Moisture Distribution Patterns Research Articles

Adding lignin to bagasse cellulose-based materials increases the wet strength and reduces micro-nano scale wet low-temperature defects

The enhancement of cellulose utilization in agricultural by-products, such as bagasse, holds significant importance in augmenting the value of secondary agricultural products. However, cellulose-based materials have limited application potential owing to their low strengths under wet and wet-low-temperature conditions. Improved mechanical properties of cellulose-based materials at wet and low temperatures can significantly enhance their suitability for application in cold chain processes. Furthermore, the effects of wet cryogenic conditions on cellulose-based materials are not well understood. In this study, composite films composed entirely of biomass are prepared via the co-solubilization of lignin and bagasse cellulose and then cured via hot pressing, which increases the wet and wet low-temperature strengths of the films. Furthermore, the mechanism by which cellulose/ lignin content influences the wet-low-temperature defects of films was investigated. Lignin self-polymerizes and hot pressing causes cross-linking in the cellulose-based films, which improves their performance in wet low-temperature environments. Furthermore, the micromorphologies, specific surface areas, and moisture distribution patterns of the cellulose films after wet -low-temperature treatment were investigated. The results indicate that cross-linking prevents large amounts of micro-nano scale free-water from entering the cellulose-based material, thereby preventing the formation of ice crystals at low temperatures, which can damage the microstructure. The results of this study can be used to develop bagasse cellulose/cellulose-based materials for applications in humid and low-temperature environments.

The role of moisture and salt distribution in the weathering of the medieval cave town of Uplistsikhe, Georgia

Knowledge of salt and moisture distribution is a key factor for understanding rock decay at cultural heritage sites. The cave town of Uplistsikhe in Georgia, carved from sandstone in late bronze age to medieval times, suffers from progressive scaling and flaking processes. Multi-method investigations of rock moisture and salt distribution were carried out in order to better understand the patterns of decay. Salt distribution was investigated using drill dust samples and paper pulp poultices; moisture was determined by 2D-resistivity and handheld microwave sensors, supplemented by infrared thermography. The combined results from the different methods revealed a complex pattern of salt and moisture distribution. At most sites, K2SO4 (arcanite) and its hydrates dominate, sometimes in combination with CaSO4 (gypsum). At one site (Grandhall), halite (NaCl) and niter (KNO3) prevail. Sulphates are assumed to be a legacy of air pollution; origin of halite and niter remains unsolved but might be due to concrete reinforcements. Two main sources of moisture were evidenced depending on season and spatial situation: (1) Condensation of air humidity at cool cave backwalls in spring (combined with and aided by salt hygroscopicity), evidenced by 2D-resistivity and infrared thermography; (2) seepage along joints particularly at the cave backwalls and roofs, evidenced by handheld microwave sensors. Further investigations should focus on identifying seepage pathways and on clarifying the origin of destructive halite and nitrates.

Influence of monsoon extreme rainfall on the distribution of upper tropospheric humidity

AbstractThis study focuses on the changes in the upper tropospheric humidity (UTH) associated with two different extreme precipitation conditions for the period 2000–2019 over the Indian summer monsoon region. The analysis embodies UTH datasets derived from microwave sounders on‐board NOAA and MetOp‐A polar‐orbiting satellites. The circulation characteristics in the upper troposphere are studied using the high‐resolution ERA5 reanalysis data. The analysis of UTH variability over the Indian region shows a unique positive (negative) UTH anomaly patch extending from northwestern regions of India to the northern Arabian Sea for the enhanced (deficient) rainfall days over central India during the southwest monsoon period. The investigation reveals that deep convection alone does not impact the UTH variability. Rather the circulation in the upper troposphere also plays a crucial role in UTH distribution. The dynamics in the upper troposphere cause large‐scale dispersal of both wet and dry air in the upper troposphere, which is linked to the strengthening/weakening of Asian monsoon anticyclone. The study indicates that monsoon extremes exhibit a distinct moisture distribution pattern in the upper troposphere, influenced by upper‐level dynamics, which are associated with the intensity of the Asian monsoon anticyclone.

Response of NPK Fertilization and Irrigation in Nutrient and Soil Moisture Distribution Under High-Density Apple Plantation in the NW Himalayan Region

