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Because hydroponic operations in the United States can be certified as organic, and because the price of chemical fertilizers has increased, there is an increasing interest in using organic fertilizers and beneficial microorganisms for controlled-environment agriculture. However, there is a scarcity of information regarding their effectiveness and application methodologies. We investigated the effects of inoculating Azospirillum brasilense and Rhizophagus intraradices and using organic fertilizers on growing lettuce (Lactuca sativa ‘Cherokee’) and tomato (Solanum lycopersicum ‘Red Robin’) young plants in an indoor vertical farm. Seeds were sown in rockwool substrate, with A. brasilense (1.05 × 108 colony-forming units⋅L−1) or R. intraradices (580 propagules⋅L−1) applied weekly via subirrigation. Seedlings received chemical fertilizer, organic fertilizer derived from corn steep liquor and fermented fish by-products, and food waste-derived organic fertilizer at 100 ppm total nitrogen every 2 or 3 days. They were grown indoors at 23 °C under light-emitting diode lighting at a photosynthetic photon flux density of 200 μmol⋅m−2⋅s−1 with an 18-hour photoperiod. Lettuce under organic fertilizers had 75% lower shoot fresh mass and 64% less shoot dry mass compared with lettuce under chemical fertilizer. Similarly, tomato seedlings with organic fertilizers had fewer leaves, 75% less shoot fresh mass, and 67% less shoot dry mass. In both lettuce and tomato, the macronutrient and micronutrient concentrations in plant tissues were generally similar regardless of fertilizer treatments, but nitrogen use efficiency and nitrogen uptake efficiency were lower under organic fertilizers compared with those under chemical fertilizer. The inoculation of A. brasilense or R. intraradices showed limited effects on plant nutrient uptake, nutrient concentrations, and seedling growth in both lettuce and tomato. Further research is necessary to optimize application methods for organic fertilizers and beneficial microorganisms to fully harness the benefits of sustainable alternative fertilizers in soilless and hydroponic crop production. [ABSTRACT FROM AUTHOR]

Much research about organic foods standards and certification in the United States employs a critical political economic perspective to interrogate links between certification politics and the "conventionalization" of organic agriculture. While helpful, this literature tends towards a dualistic framework, which emphasizes conflicts between movement-oriented and agribusiness wings of the organic community but obscures deliberative processes that sustain the organic market as an alternative economic space. This article develops a different approach by taking up E. Melanie DuPuis and Sean Gillon's invitation to "begin a conversation about the everyday forms of civic engagement" involved in the governance of the organic foods market and other alternative economies (DuPuis and Gillon in Agric Hum Values 26:43, 2009). I merge DuPuis and Gillon's analysis of civic "modes of governance" in the organic sector with a theory of deliberative discourse developed by the cultural sociologist Jeffrey Alexander. I then apply this approach to examine a 2017 dispute about whether hydroponic growing operations were eligible for certification under the National Organic Program rules. The data indicate that (1) several features of this dispute did not follow the lines of movement/agribusiness conflict emphasized by political economic research and (2) both supporters and opponents of hydroponic certification drew from a common discursive repertoire to advocate for their preferred outcomes. I argue that while this common repertoire does not prevent conflict over the organic standards, it does sustain the importance of civic—as opposed to purely economic or technical—considerations in the sector's governance. [ABSTRACT FROM AUTHOR]

Lettuce (Lactuca sativa L.) is the most common leafy vegetable produced hydroponically in the United States. Although hydroponic systems are advantageous due to lower pest and disease pressure, and reduced water and nutrient requirements, the increasing prices of fertilizers, including phosphorus (P), still influences the profitability of hydroponic production of lettuce. Characterizing lettuce germplasm capable of producing high yield using less P inputs may help reduce fertilizer use, production costs, and P loads in wastewater. In this study, 12 lettuce accessions were grown in four experiments in a nutrient film technique system. In the first two experiments, the treatments consisted of two P concentrations (3.1 and 31 mg·L-1). Lettuce cultivated with 3.1 mg·L-1 of P had variable shoot and root biomass, root-shoot ratio, P uptake efficiency, and P utilization efficiency, indicating the existence of genetic variation. Five accessions ('Little Gem', 60183, 'Valmaine', BG19-0539, and 'Green Lightning') were considered efficient to P because produced similar shoot biomass with the low and high P treatments. In the third and fourth experiments, the treatments consisted of two P sources (monosodium phosphate (NaH2PO4) and tricalcium phosphate [TCP; Ca3(PO4)2]. Initially, extra 5 mM of calcium (Ca) was added to the TCP solution to reduce the TCP solubility and, hence, P bioavailability to plants. All accessions produced similar shoot and root weight with both treatments, indicating that the TCP treatment did not cause low-P stress to the plants. After, the extra Ca concentration added to TCP was increased to 10 mM, resulting in low-P stress and a significant reduction in shoot weight of all accessions. Despite the severe P stress, 'Little Gem' and 60183 were among the accessions with the least shoot weight reduction in the TCP treatment. Variability was observed in root biomass root-shoot ratio among accessions under the TCP treatment, suggesting that lettuce accessions responded differently to P stress conditions. The genetic variation for P use efficiency (PUE) and PUE-related traits in lettuce grown hydroponically suggests the feasibility of breeding new lettuce cultivars from elite lettuce germplasm adapted to low P availability in hydroponics. [ABSTRACT FROM AUTHOR]

