Irrigation Water Use Efficiency Research Articles

Drought resistance, quality characteristics and water‐yield relationships of some wheat (Triticum aestivum L.) lines and varieties

AbstractThe aim of this study was to determine the drought tolerance of four different genotypes, including two wheat varieties (Ceyhan 99 and Sagittario) and two wheat lines (Zdeb101 and Zdeb102), and create irrigation schedules. This study was performed with treatments applied at three irrigation levels (S100: treatment where the entire water need of the plant was met, S50: 50% of the water provided in the S100 treatment, S0: Rainfed), with four genotypes and four replications in a split‐plot design in Kahramanmaras East Mediterranean Transitional Zone Agricultural Research Institute in 2019 and 2020. The Ceyhan 99 and Sagittario varieties, which are widely cultivated in the region and the Zeb101 and Zdeb102 lines that are candidates for varieties were used in the study. In the study, 217.1 and 213.77 mm of water was given to S100, 108.54 and 106.88 mm of water was given to S50, and no irrigation was provided to S0 in 2019 and 2020, respectively. The effects of different irrigation levels on yield, water use efficiency (WUE), irrigation water use efficiency (IWUE), protein content and wet gluten content were investigated. At the end of this study, seasonal evapotranspiration (ET), irrigation water and yield decreased from S100 to S0. WUE, IWUE and yield response factor (Ky) values showed different trends in both years. There was no significant difference in yield between the varieties. However, in the stress susceptibility index (SSI) analyses of the genotypes, it was found that the most drought‐tolerant genotypes were Zdeb102 (0.50) and Ceyhan 99 (0.54). The highest protein content and wet gluten content were found as 11.38% and 22.24% in the Sagittario variety, respectively. It is recommended that Zdeb102 and Ceyhan 99 be cultivated in regions such as Kahramanmaras which have semi‐arid climate characteristics in the Mediterranean.

Assessing the effect of deficit drip irrigation regimes on crop performance of eggplant

Irrigation of eggplants tremendously increases their yields amidst climate change. However, little is known about the deficit irrigation level for optimum growth of eggplant crops. This study investigated the effect of deficit drip irrigation on performance of eggplants to guide improvement in irrigation water use efficiency (IWUE). The study was conducted on sandy clay loam soil for two growing seasons using a randomized complete block design (RCBD) field experimental set up. The considered treatments were: percentages of Field Capacity (FC) as T1: 25 % FC; T2: 50 % FC; T3: 75 % FC; T4: 100 % FC; with a control being no irrigation (T0: 0 % FC), and all were performed in triplicates. Irrigation scheduling was based on the readings of the ML3 Thetaprobe sensor from which the soil moisture deficit was calculated and adjusted to percentages corresponding to the different treatments, under supplementary irrigation. All Treatments were subjected to the same agronomic treatments. Plant growth parameters, yield, IWUE, and fruit quality parameters were determined. Analysis of Variance was performed with R Studio software at 5 % significance level, and Tukey multiple comparison test was used for separating the means. Results showed that plant growth, yield, IWUE, and crop quality parameters significantly differed (p < 0.05) across the deficit levels. The highest mean yield, and IWUE of 39.1 ton/ha and 18.1 kg/m3 respectively were obtained in T3. The lowest mean yield was 13.5 ton/ha in T0, while the lowest mean IWUE was 6.2 kg/m3 in T1. The results imply that T3 is a limit of crop water application beyond which yield and IWUE of eggplants cease to increase and thus, start reducing. This study therefore, concludes that irrigating eggplants at 75 % FC maximizes yield and water saving in sandy clay loam soil.

Impact of Aerated Drip Irrigation and Nitrogen Application on Soil Properties, Soil Bacterial Communities and Agronomic Traits of Cucumber in a Greenhouse System.

