Lettuce Yield Research Articles

Biochar, compost and/or NPK fertilizer affect the uptake of potentially toxic elements and promote the yield of lettuce grown in an abandoned gold mine tailing

Background and study objectives: The low soil quality status and the high concentrations of potentially toxic elements (PTEs) found in gold mine tailings make them unfit for crop production. Assessing the possibility of mine tailings for crop production after mining is important since the presence of these PTEs harms food safety and human health. In this study, we aimed to investigate the effects of biochar, poultry litter compost, and inorganic fertilizer on the uptake of PTEs and the soil quality improvement of tailings from a decommissioned mine tailing in Ghana.Materials and methods: Rice husk biochar, poultry litter compost, and NPK were applied alone or in combination to the abandoned mine tailings at the rate of 5 t ha−1. After a 42-day pot experiment, we extracted the content of nutrients and PTEs in the soil and plant, and determined their uptake by the Lactuca sativa L.Results and discussion: Rice husk biochar, poultry litter compost and NPK applied alone or in combination significantly increased the soil pH, organic matter, available P as well as the CEC (Ca2+, K+, Mg2+, Na+) but reduced the exchangeable acidity in the mine tailings. Additionally, tailings amended with NPK increased the N uptake by 42%. Also, tailings amended with 2.5 t ha−1 biochar + 2.5 t ha−1 NPK increased both P and K uptake by 128% and 101%, respectively. For PTE uptake (i.e., Pb, Hg, As, Cd, and Cr), biochar, poultry litter compost and their combinations reduced the Hg uptake (mg kg−1) in the pot by a maximum 49% as compared to the control. Plausible formation of metal-hydroxo complexes at high pH with its consequent strong adsorption of Hg and presence of exchangeable K which contributed to the ion binding strength of the amended mine tailings reduced mobility and uptake of Hg by the lettuce. However, biochar, compost, and/or inorganic fertilizer enhanced Cd, Cr, and Pb uptake, which may pose lettuce food chain contamination problems for the inhabitants.Conclusion: As a result, we conclude that the use of inorganic NPK fertilizer and rice husk biochar can be used to improve the soil quality of abandoned gold mine tailings for safe food production, minimize Hg uptake by lettuce, and lower the associated environmental risk.

THE GROWTH AND YIELDS OF LETTUCE (LACTUCA SATIVA L.) ON A AQUAPONIC NFT (NUTRIENT FILM TECHNIQUE) SYSTEM WITH THREE DIFFERENT TYPES OF FISH

Introduction. Lettuce Cultivation (Lactuca sativa L.) with an aquaponic system can be used as an alternative to meet the food needs of the community in the midst of reduced agricultural land. The purpose of this research is to determine the types of fish that affect the growth and yield of lettuce (Lactuca sativa L.). The types of fish used in this research were tilapia, catfish and goldfish measuring 6-8 cm with a stocking density of 20 individuals. The observation variables included number of leaves, chlorophyll and wet weight of lettuce (Lactuca sativa L.). Methods. The research data were analyzed using One Way Anova Test and Duncan Multiple Range Test (DMRT). Result and Analysis. The results showed that goldfish gave optimal results on the number of leaves and wet weight of lettuce (Lactuca sativa L.), while catfish gave optimal results on the lettuce (Lactuca sativa L.) chlorophyll. Discussion. The different types of fish have a significant effect on the number of leaves, chlorophyll content and wet weight of lettuce plants (Lactuca sativa L.). the goldfish treatment (P3) gives optimal result on the number of leaves and wet weight of lettuce plants, while catfish treatment (P2) gives optimal results on chlorophyll of lettuce plants in the NFT aquaponic system.

