Water Productivity Values Research Articles

Water productivity and date palm production: a field study in Biskra Region

In southern Algeria, agriculture is mainly based on groundwater irrigation, leading to significant water consumption, Improving water productivity in field-scale irrigation is critical for sustainable water management and the protection of this valuable resource. In the present study, to analyze water productivity, data were collected on the volumes of irrigation water applied and the resulting yields from 24 farmers through a survey questionnaire during the 2022-2023 agricultural season water productivity for date palm cultivation was evaluated in Biskra region of Algeria. The study found that water productivity values ranged from 0.4 to 1.1 in kg m-3 with an Average of 0.83 kg m-3, consequently, producing one kilogram of dates requires 1220.35 liters of water. Based on the findings of this study, it can be concluded that the water productivity of date palms was moderate compared to the results of other studies conducted in various regions around the world. This research highlights the critical need for strategies to enhance water-use efficiency, including the implementation of advanced irrigation technologies and improved management practices.

Impacts of Adding Porous Media and Phase Change Material on Performance of Solar Water Distiller System Under Iraq Climatic Condition: An Experimental Study

ABSTRACTThis current investigation involves an experimental inspection of adding porous medium and phase change material (PCM) above the absorber surface to enhance the performance of a single slope and single basin solar water distiller system. To demonstrate the effectiveness of adding porous medium and PCM, the performance of the modified system and conventional system is compared under similar operating conditions. The system that uses porous medium and PCM is called MSS‐FPP, whereas the conventional system is called MSS‐F. Rectangular fins are fixed above the absorber plate for both models. For MSS‐FPP model, three different types of porous medium (stones, nuts, and black glass balls) are used in addition to paraffin wax filled inside circular tubes as a PCM. The data are collected in November and December 2023 in Mosul City, Iraq. The experiments are carried out under different water depths. The findings confirm that the performance of MSS‐FPP model is better than MSS‐F model by 41.32% (for water depth 3 cm) and 30.61% (for water depth 5 cm). The results also indicated that the water productivity of MSS‐FPP model is higher than MSS‐F model by 41.67% (for water depth 3 cm) and 30.65% (for water depth 5 cm). For MSS‐FPP model, the maximum water productivity and efficiency are obtained when using black glass balls as compared to nuts and stones types, where the highest water temperature and water productivity values are found equal 54°C and 1.01 kg/m2 for water depth 3 cm. The enhancement in the performance of modified solar water distiller system (MSS‐FPP) shows that using a porous medium and PCM has considerable impacts on the evaporation rate, heat exchange, and rate of heat transfer.

Water productivity in Vitis vinifera L. cv. Alvarinho using dual crop coefficient approach

Water productivity (WP) measurement determines the efficiency of water use by assessing the ratio of the crop yield to the amount of water used in production. The objective of this study was to identify the optimal irrigation treatment for Vitis vinifera L. cv. Alvarinho with ground cover in Northern Portugal, with a focus on water productivity. Two irrigation treatments (full irrigation—FI; deficit irrigation—DI) and a control (rainfed—R) were considered. The FI strategy represented the standard irrigation carried out by the vinegrower, based on the water availability and their experience. The cover crop was a variable factor, evaluated in terms of both height and density, both within the crop row and between the rows. In each of the treatments, the available soil water content (ASW) was measured in eight locations in the field throughout the growing season using a capacitive probe (Diviner 2000) previously calibrated. These measurements were used to calibrate the SIMDualKc model, which employed the dual crop coefficient approach. The successful calibration of the model, carried out with treatment R in 2018, was evidenced by the strong correlation between the ASW measured through the capacitive probe and that simulated by SIMDualKc (b=0.988 and r2=0.995). After the model’s calibration, the separation between the transpiration and evaporation components was determined. The maximum transpiration during the growing season was observed in the full irrigation treatment. In this context, the study proceeded to apply the soil water balance components and transpiration generated by the model in the calculation of the WP. The fruit yield productivity was determined by accounting for the total water use in the growing season. The total water used was calculated by combining the volumes of water applied for irrigation and precipitation and the soil water extracted during the growing season by crops and cover crops. The deficit irrigation strategy showed the best performance in both years, with WP values of 3.31 and 1.81 kg m−3 for the years 2018 and 2019, respectively. Therefore, the study concluded that deficit irrigation proved to be the most effective irrigation strategy in terms of water productivity and crop water use efficiency (WUEc).

