Irrigation Period Research Articles

Multipurpose battery‐assisted solar water pumping system for off‐grid applications: design and development

Providing basic human needs like water and household electricity is a challenging task at remote locations. To support both needs, this study presents the development of a multipurpose battery-assisted solar water pumping system (SWPS). The system consists of only two power electronics converter, viz., bidirectional DC–DC converter, and three-phase voltage source inverter (VSI). The detailed control system is presented, where the DC–DC converter controls the battery power and also ensures the maximum utilisation of stand-alone solar photovoltaic source. In pumping operation, the VSI is operated as a variable frequency motor drive and rotates an induction motor (IM) at the rated power to deliver rated water discharge. In power supply operation, the household electrical load is connected between the mid-point of DC-bus and the star point of an IM winding. The VSI, along with motor inductance, realises the single-phase inverter, which is controlled with synchronous sine pulse-width modulation to deliver single-phase output. The motor does not rotate during this operation and the motor winding acts as a current filter. This multipurpose SWPS assures rated water discharge during the irrigation period and availability of electrical power in the remaining period. A prototype is developed and extensive experiments are performed to investigate system performances.

Lytic Effects of Water on Bladder Cancer Cell Lines – Implications for Clinical Use of Water Irrigation to Reduce Recurrence

Recurrence of bladder cancer (BC) following initial management with transurethral resection of bladder tumour (TURBT) is observed in 15-60% of patients. Intraoperative tumour spillage can be a concern during TURBT, given that it can lead to tumour cell re-implantation and local recurrence. Immediate post-TURBT instillation of chemotherapy is effective at reducing recurrence, but remains underutilised. There is evidence that mechanically washing out free-floating tumour cells with bladder irrigation may be a comparable but less expensive or toxic alternative. Irrigating with sterile water may be more effective compared to iso-osmotic irrigants (such as saline) by virtue of causing additional osmotic cytolysis, but this has not been well characterised. This in vitro study aimed to ascertain the time-course of osmotic effects of water on BC cell lines to guide its meaningful clinical usage. In-vitro studies were conducted on HT1197 and HT1376 BC cell lines, red blood cells, and white blood cells. Each cell line was exposed to either water, 0.9% saline or 1.5% glycine. Cell counts (in triplicate) were performed at 10, 20, and 40 minutes, and then hourly for up to 5 hours using a haemocytometer. Cell viability was determined using Trypan blue. In both BC cell lines, saline and glycine caused respectively ∼50% and 65% reduction in the number of viable cells after a minimum of 1 hour of exposure (p<0.0001 vs time 0). Conversely, the effect of water was rapid, inducing 100% cell lysis in under 20 minutes (p = 0.0001 vs time 0), while saline and glycine had no measurable effect in this timeframe (p = 0.9255 and 0.0662 vs time 0, respectively). For red blood cells and white blood cells, water also precipitated cell lysis within 10 minutes, whilst saline and glycine had minimal effect. These results suggest that water has a rapid osmolytic effect upon BC cells. If confirmed using ex vivo samples from patients, this suggests that a short period of irrigation with water may potentially be effective in reducing BC recurrence.

Improvement in Photosynthetic Rate and Grain Yield in Super-High-Yield Maize (Zea mays L.) by Optimizing Irrigation Interval under Mulch Drip Irrigation

