Irrigation Water Resources Research Articles

Water Resources and Their Suitability for Irrigation in Khabat District

The suitability of water resources for irrigation is one of the important topics in studies that are related to water resources. The aim of this research is the determination of the water resources and their suitability in Khabat district The main source of water resource in the study region is the water of the Great Zab River. The annual received quantity of water at the (Efraz Station) reaches up to (8.56) m3. There is also a number of (437) water wells, (2) fountains and (3) water springs that were dug for irrigation purposes. The study has reached a conclusion based on the measurements and classifications that were made to decide the suitability of water for irrigation operations by the concentration of ions (dissolved salts, magnesium, chloride, ph, and nitrate) and classifications (Todd, Wilcox, Ussl, SAR, FAO, Altoviski, Diagram, Richards) hence, declared that most of the water resources in the study region (surface and ground water) are suitable for irrigation and watering animals.

Impacts of land-use changes and landholding fragmentation on crop water demand and drought in Wadi El-Farigh, New Delta project, Egypt

Despite Egypt’s limited water resources, more lands in the western desert of the Nile Delta are currently being reclaimed to increase the agricultural area to feed its fast-growing population and provide jobs for new generations. These reclaimed lands are prone to drought since they are located in arid regions with limited water resources for irrigation. Moreover, a high rate of landholdings fragmentation was observed with the migration of large numbers of new farmers to the newly reclaimed areas. Hence, the current work uses remote sensing data to investigate the impacts of landholdings fragmentation and land-use changes on irrigation water demand and drought propagation in two selected sites in Wadi El-Farigh area, one of the newly reclaimed valleys in the western desert of Egypt. To achieve that goal, high-resolution satellite images were used to quantify the land-use changes and patterns. The Surface Energy Balance System (SEBS) was used to estimate the actual evapotranspiration (ETa) from 2010 to 2020. Standardized Precipitation Index (SPI) and Evaporative Stress Index (ESI) were used to monitor drought. Results indicated a large transformation of seasonal herbaceous crops to tree-fruit crops in the two study sites. However, landholding fragmentation caused a reduction in the total cultivated area and thus the accumulated water consumption over one study site. Although the accumulated ETa decreased following the decline in the total cultivated area, the ETa rate per hectare increased by 18.4% and 19.6% for trees and herbaceous crops, respectively, reflecting the negative impact of climate change. ESI and SPI time series confirms that the area became extremely dry, particularly after 2017. In conclusion, land use and climate change increased crop water demand, while landholding fragmentation led to cropland loss. Hence, more policies for land protection and adaptation strategies to climate change are essentially needed.

Temporal and Spatial Distribution of Food Security Production and Total Water Resources in Western Jilin: Based on Center of the Gravity Model

In recent years, the main grain-producing areas in the west of Jilin have gradually concentrated in the perennial irrigation areas and supplementary irrigation areas in the north, and the stress degree of grain irrigation water resources is gradually increasing. Therefore, this paper selects the arid and semiarid area in the west of Jilin Province as the research area and compares and analyzes the modeling process and simulation accuracy of the temporal and spatial distribution of food security production and total water resources. Based on the center of gravity model, this paper studies the temporal and spatial distribution of food security production and total water resources in Western Jilin. It can be seen that after 2018, rice and wheat show a fluctuating upward trend, and their values rise from 0.612 to 0.786 and 0.356 to 0.612, respectively; the rise of corn is small, showing an inverted “U” trend, which first increases from 0.693 in 2018 to 0.701 in 2019 and then decreases to 0.671 in 2021; By comparing the precipitation statistics in different years, the inverted “U” trend of corn irrigation water efficiency may be related to the sudden increase of precipitation. The center of gravity model is used to analyze the evolution trend of the center of gravity of grain production and water resources in Western Jilin from the national and regional levels, and the spatiotemporal coupling degree of the center of gravity of grain production and water resources is explored through the two-factor center of gravity coupling situation model.

