Yields of relay cropped greens grown in green roof production systems

As interest in urban food production increases, urban farmers are looking for solutions to the challenge of space availability. One solution is to move production to building rooftops, a space that is often underutilized. The use of green roof technology is one method of achieving food production on rooftops; however, there are some additional challenges associated with this practice as a result of the fast-draining, low-nutrient media used. This is particularly challenging for vegetable crops, which typically require more nutrients than the ornamental plants traditionally grown in green roof media. Some rooftop farmers are adding additional organic matter in the form of compost to their beds as an alternative to chemical fertilizers. Currently, there is little research on how rooftop production systems affect crops. Green roof platforms were established at the Harold R. Benson Research and Demonstration Farm in Frankfort, Kentucky, to examine crop yield in green roof systems supplemented with compost. Treatments were a topsoil no compost control, a green roof media no compost control and 3 green roof media treatments: the addition of 0.33, 0.66, or 1 kg m-2 of compost. Organic fertilizers were used to supply additional nutrients to vegetable plants. The crops selected were lettuce, arugula, mizuna, mustard, Swiss chard, kale, and spinach. These were relay cropped in succession during two growing seasons (2018 and 2019). At each harvest, the amount of time harvesting required (in seconds), total yield, and marketable yield (determined by visual examination) were measured for each platform. Yield results were analyzed in R. Analysis of variance was performed on all variables for each crop; compost treatment and year were fixed effects. Significant differences between treatment means were analyzed using Tukey HSD (alpha of 0.05). Results for kale show differences between 2018 and 2019 for harvest time and total yield in the topsoil control, but no differences for marketable yield. These differences are likely due to weather conditions. Kale harvest time, total yield in 2019 but not 2018, and marketable yield were highest in the topsoil control. Harvest time of the topsoil control was not significantly higher than the 1 kg m-2 of compost in green roof media. The marketable yield of the topsoil control was not significantly higher than 0.66 or 1 kg m-2 compost treatments in green roof media. Results for additional crops will also be presented

Evaluating the Effects of Bacillus subtilis Treatment and Planting Depth on Saffron (Crocus sativus L.) Production in a Green Roof System

Given the current urbanization context and rising interest in green roof systems, growing a high-value crop such as saffron crocus in green roof medium could be an opportunity to use the benefits of both the crop and the green roof system; the drainage, aeration, and sand-like texture of green roof media make it suited for saffron production, and the saffron market price could make green roof production commercially viable. Various factors, including plant diseases and planting depth, could affect saffron production. Therefore, this research was conducted to evaluate the effects of planting depth and biofungicide treatments using Bacillus subtilis on saffron production in a green roof system. A completely randomized factorial block design was used with planting depth (10 cm and 15 cm) and B. subtilis strain QST 713 biofungicide treatments (an untreated control, 15.6 × 109 cfu/L, and 31.2 × 109 cfu/L) as independent variables. In 2019, fresh flower yield, fresh stigma yield, and dry stigma yield were calculated during harvesting, and additional data on flower number, tepal length and width, stigma length, and harvest time were collected in 2020. All variables were analyzed using analysis of variance (ANOVA) with planting depth and biofungicide treatments as fixed effects using R. Fresh stigma yield and dry stigma yield were higher in the 10-cm planting depth in 2019. Results were opposite in 2020: flower number, fresh flower yield, fresh stigma yield, dry stigma yield, and harvest time were higher in the 15-cm planting depth than the 10-cm planting depth. B. subtilis treatments did not affect any studied variable in 2020, but in 2019, the higher level of fungicide treatment resulted in lower fresh flower yield and dry stigma yield. There was no effect of biofungicide treatment and planting depth on tepal length, tepal width, and stigma length in both years. This study showed that growing saffron crocus on green roofs is feasible and even resulted in higher yield than field production in many saffron-producing regions and countries. In addition, results indicated that shallow planting might be suitable for annual production, whereas deeper planting could be ideal for perennial production based on the objective. Our findings demonstrated the feasibility of saffron production in the green roof system and suggest further research to develop best management practices