High yield is one of the important goals of crop production, and close planting and optimum irrigation systems are important agronomic practices for increasing maize (Zea mays L.) grain yield. However, little is known about the effect of optimal irrigation interval on the photosynthetic rate (Pn) and dry matter accumulation (DM) of closely planted super-high-yield maize under drip irrigation under mulch. Therefore, the objective of this study was to determine the effects of irrigation interval on the leaf Pn, DM, and grain yield of closely planted super-high-yield maize under mulch drip irrigation in the Xinjiang Uygur Autonomous Region, Northwestern China. A field experiment was conducted using three irrigation intervals in 2016—namely, six days (D6), nine days (D9), and 12 days (D12)—and five irrigation intervals in 2017—namely, three days (D3), six days (D6), nine days (D9), 12 days (D12), and 15 days (D15). The Xianyu 335 high-yield maize hybrid was used in the test; the planting density was set to 12×104 plants ha−1, and an optimal irrigation quota of 540 mm was used. The results showed that during the irrigation period, (1) the soil moisture content (SMC), DM, leaf Pn, and grain yield of treatment D6 were higher than for other irrigation intervals, (2) the leaf Pn and stomatal conductance (GS) of the leaves of treatments D3, D9, D12, and D15 were significantly correlated with the SMC of the 0–40 cm soil layer, and (3) the leaf Pn of treatment D6 was significantly positively correlated with SMC in the 0–60 cm soil layer but not significantly correlated with GS. Irrigation treatment D6 was found to maintain high SMC, provide a water environment favorable to the growth of maize, and increase the leaf Pn and DM, and thereby obtain maize grain yield (20.6–21.0 t ha−1). Therefore, an optimal irrigation interval could be beneficial for adjusting soil moisture, leaf Pn, and DM in order to increase maize grain yield with drip irrigation under mulch.

Irrigation and Precipitation Hydrological Consistency with SMOS, SMAP, ESA-CCI, Copernicus SSM1km, and AMSR-2 Remotely Sensed Soil Moisture Products

Numerous Surface Soil Moisture (SSM) products are available from remote sensing, encompassing different spatial, temporal, and radiometric resolutions and retrieval techniques. Notwithstanding this variety, all products should be coherent with water inputs. In this work, we have cross-compared precipitation and irrigation with different SSM products: Soil Moisture Ocean Salinity (SMOS), Soil Moisture Active Passive (SMAP), European Space Agency (ESA) Climate Change Initiative (ESA-CCI) products, Copernicus SSM1km, and Advanced Microwave Scanning Radiometer 2 (AMSR2). The products have been analyzed over two agricultural sites in Italy (Chiese and Capitanata Irrigation Consortia). A Hydrological Consistency Index (HCI) is proposed as a means to measure the coherency between SSM and precipitation/irrigation. Any time SSM is available, a positive or negative consistency is recorded, according to the rainfall registered since the previous measurement and the increase/decrease of SSM. During the irrigation season, some agreements are labeled as “irrigation-driven”. No SSM dataset stands out for a systematic hydrological coherence with the rainfall. Negative consistencies cluster just below 50% in the non-irrigation period and lose 20–30% in the irrigation period. Hybrid datasets perform better (+15–20%) than single-technology measurements, among which active data provide slightly better results (+5–10%) than passive data.

Simulation soil water–salt dynamics in saline wasteland of Yongji Irrigation Area in Hetao Irrigation District of China

Abstract In order to explore the regional water–salt balance mechanism in Hetao Irrigation District, field experiments were conducted in 2018 and 2019 in the Heji canal study area. The SWAP model was calibrated and validated based on field experiments' observed data. The SWAP model was used to simulate soil water–salt dynamics in saline wasteland after calibration and validation. The results showed that model simulation results of soil water content and soil salt concentration agreed well with the measured values. Soil water content and soil salt concentration changed obviously under the effect of farmland irrigation in the crop growing period. Soil salt was accumulated in saline wasteland. The soil salt accumulation of each soil layer in saline wasteland was 0.164, 0.092, −0.890 and −1.261 mg/cm3, respectively. Soil water content gradually increased and soil salt concentration gradually decreased in the autumn irrigation period. Soil salt was leached in the saline wasteland. The soil salt accumulation of each soil layer in the saline wasteland was −1.011, −1.242, −1.218 and −1.335 mg/cm3, respectively. The saline wasteland became a drainage and salt drainage region for cultivated land. The saline wastelands had an obvious role in adjusting salt balance and maintaining salt dynamic balance in Hetao Irrigation District.

