Tomato Irrigation Research Articles

Coupled bio-solar photocatalytic treatment for reclamation of water polluted with pharmaceutical and pesticide residues: Impact on tomato irrigation

Reusing reclaimed water for crop irrigation can mitigate water scarcity in agriculture; however, contaminants such as pharmaceuticals and pesticides in wastewater pose risks. This study investigated the impact of a coupled bio-solar photocatalytic treatment on the reclamation of water polluted with seven pharmaceuticals and seven pesticides for irrigation of two tomato crop cycles. Pollutant residues were removed using natural sunlight and TiO2/Na2S2O8 in a pilot plant located in Murcia, Spain. Efficient removal (> 96 %) of all target pollutants was achieved in the effluent after coupled treatment. Reclaimed water was then used to irrigate the tomato crops, and several yield and quality parameters were analysed to evaluate the effects on the harvested tomatoes. No significant differences were observed in the total yield, number and mean fruit weight, size, pericarp firmness, external colour, and nutritional data between the crops irrigated with reclaimed, control, and polluted water. However, differences in the degree of ripeness were observed. None of the investigated pollutants was detected above the limit of quantification in tomato samples irrigated with reclaimed water, except for venlafaxine (0.028 µg kg−1) in the second crop cycle. When the crop was irrigated with polluted water, different pollutant residues were detected in soil (10) and tomato (4) samples. The results suggest that coupled bio-solar photocatalytic treatment is an effective method for reclaiming water polluted with pharmaceutical and pesticide residues, and the reclaimed water can be safely used for tomato irrigation without compromising crop yield and quality.

Drip Irrigation of Tomatoes in Biskra: Water Saving and Economic Profitability

A field survey of thirty tomato growing greenhouses in Biskara region of Algeria was undertaken to find out the kind of the irrigation method being used and to assess their water productivity and economics. 30% of the greenhouses employed drip irrigation (9 farms), 20% (6 farms) utilized furrow irrigation, while the rest used the mixed irrigation. The sowing/transplantation of tomato in greenhouses in the region was carried out from August to October. The production started from March and ended in June. The selling price per kilogram of tomatoes ranged between 25 and 105 Algerian Dinar (DA). Results revealed that greenhouses using drip irrigation had higher water productivity and lower total water requirements. Greenhouses using drip irrigation produced 71.7 tons tomatoes ha-1, which is 33.7% higher than that using furrow irrigation. Drip irrigated greenhouses exhibited maximum water productivity of 20.4 kg m3. Total water consumption in the greenhouses using drip was 3722.2 m3 ha-1 while it was 10248 m3 ha-1 in the furrow irrigated. Average financial returns from the drip irrigated greenhouses were about 36% higher than farms using furrow irrigation.

Optimizing tomato irrigation through deep learning-enabled wireless sensor networks with fuzzy logic

Optimizing tomato irrigation through deep learning-enabled wireless sensor networks with fuzzy logic

Modelling of moisture movement and irrigation scheduling in drip irrigated tomato using CROPWAT and HYDRUS-1D

Modelling of moisture movement and irrigation scheduling in drip irrigated tomato using CROPWAT and HYDRUS-1D

Modeling Irrigation of Tomatoes with Saline Water in Semi-Arid Conditions Using Hydrus-1D

In arid and semi-arid regions like Tunisia, irrigation water is typically saline, posing a risk of soil and crop salinization and yield reduction. This research aims to study the combined effects of soil matric and osmotic potential stresses on tomato root water uptake. Plants were grown in pot and field experiments in loamy-clay soils and were irrigated with three different irrigation water qualities: 0, 3.5, and 7 dS/m. The Hydrus-1D model was used to simulate the combined dynamics of subsurface soil water and salts. Successful calibration and validation of the model against measured water and salt profiles enabled the examination of the combined effects of osmotic and matric potential stresses on root water uptake. Relative yields, indirectly estimated from actual and potential transpiration, indicated that the multiplicative stress response model effectively simulated the measured yields and the impact of saline water irrigation on crop yields. The experimental and modeling results provide information to aid in determining the salinity levels conducive to optimal crop growth. The findings indicate that the selected salinity levels affect tomato growth to varying degrees. Specifically, the salinity levels conducive to optimal tomato growth were between 0 and 3.5 dS/m, with a significant growth reduction above this salinity level. The gradual salinization of the root zone further evidenced this effect. The scenario considering a temperature increase of 2 °C had no significant impact on crop yields in the pot and field experiments.

