Irrigation Period Research Articles

Irrigation of soil with reclaimed wastewater acts as a buffer of microbial taxonomic and functional biodiversity

The usage of reclaimed wastewater (RWW) for irrigation of agricultural soils is increasingly being acknowledged for reducing water consumption by promoting reuse of treated wastewater, and for the delivery of extant nutrients in the soil. The downside is that RWW may be a vector for contamination of soils with contaminants of emerging concern (CECs), if left uncontrolled. Its usage is anticipated to alter the soil properties, consequently also the soil microbial community. In the present study, soil microcosms were set to monitor how short periods (up to fourteen days) of RWW irrigation influence the soil ecosystem, namely its physicochemical properties, functioning, and colonising microbiota (differentiating fungi from bacteria). Two scenarios were studied: clean soil and soil contaminated (spiked) with 9 CECs, at conditions that limit any abiotic decay processes, monitoring along time fluctuations in the taxonomic and functional microbiota diversity. As shortly as fourteen days, the irrigation of either soil with RWW did not significantly (p > 0.05) alter its physicochemical properties and scarcely impacted the bioremediation processes of the CECs that showed decay levels ranging from 24% to 100%. Bacillus spp. dominance was enhanced along time in all the soil microcosms (reaching over 70% of the total abundance on the 7th day) but the RWW help to preserve, to some extent, high bacterial diversity. Besides, irrigation with RWW acted as a buffer of the soil mycobiota, limiting alterations in its composition caused either along time (to a minor degree) or due to contamination with CECs (to a great degree). This includes limiting the rise of Rhizopus sp. relative abundance. Collectively, our data support the utility of short-term periods of RWW irrigation for preserving the soil microbial diversity and functioning, especially when fungi are considered.

Physiological response of flag leaf and yield formation of winter wheat under different spring restrictive irrigation regimes in the Haihe Plain, China

In order to identify the optimum period of spring water-restrictive irrigation for winter wheat (Triticum aestivum L.) in the Haihe Plain, China and elucidate its effects on flag leaf senescence and yield formation, field experiments were conducted at the Xinji Experimental Station of Hebei Agricultural University from 2016 to 2019 by using different irrigation regimes in spring, including the conventional regime involving two irrigation periods (control (CK), the 3-leaf unfolding stage and the anthesis stage) and a series of single, restrictive irrigation regimes (SRI) comprising irrigation at the 3-leaf unfolding stage (3LI), 4LI, 5LI, and 6LI. There are five major findings: (1) The senescence (determined by the green leaf area, GLA) in the 4LI treatment occurred moderately earlier than that in CK, showed no significant difference with that in 5LI and 6LI, and occurred significantly later than that in 3LI. (2) Compared with other SRI treatments, the GLA value and photosynthetic rate in 4LI were 14.82 and 20.1% higher, respectively. Microstructural analysis of flag leaf also revealed that the mesophyll cells and chloroplasts were irregularly arranged under drought stress in 3LI and 6LI; however, drought stress had minimal negative effects on the microstructure in 4LI and 5LI. (3) Postponed irrigation in spring could significantly increase superoxide dismutase (SOD) and catalase (CAT) activities in the early stage of grain filling; however, these activities would subsequently decrease. Among the four SRI treatments, the overall enzyme activities were the highest in 4LI, and the combined malondialdehyde (MDA) content in flag leaves in 4LI and 5LI was 14.5% lower on average than that in 3LI and 6LI. (4) The soluble sugar (SS) and proline (Pro) contents in 4LI were the highest among the four SRI treatments; however, they were lower than those in CK. The abscisic acid (ABA) hormone content in 4LI and 5LI was lower than that in 3LI and 6LI, respectively, suggesting a smaller drought stress effect in 4LI and 5LI. (5) In two growing seasons, there was a larger number of spikes per unit area in 4LI (i.e., 13.4% higher than that in 5LI and 6LI) and the 1 000-grain weight in 4LI was the highest among the four SRI treatments (i.e., 6.0% higher than that in the other three SRI treatments). Therefore, a single restrictive irrigation regime at the 4-leaf unfolding stage is recommended to be effective in slowing down the senescence process of flag leaves and achieving high yield.

