Soilless Production Research Articles

Assessing the Potential Use of Drainage from Open Soilless Production Systems: A Case Study from an Agronomic and Ecotoxicological Perspective

Assessing the Potential Use of Drainage from Open Soilless Production Systems: A Case Study from an Agronomic and Ecotoxicological Perspective

Kale (Brassica oleraceaL. var acephala) production in soilless systems in the Mediterranean region

The challenges faced by traditional agriculture led to the development of alternative agricultural systems such as soilless systems. This work aimed to assess the growth and yield components of kale under three soilless growing systems: Nutrient film technique set up vertically (T-vertical); Nutrient film technique set up horizontally (T-horizontal), and substrate coco bags (T-coco). The trials were conducted for two consecutive growing seasons (S1: Spring 2018 and S2: Fall 2019) in an unheated greenhouse. Irrigation supply, maximum plant uptake of water, and radiation use efficiency were evaluated for both seasons. The quantitative and qualitative parameters of the production were assessed in terms of yield ( kg per plant and kg per m²), number of leaves per plant, dry matter, protein content, nitrate level and leaf mineral composition. The main results showed that the maximum plant uptake was 0.30, 0.30 and 0.20 L m^-2 day^-1 respectively for T-vertical, T-horizontal and T-coco while the actual supply of water was 62.4, 32.28 and 3.27 L m^-2 day^-1, respectively. A significant difference was recorded for the number of leaves, yield components, dry matter, protein level, Radiation Use Efficiency and mineral composition of kale leaves was higher during fall than in the spring season. However, the nitrates level was much higher in spring than in fall. The T-vertical soilless system showed better yield (6.83±2.27 kg per m²), more proteins (2.53±0.31 g per100 g FW), and higher amounts of calcium (Ca), total nitrogen (N), manganese (Mn), and iron (Fe) than the other systems. The study demonstrated the potential of soilless production technologies in the coastal Mediterranean areas.

Application of Directly Brewed Compost Extract Improves Yield and Quality in Baby Leaf Lettuce Grown Hydroponically

The aim of this work was to study whether the application of a directly brewed compost extract (added in the nutrient solution or by microsprinkler) could be used to improve the yield and quality of baby leaf red lettuce growing in a floating system, and to control the incidence of Pythium irregulare. Its effect on the quality of fresh-cut red lettuce was also studied. For this, two experiments were carried out over two growing cycles (winter–spring and autumn). The results showed that the use of compost extract added to the nutrient solution improved baby leaf lettuce growth and quality, reducing the nitrate content and enhancing the content of potentially health-promoting compounds such as phenols and flavonoids and the antioxidant capacity. Microbial quality was maintained during storage and the compost extract had no negative effect on the microbial load of the final product. In addition, application of the compost decreased the population of P. irregulare in the water. It is concluded that the application of directly brewed compost extract is of potential use in a sustainable soilless production system for baby leaf red lettuce, since it improves the yield and quality of the product and is able to control the incidence of P. irregulare.

Off-seasonal soilless production of green vegetables in reused substrates in Mediterranean unheated greenhouses

Off-seasonal soilless production of green vegetables in reused substrates in Mediterranean unheated greenhouses

Zero liquid discharge in soilless greenhouse horticulture: solutions to save water and the environment while ensuring an optimal production

