Irrigation In Region Research Articles

Thirty years of partnerships to achieve sustainable irrigation through Shepparton Irrigation Region Land and Water Management Plan

AbstractThe Shepparton Irrigation Region (SIR) is an environmentally and economically significant area in northern Victoria of Australia covering 500,000 ha. The 1990–2020 Shepparton Irrigation Region Land and Water Management Plan (SIRLWMP) was developed in the late 1980s due to community alarm around increasing salinity and groundwater tables. The regional community (with the support of government, farmers and technical experts) started implementing the plan in 1990. The plan was unique and innovative in Australia in its approach to taking a long‐term view of environmental sustainability. A long‐term and adaptive partnership approach across all levels was vital because environmental problems did not always become apparent in the short term. All of the partners involved in the plan learned to persist and adapt their approach to build resilience in the socio‐economic systems. The SIRLWMP has enabled many serious challenges to be successfully navigated and adapted to including extreme climate events, changing land use and community demographics. Each of these challenges required the ongoing collaboration of many partners to continuously improve the direction and achievements of the SIRLWMP. A 2020 review of the achievements of the 30 years of implementation showed the quantifiable breadth and depth of achievements against the plan's goals. However, there is still more work to do, and the SIRLWMP continues beyond 2020 in a challenging environment. It is expected that partners would continue to work together and continue to talk through difficult issues—because this is how real change happens.

Geospatial and temporal assessment of the variability of soil organic matter and electrical conductivity in irrigated semi-arid area

ABSTRACT A good understanding of the dynamics of soil organic matter and electrical conductivity, in space and time dimension, is crucial for better agricultural and environmental management. This understanding is more required especially in an irrigated semi-arid region such as Doukkala plain in western of Morocco. To assess the status and dynamics of these two soils parameters in such area, in this study, we collected 100 soil samples at two depths (0–20 and 20–40) and over two successive years (2017 and 2018) using a GPS. Then we developed eight ordinary kriging models to produce digital soil maps. The findings indicate that the low content of organic matter in the soils investigated may have a negative impact on soil quality and productivity. Nonetheless, its increasing in the second year could be a sign of future improvement. Salinization of soils, on the other hand, is a continual process that occurs from year to year, whether in the superficial layer or the layer below. This alarming situation must be seriously taken into account in the plans and strategies of decision makers involved in agricultural and environmental policy in order to reduce soil degradation and preserve its quality and productive potential for sustainable food security.

Bioaccumulation and risk assessment of potential toxic elements in the soil-vegetable system as influenced by historical wastewater irrigation

To investigate the pollution status and probable health risk of potential toxic elements (PTEs) in soil and vegetables in historical wastewater irrigation region, eight types of vegetables (n = 73) and corresponding soils were collected to determine the contents of Pb, Cd, Cu, Zn, Ni and Cr, and their potential health risk to local vegetable consumers. The results showed that the mean contents of Pb, Cd, Cu, Zn, Ni and Cr in these soils were 39.72, 1.06, 38.47, 255.00, 27.45 and 61.83 mg/kg, respectively, with Cd exceeding the national standard of China (0.6 mg/kg, GB 15618–2018). Nemerow integrated pollution indices revealed that more than 50% of these soils were slightly or moderately polluted. The activity ratios of Pb, Cd, Cu and Zn ranged from 0.18 to 0.26, which was much higher than that of Ni and Cr. The average PTEs in vegetables were all within the limitation of China or FAO/WHO (except for Pb). However, the PTEs accumulation capacity in different vegetables varied greatly, with the bioaccumulation factor of cilantro (0.023, 0.232, 0.031, 0.063, 0.009 and 0.007 for Pb, Cd, Cu, Zn, Ni and Cr) and white radish (0.004, 0.058, 0.008, 0.021, 0.003 and 0.002 for Pb, Cd, Cu, Zn, Ni and Cr) being the highest and lowest, respectively. Health risk assessment revealed that local residents suffered both non-carcinogenic and carcinogenic risk, with the hazard index (HI) ranging from 0.73 to 2.45 and 2.02–6.53, and the target carcinogenic risk (TCR) ranging from 2.22 × 10−3 to 5.92 × 10−3 and 6.67 × 10−3 to 1.70 × 10−2 for adults and children, respectively. Pb and Cd contributed more than 62.37% of the HI, and Cd contributed more than 79.42% of the TCR. These results indicate that historical wastewater irrigation has a long-term impact on local food safety and potentially adverse consequences for human health.