Effect of Surface and Subsurface Drip Irrigation and Furrows Irrigation System on Water Productivity, Growth and Yield of Lettuce (Lactuca Sativa L)

A field experiment was conducted in Al-Yusufiya district - Al-Mahmoudiya district, Baghdad province during the winter season 2021, to study improving the efficiency and management of water use and the productivity of lettuce under different irrigation systems. The Nested-Factorial Experiments design was used, where the main plots include the first factor, irrigation levels (I1) 50%, (I2) 75%, (I3) 100, (I4) 125%, (I5) 150% ETpan. After depleting 35% of the available water and in terms of climatic data from the American Evaporative Basin, Class A. Then the main factor is divided into three replicates, and the coefficients of the second factor are distributed randomly within each replicate, which includes the irrigation system: surface drip irrigation, a plant line drip line (S1) and a two plant line drip line (S2), The subsurface drip irrigation system is a plant-line drip line (SS1) and a two plant drip line (SS2) and furrows irrigation system (SI.) The results show that the highest field water use efficiency is 108.2 and 104.1 kg m-3 for the subsurface drip irrigation system (SS2) and (SS1) and at irrigation level I2. While the field water use efficiency of the surface drip irrigation system was 72.07 kg m-3 at the level of irrigation I3 for treatment (S1) and for treatment (S2) it reached 68.90 kg m-3 at the level of irrigation I4. As for irrigation in-furrow (SI), it reached 33.30 kg m-1 for irrigation level I2 and the highest yield was 286.2 Mg. ha-1 for I5SS2 treatment, and the lowest yield was 62.50 Mg. ha-1 for I1S1 treatment. The highest average head length and head circumference were 46.19 and 69.20 cm at I5SS1 treatment, respectively.

Aplikasi Kompos Azolla (Azolla sp.) dan Pupuk Hayati Pada Budidaya Selada (Lactuca sativa L.) Organik

Organic fertilizer plays an essential chemical role such as in providing macro and micro nutrients. One of many plants which is able to be used as organic fertilizer which contains high level of nitrogen for the soil is Azolla pinnata. Biofertilizer is defined as a fertilizer which contains beneficial bacteria which may improve plant’s yield. The aims of this research is to study the application of composted Azolla and M-Bio Biofertilizer on lettuce (Lactuca sativa L.) cultivation. This research was conducted at the research field of Faculty of Agriculture, Siliwangi University by an altitude of 356 m above sea level on August to October 2022. This research was arranged based on Completely Randomized Design in factorial patterns, consisted of two factors. The first factor was the dosage of composted Azolla fertilizer, consisted of three dosages, i.e 10 ton/ha, 15 ton/ha, 20 ton/ha. The second factor was the consentration of M-Bio biofertilizer, consisted of the levels, i.e 10 ml/L, 15 ml/L, 20 ml/L. Each treatment was replicated 3 times, therefore, there were 27 experimental plots. Data were analysed by using the analysis of variance with F test and continued by Duncan’s Multiple Range Test with 5% of critical value. The result of this research shows that there is no interraction between composted Azolla fertilizer and M-Bio consentration on growth and yield of lettuce (Lactuca sativa L.).

Pengaruh Efek Sisaan Eco Enzyme dan Pupuk Kandang Ayam terhadap Pertumbuhan dan Produksi Selada

A study consisted of two growing seasons of lettuce was held to observe the residual effect of eco enzyme and chicken manure on the growth and yield of lettuce on the second growing season. The research was held in Medan and was done using factorial randomized block design, with two treatments and three replications. The first factor was the concentration of eco enzyme, with three levels of 0, 1 and 2 ml/L. The second one was the dose of chicken manure, with three levels of 0, 15 and 30 tons/hectare. The application of the eco enzyme and chicken manure was done only on the first growing season. The parameters were: number of leaves, root volume, fresh weight and the total yield of lettuce. The result showed that there was a residual effect of eco enzyme and chicken manure application on the growth and production of lettuce. The concentration of eco enzyme had a very significant effect on the number of leaves at 14 DAP, but there was no significant effect on other parameters. The relationship between eco enzyme concentration and the number of leaves at 14 DAP was linear. The dose of chicken manure had a very significant effect on all variables at each time of observation. The relationship between the dose of chicken manure and the number of leaves at 14, 21 and 35 DAP, the fresh and total yield was also linear. The relationship between the dose of chicken manure and the number of leaves at 28 DAP and the root volume was quadratic, with the optimum doses of chicken manure were: 27.05 and 22.5 tons/ha, respectively. No interaction was observed between the concentration of eco enzyme and the dose of chicken manure on all variables at each time of observation.

