Levels Of Supply Research Articles

Distribution of Trophic Resources in a Rodent Community in the High-Mountain Zone of the Republic of Dagestan

Quantitative and qualitative characteristics of nutrition of some cohabiting rodent species in the High-Mountain Zone of the Republic of Dagestan have been studied. The diet of S. uralensis consisted of 23, C. gud, of 22, M. arvalis, of 27, C. migtatorius, of 26, and D. nitedula, of 19 plant species. The most diverse diet was found in the common vole and gray hamster. In spring, sedges dominated in the diets of rodents, in the summer, rations consisted mainly of cereals, and autumn, predominantly from the species of the forbs and legume groups. In all, except for the forest dormouse, the conjugation of diets with the structure of herbaceous vegetation was revealed. The maximum values of the degree of similarity of the diets of rodents were found in pairs of wood mouse – Gudaur vole, Gudaur vole – gray hamster, and common vole – gray hamster. As a result, a sufficient level of food supply, a wide range of microstations, and intrapopulation adaptation mechanisms make it possible for the considered rodent species to live together in the study area.

Boosting Geranyl Diphosphate Synthesis for Linalool Production in Engineered Yarrowia lipolytica.

Linalool is a pleasant-smelling monoterpenoid widely found in the essential oils of most flowers. Due to its biologically active properties, linalool has considerable commercial potential, especially in the food and perfume industries. In this study, the oleaginous yeast Yarrowia lipolytica was successfully engineered to produce linalool de novo. The (S)-linalool synthase (LIS) gene from Actinidia argute was overexpressed to convert geranyl diphosphate (GPP) into linalool. Flux was diverted from farnesyl diphosphate (FPP) synthesis to GPP by introducing a mutated copy of the native ERG20F88W-N119W gene, and CrGPPS gene from Catharanthus roseus on its own and as part of a fusion with LIS. Disruption of native diacylglycerol kinase enzyme, DGK1, by oligo-mediated CRISPR-Cas9 inactivation further increased linalool production. The resulting strain accumulated 109.6mg/L of linalool during cultivation in shake flasks with sucrose as a carbon source. CrGPPS expression in Yarrowia lipolytica increased linalool accumulation more efficiently than the ERG20F88W-N119W expression, suggesting that the increase in linalool production was predominantly influenced by the level of GPP precursor supply.

Improvement and validation of a decision support system to maintain optimal nutrient levels in crops grown in closed-loop soilless systems

To support growers in their transition towards recycling of water and fertilisers in soilless crops, an algorithm consisting of mass balance models was developed and applied via the decision support system NUTRISENSE. This algorithm is commissioned to readjust the composition of the nutrient solution (NS) supplied to plants after a chemical analysis of the drainage solution (DS), aiming to match nutrient input with crop nutrient uptake, thus maintaining the nutrient concentrations within target ranges in the root zone. The algorithm was tested in a pilot study conducted in a commercial greenhouse with tomato grown in a closed-loop soilless system and the data were further used for scenario analyses to assess its sensitivity to inaccuracies in the parameters fed to the models. The nutrient concentrations in the root solution were closer to the target levels after supplying NS readjusted using the current algorithm, thus confirming its efficiency to maintain optimal nutrient levels in the root zone of soilless crops when the DS is recycled. The scenario analysis showed that the algorithm is not sensitive to inaccuracies in input parameters related to the daily volume of NS supplied to the crop, or to the volume of available NS per plant in the soilless system. However, it was moderately sensitive to inaccurate determinations of the nutrient concentrations in the DS. Furthermore, a case study with a closed-loop soilless crop of cucumber managed with NUTRISENSE was conducted, aimed to confirm the efficiency of the algorithm to maintain optimal nutrient levels in the root environment. The case study showed that the readjustment of the nutrient supply using NUTRISENSE could successfully maintain the EC, pH and macronutrient levels within a range of ± 10% variation from the target level. Only SO42- showed a larger discrepancy than ± 10% from the target value, because the supply level of this macronutrient was not estimated directly through the current algorithm but indirectly, through the anion to cation balance. However, this problem can be easily tackled by setting a minimum level of SO42- supply as a present value in NUTRISENSE.