Evaluation of the Suitability of the Euphrates River water for Drinking and Irrigation purposes in Haditha City, Western Iraq

The supply of freshwater is essential to life, socio-economic development, and political stability in the Middle East. Recently, Iraq's rivers have experienced extreme shortage water scarcity as a result of climate change, as evidenced by the rarity of rainfall and high temperatures. To assess the Euphrates river water for drinking and irrigation uses in Haditha city, Ten water samples were collected in the study region and analyzed for major ions. It was established that water samples in the study region are considered freshwater, low enrichment of salts, and slightly alkaline water. Piper diagram indicates the overall samples belong to class1 (Mg 2+, Ca 2+, SO4 2-, Cl -) and category I (Ca 2+ - Mg 2+ and SO4 2- - Cl -), calcium chloride type (permanent hardness). The Water Quality Index shows that water samples are suitable for drinking purposes. All water sample is suitable for irrigation in the study region. 

Optimization of Irrigation Water to Maximize Transplanted Aman Rice Production in Selected Areas of Bangladesh

In rainfed and irrigated agriculture, optimization of irrigation scheduling is very essential to maximize the crop production using the limited of agricultural water resources. A study was conducted to estimate requirement of irrigation and its scheduling of T. Aman (wet season) rice in the Northwest and Southeast region of Bangladesh using CROPWAT model. This paper utilized the daily rainfall and reference evapotranspiration data sets, obtained from seven weather stations for the period of 1981 to 2015. Effective rainfall and reference crop evapotranspiration (ETo) were calculated using the USDA Soil Conservation method and Penman-Monteith method, respectively. The simulation model of this explored the appropriate transplanting date to utilize maximum rainwater and to avoid supplemental irrigation. Four transplanting dates 15 July, 30 July, 15 August and 30 August were considered for transplanting T. Aman rice in the study areas. The optimization results showed that the water requirement was lower of the rice crop transplanting on 15 July in all locations due to higher effective rainfall. No supplemental irrigation was required for T. Aman cultivation transplanted on 30 July in Rangpur, Dinajpur, Bogura and Mymensingh regions since rainfall was sufficient to meet the demand of the crop. Therefore, this period was found for suitable and recommended for transplanting of T. Aman rice in these four locations. Transplanting after 30 July in these four locations needed supplemental irrigations. This study also revealed that 30 July transplanting required one supplemental irrigation in Jashore and Rajshahi regions due to insufficient rainfall. This period was also considered as the appropriate transplanting time in these two locations. However, in Pabna, one supplemental irrigation must be applied for T. Aman even transplanting on 15 July owing to in adequate rainfall. Irrigation requirement and number of irrigations were gradually increased with delaying the transplanting time. Early transplanting demanded less irrigation than late transplanting. Bangladesh Rice J. 25 (2) : 11-20, 2021

Vegetation Change and Eco-Environmental Quality Evaluation in the Loess Plateau of China from 2000 to 2020

