Furrow Irrigation Research Articles

Profiling bacterial communities of irrigation water and leafy green vegetables produced by small-scale farms and sold in informal settlements in South Africa

Morogo is an African indigenous term used for leafy green vegetables harvested in the wild or cultivated in small-scale farms and consumed by the local populations of the region. Small-scale farmers have gained recognition as important suppliers of morogo to informal settlements. In commercial production systems, leafy green vegetables have increasingly been reported as associated with foodborne pathogens and disease outbreaks. Little is known of the presence of these organisms on leafy green vegetables in the informal unregulated food systems. This study aimed to profile bacterial communities in irrigation water (flooding and overhead irrigation water) and leafy green vegetables (Brassica rapa L. chinensis and Brassica rapa varieties of morogo) to establish the natural bacterial flora at the water-fresh produce interface from five small-scale farms in two provinces in South Africa. Illumina MiSeq high-throughput sequencing showed that each farm exhibited a unique bacterial community composition, with an overall high relative abundance of Proteobacteria, Firmicutes and Actinobacteria, including prominent families such as Burkholderiaceae (48%), Enterobacteriaceae (34%), Bacillales Family XII (8%), Rhodobacteraceae (3%), Micrococcaceae (1.98%) and Pseudomonadaceae (1.79%). Specific Enterobacteriaceae Serratia, Enterobacter, Salmonella, Shigella, Escherichia coli, Buchnera, Citrobacter, Klebsiella and Proteus were identified, in addition to unique communities associated with plant or irrigation water source. These findings suggest that the edible plant microbiome can play an important role as transient contributor to the human gut and has the potential to affect overall health.

Using Film-Mulched Drip Irrigation to Improve the Irrigation Water Productivity of Cotton in the Tarim River Basin, Central Asia

Climate change has significantly influenced water resource patterns in arid regions. Applying effective water-saving measures to improve irrigation efficiency and evaluate their future water-saving capabilities is crucial for ensuring the sustainable development of irrigation agriculture. Based on the daily meteorological data from 15 global climate models (GCMs) in the sixth phase of the Coupled Model Intercomparison Project (CMIP6), this study used the AquaCrop model to perform high-resolution (0.1° × 0.1°) grid simulations of cotton yields and irrigation requirements. The study also investigated the ability of film-mulched drip irrigation (FMDI) to improve future irrigation efficiency under two shared socio-economic pathways (SSP245 and SSP585) in the Tarim River Basin (TRB), Central Asia, from 2025 to 2100. The results showed that the cotton yield and irrigation water productivity (WPI) in the TRB exhibited an upward trend of 13.82 kg/ha/decade (80.68 kg/ha/decade) and 0.015 kg/m3/decade (0.068 kg/m3/decade), respectively, during the study period. The cotton yield and WPI were higher in the northern, northwestern plains, and northeastern intermountain basin areas, where they reach over 4000 kg/ha and 0.8 kg/m3/decade. However, the cotton yield and WPI were lower in the southwestern part of the study area. Therefore, large-scale cotton production was not recommended there. Furthermore, compared to flood irrigation, the use of FMDI can, on average, improve the WPI by approx. 25% and reduce irrigation water requirements by more than 550 m3/ha. Therefore, using FMDI can save a substantial amount of irrigation water in cotton production, which is beneficial for improving irrigation efficiency and ensuring the future stable production of cotton in the TRB. The research results provide a scientific reference for the efficient utilization and management of water resources for cotton production in the TRB and in similar arid regions elsewhere in the world.