Zero liquid discharge (ZLD) should be the future for soilless production. In The Netherlands emission of nutrients and plant protection products to surface water is the main reason to investigate the potentials of cultivation methods without any discharge. In a few other countries water pollution issues is the main motive, but for a majority water shortage and the increasing competition for water of an acceptable quality is reason for the growing need for water efficient cultivation methods. During four years ZLD was investigated for cucumber (2014, 2017) and sweet pepper (2015, 2016). The primary goal was to reuse all drain water, while maintaining a similar yield and quality as in the traditional growing method with regular discharges. To achieve ZLD all practical reasons for growers to discharge the nutrient solution had to be anticipated before. In the ZLD trials technical and strategic solutions were jointly tested and further developed into an adapted growing strategy without any discharge. A number of factors could be mentioned as main reasons for discharge: sodium in the supply water, discharge of filter rinsing water, unbalances in the nutrient solution, no recirculation of the drainwater in the beginning of the cultivation, no disinfection equipment, too low drain storage capacity, appearance of calamities (technical failures) and the amount of remnant nutrient solution left in slabs and tanks at the end of the cultivation. The next step was demonstrating the technical and strategic solutions in a cultivation. In 2014 and 2015 we showed that ZLD-cultivation in stone wool substrate was possible without loss of yield and quality. In 2016 and 2017 the more challenging coir substrate was used to investigate the influence of buffering and sodium accumulation. It appeared that ZLD was possible without loss of production or quality. Appearing problems were more in the field of management of water flows than lack of technical equipment. Special care should come for technical failures of equipment, mostly not enough storage capacity is available.

Variation in health promoting compounds of blueberry fruit associated with different nutrient management practices in a soilless growing system

The objective of this study was to determine and compare the content of total anthocyanins (TACY), total phenolics (TPC) and total antioxidant activity (TAA) of the fruit of ?Bluecrop? highbush blueberry grown under different nutrient management practices in a soilless production system. A field study was carried out in a highbush blueberry plantation situated near Belgrade (Serbia), during the period of 2016-2017. The orchard was planted in the spring of 2016 in 50 l polypropylene pots with 5-year-old nursery plants. Each pot was filled with the mix of pine sawdust (60%), white peat (30%) and perlite (10%), and placed at a distance of 0.8 m within the row and 3.0 m between the rows (4,170 bushes ha?1). The following fertilizer treatments were evaluated: 1. organic fertilizers (Org); 2. mineral fertilizers (Min) and 3. a combination of organic and mineral fertilizers (Org-Min). Soluble NPK fertilizers were applied with irrigation water, whereas granulated mineral and pelleted organic fertilizers were mixed with the substrate. Fruit samples were collected in triplicate at the beginning of ripening, full maturity and the end of the harvest season. No significant effect of harvest time on each of the tested parameters was observed, whereas the content of TACY did not even differ under various fertilizer treatments. TPC in the fruit significantly increased in Org and Org-Min treatments (139.8 and 139.3 mg eq GA 100 g-1 FW, respectively) compared to Min treatment (122.7 mg eq GA 100 g-1 FW), while a considerably high TAA level was found only in berries under Org-Min treatment (0.53 mg asc g-1 FW).

Effects of varying N, P and K concentrations on growth, biomass, yield and nutritional quality of zucchini squash grown under open and polyhousesoilless culture

Soilless production of vegetables is rapidly gaining momentum and popularity especially in the periurban agricultural space. But this requires suitable technological backstopping in terms of substrate, nutrientmanagement and irrigation scheduling. Open and polyhouse experiments were conducted to study the effect ofvarying levels of N, P and K on the growth, biomass, yield and nutritional quality of zucchini hybrid ‘Champion’under soilless culture. The study was carried out with four different NPK levels and seven replications in acompletely randomized design. The results revealed that the nutrient scheduling of 168 ppm N-NO3, 16 ppm Pand 189 ppm K recorded maximum fruit length (24.12cm), fruit girth (44.4mm), fruit weight (335.6g) and yieldper plant (5.71 kg) and per hectare (71.39 tonnes) under open-field soilless culture. However, maximum plantheight (61.25cm), number of leaves (43.33) and total plant dry biomass (146.8g/plant) of zucchini were recordedwith application of 185 ppm N-NO3, 19 ppm P and 224 ppm K. Between open and polyhouse soilless cultivationof zucchini, highest plant height (80.6cm), number of leaves (47.4), number of fruits (22.3) and total plant drybiomass (184.7g/plant) were recorded with polyhouse conditions. Nevertheless, the highest stem diameter(35.2mm), maximum fruit length (23.2cm), maximum fruit girth (42.9mm), fruit weight (315.4g) and yield per plant(5.27kg) and per hectare (65.8t/ha) were recorded with open-field soilless culture. Zucchini plants raised on Arka Fermented Cocopeat registered higher plant height (54.7cm), stem diameter (35.2mm), number of leaves (39.3),total plant dry biomass (139.8g/plant), number of fruits (16.8), fruit length (23.2cm), fruit girth (42.9mm), fruitweight (315.4g) and yield (5.27kg/plant and 65.8t/ha) compared to soil (3.70 kg/plant and 46.3t/ha). The resultsestablished that the growers can increase zucchini yield and fruit quality and advance fruit production (10 days)by changing from soil to soilless culture.