Vegetation change and ecological quality of the Loess Plateau (LP) are directly related to ecological protection and high-quality development of the Yellow River Basin. Based on LP ecological zoning and multisource remote sensing data, we analyzed vegetation change and its relationship with climate, terrestrial water storage (TWS), and land use/cover change from 2000 to 2020, using the normalized difference vegetation index (NDVI), fraction of vegetation cover (FVC), and net primary productivity (NPP). And ecological environmental quality was evaluated based on the remote sensing ecological index (RSEI). The results showed that the spatial distribution pattern of NDVI, FVC and NPP decreased from southeast to northwest in the LP as a whole. Vegetation in the LP recovered significantly, and NDVI, FVC, and NPP showed significant increases of 35.66%, 34%, and 54.69%, respectively. The average NDVI and FVC in the earth–rocky mountainous region and river valley plain region (Area D) were the highest, but the growth rate was the slowest. The average NDVI, FVC, and growth rates in the loess hilly and gully regions (Area B) were slightly higher than those in the loess sorghum gully region (Area A). The average NDVI, FVC, and NPP in the sandy land and agricultural irrigation regions (Area C) were the lowest but showed significant increase. RSEI in most LP areas changed from poor to medium, increasing by 43.45%. Precipitation is the basic factor affecting vegetation cover pattern, with the increase (40.79 mm/10a) promoting vegetation restoration in the LP. Vegetation restoration lost much TWS (−0.6 mm/month), and Area D had the highest average NDVI, FVC, and NPP but the largest TWS loss. Anthropogenic land use/cover change (LUCC) (decrease in cultivated land and unused land; increase in forest, grassland, and construction land) is the primary factor affecting LP vegetation change. This study provides a scientific reference for further vegetation restoration in the LP.

Effects of Planting and Nitrogen Application Patterns on Alfalfa Yield, Quality, Water–Nitrogen Use Efficiency, and Economic Benefits in the Yellow River Irrigation Region of Gansu Province, China

Appropriate planting and nitrogen application patterns to support high-quality production of cultivated forage in light of issues of water scarcity, extensive field husbandry, and low productivity in cultivated grassland planting areas were investigated in this study. Using Medicago sativa L. (alfalfa) as the research object, this study analyzed the effects of planting patterns (conventional flat planting (FP) and ridge culture with film mulching (RM)) and nitrogen level (N0: 0 kg·ha−1, N1: 80 kg·ha−1, N2: 160 kg·ha−1, N3: 240 kg·ha−1) on the growth, yield, quality (crude protein content (CP), acid detergent fiber content (ADF), neutral detergent fiber content (NDF), and relative feeding value (RFV)), the water–nitrogen use efficiency, and economic benefits (EB) of alfalfa in the year of establishment. Results demonstrated that (1) RM might greatly increase the growth of alfalfa when compared to FP. The plant height, stem diameter, and leaf:stem ratio of alfalfa all increased under the same planting patterns before decreasing as the nitrogen application rate (NAR) increased. (2) Appropriate NAR combined with RM could improve the yield and quality of alfalfa. Compared with other treatments, the yield, CP, and RFV under RMN2 treatment increased by 5.9~84.9%, 4.9~28.6%, and 19.6~49.3%, respectively, and the ADF and NDF decreased by 14.0~27.6% and 13.0~26.1%, respectively. (3) Under the same nitrogen level, RM showed better performance than FP in terms of water use efficiency (WUE), irrigation water use efficiency (IWUE), precipitation use efficiency (PUE), partial factor productivity of nitrogen (PFPN), agronomic nitrogen use efficiency (ANUE), and EB of alfalfa. Under the same planting pattern, PFPN decreased as the NAR increased, while WUE, IWUE, PUE, ANUE, and EB first increased and then decreased as the NAR increased and reached a maximum value under the N2 condition. In conclusion, the RM planting pattern combined with a nitrogen level of 160 kg·ha−1 can significantly promote alfalfa growth as well as the yield, quality, water–nitrogen use efficiency, and EB of alfalfa, making it a suitable planting management mode for alfalfa production in the Yellow River irrigation region in Gansu Province, China and areas with similar climate.