Gravel Mulching Significantly Improves Crop Yield and Water Productivity in Arid and Semi-Arid Regions of Northwest China: Evidence from a Meta-Analysis

In the arid and semi-arid regions of Northwest China, periodic rainfall deficits, high field evaporation, limited freshwater resources, and high irrigation costs restrict crop yield and water productivity (WP). Gravel mulching (GM), a traditional agricultural tillage management practice widely used in arid and semi-arid regions, improves crop yield and WP. However, the combined impacts of GM on crop yield and WP are unclear. This study aimed to examine the effects of GM on crop yield and WP under different factors and to find the most critical regional factors and gravel characteristics that affect crop yield and WP. To quantitatively assess the impact of GM on crop yield and WP, this study performed a meta-analysis, a regression analysis, and a path analysis of 185 yield comparisons and 130 WP comparisons from 30 peer-reviewed scientific reports. This study found that GM significantly increased crop yield and WP by an average of 29.47% and 28.03%, respectively. GM was reported with the highest response percentages (I) of crop yield and WP in regions whose average annual precipitation (AAP) was 200–400 mm, average annual temperature (AAT) was 0–9 °C, and altitude (A) was >1000 m. Overall, AAP, AAT, and A had significant effects on the I of crop yield (p < 0.001), but AAT and A had an insignificant impact on the I of crop WP (p > 0.05). Gravel size (GS), the amount of gravel mulching (AGM), the degree of gravel mulching (DGM), and the gravel mulching thickness (GMT) had a significantly positive impact on crop yield and WP (p < 0.05). The stepwise multiple linear regression analysis results indicated that the primary regional factors influencing yield were AAT and A, contributing 43.14% and 53.09%, respectively. GMT and GS were identified as significant gravel characterization factors impacting yield, contributing 82.63% and 17.37%, respectively. AAP and GMT were the main regional factors and gravel characterization factors affecting WP. Furthermore, the I values for cash crop yield and WP were higher than that for food crops, and moderate fertilization and irrigation would increase the I values of yield and WP. The benefits of GM are strongly correlated with the planting year. This study’s results show that GM generally improves crop yield and WP, although the extent of this impact varies based on different conditions. These findings are not only useful in relation to their direct applicability to other countries worldwide but also due to their potential to provide new ideas for agricultural practices in similar crop-growing environments.

Individual or successiveseed priming with nitric oxide and calcium toward enhancing salt tolerance of wheat crop through early ROS detoxification and activation of antioxidant defense

Despite the considerable efforts reported so far to enhance seed priming, novel ideas are still needed to be suggested to this sustainable sector of agri-seed industry. This could be the first study addressing the effect of nitric oxide (NO) under open field conditions. The impacts of seed redox-priming using sodium nitroprusside (SNP) and osmo-priming with calcium chloride (CaCl2), both applied individually or successively, were investigated under salinity stress conditions on wheat plants (Triticum aestivum L.). Various parameters, including water relations, growth, yield, photosynthetic pigments, and antioxidant activities (enzymatic and non-enzymatic), were recorded to assess the outcomes of these priming agents on mitigating the negative impacts of salinity stress on wheat plants. Water consumptive use (ETa) and irrigation water applied (IWA) decreased with seeds priming. Successive priming with SNP + CaCl2 induced the greatest values of crop water productivity (CWP), irrigation water productivity (IWP), seed index, grain yield and grain nitrogen content.Under salinity stress, the dry weight of plants was decreased. However, hydro-priming and successive chemical priming agents using combinations of calcium chloride and sodium nitroprusside (CaCl2 + SNP & SNP + CaCl2) preserved growth under salinity stress.Individual priming with sodium nitroprusside (SNP) and calcium chloride (CaCl2) resulted in the lowest recorded content of sodium in the shoot, with a value of 2 ppm. On the other hand, successive priming using CaCl2 + SNP or SNP + CaCl2 induced the contents of potassium in the shoot, with values of 40 ppm and 39 ppm, respectively. Malondialdehyde decreased in shoot significantly withapplicationof priming agents. Successive priming with CaCl2 + SNP induced the highest proline contents in shoot (6 µg/ g FW). The highest value of phenolics and total antioxidants contents in shoot were recorded under successive priming using CaCl2 + SNP and SNP + CaCl2.Priming agents improved the activities of ascorbate peroxidase and catalase enzymes. The successive priming improved water relations (ETa, IWA, CWP and IWP) and wheat growth and productivity under salinity stress more than individual priming treatments.

