Irrigation Frequency Research Articles

Production of subsurface drip-irrigated okra under different lateral spacings and irrigation frequencies

In this study, an experiment was conducted to investigate the optimum lateral spacing and irrigation frequency for subsurface drip irrigated okra in the semi-arid region of Haryana (India). Two lateral spacings (45 cm and 60 cm) and four irrigation frequencies (daily, after 1, 2 and 3 days) were selected to grow okra in the Kharif season of 2019 and 2020. The effect on soil water dynamics, growth parameters, efficiency and yield were assessed using equal amounts of water under all the treatments on the basis of pan evaporation. The results from the study depict that the overall soil moisture decreased laterally, but increased vertically downward with the increase in the irrigation interval. On the basis of soil water dynamics, plant growth parameters, efficiency and yield of okra, it was concluded that subsurface drip irrigation with daily irrigation at 45 cm lateral spacing gives better performance than all other treatments in sandy loam soil. The present study highlights the significance of proper irrigation frequency and lateral spacing for maximum production of okra. Using these guidelines, the income of okra growers/farmers in the semi-arid region may be increased by choosing the best frequency and lateral spacing of subsurface drip irrigation.

The Contribution of Agronomic Management to Sustainably Intensify Egypt’s Wheat Production

In Egypt, recent shortfalls in the wheat supply from Russia and Ukraine have necessitated substantial increases in domestic production. As agricultural practices influence the yield of bread wheat, we assessed current production strategies in the wheat-based systems of Egypt and investigated their effects on wheat productivity in four study areas in the Nile Delta. We used a multi-stage random sampling technique to select 246 wheat-producing farmers and applied structured questionnaires to assess farming practices and crop performance attributes. Data were analyzed by using descriptive statistics, analysis of variances, and multiple regression models. Wheat farmers were on average 56 years old with about 30 years of farming experience. Land holdings were rather small, with an average of 1.05 hectares and a mean wheat yield of 6.4 metric tons (t)/hectare (ha). Farmers devote <20% of their cropland area to wheat. Of the large observed variation in wheat yield (4.2–8.5 t/ha), 59% was explained by differences in applied cropping practices in the multiple regression model. The application of mineral fertilizers was mostly inappropriate and unbalanced, with an overuse of nitrogen and phosphorus, the complete absence of potassium and micronutrient fertilizers, and insufficient rates of applied organic amendments. The type of the preceding summer crop and the irrigation frequency were found to be the most influencing factors, explaining 7.5% and 38% of the variation in wheat yields. The majority of farmers with low wheat yields irrigated their crops twice per season, while only 7% of high-yielding farmers applied the recommended irrigation frequency of >5 times per season. Most farmers had poor knowledge of modern agronomic practices and inadequate access to information. To enhance domestic production in Egypt, there is a need for fiscal incentives, permitting or stimulating wheat-producing farmers to devote larger shares of their cropland to wheat cultivation. In addition, policies must enable wheat producers to improve their productivity by implementing adequate and sustainable agricultural practices such as crop rotations, balanced mineral nutrient supply, and the use of organic amendments. However, the most important factors are interventions and technologies that improve provision and increase the use efficiency of irrigation water.

Productivity and profitability of drip fertigated wheat (Triticum aestivum) – mungbean (Vigna radiata) – maize (Zea mays) cropping system