Effect of Soil Moisture Deficit on Aerobic Rice in Temperate Australia

Declining water availability is pressing rice growers to adopt water-saving irrigation practices such as aerobic rice to maintain profitability per megalitre (ML) of water input. Irrigators require well-defined irrigation thresholds to initiate irrigation to maximise water productivity. Such thresholds do not exist for temperate rice regions. Adopting a strategy that has been reported to succeed in non-temperate environments may fail in temperate climates, and therefore, needs investigation. This study aimed to investigate, in a temperate Australian environment, the effect of increasing soil moisture deficit during the rice vegetative period on crop physiological development, grain yield and water productivity. The study was conducted in a commercial farm using a randomised complete block design in the 2020/21 and 2021/22 growing seasons. Automated gravity surface irrigation technologies were adopted to enable high-frequency irrigation. Extending soil moisture deficit beyond 15 kPa was found to significantly delay panicle initiation by at least 13–14 days, exposing rice to cold temperatures in Year 1 during the cold-sensitive early pollen microspore period. This reduced yield by up to 55% (4.5 t/ha) compared to the 15 kPa treatment that was not impacted by cold sterility. In the absence of cold sterility, irrigated water productivity and total water productivity ranged between 1.02 and 1.61 t/ML, and 0.84 and 0.93 t/ML, respectively. The highest yields (8.1 and 7.5 t/ha) were achieved irrigating at a soil tension of 15 kPa in growing seasons 2020/21 and 2021/22. This research demonstrates that sound water productivity can be achieved with aerobic rice cultivation in temperate climates, providing cold temperatures during early pollen microspore are avoided. The quantification of the delay in crop development caused by increasing soil moisture deficit provides rice farmers greater confidence in determining the irrigation strategy and timing of pre-emergent irrigation in regions at risk of cold sterility. However, due to the high labour demand associated with aerobic rice, the adoption of aerobic rice at a commercial scale in this Australian environment is unlikely without adopting automated irrigation technology.

Quantifying the Contributions of Regional Human Activities and Global Climate Change to the Regional Climate in a Typical Mountain‐Oasis‐Desert System of Arid Central Asia From 1979 to 2018

AbstractMany studies have examined the influence of global climate change and regional human activities on the climate of arid Central Asia, but their separate contributions have rarely been reported due to lack of a comprehensive description of regional human activities, especially the irrigation process, in the model. In this study, we conducted two sets of 40‐year continuous simulations with and without human activities to distinguish the effects of regional human activities and global climate change on the surface air temperature (T2), humidity (Q2) and precipitation of a typical mountain‐oasis‐desert system in northern Tianshan by using a modified WRF‐Noah model with irrigation processes. The results indicated that the annual average T2, Q2 and convective precipitation during the past 40 years increased by 0.393°C, 0.063 g/kg and 0.014 mm/d, respectively, and the annual average large‐scale precipitation and total annual average precipitation decreased by approximately −0.017 and −0.003 mm/d, respectively. Regional human activities contributed 52.63% and 50.38% of the change in large‐scale precipitation and total precipitation, respectively, while global climate change accounted for more than 80% of the change in temperature and humidity. Among the human activities, irrigation had the largest impact on T2/Q2 over the local irrigation region and on precipitation in the upstream Tianshan mountainous area. However, for the whole region, the increase in the green vegetation fraction was the core factor that impacted the regional climate. Our results can deepen the understanding of the attribution and mechanism of climate change and provide water and heat change references for other mountain‐oasis‐desert systems in arid endorheic regions.

