Browsing by Author "Singh, Sukhbir (TTU)"
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Item A decade of improving nutritional quality of horticultural crops agronomically (2012−2022): A systematic literature review(2024) Kathi, Shivani (TTU); Laza, Haydee (TTU); Singh, Sukhbir (TTU); Thompson, Leslie (TTU); Li, Wei (TTU); Simpson, Catherine (TTU)The ultimate goal of world crop production is to produce more with less to meet the growing population demands. However, concentrating solely on increased quantity of production often impacts the quality of produce. Consumption of crops or foods that do not meet nutritional or dietary needs can lead to malnutrition. Malnutrition and undernutrition are prevalent in a significant portion of the population. Agronomic biofortification of minerals and vitamins in horticultural crops has emerged as a promising approach to address nutrient deficiencies and enhance the nutritional quality of food. Despite numerous research papers on plant nutrient biofortification, there remains a lack of systematic reviews that comprehensively summarize the latest knowledge on this topic. Herein we discuss different agronomic ways to biofortify several horticultural crops over the past decade. This systematic review aims to fill this gap by presenting various methodologies and comparing the outcomes of these methods in respect to nutrient content in plant parts. The review focuses on original research papers collected from various scientific databases including Scopus and Web of Knowledge, covering the most recent literature from the last ten years (2012–2022) for specific studies on the agronomic biofortification macronutrients, micronutrients, and vitamins in horticultural plants with exclusion of certain criteria such as ‘genetic,’ ‘breeding,’ and ‘agronomic crops.’ This review critically analyzes the current state of research and explores prospects for the future in this field. The biofortification of various minerals and vitamins, including calcium, selenium, iodine, B vitamins, vitamin A, and vitamin C, are examined, highlighting the achievements and limitations of existing studies. In conclusion, agronomic biofortification of minerals and vitamins in horticultural crops with further research offers a promising approach to address nutrient deficiencies and improve the nutritional quality of food.Item Biochar Implications Under Limited Irrigation for Sweet Corn Production in a Semi-Arid Environment(2022) Singh, Manpreet (TTU); Singh, Sukhbir (TTU); Parkash, Ved (TTU); Ritchie, Glen (TTU); Wallace, Russell W.; Deb, Sanjit (TTU)The integration of biochar and deficit irrigation is increasingly being evaluated as a water-saving strategy to minimize crop yield losses under reduced irrigation in arid and semi-arid regions such as West Texas. A 2-year (2019 and 2020) open-field study evaluated the effect of two types of biochar amendments (hardwood and softwood) and three irrigation rates [100, 70, and 40% crop evapotranspiration (ETc) replacement] on the physiology, plant growth, and yield of sweet corn in semi-arid West Texas. All experimental units were replicated four times in a split-plot design. The chlorophyll content (ChlSPAD) in 40% ETc dropped significantly compared to 100% ETc and 70% ETc during the reproductive phase. Although water stress under 40% ETc decreased photosynthesis (Pn) to limit transpiration (E) by stomatal closure, it improved intrinsic water use efficiency (iWUE). The above-mentioned gas exchange parameters were comparable between 100% ETc and 70% ETc. Both biochar treatments increased ChlSPAD content over non-amended plots, however, their effect on gas exchange parameters was non-significant. All growth and yield-related parameters were comparable between 100% ETc and 70% ETc, but significantly greater than 40% ETc, except water productivity (WP). Both deficit irrigation treatments improved WP over full irrigation in 2019, but in 2020, the WP gains were observed only under 70% ETc. Hardwood biochar decreased soil bulk density and increased soil porosity, but it had a marginal effect on the water retention characteristics. These results suggest that 70% ETc can be used as an alternative to full irrigation to save water with a minimal yield penalty for sweet corn production in the West Texas region. The hardwood biochar application improved the vegetative biomass significantly but yield marginally during the first 2 years of application. A long-term study is required to test the effect of biochar under deficit irrigation beyond 2 years.Item Biochar Influences Phytochemical Concentrations of Viola cornuta Flowers(2023) Regmi, Abishkar (TTU); Poudyal, Shital; Singh, Sukhbir (TTU); Coldren, Cade (TTU); Moustaid-Moussa, Naima (TTU); Simpson, Catherine (TTU)Edible flowers are a rich source of phytochemicals with potential health benefits. Yet, changes in production