Development of highly productive protected cultivation of tomato in Southern U.S.

The study will be performed at two locations in Centra Oklahoma and the RGV in South Texas. High tunnel studies will be performed in high tunnels available at Langston University, OK, and Texas A&M AgriLife Research and Extension Center, Weslaco, TX. High tunnel located at the Horticulture Education Research and Extension Center (HERC), LU, in Langston, Oklahoma (measuring 96' x 33' x 10') will be used.  In Texas A&M AgriLife, Weslaco, available ~2,000 ft² high-tunnel structures covered with a single polythene film roof (6 mil poly cover) and a drop-down curtain (6 mil poly cover) sidewall system to passively control temperature. The sides of the structure are also covered with 50-mesh screen to reduce insect pressure. In both locations, available greenhouses will be used for raising the tomato seedlings for transplanting. Planting dates and cultivar evaluation will be performed simultaneously by location to determine best production practices.

Objective 1:

Tomatoes will be planted in high tunnel during spring season in Oklahoma and winter at South Texas. Six tomato cultivars including beefsteak, and cherry type will be evaluated. Commercial checks and specialty tomato cultivars developed by tomato breeding program at Texas A&M will be included in both locations. Seedlings will be grown in greenhouses and transplanted after ~5 weeks in the second week of October in Texas, and in second week of March in Oklahoma. Cultivars will be replicaed four times in Randomized Complete Block Design (RCBD).

Maintaining optimal environmental conditions within the high tunnel will be a priority throughout the growth cycle. Weather stations placed within the structure will monitor temperature and humidity levels. If external temperatures are predicted to fall below 50°F, all side walls will be closed to control temperature. During transplanting and early crop establishment in spring in Oklahoma, if external temperatures are anticipated to drop below 44°F, supplementary heating will be implemented. When outdoor temperatures are within the above mentioned threshold temperatures, high tunnel rollup side walls will be opened for aeration. To mitigate the temperature build up inside the tunnel during summer months in Oklahoma, in first week of May, roof of the high tunnel will be covered with black-colored 25% shade cloth. During period of rainfall and high wind conditions, side walls will be closed to minimize the effect of those factors to the plants inside the high tunnel.

In order to optimize production, inputs such as mulching, water-use efficiency, fertigation, and management of insect pests and disease will be adopted as needed. Moisture level in the plots will be sensed through watermark® sensors (Irrometer company, CA). Sensor probes will be used to sense moisture from 6”, 12”, 18” and 24” depth of soil. Sensors data will be recorded using Watermark datalogger (Irrometer company, CA). Average of the sensors reading will be used to initiate the irrigation, and irrigation will be provided if moisture sensed in watermark® sensor shows >20 centibar (cBars). Marketable and non-marketable tomato fruit yield, fruit quality traits (brix, acidity, color, and firmness), and earliness (days to harvest) will be measured to determine best planting dates. Fruit cracking, blossom end rot, sunscald, yellow shoulder, cat-facing, zippering, and insect and disease infestation etc., will be considered as non-marketable fruits.

In 2^nd and 3^rd year, three growers (cooperating farmers) evaluate the tomato production performance under the high tunnel in their farms.

To compare the high tunnel production method with the open field, open field study will also be performed. Greenhouse raised ~5 weeks tomato seedlings will be transplanted in fourth week of April in Oklahoma. In Texas A&M AgriLife, Weslaco, transplanting will be performed 1st week of March. The same six cultivars that would be used for high tunnel evaluation will be evaluated in field studies too. All the production practices and management will be mirrored with the high tunnel system. 

Data analysis: Data from both high tunnel studies would be subjected to mixed model in R. In high tunnel study, cultivars will be the main factors. Data from different locations i.e., HERC at Langston University, Texas A&M AgriLife-Weslaco, and Farmers own evaluations will be analzyed separately. Treatment means will be separated using Tukey’s multiple comparison test using “agricolae” package in R.

Objective 2:

In this study, micro-tunnel will be used to evaluate the early planting of tomato in spring season. Seedlings will be raised in greenhouse for 5 weeks. In Oklahoma, February 28, March 15, March 30, and regular open field in third week of April will be evaluated. For micro-tunnel studies in Texas, three early transplanting dates January 15^th, 30^th and February 15^th and regular open field on first week of march will be evaluated to determine the optimal planting dates. Regular open field planting will serve as control to compare the performance of tomato production under micro-tunnels. Micro-tunnel will be removed in fourth week of March in Texas, and in 1st of May in Oklahoma trials. In both high tunnel and micro-tunnel studies, six tomato cultivars including beefsteak, and cherry type will be evaluated. Tomato cultivars will be replicated four times in RCBD. Variables such as yield, and quality fruit characteristics such as total soluble solid, fruit acidity, color, size, earliness, and firmness will be measured. Similar management practices as mentioned in Objective 1 will be performed. Tomato yield, fruit quality traits (brix, acidity, color, and firmness), and earliness (days to harvest) described in objective 1 will be measured to determine best planting dates. Environmental variables including air and soil temperature, solar radiation will be measured to correlate them to grow and cultivar performance by date.