Evaluation of the effect of soil salinity on the crop coefficient (Kc) for cotton (Gossypium hirsutum L.) under mulched drip irrigation in arid regions

Evaluation of the effect of soil salinity on the crop coefficient (Kc) for cotton (Gossypium hirsutum L.) under mulched drip irrigation in arid regions

An Agroecological Analysis of Livestock Wealth in India

This study aims to analyze the livestock population dynamics, adoption pattern of livestock and infrastructure facilities across different agroecological regions of India. The results revealed that more than 50 per cent of all livestock species were found in rain-fed areas. In irrigated region, 36 per cent of the livestock population depended upon 15 per cent of the geographical area. The cattle population growth rate declined for all regions because of a faster decline in indigenous cattle in all the agroecological regions. The number of crossbred cattle increased from 26 to 44 million among the cattle population at the India level. It may be due to the acceptance of insemination techniques with the expectation of high milk yield. Whereas, in irrigated region, the situation was very different, with a marginal increase in the share of crossbred cows. The findings indicated that India’s large and uniquely structured livestock sector was growing with compound annual growth of 4.3 per cent. For the sustainable development of the sector, suitable efforts should be taken to improve the genetic potential of indigenous cattle and buffalo and enhance the milk yield of crossbred cows by supportive technical, institutional and policy initiatives

Evaluation of the microbiological quality of water for human consumption and irrigation in regions of Alagoas

Well water is one of the most accessible and indispensable sources for populations that do not have access to the public water supply network. This must be free from pathogenic microorganisms so that it is considered of good quality for consumption. The lack of monitoring of water sources and the population's ignorance of the causes and problems associated with contamination can lead people to acquire several waterborne diseases. This study aimed to evaluate the presence of thermotolerant coliforms in water used for human consumption in seven wells in the state of Alagoas, using the most probable number (MPN) technique. Seven water samples were collected and analyzed in two communities, 5 in a community located in the Alagoas Forest zone and 2 in the Alagoas wild. According to the microbiological analyzes carried out in this work, the results showed that the water used by communities in the interior of the state of Alagoas, was identified as an important risk factor to the health of the population, since all water sources analyzed present indices of total coliforms and E. coli above those allowed for human consumption. Regarding irrigation, only 43% of the samples are suitable for irrigation.

Mineral composition and production of guava under salt stress and salicylic acid.

The limitation in the quality of water sources for irrigation in the semi-arid region of northeastern Brazil is increasingly present, so it is necessary to use water with high concentrations of salts for agricultural production, which makes the use of elicitors essential to mitigate the harmful effects of salinity on plants. Given the above, the objective of this study was to evaluate the effects of foliar application of salicylic acid on the mineral composition and production of guava plants under salt stress conditions in the post-grafting phase. The experiment was carried out under greenhouse conditions, in a randomized block design, in a 2 × 4 factorial scheme, with two levels of electrical conductivity of irrigation water (0.6 and 3.2 dS m-1) and four concentrations of salicylic acid (0, 1.2, 2.4, and 3.6 mM), with three replicates. During the flowering stage of guava, N, P, and K contents accumulated in the leaves according to the following order of concentration: N > K > P. Foliar application of 1.2 mM of salicylic acid increases the leaf contents of N, P, and K in guava plants grown under irrigation with water of 0.6 dS m-1. Water salinity of 3.2 dS m-1 reduces the growth and production components of guava plants.

Cultivo hidropônico de quiabeiro utilizando soluções nutritivas salinas sob aplicação de ácido salicílico

ABSTRACT The limited availability of low-salinity water for irrigation in the Northeastern semi-arid region has restricted food production, making it necessary to use strategies to reduce the effects of salt stress on plants. Among the alternatives, the foliar application of salicylic acid stands out. In this context, the objective of this study was to evaluate the effects of foliar application of salicylic acid in mitigating salt stress on the gas exchange, chlorophyll a fluorescence, photosynthetic pigments, and growth of ‘Canindé’ okra in a hydroponic system. The experiment was carried out in a greenhouse, in Pombal - PB, using the Nutrient Film Technique - NFT hydroponic system. The experimental design used was completely randomized in a split-plot scheme, with four levels of electrical conductivity of the nutrient solution - ECns (2.1, 3.6, 5.1, and 6.6 dS m-1) as the plots and four concentrations of salicylic acid - SA (0, 1.2, 2.4, and 3.6 mM) as the subplots, with four replicates and two plants per plot. SA concentration of 3.6 mM was able to minimize the effect of nutrient solution salinity on chlorophyll a fluorescence and increase the synthesis of chlorophyll b in okra plants, 34 days after transplanting. Nutrient solution salinity above 2.1 dS m-1 negatively affected gas exchange, relative water content, photosynthetic pigments, and growth and increased electrolyte leakage in the leaf blade of okra plants.