An experiment was conducted at the research farm of ICAR-Indian Agricultural Research Institute, New Delhiduring 2019–20 and 2020–21 to study the productivity and economic viability of wheat (Triticum aestivum L.)–mungbean (Vigna radiata (L.) R. Wilczek)–maize (Zea mays L.) fertigated with 0, 60, 80, 100% recommended dosesof NPK and irrigated at 0.6 and 0.8 crop evapotranspiration (ETc) through subsurface (SSDI) and surface drip irrigation (SDI). The results were compared with the conventional practice of surface irrigation and soil application of 100% recommended doses of NPK. Grain yields of wheat, mungbean, maize and system wheat equivalent yield (SWEY) improved by 22.9, 7.2, 21.9 and 19.4%, respectively with increase in NPK fertigation doses from 60 to 100% and by 15.6, 9.2, 4.9 and 9.7% with the increase in irrigation frequency from 0.6 to 0.8 ETc. However, SDI and SSDI had equal system productivity (12.48 and 12.85 Mg/ha). The SWEY at 0.8ETc fertigated either with NPK80 or NPK100was statistically at par (14.2–15.9 Mg/ha) with the conventional practice (14.3–15.2 Mg/ha). The cash inflow, netincome and benefit cost ratio (BCR) of the cropping system also increased successively with increase in fertigationdoses and irrigation frequency. The net income and BCR followed the order maize>wheat>mungbean. The net income under SSDI at 0.8 ETc with NPK80 or NPK100 in wheat, mungbean, maize and system was 11–13, 88–105, 1-9 and 8–14% higher than the conventional practice. At 0.8 ETc and NPK100, BCR in SSDI (1.86) was higher than in SDI(1.71) and conventional system (1.67).

Effects of irrigation and nitrogen fertilizer management on wheat grain baking quality based on the SiriusQuality2 crop model

AbstractThe baking quality of wheat grain is significantly affected by irrigation and nitrogen fertilizer management. This study aimed to model the impacts of nitrogen and water stress on winter wheat grain protein composition using SiriusQuality2. SiriusQuality2 was calibrated by using sufficient nitrogen and water treatments and used to evaluate 16 treatments in semi‐arid regions. Then, simulated baking quality and yield over a past 51‐year period were used to screen and optimize the selected 203 management practices. The evaluated simulation results suggest that all relative root mean square errors were less than 0.3, and the simulation results were excellent or good. Irrigation and nitrogen fertilization were beneficial to yield and grain protein content (GPC), while grain baking quality had adverse responses to irrigation. The GPC no longer increased, and the baking quality decreased with excess nitrogen fertilization (262.5 kg ha−1). Increasing the irrigation frequency and days after sowing were always conducive to baking quality. The optimal management, with a basal dressing of 315‐kg ha−1 nitrogen fertilization and 180‐mm irrigation depth at the wintering stage and jointing stage, was selected. Optimized management practices could simultaneously meet the multiple requirements of high grain quality and yield.

Nitrogen loss via runoff and leaching from paddy fields with the proportion of controlled-release urea and conventional urea rates under alternate wetting and drying irrigation.

Alternate wetting and drying irrigation (AWD) can reduce non-point source pollution from paddy fields by mitigating field water depth. However, the influence of compounding modes of polymer-coated urea (PCU) and conventional urea (CU) on nitrogen (N) loss via runoff and leaching from paddy fields under AWD conditions remains unclear. To address this question, in this study, a 2-year field experiment was set up with three N management treatments: (a) 100% CU (N1), (b) 60% PCU + 40% CU (N2), and (c) 100% PCU (N3), at an equivalent N rate of 240kgha-1 that was applied to traditional continuously flooded (CI) and AWD systems. The results of this experiment showed a high-risk period of N loss from the paddy fields within 7 d after basal fertilization and 5days after tillering fertilization. AWD reduced irrigation frequencies by 3.5 times and total input of irrigation water by 38.1%, increasing water utilization from precipitation by 44.4% than CI and reducing the volume of runoff by 46.1% and leaching water by 22.1%. This reduced the total N (TN) loss through runoff and leaching under AWD. In the N2 and N3 treatment groups, N concentration in floodwater decreased from 33.8 to 24.9%, TN loss via runoff decreased by 35.3 to 25.0%, and leaching decreased by 41.7 to 30.3% from the paddy field compared to N1. With the same N mode, AWD showed a higher N uptake (from jointing to maturity stage) and rice yield compared to CI. Besides, N2 and N3 had higher N uptake compared to N1 under the two irrigation regimes. Moreover, the AWDN3 and AWDN2 treatments resulted in the lowest and second-lowest loss of TN via runoff (2.21 to 2.66kgha-1) and leaching (8.14 and 10.21kgha-1), respectively, from the paddy fields and had the relatively high N uptake in rice in the maturity stage. Remarkably, compared with N3, N2 had a comparable grain yield under CI; however, it showed a higher yield under AWD, suggesting that there is a positive interaction in the rice yield between the AWD and compounding N (PCU + CU) fertilization practice. Thus, AWD coupled with N2 could be recommended as a useful approach to reduce N loss via runoff and leaching from paddy fields, which could increase the grain yield of middle-season rice.