Diversity and composition of riparian vegetation across forest and agro-ecosystem landscapes of Cabadbaran River, Agusan del Norte, Philippines

The Cabadbaran River Irrigation System (CabRIS) supports about 3,212 hectares of farmland for irrigation. Unfortunately, the local irrigation office reported an insufficient water supply for irrigation to serve the entire service area in the past cropping seasons. The water yield has been dwindling; hence, an irrigation system management plan will address the water resource crisis. As a component of the project "Cabadbaran River Irrigation System Management Plan for Irrigation Water Resources (2022-2026)", the biophysical team carried out a floristic assessment for the entire watershed. The study used the quadrat-transect sampling method to assess and characterise the structure and species composition of the riparian areas of the main Cabadbaran River, Cabadbaran City, Agusan del Norte, Philippines. Results recorded about 109 morpho-species belonging to 46 families and 88 genera from the sampling sites. Nineteen species were listed either on the Philippine Red List or the IUCN Red List of Threatened Species. The plant diversity assessment revealed that biodiversity in riparian forests in the watershed was low to very low due to the massive rampant disturbance in the area. The riparian ecosystem of the Cabadbaran River represents a fragile ecosystem that is threatened by increasing demands on the regional water supply and the conversion of lands into tree plantations and agriculture. Addressing these driving forces causing biodiversity loss will impart a significant challenge for irrigation and land managers in the region.

Contribution of Superabsorbent Polymers to Growth and Yield of African Leafy Vegetables

Superabsorbent polymers (SAPs) have been used as water-saving materials for limited irrigation water resources in arid and semi-arid areas. The purpose of this study was to optimize SAP application dosage and irrigation intervals on the growth of African leafy vegetables (ALVs) under greenhouse conditions. A factorial experiment was conducted under greenhouse conditions to determine the optimal SAP application, dosage, and irrigation intervals for the growth and production of African leafy vegetables. Two species of African leafy vegetables were studied: cowpea (Vigna unguiculata) and African nightshade (Solanum scabrum). The experiment was performed in a randomized complete block design comprising 25 treatments: a factorial combination of five superabsorbent polymer application doses (0 g, 0.5 g, 1 g, 1.5 g, and 2 g) SAP/Kg of soil substrate and five irrigation intervals (3 days, 4 days, 5 days, 6 days, and 7 days) with three replications. Statistical analysis of the results showed that the use of SAP in irrigation can significantly promote the growth and yield of African leafy vegetables. SAP, irrigation, and their interactions significantly affected ( P < 0.005 ) the plant height, stem diameter, leaf area, number of mature leaves/plant, and dry weight of leafy vegetables. Treatment with SAP showed higher growth parameters and yield of vegetables compared to the treatments. Treatment with 1 g SAP/kg of soil substrate and 5-day irrigation interval recorded the highest plant growth and yield, with 24%, 11.7%, 11.1%, and 85.9% increase in cowpea plant height, leaf area, number of mature leaves, and dry weight/plant, respectively. The treatment with 1 g SAP/kg of soil substrate and 5-day irrigation interval was observed as the best for the optimal production of African leafy vegetables under greenhouse conditions. Hence, SAP could be a good strategy for food production within arid and semi-arid lands where water resources are scarce.

Novel hybrid machine learning framework with decomposition–transformation and identification of key modes for estimating reference evapotranspiration