practices can influence the phytochemical composition of edible flowers. Practices such as the addition of biochar have been used to affect growing media properties as well as to conserve peat resources. However, there is little known about how biochar affects the phytochemical composition of edible flowers. To determine if biochar affects phytochemicals in Viola cornuta, four cultivars were subjected to different rates of biochar, with and without fertilizer. At the rate of 10% biochar and without fertilizer application, flower polyphenol and flavonoid concentrations were decreased by 10–20% in two cultivars. However, at 25% biochar, flower polyphenol concentrations varied widely. When fertilizer was added, no effects of biochar were seen. Phytochemical characterization of unfertilized plants further revealed that while increased rates of biochar reduced concentrations of certain antioxidant compounds, these compounds were increased when fertilizer was added. Overall, fertilization can counteract some of the negative effects of biochar on Viola cultivars, resulting in higher nutritional quality and an increase in bioactive compounds produced, providing an ability to replace the peat moss with biochar.Item Contribution of Cover Crops and Reduced Tillage Systems for Weed Management in Organic Vegetable Production(2019) Saini, Rupinder (TTU); Singh, Sukhbir (TTU)In recent years, organic vegetable production systems have become an increasingly important segment of agriculture; and weed control is a principal concern for organic vegetable growers. In the absence of herbicides, tillage and cultivation are the most commonly used tools by vegetable growers for managing weeds in organic systems; however, intensive tillage may have adverse effects on soil and environmental health. In recent times, to reduce intensive soil tillage and achieve successful weed management, integration of cover crops with conservation tillage (reduced or no-tillage) is emerging as an innovative alternative production practice in organic farming. Research over the globe has shown that cover crops can be used to control weeds in vegetable fields, and also play an important role in improving productivity of subsequent crops by improving soil physical, chemical, and biological properties. In agronomic crops, the benefits of cover crops in conjugation with reduced tillage on weed management are well documented but, such information is scarcely available for vegetables grown in organic production systems. This review focuses on different types of cover crop species and conservation tillage systems for weed management in organic vegetable production.Item Effect of Colored Shading Nets on the Growth and Water Use Efficiency of Sweet Pepper Grown under Semi-arid Conditions(2021) Mohawesh, Osama (TTU); Albalasmeh, Ammar; Deb, Sanjit (TTU); Singh, Sukhbir (TTU); Simpson, Catherine (TTU); AlKafaween, Nour; Mahadeen, AtifColored shading nets have been increasingly studied in semi-arid crop production systems, primarily because of their ability to reduce solar radiation with the attendant reductions in air, plant, and soil temperatures. However, there is a paucity of research concerning the impact of colored shading nets on various crops grown under semi-arid environments, particularly the sweet pepper (Capsicum annum) production system. This study aimed to investigate the effects of three colored shading net treatments (i.e., white, green, and black shading nets with 50% shading intensity and control with unshaded conditions) on the growth and instantaneous water use efficiency (WUE) of sweet pepper. The results showed that all colored shading nets exhibited significantly lower daytime air temperatures and light intensity (22 to 28 °C and 9992 lx, respectively) compared with the control (32 to 37 °C and 24,973 lx, respectively). There were significant differences in sweet pepper growth performance among treatments, including plant height, shoot dry weight, leaf area, leaf chlorophyll content, and vitamin C in ripened fruit. The enhanced photosynthetic rates were observed in sweet pepper plants under the colored shading nets compared with control plants. WUE increased among the colored shading net treatments in the following order: control ≤ white < black < green. Overall, the application of green and black shading nets to sweet pepper production systems under semi-arid environments significantly enhanced plant growth responses and WUE.Item Effect of deficit irrigation on physiology, plant growth, and fruit yield of cucumber cultivars(2021) Parkash, Ved (TTU); Singh, Sukhbir (TTU); Deb, Sanjit (TTU); Ritchie, Glen (TTU); Wallace, Russell W.Increased water scarcity necessitates the implementation of water-conserving irrigation management practices to sustain crop production,especially in water-limited areas. A two-year field study was conducted during 2019 