Use of the stable oxygen isotope method to evaluate the difference in water consumption and utilization strategy between alfalfa and maize fields in an arid shallow groundwater area

Returning farmland to grasslands (RFG)to restore soil fertility and prevent land degradation in overused agricultural lands is an important measure. However, the hydrological processes, water consumption and utilization in field systems are undoubtedly changed in shallow groundwater areas owing to RFG. Experiments in the Hetao irrigation district, Inner Mongolia, China, during 2017 (2-yr for alfalfa) and 2018 (3-yr for alfalfa) were conducted to evaluate the difference in soil water distribution, percolation, groundwater recharge, water consumption and water productivity between alfalfa (Medicago sativa L.) and maize (Zea mays L.) fields. The stable oxygen isotope method was used to reveal a strategy to utilize different water sources for alfalfa and maize in an arid shallow groundwater area. Compared with maize, the increase in water consumption by alfalfa increased the soil water consumption of the 0–100 cm soil layer and the groundwater recharge, which led to an increase of 9.44 mm and 65.32 mm, respectively. However, the leakage below 100 cm layer decreased by 44.91% compared with those of the maize field. The yield and WPc of alfalfa were 29.27% and 6.28% greater than that of maize in 2018, respectively. Percentages of 75.43%, 18.73% and 5.84% of irrigation water, groundwater and precipitation were taken up by alfalfa during the irrigation period, respectively, while it was 81.27%, 12.90% and 5.83% in the maize field, respectively. After irrigation, the crops primarily absorbed water from upper soil layer (0–40 cm), comprising 72.93% (alfalfa) and 69.8% (maize). However, more water from the deeper layers was used by alfalfa before irrigation, and the average contribution of 40–100 cm soil layer was 63.0%, an increase of 11.2% compared with maize. In addition, even though maize absorbed water by roots that could reach a soil depth of 80 cm, it primarily drew water from the 40–60 cm soil layer.

Monitoring of Emerging Water Stress Situations by Thermal and Vegetation Indices in Different Almond Cultivars

In recent years, the area dedicated to modern irrigated almond plantations has increased significantly in Spain. However, the legal irrigation allocations are lower than the maximum water requirements of the crop in most cases. Therefore, almond growers are forced to implement regulated deficit irrigation strategies on their farms, applying water stress in certain resistant phenological periods and avoiding it in sensitive periods. Given the need to monitor the water status of the crop, especially in the most sensitive periods to water stress, the objective of this work was to evaluate the sensitivity of two UAV-based crop water status indicators to detect early water stress conditions in four almond cultivars. The field trial was conducted during 2020 in an experimental almond orchard, where two irrigation strategies were established: full irrigation (FI), which received 100% of irrigation requirements (IR), and regulated deficit irrigation (RDI), which received 70% of IR during the whole irrigation period except during the kernel-filling stage when received 40% IR. The UAV flights were performed on four selected dates of the irrigation season. The Crop Water Status Index (CWSI) and the Normalized Difference Vegetation Index (NDVI) were derived from thermal and multispectral images, respectively, and compared to classical water status indicators, i.e., stem water potential (Ψstem), stomatal conductance (gs), and photosynthetic rate (AN). Of the four flights performed, three corresponded to mild water stress conditions and a single flight was performed under moderate water stress conditions. Under mild water stress, CWSI was not able to capture the differences between FI and RDI trees that were observed with Ψstem. Under moderate stress conditions, CWSI was sensitive to the water deficit reached in the trees and showed significant differences among both irrigation treatments. No differences were observed in the CWSI and NVDI response to water stress among cultivars. Although NDVI and CWSI were sensitive to water stress, the low signal intensity observed in NDVI makes this index less robust than CWSI to monitor crop water stress. It can be concluded that UAV-based CWSI measurements are reliable to monitor almond water status, although for early (mild) levels of water stress, Ψstem seems to be the preferred option.