The accurate estimation of reference evapotranspiration (ETo) is a fundamental requirement for precision irrigation and regional water resource planning. In this regard, the application of the standard model, FAO-56 Penman–Monteith, is limited because of insufficient meteorological data. This study aims to improve the accuracy of ETo calculations in regions with scarce meteorological data. A hybrid model integrating two data preprocessing methods (variational mode decomposition (VMD) and Box–Cox transformation (BC)) into a support vector machine (SVM) model (VMD–BC–SVM) is proposed. The model estimates the daily ETo based on the meteorological data (1980–2019) of 10 stations in the Wei River Basin of China. The VMD method was employed to extract multiple intrinsic mode functions (IMFs) and eliminate non-stationarity. This is achieved by decomposing meteorological factors, which are further transformed by BC to alleviate skewness characteristics. The least absolute shrinkage and selection operator regression (LASSO) identifies the key driving modes from the transformed IMFs, which are used as the input of the SVM model. The VMD–BC–SVM estimation model framework based on decomposition–transformation–identification–estimation is proposed. The performance of each of the hybrid VMD–BC–SVM models was further compared with those of the standalone extreme learning machine (ELM) model and two empirical models (Hargreaves–Samani and Priestley–Taylor models). The results revealed that the hybrid models outperformed the single models. The VMD–BC–SVM model achieved higher accuracy compared with the other models. Specifically, the coefficient of correlation (R) and Nash–Sutcliffe efficiency coefficient (NSE) were both greater than 0.96. Furthermore, the mean absolute percentage error (MAPE) and root mean square error (RMSE) were less than 8.41% and 0.38 mm/d, respectively. In terms of the amount of information provided, the VMD–BC–SVM model is superior to empirical models in identifying high-dimensional and nonlinear information. Moreover, the estimation performance is more stable, and the level of uncertainty is lower. This study provides a novel approach for predicting ETo in regions with limited meteorological data.

Hydrogeochemical assessment of streamwater quality for its suitability for irrigation: the case of Manthong village, Kanglung (Bhutan)

Abstract Mountain streams/springs are the primary irrigation water resource in Bhutan Himalaya, besides supporting drinking and other domestic needs. Successful crop production implies an adequate supply of high-quality irrigation water, among other factors. Thus, this study was conducted to assess the suitability of spring-fed streamwater for irrigation use and evaluate hydrogeochemical processes that regulate streamwater chemistry at the Manthong village in Kanglung, Bhutan. The water samples were analyzed for temperature, pH, electrical conductivity (EC), turbidity, total dissolved solute (TDS) and major ions. Piper and Durov diagrams indicated that most samples are of the intermediate type and simple dissolution or linear mixing is the primary hydrochemical process regulating streamwater chemistry. All the measured physicochemical parameters were within the acceptable thresholds of the FAO guidelines recommended for agricultural use. Analytical results of the streamwater water quality indices, including EC, %Na, residual sodium bicarbonate (RSBC), sodium adsorption ratio (SAR), Kelley's ratio (KR) and permeability index (PI), revealed its suitability for irrigation use except for magnesium hazard (MH). The Irrigation Water Quality Index (IWQI) results confirmed that the WS-1 has no restriction as irrigation water; however, WS-2 falls under the high-restriction category. The findings of this study will serve as the baseline data and guide irrigation water management and sustainable irrigation development in the region.

Utilization of Remote Sensing and GIS techniques for Diagnosing Irrigation Water Resources: A Review

Utilization of Remote Sensing and GIS techniques for Diagnosing Irrigation Water Resources: A Review

Managing irrigation water resources with economic benefit and energy consumption: an interval linear multi-objective fractional optimization model under multiple uncertainties

At present, water shortage has increasingly become one of the key factors restricting the sustainable development of agriculture. And during the process of agricultural production, the energy consumption has also been paid more and more attention. Therefore, in order to deal with the above problems, an improved interval linear multi-objective fractional programming model (ILMOFPM) was developed, which has the characteristic is that it not only focuses on the optimal allocation of the amount of irrigation water resources, but also on improving irrigation water resources use efficiency. To demonstrate its effectiveness and applicability, ILMOFPM was applied to a case study in Jinghuiqu irrigation district, Shaanxi Province, China. Maximum economic benefit per unit of water resource and minimum energy consumption per unit of water resource were selected as the planning objectives. A series of irrigation water resources optimal allocation schemes were obtained, which could give the decision makers the desired optimal scheme according to the actual situation. Based on the results of the established model, economic benefit and energy consumption generally decreased as the representative hydrological years changed from wet to dry, and the total crop planting area also showed a decreased trend. Moreover, a lot of water resources was saved by introducing crop evapotranspiration and effective precipitation in the developed model, 57.45%, 44.17%, 39.33% of total water resources consumption were saved under different representative hydrological years, respectively.