Determination of threshold crop water stress index for sub-surface drip irrigated maize-wheat cropping sequence in semi-arid region of Punjab

A thorough understanding of how crops respond to water stress is essential for effective irrigation management under changing climate conditions and declining water resources. Amongst the various methods of irrigation, crop water stress index (CWSI)-based irrigation is popular due to its non-invasive techniques that require less data and can precisely indicate the severity of crop water deficiency. The present study focuses on establishing the upper- and lower-baselines of canopy-air temperature difference (Tc-Ta) for the estimation of the CWSI and to determine the CWSI threshold for maize and wheat crops. The upper- and lower-baseline of (Tc-Ta) was established using the relationship between (Tc-Ta) and vapor pressure deficit (VPD) for different irrigation treatments such as 60 %ETc, 70 %ETc, 80 %ETc, 90 %ETc, and 100 %ETc with irrigation interval of 1-day, 2-days, and 3-days. The study showed that the baselines varied with the growth stages of the crop and with irrigation treatments and reached the maximum in Anthesis and Silking growth stage for wheat and maize, respectively. The threshold of CWSI was estimated by developing a relationship between the normalized values of grain yield (GY) and irrigation water productivity (WPI). For the Rabi wheat, a quadratic correlation was identified between CWSI and WPI (r2 = 0.89), and GY (r2 = 0.93). Similarly, for Kharif maize, a quadratic relationship was noted between CWSI and both WPI (r2 = 0.75) and GY (r2 = 0.85). From the study, it was found that the CWSI thresholds of Rabi wheat and Kharif maize are 0.29 and 0.31, respectively. Based on the study, it can be concluded that by utilizing the thresholds for a winter wheat-summer maize cropping system, high GY and WPI can be achieved.

AquaCrop Model for Evaluation of the Water Productivity of Bread Wheat has Affected Modern Irrigation System and Water Salinity in Sandy Soil

AquaCrop is a very famous model in the world for evaluating the crop water productivity. FAO has developed the AquaCrop model as a leading and powerful scientific tool for simulating the response of different field crops to managing quantitative and qualitative irrigation. Two field experiments were carried out during winter seasons 2020/2021 and 2021/2022 at the Research and Production Station, National Research Centre, El-Nubaria, El-Behira Governorate, Egypt. to evaluate yield and yield component for two bread wheat varieties (Giza 171 and Misr 1) under sprinkler and drip irrigation systems with using four concentrations of water salinity irrigation. A split-plot design with three replications was used. Wheat were randomly distributed in the main plots while, while water salinity treatments occupied the sub-plots in both seasons. Results found that the simulated and observed values of water productivity were rather well in agreement for the salinity water levels treatments SWLT. This means that differences in canopy cover CC, yield and water productivity of bread wheat crop had significant effect on the calibration results. There is an inverse relationship between the water productivity and salinity water levels treatments and bread wheat varieties, while a direct correlation was found between water productivity and irrigation systems. It could be concluded that using sprinkler irrigation systems with S1 and S2 of SWLT and Misr 1 varitey, and drip irrigation system with S1 and S2 of SWLT and Misr 1 varitiey. the maximum of water productivity due to that there is a direct relationship between the study factors, the characteristics of the canopy cover growth and yield of the bread wheat plants, the more measured values will be simulated by the Aquacrop model.

Combined effect of silicon and nitrogen doses applied to planting furrows on sugar, biomass and energy water productivity of sugarcane (Saccharum spp.)