Crop pan coefficients for potato (Solanum tuberosum L.) according to the irrigation program created by monitoring soil moisture

This study was carried out with the aim of determining the appropriate plant (Kc) and Pan (Kp) coefficients for Class A Pan by using the irrigation program that was monitored by soil moisture in the potato (Solanum tuberosum L.). Irrigation treatments consisted of one irrigation interval (5 days) and five different levels (I100, I85, I70, I55, I40) of soil water deficit measured before irrigations. Before thematic irrigations, all treatments were irrigated up to field capacity of the soil water content in 0–0.6 m depth. The results showed that as the water stress increased the yield and quality decreased in potatoes. Especially when more than 30% water deficiency was applied, a significant decrease in efficiency and quality was observed. The highest tuber yield per plant was obtained with 1.2498 kg in the first year and 1.2166 kg in the second year on I100 treatment (p < 0.001). In the study, while the Kc values in the irrigation periods for the potato plant were 0.81 in the first year and 0.79 in the second year, Kp was determined as 1.23 and 1.20 for full irrigation (I100) treatment, respectively.

An Operational Framework for Mapping Irrigated Areas at Plot Scale Using Sentinel-1 and Sentinel-2 Data

In this study, we present an operational methodology for mapping irrigated areas at plot scale, which overcomes the limitation of terrain data availability, using Sentinel-1 (S1) C-band SAR (synthetic-aperture radar) and Sentinel-2 (S2) optical time series. The method was performed over a study site located near Orléans city of north-central France for four years (2017 until 2020). First, training data of irrigated and non-irrigated plots were selected using predefined selection criteria to obtain sufficient samples of irrigated and non-irrigated plots each year. The training data selection criteria is based on two irrigation metrics; the first one is a SAR-based metric derived from the S1 time series and the second is an optical-based metric derived from the NDVI (normalized difference vegetation index) time series of the S2 data. Using the newly developed irrigation event detection model (IEDM) applied for all S1 time series in VV (Vertical-Vertical) and VH (Vertical-Horizontal) polarizations, an irrigation weight metric was calculated for each plot. Using the NDVI time series, the maximum NDVI value achieved in the crop cycle was considered as a second selection metric. By fixing threshold values for both metrics, a dataset of irrigated and non-irrigated samples was constructed each year. Later, a random forest classifier (RF) was built for each year in order to map the summer agricultural plots into irrigated/non-irrigated. The irrigation classification model uses the S1 and NDVI time series calculated over the selected training plots. Finally, the proposed irrigation classifier was validated using real in situ data collected each year. The results show that, using the proposed classification procedure, the overall accuracy for the irrigation classification reaches 84.3%, 93.0%, 81.8%, and 72.8% for the years 2020, 2019, 2018, and 2017, respectively. The comparison between our proposed classification approach and the RF classifier built directly from in situ data showed that our approach reaches an accuracy nearly similar to that obtained using in situ RF classifiers with a difference in overall accuracy not exceeding 6.2%. The analysis of the obtained classification accuracies of the proposed method with precipitation data revealed that years with higher rainfall amounts during the summer crop-growing season (irrigation period) had lower overall accuracy (72.8% for 2017) whereas years encountering a drier summer had very good accuracy (93.0% for 2019).