УРОЖАЙНОСТЬ ОЗИМОЙ ПШЕНИЦЫ ПРИ РАЗЛИЧНЫХ ТЕХНОЛОГИЯХ ОРОШЕНИЯ И МИНЕРАЛЬНОГО ПИТАНИЯ В УСЛОВИЯХ ИЗМЕНЯЮЩЕГОСЯ КЛИМАТА В ЦЕНТРАЛЬНОЙ ОРОШАЕМОЙ ЗОНЕ РОСТОВСКОЙ ОБЛАСТИ

Purpose: to study the impact of various irrigation technologies and the mineral fertilizers application on winter wheat productivity for years with different climatic conditions and to study changes in climatic indicators of the Central irrigated zone Rostov region for the period 2012–2021. Materials and methods. Field research in 2019–2021 were carried out in Bagaevsky district Rostov region on irrigated lands. In the experiment, three options for irrigation technology and three options for the technology of mineral nutrition of winter wheat were studied. According to soil texture of the experimental plot throughout the profile, they are represented mainly by heavy loams. The humus content in the arable layer (0.3 m) is 3.7 %. The climate of the study area is characterized as arid. In the course of the research, the moisture deposits in the soil layer of 0–100 cm were determined by the phases of winter wheat vegetation, the leaf area duration was taken into account, and the winter wheat yield was carried out according to the experimental options. Results. The use of precision irrigation technology made it possible to ensure moisture reserves in the heading phase at the level of 102.4–110.4 mm. Precision irrigation technology without and with the use of various technologies for applying mineral fertilizers ensured maximum yields of up to 4.83–8.69 t/ha. Conclusions. The advantage of precision irrigation technology and the application of mineral fertilizers, which ensures the greatest growth of the leaf area duration of winter wheat and contributes to obtaining maximum yields, even under conditions of scarcity of available water resources during the critical period of winter wheat vegetation, has been determined.

Rop diversification pattern in Haryana: A comparative study of organic and inorganic farmers

The adoption of organic farming helps increase agriculture's profitability, enhancing food'snutritional value and sustaining the health of soils, ecosystems, and people. It became popularin Haryana during the recent period. The present study analyses the salient features of the adop-tion process of organic farming, and its impact on cropping patterns, crop combinations, anddiversification. It is a primary data-based comparative study of organic and inorganic farmers ofthe state. The data has been collected from 234 farm households with the help of a structured questionnaire. The study analyses the main factors in the adoption of organic farming in the state.The comparisons of cropping patterns, crop combination, and crop diversification have been doneby applying statistical techniques such as the Doi method, and Herfindahl Index. The study bringsout that farmers having small land holdings but higher education levels prefer organic farming.Though organic farming is carried out at a small scale in the state, it has been pursued earnestly asabout half of the organic farmers devote more than three-fourths of their land to this form offarming. Organic farmers are found to grow a larger number of crops and have quite a diversified cropping pattern compared to inorganic farmers. There is a perceptible difference in this regard inorganic farming across agro-ecological regions. The lesser irrigated mixed-crop region has muchmore diversified than the wheat-rice region of the eastern parts of the state.