Brazil has the largest cultivated area for sugarcane in the world, with a predominance of rain-fed production systems (64%) and marginal areas that are subject to frequent water deficits. The remaining 36% under cultivation is equipped with irrigation systems; however, a significant portion of these irrigation systems (76%) is dedicated to crop maintenance. Their primary purpose is to provide water for initial plant maintenance during planting and regrowth of ratoons, which helps to alleviate drought stress caused by water scarcity during dry periods. The remaining 24% of the irrigated sugarcane production areas use deficit and full irrigation strategies to partially (50%) and fully (100%) meet the plants’ water demands, respectively. Therefore, a large part of the cultivated area for sugarcane in Brazil is subject to a water deficit at one or more stages of the crop's development cycle, which can retard plant growth, nutrient use and productivity. One potential strategy for mitigating these harmful effects is the application of silicon (Si) in the furrow at planting, which can also increase crop water productivity (WPc). The objective of this research was to determine the effects of different applications of Si and nitrogen (N) on WPc, in terms of sugar (SWPc), biomass (BWPc) and energy (ENWPc) for sugarcane crop. The research was conducted at the University of São Paulo (USP/ESALQ), Piracicaba, São Paulo State, Brazil. The experimental design involved randomized blocks, with four blocks and 12 treatments. The treatments consisted of three applications of Si, 175, 350 and 525 kg·ha−1 and four N treatments of 15, 30, 60 and 90 kg·ha−1. Biometric responses, effects on juice quality, and indices related to yield and WPc were determined. The water consumption and agricultural yield (AY) of sugarcane were clearly influenced by the treatments. The lowest water consumption was obtained with the 15Nx350Si treatment, 561 mm per year. The treatment with the highest AY value was 60Nx350Si (162.3 Mg·ha−1). The SWPc, BWPc and ENWPc of the sugarcane crop were affected by the different application rates of N and Si. In general, the highest average WPc values were obtained with the 15Nx350Si treatment (SWPc=2.6 kg·m−3, BWPc=10 kg·m−3 and ENWPc=224.5 MJ·m−3). The different N and Si treatments did not significantly affect biometric variables (except for fresh biomass and leaf area) or juice quality; therefore, Si application did not compromise the quality of the end-product.

Novel integration of thermoelectric distiller with direct contact membrane distillation

A thermoelectric distiller (TED) integrated with a direct contact membrane distillation (DCMD) unit was proposed and numerically investigated. The mathematical models of the hybrid TED--–DCMD system were developed and validated. In the proposed hybrid system, the TED provides the heating demand of the DCMD desalination unit in four novel configurations of TED-DCMD integration. The first configuration integrates the TED-DCMD by adding a DCMD heat exchanger coil inside the condensation tank of a TED, while the second configuration involves two TED condensation tanks with each tank containing a DCMD heat exchanger coil. The third configuration also consists of two TED tanks with an external heat exchanger where thermal energy from the TED produced water is transferred to the DCMD feed stream. The fourth configuration is a modification of the second configuration with a thermal recovery from TED produced water for inlet feed water preheating. To investigate the performance (distillate productivity, specific energy consumption, coefficient of performance, and ratio of TED productivity) of each integrated TED-DCMD configuration, the effects of different operating parameters such as DCMD feed flow rate, TEM current, number of TEMs, and TED produced water temperature were examined. Findings indicated that the third configuration is the most energy efficient, with specific energy consumption (SEC) reaching a minimum value of 217 kWh/m3 at low current operation of 2.1 A, and feed flow rate of 4.0 L/min for 8.0 TEMs in the TED. A maximum freshwater productivity and COPh of 2.74 kg/s and 3.24, are attained by the 4th and 3rd configurations, respectively. Results also indicated that elevating the current input encourages higher water productivity. Meanwhile, higher values of SEC and water productivity are attained when operating TED at saturation temperature.

Water productivity and growth parameters of Fawn-tall fescue and Tekapo-orchard grass under deficit irrigation in arid zones.