The Influence of Different Irrigation Scenarios on the Yield and Sustainability of Wheat Fodder under Hydroponic Conditions

Agriculture uses more water than any other resource to produce animal feed and wastes much of it through inefficiency. One possible alternative to solve this problem is hydroponically grown animal fodder, which under hydroponic conditions can achieve optimal results and, most importantly, use expensive resources, such as water, more efficiently. In the conducted research, different irrigation scenarios (IR1–IR6) were investigated when the water flow rate, irrigation frequency, and duration (IR1—1 l min−1, 4 times day−1, 120 s; IR2—2 l min−1, 4 times day−1, 120 s; IR3—3 l min−1, 4 times day−1, 120 s; IR4—1 l min−1, 8 times day−1, 60 s; IR5—2 l min−1, 8 times day−1, 60 s; and IR6—3 l min−1, 8 times day−1, 60 s) were changed during the hydroponic wheat fodder cultivation using a 7-day growth cycle. The results showed that the highest yield from the used seed was obtained in scenarios IR5 (5.95 ± 0.14 kg kg−1) and IR6 (5.91 ± 0.19 kg kg−1). In terms of frequency and irrigation duration, in IR1, IR2, and IR3, the average yield reached 4.7 ± 1.85 kg kg−1, and in scenarios IR4, IR5, and IR6, the average yield was 15.4% higher—5.55 ± 1.63 kg kg−1. The results obtained showed that by increasing the flow rate (from 1 l min−1 to 3 l min−1) and the frequency of irrigation (from 4 times day−1 to 8 times day−1), the yield increased by 32.5%, but the mass of the grown fodder per liter of water used simultaneously decreased by 50.6%. The life cycle assessment showed that although irrigation scenario IR4 had the most efficient use of water, the CO2 footprint per functional unit (FU) was the highest due to the lowest yield compared to the other five irrigation scenarios. The lowest environmental impacts per FU were obtained in scenarios IR5 and IR6 (100.5 ± 3.3 and 100.6 ± 2.4 kg CO2eq t−1, respectively).

Effect of Different Watering Regimes on Morphological Parameters of Cashew Grafted Genotypes

Water stress has a strong influence on the physiological functions of tree crops which adversely affects the growth and yield of tree plants. Drought and soil fertility are the major factors that influence seedling survival and growth in arid areas, thus it is of paramount importance to establish optimum water requirements for tree seedlings in order to promote growth. In line with this, an investigation was carried out to assess early growth behaviours of Anacardium occidentale when exposed to varied watering intervals in the greenhouse. Two month old grafted seedlings were used for the study in 1.08 liter plastic pots containing 2 kg of potting soil. Seedlings were exposed to five different watering intervals (every two days, every four days, every six days, every eight days and ten days) and 80 mL of water was administered per each seedling based on the watering frequency for two months. Six seedlings were allocated per watering frequency and replicated 4 times in a Split-plot design. The result revealed a significant effect of irrigation frequency on seedlings growth of Anacardium occidentale where seedlings that received water every two days and every four days produced highest growth in the variables measured. Administering 80 mL of water per seedling every two days and every four days improved growth of A. occidentale in the nursery.