Effects of soil potassium levels on dry matter and nutrient accumulation and distribution in cotton

BackgroundPotassium (K) is an essential nutrient for plant growth and development. However, plant fertilization ignoring the soil K level is very likely to cause excessive fertilizer use, and further arouse a series of side effects. This study investigated the response of cotton growth to different soil K levels and the uptake of major nutrients, aiming to evaluate the appropriate K supply level for cotton growth. Using a random block design with 6 soil K levels, we conducted 18 micro-zones field experiments over two continuous years. The soil available K concentration of each treatment was K1 (99.77–100.90 mg·kg−1), K2 (110.90–111.26 mg·kg−1), K3 (123.48–128.88 mg·kg−1), K4 (140.13–145.10 mg·kg−1), K5 (154.43–155.38 mg·kg−1), and K6 (165.77–168.75 mg·kg−1). Cotton nutrient contents, soil nutrient contents, accumulation and distribution of dry matter in cotton were determined, and the relationships between K content in soil and plants and dry matter accumulation were analyzed.ResultsThe soil K content had a significantly positive relationship with dry matter and K accumulation in cotton plants. There were significant differences in dry matter accumulation, single-plant seed cotton yield, mineral nutrient uptake and the proportion of K accumulation in reproductive organs among different soil K levels. The results showed that there was significant difference between K4 and lower K level treatments (K1 and K2), but no significant difference between K4 and higher K level treatments (K5 and K6) in dry matter, single-plant seed cotton yield, or accumulation, distribution and seed cotton production efficiency of N, P and K.ConclusionThe soil K level of K4 was able to provide sufficient K for cotton growth in our experiment. Therefore, when the soil K level reached 140.13 mg·kg−1, further increasing the soil K concentration no longer had a significant positive effect on cotton growth.

Optimum integration of latent heat storage in a solar thermal system for industrial processes: In series or in parallel?

Solar thermal energy holds great potential in decarbonizing the process industry to achieve net-zero emissions. This study focuses on analyzing the optimum integration of latent storage in solar heating and cooling for an industrial process, by comparing two configurations. Configuration 1 connects the thermal energy storage (TES) in parallel with the solar collector and the process, allowing the solar collector outlet stream to be directed to either the TES or the process. Configuration 2 connects the TES in series with the solar collector and the process, ensuring that the solar collector outlet stream always passes through the TES before reaching the process. The solar system also includes a rotary Fresnel collector that supplies heating and cooling to a dairy factory. The two configurations are evaluated by dynamic simulations including transients such as clouds and start-ups. The findings reveal that the parallel layout needs more components to achieve the same controllability and energy supply level as the series layout. Consequently, the parallel layout incurs a higher cost and complex operation. Considering the objective of finding a cost-effective and straightforward solution for the industry sector, the study concludes that connecting the TES in series represents the optimal configuration.

Simulating Operating Performance of Alternative Configurations of LNG Bunkering Stations