Analysis of spatio-temporal dependence of inflow time series through Bayesian causal modelling

This paper aims to assess fully the spatio-temporal dependence dimensions of inflow across two adjacent and parallel basins and among different time steps through Causality. This is addressed from the perspective of Causal Reasoning, supported by Bayesian modelling, under a novel framework named Bayesian Causal Modelling (BCM). This is applied, through a “concept-proof”, to the Jucar River Basin (the second largest basin of Eastern Spain, characterized by long and severe drought conditions). In this “concept-proof” a double goal is evaluated; first dedicated to a lumped analysis of dependence and second a specific one over dry periods focused on time-horizon of the Jucar basin typical drought (3 years). These challenges comprise the development of two fully connected Bayesian Networks (BNs), one for each challenge populated/trained from historical-inflow records. BNs were designed at a season-scale and consequently, time was upscaled and grouped into Irrigation and Non-Irrigation periods, according to Jucar River Basin Authority operational practices. Results achieved showed that BCM framework satisfactorily captured the spatio-temporal dependencies of systems. Furthermore, BCM is able to answer to some key questions over interdependencies between adjacent and parallel subbasins. Those questions may comprise, the amount of spatial dependences among time series, the temporarily conditionality among subbasins and the spatio-temporal dependence among basins. This provides a relevant insight on the intrinsic spatio-temporal dependence structure of inflow time series in complex basins systems. This approach could be very valuable for water resources planning and management, due to its application power for predicting extreme events (e.g. droughts) as well as improving and optimizing the reservoirs operation rules.

Effects of integration of micro-sprinkler irrigation and nitrogen on growth and development of winter wheat and water and fertilizer use efficiency

Under the same irrigation amount and nitrogen application rate and after the corn stalks being returned to the field in the wheat-corn crop rotation area, we examined the effects of the integrated water and nitrogen mode of micro-sprinkler irrigation on the growth and development and water and fertilizer use efficiency of winter wheat. In 2016-2018, we conducted a two-year field experiment with six types of micro-sprinkler irrigation water and nitrogen integration modes and seven treatments during the growth period, and investigated the population dynamics, dry matter accumulation transfer during the filling period, and nutrient accumulation during the mature period. There were three modes of irrigation, W1(overwintering water + jointing water + grouting water, 600 m3·hm-2 for each), W2(overwintering water + regreening water + jointing water + grouting water, each for 450 m3·hm-2), and W3(600 m3·hm-2 each for overwintering water and jointing water, and 300 m3·hm-2 each for regreening water and grouting water); two modes of nitrogen application, N1(basic nitrogen application 60% + jointing water nitrogen topdressing 40%) and N2 (basic nitrogen application 60% + jointing water nitrogen topdressing 30% + grouting water nitrogen topdressing 10%); with no fertilization under W1 as control (CK). The results showed that: 1) The amount of overwintering water irrigation increased from 450 m3·hm-2to 600 m3·hm-2, which was beneficial to the total number of both stems and panicles in the overwintering period and consequently to yield. Irrigation in the regreening stage increased the total number of stems at the jointing stage, but with limited effect on the number of panicles. Applying more nitrogen at the jointing stage increased the number of stems per plant, but decreased that of panicles. 2) Four times of irrigation (W2 and W3) during the growth period, combined with nitrogen (N2) in the jointing and filling phases, were conducive to the accumulation of dry matter during the filling period, increasing the number of grains per spike and 1000-grain weight, thereby increasing yield. 3) Compared with the three times of irrigation treatment during the growth period, water consumption and absorption of nitrogen, phosphorus and potassium under the four times of irrigation treatment were increased, and water and fertilizer use efficiency was improved. In W2 and W3 under the treatment of four times irrigation, water consumption of N2 during the growth period was lower than N1, absorption of nitrogen, phosphorus, and potassium were higher than N1, and the irrigation and utilization of nitrogen, phosphorus and potassium were significantly improved, of which W3N2 had the best effect. Therefore, W3N2 treatment (sowing winter wheat after returning corn stalks to the field, irrigating four times during the growth period of micro-sprinkler irrigation, increasing the amount of overwintering water and jointing water irrigation to 600 m3·hm-2, combined with jointing water and filling water topdressing nitrogen fertilizer) increased spike number and 1000-grain weight of wheat andincreased yield, with the highest water and fertilizer use efficiency. It was the best water and nitrogen management mode for the integration of micro-sprinkler irrigation and water and fertilizer for winter wheat in southern Shanxi.