This study aimed to determine the drought stress response of Fawn-tall fescue and Tekapo-orchard grass and investigate a drought stress resistance marker. Grass genotypes were grown under four Irrigation treatments I1 equivalent to 0.3 standard crop evapotranspiration (ETc), I2 equivalent to 0.65 ETc, I3 equivalent to 0.75 ETc, and I4 equivalent to 1.2 ETc. Plant height, fresh weight, dry weight were measured and the Water productivity (WP) were calculated. The results showed a reduction in the growth of both grass genotypes as the drought stress increased as indicated by the shorter plants and reduction in fresh and dry weight. However, the WP results showed that the Fawn-tall fescue endured the drought stress better than the Tekapo-orchard grass as indicated by the constant values of the plant WP across the tested irrigation treatments. The results was confirmed by the amplification of dehydrin genes where Fawn-tall fescue was found to be homozygous for dehydrin genes.

Estimating ETO and scheduling crop irrigation using Blaney–Criddle equation when only air-temperature data are available and solving the issue of missing meteorological data in Egypt

Accurate assessment of evapotranspiration is essential for crop irrigation planning. In developing countries and given the cost of evaluating evapotranspiration based on the Penman-Monteith equation, this research is an attempt to provide a simple equation that depends only on temperature to estimate evapotranspiration and serve as an alternative method to FAO56-PM when only air temperature data are available and the problem of missing meteorological data is solved. Four reference methods for evapotranspiration (ET) were compared under the local climatic conditions of the El-Nobaria region in northern Egypt. The Blaney–Criddle method was found to have the highest correlation with the FAO56-PM method. Using the simple equations to calculate ETo for irrigation scheduling of peanuts had a positive effect on the yield and yield components of peanuts. The highest productivity value was obtained when the Blaney–Criddle equation was used to estimate peanut irrigation scheduling, while equation resulted in lower productivity. When the equation was used, the differences in productivity between the equations were highly significant. It is worth noting that when the Blaney–Criddle and Thorthwaite equations were used, followed by the FAO56-PM equation, the superiority of the water productivity value became evident, as the increase in nutrient concentration in the root zone led to increased nutrient uptake, resulting in an increase in the productivity of peanut yield, oil and protein.

Evapotranspiration and Yield Impact Tools for More Water-Use Efficient Alfalfa Production in Desert Environments

Drought and climate change have decreased water availability for agriculture, especially in the desert of southwestern USA. Efficiency enhancements in irrigation management aimed at conserving water are key to adjust to limits in water supply, improve profitability and sustainability of alfalfa production in arid and semiarid areas. This study intended to conduct a field-scale analysis to develop yield and ET estimation tools for the effective use of irrigation water in a desert alfalfa production system. Extensive data collection and trials were carried out over three years in nine fully irrigated commercial alfalfa fields in the low deserts of California. The seasonal crop water consumption measured using the residual of energy balance method varied from 1381 mm to 1596 mm across the experimental sites and crop seasons. Variable seasonal dry mater (DM) yields ranged from 23.01 Mg ha−1 to 29.90 Mg ha−1. The results indicated that the first five cuttings each year were the most productive cuttings with a mean DM value ranged between 3.29 (cut 1) and 4.21 (cut 4) Mg ha−1 but declined in later cuttings. An average annual water productivity (WP) value of 17.0 kg ha−1 mm−1 was determined across the sites varying from 15.5 to 18.9 kg ha−1 mm−1. The findings suggested that one may lose up to 1.44 Mg ha−1 alfalfa yields with moderate summer deficit irrigation strategies, using 40% less water applied than full irrigation practices over the summer period of July–September. A more severe summer water deficit, with no irrigation event over the summer period of July–September may result in a potential water savings of 0.234–0.246 (ha·m) ha−1 and 19–21% seasonal yield losses in the desert environment. This study describes the seasonal yield pattern, the crop water use-production function, and the crop coefficient values for various harvest cycles over the crop season. These tools may assist farmers to quantify water savings and estimate yield losses for more accurate and effective irrigation management strategies to meet water conservation objectives and for the resiliency of alfalfa production in the desert region.

