Browsing by Author "Parkash, Ved (TTU)"
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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 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 (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 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.