Recently, due to the great need to promote environmentally sustainable maritime transport, alternative energy sources to traditional fossil fuels have been proposed to reduce ship emissions. Among few alternative scenarios, most experts recognize Liquefied Natural Gas (LNG) as the most promising solution in the short to medium term. However, there are still some critical issues related to the future expansion of bunkering stations and the LNG-fuelled fleet. Firstly, there is the need for a sufficiently extensive international network of bunkering facilities. Secondly, the layout and location of bunkering stations impact the efficiency of ship bunkering operations, cost reduction and the safety of the surrounding areas. Last, the in-progress Russian-Ukrainian conflict is causing serious unbalances in gas supply and prices, especially for Europe. Specifically, in the case of Italy, gas imports represent the seventh most imported commodity. Due to the changed geopolitical scenarios, interest has arisen in investigating the technical and operational characteristics of LNG bunkering stations and comparing different configurations with a view to increasing Italy’s independence from other foreign countries, focusing on degasifies that could promote new infrastructures that make available LNG in ports. In this paper we highlight the importance of reducing ship emissions and investigate some technical and operational characteristics of LNG bunkering stations. We present a simulation study to analyse quantitatively the operating performance of different LNG bunkering technologies in a port terminal and their impact on the efficiency and overall cost within the whole goods’ supply chain. In particular, we evaluate and compare bunkering time, throughput and refuelling costs in alternative layouts, referring to marine terminals located near urban areas. The aim of this research is to verify whether ports with infrastructure embedded in metropolitan areas could provide, safely, a valuable contribution to the green transition by efficiently handling an adequate level of LNG supply, especially referring to the present Italian interest in increasing independence from foreign countries. For this purpose, we present four dynamic discrete event simulations of all the main LNG bunkering configurations and present their dynamic performance sampled over two consecutive years after a warmup period of 6 months. The simulation conceptual models have been created by the authors based on analyses of those configurations and then processed and implemented within the simulation software Witness Horizon 23®, used for experimentation. This is the first time that a simulation study is presented for comparing different configuration of LNG bunkering stations. The results presented here confirm that simulation is a key science to address these complex problems and it represents a major added value for the development of new infrastructures embedded in supply chains and able to favour green transition. Concerning the present study, the simulation output reveals that, although the increase in the price of LNG over the past year has had a strong negative impact on the propensity to activate LNG refuelling stations at maritime terminals, Truck-To-Ship, or Ship-to-Ship with small feeder ships, and Port-To-Ship configurations appear to be flexible and particularly suitable for port terminals located near urban areas. However, the final the choice of the most suitable LNG bunkering station requires further and specific inside investigation as well as considerations on the Decision Maker Strategies and Attitudes.

Comparative study of phytoremediation of chromium contaminated soil by Amaranthus viridis in the presence of different chelating agents

Chromium is a harmful heavy metal to the environment due to the toxicity induced by it to plants and other living organisms. High concentration of Cr in soil poses severe toxicological problems ecosystem. Phytoremediation using different plants is an economical and environment-friendly method for removing Cr from soil. The addition of chelating agents augments the phytoextraction using plants.The present study aimed to augment the Cr phytoremediation capacity of Amaranthus virdis, a predominant plant species in the Cr-contaminated open dumpsites of Bangalore. . Phytoextraction of Cr by Amaranthus viridis was studied in the presence of different chelating agents viz. ethylenediaminetetraacetic acid (EDTA), citric acid (CA), growth promoting hormone- indoleacetic acid (IAA) and NPK fertiliser. A. viridis grown under different concentrations (5, 10 and 20 mg/Kg) of Cr were treated with 0.5g EDTA/Kg of soil, 0.5g CA/Kg of soil, 1mg IAA/Kg of soil and NPK (125 mg of nitrogen, 45 mg of phosphorous and 156 mg of potassium per Kg of soil). Results indicated that CA, at 10 mg/kg Cr supply, induced the highest uptake (up to 29.25 µg/plant). Furthermore, the study revealed that CA amendment induced maximum Cr uptake in A. viridis at all levels of Cr supply as compared to other amendments. This was due to the increased solubility of Cr in the presence of citric acid and the amelioration of oxidative stress due to Cr to plants by citric acid. This study inferred that the non-hyperaccumulating plant, A. virdis could be used as a phytoremediator for Cr in the presence of citric acid in the places where it is grown abundantly.

An integrated ride-matching and vehicle-rebalancing model for shared mobility on-demand services