and 2020 to evaluate the effect of deficit irrigation on physiology, plant growth, and yield of cucumber cultivars. The experiment was conducted in a split-plot design with four irrigation levels (100% ETc (crop evapotranspiration), 80% ETc, 60% ETc, and 40% ETc) as main plot factor and two cultivars (Poinsett 76 and Marketmore 76) as subplot factor with three replications. Results showed that stomatal conductance (gs), transpiration rate (E), photosynthesis rate (Pn), intercellular CO2 concentration (Ci), and leaf area were significantly lower in 60% ETc and 40% ETc compared to 100% ETc while stomatal limitations, intrinsic water use efficiency (WUEi), and relative leaf temperature were significantly higher in 60% ETc and 40% ETc compared to 100% ETc. The observed values of these aforementioned parameters were comparable between 100% ETc and 80% ETc. A decrease in leaf area, as well as a decrease in Pn, resulted in a decline in overall photosynthesis per plant in 60% ETc and 40% ETc compared to 100% ETc. As a consequence of this, plant dry biomass and total fruit yield were significantly lower in 60% ETc and 40% ETc compared to 100% ETc. However, photosynthesis per plant was comparable between 100% ETc and 80% ETc due to comparable Pn and leaf area between them. Because of comparable photosynthesis per plant, plant dry biomass and fruit yield were comparable between 100% ETc and 80% ETc. Marketmore 76 had significantly higher gs, E, Pn, Ci, and leaf area and it had significantly lower stomatal limitations, WUEi, and relative leaf temperature than Poinsett 76. Vegetative dry biomass and total above-ground dry biomass were higher in Marketmore 76 but fruit yield was higher in Poinsett 76. These results suggest that 80% ETc irrigation level and Poinsett 76 cultivar can be recommended for successful cucumber production without causing a significant decline in fruit yield in water-limited Southern High Plains of United States.Item Effect of Deficit Irrigation on Root Growth, Soil Water Depletion, and Water Use Efficiency of Cucumber(2021) Parkash, Ved; Singh, Sukhbir (TTU); Singh, Manpreet (TTU); Deb, Sanjit (TTU); Ritchie, Glen L. (TTU); Wallace, Russell W.Water scarcity is increasing in the world, which is limiting crop production, especially in water-limited areas such as Southern High Plains of the United States. There is a need to adopt the irrigation management practices that can help to conserve water and sustain crop production in such water-limited areas. A 2-year field study was conducted during the summers of 2019 and 2020 to evaluate the effect of deficit irrigation levels and cultivars on root distribution pattern, soil water depletion, and water use efficiency (WUE) of cucumber (Cucumis sativus). The experiment was conducted in a split-plot design with four irrigation levels [100%, 80%, 60%, and 40% crop evapotranspiration (ETc)] as main plot factor and two cultivars (Poinsett 76 and Marketmore 76) as subplot factor with three replications. Results showed that root length density (RLD) was unaffected by the irrigation levels in 2019. In 2020, the RLD was comparable between 100% and 80% ETc, and it was significantly higher in 100% ETc than both 60% Eand 40% ETc. Root surface area density (RSAD) was not significantly different between 100% and 80% ETc, and it was significantly lower in both 60% and 40% ETc than 100% ETc in both years. Soil water depletion was the highest in 40% ETc followed by 60% and 80% ETc, and it was least in 100% ETc in both years. Evapotranspiration (ET) was the highest in 100% ETc followed by 80%, 60%, and 40% ETc. The WUE was not statistically different among the irrigation treatments. However, numerically, WUE was observed in the following order: 80% ETc > 100% ETc > 60% ETc > 40% ETc. The RLD, RSAD, soil water depletion, and ET were not significantly different between ‘Poinsett 76’ and ‘Marketmore 76’. However, fruit yield was significantly higher in ‘Poinsett 76’ than ‘Marketmore 76’, which resulted in higher WUE in Poinsett 76. It can be concluded that 80% ETc and Poinsett 76 cultivar can be adopted for higher crop water productivity and successful cucumber production in SHP.Item Effect of Deficit Irrigation on Root Growth, Soil Water Depletion, and Water Use Efficiency of Cucumber(2021) Parkash, Ved (TTU); Singh, Sukhbir (TTU); Singh, Manpreet (TTU); Deb, Sanjit (TTU); Ritchie, Glen (TTU); Wallace, Russell W.Water scarcity is increasing in the world, which is limiting crop production, especially in water-limited areas such as Southern High Plains of the United States. There is a need to adopt the irrigation management practices that can help to conserve water and sustain crop production in such water-limited areas. A 2-year field study was conducted during the summers of 2019 and 2020 to evaluate the effect of deficit irrigation levels and cultivars on root distribution