In a two-part study, we examined the effect of sowing date and harvest schedule on the yield of spinach (Spinacia oleracea) grown during the winter in 16 × 32-ft-high tunnels in northern New Mexico. Each part of the study was conducted for two growing seasons and took place between 2012 and 2015. In Study A (2012–13 and 2013–14), spinach was sown four times at roughly 2-week intervals (mid-October, early November, mid-November, and early December) and plant density (plants per square foot), plant height (centimeters), and yield (grams per square foot) were measured for three harvests in mid-January, mid-February, and mid-March. The earliest sowing date had the least-dense stands, and plant density increased with each subsequent sowing. The two earliest sowing dates had significantly higher season-long yield than the later two sowings. In Study B (2013–14 and 2014–15), all plots were sown in mid-October, but harvest schedule treatments were staggered such that harvests began at 9, 11, 13, or 15 weeks after sowing and continued at irregular intervals. Treatment 2, with harvests beginning after 11 weeks, had the greatest season-long yield, slightly greater than when harvests began at 9 weeks, and significantly more than when harvest began 13 weeks or later. More importantly, a staggered harvest schedule can provide spinach weekly for direct marketing opportunities.
Robert F. Heyduck, Steven J. Guldan and Ivette Guzmán
Zachary N. Hoppenstedt, Jason J. Griffin, Eleni D. Pliakoni and Cary L. Rivard
Sweetpotatoes (Ipomoea batatas) are nutritious, easily stored, and well adapted to a variety of organic farming operations. This widely consumed root crop is propagated through the use of cuttings, known as slips. Slips are commercially grown primarily in the southeastern United States, and growers in the central United States still have limited access to sweetpotato planting material. Production of organic slips in high tunnels (HTs) could be a profitable enterprise for growers in the central United States given the season extension afforded by controlled-environment agriculture, which could allow growers to diversify their operations and facilitate crop rotation. In trials conducted in 2016 and 2017 at two research stations in northeast and south central Kansas, a systems comparison was used to evaluate the yield and performance of organic sweetpotato slips grown in HT as compared with the open field (OF), with four to six replications at each location. Propagation beds planted with ‘Beauregard’ seed roots in 2016 and ‘Orleans’ in 2017 were established in HT and OF under similar cultural methods and planting schedules. Slips were harvested from both treatment groups and transplanted to field plots to investigate the impact of production system on transplant establishment and storage root production. Slip yield from HT was greater than OF at both locations in 2016 (P ≤ 0.001), but this trend was inconsistent in 2017. Slips grown in HT were on average 12% less compact (slip dry weight per centimeter length) with fewer nodes than their OF counterparts in 2016. Nonetheless, mean comparisons for vine length, stem diameter, and total marketable storage root yield were not significant between HT and OF treatments (1.7 and 2.1 lb/plant, respectively). Similarly, the number of marketable storage roots for HT and OF groups was comparable (3.4 and 3.8 storage roots/plant, respectively). Although more research is needed to evaluate the feasibility of slips grown in HT and to determine recommendations for seed root planting densities, results from this study suggest that HT organic sweetpotato slip production could be a viable alternative to OF production as it relates to slip performance. According to this study, HT production could be a useful mechanism for growing sweetpotato slips, which could provide regional growers more control over planting material. Furthermore, HT slip production could promote the adoption of an underused vegetable crop that can be grown throughout many parts of the United States.
Zhi Quan, Bin Huang, Caiyan Lu, Yi Shi, Yanhong Cao, Yongzhuang Wang, Chuanrui He, Guangyu Chi, Jian Ma and Xin Chen
, R. He, X. 2010 Higher rates of nitrogen fertilization decrease soil enzyme activities, microbial functional diversity and nitrification capacity in a Chinese polytunnel greenhouse vegetable land Plant Soil 337 137 150 Shi, W. Yao, J. Yan, F. 2008
Mary Woodhead, Ailsa Weir, Kay Smith, Susan McCallum, Katrin MacKenzie and Julie Graham
locations with two open-field sites and one under protection (polytunnel), in randomized complete block trials with three replicates and two plant plots at all locations. DNA was isolated from the parents and 188 progeny ( Graham et al., 2003
Matt A. Rudisill, Bruce P. Bordelon, Ronald F. Turco and Lori A. Hoagland
growing season for increased crop productivity. High tunnels, or polytunnels, are structures covered by a single or double layer of polyethylene and are usually passively ventilated. They create a more controlled growing environment by offering protection
Samuel J. Dunlop, Marta Camps Arbestain, Peter A. Bishop and Jason J. Wargent
Food producers currently face considerable financial challenges related to rising energy and input costs. In particular, those foodstuffs produced indoors under glass, or in other protected environments (e.g., polytunnels) accounts for more than 650