Use of black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae processing residue in peat-based growing media

The Black Soldier Fly (Hermetia illucens (L.), Diptera: Stratiomyidae) is an insect whose larvae thrive on agro-industrial by-products. This study reports the first use of black soldier fly larvae processing residue (BSPR) as an innovative ingredient for growing media. BSPR was characterized and evaluated to partially replace commercial peat (CP) in the production of potted plants. Chemical and microbiological analysis showed the suitability of BSPR for soilless production. Hence, six growing media mixtures (CP 100% + slow acting synthetic solid fertilizer, CP 90% + BSPR 10%, CP 80% + BSPR 20%, CP 70% + BSPR 30%, CP 60% + BSPR 40% and CP 100% without fertilizer) were assessed for the production of baby leaf lettuce, basil and tomato potted plants. Using BSPR in a proportion up to 20%, all investigated crops showed values significantly greater than or comparable to those obtained using CP 100% + slow acting synthetic solid fertilizer. In general, BSPR used in a proportion up to 20% increased the crop growth of baby leaf lettuce, basil and tomato, recording a high total dry weight (+31%, compared to the total average) and the measured leaf parameters (+39% of leaf area, +14% of leaf number), without showing abiotic stresses. This study indicates that BSPR used in a proportion up to 20% might be a valid approach for soilless production of potted baby leaf lettuce, basil and tomato plants.

Managing lettuce seed quality through nitrogen nutrition in soilless production

The commercial value of vegetable seeds has increased during the last decades, which has turned seed production into a specialized horticultural activity. Soilless production has been adopted by some seed producers mainly because of sanitary reasons. An additional advantage of soilless culture would be the possibility of managing plant nutrition with the objective of producing more vigorous seeds. However, there is a lack of knowledge about the effects of specific nutritional changes on seed quality attributes, such as vigor or longevity. In the present study, the effect of N supply during growth of the mother plant on quality parameters in lettuce seeds was evaluated. Two experiments in consecutive seasons were established in a greenhouse located under Mediterranean climate conditions in Santiago, Chile. Plants were subjected to N concentrations ranging from 1 to 30 mM. At harvest, seed production (number of seeds per inflorescence and seed weight), seed germination, vigor and longevity were evaluated. Results indicate that seed production is reduced at N concentrations higher than 10 mM, while seed quality start decreasing at N concentrations higher than 5 mM. No differences were observed in seed productivity between 1 and 5 mM, but seed longevity was improved when produced under 5 mM. Seed light requirement for germination decreases with increasing N supply, however this positive effect coupled with a reduction in germination speed and longevity.

Comparison of substrate hydroponic systems for soilless tomato production

The growth and fruit yield of tomato plants grown under wick type self-suction and drip substrate hydroponic systems was compared. Tomato plants were cultivated under these two substrate hydroponic systems in summer and winter seasons. Four nutrient solutions having different proportions of N and K for vegetative and reproductive stages were applied to plants raised under both the hydroponic systems in both the seasons. Total fruit yield was higher in winter crop raised under wick substrate hydroponic system supplied with nutrient solution containing N: K in the ratio of 1.4: 3 during vegetative stage and 1.7: 3.5 during reproductive stage.