Quantification of total polyphenols, antioxidants, anthocyanins and secondary metabolites by UPLC VION IMS QTOF MS/MS analysis in green and red lettuce cultivars

Lettuce is an important leafy vegetable and an excellent source of phytochemicals in human diets. However, the metabolic levels in different green and red type lettuce varieties are not fully explored. Therefore, it is important to explore and identify the selected health promoting secondary metabolites in green and red type lettuce varieties with having different phenotypic characteristics. In this study, we explored the selected secondary metabolites, total polyphenol, antioxidants activities, total flavonoids and anthocyanin contents in 32 lettuce varieties of green and red color. The results showed that green and red type lettuce varieties showed a significant difference in lactupicrin, chlorogenic acid, caffeoylmalic acid, syringic acid and quercetin 3-D-galactoside. Selected metabolites showed a significant variation in green and red type lettuce varieties depends upon different color and phenotypic characteristics. Total flavonoids and anthocyanin contents were found more in red type lettuce varieties while the total polyphenols and total antioxidants were found significantly higher in green type lettuce varieties. Tentative identified 78 metabolites with online databases, the published literature and standards including phenolic acid, flavonoids and glycosylated flavonoids. The metabolomic profiling was present at significantly difference in green and red type lettuce varieties which suggested the significant variation between green and red type lettuce varieties to secondary metabolism. This study provides a selection of lettuce varieties for further studies on the basis of color and phenotypic characteristics for improving the nutritional value, quality and yield of lettuce.

Zinc (Zn) mitigates copper (Cu) toxicity and retrieves yield and quality of lettuce irrigated with Cu and Zn-contaminated simulated wastewater.

Owing to a competitive interaction, zinc (Zn) contained in highly Cu-contained wastewater was hypothesized to mitigate Cu toxicity-induced negative effects on the growth and quality of lettuce. Thus, growth, metal accumulation and biochemical responses of lettuce irrigated with simulated wastewater (SW, control), Cu-contaminated SW (CuSW, 20mg Cu L-1), Zn-contaminated SW (ZnSW, 100mg Zn L-1) and both Cu- and Zn-contaminated SW (CuZnSW, 20mg Cu and 100mg Zn L-1) were evaluated. Results revealed that irrigation with CuSW negatively affected growth (dry matters, root length and plant height) and quality (low mineral concentrations) of lettuce, which were associated with higher Cu uptake. Irrigation with Zn + Cu-contaminated SW retrieved Cu toxicity and improved root and shoot dry matters and root length by 13.5%, 46% and 19%, respectively compared to that with alone Cu-contaminated SW. Moreover, CuZnSW improved lettuce leaf quality compared to CuSW and increased concentrations of Mg (30%), P (15%), Ca (41%), Mn (24%) and Fe (23%). Moreover, compared to CuSW, CuZnSW improved flavonoids (54%), total polyphenolic compounds (1.8-fold), polyphenolic acids (77%) and antiradical activities (16.6%). Most importantly, Zn addition boosted up lettuce Cu tolerance index by 18% under Cu-contaminated SW treatment. Pearson's correlation analysis among various growth and mineral parameters demonstrated that shoot Zn concentration was positively related to elemental concentrations, phytochemical contents and antioxidant activity under Cu-contaminated environment. Thus, it is concluded that Zn supplementation retrieves negative effects of Cu toxicity to lettuce grown with Cu-contaminated wastewater.

Effect of Depletion Levels of Available Water and Phosphate Fertilization on Water Consumption and Yield of Lettuce

Effect of Depletion Levels of Available Water and Phosphate Fertilization on Water Consumption and Yield of Lettuce

Microalgae from Nordic collections demonstrate biostimulant effect by enhancing plant growth and photosynthetic performance.