Boosting stepped solar still system efficiency with affordable natural energy absorbers

In this study, we examined a solar still made of galvanized iron that was exposed to a solar simulator with a light intensity of 904 W/m2. We used iron ore, granite, and sponge as photoabsorbers on the surface of the stairs to enhance the interaction between air and water. This increased steam production and made the process of generating fresh water more cost-effective. We conducted experimental tests in different modes at three mass flow rates: 0.195, 0.134, and 0.1 kg/min.The results showed that increasing the mass flow rate of the inlet feed water decreased the production of drinking water and the evaporation efficiency in all three modes. Furthermore, iron ore effectively stored solar radiation energy, resulting in increased evaporation rates. The highest drinking water production was achieved using iron ore at a mass flow rate of 0.1 kg/min, with a value of 715 ml/min. In comparison, granite, sponge, and the base state had drinking water production values of 630, 555, and 515 ml/min, respectively. Cost analysis revealed that the lowest mass flow rate of the feed water led to the lowest product price when using iron ore (0.07$/liter), which is comparable to techniques reported in the literature.

Tomato Yield Responses to Deficit Irrigation and Partial Root Zone Drying Methods Using Biochar: A Greenhouse Experiment in a Loamy Sand Soil Using Fresh and Saline Irrigation Water

The impacts of regulated deficit irrigation (RDI) and partial root zone drying irrigation (PRD) on water productivity (WP), crop water response factor (Ky), and yield of tomato crop (Solanum lycopersicum) were explored in this study using fresh (0.9 dS m−1) and saline (3.6 dS m−1) water under greenhouse conditions. RDI had four ETc (crop evapotranspiration) levels, i.e., 40, 60, 80, and 100%. PRD adopted 100% ETc for all treatments with changes in its application time (first, second, third, and fourth growth stages). Biochar pyrolyzed at 450–500 °C and added at rate of 4%. The results revealed that the Ky ranged between 0.21 and 0.37, indicating that tomato can tolerate a shortage of irrigation water. The highest value of WP (191 kg m−3) was found in 40% ETc using fresh water with biochar. The highest yield (20.0 kg m−2) was obtained with the application of 100% ETc with fresh water and biochar. Biochar application did not result in favorable yields with saline water due to its high salinity (7.8 dS m−1). The use of PRD in the fourth stage with biochar and fresh water led to the highest yield (20.6 kg m−2). Finally, this study recommends the application of biochar only when fresh irrigation water is available in adequate amounts.

Effects of Deficit Irrigation and Anti-Stressors on Water Productivity, and Fruit Quality at Harvest and Stored ‘Murcott’ Mandarin

A two-year experiment using ‘Murcott’ mandarin (Citrus reticulata) was conducted under deficit irrigation (DI) strategies with an anti-stressor application and then stored. The three DI regimes were 70% crop evapotranspiration (70% ETC), 85% ETc, and full irrigation (100% ETc). Anti-stressor treatments consisted of a foliar application of either sodium nitroprusside (SNP), selenium nanoparticles (NanoSe), microalgae (Spirulina platensis), or a non-treated control. Mean water productivity values were highest for trees at 70% ETc and 85% ETc when they were sprayed with microalgae, which was 42% and 51% greater, respectively, compared to control trees at 100% ETc, but only 6.5% and 13% greater, respectively, compared to trees sprayed with microalgae at 100% ETc. Trees sprayed with microalgae at 100% ETc or 85% ETc had the highest and second-highest fruit yields. The percentage of fruit water loss after 15 d storage at either 1.5 °C + 90% RH or 16 ± 2 °C + 60–65% RH was reduced at all DI regimes when trees were sprayed with an anti-stressor compared to control trees at the same DI regime. Trees sprayed with 150 μmol L−1 SNP had the only fruit peel that maintained the carotenoid content after cold storage. In general, trees sprayed with SNP were most successful at each DI regime for reduced Malondialdehyde (MDA), but after 15 d of cold storage, only trees sprayed with 150 μmol L−1 SNP at 85% ETc or 100% ETc and/or trees sprayed with NanoSe at 70% ETc had fruit that maintained low MDA content. Catalase and peroxidase enzyme activities and proline content were enhanced when trees were sprayed with 150 μmol L−1 SNP during DI strategies. This study demonstrates the effectiveness of deficit irrigation combined with anti-stressor applications to improve water productivity, fruit yields, and post-storage quality of ‘Murcott’ mandarin trees. These findings offer valuable insights into sustainable citrus production under limited water resources.