pattern, soil water depletion, and water use efficiency (WUE) of cucumber (Cucumis sativus). The experiment was conducted in a split-plot design with four irrigation levels [100%, 80%, 60%, and 40% crop evapotranspiration (ETc)] as main plot factor and two cultivars (Poinsett 76 and Marketmore 76) as subplot factor with three replications. Results showed that root length density (RLD) was unaffected by the irrigation levels in 2019. In 2020, the RLD was comparable between 100% and 80% ETc, and it was significantly higher in 100% ETc than both 60% Eand 40% ETc. Root surface area density (RSAD) was not significantly different between 100% and 80% ETc, and it was significantly lower in both 60% and 40% ETc than 100% ETc in both years. Soil water depletion was the highest in 40% ETc followed by 60% and 80% ETc, and it was least in 100% ETc in both years. Evapotranspiration (ET) was the highest in 100% ETc followed by 80%, 60%, and 40% ETc. The WUE was not statistically different among the irrigation treatments. However, numerically, WUE was observed in the following order: 80% ETc > 100% ETc > 60% ETc > 40% ETc. The RLD, RSAD, soil water depletion, and ET were not significantly different between ‘Poinsett 76’ and ‘Marketmore 76’. However, fruit yield was significantly higher in ‘Poinsett 76’ than ‘Marketmore 76’, which resulted in higher WUE in Poinsett 76. It can be concluded that 80% ETc and Poinsett 76 cultivar can be adopted for higher crop water productivity and successful cucumber production in SHP.Item Effects of Non-Leguminous Cover Crops on Yield and Quality of Baby Corn (Zea mays L.) Grown under Subtropical Conditions(2020) Singh, Atinderpal (TTU); Deb, Sanjit (TTU); Singh, Sukhbir (TTU); Sharma, Parmodh; Kang, Jasjit S.Effects of non-leguminous cover crops and their times of chopping on the yield and quality of no-till baby corn (Zea mays L.) were evaluated during two kharif seasons (May-August in 2014 and 2015) under subtropical climatic conditions of Punjab, India. The experiment was laid out in a split-plot design with four replications at Punjab Agricultural University’s Research Farm. Three cover crops (pearl millet (Pennisetum glaucum L.), fodder maize (Zea mays L.), and sorghum (Sorghum bicolor L.)) and the control (no cover crop) were in the main plots and chopping time treatments (25, 35, 45 days after planting (DAP)) in the subplots. During both kharif seasons, the yield (cob and fodder yield) and dry matter accumulation of baby corn following cover crop treatments, especially pearl millet, were significantly (p ≤ 0.05) higher than the control, and improved with increments in chopping time from 25 to 45 DAP. The effect of cover crops on baby corn quality (i.e., protein, starch, total soluble solids, crude fiber, total solid, and sugar content) did not differ among treatments, while increasing increments in chopping time had a significant effect on the protein and sugar content of baby corn. The use of cover crops and increment in chopping time helped in enhancing topsoil quality, especially available nitrogen; yet, the effect of cover crops and their times of chopping on topsoil organic carbon, phosphorus, and potassium did not differ among treatments. During both seasons, there was no significant interaction between cover crop and time of chopping among treatments with respect to baby corn yield and quality, as well as topsoil quality parameters.Item A global meta-analysis of yield and water productivity responses of vegetables to deficit irrigation(2021) Singh, Manpreet (TTU); Singh, Paramveer; Singh, Sukhbir (TTU); Kaur Saini, Rupinder (TTU); Angadi, Sangamesh V.Strategies promoting efficient water use and conserving irrigation water are needed to attain water security to meet growing food demands. This meta-analysis study evaluated the effect of deficit irrigation (DI) strategy on eight vegetables to provide a quantitative estimate of yield and water productivity (WP) responses under variable soil textures, climates, and production systems (open-field and greenhouse). This study analyzed 425 yield and 388 WP comparisons of different DI levels to full irrigation (FI), extracted from 185 published studies representing 30 countries. Moving from the highest (> 80%FI) to the lowest (< 35%FI) irrigation level, the overall yield decline was 6.9 to 51.1% compared to FI, respectively. The WP gains ranged from 8.1 to 30.1%, with 35–50%FI recording the highest benefits. Soil texture affected the yield significantly only under the least irrigation class (< 35%FI), wherein sandy clay and loam recorded the highest (82.1%) and the lowest (26.9%) yield decline, respectively. Among the climates, temperate climate was overall the most advantageous with the least yield penalty (21.9%) and the highest WP gain (21.78%) across various DI levels. The DI application under the greenhouse caused lesser yield reduction