Root hypoxia stress and soil nutrient turnover have been related to reduced crop productivity. Aerated drip irrigation (ADI) can effectively enhance crop productivity and yield. However, the response of the soil bacterial community to different irrigation water dissolved oxygen (DO) concentrations remains elusive due to the extreme sensitivity of microorganisms to environmental variations. We investigated the effects of aerated irrigation with different concentrations of DO on soil properties and agronomic performance of cucumber, as well as the contribution of the bacterial community. We performed experiments on cucumber cultivation in Shouguang, China, including different irrigation methods (ADI: O2-10 and O3-20 mg L-1, non-aerated groundwater: O1-5 mg L-1) and nitrogen (N) application rates: 240 and 360 kg N ha-1. ADI (particularly O2) significantly improved soil properties, root growth, cucumber yields, and irrigation water use efficiency (IWUE), and appropriate DO concentrations reduced N fertilizer application and increased crop yields. Furthermore, these changes were associated with bacterial community diversity, aerobic bacteria abundance, and consolidated bacterial population stability within the network module. Environmental factors such as soil respiration rate (Rs), DO, and NO3--N have significant effects on bacterial communities. The FAPROTAX results demonstrated enhanced nitrification (Nitrospira) and aerobic nitrite oxidation by soil bacteria under ADI, promoting the accumulation of effective soil N and improved soil fertility and crop yield. Appropriate DO concentration is conducive to the involvement of soil bacterial communities in regulating soil properties and cucumber growth performance, which are vital for the sustainable development of facility agriculture.

Comprehensive Regulation of Water–Nitrogen Coupling in Hybrid Seed Maize in the Hexi Oasis Irrigation Area Based on the Synergy of Multiple Indicators

Water scarcity and the excessive application of nitrogen fertilizer are key factors limiting the sustainable development of the hybrid seed maize industry in the oasis agricultural areas of the Hexi Corridor in China. To determine the optimal water–nitrogen management regime of hybrid seed maize, we established a field experiment in 2020–2021 with three irrigation quotas (W1, W2, and W3 were 60, 80, and 100% of the local conventional irrigation quota, respectively) and four nitrogen application levels (N0, N1, N2, and N3 were 0, 190, 285, 380 kg·hm−2). We analysed the influence of different water–nitrogen combinations on indices of seed vigour, yield, water use efficiency (WUE), irrigation water use efficiency (IUE), the partial productivity of nitrogen fertilizer (NFP), and the nitrogen fertilizer agronomic use efficiency (NFA) of hybrid seed maize. A comprehensive growth evaluation system for hybrid seed maize was established based on the AHP, entropy weight, and TOPSIS methods, and a coupled water–nitrogen response model for hybrid seed maize was established with the objectives of obtaining high-yield, efficient, and high-seed vigour. The results showed that the yield of hybrid seed maize, NFP, and NFA gradually increased with the increase in the irrigation amount, while IUE continuously decreased; the yield of hybrid seed maize, WUE, and NFA increased and then decreased, while NFP continuously decreased with an increase in the amount of nitrogen application. Further, treatment N2W3 had higher water and nitrogen use efficiency and the highest yield and seed viability with a yield of 9209.11 kg·hm−2 and germination percentage, germination index, and vigour index of 97.22, 58.91, and 1.55%, respectively. The model of the integrated growth response of hybrid seed maize to water–nitrogen showed that the combined benefits of the hybrid seed maize yield, WUE, and seed viability could be maximised in conjunction with the irrigation rate ranging from 3558.90 to 3971.64 m3·hm−2 and the fertiliser application rate of 262.20 to 320.53 kg·hm−2. This study can provide scientific guidance and act as a decision-making reference for the productive, efficient, and sustainable development of hybrid seed maize in the oasis agricultural area of the Hexi Corridor.

Assessment of Soil Water Dynamics and Yield Response of Broccoli Under Subsurface Drip Irrigation in the Semi-Arid Region of India

ABSTRACT A field experiment was conducted to investigate the optimum lateral spacing and irrigation frequency of a subsurface drip irrigation system for broccoli crop grown in the semi-arid region of Haryana (India). The effects on soil water dynamics, growth parameters (i.e. plant height, leaf length, no. of leaves/plant, curd weight and curd diameter), irrigation water use efficiency (IWUE), fertilize use efficiency (FUE) and yield response of broccoli were assessed under two lateral spacings (45 cm and 60 cm) and four irrigation frequencies (daily, and after one, two & three days) in the years of 2019–20 and 2020–21. The results show that soil moisture content was higher near the dripper, and it decreased with increasing radial distance from the drippers. Further, the moisture content was high at 45 cm lateral spacing as compared to 60 cm lateral spacing. The effects of selected treatments on growth and yield parameters were found significant and maximum broccoli yield (147. 41 q ha−1) was found at 45 cm lateral spacing with alternate days of irrigation. The highest IWUE and FUE of 9.93 kg/m3 and 30.68 kg/kg, respectively, were also found at alternate days irrigation with 45 cm lateral spacing. It may be concluded from the present study that alternate days irrigation with 45 cm lateral spacing is the best choice to obtain the maximum yield of broccoli grown in winter season in the semi-arid region of India.

