the harvest season in tunnels. It is beneficial to manipulate the tunnel root-zone temperatures between flower-bud developmental stages of petal fall and first harvest. For high-tunnel primocane red raspberry production in the North Central Region, optimizing root-zone temperature favors the vegetative to flowering transition, and increases yield as a result of increased cane density, fruiting lateral count and length, and quantity of flowers produced per lateral. Basic manipulation techniques such as applying a nonliving mulch groundcover or obtaining a target PAR reduction of 50% can optimize primocane red raspberry growth of tunnel environments in the North Central Region of the United States

Companion Planting: A Method for Sustainable Pest Control

For centuries, companion planting has been practiced by many tribal groups throughout the world. Three Sisters is one example of companion planting known to Native American tribes. Corn, beans, and squash are grown together, providing high yielding, high-quality crops with a minimal environmental impact. Companion planting has taken a growing interest among today’s conventional farmers

Pest Damage Effects: Evaluating the Benefits of Perimeter Trap Cropping and Row Intercropping

Trap cropping is the planting of a trap crop to protect the main crop from a pest, by having the trap crop appear more attractive to the pest than the main crop. There are two forms of trap cropping; perimeter trap cropping (PTC), also known as border trap cropping, and row intercropping. Perimeter trap crops completely surround the main crop, preventing an attack from any direction. Row intercrops are planted in alternating rows with the main crop. While PTC and row intercropping can be useful methods in pest control, they may not alleviate a problem completely, but provide a sustainable way to monitor and control target pests

Horticulture Enterprise Management (Hort/Ag EdS 465)–Year Review

Originally introduced in the spring of 2011, the cross-listed Hort/Ag EdS 465 course was reintroduced Spring 2014 to the horticulture curriculum at Iowa State University. Modeled after the Ag 450 farm, the purpose of Hort/Ag EdS 465 is to provide students with the experience in managing a horticultural farm and to engage students in active learning of running a horticulture enterprise

Photosynthetically Active Radiation and Root-zone Temperature Effects on High Tunnel Primocane Red Raspberry Development

Climatic conditions found in high tunnels of the Upper Midwest have shown adverse effects to primocane red raspberry growth and development. Photosynthetically active radiation (PAR) greater than 600 µmol·mˉ2sˉ1 has been found to decrease shoot growth, fruit quality and yield, and contribute to the onset of premature bud dormancy. Researchers also found as air- and root-zone temperatures exceed 75°F and 60°F, respectively, reduced yield, berry weight, and berry quality may result. The proposed study was intended to conclude results taken from 2012 and 2013, with an additional year of data taken on fully established canes in 2014. Our objectives were to 1) assess the relationship between PAR and temperature and their effect on primocane development, and 2) evaluate the efficacy of shade cloth and soil mulch in reducing PAR and root-zone temperature during high tunnel primocane red raspberry production

The Effects of Temperature and Light in High Tunnel Primocane Red Raspberry Production—Year 2

Climatic factors found in tunnels of the Midwest may show negative effects to primocane growth and development of raspberry. Researchers have found that as air and root-zone temperature exceed 24°C (75.2°F) and 16°C (60.8°F), respectively, the following plant development occurs: decrease in water uptake by primocanes, premature dormancy of lateral and axillary buds, delayed time to fruit ripening, and reduced fruit quality and weight. In addition to temperature, high light (irradiance) causes a decline of fruit yield and quality. Premature dormancy and delayed time-to-flowering occur when irradiance exceed 600 μmol·mˉÇsˉÅ. The proposed study was intended to (1) assess the relationship between temperature and light intensity and their effect on primocane growth and development, (2) evaluate how effective shade cloth and soil mulch are in reducing temperature and light intensity levels of high tunnel red raspberry production, and (3) provide relatively inexpensive solutions to minimize temperature and light intensity damage in protected red raspberry production during the warm summer months

High Tunnel Tulip Production

High tunnels are unheated plastic-covered structures used in the horticulture industry to advance or extend the harvest season of high value crops. In Iowa, these polyethylenecovered structures provide a level of environmental protection between a heated greenhouse and open field production. Without supplemental heat, high tunnels in Iowa will not support annual crop growth and production between November and April, thus most high tunnels are not used during this cold season. In late October 2008, a study was initiated at the ISU Armstrong Research Farm to evaluate the potential of growing tulips as a cut flower crop to fill in this production gap and provide for year-round production in an unheated Iowa high tunnel. A second objective of the study was to control tulip bloom time in a high tunnel through variety selection, planting depth, and row covers

Cold Hardy Wine Grape Cultivar Trial

In conjunction with the Northeast Regional Research project NE 1020 “Multi-state Evaluation of Wine Grape Cultivars and Clones,” Iowa State University established a cold hardy wine grape cultivar trial in 2008 at the ISU Horticulture Research Station (HRS) and Tabor Home Vineyards and Winery (THV) near Baldwin, IA. The Iowa trial evaluates the performance of Corot noir, La Crescent, Marquette, Petit AmiTM, NY 95.0301-01, MN-1189, MN-1200, MN-1220, MN-1235, MN-1258 with Frontenac, and St. Croix serving as controls. This report summarizes the results for the 2012 growing season

High Tunnel Greek Oregano Production in 2008

This report on Greek Oregano\u27s potential as an Iowa niche crop was originally published in the 2008 Annual Progress Reports for the Horticulture Research Station (ISRF 0008-36)

NE-1020 Cold Hardy Wine Grape Cultivar Trial

In conjunction with the Northeast Regional Research project NE-1020 “Multi-state Evaluation of Wine Grape Cultivars and Clones,” Iowa State University established a cold hardy wine grape cultivar trial in 2008 at the ISU Horticulture Research Station (HRS), Ames, Iowa, and Tabor Home Vineyards and Winery (THV), Baldwin, Iowa. The Iowa trial evaluates the performance of Corot noir, La Crescent, Marquette, Petit Ami™, NY95.0301- 01 (Arandell), MN1189, MN1200, MN1220, MN1235, MN1258, with Frontenac and St. Croix serving as controls. Selection NY95.0300-01 was shipped by mistake and was planted in the guard rows and as end-ofrow guard vines. This report summarizes the results for the 2013 growing season