Aquaponics is an agricultural practice incorporating aquaculture and hydroponic principles. This study assesses the current system design and production practices of the aquaponic industry, compares these metrics by stakeholder group, identifies trends, and provides recommendations for future development. An electronic survey of aquaponic stakeholders was conducted from December 2019 to June 2020 targeting hobbyists, producers, and educators from various aquaponic-focused professional associations, email and social media groups. Of 378 total responses, 84% came from the United States and were clustered in plant hardiness zones five to nine. Aquaponic systems were commonly homemade/do-it-yourself (DIY), many of which incorporated commercially available (turn-key) technology. Most growers used coupled systems that integrated recirculating aquaculture systems and either deep-water culture (DWC) or media bed hydroponic units. Common plant lighting sources were sunlight and light emitting diode (LED). Water sources were typically municipal or wells. Personal labor input was typically less than 20 hrs/wk. Funding sources were primarily personal funds, followed by government grants, and private investor funds. System sizes varied greatly, but the median area was 50 to 500 ft2 for hobbyists and educators and 500 to 3,000 ft2 for producers. Respondents commonly sold vegetable produce, training and education, food fish, and microgreens. Tilapia and ornamental fish were commonly grown, with 16 other species reported. Common crops were lettuce, leafy greens, basil, tomatoes, peppers, and herbs with many additional lesser-grown crops reported, including cannabis. Overall, the industry still growing, with a large portion of stakeholders having less than two years of experience. However, veteran growers have remained in operation, particularly in the producer and educator groups. The survey results suggest a shift away from outdoor systems, media beds, tomatoes, ornamental fish, and perch production, and a shift toward decoupled systems, DWC, drip irrigation, and wicking beds, larger system area, leafy greens, and trout/salmon production compared to previous industry surveys. The reduced diversity of plant species grown suggest some level of crop standardization. Commercial producers tended to sell more types of products than other stakeholders, suggesting that diversification of offerings may be key to profitability. The combined production area specified by respondents indicates the industry has grown substantially in recent years. Finally, the presence of bank loan-funded operations suggests increased knowledge and comfort with aquaponics among lenders. [ABSTRACT FROM AUTHOR]

This article examined the profitability of aquaponics in the U.S. Midwest. Three sources of data were considered for the study: (1) three active aquaponics farms, (2) a university greenhouse experiment, and (3) published research. The first analysis compares the economics of aquaponics and hydroponics systems under similar operations. Results suggest that the aquaponics system requires higher investment and operating cost but has lower production of vegetables compared with the hydroponics system. However, if aquaponics vegetable production is managed as an organic production, and the produce is sold at 20% premium price, aquaponics becomes profitable. The second analysis constructed three different representative farm sizes of aquaponics production of basil and tilapia—small, medium, and large. The production of basil provides better economic returns than the fish. All farm sizes are feasible when the basil price is above $10.00 per kg. The larger farm has the best results because of lower cost of production. [ABSTRACT FROM AUTHOR]