Micro-nano oxygenated irrigation improves the yield and quality of greenhouse cucumbers under-film drip irrigation

To study the influence mechanism of micro-nano oxygenated irrigation (MNOI) on greenhouse fruit cucumber in arid and semi-arid cold regions, the yield and quality of greenhouse fruit cucumber were evaluated and verified based on 2 years of observation data. Taking fruit cucumber in Ningxia solar greenhouse as the research object, three dissolved oxygen (DO) levels of MNOI (DO; 6, 7.5, and 9 mg L−1, O1, O2, and O3, respectively) and non-oxygenated irrigation (CK, 4 mg L−1) were set up as the control treatment. Through comparative design, the influence mechanism of different levels of aerobic irrigation on the yield and quality of greenhouse fruit cucumber was studied. The main indicators of fruit cucumber yield and quality increased with dissolved oxygen in irrigation water from 4 to 9 mg L−1. In spring–summer (autumn–winter), compared with CK, the leaf area index (LAI) and net photosynthetic rate (A) increased by 28.83% (28.77%) and 44.90% (35.00%), respectively, and Vitamin C, soluble protein, soluble sugar, soluble solids and total acid content increased by 100.00% (51.88%), 37.78% (61.11%), 34.17% (54.17%), 37.07% (78.72%) and 26.92% (30.67%) respectively, while nitrate content decreased by 44.88% (51.15%), and dry matter accumulation (DMA), soil respiration rate (SRR), microbial carbon (MC), and microbial nitrogen (MN) increased by 49.81% (127.25%), 55.22% (110.34%), 117.50% (90.91%) and 70.37% (74.42%) respectively, and yield, irrigation water use efficiency (IWUE) and soil oxygen content (SO) increased by 22.47% (28.04%), 22.39% (28.05%) and 33.21% (35.33%) respectively. A model of DO in irrigation water and SO was established and the applicability of the model was verified with an average relative error of 2% (less than 5%). MNOI increased SO and soil enzyme activity, enriched soil microorganisms, improved soil microenvironment, promoted water nutrient uptake and growth of root system, increased chlorophyll, photosynthesis and DMA, which improved fruit cucumber yield and quality, and the better DO concentration in irrigation water is 9 mg L−1. The research results provide theoretical support for regulating soil water, fertilizer and air environment, and at the same time, provide feasible ways to improve the quality and efficiency of crops in arid and semi-arid cold regions.

Climate change impacts assessment and developing adaptation strategies for rainfed foxtail millet in northern Shanxi, China

Climate change is considered to be a serious threat to crop production around the globe. In the northern Shanxi Province of China (SXN), foxtail millet (or millet) is the main crop and generally grows under rainfed conditions. Existing literature has confirmed the millet yield reductions due to climate change in the past. However, little is known about the impacts of future climate change on millet production in the SXN. The main objectives of this study were to investigate the future climate change impacts under two emission scenarios (SSP245 and SSP585) and the potentials of shifting sowing date combined with supplemental irrigation as an adaptation strategy to climate change for millet production in the SXN using the Decision Support System for Agrotechnology Transfer (DSSAT). Two supplemental irrigation strategies were tested: one presowing irrigation only (PSI), and two supplementary irrigations (PSGI) adopting one presowing irrigation and one irrigation during the growing season. We found that the air temperature, solar radiation and precipitation during the millet growing season in the future (2021–2060) are higher than those in the baseline (1981–2020). The rainfed millet yield will decrease by 8.6 % (SSP245) and 16.5 % (SSP585) in the future without an adaptation strategy, compared to the baseline yield (2.43 t ha−1) in 1981–2020 under the conventional sowing date. The reduction in rainfed millet yield caused by climate change cannot be reversed by shifting sowing date, but can be slightly mitigated by a suitable advancement of the sowing date. Adopting supplemental irrigation in the future can achieve higher millet yield than the baseline yield, especially PSGI. Compared to PSI, PSGI consumes more irrigation water but has higher irrigation water use efficiency (IWUE). There is a synergy between shifting sowing date and supplemental irrigation in coping with climate change, and a later sowing date than the conventional one (30 April) is recommended under supplemental irrigation in the future. In 2021–2060, the best adaptation strategy to climate change for maximizing grain yield, IWUE and economic benefit in the millet production of the SXN is that supplementary irrigation is applied before sowing and on 20 July–30 July combined with the sowing dates of 10 May–20 May.