Minimal irrigation requirements of Kentucky bluegrass and tall fescue blends in the northern transition zone

AbstractLawns in the cool‐humid region typically consist of mixtures or blends of cool‐season turfgrass species and cultivars. To maintain a desirable aesthetic appearance and maximize seasonal greenness, many lawns receive supplemental irrigation. Turfgrass breeders have developed superior cultivars with reduced water needs, but the exact proportion of these grasses to include in lawn seed blends to reduce irrigation needs has not been well documented. A field study was conducted to determine the irrigation requirements of various blend ratios (0, 25, 50, 75, and 100%, w/w) of drought‐tolerant (DT) and drought‐susceptible (DS) Kentucky bluegrass (Poa pratensis L., KBG) and turf‐type tall fescue [Schedonorus arundinaceus (Schreb.) Durmort., syn. Festuca arundinacea Schreb.; TF] cultivars at two mowing heights (5.1 or 8.9 cm). Supplemental irrigation requirements were determined over a 74‐d deficit irrigation period using a 70% green coverage threshold (GCT70) approach, where 12.7 mm of supplemental irrigation was applied if an individual plot fell below GCT70 using digital image analysis. Total irrigation needs ranged from 66.7 to 176.9 mm, and TF generally required the least irrigation. For KBG, a blend containing ≥75% DT cultivar required the longest time to reach GCT70 (25–33 d), the least irrigation (94–110 mm), and provided the highest overall visual quality. The TF responses were more variable, and the magnitude of differences among cultivar blends was less compared with KBG. These results indicate that where blending of cultivars is desired, the inclusion of cultivars with demonstrated drought tolerance in blends is important for reducing lawn irrigation needs.

Postveraison Deficit Irrigation Effects on Fruit Quality and Yield of "Flame Seedless" Table Grape Cultivated under Greenhouse and Net.

Lack of color in the skin of red table grape varieties is a serious problem in areas of warm climate. This problem is often addressed by the application of ethylene release products such as ethephon. Strict regulation in the use of this product in EU forces European grape producers to look for suitable alternatives. With the aim to increase red skin color, we applied regulated deficit irrigation (RDI) strategies from veraison until harvest on “Flame Seedless” table grape vines cultivated under nets and under a plastic greenhouse in South East Spain, and compared yield and fruit quality with vines fully irrigated under the same net and plastic greenhouses. Our results show a modest improvement in the percentage of commercial clusters with better skin color, probably because the short duration of the deficit irrigation period only caused a slight decrease in soil water content and a mild water stress in RDI vines. Larger differences were observed under the more limiting conditions of the plastic greenhouse for light environment, especially when berry skin color was measured by CIRG (color index of red grape). More noticeable effect of RDI was noted on fruit earliness. Water savings were also remarkable. Negative effects of RDI on berry size or total soluble solid content were not perceived. Our results suggest that RDI is a suitable strategy to save irrigation water without substantial negative effects on yield and berry size. However, the effects on skin color were insufficient in the trial conditions.