WATER QUALITY OF LAKE KATLABUKH

The soil and thermal resources of the Odessa region allow growing a variety of agricultural crops with a yield much higher than currently obtained. But this is possible only when using irrigation. The southwestern part of the region has such a powerful source of water as the Danube River, from which irrigation is carried out and the lakes Cahul, Yalpug, Katlabukh, China and a number of reservoirs are filled. For a number of reasons, after 2000 the actual amount of irrigated land has decreased significantly. Along with this, the quality of water in reservoirs changes, and sometimes they disappear from the map. At the state level, various programs are being adopted to restore irrigation in the southern regions of Ukraine without understanding the presence and hydrochemical composition of the waters of reservoirs. To do this, it is necessary to conduct a detailed analysis of the presence of water bodies and assess their chemical composition. This work is devoted to one of the sources of water supply for the national economy, namely Lake Katlabukh. Lake Katlabukh is used as the main source of irrigation for three state systems - Suvorivskaya, Izmailskaya and Kislytskaya (formerly Kirovskaya) irrigation systems (IS) and small irrigation areas (SIA) on an area of 16.671 hectares. In addition, the Loschinivske, Kaminske, Banivske and Muravlivske reservoirs were additionally filled with lake waters to irrigate 22063 hectares within the limits of the Loschinivske, Tashbunarske, Muravlivske and Banivske IS and the SIA adjacent to them. The aim of the work is to analyze the hydrochemical state and assess the quality of water according to agronomic criteria over a thirty-year period of one of the lakes, the waters of which have been and continue to be used for irrigation. To solve this problem, materials of hydrochemical observations were collected and processed. The main indicators of anionic and cationic composition, mineralization index and pH are summarized and averaged for every five years from 1991 to 2020. Separately, data for 2021 is given. To assess the quality of water according to agronomic criteria, all indicators were calculated according to the latest methodology. The main reasons for the deterioration of water quality have been identified.

Optimizing Water and Nitrogen Management for Green Pepper (Capsicum annuum L.) under Drip Irrigation in Sub-Tropical Monsoon Climate Regions

Green pepper (Capsicum annuum L.) is one of the major vegetables cultivated in sub-tropical monsoon climate regions. However, with the unreasonable use of water and nitrogen (N) fertilizer, efficient water and N fertilizer management systems need to be identified. The goal of this project was to investigate the coupling effects of different amounts of water and N on green pepper yield, water use efficiency (WUE), as well as N use efficiency (NUE) in sub-tropical monsoon climate regions. The optimum combination of water and N inputs was determined for multi-objective optimization through the multiple regression analysis and the combinations of likelihood functions. The pot experiment was conducted during the green pepper growing seasons (May–September) of 2019 and 2020 in a greenhouse at Nanchang, Jiangxi of China that included three water deficit levels, i.e., mild deficit (W1: 95~80%θFC, %θ field capacity simplified as %θFC), moderate deficit (W2: 80~65%θFC), and severe deficit (W3: 65~50%θFC), and four levels of nitrogen application (Napp) rate, i.e., 6.0 (N1), 3.0 (N2), 1.5 (N3), and 0.0 g plant−1 (N4), for a total of twelve treatments (i.e., 3 × 4) with six replications. Results show that water levels have an extremely significant effect (p < 0.01) on green pepper yield and WUE, but no effect on NUE (p > 0.05). N treatments have significant effects on green pepper yield, WUE, and NUE. Meanwhile, the effects of water levels and N treatment interaction on WUE and NUE were extremely significant (p < 0.01), but varied on yield between the two years. The maximum yields (576.26 and 619.00 g plant−1) occurred when the water level and Napp rate were 80~65%θFC and 6.0 g plant−1. While the water level and Napp rate were 80~65%θFC and 3.0 g plant−1, the WUEs and NUEs reached the maximum, which were 20.14 and 17.71 g L−1, 76.54, and 77.73 g−1 in 2019 and 2020. The dualistic and quadric regression equations of irrigation amount and Napp rate indicated that the yield, WUE and NUE cannot reach the maximum at the same time. By establishing a multiobjective optimization model using combinations of likelihood functions, it was concluded that the water level shall be controlled in 80~65%θFC and the Napp rate is 3.78 g plant−1, which can be used as the suitable strategy of water and N management for the maximum comprehensive benefits of yield, WUE, and NUE for green pepper. The obtained optimum combination of water and N inputs can provide a scientific basis for irrigation and fertilization optimization and management in sub-tropical monsoon climate regions.

