scholarly journals Exploitation of Liquid Digestate as the Sole Nutrient Source for Floating Hydroponic Cultivation of Baby Lettuce (Lactuca sativa) in Greenhouses

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7199
Author(s):  
Georgios K. Ntinas ◽  
Filippos Bantis ◽  
Athanasios Koukounaras ◽  
Panagiotis G. Kougias
Keyword(s):  
Nutrient Concentrations ◽  
Mineral Fertilizers ◽  
Growth Media ◽  
Nutrient Source ◽  
Greenhouse Production ◽  
Agronomic Practices ◽  
Liquid Digestate ◽  
Hydroponic Cultivation ◽  
Agronomic Potential ◽  
Leaf Lettuce

Sustainable agriculture relies on replacing fossil-based mineral fertilizers, which are highly cost-energetic to produce, and demand extensive use of scarce natural resources. Today, agronomic practices within the concept of circular economy are emerging and, as such, the exploitation of digestate as a biofertilizer and soil amender is extensively investigated. This study aimed at evaluating the agronomic potential of liquid digestate as the sole nutrient source for hydroponic cultivation of baby lettuce in greenhouses. Growth rate, physiological responses, concentration of secondary metabolites, and nutrient uptake were compared between baby leaf lettuce grown in digestate in concentrations of 5, 10, and 20% diluted in water (either with or without pH adjustment) and in Hoagland solution (control). Results showed that the production yield was negatively correlated with the concentration of the added digestate. Nevertheless, the antioxidant capacity was significantly enhanced in 5 and 10% liquid digestate treatments compared to the control. Additionally, the nutrient composition in the baby leaf lettuce and the reduction in nutrient concentrations in the growth media demonstrated efficient mineral uptake by the plants. Thus, the application of liquid digestate as a fertilizer in hydroponic systems is a promising practice to recover residual resources, leading to the transition towards more sustainable greenhouse production.

scholarly journals The Effect of Environment and Nutrients on Hydroponic Lettuce Yield, Quality, and Phytonutrients

Horticulturae ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 48 ◽  
Author(s):  
William Sublett ◽  
T. Barickman ◽  
Carl Sams
Keyword(s):  
Nutrient Solution ◽  
Growing Season ◽  
Nutrient Concentrations ◽  
Eastern United States ◽  
Marketable Yield ◽  
Greenhouse Production ◽  
Growing Seasons ◽  
Yield And Quality ◽  
Lettuce Yield ◽  
Leaf Lettuce

A study was conducted with green and red-leaf lettuce cultivars grown in a deep-water culture production system. Plants were seeded in rockwool and germinated under greenhouse conditions at 25/20 °C (day/night) for 21 days before transplanting. The experimental design was a randomized complete block with a 2 × 3 factorial arrangement of cultivar and nutrient treatments that consisted of six replications. Treatments consisted of two lettuce genotypes, (1) green (Winter Density) and (2) red (Rhazes), and three nutrient treatments containing electroconductivity (EC) levels of (1) 1.0; (2) 2.0; and (3) 4.0 mS·cm−1. After 50 days, plants were harvested, processed, and analyzed to determine marketable yield, biomass, plant height, stem diameter, phenolics, and elemental nutrient concentrations. An interaction between growing season and lettuce cultivar was the predominant factor influencing yield, biomass, and quality. Nutrient solution EC treatment significantly affected biomass and water content. EC treatments significantly impacted concentrations of 3-O-glucoside and uptake of phosphorous, potassium, iron, boron, zinc, and molybdenum. Effects of growing season and cultivar on leafy lettuce yield and quality were more pronounced than the effect of nutrient solution EC treatment. Thus, greenhouse production of green and red-leaf lettuce cultivars in the south-eastern United States should be conducted in the spring and fall growing seasons with elevated nutrient solution EC of ≈4.0 mS·cm−1 to maximize yield and quality.

scholarly journals Agro-Environmental Sustainability of Anaerobic Digestate Fractions in Intensive Cropping Systems: Insights Regarding the Nitrogen Use Efficiency and Crop Performance