Response of shelterbelt transpiration to shallow groundwater in arid areas

Shelterbelts play an important ecological function in arid irrigation land, while competing for water which otherwise supports crop growth. Estimation of shelterbelt water consumption from groundwater is essential to better manage shelterbelts in irrigation districts, but often a challenging task due to its geometry and varying accessibility to groundwater. In the study, sap flow of Populus popularis planted along an irrigation canal was measured during two growing seasons (2016–2017) to investigate its response to varying shallow groundwater. Considering the radial pattern of sap flux density (Js) and measurement azimuthal effect, corrected Js was adopted to better represent transpiration. The results indicate that increased soil moisture and groundwater table during irrigation periods with water flowing in the canal enhance relative Js of shelterbelt by 5.5–25.8% from the non-irrigation intervals. The threshold of groundwater depth (3.6 m) is identified, beyond which transpiration of the seven-year-old shelterbelt becomes very low. Greenbelt transpiration strongly depends on groundwater within the threshold, and can be estimated through an exponential function of the ratio of atmospheric demand and groundwater depth. Besides, with the decrease of reference evapotranspiration from June to September, the sensitivity of shelterbelt transpiration response to groundwater table depth was increased. This study provides necessary information to evaluate farmland shelterbelt transpiration for rational water resource allocation to meet the ecological water requirement in arid areas with shallow groundwater.

GEOLOGICAL STRUCTURE OF SOILS AND RICE YIELD IN THE ILI RIVER BASIN

Rice irrigation systems in Kazakhstan are located on river terraces and levees of the Syr Darya, Ile, and Karatal rivers’ basins. The geological structure and lithological composition of soils in the aeration zone is characterized by a wide variety, differing in soil fertility, mechanical composition, water and physical properties, water availability and salinity. Alluvial-meadow and takyr soils consist of light and heavy loam, sandy loam, and clay [1,2,3]. Melioration errors of the rice irrigation systems, built in the period from 60s to 80s of the last century, can be described by the fact that the Kubanskaya rice sowing map was built on all soils of river terraces and river banks, with the same parameters of irrigation and drainage, with the share of rice 57.5% and 63% [4]. At the rice irrigation systems, where the geological structure and lithological composition of the aeration zone soils correspond to the irrigation and drainage parameters of the Kubanskaya rice sowing map, the soil fertility and ameliorative status of irrigated land has remained high for many decades. The salt content in the 100 cm soil layer is 0.3-0.4%; in the autumn-winter period ground water is at a depth of 2.0-2.5 m, its mineralization is 5-7 g/l. During the rice irrigation period, ground water does not connect with the water of rice paddies, and the filtration of water from rice paddies is permitted and comprises 12 – 17 mm/day. Rice is grown without flow and discharge of water from rice paddies, the irrigation rate is 21,400 m3/ha, and the yield is 5.2 t/ha. At the rice irrigation systems, where the geological structure and lithological composition of the soil in the aeration zone does not correspond to the irrigation and drainage parameters of the Kubanskaya rice sowing map, the land is saline. During the rice irrigation period, the ground water connects with the water on the rice paddies. On these paddies, due to the convective diffusion of salts from the soil and from ground water, water salinity increases and reaches the critical threshold of toxicity of 2.5 g/l [5]. It is necessary to discharge water to reduce the salinity of water on the rice paddies, which is followed by flooding of water from the irrigation channel. The irrigation rate is 23,500 m3/ha, and the yield is 4.7 t/ha.

Agent-based modelling of water balance in a social-ecological system: A multidisciplinary approach for mountain catchments