Effects of food waste and green waste composts on yield and nitrogen‐use efficiency in irrigated tomato crops

AbstractComposts are increasingly used to enhance soil health and agricultural sustainability, but their impacts on nitrogen (N) availability are unclear. In a 3‐year field experiment with subsurface drip‐irrigated tomatoes (Solanum lycopersicum), we investigated the effects of food waste and green waste co‐compost (FW) and green waste compost (GW) on yield, nitrogen‐use efficiency (NUE), nitrate leaching potential, and fertilizer N retention. Various combinations of compost rates (0, 9, or 18 t ha−1) and fertilizer N levels (0%, 70%, 85%, and 100% of the recommended rate) were examined, and 15N‐labeled fertilizer was used. In Years 2 and 3, FW and GW either maintained or increased crop yield compared to no compost when 0% or 70% N was applied; however, lower NUE was observed in the compost treatments compared to no compost when 70% or 85% N was supplied. Postharvest, FW showed greater fertilizer N retention in topsoil than GW and controls, while no difference in nitrate leaching potential was found among treatments, except for Year 2 during which FW exhibited the lowest potential. These results suggest that compost can immobilize fertilizer N, reducing its uptake by crops but enhancing soil retention, potentially acting as an N source or a primer of soil N mineralization. Future research is needed to assess compost's impact on N gaseous emissions and distinguish its dual roles as an N source and a soil N mineralization primer. This is essential for developing nutrient management guidelines to minimize N losses.

Effects of Nutrient Solution Application Rates on Yield, Quality, and Water-Fertilizer Use Efficiency on Greenhouse Tomatoes Using Grown-in Coir.

The yield, quality, and water-fertilizer use efficiency of crops are important parameters for assessing rational water and fertilizer management. For an optimal water and fertilizer system with respect to the nutrient solution irrigation of greenhouse tomatoes using cultivation substrates, a two-year greenhouse cultivation experiment was conducted from 2022 to 2023. Three drip fertigation treatments (T1, T2, and T3) were implemented in the experiment, where nutrient solutions were supplied when the substrate's water content reached 60%, 70%, and 80%. The frequency of nutrient solution applications is based on weighing coconut coir strips in the morning and evening at 7:00 to determine the daily water consumption of plants. Nutrient solutions were supplied when the substrate's water content reached the lower limit, and the upper limit for nutrient supply was set at 100% of the substrate water content. The nutrient solution application was carried out multiple times throughout the day, avoiding the midday heat. The nutrient solution formula used was the soilless tomato cultivation formula from South China Agricultural University. The results show that plant height and the leaf area index rapidly increased in the early and middle stages, and later growth tended to stabilize; the daily transpiration of tomatoes increased with an increase in nutrient solution supply, and it was the greatest in the T3 treatment. Between the amount of nutrient solution application and the number of years, the yield increased with the increase of the amount of nutrient solution, showing T3 > T2 > T1. Although the average yield of the T2 treatment was slightly lower than that of the T3 treatment by 3.65%, the average irrigation water use efficiency, water use efficiency, and partial fertilizer productivity of the T2 treatment were significantly higher than those of the T3 treatment by 29.10%, 19.99%, and 28.89%, respectively (p < 0.05). Additionally, soluble solid, vitamin C, and soluble sugar contents and the sugar-acid ratio of tomatoes in the T2 treatment were greater than those in the other two treatments (p < 0.05). Using the TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) method, it was concluded that the nutrient solution application rate of 70% can significantly increase water and fertilizer use efficiency and markedly improve the nutritional and flavor quality of the fruit without a significant reduction in yield. This finding provides significant guidance for the high-yield, high-quality, and efficient production of coconut coir-based cultivated tomatoes in greenhouses.

Effects of saline-fresh water rotation irrigation on photosynthetic characteristics and leaf ultrastructure of tomato plants in a greenhouse