Numerical simulation of clogging of two types of emitters with similar properties

AbstractThe benefits of drip irrigation are numerous and include water savings, control of fertilizer applications, and improved water and energy use efficiency of irrigation. In these systems, the emitter is the most vulnerable component to clogging, which in critical states can cause a reduction in performance and shorten the life of the distribution system. It can also have several impacts on water, its economy, and its wastage. In the absence of adequate filtration and when the flow is through the narrow labyrinth channel of the emitter, clogging can be created by continuous deposition of solid particles, organic matter, dissolved salts, chemical precipitates, bacteria, and other impurities. It is obvious that it is impossible to physically visualize the hydraulic behavior of the flowing water in the labyrinths. However, due to the increasing performance of computational tools and simulation software, it is possible to simulate this flow through Computational Fluid Dynamics (CFD), which has become one of the main techniques for describing the flow and deposition of the solid phase inside the emitter. This study aims to numerically simulate the behavior and the flow of the fluid inside two emitters, widely used in the industry, with different types but approximately identical flow rates. The fluid takes in its flow an inert solid suspension of fixed concentration. One of the emitters is compensating‐pressure, and the other is non‐compensating‐pressure; the numerical simulation model used is the RNG κ‐ε two‐phase model. The results showed that the regions affected by clogging are mainly the corners of the labyrinth channel and the recirculation vortex zones. The trajectory field plot reveals that as the clogging increases, the serpentine fluid threads become thinner.

Soil Moisture, Nutrients, Root Distribution, and Crop Combination Benefits at Different Water and Fertilizer Levels during the Crop Replacement Period in an Apple Intercropping System

Uneven soil moisture and nutrient distribution before and after intercropping limits apple cropping system productivity in the western Shanxi–Loess Plateau area. To address this issue, a field trial was conducted between 2020 and 2021 to study the effects of different water and fertilizer management practices on soil moisture, nutrients, and root distribution, as well as the overall effectiveness of the apple–maize and apple–soybean intercropping systems during crop replacement. The experiment involved two irrigation methods: drip (D) and flood (M) irrigation. Three irrigation levels included rain-fed without irrigation (W0), and 50% (W1) and 80% (W2) of field capacity (Fc). Three fertilizer treatments included no additional fertilizer application (F0), 375 kg∙hm−2 (F1), and 750 kg∙hm−2 (F2), in addition to a control (CK) without irrigation or fertilization. The soil water content (SWC) decreased after the crop replacement. Additionally, nitrate nitrogen (NN), ammonium nitrogen (AN), and organic matter (OM) content levels in all treatments increased, whereas total phosphorus (TP) content decreased. The soil layer with crop roots moved downward after crop replacement, and partial fertilizer productivity (PFP), irrigation water use efficiency (IWUE), and water use efficiency (WUE) were decreased under both irrigation treatments. Principal component analysis showed that the W2F2 treatment had the highest benefit from crop combination across both irrigation treatments during the crop replacement period. According to our results, to optimize the benefits of apple-crop intercropping, drip irrigation with complete water supply and flood irrigation with incomplete water supply are recommended during crop replacement. In addition, an upper irrigation limit of 80% Fc with 750 kg∙hm−2 fertilization is recommended for optimal water and fertilizer regulation.

Green waste-derived compost (GWC) alleviates drought stress and promotes sugar beet productivity and biofortification

ABSTRACT Green waste-derived compost (GWC) is a valuable soil amendment for improving soil organic matter and decreasing waste products and potential pollutants. The study was carried out to evaluate the effect of GWC application on the yield and quality of sugar beet under deficit irrigation conditions using different irrigation systems. A field experiment was conducted using the commercial sugar beet variety Gazelle in sandy soil. Two doses (0 and 14 t ha−1) of GWC were applied to the soil. Three water deficiency levels (60, 80 and 100% of the soil field capacity) under either drip and sprinkler irrigation systems were applied. The application of 14 ton ha−1 of GWC resulted in the highest root and recoverable sugar yields, especially under the well-irrigated conditions under drip irrigation. Sugar beet root biofortification and juice quality were also significantly improved under drip irrigation in response to the application of 14 ton ha−1 of GWC by increasing sucrose content, quality index (Qz)% and recoverable sugar (RS)%. The application of GWC under drip irrigation enhanced water use efficiency for root (WUERY) and recoverable sugar yields (WUERSY), in particular under drip irrigation and water deficit conditions (60% of the soil field capacity). The soil physicochemical properties were significantly improved in response to the application of GWC. GWC application promoted the yield and biofortification of sugar beet by improving the soil physiochemical properties, and nutrient mobilization and uptake. The application of GWC is essential for sustainable sugar beet production and efficient irrigation water use in sandy soils.