Mycotoxins and Crop Yield in Maize as Affected by Irrigation Management and Tillage Practices

In addition to the weather conditions, agronomic practices can have a major influence on maize crop yield and contamination with mycotoxins. In this work, the effect of different irrigation systems (flood vs. sprinkler irrigation), sprinkler irrigation management (low vs. high frequency, daytime vs. nighttime irrigation) and tillage practices (conventional tillage, no tillage with or without crop stover) on crop yield and the contamination with aflatoxins (AFs), fumonisins (FUM) and deoxynivalenol (DON) were evaluated in the maize grain from two experimental maize fields. No aflatoxins were detected in any of the samples analyzed. DON and FUM levels were significantly higher when the sprinkler irrigation was performed at nighttime (0.54 and 1.21 mg kg−1, respectively) as compared to daytime (0.38 and 0.45 mg kg−1). Likewise, DON and FUM were greater when irrigation frequency was low (0.61 and 1.09 mg kg−1, respectively) in comparison with high frequency (0.30 and 0.57 mg kg−1). DON concentrations were significantly higher in fields with sprinkler irrigation (0.53 mg kg−1) as compared to flood irrigation (0.19 mg kg−1), while the levels of FUM were very similar regardless of the maize irrigation system. Mycotoxin concentrations were not affected by the different soil tillage practices. This highlights the importance of implementing crop management practices to minimize the risk of mycotoxin contamination in maize.

Irrigation Timing Retrieval at the Plot Scale Using Surface Soil Moisture Derived from Sentinel Time Series in Europe

The difficulty of calculating the daily water budget of irrigated fields is often due to the uncertainty surrounding irrigation amounts and timing. The automated detection of irrigation events has the potential to greatly simplify this process, and the combination of high-resolution SAR (Sentinel-1) and optical satellite observations (Sentinel-2) makes the detection of irrigation events feasible through the use of a surface soil moisture (SSM) product. The motivation behind this study is to utilize a large irrigation dataset (collected during the ESA Irrigation + project over five sites in three countries over three years) to analyze the performance of an established algorithm and to test potential improvements. The study’s main findings are (1) the scores decrease with SSM observation frequency; (2) scores decrease as irrigation frequency increases, which was supported by better scores in France (more sprinkler irrigation) than in Germany (more localized irrigation); (3) replacing the original SSM model with the force-restore model resulted in an improvement of about 6% in the F-score and narrowed the error on cumulative seasonal irrigation; (4) the Sentinel-1 configuration (incidence angle, trajectory) did not show a significant impact on the retrieval of irrigation, which supposes that the SSM is not affected by these changes. Other aspects did not allow a definitive conclusion on the irrigation retrieval algorithm: (1) the lower scores obtained with small NDVI compared to large NDVI were counter-intuitive but may have been due to the larger number of irrigation events during high vegetation periods; (2) merging different runs and interpolating all SSM data for one run produced comparable F-scores, but the estimated cumulative sum of irrigation was around −20% lower compared to the reference dataset in the best cases.

The growth impact of Capsicum annuum crops in hydrogel incorporated media

Increasing food and water security via sustainable agriculture is vital, particularly in light of climate change. Researchers and farmers have recently shown a great deal of interest in the agricultural applications of hydrogels. This research aims to evaluate the impact of hydrogel on Capsicum annuum crop productivity and irrigation water use effectiveness. In a polybag containing a specifically formulated mixture of hydrogel and topsoil, the pepper variety cv Bara was contained. The use of 20%, 40%, 60%, 80%, and 100% biodegradable hydrogel doses per plant was also investigated. The treatment schedule was established using a random complete block strategy. Investigated factors included water usage, irrigation frequency, plant height, leaf number, leaf area, and leaf area index. According to the study’s findings, 40 percent hydrogel and 60 percent topsoil per plant produced the optimum growth characteristics. The results of the study indicate that hydrogel able to hold water, circulating water into the media and enhancing the water usage efficiency of pepper crops without affecting plant growth.