To reveal the mechanisms of saline-fresh water rotation irrigation that affect the leaf ultrastructure and photosynthetic characteristics of tomato plants and to optimize the strategy of saline water irrigation of greenhouse tomatoes, a two-season tomato experiment with four treatments of saline-fresh water rotation irrigation was conducted in a greenhouse in southern Xinjiang. The four treatments consisted of rotation irrigation with four times saline-fresh water (W1), rotation irrigation with two times saline water and two times fresh water (W2), rotation irrigation with two times fresh water, four times saline water, and two times fresh water (W3), and freshwater irrigation as a control (CK). The three rotation patterns had the same amount of saline water and fresh water, but the rotational interval was different. The results indicated that the saline-alkali stress introduced by saline water significantly reduced the gas exchange parameters of tomato leaves and water use efficiency at the leaf scale, and both stomatal and non-stomatal factors played a key role in limiting leaf gas exchange. The chloroplast granular lamellae structure was disrupted in tomato leaves treated with W1 and W2. Compared with CK, W1 and W2 decreased leaf chlorophyll content by 4.59% and 10.89%, net photosynthetic rate by 26.82% and 40.11%, and yield by 60.62% and 67.63%, respectively. In contrast, W3 presented a relatively intact mesophyll cell structure and relatively high chlorophyll content and photosynthetic efficiency. In W3 treatment, no significant differences were found in the number of fruits per plant (only increased by 8.16% and the yield by 4.03%), while with better quality compared with CK. The results suggested that tomato growth and yield were neither poor nor detrimental when rotated with saline water during the flowering and fruiting stage-fruit expansion stage and freshwater irrigation during other growth stages. W3 can be used as a saline-fresh water rotation pattern for tomato production in greenhouses in arid and saline areas.

Optimal tomato irrigation regime for single-use mechanized harvesting in the Republic of Kalmykia

The purpose of the study is to determine the optimal time for stopping watering tomatoes during one-time mechanized harvesting, for obtaining the maximum yield with high fruit quality in the natural and climatic conditions of the Republic of Kalmykia. The scheme of the field experiment included options for stopping watering when 10, 30, 50% of ripe fruits were reached. The irrigation regime, in relation to single-use mechanized harvesting, was studied when growing tomatoes in the open ground by the seedling method with a drip irrigation. Soil moisture, in the period from full plant survival to maturation of 10% of tomato fruits, was maintained in the range of 80-85% FC in all variants of the experiment. The object of research was a zoned variety of tomato Moryana. The cessation of watering by the time of maturation of 10% of fruits on tomato plantings did not significantly affect the total yield of the crop, while the number of whole commercial tomato fruits amounted to 83.3% versus 81.8% with the cessation of watering at 50% of mature fruits, the proportion of fruits with pedicels decreased from 2.2% to 1.7%, crushed – from 3.6% to 3.2%, with fresh cracks – from 3.0% to 2.7% and fruits with damaged skin from 9.6% to 8.9%, the content of dry substances, the amount of sugars and ascorbic acid increased in the fruits, no negative effect on the growth and development of tomato plants was noted.

Comparison of physiological and biochemical responses of local and commercial tomato varieties under water stress and rehydration

Water scarcity presents an increasingly urgent challenge with global implications for the production of irrigated vegetables. Among these crops, tomatoes stand out as one of the most widely cultivated. Given their vulnerability to water stress, it is crucial to ensure efficient and sustainable water management for tomato irrigation. This study aims to compare physiological and biochemical parameters among three local and three commercial resilient tomato varieties in response to water stress and rehydration. We subjected tomato plants to either two brief periods of water stress (WE1) or one extended period of water stress (WE2), followed by rehydration. Our results did not reveal significant differences in the response to water stress among the varieties, which could be attributed to their respective origins. Following rehydration, the plants quickly returned to their normal physiological values. An exploration of oxidative stress markers revealed that oxidative damage occurred solely during the second episode of water stress in WE1 plants, or towards the conclusion of the prolonged water stress period in WE2 plants. However, after rehydration, tomato plants returned to normal oxidative parameters values, indicating the absence of irreversible damage. Although the severe water stress did not compromise the viability of the plants, all treatments and varieties exhibited a predictable and substantial growth inhibition. In conclusion, the different tomato varieties studied exhibited similar responses to water stress, primarily characterized by the inhibition of gas exchange processes and heightened oxidative stress. Nonetheless, none of the plants suffered irreversible damage from this stress.

Testing sap-flow sensors to predict irrigation of soilless tomato fertigated with saline water

Testing sap-flow sensors to predict irrigation of soilless tomato fertigated with saline water

Effects of Different Salinity Levels in Drip Irrigation with Brackish Water on Soil Water-Salt Transport and Yield of Protected Tomato (Solanum lycopersicum)