FEASIBILITY OF HORIZONTAL SUBSURFACE FLOW AS AN ALTERNATIVE TECHNIQUE FOR WASTEWATER TREATMENT IN DEVELOPING COUNTRIES

Ramadi is one of the Iraqi cities which doesn't have a WWTP. The generated domestic wastewaters are treated by the individual septic tanks. Hence, most domestic wastewater is percolating into the subsurface water and groundwater causing their pollution. The tragedian water shortage scenarios predicted by other studies have motivated the looking for new water resources. The reuse of treated wastewater is one of these alternatives. Therefore, this study tries to investigate the feasibility of using such a cheap and easy controlled technique as a horizontal subsurface flow (HSF) for treating wastewater. A lab-scale reactor has been built up from acrylic, one half of its height was filled with soil that has been collected from a selected region. The reactor was charged with wastewater using batch feeding (30 L each run) and the study lasted for 3 months with an average of one run weekly including the acclimatization period. Results revealed the fairly contaminants’ removal, where the average removal efficiency of COD, BOD5, and TSS were 76%, 73%, and 90%, respectively. In conclusion, the HSF is a reasonable, low cost, less complicated treatment technology that could be adopted as an alternative water resource for irrigation of the green belt.

Effect of irrigation with treated wastewater on bermudagrass (Cynodon dactylon (L.) Pers.) production and soil characteristics and estimation of plant nutritional input.

In recent years, climate change has greatly affected rainfall and air temperature levels leading to a reduction in water resources in Southern Europe. This fact has emphasized the need to focus on the use of non-conventional water resources for agricultural irrigation. The reuse of treated wastewater (TWW) can represent a sustainable solution, reducing the consumption of freshwater (FW) and the need for mineral fertilisers. The main aim of this study was to assess, in a three-year period, the effects of TWW irrigation compared to FW on the biomass production of bermudagrass [Cynodon dactylon (L.) Pers.] plants and soil characteristics and to estimate the nutritional input provided by TWW irrigation. TWW was obtained by a constructed wetland system (CWs) which was used to treat urban wastewater. The system had a total surface area of 100 m2. An experimental field of bermudagrass was set up close to the system in a Sicilian location (Italy), using a split-plot design for a two-factor experiment with three replications. Results highlighted a high organic pollutant removal [five days biochemical oxygen demand (BOD5): 61%, chemical oxygen demand (COD): 65%] and a good efficiency in nutrients [total nitrogen (TN): 50%, total phosphorus (TP): 42%] of the CWs. Plants irrigated with TWW showed higher dry aboveground dry-weight (1259.3 kg ha-1) than those irrigated with FW (942.2 kg ha-1), on average. TWW irrigation approximately allowed a saving of 50.0 kg TN ha-1 year-1, 24.0 kg TP ha-1 year-1 and 29.0 kg K ha-1 year-1 on average with respect to commonly used N-P-K fertilisation programme for bermudagrass in the Mediterranean region. Soil salinity increased significantly (p ≤ 0.01) over the years and was detected to be higher in TWW-irrigated plots (+6.34%) in comparison with FW-irrigated plots. Our findings demonstrate that medium-term TWW irrigation increases the biomass production of bermudagrass turf and contributes to save significant amounts of nutrients, providing a series of agronomic and environmental benefits.