Effect of drip irrigation on seed yield, seed quality and water use efficiency of Hedysarum fruticosum in the arid region of Northwest China

Shortage of high-quality seeds of native species, particularly for xerophyte shrubs, have severely limited grassland restoration in the arid region of China. However, little attention has been devoted to improving seed yield and quality in the xerophyte shrub. We conducted a three-year field experiment from 2019 to 2020 to investigate the effects of four irrigation treatments (i.e., W0: non-irrigated control; W1: irrigation at winter; W2: irrigation at winter and regreening; W3: irrigation at winter, regreening, and peak flowering) via subsurface drip irrigation on the seed yield and quality of Hedysarum fruticosum, a dominant leguminous shrub in the desert areas of China. The results showed that seed yield increased as irrigation frequency increased regardless of growth season. The yearly average seed yields were 98.0, 107.7, 179.3, and 265.5 kg hm−2 for W0, W1, W2, and W3 irrigation, respectively. Seed yield decreased in each subsequent growth year in all irrigation treatments, and the variation in seed yield each year was the highest in W0 and lowest in W3 irrigation. Compared to 2019, the seed yield of W0 decreased by 47 % and 66 %, but yields of the W3 irrigation treatment decreased by 8 % and 19 % in 2020 and 2021, respectively. Meanwhile, irrigation significantly affected seed yield components; the number of florets and pods per stem under the W3 irrigation treatment was two to three times that of W0 irrigation for three years. The structural equation model revealed that pods per stem had the largest direct positive effect on seed yield (path factor p = 0.44), followed by seeds per pod (path factor p = 0.36). Irrigation treatments affected seed germination percentage and seed size, which increased as irrigations times increased. A similar water use efficiency was achieved in W0 and W3 in three years, and W1 treatment had the lowest water use efficiency. In conclusion, we recommend W3 treatment to increase seed yield and quality, especially in arid regions. Future breeding objectives and agronomic practice for H.fruticosum should pay more attention to increasing pods per stem. Our study can be used as a reference for taking appropriate agronomic measures to improve the seed yield of H.fruticosum and similar shrubs.

Integrating a novel irrigation approximation method with a process-based remote sensing model to estimate multi-years' winter wheat yield over the North China Plain

Accurate estimation of regional winter wheat yields is essential for understanding the food production status and ensuring national food security. However, using the existing remote sensing-based crop yield models to accurately reproduce the inter-annual and spatial variations in winter wheat yields remains challenging due to the limited ability to acquire irrigation information in water-limited regions. Thus, we proposed a new approach to approximating irrigations of winter wheat over the North China Plain (NCP), where irrigation occurs extensively during the winter wheat growing season. This approach used irrigation pattern parameters (IPPs) to define the irrigation frequency and timing. Then, they were incorporated into a newly-developed process-based and remote sensing-driven crop yield model for winter wheat (PRYM–Wheat), to improve the regional estimates of winter wheat over the NCP. The IPPs were determined using statistical yield data of reference years (2010–2015) over the NCP. Our findings showed that PRYM–Wheat with the optimal IPPs could improve the regional estimate of winter wheat yield, with an increase and decrease in the correlation coefficient (R) and root mean square error (RMSE) of 0.15 (about 37%) and 0.90 t ha–1 (about 41%), respectively. The data in validation years (2001–2009 and 2016–2019) were used to validate PRYM–Wheat. In addition, our findings also showed R (RMSE) of 0.80 (0.62 t ha–1) on a site level, 0.61 (0.91 t ha–1) for Hebei Province on a county level, 0.73 (0.97 t ha–1) for Henan Province on a county level, and 0.55 (0.75 t ha–1) for Shandong Province on a city level. Overall, PRYM–Wheat can offer a stable and robust approach to estimating regional winter wheat yield across multiple years, providing a scientific basis for ensuring regional food security.

Study on the In-Field Water Balance of Direct-Seeded Rice with Various Irrigation Regimes under Arid Climatic Conditions in Egypt Using the AquaCrop Model