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 745
Author(s):  
Federico Grillo ◽  
Ilaria Piccoli ◽  
Ivan Furlanetto ◽  
Francesca Ragazzi ◽  
Silvia Obber ◽  
...  
Keyword(s):  
Best Management Practices ◽  
Environmental Sustainability ◽  
Inorganic Nitrogen ◽  
Organic Fertilizer ◽  
N Uptake ◽  
Mineral Fertilizers ◽  
Veneto Region ◽  
Liquid Digestate ◽  
Crop Performance ◽  
Use Efficiency

Digestate is an anaerobic digestion by-product rich in inorganic-nitrogen (N) that can be used as an organic fertilizer. Digestate agronomic efficiency and its impact on the environment have not yet been studied in detail, therefore this study tries to fill this gap. The agro-environmental sustainability of digestate fractions was evaluated in a holistic way by comparing the best management practices available in the Veneto Region agroecosystem. A farm experiment involving mineral fertilizer and both liquid and solid digestate fractions was established involving silage winter wheat and silage maize as main crops. Agro-environmental sustainability was investigated coupling crop performance analysis (e.g., yield, N uptake and N use efficiency (NUE)) with a novel proposed agro-environmental sustainability index (AESI) (i.e., product of the dry yield and NUE). The results showed that the liquid digestate fraction gave agronomic performances comparable to mineral fertilizers and a satisfying AESI while solid digestate showed lower performances. In conclusion, liquid digestate fractions might be an effective substitute for mineral fertilizers in the Veneto region agroecosystem reaching encouraging levels of agro-environmental sustainability. On the contrary, longer-term experiments are requested to evaluate solid digestate fraction sustainability.

scholarly journals A Positive Tropism of Rice Roots toward a Nutrient Source

2019 ◽  
Vol 61 (3) ◽  
pp. 546-553
Author(s):  
Kiyoshi Yamazaki ◽  
Yoshihiro Ohmori ◽  
Toru Fujiwara
Keyword(s):  
Cell Elongation ◽  
Lateral Roots ◽  
Fourth Power ◽  
Nutrient Concentrations ◽  
Root Tips ◽  
High Moisture ◽  
Nutrient Source ◽  
Directional Growth ◽  
Rice Roots ◽  
Differential Cell

Abstract Plants take up water and nutrients through roots, and uptake efficiency depends on root behavior. Roots recognize the moisture gradient in the soil and grow toward the direction of high moisture. This phenomenon is called hydrotropism, and it contributes to efficient water uptake. As nutrients in soil are also unevenly distributed, it is beneficial for plants to grow their roots in the direction of increasing nutrient concentrations, but such a phenomenon has not been demonstrated. Here, we describe the directional growth of roots in response to a nutrient gradient. Using our assay system, the gradient of a nitrogen nutrient, NH4+, was sufficient to stimulate positive tropic responses of rice lateral roots. This phenomenon is a tropism of plant roots to nutrients; hence, we propose the name ‘nutritropism’. As well as other tropisms, differential cell elongation was observed before the elongation zone during nutritropism, but the pattern promoting cell elongation preferentially on the non-stimulated side was opposite to those in root hydrotropism and gravitropism. Our evaluation of the NH4+ gradient suggested that the root tips responded to a sub-micromolar difference in NH4+ concentration on both sides of the root. Hydrotropism, gravitropism and phototropism were described in plants as the ‘power of movement’ by Charles and Francis Darwin in 1880, and these three tropisms have attracted the attention of plant scientists for more than 130 years. Our discovery of nutritropism represents the fourth ‘power of movement’ in plants and provides a novel root behavioral property used by plants to acquire nutrients efficiently.