Seasonal analysis of groundwater samples to identify water quality index and comparative statistical analysis of Hunsur Taluk, Mysuru, Karnataka, India

Groundwater quality assessment is critical for maintaining freshwater sources in semi-arid and dry environments, which is critical for long-term development. Water quality control authorities can regulate the use of water for agriculture or drinking implementations based on groundwater quality in various areas, as nearly 85% of India's population is reliant on groundwater for domestic and irrigation needs, particularly as a source of drinking in rural areas. From Hunsur taluk, Mysore district, Karnataka, India, this study explores and identifies potential places for pumping groundwater for drinking and irrigation. An analysis of groundwater quality was conducted by analyzing the Water Quality Index (WQI) determined from 30 wells during two seasons of the year 2019, namely Pre-Monsoon and Post-Monsoon. The identification of the quality of water resources for irrigation and drinking purposes can be determined with the help of the WQI. It’s extremely useful for classifying water quality considering the standard-based classification of water as excellent, good, poor, very poor, or unsuitable for drinking. By using the Weighted Arithmetic Index method calculated using the groundwater samples collected data for the study, reported ‘excellent water’ ranges between 80 and 83.33 and ‘good water’ between 20 and 16.67, and never found ‘poor water.’ The IWQ index for the study area has been reported to be in the average range of 17.35–65.64. This paper highlights the physico-chemical parameters assess water quality in comparison with climatology.

MEASURING ECONOMIC EFFICIENCY OF WHEAT CROP PRODUCERS IN DESERT AREAS WHO ADOPT PIVOT IRRIGATION TECHNOLOGY AND WHO DO NOT ADOPT FOR THE SEASON 2020-2021

The aimed of research was to make a comparison of the economic efficiency of wheat crop producers in the desert areas of Karbala governorate for adopters of pivot irrigation technology and those who do not adopt by measuring the economic efficiency and its components (technical and allocative) using data envelopment analysis (DEA). Through the quantities and prices of resources and estimation of the surplus and deficit quantities of the resources used to actually produce the wheat crop and the quantities achieved for efficiency and by focusing on the irrigation water resource and based on field data for a random sample. The sample size for wheat producers in the pivot irrigation system was (100) farmers out of (571) farmers in Ain Al-Tamr district according to the agricultural plan of the Karbala Agriculture directorate with a sample of wheat crop producers in the tourist irrigation system (100) farmers Out of (178) farmers in Al-Hur district according to the agricultural plan of the Karbala agriculture directorate through direct interviews with farmers, By analyzing the data envelopment of the research sample, it was found that the farms under the pivot irrigation system achieved full technical efficiency and the stability of the return to scale by 22% of the total sample, while the farms under the pivot irrigation system achieved a percentage of 0.5% This indicates the importance of the pivot sprinkler irrigation technique in reducing the resources used to achieve complete technical efficiency, and the most important of these resources is the irrigation water resource. The average allocative efficiency was (0.82) and economic efficiency (0.72) in the center pivot irrigation system, Due to the good exploitation of the resources used in production, these farms can become more efficient if the support of modern technologies in agricultural production is increased, which reduces production costs and raises the level of allocative and economic efficiency, By estimating the size of the economic resources and the amount of surplus or deficit of resources to produce the wheat crop for the research sample, It was found that there are surplus quantities of productive resources used in the production of the wheat crop (cultivated areas, seeds, dab fertilizer, urea fertilizer, pesticides, irrigation water, mechanized work) under the tourist irrigation system compared to the farms operating under the pivot irrigation system.

The impact of climate change on the availability of irrigation water at the rift valley lakes basin in Southern Ethiopia: A review