Crop growth models are cost-effective and user-friendly tools for decision-makers to develop efficient in-field management strategies. These models are particularly important in countries such as Egypt, where the risk of water scarcity is inevitable. The present study aimed to examine the in-field water balance of direct-seeded rice (Giza 178) under various irrigation regimes and arid conditions during two growing seasons (2019 and 2020). Four irrigation regimes, namely, continuous flood irrigation with a fixed water depth of 5 cm, and 3-, 6-, and 10-day irrigation frequencies (FI, 3IF, 6IF, and 10IF, respectively), were arranged in a randomized complete block design with three replicates. Then, the feasibility of using AquaCrop in simulating direct-seeded rice development and in-field water balance was assessed. Five statistical indicators, including normalized root-mean-squared error (NRMSE), index of agreement (d), coefficient of determination (R2), Nash–Sutcliffe efficiency coefficient (EF), and percent deviation (Pd), were used to evaluate the performance of AquaCrop. The field trial results demonstrated that both the 3IF and 6IF irrigation regimes were the best for achieving the highest biomass (21.0 t·ha−1, under 3IF), yield (9.8 t·ha−1, under 3IF), and saving irrigation water (18.3–22.4%, under 6IF), making them the best to apply in Egypt. Moreover, the AquaCrop simulation results showed a good correlation between the observed and simulated rice yield (Y) in both seasons (R2 = 0.99 and 0.98 in 2019 and 2020, respectively). AquaCrop showed excellent performance in simulating canopy cover (CC) and biomass (B) during both growing seasons (5.0 ≤ NRMSE ≤ 15.0, 0.97 ≤ d ≤ 0.99, 0.92 ≤ R2 ≤ 0.99, and 0.92 ≤ EF ≤ 0.99). In addition, the model showed acceptable performance in simulating in-field water balance components. Reasonably good model efficiency was recorded in simulating crop actual evapotranspiration (ETact). Meanwhile, the average Pd for percolation (P) was between −15.3% and 5.4% during both growing seasons. Overall, AquaCrop showed adequate accuracy in simulating CC, B, Y, ETact, and P but relatively low efficiency in simulating ETact and P under severe water scarcity. Therefore, AquaCrop may serve as a valuable tool for irrigation management and crop yield prediction even in arid regions, such as Egypt.

Irrigation and drainage in pineapple crop (cultivar MD-2) in Ciego de Ávila province

The pineapple cultivar MD-2 was introduced in Cuba at the end of the year 2009 and the results obtained in the irrigation in Ceballos Agroindustrial Enterprise have not been satisfactory, being presented manifestations of excess of humidity with the affectation to the crop. With a view to value the conditions of management of the water under the given conditions and to propose the corresponding measures, a study of the irrigation and drainage conditions was carried out in the areas studied and the evaluation of the exploitation of the central pivot machine was carried out according to the NC 11545:2004 and the diagnosis of the problem of the drainage. The results indicate low quality of the irrigation with values of coefficient of uniformity of 66 % and of efficiency of discharge of 71 %. The irrigation system was calculated obtaining 
 for the critical stage with a net norm of 152 m3 /ha and a frequency of irrigation of 7 days, being concluded with the presentation of the technical chart for the adjustment of the module of nozzles and the calculation of the regulation of the machine. It was determined that the hardening of the soil is the main factor that impacts the present drainage problems. There are indicated recommendations on the irrigation technologies, which can be used to develop the crop and solve the current drainage problems.

Potato Waste Reduction Mechanisms: A case study in Abshar district of Panjshir Province, Afghanistan

The objective of the current study is to estimate the amount of potato waste and introduce suitable mechanisms to reduce it in different stages of production. The investigation was done based on primary data in the year 2021-22 and Abshar district of Panjshir province was selected through cluster sampling process as study area. The data was collected through questionnaires which were distributed randomly to 40 farmers in the district. The results revealed that the average gross income, costs and net income of farmers was estimated around about 1941.55, 414,06 and 1527.49 US$, respectively. Average production of farmers was recorded 9.46 tonnes and average productivity was found 12.21 tonnes ha-1. The highest quantity of potato waste was observed during planting and post-harvest periods. Proper planting date, frequency of irrigation, full ripening, keeping in standard storages and separating injured potatoes were the most important factors effective in waste reduction.

The Effect of Wool Mulch on Plant Development in the Context of the Physical and Biological Conditions in Soil.