The effective exploration and utilization of brackish water resources are crucial to alleviating the scarcity of freshwater in arid regions. This study focused on protected tomato plants and set up four irrigation salinity levels: T1 (2 g·L−1), T2 (4 g·L−1), T3 (6 g·L−1), and T4 (8 g·L−1), with freshwater irrigation as a control (CK). The aim was to investigate the effects of continuous brackish water irrigation on soil water-salt transport and tomato yield. The outcomes highlighted that the moisture content in different layers of soil exhibited a “high in the middle, low at both ends” pattern, with the primary accumulation of soil moisture occurring at the 40 cm depth. The range and moisture content of the soil wetted zone increased with elevated salinity levels. Under continuous brackish water irrigation, the range of the soil wetted zone expanded further for the autumn crops, and the moisture content significantly increased compared to the spring crops. The concentration of soil salt gradually decreased with increasing soil depth, exhibiting greater levels in the 0–20 cm layer compared to the 40–80 cm layer. The average salt concentration in the soil at the end of the growth period was significantly higher than before transplantation, and this phenomenon became more pronounced with increasing salinity levels. Initial irrigation with brackish water with a salinity level of 2–4 g·L−1 promoted the growth of the tomatoes planted in the spring and the plant height and stem diameter reached the peak values of 1.68 m and 1.08 mm for the T2 treatment, respectively, which were 7.1% and 9.2% higher than that of the CK treatment, ensuring efficient yield and water usage. However, continuous irrigation with brackish water with a salinity level of 2–4 g·L−1 inhibited the growth and yield of the tomatoes planted in autumn, while the T1 and T2 treatments only yielded 24,427.42 and 16,774.86 kg·hm−2, respectively, showing a decline of 32.2% and 46.1% compared to the yields of the spring season. Considering the soil water-salt and yield indicators, under the conditions of non-continuous brackish water irrigation, using water with a salinity level of 2–4 g·L−1 is recommended for drip irrigation of protected tomatoes.

Using AquaCrop model to derive deficit irrigation schedules for improved irrigation water management for tomato production in Zimbabwe

Increasing scarcity and unreliability of rainfall, and the absence of irrigation schedules are challenges to decision-making, particularly for viable tomato (Lycopersicon esculentum Mill) production in Zimbabwe. The objective of this study was to determine water requirements of tomato as a basis for developing generic calendar guidelines for a more efficient irrigation management in Harare, Zimbabwe. We explored the options of improving the traditional, dry and supplementary wet season irrigation practices. By considering the archived climate data of thirty years (1991-2021) for Harare; and model-simulated consumptive water use from 2014 to 2017 at Thornpark Research Station, together with the crop and soil characteristics; and the irrigation method; an irrigation calendar was developed using the AquaCrop model 5.0. The improved irrigation schedule for dry season tomato cultivation at 60% ETc, resulted in water use of 471.6 mm, with a yield of 3.40 t ha-1; compared to water use of 820 mm and a yield of 1.118 t ha-1; for the wet season. Through this model, we have been able to estimate the time interval between the previous irrigation and the next irrigation for any date in the growing season. Therefore, year-round irrigated tomato production may be feasible with an added yield advantage of 2.28 t ha-1 obtainable using water and rainy periods.

USING THE WATER STRESS INDEX FOR TOMATO IRRIGATION CONTROL

The temperature of the leaf surface of plants can be used as an indicator of the water stress of agricultural crops. Since plant temperature is affected by weather factors, it is usually expressed through the crop water stress index (CWSI). To calculate the CWSI, two input parameters must be known that relate plant temperature under and without maximum water stress to the water vapor pressure deficit. These basic equations are specific to each culture and locale. Many studies on the definition of CWSI and basic dependencies for tomatoes have been conducted abroad, such a study has not yet been conducted in Ukraine. The purpose of the research is to establish CWSI values and basic equations that are needed for the purpose of watering tomatoes in the south of Ukraine under subsurface drip irrigation. The paper presents the results of determining the theoretical and empirical water stress index of tomatoes under subsurface drip irrigation. The research results confirm that the water stress index can be used to plan the irrigation of tomatoes both independently and in combination with other methods to increase the accuracy of decision-making. An analysis of the daily dynamics of the CWSI was carried out, according to the results of which it was established that in the morning hours the water stress index on average during the observation period was almost 0, then, as the intensity of solar radiation increased, the CWSI also increased and reached its maximum value (1,08) at 20:00. The correlation coefficient between the water stress index and the intensity of solar radiation was 0,63. The relationship between irrigation rate, soil moisture, change in plant stem diameter, and CWSI was established, the correlation coefficients are -0,60, -0,55, and -0,51, respectively. Theoretical and imperial methods estimate CWSI equally, there is a high correlation between both methods (r=0,92). It is necessary to prescribe irrigation or increase the irrigation rate according to the theoretical and empirical methods of determining CWSI, respectively, for its values of 0,3 and -2,2. The empirical method of calculating CWSIE using the resulting equations is easier to use. The CWSI values obtained for tomatoes in this study are closely correlated with the other irrigation methods.