compared to the open-field. The WP gains due to DI were also higher for greenhouse (18.4%) than open-field (13.6%). Consideration of yield penalties and the cost of saved irrigation water is crucial while devising the reduced irrigation amounts to the crops. The yield reductions under low to moderate water deficits (> 65%FI) accompanied by gains in WP may be justifiable in the light of anticipated water restriction.Item Greenhouse Cultivation of Cucumber (Cucumis sativus L.) in Standard Soilless Media Amended with Biochar and Compost(2023) Venkataramani, Sujatha (TTU); Kafle, Arjun (TTU); Singh, Manpreet (TTU); Singh, Sukhbir (TTU); Simpson, Catherine (TTU); Siebecker, Matthew G. (TTU)Peat is one of the most commonly used substrates in soilless cultivation. However, peat mining produces a negative carbon footprint, which raises the need for alternative sustainable substrate media. To address this, we studied the impact of peat replacement with a combination of various biochars and cotton burr compost on the growth and yield of cucumber (Cucumis sativus L.), and nutrient concentration of media, plant leaf, and fruit in greenhouse conditions. Two experiments were conducted from Nov 2020 through Jan 2021 (Trial 1) and from Feb to Apr 2021 (Trial 2). The treatments were control (peat, vermiculite, and perlite at 2:1:1) and in the control peat was either fully replaced (hardwood biochar+ compost, softwood biochar+compost, and hemp biochar+compost) or partially replaced up to 50% (v/v) (hardwood biochar+compost, softwood biochar+compost, and hemp biochar+ compost). The control media was more acidic with lowest electrical conductivity than the other treatments. The leaf chlorophyll content and the photosynthetic assimilation rate varied among the treatments in both trials. The final dry shoot biomass was lowest in peatdominated control treatment suggesting biochar-compost in the substrate media contributed in increased dry biomass of the cucumber plant. The total number of fruits per plant and total yield per plant was significantly increased in all the treatments with the highest in hardwood biochar+compost, compared with the control. The nutrient concentration of media, leaf, and fruit indicates that biochar-compost enhances the nutritional status of the media, which supplies essential nutrients to the plant leaf and fruit while growing in different substrate compositions. Our results suggest that the replacement of peat with full or partial proportions of biochar-compost can produce similar and, in some cases, even better growth, yield, and physiology in potted cucumber than in the unamended control treatment.Item Increasing vitamin C through agronomic biofortifcation of arugula microgreens(2022) Kathi, Shivani (TTU); Laza, Haydee (TTU); Singh, Sukhbir (TTU); Thompson, Leslie (TTU); Li, Wei (TTU); Simpson, Catherine (TTU)Vitamin C (Vit C) is an essential micronutrient and antioxidant for human health. Unfortunately, Vit C cannot be produced in humans and is ingested through diet while severe deficiencies can lead to scurvy. However, consumption is often inconsistent, and foods vary in Vit C concentrations. Biofortification, the practice of increasing micronutrient or mineral concentrations, can improve the nutritional quality of crops and allow for more consistent dietary levels of these nutrients. Of the three leading biofortification practices (i.e., conventional, transgenic, and agronomical), the least explored approach to increase Vit C in microgreens is agronomically, especially through the supplemental application of ascorbic acid. In this study, biofortification of Vit C in microgreens through supplemental ascorbic acid was attempted and proven achievable. Arugula (Eruca sativa 'Astro') microgreens were irrigated with four concentrations of ascorbic acid and a control. Total Vit C (T-AsA) and ascorbic acid increased in microgreens as supplementary concentrations increased. In conclusion, biofortification of Vit C in microgreens through supplemental ascorbic acid is achievable, and consumption of these bio-fortified microgreens could help fulfill the daily Vit C requirements for humans, thereby reducing the need for supplemental vitamins.Item Influence of Arbuscular Mycorrhizal Fungi on Physiology and Yield of Eggplant in Organic Soilless Production System(2022) Shaik, Azeezahmed (TTU); Singh, Sukhbir (TTU)Recent studies suggest that arbuscular mycorrhizal fungi (AMF) have the potential to improve the growth and yield of eggplant (Solanum melongena L.) under soil-based organic production systems. However, the application of AMF in organic soilless vegetable production in a greenhouse has not been well studied, creating an important knowledge gap. Therefore, two greenhouse experiments [Experiment 1 (E1) and Experiment 2 (E2)] were conducted to investigate the effect of AMF (Glomus spp.) on the growth, gaseous