Ensuring Agricultural Sustainability through Remote Sensing in the Era of Agriculture 5.0

Timely and reliable information about crop management, production, and yield is considered of great utility by stakeholders (e.g., national and international authorities, farmers, commercial units, etc.) to ensure food safety and security. By 2050, according to Food and Agriculture Organization (FAO) estimates, around 70% more production of agricultural products will be needed to fulfil the demands of the world population. Likewise, to meet the Sustainable Development Goals (SDGs), especially the second goal of “zero hunger”, potential technologies like remote sensing (RS) need to be efficiently integrated into agriculture. The application of RS is indispensable today for a highly productive and sustainable agriculture. Therefore, the present study draws a general overview of RS technology with a special focus on the principal platforms of this technology, i.e., satellites and remotely piloted aircrafts (RPAs), and the sensors used, in relation to the 5th industrial revolution. Nevertheless, since 1957, RS technology has found applications, through the use of satellite imagery, in agriculture, which was later enriched by the incorporation of remotely piloted aircrafts (RPAs), which is further pushing the boundaries of proficiency through the upgrading of sensors capable of higher spectral, spatial, and temporal resolutions. More prominently, wireless sensor technologies (WST) have streamlined real time information acquisition and programming for respective measures. Improved algorithms and sensors can, not only add significant value to crop data acquisition, but can also devise simulations on yield, harvesting and irrigation periods, metrological data, etc., by making use of cloud computing. The RS technology generates huge sets of data that necessitate the incorporation of artificial intelligence (AI) and big data to extract useful products, thereby augmenting the adeptness and efficiency of agriculture to ensure its sustainability. These technologies have made the orientation of current research towards the estimation of plant physiological traits rather than the structural parameters possible. Futuristic approaches for benefiting from these cutting-edge technologies are discussed in this study. This study can be helpful for researchers, academics, and young students aspiring to play a role in the achievement of sustainable agriculture.

Valorizing the reuse of treated municipal wastewater for Paulownia seedlings cultivation by application of Moringa waste

A field experiment was conducted to study the effect of treated municipal wastewater and adding defatted seeds of Moringa oleifera to the soil with different levels compared to tap water on the vegetative growth and chemical composition of Paulownia hybrid seedlings as well as soil chemical properties. This experiment was carried out in the experimental area of the National Research Centre, Cairo, Egypt from March to December 2019 and 2020 for three irrigation periods (3, 6 and 9 months). The use of treated municipal wastewater individually or in combination with defatted seeds of Moringa oleifera significantly increased all the studied growth parameters comparing to tap water (the control) in all growth intervals. The treatment of treated municipal wastewater with 10 g of defatted seeds of Moringa oleifera was the best than other treatments in improving the most growth parameters. Maximal accumulation of heavy metals occurred in the roots followed by leaf and stem, respectively. A notable increase in antioxidant enzyme activity was noticed in Paulownia seedlings that were treated by treated municipal wastewater alone or with using 20 gm of defatted seeds of Moringa oleifera. The trees of Paulownia were found to be a promising species for trace metal tolerance in polluted soils and using treated municipal wastewater for irrigation. Remediation of soil with defatted seeds of Moringa oleifera had promotion effects on reducing the uptake of metal and decreasing its availability

Effect of root canal irrigant (sodium hypochlorite & saline) delivery at different temperatures and durations on pre-load and cyclic-loading surface-strain of anatomically different premolars