Quantifying water productivity and nitrogen uptake of maize under water and nitrogen stress in arid Northwest China

Water and nitrogen (N) are critical determinants of crop water productivity (WP) and N uptake (Nuptake), and are also key factors in crop modelling. Through a two-year field experiment with three irrigation levels (full irrigation (W1), moderate water stress (W0.75), and severe water stress (W0.5)), three N application rates (150, 75, and 0 kg N ha−1, i.e., N150, N75, and N0) and three replications for each treatment in Northwest China, we quantified the effects of water and N stress on the growth, yield, and water and N use efficiency (WP and NUE) of hybrid seed maize (Zea mays L. cv. Tianruifeng). Furthermore, nonlinear dynamic water productivity (WP) models and water (ET)-based Nuptake models were developed. The results showed that water stress had a larger impact than N stress on the growth and yield of maize, with water stress reducing yield (Y), final aboveground biomass (B), and N uptake by 36.5%, 15.4%, and 25.7% on average, respectively, and N stress decreasing them by 18.7%, 12.3%, and 13.6%, respectively. Biomass-based water productivity (WPB-ET) and yield-based water productivity (WPY-ET) at the end of the growth period responded differently to water stress but similarly to N stress because of a higher decrease of harvest index (HI) under water stress than under N stress. Specifically, WPY-ET decreased significantly while WPB-ET kept relatively stable as water stress increased. The variation of the measured WP during the growth period presented a single peak trend. The Logistic, Sigmoid, and Linear models showed similar high accuracy for quantifying the relationship between evapotranspiration accumulation and biomass growth. However, the derived WP values from the nonlinear dynamic models were more in line with the single peak variation of the measured WP during the growth period, with the agreement index (d) improved from 0.21 to 0.65–0.75 in comparison to the Linear model. The developed ET-based N accumulation models can quantify N uptake through evapotranspiration. The results can contribute to improving the accuracy of crop modelling under drought stress conditions, and the design of irrigation and N management in arid and semi-arid regions.

Effect of Planting Geometry on Growth, Water Productivity, and Fruit Quality of Tomatoes under Different Soil Moisture Regimes

The present study investigated the impact of planting spacing on tomato crop growth, water productivity, and fruit quality under different water regimes. Thus, a field experiment was conducted using a randomized complete block design in a factorial arrangement of treatments. The tomato plants were grown at three planting spacing patterns: 30 cm row-to-row planting spacing, 60 cm row-to-row planting spacing, and 90 cm row-to-row planting spacing, which were marked as (G1), (G2), and (G3), respectively. For each planting spacing pattern, irrigation regimes, namely (I1), (I2), and (I3), were established by setting the soil moisture content to 50%, 100%, and 150% of the reference evapotranspiration. The I3 × G2 combination resulted in the maximum values of plant height (68.2 cm), stem diameter (12.1 mm), and yield (41,269.9 kg/hm2), providing the highest contents of protein (1.93 mg/kg), fat (0.81%), fiber (3.94%), and lycopene (4.00 mg/kg) of the fresh fruit. Conversely, the I1 × G1 led to the minimum values of plant height (37.3 cm), stem diameter (5.65 mm), and yield (7814.7 kg/hm2), providing the lowest contents of protein (1.15 mg/kg), fat (0.50%), fiber (2.39%), and lycopene (2.15 mg/kg) of the fresh fruit. The I1 × G1 had the highest water productivity (25.06 kg/m3) value, while the lowest WP (10.23 kg/m3) value was achieved by I3 × G3. While the I1 × G3 treatment minimized the uniformity coefficient and distribution uniformity, the I3 × G3 treatment maximized their values, indicating more uniform water distribution. Our findings indicate that the I3 × G2 combination can increase tomato productivity, growth, and fruit quality. However, the I1 × G1 performed better in terms of water productivity. The results of this study can positively contribute to improving tomato production systems’ sustainability, productivity, and quality under the increasing problem of climate change.