Effect of using reclaimed water via furrow and subsurface drip systems under alternate partial root-zone irrigation mechanism on crops growth and soil properties

The growing population in the face of water scarcity inevitably necessitates the quest for alternative sources of irrigation water, which integrates them with irrigation strategies for improved agricultural productivity to meet the Sustainable Development Goals. A three-year field experiment was conducted in 2017, 2018, and 2019 to investigate the effect of water quality (reclaimed water (RW) and clean water (CW)), irrigation techniques (subsurface drip irrigation (SDI) and furrow irrigation (FUI)), irrigation methods (full irrigation (FI) and alternate partial root-zone irrigation (APRI) (70% ETc)), and their interactions on the fresh fruit yield (FY), irrigation water use efficiency (IWUE), and nitrogen use efficiency (NUE) of tomatoes. Further, electrical conductivity (EC), pH, and organic matter (OM) of soil were evaluated. The experiments were undertaken over three growing spring seasons in a greenhouse at the Chinese Academy of Agricultural Sciences in Henan Province, China. Throughout the three years of this study, the yield, the IWUE, and the NUE values of all treatments under RW were higher than those corresponding values under CW. The trend was the same under SDI as it was under FUI. Statistical analyses revealed that there was no significant effect (P > 0.05) of water quality, irrigation technique, and irrigation methods on the soil EC, pH, and OM over the three years. In addition, the interaction between the different experimental factors over the three years of the study was not significant. In conclusion, the application of RW under SDI can result in saving CW and increasing productivity without any negative effect on the investigated soil properties. Furthermore, when RW-SDI is used in conjunction with APRI, it can result in increasing IWUE.

Effect of irrigation termination times on cotton cultivars with contrasting maturities

AbstractOptimizing irrigation termination time can save water and preserve lint yield and fiber quality in cotton. Although there is currently an irrigation termination recommendation in Georgia, the ideal time for termination could be influenced by cultivar differences in maturity. The hypotheses of this study were that differential irrigation termination times will affect lint yield, fiber quality, and incidence of hardlock and boll rot, and responses will be dependent on cultivar differences in maturity. In 2021 and 2022, a study was conducted in Camilla, GA, using two cotton cultivars with contrasting maturities under four irrigation termination treatments. Irrigation was terminated at cutout, first open boll, 2 weeks after first open boll, and 4 weeks after first open boll. Measurements included plant growth, cutout date, lint yield, irrigation water use efficiency (IWUE), fiber quality, and incidence of boll diseases. Gas exchange measurements and percent open boll estimates at each irrigation termination time were also conducted. Terminating irrigation at cutout did not significantly affect yield in either year; however, IWUE increased 12.6% relative to current recommendations and 13.2% relative to the latest termination time in the 2022 season. Cultivars differed significantly in cutout date, agronomic maturity, gas exchange rates, yield, hardlock/boll rot incidence, and fiber quality. However, there was no interaction between cultivar and irrigation termination time for any parameter. We conclude that irrigation can be terminated at cutout to maximize IWUE, for early and late‐maturing cultivars, without limiting yield or fiber quality, assuming a water‐replete soil profile at termination.

Management Soil Zones, Irrigation, and Fertigation Effects on Yield and Oil Content of Coriandrum sativum L. Using Precision Agriculture with Fuzzy k-Means Clustering

Precision agriculture (PA), management zone (MZ) strategies at the field level, soil analyses, deficit irrigation (DI), and fertilizer Variable Rate Application (VRA) are management strategies that help farmers improve crop production, fertilizer use efficiency, and irrigation water use efficiency (IWUE). In order to further investigate these management strategies, the effects of four soil MZ treatments, which were delineated using PA with fuzzy k-means clustering, two irrigation levels [IR1:FI = full drip irrigation (&gt;90% of θfc), IR2:VDI = variable deficit drip irrigation (60–75% of θfc)], and four VRA fertilizations were studied on coriander yield and essential oil content in a two-year research project in Greece. A daily soil-water-crop-atmosphere (SWCA) balance model and a daily depletion model were developed using sensor measurements (climatic parameter sensors as well as soil moisture sensors). Unbalanced one-way ANOVA (p = 0.05) statistical analysis results revealed that correct delineation of MZs by PA with fuzzy k-means clustering, if applied under deficit irrigation and VRA fertilization, leads to increased essential oil content of coriander with statistically significant differences (SSD) and lower fruit yields; however, without SSD differences among management zones, when appropriate VRA fertilization is applied to leverage soil nutrient levels through the different fuzzy clustered MZs for farming sustainability. Moreover, VDI compared to full irrigation in different MZs yields 22.85% to 29.44% in water savings, thus raising IWUE (up to 64.112 kg m−3), nitrogen efficiency (up to 5.623), and N-P-K fertilizer productivity (up to 5.329).