AimTo evaluate the effect of NaOCl (5%) and saline (control) irrigant delivery at different temperatures and durations on pre-load and cyclic-loading tooth-surface-strain (TSS) on anatomically different premolars. MethodologySingle-rooted premolars (n = 36), root-canal-prepared in standard manner, were randomly allocated to six irrigation groups: (A1) NaOCl-21 °C; (A2) NaOCl-60 °C; (A3) saline-21 °C then NaOCl-21 °C; (A4) saline-60 °C then NaOCl-21 °C; (A5) saline-21 °C then NaOCl-60 °C; (A6) saline-60 °C then NaOCl-60 °C. A1-2 received nine 10-min irrigation periods (IP) with NaOCl; A3-6 received nine 10-min IP with saline, followed by 9 IP with NaOCl at different temperature combinations. Premolars (n = 56) with single, fused or double roots prepared by standard protocol, were stratified and randomly allocated to: (B1) saline-21 °C; (B2) saline-80 °C; (B3) NaOCl-21 °C; (B4) NaOCl-80 °C. TSS (μє) was recorded pre-irrigation, post-irrigation and pre-load for each IP and during cyclic loading 2 min after each IP, over 30–274 min, using strain-gauges. Generalised linear mixed models were used for analysis. ResultsBaseline TSS in double-rooted premolars was significantly (p=0.001) lower than in single/fused-rooted-premolars; and affected by mesial-wall-thickness (p=0.005). There was significant increase in loading-TSS (μє) after NaOCl-21 °C irrigation (p=0.01) but decrease after NaOCl-60 °C irrigation (p=0.001). TSS also increased significantly (p = 0.005) after Saline-80 °C irrigation. Pre-load “strain-shift” was noted only upon first saline delivery but every-time with NaOCl. Strain-shift negatively influenced loading-TSS after saline or NaOCl irrigation (A3-6) but was only significant for saline-21 °C. ConclusionsTooth anatomy significantly affected its strain characteristics, exhibiting limits within which strain changes occurred. Intra-canal introduction of saline or NaOCl caused non-random strain shifts without loading. Irrigation with NaOCl-21 °C increased loading tooth strain, as did saline-80 °C or NaOCl-80 °C but NaOCl-60 °C decreased it. A “chain-link” model was proposed to explain the findings and tooth biomechanics.

The Impact of Biological Inoculation on Zea Mays L. growth, Protein Content, and Iron Availability Under Different Levels of Water Stress

This study aims to investigate the effect of biological inoculation with Azotobacter chrococcum and Glomus mosseae on the growth and yield of Zea mays L., the variety of Baghdad 3 under different levels of water stress. A field experiment was carried out in the fall season of 2020 in a private farm in the Diwaniyah Governorate-Afak district. According to the Randomized Complete Block Design R.C.B.D, the experiment was designed with three replications, and the treatment was distributed randomly. Three levels of irrigation were used in the experiment (I4 irrigation every four days, I7 irrigation every seven days, I10 irrigation every ten days) and the levels of inoculation (B1 inoculation with A-chrococcum and B0 not inoculating with bacteria) and ( F1 inoculating with G-mosseae and F0 non-inoculation) and ( B1F1 interaction between fungus and bacteria). The means were compared using the L.S.D. Test at a 5% significance level. The results present that the treatments inoculated with fungi or bacteria or both, and for a seven-day irrigation period, significantly increased the values ​​of the traits (plant height, dry weight of the vegetative part, length of corn cob, protein percentage, soil content of available iron during the flowering and end of season periods). They had the highest values ​​ 358, 85.71, 25.63, 12.23, 0.5423, and 0.4873 cm plant-1, respectively, compared to the treatments (control + irrigation every ten days) as they resulted in 165, 32.87, 9.07, 6.75, 0.3133, and 0.2823 cm plant-1, respectively.

Predicting BOD under Various Hydrological Conditions in the Dongjin River Basin Using Physics-Based and Data-Driven Models

The water quality of the Dongjin River deteriorates during the irrigation period because the supply of river maintenance water to the main river is cut off by the mass intake of agricultural weirs located in the midstream regions. A physics-based model and a data-driven model were used to predict the water quality in the Dongjin River under various hydrological conditions. The Hydrological Simulation Program–Fortran (HSPF), which is a physics-based model, was constructed to simulate the biological oxygen demand (BOD) in the Dongjin River Basin. A Gamma Test was used to derive the optimal combinations of the observed variables, including external water inflow, water intake, rainfall, and flow rate, for irrigation and non-irrigation periods. A data-driven adaptive neuro-fuzzy inference system (ANFIS) model was then built using these results. The ANFIS model built in this study was capable of predicting the BOD from the observed hydrological data in the irrigation and non-irrigation periods, without running the physics-based model. The predicted results have high confidence levels when compared with the observed data. Thus, the proposed method can be used for the reliable and rapid prediction of water quality using only monitoring data as input.