Agriculture is one of the foremost climate-responsive businesses, with open-air production systems sensitive to temperature and rainfall. This paper reviews recent literature and assesses the impact of climate change on the accessibility of water resources for irrigation. The paper critically reviews recent research findings on climate change's effect on the potential of surface water and groundwater for irrigation in Ethiopia's south rift valley (Abaya-Chamo) Sub-basin. Surface water in the south rift valley Ethiopia sub-basin, including the Abaya and Chamo lakes, is estimated to be just over 5,718 million m3yr-1. Finally, the implications for future study and development are emphasized. The effect of climate change (rainfall and temperature) on the water in the Abaya-Chamo lakes feeder Rivers is different for the near future (2021–2050) and extreme future (2071–2100) time using the RCP 8.5 scenario. Overall, findings show that the availability of water resources for irrigation purposes in the south rift valley Ethiopia sub-basin will be more vulnerable to changes in rainfall and temperature. In conclusion, Stream flow future projection (%) for each feeder river Bilate, Kulfo, Gidabo, and Hare are -9.07, -11.24, 3.89, 4.135, − 0.95, − 1.5, 13.4, and 15.4% respectively

Ion Exchange Resins to Reduce Boron in Desalinated Seawater for Irrigation in Southeastern Spain

Desalinated seawater (DSW) can provide water resources for irrigation in coastal regions where freshwater is scarce. Reverse osmosis (RO) is the most common technique to obtain DSW worldwide. Nevertheless, using DSW for irrigation could pose an agronomic risk as RO permeates may have a boron concentration above the phytotoxicity thresholds of certain crops, such as woody crops (0.5 to 1.0 mg/L). In this study, an on-farm ion exchange resin system with an average flow of 1 m3/h, designed to reduce the boron concentration of DSW, was evaluated from a technical and economic perspective. The impact of variations in the feed water and operating temperatures on the boron reduction process was assessed. The results show that the system can provide an outflow with a boron concentration below the threshold of 0.5 mg/L over 92 h of operation, with boron rejections of up to 99% during the first 41 h. The estimated cost of boron removal with the on-farm system of the trial was EUR 0.992/m3. However, this cost is expected to decrease to EUR 0.226/m3 for a commercial ion exchange resin (IX) plant (20 m3/h), highlighting the importance of the scale factor. Our results provide novel guidance on the viability of using boron removal IX systems for farms irrigated with DSW, when it is provided by coastal plants with boron concentrations above the crop tolerance.

Irrigation strategies in production of cherry tomatoes under water scarcity conditions

ABSTRACT Controlled water deficit in the phenological phases of cherry tomato can be used without significantly impairing crop yield. The objective was to determine the coefficients of sensitivity to water deficit in cherry tomatoes and to understand the effects of this deficit in agronomic variables and water use efficiency for different irrigation strategies based on phenological stages. The experimental design used was randomized blocks in a split-plot scheme, with four replicates. The primary treatments distributed in the plots were as follows: control without induction of water deficit (W1) and induction of water deficit in the vegetative stage (W2), in the flowering stage (W3), in the fruiting stage (W4), in the maturation stage (W5), and in all phenological stages (W6). The secondary treatments comprised two cherry tomato cultivars, orange and red, placed in the subplots. Water deficit was established at 50% of crop evapotranspiration. Cherry tomato is recommended for production in semiarid regions owing to their adaptability to controlled water deficit based on the coefficient of sensitivity to water deficit, which assists in the management of water resources for irrigation and the maintenance of crop productivity. The vegetative stage is recommended for the deficit irrigation strategy. However, water deficit should not be implemented in the flowering stage, which is considered the most critical stage for the application of water deficit in both cultivars.

An Analysis of Water Use Efficiency of Staple Grain Productions in China: Based on the Crop Water Footprints at Provincial Level

This article analyzed the water use efficiency of China’s staple grain productions (maize, rice, and wheat). This research calculated the water footprints of crop production using the CROPWAT model based on reported water use in 2000 and during 2015–2019, and both green and blue water footprints were calculated. The results showed that compared to 2000 water use efficiency of crop production for maize, rice and wheat during 2015–2019 were increased by about 12.4%, 10.8%, and 2.5% respectively. The current spatial structure of the stable grain industry that makes up grain production regions are concentrated in northern China, then grains are distributed across China (North-to-South Grain Transportation). This has advantages in the increase of agricultural water productivity. This research indicated that agricultural policies should further consider an advance of regional grain production, along with the optimization of transportation channels for stable grains to increase irrigation water use efficiency. The establishment of staple grain production in designated areas not only ensures China’s food security, but also promotes the sustainable use of irrigation water resources.