An agroindustrial compost as alternative to peat for production of baby leaf red lettuce in a floating system

Peat alternatives are being developed using materials such as agroindustry compost. The aim of this work was to study whether an agroindustrial compost could be used as substitute for peat in a floating system for cultivating baby leaf red lettuce. For this, two different experiments were carried out over two growing cycles (summer and autumn) in the same greenhouse at the same time. The first experiment compared the two organic substrates (peat and compost) and the second involved a suppressive bioassay using both substrates inoculated with Pythium irregulare. The results showed that compost increased the percentage of seed germination and the quality of baby leaf red lettuce by reducing nitrate accumulation and increasing the antioxidant capacity and vitamin C content of leaves compared with peat. Furthermore, under P. irregulare pressure plants grown in compost showed less incidence of the disease (a higher percentage of plant survival) and produced higher yields. It is concluded that the agroindustrial compost used in this study shows promise as an alternative to peat for use as organic substrate in a sustainable soilless production system for baby leaf red lettuce, since it is not only able to control the effect of P. irregulare, but also improve the yield and quality of the product.

Evaluation of physicochemical properties and enzymatic activity of organic substrates during four crop cycles in soilless containers.

BackgroundOrganic soilless production in containers requires substrates with appropriate physicochemical and biological properties to ensure that production is sustainable and profitable for several production cycles. The main objective of this study was to comprehensively evaluate these properties in three different mixtures of organic substrates (vermicompost [V] and coconut fibers [CF] in ratios 20V80CF, 40V60CF, 60V40CF) for four horticultural crop production cycles (PCs) using vermicompost tea (VT) as the main source of nutrients.ResultsReadily available water (25%) in the control treatment (20V80CF) was below the recommended limit, and dry bulk density (>450 g/L) surpassed the recommended limit in the 60V40CF treatment (p < 0.05). In terms of chemical properties, cations and anions in the saturated media extract decreased significantly to values below established optimal conditions. Furthermore, the substrates presented high enzymatic activity in successive production cycles (p < 0.05), including dehydrogenase (350–400 μg TFF g−1), acid phosphatase (4,700 μg p‐nitrophenol g−1 soil hr−1), and β‐glucosidase (1,200 μg p‐nitrophenol g−1 soil hr−1) activity during transformation from organic matter to inorganic compounds.ConclusionThe 40V60CF treatment presents adequate physicochemical and biological characteristics for reuse for more than four growing cycles when organic supplements are administered.

Nutrient demand modeling of a soilless cucumber crop under greenhouses conditions in a humid tropical climate

ABSTRACT This experiment was conducted in a greenhouse in Vinces Los Rios (Ecuador). The aim of this work is to evaluate the relationship between different parameters and the nutrient demand of a greenhouse soilless cucumber production system in a tropical climate as well as to propose an empirical model for the design of the nutrient supply to the system. Considering the results obtained in this experiment, there was a high correlation between nutrient demands of the system with nutrient supplies and water uptake but not with leaf area index. With respect to the models, nutrient supplies and leaf area index were the most significant variables for nitrate (NO3 −), chloride (Cl−) and manganese (Mn). For calcium (Ca2+), magnesium (Mg2+) and zinc (Zn), nutrients supply was the most significant variable and for the rest of nutrients [phosphates (H2PO4 −), sulfates (SO4 2)−, potassium (K+), sodium (Na+) and iron (Fe)], the three variables assessed were significant.

Influence of Different Soilless Substrates to Morpho-physiological Characteristics and Yield Relations in Strawberries

Some of the advantages of soilless production systems over conventional systems are higher yield, better pest control management and more efficient labor use. Among berries, strawberry responds quite well to soilless production systems. Major yield-affecting factors for strawberries in soilless systems may be listed as; growing medium, source and types of plantlets, density of plants and efficiency of fertigation system. The present research was conducted with strawberry plants (Fragaria x ananassa ‘Camarosa’) grown in four different media; (1) Cocopeat (C), (2) Peat (P) and (3 and 4) 1:1 mixtures with Pumice (Pu), to evaluate the effects of soilless media on marketable yield and root-shoot morpho-physiological parameters. Correlation measurements were made to assess if there is any interaction between yield and any tested morpho-physiological feature. The experiment was conducted in greenhouse, using frigo plantlets (11.6 plantlet/m2) planted in July and through 1 June of following year. Results showed that growth medium had an effect on yield, numbers of developed leaves, shoot-root dry mass, number and length of roots. Yield was correlated with these morphological features. Growth medium also had an influence on plant nutrient accumulations i. e., shoot accumulation of nitrogen (N) and potassium (K) and root accumulation of phosphorus (P) and all the micro-nutrients that with exception of boron (B). There were some interactions between yield and plant nutrient content of tissues determined by correlation analyses. The most striking were negative correlations with yield and shoot N–K amounts and positive correlation with yield and root P amount. Some positive correlations were also found between yield and copper (Cu), manganese (Mn) and zinc (Zn) contents of both shoot and root tissues. Boron (B) contents was correlated only with the root tissues. The medium which had the best overall performance for soilless strawberry production was C + Pu and should be recommended to be used with frigo plantlets of ‘Camarosa’.