We investigated the biostimulant potential of six microalgal species from Nordic collections extracted with two different procedures: thermal hydrolysis with a weak solution of sulfuric acid accompanied by ultrasonication and bead-milling with aqueous extraction followed by centrifugation. To this aim, we designed a phenotyping pipeline consisting of a root growth assay in the model plant Arabidopsis thaliana, complemented with greenhouse experiments to evaluate lettuce yield (Lactuca sativa L. cv. Finstar) and photosynthetic performance. The best-performing hydrolyzed extracts stimulated Arabidopsis root elongation by 8 - 13% and lettuce yield by 12 - 15 %. The in situ measured photosynthetic performance of lettuce was upregulated in the efficient extracts: PSII quantum yield increased by 26 - 34%, and thylakoid proton flux increase was in the range of 34 - 60%. In contrast, aqueous extracts acquired by bead-milling showed high dependence on biomass concentration in the extract and an overall plant growth enhancement was not attained in any of the applied dosages. Our results indicate that hydrolysis of the biomass can be a decisive factor for rendering effective plant biostimulants from microalgae. This article is protected by copyright. All rights reserved.

Scalable coupled aquaponics design: Lettuce and tilapia production using a parallel unit process approach

Coupled aquaponics is the integration of recirculating aquaculture systems (RAS) with hydroponic cropping systems (HCS) into a single system with shared water treatment units. Potential benefits of integration include water conservation, reduced reliance on finite mineral fertilizers, and intensive year-round location-independent production of lean proteins and fresh vegetables. However, coupled aquaponic practitioners have found minimal commercial success to date. This has been mostly due to the use of system designs which are not based on contemporary water treatment principles, especially those for commercial aquaculture. Instead, conventional coupled aquaponic system design has been based on a linear framework assuming fish wastes are readily utilized as plant fertilizers, with minimal emphasis on waste treatment or individual component hydraulic retention times. The result has been economic failures due to misbalancing the cost of inputs, the value of the outputs, and the time required to reach a marketable harvest size for both crops: fish and plants. This manuscript provides theoretical calculations based on existing standards in commercial RAS and HCS for sizing plant, fish, and biofiltration units focused on nitrogenous waste production from fish. Successful integration of HCS and RAS is defined as achieving industry standard production timelines for lettuce (seed to harvest time of 35 days) and Nile tilapia (fry to a 624 g average harvest weight in 35 weeks). Equations and examples to calculate lettuce yield, daily lettuce nitrogen requirement, fish feed rates to achieve specific nitrogen production rates, and fish tank and biofilter volumes are provided.

Emergent molecular traits of lettuce and tomato grown under wavelength-selective solar cells.

The integration of semi-transparent organic solar cells (ST-OSCs) in greenhouses offers new agrivoltaic opportunities to meet the growing demands for sustainable food production. The tailored absorption/transmission spectra of ST-OSCs impacts the power generated as well as crop growth, development and responses to the biotic and abiotic environments. To characterize crop responses to ST-OSCs, we grew lettuce and tomato, traditional greenhouse crops, under three ST-OSC filters that create different light spectra. Lettuce yield and early tomato development are not negatively affected by the modified light environment. Our genomic analysis reveals that lettuce production exhibits beneficial traits involving nutrient content and nitrogen utilization while select ST-OSCs impact regulation of flowering initiation in tomato. These results suggest that ST-OSCs integrated into greenhouses are not only a promising technology for energy-neutral, sustainable and climate-change protected crop production, but can deliver benefits beyond energy considerations.

Effectiveness of Gamba Organic Fertilizer on Increasing Growth and Production of Organic Lettuce (Latuca sativa L) as well as its Effect on Production Costs