Interactive effects of biochar and chemical fertilizer on water and nitrogen dynamics, soil properties and maize yield under different irrigation methods.

Long-term application of nitrogen (N) fertilizer adversely degrades soil and decreases crop yield. Biochar amendment with N fertilizer not only can increase yield but also can improve the soil. A 3-year field experiment was conducted to determine the effect of biochar doses with N fertilizer on maize yield and soil N and water dynamics under border irrigation (BI) and drip irrigation (DI) methods. Treatments were 260kg N ha-1 without biochar addition and combined with low, medium, and high doses of biochar, namely, 15.5t ha-1, 30.7t ha-1, and 45.3t ha-1 (NB0, NB1, NB2, and NB3), respectively. The biochar doses and irrigation methods significantly (p < 0.05) increased maize growth and yield characteristics, irrigation water use efficiency (IWUE), and fertilizer N use efficiency (FNUE) and enhanced the soil properties. In the BI and DI method, the NB1, NB2, and NB3 treatments increased yield by 4.96%-6.10%, 8.36%-9.85%, and 9.65%-11.41%, respectively, compared to NB0. In terms of IWUE and FNUE, the non-biochar treatment had lower IWUE and FNUE compared to biochar combined with N fertilizer treatments under both BI and DI methods. In the BI method, the IWUE in NB2 and NB3 ranged from 3.36 to 3.43kg kg-1, and in DI, it was maximum, ranging from 5.70 to 5.94kg kg-1. Similarly, these medium and high doses of biochar increased the FNUE of maize. The FNUEs in NB2 and NB3 under BI ranged from 38.72 to 38.95kg kg-1 and from 38.89 to 39.58kg kg-1, while FNUEs of these same treatments under DI ranged from 48.26 to 49.58kg kg-1 and from 48.92 to 50.28kg kg-1. The effect of biochar was more obvious in DI as compared to the BI method because soil water content (SWC) and soil N concentrations (SNCs) were higher at rhizosphere soil layers under DI. Biochar improved SWC and SNC at 0-20 cm and 20-40 cm soil layers and decreased below 60-cm soil layers. In contrast, despite biochar-controlled SWC and SNCs, still, values of these parameters were higher in deeper soil layers. In the BI method, the SNCs were higher at 60-80 cm and 80-100 cm compared to the top and middle soil layers. Depth-wise results of SNC demonstrated that the biochar's ability to store SNC was further enhanced in the DI method. Moreover, biochar increased soil organic matter (OM) and soil aggregate stability and maintained pH. The NB0 treatment increased soil OM by 11.11%-14.60%, NB2 by 14.29%-19.42%, and NB3 by 21.98%-23.78% in both irrigation methods. This increased OM resulted in improved average soil aggregates stability by 2.45%-11.71% and 4.52%-14.66% in the BI and DI method, respectively. The results of our study revealed that combined application of N fertilizer with a medium dose of biochar under the DI method would be the best management practice, which will significantly increase crop yield, improve SWC, enrich SNC and OM, improve soil structure, and maintain pH.

Enhancing water use efficiency in precision irrigation: data-driven approaches for addressing data gaps in time series

Real-time soil matric potential measurements for determining potato production's water availability are currently used in precision irrigation. It is well known that managing irrigation based on soil matric potential (SMP) helps increase water use efficiency and reduce crop environmental impact. Yet, SMP monitoring presents challenges and sometimes leads to gaps in the collected data. This research sought to address these data gaps in the SMP time series. Using meteorological and field measurements, we developed a filtering and imputation algorithm by implementing three prominent predictive models in the algorithm to estimate missing values. Over 2 months, we gathered hourly SMP values from a field north of the Péribonka River in Lac-Saint-Jean, Québec, Canada. Our study evaluated various data input combinations, including only meteorological data, SMP measurements, or a mix of both. The Extreme Learning Machine (ELM) model proved the most effective among the tested models. It outperformed the k-Nearest Neighbors (kNN) model and the Evolutionary Optimized Inverse Distance Method (gaIDW). The ELM model, with five inputs comprising SMP measurements, achieved a correlation coefficient of 0.992, a root-mean-square error of 0.164 cm, a mean absolute error of 0.122 cm, and a Nash-Sutcliffe efficiency of 0.983. The ELM model requires at least five inputs to achieve the best results in the study context. These can be meteorological inputs like relative humidity, dew temperature, land inputs, or a combination of both. The results were within 5% of the best-performing input combination we identified earlier. To mitigate the computational demands of these models, a quicker baseline model can be used for initial input filtering. With this method, we expect the output from simpler models such as gaIDW and kNN to vary by no more than 20%. Nevertheless, this discrepancy can be efficiently managed by leveraging more sophisticated models.