Natural Farming Practices Impact on Yield and Macro Nutrient Uptake of Sorghum

The objective of the experiment is to study the effect of different natural farming practices on sorghum yield and nutrient uptake. For this a field experiment was carried out in 2023 at the Eastern block - Field No. NA 02, Tamil Nadu Agricultural University (TNAU), Coimbatore. The experiment included a randomized block design with nine treatments and three replications. Zero Budget Natural Farming techniques were fully implemented, encompassing the use of Ghanajeevamirit as a basal application, treating seeds with Beejamirit, applying Jeevamirit every two weeks via irrigation, practicing intercropping and mulching, and employing Whapasa (Alternate Furrow irrigation). Additionally, both organic and integrated plots were integrated into the approach. Results revealed that application of 50% organic and 50% inorganic treatments with organic pest repellants as ICM (T8) produced noticeably highest grain yield (2781 kg ha-1), stover yield (5682 kg ha-1) and NPK uptake (135.39, 45.09 and 80.49 kg ha-1), which was comparable to T9 ICM using chemical pest repellants. In comparison to natural farming plots, the organic farming plot (T7) showed considerably higher grain yields (2555 kg ha-1), stover yields (5456 kg ha-1) and NPK uptake (122.49, 39.40, and 66.91 kg ha-1). There were considerably greater grain yield (2294 kg ha-1), stover yield (5173 kg ha-1) and NPK uptake (108.32, 34.17, and 56.17 kg ha-1) in complete Natural Farming plot T2, which include all components (B+J+G+M+I+W) compared to control treatment which had considerably lower grain yield (1597 kg ha-1), stover yield (4306 kg ha-1) and NPK uptake rates (58.28, 15.49 and 27.75 kg ha-1).

On-farm water energy food carbon-footprint nexus index for quantitative assessment of integrated resources management for wheat farming in Egypt

To improve the farming efficiency, Egypt has been struggling to narrow the water, energy, and yield gaps owing to exacerbated water shortage. For quantitative diagnosis of farming performance, the paper presented an on-farm water, energy, food, and carbon-footprint (WEFC) nexus index made up of four equally pillars. The arithmetic average preserved the multi-centric approach and equal importance of the four pillars. The index was applied to test and rank 2,042 wheat-based farmer fields in Egypt representing diverse inputs, agronomic and irrigation practices, soil types, and agroecological conditions. The water metric was the ratio of saved water, difference between maximum water consumption recorded in the country and actual water consumption, to the maximum water consumption. Likewise, the energy metric was obtained. The food metric was the ratio of actual yield to maximum yield in the country. The carbon-footprint metric was the ratio of difference between maximum CO2 emission in the country and actual emission to the maximum emission. The index values showed a wide range from 18.69% to 87.33% with a high standard deviation emphasizing the diversity of farming practices, soil types, and agroecological conditions. The highest ten values were recorded in fields with sandy soils, relatively large area, drip irrigation, recommended seeding and fertilization rates, well drainage, weeds removal, and tillage. The drip irrigation system in 51 out of 52 fields had above average value. The lowest ten values were in fields with clay soils and flood irrigation, where 18.7% of 1,780 fields exceeded the above average value. Raised beds with furrow irrigation in 83.15% of 184 fields exceeded the above average value. Fertilization rates of nitrogen and phosphorus in 61% and 53% of fields respectively exceeded the recommended rates with no significant reflection on the food metric. The low index values in fields with flood irrigation were attributed to high water losses causing high water consumption, energy consumption, and CO2 emission. The index was a good indicative of input resources consumption and output production as it varied inversely with water and energy consumption and CO2 emission and proportionally with yield. Since the high-water consumption was the main entry point for low index values in fields with flood irrigation, changing the irrigation to drip system or revisiting the irrigation scheduling and the estimated applied irrigation water amount were recommended. The index can be utilized to quantify the effectiveness of both recommendations and further new site-specific interventions and to assess their impact at scale. The index also recommended land use consolidation where farmers retain ownership of their lands but with cooperative farming.