Sensor-based irrigation management of soilless basil using a new smart irrigation system: Effects of set-point on plant physiological responses and crop performance

Dielectric moisture sensors are particularly suitable for irrigation management in greenhouse soilless production. Identifying the practical effects of substrate water content set-points on crop performance is crucial for successful sensor-based irrigation. We designed and constructed a prototype cloud-connected system for wireless, sensor-based irrigation management, and tested it on basil, grown in a perlite-coco (1:1 v:v) soilless substrate under greenhouse conditions. Dielectric moisture/salinity sensors (GS3, Decagon Devices, Pullman – WA, USA) were used. The study, with two subsequent experiments, assessed i) the effects of a progressive decline in substrate water availability, corresponding to moisture levels from water holding capacity to ≈0.10 m3 m−3, on the gas exchange parameters and leaf water status of basil plants; ii) the short-term recovery response of plants when re-watered after substrate water content has decreased to different levels; iii) the effects of different irrigation set-points (0.40, 0.30 and 0.20 m3 m−3) and leaching rates (≈8% or ≈18%) on the basil crop performance over a complete growing cycle. No physiological stress responses were observed on basil plants when moisture level was higher than approximately 0.20 m3 m−3, while plants showed drought symptoms at approximately 0.17 m3 m−3, corresponding to a substrate matric potential and hydraulic conductivity of −300 hPa and 0.0005 cm day−1, respectively. Photosynthesis and leaf water potential recovered to values similar to non- stress conditions following a short drought (with moisture level as low as ≈0.10 m3 m−3). Basil growth was similar when plants were grown with irrigation set-points of 0.40, 0.30 or 0.20 m3 m−3 for the complete growing cycle. Fresh weight tended to increase when a higher leaching rate was used, probably because leaching lowered substrate EC. Water use efficiency (basil fresh weight/unit water used) was similar at different irrigation set-points and leaching rates. Our results indicate that the use of a wireless sensor network for real-time sensing of substrate water status, combined with precise information on the effects of water availability levels on plants, is an effective tool for precision irrigation management of greenhouse soilless basil.

Seasonal variations of antioxidants and other agronomic features in soilless production of selected fresh aromatic herbs

Abstract The antioxidant activity, herbal fresh yield, water and nitrogen productivity were studied in selected aromatic herbs of the Lamiaceae family, namely basil (Ocimum basilicum), mint (Mentha viridis), balm (Melissa officinalis) and thyme (Thymus vulgaris), grown in soilless conditions in a typical Mediterranean climate. Seasonal variations of the bioactive substances of the produce were defined. In all crops, total antioxidant activity assessed by (i) ferric reducing antioxidant power/FRAP (μM ascorbic acid equiv/g FW) and (ii) 1,1-diphenyl-2-picrylhydrazyl/DPPH (mg ascorbic acid equiv/g FW), total phenolics (mg gallic acid equiv/g FW) and ascorbic acid content (mg/g FW) were greater in summer (avg. 82.3, 7.01, 8.59 and 0.75, respectively) and lower in winter (avg. 45.4, 2.93, 4.89 and 0.38, respectively), whereas values in spring and autumn were in between (avg. 62.9, 4.8, 7.3 and 0.53, respectively). Natural antioxidants were higher in thyme followed by balm and mint and lower in basil and total antioxidant activity was highly correlated in all cases with phenolics and ascorbic acid. The mean daily evapotranspiration of all crops ranged between 1.8–2.5 mm over the study period. The herbal fresh yield (kg m−2) was greatest in mint (avg. 22.8) followed by basil (avg. 19.3), balm (avg. 15.7) and lowest in thyme (avg. 10.2). Yield per unit of water consumed (kg tn−1) was greatest in mint and basil (avg. 25.5) followed by balm (avg. 21.3) and lowest in thyme (avg. 15.6). Accordingly, yield per unit of nitrogen uptake (kg kg−1 N) was highest in mint and basil (avg. 124.6), followed by balm (avg. 103.9) and lowest in thyme (avg. 76.3). These results may serve as a tool for the better management of greenhouse horticulture schemes under Mediterranean climatic conditions in terms of food-crops rich in antioxidants.