Rice paddy irrigation seasonally impacts stream benthic macroinvertebrate diversity at the catchment level

AbstractAgriculture is one of the most critical anthropogenic disturbances to freshwater ecosystems globally. In monsoon Asia, rice paddies provide habitats for aquatic species, but how their associated irrigation systems can affect downstream ecosystems is poorly understood. Here, we used structural equation modeling (SEM) to estimate seasonal variations in benthic macroinvertebrate diversity and environments and quantified indirect effects of land use, especially of rice paddy areas, on benthic macroinvertebrate diversity through local environmental alteration. Our study site was the Yasu River tributary of Lake Biwa, Japan, and we performed our investigation during both irrigation and nonirrigation periods, representing different seasons. Seasonal variations in physical and chemical variables and diversity were observed. Seasonal particulate phosphorus concentrations to a large extent determined the abundance and community composition of benthic macroinvertebrates. SEM revealed that the proportions of forest, urban, and rice paddy areas in the catchment had significant indirect effects on biodiversity indices of local benthic macroinvertebrate communities. The proportion of forest area had robust negative effects on water temperature, but the overall indirect effects on the macroinvertebrate diversity contrasted between the two seasonal periods. The proportion of rice paddy area had a strongly negative indirect effect on the diversity through increased particulate phosphorous loading during the irrigation period, while the proportion of urban area had a significantly negative indirect effect during the nonirrigation period only. The seasonal negative impacts of rice paddy irrigation on benthic macroinvertebrate communities were possibly due to siltation arising from rice paddy soils. Our results have implications for environmental restoration and biodiversity conservation in catchment management.

Monitoring of Irrigation Area in Chuanhang Irrigation Area Based on MODIS Daily Surface Temperature Range

Monitoring and analysis of irrigated area is of great significance to evaluate irrigation benefit, agricultural drought situation and regional water resources utilization. This article selects MODIS surface temperature products from 2016 to 2020. Using the method of daily difference in surface temperature, eliminating the influence of precipitation, realizing remote sensing monitoring of irrigation intensity and spatial distribution of irrigation area. The results showed that the average number of irrigation times in five years was in the range of 6-8. Due to factors such as rainfall during the irrigation period, the overall irrigation frequency from 2016 to 2018 is less than the overall irrigation frequency in 2019 and 2020. On June 11, 2018, remote sensing images detected irrigation areas of Buzi Town, Longhe Town, Yangbei Town and Chenji Town, which were consistent with the data of irrigation areas.

Effect of amino acid proline on some growth characteristics of cowpea which exposed to drought stress

The study was conducted in Al-Youssoufia region which located in North West of Baghdad city during the growing season of 2018-2019. The experiment was aimed to demonstrate the optimum concentration of amino acid proline that reduce the effect of drought stress. By using three time for irrigation (4, 8, 12) day and four concentrations of proline (0, 20, 40, 60) mg. L-1 and their interaction on some growth characteristics: Root length, dry weight, nitrogen, phosphorous and potassium content, carbohydrate percentage and peroxidase activity in vegetative part. Data were statistically analysed to find out the least significant difference (LSD) between treatments at 0.05 level. The results indicated the increase of proline concentration from (0 to 60) mg.L-1 caused significant decrease in the average of growth characteristics and peroxidase activity unite.mg.proline-1 with increase in the average of irrigation periods under drought stress.