Farklı Sulama Aralıkları ve Düzeylerinin Salçalık Domatesin Verim ve Kalite Bileşenlerine Etkileri ve Ekonomik Analizi

This study was carried out to determine the effects of different irrigation intervals (II) and irrigation levels (IL) on yield, quality and net income values of processing tomato cultivation in a sub-humid climatic zone in 2019. A split-plot randomized complete block design with three replicates was used for the field experiments. The II4-days (A) and 8-days (B) were determined as main-plot factor and different IL were established according to 100% (T1), 80% (T2) and 60% (T3) of the cumulative evaporation occurring in the Class A pan were determined as the sub-plot factor. Seasonal crop evapotranspiration (ET) values varied between 419 and 527 mm. The effects of different irrigation strategies on fruit yield, average fruit weight, brix and water productivity values of processing tomato were significant at the p<0.01 level. The greatest fruit yield was obtained in AT1 treatment with 111.65 t ha-1. The highest water and irrigation water productivity values were obtained from AT2 as 22.4 kg m-3 and 31.4 kg m-3 and the lowest values from BT3 treatment as 16.1 kg m-3 and 26.0 kg m-3 respectively. The yield response factor (ky) was determined as 1.7 for the growing season. The net income values of different treatments ranged from 213.49 to 5557.54 $ ha-1 and the net income increased with the augmentation inthe irrigation water applied. Based on the study results, AT1 treatment was recommended to obtain maximum fruit yield and net income. However, in locations with limited water resources, AT2 treatment which provides a reasonable balance between quality components and water requirements can also be evaluated.

Crop Water Productivity and Crop Coefficients of Lentil (Lens Culinaris M.) Under Different Irrigation Regimes

This study was conducted for two consecutive winter seasons (2014/15 and 2015/16) at Hudeiba Research Station Farm to determine the effects of deficit irrigation imposed at different developmental stages and throughout the growing season on water use and water productivity of lentil (L. culinaris M.) and to derive the crop coefficient. Lentil Aribo cultivar wasgrown under six irrigation treatments in which one-irrigation was skipped at some of the growth stages, i.e. vegetative (W3), flowering (W4), pod setting (W5) and ripening stage (W6) and irrigation without skipping with intervalsof 10 days (full irrigation) (W1) and irrigation every 15 days (W2) (moderate water stress throughout the growing season). The experimental and/or high cost of irrigation water conditions, if only one irrigation is to be saved, the vegetative and ripening stages could be a safe option. design was randomized complete block design with three replications. Theaverage estimated values of crop coefficients during the initial, mid -season and late -season stages were 0.28, 1.06 and 0.48, respectively. The results revealed that the highest grain yield was recorded in full irrigation (1003 kgha-1) and significantly (p < 0.001) decreased by 13, 28 and 31% when deficit irrigation was applied throughout the growing season, at flowering and at pod setting stages, respectively. The highest and lowest values of crop waterproductivity resulted from deficit irrigation imposed at vegetative stage and at flowering stages, respectively. The most sensitive stages of lentil to water deficit were the flowering and pod setting. Therefore, under water shortage

Potential productivity of Arundo donax in two contrasting environments from medium-term experiments

ABSTRACT Marginal land exploitation devoted to versatile crops, such as giant reed, is related to the degree of land marginality. Two experiments were conducted in two sites of Sardinia (Italy) to investigate the effects of management on dry matter yield and water productivity (WP). Experiment 1 compared four crop evapotranspiration restoring treatments (100%, 75%, 50%, 25%, and a rainfed control) over 5 years. Experiment 2 lasted 7 years and investigated zero-input supply on crop response. Experiment 1, notwithstanding well-watered conditions (Irr100), showed a higher value of biomass production during the last year monitored, but yielding only 13.5 Mg DM ha−1 and with no significant difference from Irr75. Moreover, being equal the average dry matter yield, in the Irr100, we would save 3630 m3 of irrigation water by achieving the same WP recorded in the Irr25 (25% ETc restoring). Experiment 2, being equal rainfall amount, raised WP values that picked 8.2 kg m−3 during 2018. Results indicate that in less favourable soils as the Experiment 1, well-watered conditions do not ensure better crop growth and productivity, whereas in deep soils (Experiment 2) promising productive results, as well as ecosystem services, could be obtained without any input supply.