This study aimed to determine the response of growth and production of lettuce plants to the application of organic Gamba fertilizer and to see the effect on lettuce production costs. This research aims to provide information to the general public, especially farmers, regarding efforts to apply the efficient use of organic fertilizers to the growth and yield of lettuce. This research was carried out by comparing the cultivation of lettuce that was given Gamba organic fertilizer with that which was not given organic fertilizer. The research variables were plant height, leaf quality, number of leaves, and stem weight. The results of the study would be statistically analyzed using the t-test to determine whether the independent variables partially had a significant effect or not on the dependent variable with a significant degree used was 5 %. The results showed that the application of Gamba organic fertilizer significantly differed in plant growth, height, leaf quality, number of leaves and lettuce production. The production of lettuce cultivation with Gamba organic fertilizer treatment reached 13.2 tons/ha; without treatment, it was 10.2 tons/ha. Regarding financial aspects, the income obtained from cultivation using Gamba organic fertilizer was higher than cultivation without treatment, IDR 596,000 and Rp. 469,000, with an R/C ratio of 1.3 and 1.0, this business using Gamba organic fertilizer is feasible to expand.

Non-Thermal Plasma and Soilless Nutrient Solution Application: Effects on Nutrient Film Technique Lettuce Cultivation

Soilless cultivation is one of the best examples of the sustainable intensification concept due to the high use efficiency of its inputs. Managing the nutrient solution through a closed cycle system represents a crucial objective to be pursued, but the recovery of the nutrient solution requires chemical correction and sanitization. The application of non-thermal plasma (NTP) in agriculture promotes the safety of the nutrient solution, decreasing the use of chemicals. The aim of this study was to evaluate the effects of cold plasma on the nutrient depletion, yield, and qualitative traits of lettuce. A closed soilless system (nutrient film technique) was used to compare different NTP treatments: control, low ionization (LI), and high ionization (HI) in two successive lettuce cycles. No significant differences within the nutrient depletion trends were observed. The treated lettuce’s yield was 12% higher than that of the control, characterized by a higher total soluble solid content and a significantly higher electrical conductivity and titratable acidity than the control. The ion content was higher in HI plants, as were the contents of nitrogen, phosphorous, and potassium. In HI plants, the leaf pigments were higher, but no significant changes were observed for the antioxidant content. Cold plasma is a promising strategy that brings benefits to the crop.

Effects of Goat Manure, Biochar, and NPK Applications on Growth and Nutrient Concentrations of Lettuce

During the last decades, biochar (BC) gained increasing importance amongst scholars. Though, only a few studies explored the effects of the combined application of BC with manure on plant growth and nutrient concentrations. This study investigates the effects of separate and joint applications of goat manure (GM) and its derived BC on the growth and mineral element concentrations in lettuce. A completely random design was used in the field experiment. Two factors consisted of GM, BC at 5 Mg ha-1 and 10 Mg ha-1 combined with inorganic fertilizers [nitrogen, phosphorus, and potassium (NPK)] at 100%, 50%, and 0% were applied to the soil before planting the lettuce and, ANOVA analysis and Duncan test (at α=5%) were conducted. The results showed that a joint application of inorganic and organic fertilizers affects significantly the yield and yield parameters of the lettuce whilst the separate application of organic fertilizer affects significantly the lettuce content in N, P, K, Ca and Mg. Compared to GM, the application of GM-derived BC increases significantly the lettuce content in Zn and decreases its content in Cu. In addition, the highest total yield of lettuce was obtained with a joint combination of GM, BC, and 100% NPK (100 kg N ha-1, 100 kg P2O5 ha-1 and 100 kg K2O ha-1). Consequently, this combination of organic and inorganic fertilizers is favorable fertilization in producing lettuce.

Far-red radiation during indoor cultivation reduces lettuce nutraceutical quality and shortens the shelf-life when stored at supra optimal temperatures