Recycling of domestic wastewater treated by vertical-flow wetlands for watering of vegetables

2015 ◽  
Vol 10 (3) ◽  
pp. 445-464 ◽  
Author(s):  
S. A. A. A. N. Almuktar ◽  
M. Scholz ◽  
R. H. K. Al-Isawi ◽  
A. Sani
Keyword(s):  
Capsicum Annuum ◽  
Tap Water ◽  
Aggregate Size ◽  
Domestic Wastewater ◽  
Sweet Pepper ◽  
Treated Wastewater ◽  
Nutrient Concentrations ◽  
Growth Media ◽  
Vertical Flow ◽  
Untreated Wastewater

The aim was to assess if domestic wastewater treated by different vertical-flow wetlands can be successfully recycled to water commercially grown crops. The growth of both Sweet Pepper (California Wonder; cultivar of Capsicum annuum Linnaeus Grossum Group) and Chilli (De Cayenne; Capsicum annuum (Linnaeus) Longum Group 'De Cayenne') fed with different treated and untreated wastewater types were assessed. The overall growth development of Sweet Peppers was poor due to the high concentrations of nutrients and trace minerals. In contrast, chilies did reasonably well but the growth of foliage was excessive and the harvest was delayed. High yields were associated with tap water and an organic growth medium, and a wetland with a high aggregate size, leaving sufficient space for biomass. Low fruit numbers correlated well with inorganic growth media and irrigation water contaminated by hydrocarbons. Findings indicate that nutrient concentrations supplied to the Chillies by a combination of compost and treated waste water are usually too high to produce a good harvest. However, as the compost is depleted of nutrients after about 8 months, the harvest increased for pots that received pre-treated wastewater. Findings will lead to a better understanding of the effects of different wetland treatment processes.

NUTRIENT DYNAMICS IN EELGRASS (ZOSTERA MARINA) MEADOW AND THE VARIATION OF NUTRIENT CONTENTS OF EELGRASS

2017 ◽  
Author(s):  
Toshimasa Asahi ◽  
Toshimasa Asahi ◽  
Kazuhiko Ichimi ◽  
Kazuhiko Ichimi ◽  
Kuninao Tada ◽  
...  
Keyword(s):  
Water Column ◽  
Pore Water ◽  
Sediment Core ◽  
Zostera Marina ◽  
Nutrient Dynamics ◽  
Similar Rate ◽  
Nutrient Concentrations ◽  
Nutrient Source ◽  
Nutrient Contents ◽  
Seagrass Biomass

Nutrient dynamics in seagrass beds and nutrient demands of seagrass biomass are not clear, although nutrient uptake of seagrass has been experimentally studied in the laboratory. We conducted the field observations and the bottom sediment core incubations to estimate nutrient fluxes in the seagrass, Zostera marina meadow. DIN (nitrate, nitrite and ammonium) concentrations were always low particularly during the Z. marina growing season (from spring to summer), and water exchanges caused by tidal currents hardly supplied nutrient demand for Z. marina. Sediment pore water also supplied insufficient nutrients to Z. marina, because pore water had less volume than the water column, although DIN concentrations of pore water were 10-100 fold higher than those of the water column. Nutrient flux from sediment to water column estimated by the sediment core incubation experiments showed a similar rate with tidal water exchange. Thus, our results suggested that Z. marina adapted for low nutrient concentrations and each nutrient source in the Z. marina meadow slightly contributed but could not support Z. marina growth. We found that another nutrient source, for example, precipitation, supplied high DIN to the Z. marina meadow. After rainfall, the DIN concentration of seawater in the Z. marina meadow increased 2-5 times higher. Moreover, nitrogen content of eelgrass also increased 2-3 times higher during several days. Those results suggested that Z. marina was usually exposed to a low nutrient concentration but could uptake abundant nutrients from temporary nutrient supplies such as precipitation.

scholarly journals Technology for sugarcane agroindustry waste reuse as granulated organomineral fertilizer

2015 ◽  
Vol 35 (1) ◽  
pp. 63-75 ◽  
Author(s):  
MARCÍLIO N. DO A. GURGEL ◽  
SIMONE T. R. CORREA ◽  
DURVAL DOURADO NETO ◽  
DURVAL R. DE PAULA JÚNIOR
Keyword(s):  
Mineral Fertilizer ◽  
High Heat ◽  
Mineral Fertilizers ◽  
Test Plant ◽  
Transfer Coefficients ◽  
Industry Waste ◽  
Waste Reuse ◽  
High Heat Transfer ◽  
Agronomic Potential ◽  
Sugarcane Industry