Improving potential of reactive nitrogen and carbon footprint of intensified greenhouse cucumber-tomato production with optimized drip irrigation with nitrogen reduction strategies

Guaranteeing a robust supply of vegetables is a significant public welfare endeavor. However, the implementation of irrational water and fertilizer regimes in greenhouse vegetable fields (GVF) has resulted in adverse environmental impacts. Therefore, it is crucial to develop water and fertilizer regimes to maintain the productivity of greenhouse vegetables with less carbon (C) and reactive nitrogen (Nr) footprint. A four growing seasons experiment involving the cultivation of cucumbers and tomatoes was conducted in the suburbs of Beijing. The experiment comprised three treatments: flood irrigation with a conventional urea-N application (FN), drip fertigation with a conventional urea-N application (DN), and drip fertigation with a 50% reduction of urea-N application (DRN). The results showed that about 70% of annual N inputs in GVF were surplus, posing a high risk of loss. For the FN treatment, the N budget, Nr loss, Nr footprint per unit of vegetable yield (NrFY), Nr footprint per unit of net return (NrFR), greenhouse gas (GHG) emissions, C footprint per unit of vegetable yield (CFY), C footprint per unit of net return (CFR) were respectively quantified as follows: 1653 kg N ha−1 yr−1, 776 kg N ha−1 yr−1, 4.39 kg N t−1 yr−1, 24.48 kg N ¥10000−1 yr−1, 46548 kg CO2-eq ha−1 yr−1, 262.98 kg CO2-eq t−1 yr−1 and 1467.58 kg CO2-eq ¥10000−1 yr−1. Compared with FN, DN significantly reduced Nr loss (25%), NrFY (24%), NrFR (22%), GHG emissions (6%), CFY (4%), while it increased N surplus (9.7%) and produced lower farmers' net return (¥ 13486 ha−1 yr−1). Concurrently, DRN significantly reduced the N surplus, Nr loss, NrFY and NrFR by ∼35%, decreased the GHG emissions, CFY and CFR by ∼20%, and improved farmers' net return by ¥ 674 ha−1 yr−1 compared to FN treatment. Therefore, this study highlighted that an integrated water and fertilizer regulation strategy (drip irrigation replacing flood irrigation coupled with a 50% reduction in chemical N application) can simultaneously achieve environmental and economic benefits in the context of high N inputs. This contributes to the sustainable development of intensive vegetable cultivation systems.

Irrigation management by a private irrigation operator (PIO) under a fixed‐term management contract: An alternative approach to managing irrigation in Nepal

AbstractMost of the agency‐built surface irrigation systems in Nepal the operation and maintenance (O&M) of which are being managed by irrigation agencies jointly with farmers are not performing satisfactorily. The unreliable delivery of irrigation services to farmers is one of the reasons for this. Thus, the most important challenge in the past and in the present is how to enhance the delivery of irrigation services to farmers.If one examines the private sector management of other public enterprises, they are efficiently delivering services to their clients. Considering this aspect, the government of Nepal recognized that irrigation systems or parts of them may also be managed through private irrigation operators (PIOs) under a fixed‐term management contract to enhance their service delivery.This paper analyses the O&M of jointly managed irrigation systems (JMISs) and suggests that a lack of capacity, accountability and incentive mechanisms on the part of irrigation agencies are the principal causes pertaining to the deficient delivery of irrigation services in them. It further suggests that introducing PIOs in managing the operation and maintenance of part of the JMISs can address these causes. The paper argues that the said PIO approach is viable from financial, technical and managerial perspectives.

Multi-objective decision-making for efficient utilization of water and fertilizer in paddy fields: A case study in Southern China