To improve yield in lettuce during indoor cultivation, far-red radiation (FR, 700–800 nm) is often added to the photosynthetic active radiation (PAR, 400–700 nm). Different scenarios was applied in this study: in one scenario FR is applied throughout the 16 h photoperiod (FR-Day); in another scenario FR is applied for a short duration (1 h) at the end of the day (FR-EOD). We have shown that FR-Day is optimal for improving yield, whereas FR-EOD is optimal for production efficiency (Zou et al., 2019). Here, we evaluated the impact of both scenarios on the postharvest quality of lettuce. Shelf-life of excised packaged (polyethylene film) leaves was monitored during dark storage at 4 and 16 ℃, respectively. FR during cultivation decreased the content of major health-promoting metabolites at harvest, especially under FR-Day. At 4 ℃, shelf-life was not affected by the cultivation regime. At 16 ℃, instead, FR was associated with increased postharvest deterioration rate and reduced overall visual quality throughout storage. The reduced shelf-life following FR during cultivation was related to elevated O2•− content along with decreased activity of enzymatic (superoxide dismutase) and reduced levels of non-enzymatic (carotenoids, total phenolics, and flavonoids) antioxidants. We conclude that FR during cultivation especially under FR-Day is associated with reduced nutraceutical quality at harvest, and potentially shorter shelf-life. Notably, the latter was only observed under inappropriate postharvest temperature management.

The Effect of LED Light Spectra on the Growth, Yield and Nutritional Value of Red and Green Lettuce (Lactuca sativa).

Controlled Environment Agriculture (CEA) is a method of increasing crop productivity per unit area of cultivated land by extending crop production into the vertical dimension and enabling year-round production. Light emitting diodes (LED) are frequently used as the source of light energy in CEA systems and light is commonly the limiting factor for production under CEA conditions. In the current study, the impact of different spectra was compared with the use of white LED light. The various spectra were white; white supplemented with ultraviolet b for a week before harvest; three combinations of red/blue lights (red 660 nm with blue 450 nm at 1:1 ratio; red 660 nm with blue 435 nm 1:1 ratio; red 660 nm with blue at mix of 450 nm and 435 nm 1:1 ratio); and red/blue supplemented with green and far red (B/R/G/FR, ratio: 1:1:0.07:0.64). The growth, yield, physiological and chemical profiles of two varieties of lettuce, Carmoli (red) and Locarno (green), responded differently to the various light treatments. However, white (control) appeared to perform the best overall. The B/R/G/FR promoted the growth and yield parameters in both varieties of lettuce but also increased the level of stem elongation (bolting), which impacted the quality of grown plants. There was no clear relationship between the various physiological parameters measured and final marketable yield in either variety. Various chemical traits, including vitamin C content, total phenol content, soluble sugar and total soluble solid contents responded differently to the light treatments, where each targeted chemical was promoted by a specific light spectrum. This highlights the importance of designing the light spectra in accordance with the intended outcomes. The current study has value in the field of commercial vertical farming of lettuce under CEA conditions.

Biochar for Wastewater Treatment and Soil Improvement in Irrigated Urban Agriculture: Single and Combined Effects on Crop Yields and Soil Fertility

This work evaluated the agronomic and soil fertility effects of using municipal wastewater or anaerobically treated wastewater for irrigation and applying biochar to a soil from the Guinea savanna agroecological zone of Ghana. For this purpose, untreated municipal wastewater (WW), the effluent of an anaerobic wastewater filtration system (TWW), and clean water (CW) were used as irrigation water in a pot trial. Additionally, rice-husk biochar in the form of raw biochar (RB), water-washed biochar (WB), and biochar used as wastewater filter material (FB) were added to the soil, testing the influence on soil fertility and crop yield. Lettuce and carrot were selected for the pot study, grown on soil mixed with the biochar types at 20 t ha−1 and irrigated with either WW, TWW, or CW. Our results indicated higher crop growth morphology and yields (up to 90% increase) by WW and TWW than CW. The average yield of carrot (34.1 g pot−1) and lettuce (29.3 g pot−1) with TWW irrigation were the highest, followed by 31.2 and 27 g pot−1 with WW, then the lowest yields of 21.7 and 19.5 g pot−1 of carrot and lettuce irrigated with CW respectively. Compared to WW, TWW was more beneficial to plant development, causing an up to 10% increase in crop yields. Soils with FB and WB produced similar agronomic effects and plant nutrient concentrations but were lower than pots amended with RB. Nevertheless, combining RB with TWW showed increasing effects on pH, CEC, and P availability in the highly weathered acidic soil. The results suggest a beneficial effect of biochar-filtered wastewater on soil fertility and crop growth, offering the potential to enhance resource use efficiency in irrigated urban agroecosystems.