Shared mobility on demand (MoD) services are receiving increased attention as many high-volume ride-hailing companies are offering shared services (e.g. UberPool, LyftLine) at an increasing rate. Also, the advent of autonomous vehicles (AVs) promises further operational opportunities to benefit from these developments as AVs enable a centrally operated and fully connected fleet. There are two fundamental tasks for a shared MoD service: ride-matching and vehicle-rebalancing. Traditionally, these two tasks are optimized sequentially and independently. The paper formulates an integrated ride-matching and vehicle-rebalancing problem for shared MoD services which simultaneously optimizes these two tasks. We propose a graph-based methodology to solve the integrated ride-matching and vehicle-rebalancing problem with a novel rebalancing cost term quantifying supply contributions of vehicle scheduling to zonal supply deficit balances (deviations from the desired supply level) in the network. The integrated model performance is validated using a large-scale empirical shared MoD dataset by comparing with state-of-the-art sequential models. Generally, the integrated model improves the level of service and sustainability performance compared to the sequential model. The detailed analysis shows that the vehicle rebalancing in the integrated model is replaced by a more effective ride-matching and penalizing singly served trips in the integrated model can further improve its sustainability performance.

FACTORS AFFECTING FOOD SECURITY OF THE REGION

The purpose of the study is to specify the external driving forces that have a possible impact on the formation of a system of regional food security. The article presents the results of a study of the features of various factors that have both a positive and a negative impact on the state of the object of study in the context of political, social, economic and technological approaches to the classification of these factors. The main emphasis in the work is on the problems and prospects for the development of the agro-industrial complex, on the final success of which the level of food supply of the regions of Russia directly depends.
 The relevance of the study is determined by the fact that under the influence of the global pandemic crisis and the economic sanctions imposed by European countries, a number of different environmental factors have formed that determine the main trends in the development of the food security system for the Russian regions. In the current economic conditions, the main task of national importance is to maintain and improve the standard of living of the country's population.

Regarding the generation of time resolved industrial waste heat profiles

The timely transient energy supply or insufficient temperature levels of industrial waste heat (IWH) hinders the full exploitation of its energy and CO2 emission reduction potentials. This outlines the necessity for investigating IWH in a time resolved manner, which, however, is still widely disregarded, especially in generalized industrial energy system analyses and research. Within this study, we present our developed first-of-its-kind approach, which addresses this topic from a holistic system perspective and enables the generation of time resolved IWH profiles for all industrial subsectors. The backbone of our approach is the distinction of energy-intensive subsectors (e.g. Non-Metallic Minerals) and non-energy-intensive subsectors (e.g. Food & Beverage Production), as both vary in regard to their underlying process designs, production routines and data accessibility. Concerning the first group we found that time resolved IWH profiles can be generated by combining process specific data in a bottom-up manner with temperature gradients of the whole production route throughout the paradigm of discrete event simulation. We investigated further that IWH profiles of non-energy-intensive subsectors are depicted by examining existing subsector resolved waste heat fractions and combining this information with plant-specific load profiles in a top-down manner. We practically prove our findings for both groups within (1) a case study of generating IWH profiles of a real-life cement production mill as part of energy-intensive subsectors and (2) outline the analysis of waste heat fractions for the non-energy-intensive subsector of food production exemplarily. Both cases reflect the above findings successfully and with satisfactory results, which can therefore be regarded as basis for future research work concerning time resolved IWH.

Influence of Nutritional Stress on Female Allocation and Somatic Growth in the Simultaneously Hermaphroditic Polychaete Worm Ophryotrocha diadema.

Hermaphrodites are characterized by plastic sex allocation, by which they adjust their allocation of reproductive resources according to mating opportunities. However, since the plasticity of sex allocation is influenced by environmental conditions, it may also be affected by species-specific life-history traits. In this study, we explored the trade-off between nutritional stress due to food deficiency and the investment of resources in female allocation and somatic growth in the simultaneously hermaphroditic polychaete worm, Ophryotrocha diadema. To achieve this, we exposed adult individuals to three food supply levels: (1) ad libitum-100% food supply, (2) intense food deficiency-25% food resources, and (3) extreme food deficiency-0% food resources. Our findings show a progressive decrease in female allocation in the numbers of cocoons and eggs and in body growth rate of O. diadema individuals as the level of nutritional stress increased.