Effective water and fertilizer management modes (WFMMs) are crucial for mitigating non-point source pollution, enhancing grain quality, and improving resource utilization in paddy fields. Nevertheless, screening WFMMs that can effectively synergize these benefits is challenging, particularly in the wake of climate change. A two-year lysimeter experiment was conducted to investigate the effects of WFMMs on water balance components, nitrogen and phosphorus loss loads, grain yield and quality, and nitrogen utilization efficiency. Four treatments were established, including flooding irrigation (FI) and alternate wetting and drying irrigation (AWD), paired with conventional fertilizers (CF) and sulfur-coated fertilizer (SCF). A multi-criteria evaluation framework was developed to assess the potential values of WFMMs under diverse hydrological conditions using the vertical and horizontal scattering degree method. The results indicated that the AWD regime increased irrigation and drainage by approximately 8% compared to CF during the wet season, while reducing irrigation, percolation, and augmenting capillary rise during the dry season. Irrigation had not a significant effect on rice yield and quality. Compared to CF, AWD significantly increased nitrogen accumulation at maturity and nitrogen recovery efficiency by 20% and 31% on average. The SCF had a significant effect on the nitrogen accumulation at maturity, nitrogen recovery efficiency, N partial factor productivity, yield (increased 8–9% across two years), and protein content (increased ∼8% across two years), but at the cost of higher leachate concentration when compared to CF. Integration of AWD and SCF treatments demonstrates the potential for improved water productivity, yield, and nitrogen utilization efficiency, along with an enhanced ability to purify pollutants. The vertical and horizontal scattering degree method assessment showed that the AWD+SCF treatment exhibits superior performance in water saving, pollution reduction, yield and quality, and nitrogen efficient utilization, which was amplified during the dry season. These findings offer novel perspectives for optimizing WFMMs under varying hydrological conditions in hilly areas of Southern China.

Effect of Drip Irrigation Levels and Weed Management Practices on Quality Parameters and Yield of Turmeric (Curcuma longa L.) under Mango Orchard

A field experiment, aimed to study the effect of drip irrigation levels and weed management practices on quality and productivity of turmeric (Curcuma longa L.) in mango orchard was carried out at Pt. K.L. S. College of Horticulture and Research Station, Rajnandgaon (Chhattisgarh) during two consecutive years (2019-20 and 2020-21). The results indicated that all the quality parameters like total carbohydrate in rhizomes, volatile oil yield in rhizomes, oil yield and curcumin content in turmeric were significantly higher values observed when the crop imposed to drip irrigation at 1.0 Epan and hand weeding thrice at 25, 50 and 75 DAP in 2019-20 and 2020-21. However, flood irrigation at 1.0 Epan and weedy check plot recorded the lowest values of these parameters during both years. The combination of drip irrigation at 1.0 Epan with hand weeding thrice at 25, 50 and 75 DAP recorded significantly the highest fresh rhizomes yield (29.10, 32.40 and 30.75 t ha-1) and cured rhizomes yield (6.58, 6.93 and 6.76 t ha-1) during kharif -rabi 2019-20 and 2020-21and on mean basis, respectively.

Evaluating the differences in irrigation methods for winter wheat under limited irrigation quotas in the water-food-economy nexus in the North China Plain

Quantitatively evaluating the effects of multiple factors on the performance levels of different irrigation methods under a limited water supply in the water-food-economy nexus at the regional scale is of great significance; such evaluations can facilitate the selection of appropriate irrigation methods and schemes to reduce the contradiction between the water shortage and grain production circumstances. In this study, the distributed SWAP-WOFOST (Soil-Water-Atmosphere-Plant-WOrld FOod STudy) model was applied to a typical area of severe deep groundwater overexploitation in the North China Plain. This model was used to simulate various scenarios of sprinkler irrigation (SI) and limited surface irrigation (LSI) under the three limited irrigation quotas (i.e., 75 mm, 150 mm and 225 mm) and to further quantify the differences in crop yield, evapotranspiration and water productivity (WP) between the two irrigation methods by considering three rainfall levels and 66 soil texture profile (STP) types. Then, the impacts of irrigation methods on farmers’ net income were analyzed; the increasing extents of SI implementation scale and workday wage to improve farmers’ net income were estimated according to irrigation, rainfall and soil conditions. Under a specific limited irrigation quota, the yield and WP of winter wheat under LSI were greater than those under SI without fertigation in more than 92% of the 66 STP types under the three rainfall levels, with yield differences mainly in the range of 200–1600 kg hm−2 and WP differences mainly in the range of 0–0.5 kg m−3. In no more than five STP types (e.g., sandy or loamy sandy soil in the five layers), the yield and WP under LSI were lower than those under SI. Relative to the evapotranspiration under LSI, the evapotranspiration under SI did not show the same trend, while the ratio of transpiration to evapotranspiration under SI decreased in more than 98% of the STP types. For different irrigation quotas and rainfall levels, the farmers’ net incomes under SI were 374–1517 yuan hm−2 greater than those under LSI for up to five STP types, and they were 0–3000 yuan hm−2 lower than those under LSI for the other 92% of the STP types. When labor could be saved by more than 8 d hm−2 by improving the implementation scale of SI and the workday wage could increase to more than 100 yuan d−1, SI was recommended to obtain higher farmers’ net income in more STP types in the study area.