exchange, and yield of eggplant fertilized with various liquid organic fertilizers (OFs) and inorganic fertilizers (IFs) in a soilless greenhouse production system. The experiment was conducted in a split-plot design with four replications in which liquid OFs [OF1 (5N–1P–1K), OF2 (0N–5P–5K and 3N–3P–3K), OF3 (3N–1P–1K), OF4 (5N–1P–2K), OF5 (3.7N–2.7P–3.7K), and OF6 (3N–3P–5K)], and IFs [IF1 (6N–4P–4K) and IF2 (4N–0P–1K and 1N–3P–5K)] were randomized as main plot factor, and AMF [inoculated and uninoculated (control)] as a subplot factor. Results indicate that AMF inoculation had no significant effect on the growth, gaseous exchange, and yield parameters of eggplant. Among different OFs, the eggplant fertilized with OF6 resulted in a 4.3% and 3% reduction of leaf area compared with top-performing IF1 treatment in E1 and E2, respectively. Further, the OF6 treatment resulted in a 12% and 15% reduction in total yield per plant compared with IF1 in E1 and E2, respectively. The differences in plant gaseous exchange parameters were also nonsignificant for eggplants fertilized with different OF and IF treatments in both E1 and E2. These results conclude that Glomus spp. were not associated with a significant increase in the yield of eggplant in the soilless production system. However, OFs were performing similar to IFs in terms of growth and yield, which could be due to a higher nutrient availability of these OFs, which are highly useful for the production of eggplant in greenhouse soilless production systems.Item The Negative Effects of High Rates of Biochar on Violas Can Be Counteracted with Fertilizer(2022) Regmi, Abishkar (TTU); Singh, Sukhbir (TTU); Moustaid-Moussa, Naima (TTU); Coldren, Cade (TTU); Simpson, Catherine (TTU)Increasing costs and environmental issues regarding excessive use of peat moss is impacting the horticultural industry. Biochar is a valuable substrate additive that has the potential to reduce the use of peatmoss in greenhouse production. However, its varying effects on ornamentals requires that individual species and cultivars of crops must be evaluated to determine the threshold for benefits. Viola cornuta is a high value ornamental crop; however, information on how different rates of biochar rates affect productivity and physiology of Viola cultivars in container production is not known. To determine if biochar rates could increase the productivity of Viola, we mixed a peat-based substrate with 10, 25, and 50% (w:w) hardwood biochar in two studies on four cultivars. Without fertilizers, 10 and 25% biochar improved plant biomass, growth, root length, and flowering, but 50% biochar was found to have negative effects on plant growth and flowering. Cultivars varied in their response to biochar rates. When fertilizer was applied in the second experiment, biochar rates did not impact growth parameters or flowering. These results suggest that up to 25% biochar can be used in Viola production without detrimental impacts. However, 50% biochar can be used with the addition of fertilizer without negatively affecting plant growth. Biochar can have a short-term impact on the growth characteristics of Viola plants in container production, but fertilization and growing period of Viola may influence these effects. These results indicate that biochar could be the suitable replacement for peat moss, with up to 50% biochar rate in Viola production reducing the environmental and economic burden for peat moss.Item Potential of Biochar Application to Mitigate Salinity Stress in Eggplant(2020) Parkash, Ved (TTU); Singh, Sukhbir (TTU)Salinity stress is among the major abiotic stresses prevailing in arid and semiarid areas such as the southern high plains of the United States. In these areas, both declining quality of groundwater and cultivation practices have resulted in increased accumulation of salts in the root zone. The occurrence of excessive salts in the root zone is detrimental for plant growth and economic yield. Recently, biochar has received a great consideration as a soil amendment to mitigate the detrimental impacts of salinity stress. However, the effectiveness of biochar to mitigate the salinity stress depends on the feedstock type, pyrolysis temperature and time, soil type and properties, and plant species. Therefore, a pot experiment in a greenhouse was conducted to 1) examine the effects of salinity stress on physiology, shoot and root growth, and yield of eggplant (Solanum melongena L.), and 2) evaluate the potential of hardwood biochar and softwood biochar to mitigate the damaging effects of salinity stress on eggplant. The experiment was conducted in a split-plot design with three salinity levels of irrigation water [S0 (control, 0.04 dS·m−1), S1 (2 dS·m−1), and S2 (4 dS·m−1)] as main-plot factor and three biochar treatments [B0 (control, non-biochar), Bh (hardwood biochar), and Bs (softwood