Minimizing seepage in irrigation canals in land reclamation systems via an innovative technology

The escalating demand for water and the impact of climate change are posing significant challenges to global water scarcity and agricultural policies. The aim of this research is to investigate the factors influencing water losses in irrigation systems and provide recommendations to minimize such losses. The research methodology includes conducting studies to identify the factors causing water losses through evaporation and seepage from irrigation canals in the Kazakh part of the Ile River basin. The research results are theoretically substantiated, and a series of field studies are carried out at the inter-farm canal experimental site in Almaty province. Based on the factors affecting evaporation and seepage losses in irrigation canals, a new design of irrigation canal made from geocomposite material has been developed and introduced. This design helps to prevent water losses in inter-farm and on-farm canals of reclamation systems. The geocomposite polymer troughs have improved the technical level of irrigation systems and have enabled additional irrigation areas by increasing the efficiency of irrigation water use in land reclamation systems of Kazakhstan, thereby enhancing the efficiency factor of the irrigation network. Water seepage losses are influenced by several factors, including soil type, canal length, working flow, canal operation mode, canal condition, operation season, and wind impact. Under uniform canal operation mode, water losses are relatively small. However, intermittent modes and incomplete filling of the canal result in increased costs. The research findings indicate that for soils with a flow velocity between 0.10 and 0.30 M/s, water losses due to leakage and evaporation in constant-impact and intermittent-impact channels increase linearly. In intermittent-impact channels, irrigation water losses range from 33.7 to 40.1%. The introduction of geocomposite polymer troughs has the potential to enhance the technical level of irrigation systems by improving the efficiency of the irrigation network and enabling the addition of more irrigation plots. This research aims to reduce water losses in the irrigation canals of reclamation systems, optimize the management of water distribution in irrigation systems, enhance equipment measures, and introduce digital irrigation water metering technologies. Future studies propose the application of digital technologies to enhance irrigation water design and accounting as part of measures to minimize water losses in irrigation canals.

Effects of Water and Nitrogen Coupling on Yield, Quality, Water and Nitrogen Use Efficiencies of Greenhouse Muskmelon

The proficient supply of water and nitrogen is a key factor in facility agriculture. In order to pursue high yields, most farmers blindly irrigate and fertilize, leading to yield reduction, quality decline, soil salinization, and fertility destruction. A successive two-year greenhouse experiment was carried out on fruit quality, yield, irrigation water use efficiency (IWUE), and nitrogen use efficiency (NUE) of greenhouse muskmelon (Cucumis melo L.) under drip fertigation, which can provide a scientific basis for local muskmelon intensive production in Southeast China. The experiments were conducted in 2020 and 2021, with three irrigation levels 80% (W1), 100% (W2), and 120% (W3) of ETc and three N levels 60 (N1), 95 (N2), and 130 (N3) kg N ha−1. The amount of drip irrigation water was determined every 5 days based on crop evapotranspiration (ETc). The seasonal irrigation amount ranged from 209.77 mm to 298.86 mm in 2020 and from 201.22 mm to 286.04 mm in 2021. The highest muskmelon yield was obtained in the treatment of W3N3 with an average of 27.38 t ha−1 in 2020 and 27.10 t ha−1 in 2021. Although the yield was improved by increasing nitrogen supply, there was no significant difference between N2 and N3 treatment in two years under the irrigation level of W2 and W3. The highest irrigation water use efficiency was observed in the W1N3 treatment in 2020 and 2021. The NUE increased with decreasing N rates at the same irrigation level. Under the same nitrogen application level, TSS and Vc under low water (W1) were higher than that under medium water (W2) and high water (W3) treatment. The highest content of nitrate in low water and high nitrogen (W1N3) treatment was 55.41 µg/g in 2020 and 52.50 µg/g in 2021, respectively. The yield and quality of muskmelon are often incompatible, for instance, W2N2 treatment can obtain a higher yield, but W1N2 treatment maximizes Vc, TSS of muskmelon quality. Our findings suggest that the irrigation level of 1.0 ETc, nitrogen level of 95 N ha−1, and 3500 kg·ha−1 of decomposed organic fertilizer was recommended as the best combination, which can improve the yield, quality, IWUE, NUE of muskmelon under drip fertigation with soil mulching in the experimental site.