A global meta-analysis on surface and drip fertigation for annual crops under different fertilization levels

So far, many studies have examined the effects of surface (FF) and drip (DF) fertigation compared to surface (FC) and drip (DC) irrigation along with fertilization at different levels of fertilizer on crop yield indices, nutrient use efficiency (NUE), and irrigation water productivity (WP); however, each of them have been conducted under different conditions. Because of the scattered results and the lack of a general conclusion from the published results, conducting a meta-analysis as a structured method for arriving at an overall conclusion regarding the effects of different fertigation methods on different indices is essential. This study was conducted to examine the effects of surface and drip fertigation methods and different fertilizer application levels on crop yield, NUE, and WP. To this end, eight global databases of publications (e.g., Scopus and Web of Science) were reviewed. A total of 5494 studies were extracted, of which 32 studies met the entry criteria for the meta-analysis. To assess the effects of fertigation, each study was used to extract the effect sizes for each index. A total of 119 effect sizes were obtained for crop yield, 85 for NUE, and 84 for WP. The meta-analysis results showed that surface and drip fertigation methods increased the average yield by 20%. NUE and WP on an average increased by 26% and 51%, respectively. Based on the reported results, the optimal fertilizer application level is 75% of the recommended dose, which can reduce fertilizer use by 25% without significantly reducing the yield. In general, fertigation can be recommended as an effective operation for improving the proposed indices examined in both surface and drip fertigation methods.

Replacing conventional surface irrigation with micro-irrigation in vegetables can alleviate arsenic toxicity and improve water productivity

Arsenic (As), a heavy metal(loid), is exceedingly hazardous and carcinogenic and harms people, soil, plants, and water. Vegetable consumption can be a source for the absorption of As in humans. To find a feasible mitigation technique, a field experiment was conducted with broccoli (cv. Green Magic) and cauliflower (cv. Pusa Snowball) in geogenically arsenic-contaminated areas (West Bengal, India) for two consecutive years in a randomized block design replicated seven times with surface irrigation of 20 mm depth, gravity drip and sprinkler irrigation at 1.0 and 0.7 of pan evaporation replenishment. Results revealed that the lowest As accumulation in the edible heads was accomplished by micro-irrigation (0.34 and 0.31 mg kg−1) over the farmer's practice of surface irrigation (0.42 and 0.38 mg kg−1) for broccoli and cauliflower. Micro-irrigation improved the average head yield by 5.26 and 6.53%, weight by 6.37 and 3.06%, and diameter by 1.14 and 1.23% for broccoli and cauliflower respectively and also resulted in substantial water saving to an extent of 37.3%. Further reduction in As stress reduced the activity of antioxidant enzymes like catalase, superoxide dismutase and peroxidase; and reduced the dietary carcinogenic risk like Severity Adjusted Margin of Exposure (SAMOE) from moderate-high to low. Accordingly, drip irrigation without water stress can benefit vegetable growing in the As-contaminated regions based on the competitive advantage.