The European Alps are known as the ‘water towers of Europe’. However, climatic and socioeconomic changes influence both water supply and demand, increasing the need to manage this limited and valuable resource properly to avoid user conflicts and water scarcity. Two major challenges emerge when assessing water scarcity in the Alps: Firstly, mountainous regions are very heterogeneous regarding water availability and demand over space and time, and therefore water scarcity assessments need to be done at low temporal and spatial scales. Secondly, the tight coupling of the natural and the social sphere necessitate an integrative approach considering dynamics and interactions of the social-ecological system. Hence, we applied the agent-based water supply and demand model Aqua.MORE, which is designed for catchment scale and sub-daily temporal resolution, to a case study site in the Italian Alps. In the model, the water supply, the local water managers and water users are represented by interacting model agents. We estimated the water supply by refining the annual runoff data provided by the InVEST water yield model for within-year variations. Local stakeholders contributed to the development of quantitative and spatially-explicit scenarios for land use and tourism evolution. To evaluate water supply and demand dynamics, we assessed six scenarios for the period of 2015 to 2050: three different socio-economic policy pathways, both alone and in combination with a climate change scenario. In all six scenarios, the water demand:supply (D:S) ratio continuously rises from 2015 to 2050.The highest D:S ratio values are prognosed at the beginning of the irrigation period in May. In all scenarios considering climatic changes, the D:S ratio exceeds 20% for several days, indicating potential water scarcity. The simulation results reinforce the importance of analysing water balances at a high temporal resolution and can support management processes and stakeholder dialogues for sustainable watershed management.

Spatiotemporal distributions and mixing dynamics of characteristic contaminants at a large asymmetric confluence in northern China

Previous studies of confluences have mainly concentrated on their hydrodynamic characteristics and morphological dynamics. However, the increasing environmental pollution in rivers has resulted in abrupt variations in water quality at confluences, thus affecting the ecosystems in river networks. Therefore, more attention should be paid to the pollutant distribution and mixing processes at confluences. In this study, several field experiments on pollutant concentrations were conducted at a large asymmetric confluence with a discordant bed and wide-shallow channel in northern China, where a heavily polluted tributary known as the Fen River joins the Yellow River. The results displayed that the heavily polluted tributary seriously affected the water quality at the confluence, especially in the downstream channel near the tributary. The contaminations at the confluence present a relatively strong temporal variability. The organic matter and dissolved oxygen show a similar seasonal variability with each other whereas ammonia nitrogen and total phosphorus are also similar to each other, but they have a different variability from the first group. These pollutants mostly demonstrated the same spatial distribution characteristics, with large horizontal concentration differences at the confluence. The standard deviation of the cross-sectional concentration gradually decreased with the downstream mixing of contaminants. Nonetheless, under conventional hydrological conditions, these contaminants were not completely mixed through a length of 27 river widths. Compared with a concordant bed, this discordant confluence exhibited a relatively fast mixing rate. The key factor affecting the mixing process at the confluence was the discharge ratio. Exceptionally, during the irrigation period (March–April), owing to the extremely low discharge of the tributary, the main stream flowed backward into the tributary, which enhanced the mixing motion to constitute an approximately full mixing regime at the mouth of the tributary. These results are of great importance in understanding the degree of contamination, spatiotemporal distribution and mixing dynamics of characteristic pollutants at complex river confluences.

Study of the geostatistical grid maths operation method of quantifying water movement in soil layers of a cotton field*

AbstractThe precise quantification of water movement in different field soil layers is important for variable‐rate irrigation and fertilization. To this end, a field experiment based on a geostatistical approach was conducted in southern Anyang, Henan, China, to examine soil water movement in a cotton field with drip irrigation by measuring the soil water content (SWC) data on a regular 100 × 80 cm grid. The result shows that the temporal and spatial variation of soil moisture decreased with the increase of soil depth at different points, and apparent spatial heterogeneity was observed under different soil conditions through a semivariogram analysis. The variation of soil moisture at different soil profiles was affected by the cotton plants and drip lines in non‐irrigation and irrigation periods respectively. The level of the change at 20 cm was more than 70 cm in the horizontal direction in the two periods, however the degree of change at 40 cm in the irrigation period was more than 70 cm in the vertical direction, while contrary results were shown in the non‐irrigation period. Moreover, the results indicated that the trapezoidal rule could be applied to quantify the volume of water movement precisely.