Mulching techniques can comprise a solution that better utilizes precipitation and irrigation water in such a manner that mitigates soil degradation and drought damage; however, there are still gaps in the literature with regard to the effect of the use of mulch materials on the development of plant-soil-microbe interactions. Waste fibers, as alternative biodegradable mulch materials, are becoming increasingly prominent. The effect of wool mulch (WM) on water use efficiency, with regard to pepper seedlings, was investigated in different soil types (sand, clay loam, peat) in a pot experiment. Two semi-field experiments were also set up to investigate the effect of WM-plant interactions on sweet pepper yields, as compared with agro textiles and straw mulches. Soil parameters (moisture, temperature, DHA, β-glucosidase enzymes, permanganate-oxidizable carbon) were measured during the growing season. The effect of WM on yield and biomass was more significant with the less frequent irrigation and the greater water-holding capacity of soils. Microbiological activity was significantly higher in the presence of plants, and because of the water retention of WM, the metabolic products of roots and the more balanced soil temperature were caused by plants. In the sandy soil, the straw mulch had a significantly better effect on microbiological parameters and yields than the agro textiles and WM. In soils with a higher water capacity, WM is a sustainable practice for improving the biological parameters and water use efficiency of soil. The effect of WM on yields cannot solely be explained by the water retention of the mulch; indeed, the development of biological activity and plant-soil-microbe interactions in the soil are also contributing factors.

Different Sources, Fractionation, and Migration of Legacy and Novel Per- and Polyfluoroalkyl Substances between Greenhouse and Open-Field Soils.

Perfluoroalkyl substances (PFASs) are widely present in agricultural soils, but their sources and fate in greenhouse soils remain unclear. In this study, the sources, fractionation, and migration of PFASs were compared in the greenhouse and open-field soils of the Fen-Wei Plain, China. The total concentrations of PFASs (Σ17PFAS) were comparable in the greenhouse and open-field soils but with different profiles. Detrended correspondence and correlation analyses indicated that dry deposition was an important source of PFASs in the open-field soils, whereas surface water had a notable contribution to the greenhouse soils due to more frequent irrigation. The PFASs in the soils were mainly present in water-soluble fraction (F1). The F1 proportions of short-chain and long-chain PFASs were negatively correlated with the anion exchange capacity (AEC) and organic carbon content (foc) in soil, respectively, with that of short-chain PFASs being higher than long-chain ones. The AEC was significantly higher while foc was lower in the greenhouse soil than the open-field soil, leading to lower proportions of F1 for short-chain PFASs while higher for long-chain ones in the greenhouse soil. Frequent irrigation and elevated temperatures promoted the migration of PFASs in greenhouse soil; thus, the Σ17PFAS and F1 exhibited an increasing trend with soil depth.

Assessment of Irrigant Agitation Devices in Simulated Closed and Open Root Canal Systems

IntroductionThe in vitro efficacy of irrigant activation devices has not been contrasted to their safety. This was attempted in this study using apically closed versus patent simulated root canal systems in epoxy resin models, with the latter featuring a simulated periapical lesion. MethodsAll 72 models had 2 joining canals connected by an isthmus, which was filled with dentin debris. The simulated periapical lesion was filled with colored gelatin in the 36 respective models. Canals were irrigated with 1.3% sodium hypochlorite. Samples were divided into 4 subgroups per system (n = 9): conventional irrigation, sonic low (EndoActivator; Dentsply Sirona, Charlotte, NC) and high frequency (EDDY; VDW, Munich, Germany), and ultrasonic agitation of the irrigant (always applying 3 cycles of 20 seconds). The total cleared surface areas (mm2) in the simulated isthmus and periapical lesion were compared between systems and devices using parametric tests (P < .05). ResultsThe cleaning of the isthmus was more effective in the apically open compared with the closed systems and was also significantly influenced by the agitation method (P < .001). In the closed systems, EDDY and ultrasonic agitation achieved the significantly (P < .05) best cleaning of the isthmus. In the open systems, ultrasonic agitation showed the single best result (P < .05). EDDY caused by far the highest and ultrasonic agitation the lowest dissolution of the gelatin in the simulated periapical lesion. ConclusionsUnder the conditions of this study, ultrasonic agitation of a previously administered sodium hypochlorite irrigant was more laterally targeted and thus safer and more effective than sonic agitation methods.