Effect of Cut-Off Irrigation levels on Production of Teosinte Forage Crop in Clay Soil

The present study was carried out at Sakha Agricultural Research Station (clay soils) middle north of Nile Delta area during summer seasons 2021 and 2022 in randomized complete block design with three replications. The objective of this research was to find out the response of yield, water saving and some water functions for teosinte forage crop to cut-off surface irrigation owing to produce " more per less”. Three irrigation levels were executed; 100% i.e., full irrigation, 90% cut-off irrigation and 80% cut-off irrigation. The mean performances of plant height, fresh and dry forage yields in the two seasons and combined are significantly affected by irrigation levels applied, whereas normal or control treatment with100% irrigation i.e., no cut-off (Trt. A) has the tallest of plant height. On the other hand, the low irrigation level with 80% cut-off (Trt. C) has the shortest plants at the three cuts. Also, traits reduced with the decrease of irrigation water level at the three cuts. Both fresh and dry forage yields are severely decreased when plants irrigated by 80% cut-off. Decreasing the irrigation water level than the commonly controlled of 100% without cut-off (Trt.A) markedly reduced all studied growth characters at the three cuts. The inhibiting effect of the water deficit stress on the studied parameters notably appeared more pronounced under the 80% cut-off than that of 90% .The obtained results may refer to that decreasing the irrigation water lowered the soil moisture content which restricted the mobility of nutrients to plant that would reduce the efficiency of physiological and metabolic processes needed for plant growth. Regarding water relations, irrigation with 90% cut-off resulted in several advantages; almost same yield as obtained under full irrigation, 10% water saving as well as the highest values of crop-water functions of water productivity (WP) and productivity of irrigation water (PIW). The mean values of fresh forage yield of 100% irrigation levels recorded 610 and 685 Kg/strip with compared to 585 and 655kg/strip for 90 %irrigation treatment at first and second cuts, respectively in the first season.

Maize nitrogen uptake, grain nitrogen concentration and root-zone residual nitrate nitrogen response under center pivot, subsurface drip and surface (furrow) irrigation

Maize nitrogen uptake, grain nitrogen concentration and root-zone residual nitrate nitrogen response under center pivot, subsurface drip and surface (furrow) irrigation

N-loaded clinoptilolite under water-saving irrigation mitigates ammonia volatilization while increasing grain yield and water-nitrogen use efficiency

Minimizing ammonia volatilization (AV) in paddy fields can not only reduce nitrogen (N) loss but also prevent environmental pollution. While clinoptilolite has been shown to effectively decrease AV, it is important to note that natural clinoptilolite contains non-desorption active sites that can hinder soil N effectiveness, ultimately leading to decreased N utilization. Therefore, we proposed modifying clinoptilolite with a weakly acidic NH4Cl solution (N-loaded clinoptilolite, NZ) to replenish exogenous N while continuously reducing AV. A lysimeter experiment was conducted under two irrigation regimes (ICF: continuous flooding irrigation; IAWD: alternate wet-dry irrigation) to examine the effect of N-loaded clinoptilolite on soil N, water-N use, AV loss and grain yield over two rice-growing seasons in Northeast China. The results show that AWD significantly reduced AV during the basal fertilization period and the first top-dressing period in 2020 and 2021. Compared with the control (without N-loaded clinoptilolite), N-loaded clinoptilolite at 10 t·ha−1 (NZ10) significantly reduced the total AV by 29% and 33% in the two years, respectively, with the most significant reduction impact (30% and 36%) occurring in the first top-dressing period. NZ10 coupled with AWD regime reduced AV more significantly and compared with conventional management (ICFNZ0), IAWDNZ10 decreased the total amount of AV by 36% and 42% in two years, respectively. N-loaded clinoptilolite also increased the soil NH4+-N and NO3--N content during the tillering and grain-filling stages of rice, which in turn increased the rate of maximum N accumulation, shortened the duration, promoted N accumulation and translocation in rice plants, and finally reduced AV. Additionally, when compared to the control, the utilization of NZ10 under the AWD irrigation regime resulted in an average 29% reduction in irrigation water usage and a yield increase of 5% over two years. Thus, IAWDNZ10 was not only highly productive and water-efficient but also significantly reduced AV, making it an environmentally friendly and effective management model for on-farm practices.