DRIP IRRIGATION REGIMES AND EFFICIENCY OF WATER USE BY SUNFLOWER HYBRIDS

The article presents the results of experimental research on the effect of drip irrigation system designs on the formation of irrigation regimes, productivity, and efficiency of water use by sunflower hybrids. In addition, the main components of evapotranspiration were taken into account, and coefficients of water consumption (WCC), irrigation efficiency (IE), and irrigation water use efficiency (WUE) were chosen as criteria for the efficiency of drip irrigation. Short-term field research was carried out during 2020-2022 on the lands of the Brylivske experimental field of the Institute of Water Problems and Reclamation of the National Academy of Agricultural Sciences (Kherson region, subzone of the Dry Steppe). Analytical and mathematical as well as statistical methods were used to process experimental data. The scheme of the three-factor field experiment provided various options for laying irrigation pipelines of drip irrigation systems (in the horizontal and vertical planes), as well as the implementation of a pulsed water supply mode (standard). The version with a natural moisture supply (without irrigation) was the control. The results of experimental research proved that the method of laying drip irrigation pipelines had a direct effect on the parameters of the formation of drip irrigation regimes and the productivity of sunflower hybrids in the conditions of the Dry Steppe. The mechanism of evapotranspiration formation of sunflower crops in irrigated and non-irrigated conditions has been determined. It was statistically proven that the application of subsoil drip irrigation with the laying of irrigation pipelines at a depth of 0.3 m and a distance between them of 1.0 m is the most appropriate for growing sunflower hybrids. This is explained by biological features, namely drought resistance of this crop. Thus, in field experiments, the variant with in-soil laying of drip irrigation pipelines provided almost identical yield (4.01-4.09 t/ha) when having lower crop water consumption coefficients (1088.7-1125.7 m3/t) and higher efficiency of irrigation water use – 2.27-2.41 kg of grain per 1 m3 of irrigation water.

Water and nitrogen management scheme of melon based on yield−quality−efficiency matching perspective under CO2 enrichment

Rising CO2 concentration in the atmosphere may modulate the response of plants to water and nitrogen, and the existing research is not sufficient to support the fine management of water and nitrogen under CO2 rise. To determine the optimal water and nitrogen strategy for melon production under CO2 enrichment in the future, we conducted an experiment with 12 treatments over three growing seasons. The effects of water nitrogen coupling on the yield, quality, and water−nitrogen use efficiency of oriental melon (Cucumis melo L. Qianyu No. 6) under CO2 enrichment were investigated and evaluated comprehensively. The treatments included two CO2 concentrations, C1 (400 ppm) and C2 (800 ppm), three irrigation levels, I1 (80% evaporation (Ep)), I2 (100% Ep), and I3 (120% Ep); two nitrogen levels, N1 (S: 184.77 kg ha–1, F: 147.21 kg ha–1) and N2 (S: 369.54 kg ha–1, F: 294.42 kg ha–1). The result showed that the yield increased with increasing levels of irrigation and nitrogen, and enriched CO2 significantly increased the yield by 10.3 − 22.9%. N2 showed a significant promoting effect on the ratio of marketable fruit in the two spring seasons. Enriched CO2 significantly increased free amino acid of I1. C2 coupled with I1 significantly reduced nitrate content by 30.9%, 14.9% in 2020 F and 2021 S, respectively. The interaction of C*I was significant in irrigation water−use efficiency (IWUE) and nitrogen−use efficiency (NUE). In particular, C2 coupled with I2 increased IWUE by 40.5%, 18.7% and NUE by 43.9%, 13.9% in the two spring seasons, respectively. Ten indicators from three categories of yield, quality, and efficiency were used to establish the evaluation system of melon and were comprehensively evaluated based on Fuzzy−Borda model combined three single models. Based on the combined evaluation model, intermediate irrigation combined with higher nitrogen input was best for melon production under CO2 enrichment. This finding suggested that melon sustainable production should control irrigation and adequately increase nitrogen fertilizer to trade−off fruit, quality, and efficiency for the expected future higher CO2 concentrations.

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.