Identification of Suitable Sites for Rainwater Harvesting Using GIS in Kandahar Province, Afghanistan

Objectives: This study aims to identify the potential areas for rainwater harvesting in Kandahar, Afghanistan. Methods: This study used GIS-based RS techniques. Satellite images were used to plan multiple thematic layers, such as lithology, slope, land use/cover, stream order, and soil texture. These layers were then converted into raster data using the raster converter feature of the ArcGIS 10.4 program. In order to come up with a site suitability map for water harvesting structure, multicriteria analysis was then carried out on the different layers, each layer’s characteristics were assigned weights as provided by experts in past research reviews. Owing to their power and their respective class weights, different layers were then overlaid. Findings: The findings showed that the catchment was grouped into categories as ’high’, ‘moderate’ and ‘low’ zones with regard to the allocated weighting of different thematic layers using weighted overlay. Twenty zones of rainwater harvesting structures were identified from the WH suitability map for the various structures for water harvesting. The suitability map helped to select water harvesting structures such as percolation tanks, storage tanks, control dams, and stop dams to be installed at the different identified sites. The potential sites of rain water harvesting identified were Shorabak, Boldak, Marrurf, Arghistan-1, Arghistan- 2, Arghistan-3, Khakres, Ghorak, Maiwand-1 and Maiwand-2 in the Kandahar Province Afghanistan. Novelty: These findings indicate that high potential zones would play a key role in the future expansion of the production of drinking water and irrigation in the study region. The suitability map is useful to hydrologists, decision-makers, and planners for quickly identifying areas with the highest potential for harvesting rainwater. Keywords: Rainwater harvesting; ground water; AHP approach; GIS; Kandahar; Afghanistan

Water quality and interaction between groundwater and surface water impacted by agricultural activities in an oasis-desert region

A comprehensive understanding of groundwater dynamics and its interaction with surface water under the influence of agricultural activities is essential for local agriculture, ecology and resident in arid regions, which is poorly understood in arid oasis-desert region. In our study, with emphasis on a comparison of hydrogeochemical characteristics between the oasis (irrigated) and desert (non-irrigated) areas, the water quality and groundwater-surface water interaction of a typical oasis-desert system with a rapid irrigation agriculture development were examined to clarify the effects of agricultural activities on groundwater level and quality using stable isotopic and hydrochemical data of 83 water samples. Results showed that cultivated land area increased by 121.8 % (732.4 km2) during 2000 to 2020, mainly transferring from grassland and bare land. Groundwater EC ranged from 786 to 49,400 μS/cm, with weakly alkaline. Shallow groundwater had a much higher EC than other water components. Stable isotopic and EC values of shallow groundwater in the non-irrigation areas were much greater than those in the irrigation areas, whereas middle groundwater isotopic values were more depleted in the desert than in the oasis. Shallow groundwater EC value was lower in summer, middle groundwater had higher EC in summer. Streamflow and confined water in the study area are suitable for agricultural irrigation, but phreatic water in the oasis is generally not suitable for irrigation at present. The groundwater chemistry was mainly controlled by strong evaporation, dilution, mixing, water-rock interaction and agricultural drainage. Groundwater in the irrigation areas was recharged by ephemeral runoff seepage, irrigation return flow and subsurface lateral inflow. Long-term development of irrigation agriculture (large-scale land reclamation, irrigation and groundwater pumping) in arid region has caused groundwater level decline and salinization, with a strong interaction between phreatic water and surface water. Hence, decreasing irrigation area and groundwater exploitation, carrying out gradual ecological restoration, improving water-saving efficiency and agricultural drainage system would be the viable method to restore groundwater and maintain the oasis-desert ecosystem coexistence in arid regions in the context of climate change.