Hydrogeological conceptual model of an irrigated agricultural area, Buenos Aires Province, Argentina

In Argentina, the complementary irrigation has increased in most agricultural regions, where it is necessary to minimize possible negative impacts on the quantity and quality of groundwater. Numerical modeling techniques are used to obtain projections of the aquifer dynamics, for which a conceptual model is needed that provides the input data in the numerical simulations.A hydrogeological conceptual model for a rural area of Buenos Aires Province (Argentina), where complementary irrigation has caused significant depletion of groundwater levels during the irrigation season, has been developed. It was based on available geophysical and hydrogeological information and measurements of piezometric levels and hydraulic parameters of the aquifer together with the geochemical analysis of groundwater. This model was imported to a numerical model and the hydrogeological parameters were adjusted by the calibration with static piezometric levels measured in the wells. The conceptual model was validated satisfactorily using a fitting criterion to reach a value of root mean square error less than 5%. Different simulations of the probable drawdowns of the levels due to pumping were performed in the study area.The main hydrogeological unit is semi-confined, mostly comprising of a multilayer unit with good quality of water. Its minimum and maximum thickness was 60 and 240 m, respectively. The groundwater flows northwards from the hilly area to the plains. The recharge was 4.6 mm.year−1, representing 5% of annual precipitation. Dynamic simulations show that the aquifer gets dried, which questions its sustainability. The alternating condition of the source or drain of the streams depends on the irrigation period or the dry season, respectively. Great drawdowns of piezometric levels in some areas might be the cause of changes in water classification. These results lead to the need of planning the use of groundwater as a complement to agricultural activity, considering sustainable employment of the resource.

Remotely-Sensed Surface Temperature and Vegetation Status for the Assessment of Decadal Change in the Irrigated Land Cover of North-Central Victoria, Australia

Monitoring of irrigated land cover is important for both resource managers and farmers. An operational approach is presented to use the satellite-derived surface temperature and vegetation cover in order to distinguish between irrigated and non-irrigated land. Using an iterative thresholding procedure to minimize within-class variance, the bilevel segmentation of surface temperature and vegetation cover was achieved for each irrigation period (Spring, Summer and Autumn). The three periodic profiles were used to define irrigation land covers from 2008–2009 to 2018–2019 in a key agricultural region of Australia. The overall accuracy of identifying farms with irrigated land cover amounted to 95.7%. Total irrigated land cover was the lowest (approximately 200,000 ha) in the 2008–2009 crop year which increased more than three-fold in 2012–2013, followed by a gradual decline in the following years. Satellite images from Landsat series (L-5, L-7 and L-8), Sentinel-2 and ASTER were found suitable for land cover classification, which is scalable from farm to regional levels. For this reason, the results are desirable for a range of stakeholders.

SURGICAL TREATMENT OF THE ODONTOGENIC KERATOCYST: A CASE REPORT

Odontogenic keratocyst (OKC) is a benign cyst originated from dental blade remnants, but has aggressive biological behavior with great recurrence potential. This report describes an OKC occurrence in a 15-year-old melanoderma male patient that reported a swelling in the mandible posterior region. The computed tomography revealed a well delimited and slightly corticalized hypodense image involving the mandible posterior teeth. It was performed a punch biopsy and the histopathological analysis evidenced fibrous cystic capsule with discrete mononuclear inflammatory infiltrate, hemorrhagic areas, small mineralized tissue fragments compatible with bone tissue and no signs of malignancy, pointing OKC diagnosis. After the lesion marsupialization and a periodic saline solution irrigation, the enucleation treatment was realized with a large safety margin. After 10 months, a recurrence was observed and the same surgical procedure was performed with a shorter period of saline solution irrigation. He is under follow-up for 2 years with no signs of recurrence.