biochar)] as subplot factor with four replications. Results showed that stomatal conductance (gS) and photosynthesis rate decreased significantly, while leaf temperature and electrolyte leakage increased significantly with increase in irrigation water salinity levels. Root growth (root length density and root surface area density), shoot growth (plant height, stem diameter, and leaf area), and yield of eggplant declined with increase in levels of salinity stress. Biochar application helped to enhance gS and photosynthesis rate, and to decrease leaf temperature and electrolyte leakage in leaf tissues of plants. This resulted in better root growth, shoot growth, and fruit yield of eggplant in treatments amended with biochar than non-biochar (control) treatment. There was no significant difference in the effect of two types of biochars (hardwood and softwood biochar) on physiology, root growth, shoot growth, and yield of eggplant. Therefore, it can be concluded that softwood and hardwood biochars could be used to minimize the detrimental impacts of salinity stress in eggplant.Item A Review on Potential Plant-Based Water Stress Indicators for Vegetable Crops(2020) Parkash, Ved (TTU); Singh, Sukhbir (TTU)Area under vegetable cultivation is expanding in arid and semi-arid regions of the world to meet the nutritional requirements of an ever-growing population. However, water scarcity in these areas is limiting vegetable productivity. New water-conserving irrigation management practices are being implemented in these areas. Under these irrigation management practices, crops are frequently exposed to some extent of water stress. Vegetables are highly sensitive to water stress. For the successful implementation of new irrigation practices in vegetable crops, it is of immense importance to determine the threshold water deficit level which will not have a detrimental effect on plant growth and yield. Along with this, plant response and adaptation mechanisms to new irrigation practices need to be understood for the successful implementation of new irrigation practices. To understand this, water stress indicators that are highly responsive to water stress; and that can help in early detection of water stress need to be identified for vegetable crops. Plant-based water stress indicators are quite effective in determining the water stress level in plants because they take into account the cumulative effect of water stress due to declining soil moisture status and increased evaporative demand of the atmosphere while determining the water stress level in plant. Water stress quantification using plant-based approaches involves direct measurements of several aspects of plant water status and indirect measurements of plant processes which are highly sensitive to water deficit. In this article, a number of plant-based water stress indicators were critically reviewed for (1) their efficacy to determine the level of water stress, (2) their potential to predict the yield of a crop as affected by different water-deficit levels and (3) their suitability for irrigation scheduling in vegetable crops.Item Root distribution, soil water depletion, and water productivity of sweet corn under deficit irrigation and biochar application(2023) Singh, Manpreet (TTU); Singh, Sukhbir (TTU); Deb, Sanjit (TTU); Ritchie, Glen (TTU)Root modifications can play a vital role in crop adjustments to soil water deficit. It is important to understand root growth and soil water depletion patterns to develop effective cropping systems, especially in semi-arid regions like Texas High Plains (THP). This study evaluated root growth, soil water depletion, and water productivity (WP) of sweet corn under three deficit irrigation treatments [100 %, 70 % and 40 % crop evapotranspiration (ETc)] and biochar application (hardwood and softwood). The experimental units were replicated 4 times in a split-plot design. The results revealed no interaction between irrigation and biochar treatments for almost all measured parameters. The 70 % ETc treatment increased the root length density (RLD) over 100 % ETc during 2019, while no differences were observed among irrigation treatments in 2020. Both deficit irrigations (70 % and 40 % ETc) increased soil water depletion compared to 100 % ETc, the highest being in 40 % ETc. The 70 % ETc maintained a similar yield and increased WP by 21 % compared to 100 % ETc across two years. However, 40 % ETc resulted in significant decline in yield and WP in 2020. The hardwood biochar increased RLD over no biochar treatment without affecting the soil water status and WP. Long-term studies are needed to investigate biochar effects beyond two years of application. In case of limited water availability, 70 % ETc can be recommended as an alternative to 100 % ETc in the THP of the US.Item Simultaneous biofortification of vitamin C and mineral nutrients in