Investigation and Evaluation of Perforated Pipes System Using Plastic Microfilm for Improving Surface Irrigation Performance

Investigation and Evaluation of Perforated Pipes System Using Plastic Microfilm for Improving Surface Irrigation Performance

Yield and Water Productivity of Wheat under Drip-Tape and Surface Irrigation System in East of Isfahan

Yield and Water Productivity of Wheat under Drip-Tape and Surface Irrigation System in East of Isfahan

Strategies for water productivity enhancement in maize—A comprehensive review

AbstractMaize (Zea mays L.) is the third most important cereal crop produced globally after wheat and rice and provides the basic raw materials for starch, oil, protein, alcoholic beverages, food sweeteners and fuel. It is grown on an area of 201.98 Mha worldwide, with an average productivity of 5.75 t ha−1. Maize is mostly grown during the rainy season, but it performs better during the winter season with irrigation and resource conservation techniques. The average productivity of maize during the rainy and winter seasons is 4.3 and 6.2 t ha−1, respectively. The total production is as low as 2.7 Mt in Nepal to 362.78 Mt in the USA. Maize performs better under the furrow and drip irrigation methods, and the range of water requirements is between 425–789 and 351–685 mm, respectively. Plastic and straw mulching has enhanced irrigation water use efficiency up to 34.0–47.2 and 15.3–24.1 kg ha−1 mm−1, respectively. The crop coefficients, Kc values, for maize crops ranges between 0.2 and 1.2. Of the different methods of irrigation, the drip irrigation method enhances the maize yield by 28% and plays a great role in corn yield. This paper discusses various strategies for enhancing global maize yield.

Plot Layout Method of Field Experiment for Wheat with Border Irrigation Based on Soil Water Content Heterogeneity

The objective of this research was to improve the accuracy and representativeness of experimental plot studies by determining the optimum plot area and replication number for winter wheat with border irrigation. Considering the spatial distribution of soil water content, the border effect in relation to crop growth, and the lateral seepage of soil water, we sought to study and optimize the area and specifications of irrigation experiment plots with different levels and replicates. The results show that the experimental irrigation plot consisted of two parts—the core area and the guard area. The most suitable area for the experiment plot core area, with a single level and without replicates, was 60–80 m2. The core experimental area can be arranged with two replicates per 40 m2, with differences in soil moisture content between the treatments reaching more than 15% at the two experiment levels. Each plot comprised two replicates, or if they were 20 m2, then they contained three replicates; when the soil moisture contents differed between 10% and 15%, the area of each replicate plot was 80 m2, comprising two replicates, or 30 m2 with three replicates. When the difference in soil moisture content between the treatments exceeded 15% with the three experimental levels, the area of each plot was 30 m2 and they contained two replicates, or 20 m2 containing three replicates; at differences of 10% to 15%, each replicate plot was 50 m2 containing two replicates, or 30 m2 with three replicates. The experimental plots were rectangular, with irrigation furrows dug lengthwise; therefore, the plots had aspect ratios between 7:1 and 5:1. The width of the buffer area was over 60 cm. The effect of the border on plant height and LAI for winter wheat primarily emerged with one to three rows (20–60 cm) at the jointing stage, while the effect on grain yield and biomass in winter wheat mainly emerged with one to two rows (20–40 cm). The conclusions of this research will inform the development of surface irrigation methods for silt loam in northern Henan, as a reference for optimizing experiment plots employing border irrigation with different soil textures.