In 2^nd and 3^rd year,  one grower will evaluate the tomato performance  in micro-tunnel conditions in their farms using the best two planting dates from year 1 at experimental fields.

Data analysis: Micro-tunnel studies would be subjected to mixed model in R. Cultivars, planting times, and interaction of cultivars with the planting times will be the main factors. Research data from HERC center at LU, Texas A&M AgriLife, and farmers field will be analyzed separately. Treatment means will be separated using Tukey’s multiple comparison test using “agricolae” package in R.

Objective 3:

To guarantee a broad adoption of high tunnel and micro-tunnel production systems by small- to mid-scale vegetable growers, it is imperative to assess their economic feasibility.

The economic analysis will involve the creation of distinct standard enterprise budgets, aimed at facilitating a comprehensive comparison of cost and returns associated with tomato production in high tunnel, micro-tunnel versus open field systems. This approach aligns with established precedent as evidenced by previous studies (Chase 2023; Ernst 2020; KSU 2022). Production data, as earlier outlined, will be systematically collected from the aforementioned experimental fields. To ensure methodological consistency in the comparison of production systems, a uniform set of prices and costs will be applied across the budgets.

The computation of the budget analysis will incorporate various production variables, including fertilizers, drip lines and irrigation fittings, pesticides, irrigation, repairs, maintenance, and miscellaneous supplies. Labor costs will be determined based on the annual salaries reported by vegetable farm owners in Oklahoma, and in South Texas. To align with established practices, the cost depreciation process will be conducted in high tunnel using straight-line depreciation spread over a 10-year timeframe, in accordance with the guidelines stipulated by the Internal Revenue Service's Farmer's Tax Guide. This guide designates a 10-year recovery period for horticultural structures within the General Depreciation System (Internal Revenue Service, 2011). The resulting annual depreciation cost will be prorated by either two or three to accurately reflect the 4-month or 6-month seasons under scrutiny within this study. This adjustment is pivotal for precise assessment of costs and revenues, especially during the winter production phase.

In addition, sensitivity analyses will be executed to assess the economic implications of reducing market prices for specific items by 25%, 50%, and 75% of their established base sales price. By exploring these scenarios, the study aims to provide a more nuanced understanding of the potential impact of market fluctuations. Moreover, the analytical framework will incorporate partial budgeting techniques and probabilistic modeling. These sophisticated methodologies serve to address both production and market uncertainties. By engaging in this comprehensive approach, the study seeks to illuminate the cost-benefit dynamics associated with the commercial-scale tomato production across different systems. The outcome of these analyses will manifest as probability distribution functions, which in turn will facilitate an assessment of the likelihood of economic success—specifically, the probability of achieving a positive net return—within the context of tomato production under the tunnels system. This evaluation will factor in anticipated market conditions and contribute to a more holistic understanding of the economic landscape production inputs including supplies, labor, irrigation, agrochemical applications, harvesting, etc. will be recorded for production cost determination for each production system and planting date. Multi-season production data from experimental trials in combination with secondary market information (i.e., prices, demand trends, etc.) will be used to conduct economic cost-benefit analysis of the production of tomato in high tunnel and/or micro-tunnels system.

Objective 4:

To disseminate the cost-effective protected tomato production technology and the best management practices developed at the Horticulture Education Research and Extension Center (HERC) at Langston University and Texas A&M AgriLife-Weslaco, dedicated field day events will be organized. The purpose of this event is to showcase the practical adoption of the developed tunnels technology to attain maximum benefits in tomato cultivation. During these informative field days, all research findings and insights will be presented comprehensively. The field day program hosted at HERC, Langston University, and Texas A&M AgriLife will span a duration of 3 to 4 hours. A targeted audience of approximately 70 growers from diverse regions of Oklahoma, including Oklahoma City, Tulsa, and the Muscogee Nation of Oklahoma, will be extended invitations to participate in this impactful demonstration. Similarly, in South Texas, vegetable growers from the Rio Grande Valley will be invited for field demonstrations. Growers will have the opportunity to directly witness and comprehend the distinctions between high tunnel, micro-tunnel, and open field tomato production methods. Similarly, participants will have the opportunity to visit the tomato trials performed at cooperating farmers owned high tunnel, and micro-tunnel conditions. Cooperating farmers performing tomato trials in tunnels in this project will demonstrate their tomato trial and explain to the attendees. These all activities will help to disseminate the technology and help the growers in decision making process.

In addition to demonstrate production practices and expected yields, the economic feasibility analysis will be disseminated and discussed as a decision tool to promote protected tomato production. Furthermore, results will be published in extension bulletins, newsletter, peer reviewed articles, university websites, and presentations at conference meetings.