Tomato puree quality from field to can: Effects of water and nitrogen-saving strategies

Processing tomato is a main source of phytomicronutrients in the human diet due to its micronutrient content, and the diversity of derived products consumed worldwide. A large proportion of processing tomatoes are grown under Mediterranean climate where increasing water scarcity and heat are expected to reduce yields and to have negative impacts on fruit quality. Despite this, the effects of changes in fresh fruit quality on processing and end-product quality have been under-investigated. It therefore seems imperative to work along the food chain to improve food sustainability while maintaining quality and access to important phytonutrients. The present study adopts a holistic approach from field to processing plant, assessing the effects of reduced water and nitrogen supplies on yields, fresh fruit quality and suitability for processing, and puree quality. The 5-year trial included eight varieties, several levels of water and nitrogen supply, and two processes. It was found that water deficit induced a decrease in fresh commercial yield, partially compensated by an increase in dry matter content. The yield loss was the result of a lower number of fruits per plant, while the average fruit weight and biochemical composition showed little change. Water use efficiency decreased above 120% of water demand restoration and improved under low nitrogen supply. Puree viscosity and dry matter content increased with water deficit with beneficial effects for the industry, while the reduction of nitrogen supply did not affect puree quality. This work highlighted the possibility of monitoring quality traits in tomato puree directly from field. Nevertheless, the trade-offs between WUE, quality and yield need to be optimized. Selection of varieties rich in lycopene could be a promising avenue as they appear more tolerant to water deficit. This work also stressed the need to reassess the crop coefficient for new varieties, to improve evaluation of water needs.

Changes in Antioxidant Metabolism and Plant Growth of Wild Rocket Diplotaxis tenuifolia (L.) DC cv Dallas Leaves as Affected by Different Nutrient Supply Levels and Growing Systems

It has been widely assessed that the quality and quantity of nutrient supply and the growing system can strongly affect the growth and development of plants, the nutritional quality, and the levels of minerals, phytochemicals, and vitamins. The study was conducted on leaves of wild rockets grown in soil and soilless to examine the effect of growing conditions and mineral fertilization doses on the quality, mineral content, enzymatic and non-enzymatic antioxidants, and oxidative stress. The experiment was conducted in a plastic greenhouse into two independent sectors, one for soil-bound cultivation and another equipped for soilless cultivation. The crop was subjected to a high compared to a low-input fertilization program. Ion exchange chromatography, spectrophotometrically, and microbiological techniques were utilized. The soil-bound treatments increased the fresh weight, leaves number, chloride content, and microbial load. Exogenous application of higher nitrogen levels significantly boosted the ascorbate and hydrogen peroxide levels. Wild rocket growth in soilless showed a higher content of sulphates and polyphenols, and enhanced activity of the antioxidant enzymes dehydroascorbate reductase and monodehydroascorbate reductase. The fertilization rate and the cultivation system did not modify the content of nitrates, except in the soilless system treated with high fertilization program, where nitrate levels slightly exceeded regulatory limits. The yield and overall quality of wild rockets can be improved by combining the proper fertilizer dose with the growth system (soilless or soil) and suggested fertilization management is provided.

Developing Effective Strategies for Obesity Prevention.

Nutrition policies can work with clinical treatments to address the obesity epidemic. The United States has passed beverage taxes at the local level and calorie labeling mandates at the federal level to encourage healthier consumption. Nutritional changes to federal nutrition programs have been either implemented or suggested; evidence shows that the changes that have been implemented have resulted in improvements in diet quality and are cost-effective in decreasing the increase in obesity prevalence. A comprehensive policy agenda that addresses risk of obesity on multiple levels of the food supply will have meaningful long-term effects on obesity prevalence.

A Hybrid Signal Processing Technique for Identification and Categorization of Faults in IEEE-9 Bus System

A hybrid signal processing technique (HSPT) is proposed in this manuscript for identification and categorization of faults in electrical transmission network. A fault indicator (FI) is suggested by decomposition of the currents by application of Alienation coefficient (ACF), Stockwell transform (ST) and Hilbert transform (HT) for identification of faults. An indicator for ground involvement during faulty condition (SGFI) is being suggested to detect the type of fault. The categorization of faults is done by utilizing faulty phase numbers and SGFI. It is found that the proposed technique is effective in identification of faults and to classify them in different scenarios together with fault on A-phase to ground (AGF), double phase fault (ABF), fault on two phases and ground (ABGF), three phase fault (ABCF) and three phase fault including ground (ABCGF). Study is done and validated on IEEE-9 bus system using MATLAB/Simulink environment. The effectiveness and applicability of the proposed technique with respect to different parameters of faults such as Fault Incidence Angle, Fault Impedance, Line loading, Generator Supply and Noise level is also checked. The results shows that proposed scheme is able to detect and classify the faults in different faulty events.