Effects of soil heterogeneity on subsurface water movement in agricultural fields: A numerical study

This study aims to numerically examine the effects of soil heterogeneity on subsurface water movement in agricultural fields under wheat (Triticum aestivum L.) and rice (Oryza sativa L.) crop covers. The 3-D Richards equation that accounts for root water uptake was coupled with a random field generation method to produce realizations of soil hydraulic properties, and the effects of soil heterogeneity were analyzed under realistic atmospheric boundary conditions. Four soil types and three different soil heterogeneity levels were considered to investigate the response of soil heterogeneity on soil water dynamics. It was observed that the effect of soil heterogeneity varies across soil types and its effect was more pronounced in silty clay loam soils. Further, an increase in soil heterogeneity level can increase or decrease the mean soil moisture, hydraulic conductivity, and flow velocity based on land cover, upper boundary condition, and atmospheric demand, and its effect was higher during irrigation periods. A maximum difference of 30% in soil moisture values was observed near the surface soil layers due to an increase in soil heterogeneity on irrigation days. The mean soil moisture content under rice crop cover was always lower than that of wheat crop cover due to higher atmospheric demand in the former. Soil layering effect on soil moisture dynamics, which is related to capillary and hydraulic barrier formation, was found to depend on the layering configuration, available soil moisture, and land cover. The numerical experiments provided useful insights into the complex soil moisture dynamics in agricultural fields.

MAPPING IRRIGATED AREAS USING RANDOM FOREST BASED ON GF-1 MULTI-SPECTRAL DATA

Abstract. The irrigation districts need high-resolution spatial distribution information of irrigated fields to manage irrigation water effectively and achieve sustainable water resources management, especially for fragmented croplands such as China. However, most irrigated area mapping methods by remote sensing are based on MODIS time series with a relatively low resolution of 250–1000 m. To fill this gap, this study attempted to use pixel-based random forest to map irrigated areas based on two multi-spectral images from GF-1 satellite with a resolution of 16 m in an irrigated district of China, during the winter-spring irrigation period of 2018. Accuracy of the retrieved 16-m map was assessed by accuracy error matrix using 210 ground-truth samples. The result had an overall accuracy of 93.33% with a Kappa Coefficient of 0.9164. The 16-m resulting map shows that the area of irrigated wheat, rain-fed wheat, irrigated fruit tree, and fallow croplands in the study area were 52066.48 ha, 12932.33 ha, 18104.32 ha, and 4641.25 ha respectively, accounting for 52.57%, 13.06%, 18.28% and 4.69% of the total study area, which are basically consistent with those obtained from field investigations. Compared with SVM, the random forest results are more accurate with fewer misclassifications. The pixel-based random forest for irrigated area mapping at high resolution can obtain more refined spatial distribution of irrigated areas than low-resolution images, which is suitable for fragmented croplands. Besides, this method can effectively distinguish irrigated crops from rain-fed crops, proving the classification ability of random forest in high-resolution irrigation area mapping only by two images.

Introducing Life Cycle Assessment in Costs and Benefits Analysis of Vegetation Management in Drainage Canals of Lowland Agricultural Landscapes

Nitrate pollution remains an unsolved issue worldwide, causing serious effects on water quality and eutrophication of freshwater and brackish water environments. Its economic costs are still underestimated. To reduce nitrogen excess, constructed wetlands are usually recognized as a solution but, in recent years, interest has been raised in the role of ditches and canals in nitrogen removal. In this study, we investigated the environmental and economical sustainability of nitrogen removal capacity, using as a model study a lowland agricultural sub-basin of the Po River (Northern Italy), where the role of aquatic vegetation and related microbial processes on the mitigation of nitrate pollution has been extensively studied. Based on the Life Cycle Assessment (LCA) approach and costs and benefits analysis (CBA), the effectiveness of two different scenarios of vegetation management, which differ for the timing of mowing, have been compared concerning the nitrogen removal via denitrification and other terms of environmental sustainability. The results highlighted that postponing the mowing to the end of the vegetative season would contribute to buffering up to 90% of the nitrogen load conveyed by the canal network during the irrigation period and would reduce by an order of magnitude the costs of eutrophication potential.