Aiming to evaluate the use of sugarcane industry waste such as byproducts from vinasse concentration process, it was assessed the organomineral fertilizer BIOFOM (concentrated vinasse, filter cake, boiler ash, soot from chimneys and supplemented with mineral fertilizers). The study included characterization and agronomic potential analysis of a test plant (corn), by noting the differences between mineral fertilizers and BIOFOM fertilization until 45 days after sowing. The technology traditionally used to produce BIOFOM was based on vinasse evaporation with high heat transfer coefficients. It was observed that the technology, which can be formulated according to the needs of any crop, could be used in many cases as mineral fertilizer. Therefore, the use of this organomineral fertilizer reduces waste generation of sugarcane industry.

scholarly journals Effect of N:K Ratio and Electrical Conductivity of Nutrient Solution on Growth and Yield of Hydroponically Grown Golden Thistle (Scolymus hispanicus L.)

Proceedings ◽  
2020 ◽  
Vol 30 (1) ◽  
pp. 87
Author(s):  
Dimitrios Papadimitriou ◽  
Emmanouil Kontaxakis ◽  
Ioannis Daliakopoulos ◽  
Thrassyvoulos Manios ◽  
Dimitrios Savvas
Keyword(s):  
Electrical Conductivity ◽  
Nutrient Solution ◽  
Chlorophyll Concentration ◽  
Tuberous Root ◽  
Growth And Yield ◽  
Nutrient Concentrations ◽  
Fresh Weight ◽  
Natural Habitats ◽  
High Quality ◽  
Hydroponic Cultivation

As the demand for high-quality wild greens rises, due to their high nutritional, culinary, and medicinal properties, the potential overexploitation and excessive disruption of their natural habitats bring serious environmental problems to the foreground. However, new alternative cultivation techniques, such as hydroponic cultivation, could take advantage of rational water management, optimal fertilization management and climate adaptation, to produce high-quality wild greens, all year round. As an initial step to assess optimal hydroponic cultivation conditions for golden thistle (Scolymus hispanicus L.), in this study we evaluated the effect of N:K ratio and electrical conductivity (EC) in the supplied nutrient solution on plant growth, yield and phenology. Four nutrient solutions were applied with a low or a high N:K ratio (1.59 or 2.38 mol/mol, respectively) combined with a low or a high electrical conductivity (EC) level (2.2 and 2.8 dS m−1, respectively) in a 2 × 2 factorial experiment set as a completely randomized block design with 4 blocks and 48 plants per block. Golden thistle seedlings were planted in plastic growth-bags of hydroponic perlite substrate in an open, drip-irrigated, soilless cultivation system. The experiment commenced in December 2018, in a plastic greenhouse at the campus of the Hellenic Mediterranean University, Crete, Greece. After four months of cultivation, the post-harvest analysis showed that the high N:K ratio significantly increased the fresh weight of leaf and edible tuberous root, whereas the tested EC levels in the nutrient solution had no impact on plant fresh weight. The experimental treatments did not significantly affect leaf chlorophyll concentration (SPAD meter readings), chlorophyll fluorescence (Fv/Fm) or the number of leaves and the specific weight of the tuberous root of the plants. Our results indicate that wild golden thistle could be domesticated as an edible vegetable, and cultivated hydroponically at different seasons of the year using relatively low nutrient concentrations, thereby minimizing aquifer nitrate and phosphate pollution. A nutrient solution with a relatively high N:K ratio (here 2.38 mol/mol) is recommended for the hydroponic cultivation of golden thistle.