Pre-Feasibility Assessment Tool for Solar Industrial Process Heating

The industrial sector demands 25% of global energy as heat, where one-third is used at temperatures below 150 °C. Nevertheless, the installed solar heating capacity in the industry is only 0.02%, even though the integration of solar heating systems into production processes could significantly reduce fossil fuel consumption at a competitive cost. Among other reasons, this low penetration is due to the final users’ lack of knowledge of solar heating technologies. As a result, a free pre-feasibility assessment tool was developed for non-specialised users to evaluate the possibility of integrating solar heat into their processes using basic information. This tool uses transient simulation to estimate a feasible solar heating system through the parametric optimisation of the solar collection area, thermal storage volume, heat exchange capacity, and solar integration schemes at the supply level and costs. A commercial facility in Mexico was analysed using the developed tool as a case study. However, even when this is not a design tool, the calculated solar collector area, storage tank volume, and investment were only 2.1%, 9.0%, and 2.3% higher than reported by the solar designer. Pre-feasibility assessment tools are essential to overcome the certainty gap between end users and solar designers, thus enhancing the possibility of implementing solar heating systems in various commercial and industrial processes.

Subaqueous Topographic Deformation in Abandoned Delta Lobes—A Case Study in the Yellow River Delta, China

Reduction in river discharge and sediment load has left deltaic lobes in the world’s many river deltas starving, but knowledge of how the subaqueous topography of these abandoned subdeltas responds to environmental changes is limited. In this study, we aimed to determine the long-term dynamics of the subaqueous seabed of abandoned delta lobes to advance current knowledge. As a case study, we selected an abandoned subdelta on the Yellow River Delta of the Bohai Sea, China, for which three-decade long (1984–2017) bathymetric data and long-term river discharge and sediment load records are available. We analyzed the seafloor surface change and quantified the void space from the sea water surface to the seafloor. In addition, we surveyed the seafloor surface with an M80 unmanned surface vehicle carrying a multibeam echo sounder system (MBES) in 2019 to obtain high-resolution microtopography information. We found that a net volume of 5.3 × 108 m3 of sediment was eroded from the study seabed within an area of 3.6 × 108 m2 during 1984–2017. This volumetric quantity is equivalent to 6.89 billion metric tons of sediment, assuming a bulk density of 1.3 t/m3 for the seabed sediment. The seabed erosion from 0 to −5 m, from −5 to −10 m, and below −10 m has showed a similar increasing trend over the past 33 years. These findings suggest that seabed erosion in this abandoned subdelta will very likely continue, and that other abandoned delta lobes in the world may have been experiencing similar seabed erosion due to the interruption of the sediment supply and sea level rise. It is not clear if the seabed erosion of abandoned delta lobes would have any effect on the stability of the coastal shoreline and continental shelf.

Application Top Five Exponential Logistic Technologies During the Covid-19 Pandemic

Abstract In a pandemic situation such as Covid-19, it is essential to keep contact to a minimum, but it is also important to maintain an acceptable supply level to the population. This paper presents a general analysis of selected exponential logistics technologies, particularly the possibilities of their use in the implementation of logistics chains, or the segment related to storage and distribution during a pandemic. Exponential technologies are those whose performance doubles yearly, but whose cost is halved. Five logistics technologies have been selected that meet the exponentiality criteria and can address pandemic-related issues under certain conditions. Each of these technologies can be used in specific segments of logistics systems. The technologies meet the exponentiation criterion and contribute to increased performance, efficiency, and process automation These technologies are becoming part of a new approach to logistics and are directly related to the advent of Industry 4.0. This paper analysis and subsequent application concern logistics technologies such as internet of things, automated guided vehicles, drones, digital twins, and artificial intelligence.