In 2021, the U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and state partners investigated a multistate outbreak of Salmonella Typhimurium illnesses linked to packaged leafy greens from a controlled environment agriculture (CEA) operation in Illinois. Thirty-one illnesses and four hospitalizations were reported in four states, with a significant epidemiologic signal for packaged leafy greens from Farm A. A traceback investigation for leafy greens included seven points of service (POS) with food exposure data from eight ill people. Each POS was supplied leafy greens by Farm A. FDA investigators observed operations at Farm A and noted that 1) the firm did not consider their indoor hydroponic pond water as agricultural water, 2) condensate dripping from the chiller water supply line inside the building, and 3) unprotected outdoor storage of packaged soilless growth media and pallets used for finished product. FDA collected 25 product, water, and environmental samples from Farm A. The outbreak strain was recovered from a water sample collected from a stormwater drainage basin located on the property adjacent to Farm A. In addition, an isolate of Salmonella Liverpool was recovered from two indoor growing ponds within the same growing house, but no illnesses were linked to the isolate. Farm A voluntarily recalled all implicated products and provided their root cause analysis (RCA) and return-to-market plan to FDA. While the source and route of the contamination were not determined by the RCA, epidemiologic and traceback evidence confirmed the packaged salads consumed by ill persons were produced by Farm A. This was the first investigation of a multistate foodborne illness outbreak associated with leafy greens grown in a CEA operation. This outbreak demonstrated the need for growers using hydroponic methods to review their practices for potential sources and routes of contamination and to reduce food safety risks when identified., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Inc.)

The article presents a study that investigates the vitamin A content of Golden Rice in the U.S. Researchers grew golden rice by means of hydroponics to obtain deuterium-labeled ß-carotene rice grains and cooked 0.99-1.53 milligrams and feed to five health individuals. Moreover, they discovered that the ß-carotene obtained from Golden Rice are converted effectively to vitamin A.

Soybean ( Glycine max Merr.) production is reduced under iron-limiting calcareous soils throughout the upper Midwest regions of the US. Like other dicotyledonous plants, soybean responds to iron-limiting environments by induction of an active proton pump, a ferric iron reductase and an iron transporter. Here we demonstrate that heterologous expression of the Arabidopsis thaliana ferric chelate reductase gene, FRO2, in transgenic soybean significantly enhances Fe+3 reduction in roots and leaves. Root ferric reductase activity was up to tenfold higher in transgenic plants and was not subjected to post-transcriptional regulation. In leaves, reductase activity was threefold higher in the transgenic plants when compared to control. The enhanced ferric reductase activity led to reduced chlorosis, increased chlorophyll concentration and a lessening in biomass loss in the transgenic events between Fe treatments as compared to control plants grown under hydroponics that mimicked Fe-sufficient and Fe-deficient soil environments. However, the data indicate that constitutive FRO2 expression under non-iron stress conditions may lead to a decrease in plant productivity as reflected by reduced biomass accumulation in the transgenic events under non-iron stress conditions. When grown at Fe(III)-EDDHA levels greater than 10 μM, iron concentration in the shoots of transgenic plants was significantly higher than control. The same observation was found in the roots in plants grown at iron levels higher than 32 μM Fe(III)-EDDHA. These results suggest that heterologous expression of an iron chelate reductase in soybean can provide a route to alleviate iron deficiency chlorosis. [ABSTRACT FROM AUTHOR]

Examines the socioeconomic impacts of water farming on rural areas of origin in Arizona. Water farm characteristics; Distribution of employment effects among economic sectors; Estimated economic impacts of retiring agricultural land.

The article focuses on aeroponics, a technology that stemms from the concept of cultivating plants without soil or water. In 1983, Rick Stoner of AgriHouse in Berthoud, Colorado patented a water-conserving, pesticide-free way of growing crops. The article provides stories of individuals who have used the technology. Larry Forrest of Frederick, Colorado owns a 150-square meter aeroponic greenhouse. His company, Grow Anywhere Air-Foods produces tiny seedlings of mesclun and other greens, whose roots are misted with a nitrogen-and calcium-spray for 20 minutes. Edward Hardwood patented an aeroponic system with a cloth conveyer.

The article presents a calendar of events related to the facts and challenges of science for December in the U.S. Hydroponicum was patented on December 1, 1936. Inventor Eli Whitney who is famous for the cotton gin was born on December 8, 1976. On December 10, 2006 cotton gin allows the cotton to be separated from its seeds for easy identification.

Space missions of extended duration are currently hampered by the prohibitive costs of external resupply. To reduce the need for resupply, the National Aeronautics and Space Administration (NASA) is currently testing methods to recycle solid wastes, water, and air. Composting can be an integral part of a biologically based waste treatment/recycling system. Results indicate that leachate from composted plant wastes is not inhibitory to seed germination and contains sufficient inorganic minerals to support plant growth. Other solid wastes, for example kitchen (food) wastes and human solid wastes, can be composted with inedible plant residues to safely reduce the volume of the wastes and levels of microorganisms potentially pathogenic to humans. Finished compost could serve as a medium for plant growth or mushroom production.