arugula microgreens(2024) Kathi, Shivani (TTU); Laza, Haydee (TTU); Singh, Sukhbir (TTU); Thompson, Leslie (TTU); Li, Wei (TTU); Simpson, Catherine (TTU)Microgreens have shown promise in improving the overall nutritional value of diets due to their high nutrient density. Agronomic biofortification, is an efficient strategy for enhancing the nutritional value of crops, including microgreens. This study aimed to biofortify vitamin C and other essential nutrients in arugula microgreens using four treatments containing 0.25 % ascorbic acid, pH adjusted with different bases: KOH, Ca(OH)2, ZnCO3, or NaOH and a deionized water control. The results indicate that ascorbic acid-treated microgreens had more vitamin C, greater fresh weight and % dry matter than the control. The ascorbic acid + Zn treatment had an 135 % average increase in vitamin C compared to the control. Microgreens treated with ascorbic acid also showed increased levels of minerals that are present in the nutrient solution, such as potassium, sodium, calcium, and zinc. This research contributes to the growing interest in microgreens biofortification and their role in addressing multi-nutrient deficiencies.Item Use of natural products for weed management in high-value crops: An Overview(2019) Saini, Rupinder (TTU); Singh, Sukhbir (TTU)In recent years, organic vegetable production systems have become an increasingly important segment of agriculture; and weed control is a principal concern for organic vegetable growers. In the absence of herbicides, tillage and cultivation are the most commonly used tools by vegetable growers for managing weeds in organic systems; however, intensive tillage may have adverse effects on soil and environmental health. In recent times, to reduce intensive soil tillage and achieve successful weed management, integration of cover crops with conservation tillage (reduced or no-tillage) is emerging as an innovative alternative production practice in organic farming. Research over the globe has shown that cover crops can be used to control weeds in vegetable fields, and also play an important role in improving productivity of subsequent crops by improving soil physical, chemical, and biological properties. In agronomic crops, the benefits of cover crops in conjugation with reduced tillage on weed management are well documented but, such information is scarcely available for vegetables grown in organic production systems. This review focuses on different types of cover crop species and conservation tillage systems for weed management in organic vegetable production.Item Vitamin C biofortification of broccoli microgreens and resulting effects on nutrient composition(2023) Kathi, Shivani (TTU); Laza, Haydee (TTU); Singh, Sukhbir (TTU); Thompson, Leslie (TTU); Li, Wei (TTU); Simpson, Catherine (TTU)The consumption of plants plays an important role in human health. In addition to providing macro and micronutrients, plants are the sole sources of several phytonutrients that play a major role in disease prevention. However, in modern diets, increased consumption of cheaper, processed foods with poor nutritional value over fruits and vegetables leads to insufficient consumption of essential nutrients such as vitamin C. Taking supplements can address some of the insufficient nutrients in a diet. However, supplements are not as diverse or bioavailable as the nutrients in plants. Improving the abundance of nutrients in plants will reduce the amounts that need to be consumed, thereby reducing the price barrier and use of supplements. In this study, broccoli (Brassica oleracea var. italica) microgreens grown in a controlled environment were biofortified for increased vitamin C content. The microgreens grown on growing pads were treated with supplemental nutrient solutions. Treatments were applied four to five days after germination and included four different concentrations of ascorbic acid specifically, 0% (control), 0.05%, 0.1%, 0.25% and 0.5%, added to the nutrient solution. Microgreens with turgid cotyledons and appearance of tip of first true leaves were harvested about 14 days after germination and were analyzed for biomass, chlorophylls, carotenoids, vitamin C and other minerals content. The ascorbic acid improved the microgreens’ fresh biomass, percent dry matter, chlorophylls, carotenoids, vitamin C, and potassium content. Moreover, this study also mapped out the correlation between ascorbic acid, phytochemicals, and broccoli microgreens’ mineral composition. The total vitamin C was positively correlated to K and negatively correlated to chlorophylls, N, P, Mg, Ca, S, and B (p < 0.01). These relationships can be applied in future vitamin C biofortification research across different microgreens. In conclusion, vitamin C was increased up to 222% by supplemental ascorbic acid without being detrimental to plant health and mineral composition.