Increasing the Productivity and Efficiency of Water Use by Reserving Water

One use of technology in agriculture involves setting up a reserving sheet for subsurface moisture under the root zone of wheat crops, which is symbolized by SWRT, to conserve the water in the root zone. This reduces the field water losses by raising the efficiency of water use (WUE) and economical water productivity (EWP). For this study, an SWRT membrane sheet was put under the root zone of wheat crops throughout the growing season, from the winter of November 2019 to the end of the season in April 2020, in a free field. The study was conducted on a private farm located in the province of Babylon in Sadat Al-Hindya Town, which is approximately 70 km from the capital (Baghdad). Surface irrigation was utilized for the irrigation of the wheat crops. Two methods were used: method A1 utilized the SWRT sheet and method A2 was conducted without the SWRT sheet. The irrigation water supply, irrigation period, and soil water content before and after irrigation were computed and recorded every day for the A1 and A2 methods. The values of wheat crop production (yield), water use efficiency, and economical water productivity from the two plots were computed and compared. The results obtained for water use efficiency for the two methods, A1 and A2, were 0.51 and 0.47 kg/m3, respectively. The increment in yield of plot A1 compared with plot A2 was 6.45%. The increment in WUE of plot A1 compared with plot A2 was 8.55%. In addition, the WP of the wheat crop for plots A1 and A2 were 144.44 and 119.16 ID/m3, respectively, while the increment in WP of plot A1 compared with plot A2 was 21.21%. The findings show that the SWRT method prevents the environmental effects of pesticide and fertilizers that enter the groundwater and pollute it. This technology assists in saving water and plant nutrients, and prevents pollution of the groundwater from pesticides and excess fertiliser.

Radish cultivation with hydrogel doses combined with different water slides in drip irrigation system

Radish yield and quality are factors influenced by water stress that may occur during periods of drought or irrigation handled inappropriately, interfering negatively in plants development, producing radishes of inferior quality and in lesser quantity. In addition to irrigation, which makes water available in the system, it is important to maintain it with the use of water-retaining products such as hydrogel. The aim of this work was to evaluate radish yield, submitted to three different hydrogel doses combined with two water slides. The experimental design was in factorial scheme 3 x 2, with three water slides (50%, 75% and 100% Eto – reference evapotranspiration estimate) and two hydrogel doses (40 and 60 g m-2) with four replicates. Number of leaves, horizontal and vertical root diameter (mm), total and shoot length (cm), fresh mass of root and shoot (g), dry mass of shoot and root (g) and yield (t ha-1) were evaluated. The best results, regarding radish production and development, were obtained when using 50% of Eto with 60 g m-2 of hydrogel in combination. Thus, radish cultivation in oxisoil was influenced by the use of hydrogel, which provided a more efficient water level use.

Simulation study on the migration of F− in soil around Chagan Lake, China

Chagan Lake is located in the high-fluorine area of western Jilin, with high fluoride content in surface water, soil, and groundwater around it. Due to its unique topography and hydrogeological conditions, Chagan Lake collects surrounding water and is closely connected with groundwater. The complex surrounding water not only affects the groundwater quality through Chagan Lake, but also affects groundwater through the infiltration of vadose zone. In order to further study the characteristics of the migration of F- in the soil around Chagan Lake along with water flow in the vadose zone and its impact on groundwater, soil column experiments were carried out using soil collected in the field, combined with HYDRUS-1D to simulate the migration characteristics of F-. The model was verified by measured data, the sensitivity of each parameter was analyzed by the single-factor disturbance method, and the effect of F- on groundwater was simulated and predicted. The results showed that (1) the soil column experiment was carried out using transport solutions of different pH value. The time required for F- to penetrate the soil column under alkaline conditions was shorter, and the HYDRUS model used has a high degree of fitting. (2) The single-factor disturbance method is used to analyze the sensitivity of the parameters. The parameters that have a greater impact on the migration of fluoride ions in the soil are saturated hydraulic conductivity, adsorption coefficient, and soil bulk density. (3) In the prediction scenario, due to the adsorption and interception of the vadose zone, as the depth increases, the time it takes for F- to accumulate is also longer. The groundwater around Chagan Lake is relatively shallow, and surface F- in alkaline environment reaches the underground aquifer within 2 days. The F- concentration in the groundwater reaches its maximum before the end of the irrigation period. In neutral environment, the F- concentration in groundwater did not reach the maximum before the end of the irrigation period.