Temporal and spatial variation and driving factors of water consumption in the middle Heihe river basin before and after the implementation of the"97 water diversion scheme"

Irrational allocation of irrigation water resources aggravates water shortages, affecting the sustainable development of agriculture, especially in arid regions. The expansion of the cultivated area in the middle Heihe river basin (HRB) will not necessarily increase the water consumption, despite the increase in the water-saving irrigation area. In this study, the temporal and spatial distribution, and the driving factors related to water consumption, including evapotranspiration (ET), transpiration (T), evapotranspiration ratio (T/ET), and precipitation deficit (ET-P), were investigated in the middle HRB using linear trend, piecewise fitting, and multiple linear regression method. The results show that the "97 WDS" has prominent impacts on the temporal and spatial trends and the driving factors in ET and T in the middle HRB. Water consumption does not necessarily increase under the centralized water allocation with improved irrigation efficiency and increased cultivated area. The result provides new evidence for increasing T/ET to decrease water consumption in response to the expanding cultivated area, while helping decision-makers to reduce water consumption in the middle HRB, and evaluate “97 WDS”.

Taper and individual tree volume equations of Eucalyptus varieties under contrasting irrigation regimes

Background: Compatible taper and volume equations are key for traditional growth and yield and current process-based or hybrid models. However, most equations do not consider variables such as genotype, water regime and their interaction, limiting the development of general equations for species or regions. Our research investigated taper and individual tree volume equations for eight Eucalyptus genotypes (E. nitens, E. badjensis, E. smithii, E. camaldulensis x globulus and two varieties of low and high productivity of E. globulus and E. nitens x globulus), all materials are growing under summer irrigated vs. no irrigated conditions. Methods: A 7-year old Eucalyptus plantation experiment was sampled considering four representative trees per genotype x water regime combination treatment. Four non-linear taper equations were evaluated: Kozak (2004), Kozak et al. (1969), Ormerod (1973) and Max and Burkhart (1976). In addition, total and merchantable volume was evaluated with the Schumacher and Hall (1933) equation. The effect of genotype, irrigation regime and interaction were evaluated for each equation. Then, the best taper equation was selected from adjusted coefficient of determination, mean square error, and AIC and BIC parameters. Finally, the validation of evaluations was carried out with the Leave-One-Out Jackknife method. Results: Genotype, irrigation regime, or the interaction were not statistically significant for all evaluated taper - volume equations and a generalised model equation was obtained. The best taper equation was Kozak (2004) which showed the best fit and adaptation to irregular boles. Regarding volume equations, all showed a trend to underestimate volume (total and merchantable) in trees with a volume greater than 0.22 m3. Validation of the equations showed reduced bias suggesting that the equations can be used to predict taper and volume regardless of Eucalyptus genotype x irrigation regimen combinations. Conclusions: Our results suggest a negligible or minor effect of irrigation (water resource availability) and genotype (for tested taxas and genotypes) on taper and individual tree volume equations. A generalised taper and volume equation (total and merchantable) may be used for all tested genotypes, regardless of water regime (site water availability). This generalised model would simplify Eucalyptus estimates required for stand management and projection.

Practice and research on water-saving water management model in Gaoyou irrigation district under South–North Water Transfer project situation

In order to meet the needs of the development of limited water supply in South–North Water Transfer Project, Gaoyou irrigation district, with the goal of realizing the modernization of irrigation district, keeps pace with the times, actively explores a new water-saving management model, reforms the water management system, and optimizes the dispatching of water sources, establishing scientific management system and good operation mechanism of irrigation district, realizing optimal allocation and efficient utilization of irrigation water resources in Irrigation district, and making irrigation district on the road of sustainable development of benign operation, significant water-saving benefits, irrigation benefits and social benefits have been achieved.