Innovative Solutions for Drought: Evaluating Hydrogel Application on Onion Cultivation (Allium cepa) in Morocco

Throughout the last decade, and particularly in 2022, water scarcity has become a critical concern in Morocco and other Mediterranean countries. The lack of rainfall during spring was worsened by a succession of heat waves during the summer. To address this drought, innovative solutions, including the use of new technologies such as hydrogels, will be essential to transform agriculture. This paper presents the findings of a study that evaluated the impact of hydrogel application on onion (Allium cepa) cultivation in Meknes, Morocco. The treatments investigated in this study comprised two different types of hydrogel-based soil additives (Arbovit® polyacrylate and Huminsorb® polyacrylate), applied at two rates (30 and 20 kg/ha), and irrigated at two levels of water supply (100% and 50% of daily crop evapotranspiration; ETc). Two control treatments were included, without hydrogel application and with both water amounts. The experiment was conducted in an open field using a completely randomized design. The results indicated a significant impact of both hydrogel-type dose and water dose on onion plant growth, as evidenced by various vegetation parameters. Among the hydrogels tested, Huminsorb® Polyacrylate produced the most favorable outcomes, with treatment T9 (100%, HP, 30 kg/ha) yielding 70.55 t/ha; this represented an increase of 11 t/ha as compared to the 100% ETc treatment without hydrogel application. Moreover, the combination of hydrogel application with 50% ETc water stress showed promising results, with treatment T4 (HP, 30 kg, 50%) producing almost the same yield as the 100% ETc treatment without hydrogel while saving 208 mm of water.

Effects of Nitrogen Application in Recovery Period after Different High Temperature Stress on Plant Growth of Greenhouse Tomato at Flowering and Fruiting Stages

High temperatures have become a severe factor limiting growth and yield for tomatoes (Lycopersicon esculentum Mill.) due to unfavorable, above-optimum temperatures. Temperature and nitrogen application were the main regulatory factors in tomato plant cultivation. This research was undertaken to evaluate the effects of nitrogen application and high temperature on tomato morphology, dry matter accumulation and distribution, root vitality and nitrogen content of the above ground. Tomato variety “Jinfen No. 1” was planted and exposed to 4 day/night temperature levels (25 °C/15 °C as control CKT; 30 °C/20 °C, lightly high-temperature LHT; 35 °C/25 °C, moderate high-temperature MHT; 40 °C/30 °C, severe high temperature SHT) for 7 days after five nitrogen supply levels (N1–N5: 0, 1.3, 1.95, 2.6 and 3.75 g/plant, respectively; 2.6 g/plant is the recommended nitrogen-application rate, as control CKTN4). Within conditions, there was an extremely significant difference (p < 0.01) in all tomato plant parameters and an extremely significant interaction (p < 0.01) between high temperatures and nitrogen supply levels, except for plant height sampling on the 1st day in the recovery period. Dry matter accumulation decreased, and the accumulation rate slowed down. Dry matter accumulation under low nitrogen treatment was higher than in high nitrogen treatment. The proportion of dry matter in leaves decreased, the proportion of dry matter in stems increased and the difference in dry matter accumulation and proportion of dry matter between different nitrogen treatments decreased. Under LHT, the root activity of the tomato was increased under all nitrogen levels, while under MHT and SHT, high nitrogen and low nitrogen supply significantly inhibited root activity. Lightly high-temperature stress can increase root activity, and LHTN4 can increase by 5.15% compared with CKTN4. Appropriate nitrogen application can alleviate the damage caused by high-temperature stress on tomato plants and enhance the resistance of tomato plants, while excessive nitrogen application will aggravate the damage degree of tomato plants. In this study, the optimal nitrogen application rates under CKT-SHT treatment were 2.6, 2.6, 1.95 and 1.3 g/plant, respectively.