Temporal and Spatial Assessment of Soil Salinity Post-Flood Irrigation: A Guide to Optimal Cotton Sowing Timing

Flood irrigation is often applied in the arid regions of Northwest China to facilitate the leaching of salts accumulated in the soil during cotton growth in the previous season. This will, in turn, affect the temporal and spatial patterns of soil salinity, and thus cotton germination. To reveal the salinity of the two soil layers (0–20 cm and 20–60 cm), so as to determine the optimal cotton sowing timing, an electronic ground conductivity meter (EM38-MK2) was employed to measure the soil apparent electrical-conductivity (ECa) on different days: 4 days prior to flood irrigation, and, respectively, 6, 10, 15, 20, and 45 days after flood irrigation. Moreover, geostatistical analysis and block kriging interpolation were employed to analyze the spatial-temporal variations of soil salinity introduced by flood irrigation. Our results indicate that: (1) soil salinity in the two layers on different days can be well inverted from binary first-order equations of ECa at two coils (i.e., ECa1.0 and ECa0.5), demonstrating the feasibility of applying EM38-MK2 to estimate soil salinity in the field; and (2) soil salinity in the 0–20 cm layer significantly decreased during the first 15 days after flood irrigation with the greatest leaching rate of 88.37%, but tended to increase afterwards. However, the salinity in the 20–60 cm layer was persistently high before and after flood irrigation, with merely a brief decrease during the first 10 days after flood irrigation at the highest leaching rate of 40.74%. (3) The optimal semi-variance models illustrate that, after flood irrigation, the sill value (C0 + C) in the 0–20 cm layer decreased sharply, but the 20–60 cm Range of the layer significantly increased, suggesting that flood irrigation not only reduces the spatial variability of surface soil salinity, but also enhances spatial dependence in the 20–60 cm layer. (4) The correlation of the soil salinity between the two soil layers was very poor before flood irrigation, but gradually enhanced during the first 15 days after flood irrigation. Overall, for the study year, the first 15 days after flood irrigation was an optimal timing for cotton sowing when the leaching effects during flood irrigation were most efficient, and overrode the effects of evaporation and microtopography. Although not directly applicable to other years or regions, the electromagnetic induction surveys and spatiotemporal analysis of soil salinity can provide a rapid and viable guide to help determine optimal cotton sowing timing.

Groundwater-surface water interactions in a semi-arid irrigated agricultural valley: A hydrometric and tracer-aided approach

The purpose of this study was to assess hydrological controls (e.g., rainfall, irrigation practices, river discharge, dam operation, evaporation) on surface (SW)- ground water (GW) interactions in an irrigated valley within semi-arid Patagonia Argentina (−65.49 W, −43.29 S). We combined different sampling designs (watershed/sub-watershed scales, longitudinal and monthly samplings) from 2015 to 2019 to investigate the temporal and spatial variation of hydrometrics, electrical conductivity (EC) and stable isotope composition of surface and ground water. Results showed that plant transpiration in the upper basin, evaporation in the middle basin and the reservoir dynamics modified water salinity and left an imprint in stable isotopes. Water tables in the irrigated valley were high (0.5–2 m level from soil surface) and presented higher salinity than river water. Groundwater salinity, temporal variation of water table levels and stable isotopes suggested that groundwater is subjected to evaporation, is recharged from field seepage and, at a lesser extent, from local rainwater. River salinity increased downstream of the irrigated valley during the whole study period (3 years), showing the effects of agriculture and urbanization. EC also responded to the opening and closing of irrigation channels. EC and daily discharge statistical analysis revealed that groundwater recharge the stream below a threshold discharge of 26 m.s−1; with river salinity increasing linearly as daily discharge decrease. This study illustrates the deep modifications that agricultural systems, mainly surface irrigation, produce on semiarid watersheds. Given that SW and GW components are currently not isolated and flow regulation and irrigation practices are playing a critical role in soil quality and river chemistry at low flow conditions, a conjunctive water management strategy must be implemented in order to prevent further land and water quality degradation.