Irrigation Scheduling in Processing Tomato to Save Water: A Smart Approach Combining Plant and Soil Monitoring

The gradual reduction of water reserves for irrigation has become a worldwide concern. To improve the irrigation of processing tomato, we conducted a study to evaluate a system that monitors both plant water status and soil moisture levels (PlaSoMan) compared to an evapotraspirometric method (IrriMan) and an empirical farmer’s management (FarMan) in a two-year field trial. The results showed that PlaSoMan saved around 30% and 7.5% of water, with a yield loss of only 10% and 2.5% compared to FarMan and IrriMan, respectively. Thus, PlaSoMan showed satisfactory irrigation water use efficiency (IWUE) over the two years. Moreover, IrriMan and PlaSoMan had lower blue water requirement (BWR) values than FarMan. Finally, PlaSoMan reached the highest value of the yield quality indicator, which combined total yield and brix degree. Thus, the new system, which assesses both plant water status and soil moisture levels, appears to be associated with high-quality and water-friendly tomato production representing an efficient solution for areas with limited water resources.

Data-Driven Modelling of Soil Moisture Dynamics for Smart Irrigation Scheduling

In the face of increasing water scarcity and uncertainties of climate change, improving crop water use efficiency and productivity, while minimizing negative environmental impacts, is becoming crucial to meet the surging global food demand. Smart irrigation has a potential of improving water use efficiency in precision agriculture especially when efficient irrigation control strategies are adopted. Conventionally, irrigation systems rely on heuristic methods to schedule irrigation which either leads to over-irrigation or under-irrigation. This influences the crop physiological characteristics as well as the water use efficiency. To tackle this menace, model-based irrigation management has been overemphasized. A closed-loop irrigation control strategy relies on a mathematical model of the system for irrigation scheduling decisions. In this study, a data-driven approach was used to learn soil moisture dynamics from a drip irrigated tomato in an open field agricultural system. A total number of 9674 data samples were collected using an ATMOS41 weather station, TERROS 12 soil moisture sensor and a YFS-201 flow sensor for crop evapotranspiration and precipitation, soil moisture and irrigation volumes respectively. Data driven modelling was then performed using the system identification toolbox in a MATLAB environment. The model formulation was a multi-input single-output (MISO) system with reference evapotranspiration, irrigation and rainfall as inputs and soil moisture as the output. Different model structures including transfer functions, state space models, polynomial models and ARX models were evaluated. Model performance was evaluated using the mean square error (MSE), final prediction error (FPE) and estimated fit of the model approaches. Simulation results indicate that the soil moisture dynamics model provides a satisfactory approximation of the process dynamics with a state space model giving an estimated fit of 97.04 %, MSE and FPE of 1.74×10−7 and 1.75×10−7 respectively. This model will be used to design a model predictive controller for smart irrigation scheduling in open field environmental conditions.

Simulation of Soil Water Movement and Root Uptake under Mulched Drip Irrigation of Greenhouse Tomatoes

Three irrigation treatments were set up in northeast China to investigate soil water movement and root water uptake of greenhouse tomatoes, and the collected experimental data were simulated by HYDRUS-2D. The computation and partitioning of evapotranspiration data into soil evaporation and crop transpiration was carried out with the double-crop coefficient method. The HYDRUS-2D model successfully simulated the soil water movement, producing RMSE ranging from 0.014 to 0.027, an MRE ranging from 0.062 to 0.126, and R2 ranging from 79% to 92%, when comparing model simulations with two-year field measurements. Under different water treatments, 83–90% of the total root quantity was concentrated in 0–20 cm soil layer, and the more the water deficit, the more water the deeper roots will absorb to compensate for the lack of water at the surface. The average area of soil water shortage in W1 was 2.08 times that in W2. W3 treatment hardly suffered from water stress. In the model, parameter n had the highest sensitivity compared with parameters α and Ks, and sensitivity ranking was n &gt; Ks &gt; α. This research revealed the relationships between soil, crop and water under drip irrigation of greenhouse tomatoes, and parameter sensitivity analysis could guide the key parameter adjustment and improve the simulation efficiency of the model.