Pesticide runoff from greenhouse production

2010 ◽  
Vol 61 (6) ◽  
pp. 1373-1381 ◽  
Author(s):  
Roger Roseth ◽  
Ketil haarstad
Keyword(s):  
Agricultural Runoff ◽  
Pine Bark ◽  
Nutrient Concentrations ◽  
Sphagnum Moss ◽  
Column Experiments ◽  
Greenhouse Production ◽  
Risk Levels ◽  
Filter Materials ◽  
Oat Straw ◽  
Pesticide Runoff

A research has been undertaken studying pesticide residues in water from greenhouses and the use of soils and filter materials to reduce such losses. The pesticides detected in water samples collected downstream greenhouses include 9 fungicides, 5 herbicides and 4 insecticides. 10 compounds from flower and vegetable productions were frequently found to exceed environmental risk levels, and with a few exceptions the compounds were found in higher concentrations than those typically found in agricultural runoff. Some compounds were found in high concentrations (>1 μg/l) in undiluted runoff from greenhouses producing vegetables. Nutrient concentrations in the runoff were also sporadically very high, with phosphorous values varying between 0.85 and 7.4 mg P/l, and nitrogen values between 7.5 and 41.4 mg N/l. Undiluted runoff from the productions showed values of 60 mg P/l and 300 mg N/l. High values of pesticides correlated with high values of nutrients, especially P. Column experiments using a sandy agricultural soil and stock solutions of non-polar and slightly polar pesticides mixed with a complex binder and nutrients showed a significant reduction for nearly all of the compounds used, indicating that transport through soil will reduce the concentrations of the studied pesticides. The pesticide adsorption capacity of the filter materials pine bark, peat, Sphagnum moss, compost, oat straw, ferrous sand and clay soil were tested in batch and column experiments. Adsorption were studied contacting the filter materials with aqueous solutions containing greenhouse production pesticides. The batch experiments showed that pine bark and peat, both combining a high content of organic matter with a low ph, provided the highest adsorption for most of the tested pesticides. Sphagnum moss, compost and oat straw also showed high adsorption for most of the pesticides, while the mineral filters provided the lowest adsorption (30–55%). Further column experiments confirmed these results, displaying the best removal efficiency in the organic materials, varying from 200 μg/g in compost, to 500 μg/g in moss, straw and pine bark.

scholarly journals Nutrient Concentrations in Field-grown Lettuce Leaves and Roots

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 795C-795
Author(s):  
Zhongchun Jiang*
Keyword(s):  
Organic Fertilizer ◽  
Weather Conditions ◽  
Nutrient Concentrations ◽  
Soil Conditions ◽  
Fertility Level ◽  
N Concentration ◽  
Leaf Tissues ◽  
Leaf N Concentration ◽  
Root Tissues ◽  
Leaf Lettuce

Nutrient concentrations in lettuce leaves are an important factor that affects lettuce quality, particularly the nutritional value of lettuce. When lettuce is grown hydroponically, tissue nutrient concentrations may be regulated through adjustments of the nutrients in the solution in which the lettuce is grown. However, when lettuce is grown in the field, the levels of tissue nutrients can be affected by many factors, such as soil conditions, fertilizer applications, and weather conditions. The objective of this study was to ascertain the variability of leaf and root tissue nutrients in loose-leaf lettuce grown in the field. An organic fertilizer that had an analysis of 4-6-6 as well as 3% Ca, 0.5% Mg, and 5% S derived from dehydrated manure, crab meal, cocoa meal, and other materials was applied at the time of planting and also side dressed after planting. There were significant differences in the concentrations of some elements between leaf tissues and root tissues. Leaf K, Ca, and Mg concentrations were significantly higher than those in the roots while leaf P concentration was lower than that in the roots. Leaf N concentration was similar to root N concentration. Micronutrients, such as Fe, MN Cu, Zn, and Mo, had lower concentrations in the leaves than in the roots. Leaf B concentration was similar to that in the roots. In addition, leaves accumulated lower concentrations of Al and Na than did the roots. No significant differences in the concentrations of these elements were observed between the fertilized plots and the unfertilized plots, which suggested that the field might have a sufficient fertility level and/or that the organic fertilizer might be slow in releasing its nutrients for the lettuce.

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