Urine and grey water based liquid fertilizer – Production and the response of plants

Plant cultivation is a key aspect of future long-distance space missions, and the creation of an efficient food system will not be possible without it. The production of fertilizer in space is based on the recovery of water and nutrients from wastewater, such as urine and grey water. In this study, the fertilizer production process was conducted in an aerobic, activated sludge reactor, where nitrification and the process of carbon removal take place. Treated streams have three potential factors that could affect the plants growth in a hydroponic system (anionic surfactants, nutrients deficiencies, high salinity). The effect of these factors was examined for two hydroponic configurations. Their influence on lettuce yield, quality parameters and stress response were investigated and compared to the control cultivation. The results showed that the main cause of a decrease (up to 24%) in the yield productivity of plants grown on nitrified urine and grey water is oxidative stress originated from a deficiency of elements, not from used anionic surfactant. Enrichment with nutrients resulted in the restoration of proper protein synthesis and an increase in the activity of antioxidant enzymes, which was positively reflected in the qualitative and quantitative parameters of the enriched cultivation (fresh leaves mass equal to 103% of the control). Results also show that Sodium Methyl Cocoyl Taurate (SMCT) surfactant itself after biological treatment used in plant cultivation has no negative effects reflected in lettuce yield or quality.

Effects of biochar on the phytotoxicity of polyvinyl chloride microplastics

Polyvinyl chloride microplastics (PVC-MPs) are toxic to crops, resulting in economic losses during agricultural production. Owing to its strong adsorption capacity, biochar can effectively remove MPs from water. It is presumed that biochar can alleviate the phytotoxicity of PVC-MPs. To verify this hypothesis, the effects of different concentrations of corncob biochar (CCBC) on the phytotoxicity of PVC-MPs were investigated using hydroponic experiments. The results showed that PVC-MPs attached to lettuce roots substantially inhibited the growth and quality of lettuce. The tested CCBC adsorbed the PVC-MPs. At appropriate concentrations, CCBC alleviated the inhibitory effect of PVC-MPs on lettuce yield; however, it decreased some quality indicators. The single PVC-MPs induced oxidative damage to lettuce, as demonstrated by the increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) content. Addition of CCBC considerably decreased the contents of H2O2 and MDA in the lettuce shoots but increased the H2O2 content in the roots. These findings indicate that CCBC may alleviate the adverse effects caused by PVC-MPs to the lettuce shoots but aggravate the toxic effects on the lettuce roots. This study provides a basis for understanding the removal of the phytotoxicity of MPs.

Enhancing yield of lettuce through irrigation and nitrogen management in a subtropical Inceptisol

Abstract To address the dearth of management of lettuce in the Indo-Gangetic plains, field experiment was conducted on a sandy loam Inceptisol for optimizing the irrigation, nitrogen requirement and economics of lettuce for three years. Four irrigation levels (conventional, I1 and irrigation at 0.6, 0.8, 1.0 irrigation water to cumulative pan evaporation (IW/CPE) ratio, as I2, I3 and I4) and three nitrogen management (100% recommended dose of N i.e., RDN as inorganic, N1; 50:50% RDN as inorganic: vermicompost, N2 and 100% RDN as vermicompost, N3) was laid out in thrice replicated split plot design. All the major physiological characteristics like plant height, number of leaves, average head diameter was improved with I4, N2 and their interaction (I4N2). Maximum average head yield (10.6 t ha−1) was obtained with I4 and I3, 10.5 t ha−1 for N2, while I4N2 yielded 11.3 t ha−1. Maximum water productivity (11.8 kg m−3) was obtained under I2N2. A strong non-linear relationship was detected between yield with irrigation water applied (). Higher soil moisture extraction (80.2%) in top 0–30 cm and lower (19.8%) for 30–45 cm depth and maximum leaf dry matter yield, nutrient concentrations and uptake was found with I4N2 and I3N2. The moderate deficit irrigation and optimum nutrient at I3N2 was found best for optimizing yield, higher water productivity, nitrogen economy and monetary returns of lettuce.