Effect of Irrigation Scheduling Methods on Maize Grain Yield and Nitrate Leaching in Central Minnesota

Highlights Four irrigation scheduling methods were compared for maize yield vs nitrate-N losses. Yield was similar with SM, CB, and EPIC, and lower for IMA irrigation scheduling. Nitrate-N leaching losses were highly dependent on precipitation as well as on the rate and frequency of irrigation. IMA and EPIC methods should be adopted with further calibration. ABSTRACT. Coarse-textured soils in the Great Lakes states have limited water holding capacity, which makes irrigation essential to obtain optimum yields for maize; however, excess irrigation has the potential to contaminate ground and surface water resources through deep seepage of applied fertilizers, making irrigation management critical. The objective of this study was to evaluate the impact of different strategies for agricultural irrigation water management on maize grain yield and nitrate leaching losses. In this three-year study (2019-2021), the following four irrigation scheduling strategies were compared under continuous maize cropping systems at two sites in Central Minnesota, Becker and Westport: (1) soil moisture monitoring using soil moisture sensors (SM), (2) checkbook method of irrigation scheduling (CB), (3) irrigation management assistant tool (IMA), and (4) EPIC model auto-irrigation (EPIC). Overall, in comparison to the CB method (highest irrigation method), the SM, IMA, and EPIC methods recommended 2.58%, 51.05%, and 9.27% less water in irrigation, respectively. In terms of grain yield, no significant differences were observed between irrigation treatments at the Becker site. The average maize grain yield at the Becker site was 12.02, 11.97, 11.76, and 10.62 Mg/ha, for SM, CB, EPIC, and IMA treatments, respectively. However, in the drier 2021 season, a grain yield loss of 30%, 27%, and 21% was observed under IMA when compared to SM, CB, and EPIC methods, respectively, at the Becker site. At the Westport site, on average, no significant difference in yield was obtained between SM, CB, and EPIC, however, yield under IMA treatment was significantly lower (12%) than CB. The results suggest that nitrate leaching losses can be significantly reduced by altering the rate and frequency of irrigation. IMA treatment resulted in significantly lower nitrate leaching (62%) than the CB method, reducing nitrate leaching from 35.86 kg/ha to 13.71 kg/ha at the Westport site. No significant differences in nitrate leaching were observed at the Becker site because the impact of precipitation superseded the impact of irrigation. Results from this study can aid in the adoption and further development of less labor-intensive and more accurate methods of irrigation scheduling in coarse-textured soils of Great Lakes states. Keywords: Coarse textured soils, Crop evapotranspiration, Irrigation scheduling methods, Maize grain yield, Nitrate-N leaching, Water quality, Water quantity.

Irrigation Management in the Paricá Seedlings Development in Amazon Region

Paricá is a native tree to the Amazon region recognized for several socioeconomic applications. However, there are few studies on the influence of irrigation regime in the seedling stage. Thus, the objective of the research was to evaluate the effect of water depths and irrigation frequency on the development of Paricá seedlings in the edaphoclimatic conditions of the Amazon region. The experiment was conducted in a greenhouse at the Federal Rural University of the Amazon (UFRA), Capitão Poço Campus, located in Capitão Poço, Pará, Brazil. The experimental design was randomized blocks, in 5x2 factorial arrangements, consisting of five irrigation depths and two irrigation frequencies, with four replications. The highest irrigation depth (725 mL) at daily frequency resulted in lowest biomass production maybe due to hypoxia in the root zone. In contrast the every three day irrigation promoted high biomass production with the highest irrigation depth (725 mL). Contrarily, 435 mL depth produces high quality seedlings at daily irrigation frequency. Regarding the rational use of water, producers may use 725 mL at 3-day frequency, given that it has promoted high seedling quality and provides savings of 580 mL compared to the best water depth on the daily irrigation (435 mL).