Dynamic Optimization of Greenhouse Tomato Irrigation Schedule Based on Water, Fertilizer and Air Coupled Production Function

A vegetable water production function has been one of the most significant parameters to improve the use efficiency and economic benefit of agricultural water in the greenhouse. Meanwhile, aerated irrigation unlocks the high yield potential for greenhouse crop production. Thus, water, fertilizer and air coupled production function is proposed for the optimization of the irrigation scheme during the greenhouse tomato growth period. Two seasons of greenhouse tomato experiments were conducted under aerated subsurface drip irrigation (ASDI). There were three nitrogen application rates (N1, 120 kg ha−1; N2, 180 kg ha−1; N3, 240 kg ha−1) and three aeration rates with dissolved oxygen (DO) in irrigation water (A2, 15 mg L−1; A3, 40 mg L−1 and A1, 5 mg L−1 in the non-aeration treatment) in the first crop season, while three irrigation rates of soil moisture content (W1, 50–60% field capacity; W2, 60–70% field capacity; W3, 70–80% field capacity) and two aeration rates with DO in irrigation water (25 mg L−1 and 5 mg L−1) in the second crop season. The potential yield function of tomato was constructed, and the water sensitivity index was resolved. The production function of greenhouse tomato under water, fertilizer, and air coupled irrigation was established based on the Jensen function. The water allocation scheme under multiple irrigation quotas was optimized by the dynamic programming (DP) method. The results showed that with the elapse of crop growth stages, the cumulative curve of the water sensitivity index showed an S-shaped curve, which first rose slowly and then fast, and eventually tended to be stable. The optimized irrigation increased the yield by 4.25% averagely compared with the irrigation method of fixed moisture content interval, while the crop yield in the optimized ASDI increased by 26.13% compared with non-aeration treatment. In summary, the optimal combination was the aeration rate DO of 24.55mg L−1 in irrigation water and nitrogen application rate of 281.43 kg ha−1, and the irrigation quota of 420 mm. The net yield increased by 11,012 USD ha−1 in a single crop season when compared with the non-aeration treatment. The results would provide a reference method for the optimization of technical parameters of water—fertilizer—air coupled irrigation.

Yield, water productivity and economic return of deficit-drip-irrigated tomatoes in Kaduna (Nigeria)

Compared to gravity flow systems, pressurized drip irrigation provides more efficient control of the amount of water applied, better irrigation uniformity, and a higher initial capital and operation costs. Hence, an economic analysis is required to determine its profitability over a projected time period. Field experiments were conducted in Afaka (Kaduna, Nigeria), during two dry seasons of 2018 and 2019 to determine the effect of regulated deficit irrigation on the yield, crop water productivity, and projected economic returns of UC 82B tomatoes under pressurized drip irrigation. The economic returns were evaluated using the benefit-cost ratio, net present values, and payback period analyses. The highest fresh fruit yield (19.0 t/ha) was obtained in the full irrigation treatment (T1), while the highest crop water productivity (4.94 kg/m3) was obtained in the deficit treatment with full irrigation at the vegetative and flowering stages followed by 60% of reference evapotranspiration at maturity (T7). The project was found to be profitable over the projected years, with benefit-cost ratios of 1.90 and 1.69; payback periods of 2.7 and 3.2 years for T1 and T7, respectively. The full irrigation of tomatoes was therefore found to be more economical than deficit irrigation in the area, with water not being considered as a limiting factor in terms of costs. Gravity drip irrigation was recommended to reduce the pumping cost of irrigation and thereby increase the profit margin.

Proper Deficit Nitrogen Application and Irrigation of Tomato Can Obtain a Higher Fruit Quality and Improve Cultivation Profit

Faced with severe global shortage of water and soil resources, studies on the integrated effect of water and nitrogen on tomato cultivation are urgently needed for sustainable agriculture. Two successive greenhouse experiments with three irrigation regimes (1, 2/3, 1/3 full irrigation) and four nitrogen levels (1, 2/3, 1/3, 0 nitrogen) were conducted; plant growth, fruit yield and quality were surveyed; and comprehensive quality and net profit were evaluated. The results show that water and nitrogen deficit decreased plant growth, evapotranspiration and yield while increasing production efficiency and fruit comprehensive quality. An antagonism effect from water and nitrogen application was found in tomato yield, organic acid, solids acid ratio, vitamin C and lycopene, whereas synergistic impact was observed in total soluble solids content. Water deficit had more significant effect on tomato yield and fruit quality parameters compared with that of nitrogen deficiency. Synthesizing the perspectives of yield, quality, resource productivity, market price index and profits, 1/3 full irrigation and 2/3 full nitrogen was the best strategy and could be recommended to farmers as an effective guidance for tomato production.