The input–output balance of microplastics derived from coated fertilizer in paddy fields and the timing of their discharge during the irrigation season

Polymer-based microcapsules derived from coated fertilizers are not recovered after use. Therefore, they are a source of microplastics to the agricultural lands and coastal areas of Japan. In this study, we investigated the input–output balance of microcapsules in three paddy fields and the timing of microcapsule discharge from the fields with the aim of developing effective techniques to reduce microcapsule discharge. Microcapsules were discharged from the paddy fields primarily during puddling, when the weir plate was overflowed, and when surface drainage was implemented. About 50% of the total discharge during the irrigation period occurred during puddling, which is a process for leveling paddy fields. Therefore, contamination of the surrounding environment by microcapsules from paddy fields can be effectively reduced by preventing the release of microplastics from paddy fields during puddling. We also showed that the total microcapsule discharge cannot be controlled solely by irrigation water management, such as by adjusting the height of the weir plate. We found that about 0.067–0.076% of the total number of microcapsules accumulated in the soil of the paddy fields was discharged during the irrigation season in 2020. Furthermore, 70% of the microcapsules discharged from one field in 2020 had resided in the soil for at least two years. The use as fertilizer coatings of biodegradable polymers that would degrade completely in the soil within a few years could therefore substantially reduce the amount of microplastics released into the ocean from agricultural fields, and their development is thus urgently needed.

Effects of pre-harvest deficit irrigation during the oil accumulation period on fruit characteristics, oil yield extraction, and oil quality in olive cv. Genovesa in an arid region of Argentina

The effect of pre-harvest deficit irrigation was studied as a tool to reduce fruit moisture and evaluate its influence on fruit characteristics, oil yield extraction, and oil quality. Two regulated deficit irrigation treatments (RDI) were evaluated over two seasons in a cv. Genovesa olive orchard. This study included a Control treatment, irrigated at 100% crop evapotranspiration over the season, and two RDI treatments, irrigated at 50% (RDI1) and 30% (RDI2) of Control. These treatments were applied from the end of pit hardening (mid-January) until harvest (early- April), when oil is accumulated in fruits. Fruit moisture decreased as the deficit irrigation period advanced, being significantly lower in RDI2 and RDI1 than in the Control treatment. Fruits harvested from the RDI2 treatment had lower moisture, dry mass and oil deposition, and higher maturation and pulp flavonoid compounds concentration than in RDI1 and Control. Pooled data across seasons showed that a 1% reduction in fruit moisture produced an increase of 0.16% in oil yield extraction. Phenolic compounds increased consistently with fruit moisture decreasing from 60% to 50%. However, when fruit moisture was as low as 35%, phenolic compounds were the lowest. Additional fruit samples from RDI2 were processed with water addition after malaxation. Water addition led to a general pattern of increases in oil yield extraction, reduction of phenolic compounds, and no influence on acidity, UV indexes, or fatty acids profile.

Desain Pintu Air Sekunder Berbantu Komputer Untuk Daerah Irigasi Cinangka Kabupaten Bogor

The most problem that occurs in Cinangka Irrigation Area is the not function of sluice and not used to properly regulate water of it. If the discharge regulator is not operated properly, the provision of irrigation water has the potential to be wasteful or lacking. The purpose of this study is to determine the discharge requirements for secondary irrigation water in Cinangka, produce a design of sluice in the channel and an estimated cost of manufacture. The study was conducted in the Cinangka Irrigation Area, Cibitung Tengah Village, Tenjolaya District, Bogor Regency. The study began from April - June 2020. The results obtained were known to be evapotranspiration, effective rainfall, and irrigation needs in the secondary channel of DI Cinangka per period of irrigation for one year. The largest Eto value occurred in September of 5.8 mm / day, the largest Cheff value occurred in November of 8.4 mm / day and the largest debit of needs occurred in March of 0.6 m3 / sec. Secondary sluice designed manifold steel sluice with high specification and door width 1x 1 m, total height 2 m door, handlebar diameter 45 cm. Dratstick used is 1.5 inches. Estimated cost for making doors is IDR 7,085,000. These costs can increase depending on the manufacture location and manufacture services.