Steam Treated Sawdust as Soilless Growing Media for Germination and Growth of Horticulture Plant

The major substrates used in soilless growing media are peat moss and perlite, where peat moss is a limited and expensive natural resource. Determination of appropriate substrates based on technical and economic feasibility is the vital aspect of research and the key to success in any soilless production system. This research work was performed to evaluate different low-cost and sustainable alternative substrate as soilless growing media for horticulture plant. The objective of this study was to compare the effect of sawdust species and steam treatment, for physico-chemical properties and growth of horticultural plant. This study involves the physical and chemical characterization and growth test of four substrate (pine sawdust, oak sawdust, steamed pine sawdust and steamed oak sawdust) in order to evaluate their use as components of growing media. Steamed oak sawdust (121°C, 30 min) showed adequate physical and chemical properties compared to peat moss for their use as growing media. The growing media were prepared using different mixture proportion to grow Brassica campestris L., Festuca arundinacea and Lespedeza cyrtobotrya Miq. The highest germination, stem length and leaf area of Brassica campestris L., Festuca arundinacea and Lespedeza cyrtobotrya were observed in 30 minute steamed oak sawdust mixture growing media. The steam treatment condition of sawdust used in the growing media significantly positive affected the germination, the stem length and the leaf area.

Covered soilless strawberry production in the field by raised substrate beds

Covered soilless strawberry production in the field by raised substrate beds

Organic Vegetable Crop Production in Controlled Environments Using Soilless Media

Organic vegetables produced in greenhouses and other controlled environments may fill a unique market niche as consumers demand local, high vegetables year round. However, limited technical information supports these production systems and more research is needed to provide recommendations for appropriate substrate mixes and nutrient management. Compost can be used as a substitute for peat-based media, and research results vary widely based on feedstock, compost method, and proportion used in mixes. Most studies consider compost in terms of peat-substitute or replacement and not as a source of fertility in soilless systems. Common challenges in using compost in soilless media are due to immaturity of the compost, poor water holding capacity, and unbalanced salinity and pH. It is possible to certify organic soilless production systems; however, the National Organic Program (NOP) of the U.S. Department of Agriculture has not yet provided clear rules and requirements supporting these systems. The objective of this article is to review the literature on soilless organic vegetable production, summarize results from the more widely studied topic of vegetable transplant production, and point to future research for organic agriculture.

The effect of growing system and growing media on the morphological, biological and sensory quality of sweet pepper (Capsicum annuum L.)

Sweet pepper (Capsicum annuum L.) production is relevant today in Hungary. Due to the importance of the subject, the aim of the study was to evaluate morphological, biological and sensory quality of sweet pepper.The growing experiment was set up at DUNA-R company in Szentes. Three different type of fresh pepper hybrid (Zalkod F1, Gogorez F1, Kapitány F1) were evaluated in unheated plastic house and open field conditions using intensive technology. The fruits were blended and measured with manual digital refractometer (PAL-1, ATAGO). The vitamin C content was determined by the Spanyár-method. Sensory profile analysis was applied with 10 assessors. Based on our results it can be concluded that in forcing the three varieties produced larger fruits in soil culture than in soilless. However in all cases we measured better refraction values in soilless production than in soil culture. Based on the sensory profile analysis the type of growing technology affected mostly morphological parameters.