Practices and Barriers to Sustainable Urban Agriculture: A Case Study of Louisville, Kentucky

As urban populations increase, there is growing interest in developing innovative technologies, sustainable urban farming practices, policy measures, and other strategies to address key barriers in urban agriculture that impede improved food security and sustained urban livelihoods. We surveyed forty urban farmers and gardeners (growers) in Louisville, Kentucky, for base-level information to assess their agricultural practices and the various factors or key barriers that could influence such practices. Secondary objectives were identifying areas where practices could be improved, and identifying opportunities for research, outreach, and incentives for urban growers to transition to more sustainable and higher-yielding practices. The majority of these urban growers were white females, were more diverse than Kentucky farmers, and attained a higher degree of education than Kentucky residents as a whole. Most were engaged in urban agriculture for non-commercial reasons, and 11% were full-time urban growers operating farms for profit. Smaller farms were less likely to be operated for profit or have farm certifications than medium-sized or larger farms (Chi-squared = 14.459, p = 0.042). We found no significant differences among farm sizes in terms of whether growers rented or owned the land they were on (Chi-squared = 9.094, p = 0.168). The most common sustainable practices recorded were composting (60%), crop rotation (54%), polyculture (54%), organic farming (49%), and low or no-till (46%). The least common practices were alley cropping (5%), plasticulture (3%), and hydroponics (3%). Small farms were less likely to use crop rotation than medium-sized or large farms (Chi-squared = 13.548, p = 0.003), and farms responding to the survey in the latter part of the data collection were less likely to use compost than expected based on responses from the early part of data collection (Chi-shared = 5.972, p = 0.014). Challenges faced by these growers included limited space, accessibility to farm certification, presence of pests and diseases, and lack of record keeping and soil testing for fertility and contamination. Our study documents the need for more farm certification, education, outreach, training, research, investment, innovative ideas and solutions, collaboration among stakeholders, and better access to land through favorable urban policies and local support

Practices and Barriers to Sustainable Urban Agriculture: A Case Study of Louisville, Kentucky

As urban populations increase, there is growing interest in developing innovative technologies, sustainable urban farming practices, policy measures, and other strategies to address key barriers in urban agriculture that impede improved food security and sustained urban livelihoods. We surveyed forty urban farmers and gardeners (growers) in Louisville, Kentucky, for base-level information to assess their agricultural practices and the various factors or key barriers that could influence such practices. Secondary objectives were identifying areas where practices could be improved, and identifying opportunities for research, outreach, and incentives for urban growers to transition to more sustainable and higher-yielding practices. The majority of these urban growers were white females, were more diverse than Kentucky farmers, and attained a higher degree of education than Kentucky residents as a whole. Most were engaged in urban agriculture for non-commercial reasons, and 11% were full-time urban growers operating farms for profit. Smaller farms were less likely to be operated for profit or have farm certifications than medium-sized or larger farms (Chi-squared = 14.459, p = 0.042). We found no significant differences among farm sizes in terms of whether growers rented or owned the land they were on (Chi-squared = 9.094, p = 0.168). The most common sustainable practices recorded were composting (60%), crop rotation (54%), polyculture (54%), organic farming (49%), and low or no-till (46%). The least common practices were alley cropping (5%), plasticulture (3%), and hydroponics (3%). Small farms were less likely to use crop rotation than medium-sized or large farms (Chi-squared = 13.548, p = 0.003), and farms responding to the survey in the latter part of the data collection were less likely to use compost than expected based on responses from the early part of data collection (Chi-shared = 5.972, p = 0.014). Challenges faced by these growers included limited space, accessibility to farm certification, presence of pests and diseases, and lack of record keeping and soil testing for fertility and contamination. Our study documents the need for more farm certification, education, outreach, training, research, investment, innovative ideas and solutions, collaboration among stakeholders, and better access to land through favorable urban policies and local support