ABSTRACT Drip fertigation provides enormous opportunities for the effective utilization and distribution of water and nutrients in sustainable management of orchard. Under various drip irrigation and fertigation schedules, the analysis of NO3 −-N and NH4 +-N distribution within the soil has been found to be efficacious to enhance the crop growth. Over the 2-year period of study (2019 and 2020), the response of NPK fertilization and irrigation in nutrient and soil moisture distribution under high-density apple plantation in the NW Himalayan region was investigated. In the present study, under drip irrigation, the wetting front extended up to 45 cm horizontally from the emitter; however, the maximum increase in soil moisture content remained confined near the emitting point. The soil moisture content decreased consistently with the increasing horizontal distance from the emitter. Drip irrigation recorded a higher soil moisture content at the surface soil depth of 0–15 cm compared to conventional surface irrigation, where the sub-surface soil depths of 15–30 cm registered a higher moisture content. The distribution of NO3 −-N and NH4 +-N content under drip fertigation nearly followed the soil moisture distribution pattern. The NO3 −-N and NH4 +-N content was maximum below the emitter and decreased thereafter with the increasing lateral distance from the emitter as nutrient mobility in soil is primarily governed by water movement. The decreasing trend of NO3 −-N and NH4 +-N with the increasing lateral distances is in accordance with the water distribution pattern under drip irrigation. The nutrient mobility is proved to be well pronounced under the drip fertigation system, and nutrients carried along with the water movement get concentrated near the outer periphery of the wetting zone.

Changes in Relative Humidity Profiles over Earth’s Oceans in a Warming Climate: A Satellite-Data-Based Inference

Abstract Recently, we presented a classification of “primitive” relative humidity (RH) profiles into eight distinct clusters over Earth’s oceans, based on about 18 years (2003–20) of observations from the AIRS on NASA’s Aqua satellite. Here we investigate the seasonal variability and decadal trends, both in the vertical structure of these RH profiles, and in their associated area of occurrence. Since vertical structures (except in the marine boundary layer) of each RH class are generally robust across all seasons and change only weakly in a warming climate, seasonal or decadal changes to their occurrence areas shift patterns of global moisture distribution. Globally, the marine boundary layer exhibits nonlinear moistening effects after about 2010, the end of the warming hiatus. Annual time series of ocean areas dominated by RH classes have linear trends, which are positive only for the most moist and driest RH classes (in terms of the free troposphere) associated with deep convection and large-scale subsidence favoring conditions for low-level stratocumulus clouds, respectively. Based on estimated linear trends of RH-class occurrences and sea surface temperatures, we infer projected linear responses of RH in a warming climate. Ocean areas dominated by most moist and driest RH classes (in terms of the free atmosphere) are estimated to increase by about 1% and 2%, respectively (corresponding to about 2.5% K−1 and 4.5% K−1, respectively). The averaged global and tropical RH structure remain almost constant in a warming climate. While this is consistent with other studies, our results show how increases in most moist and dry areas compensate each other, indicating possible increases in the frequency or persistence of future extreme events.

Impacts of moss-dominated biocrusts on rainwater infiltration, vertical water flow, and surface soil evaporation in drylands

Globally widespread biocrusts form a “living skin” on most dryland soils, helping govern fundamental ecosystem functions, particularly hydrological processes. However, the underlying mechanisms of biocrust effects on soil water infiltration and evaporation are still controversial. Biocrusts possibly regulate infiltration and evaporation due to their unique physicochemical properties and influence on surface soil moisture (θ), and these assumptions were verified in this study conducted on the Loess Plateau of China. The differences in vertical soil moisture distribution and flow patterns of infiltration water between moss-dominated biocrusts and bare soil were investigated through dye tracing experiments. The evaporation characteristics of biocrusts and bare soil were also obtained by weighing micro-lysimeters in both simulated and in-situ experiments. Results showed that biocrusts retarded deep soil water infiltration below ∼ 15 cm and significantly (F = 48.15, P < 0.001) decreased the stained area ratio (percentage of stained area to total area at the same soil depth) by 16% in contrast to bare soil. Because the infiltrated water was mostly retained in shallow soil (0–15 cm) in biocrust-covered soil, their ratios of low interaction flow (stained path width < 20 mm) and high interaction flow (20 mm < stained path width < 200 mm) were significantly higher (F ≥ 7.82, P ≤ 0.007) than those of bare soil. After the dye tracing experiments, the biocrusts modestly increased θ by 17% throughout the soil profile (0–50 cm), but they remarkably increased θ by 33%−78% in the top 20 cm of soil. Additionally, the biocrusts increased soil daily evaporation rate (E) by 27%−39% (with only the exception of the beginning) and the cumulative evaporation amount by 14% in contrast to bare soil over an 8-day field measurement. More importantly, the biocrust-affected soil properties, such as the contents of fine particles and organic matter, as well as saturated water content and field capacity, were closely correlated with E (|ρ| ≥ 0.52, P ≤ 0.08). Consequently, it was concluded that biocrusts restrict the depth of rainwater infiltration and increase surface θ, which may greatly enhance surface soil evaporation in the Chinese Loess Plateau.

Soil Penetration Resistance and Sugarcane Rooting Under Subsuperficial Drip Irrigation Levels

Knowledge of the soil water regime in a dynamic equilibrium condition (steady state) of the emitter–soil–plant system is essential to evaluate the adopted irrigation management, aiming to maximize the water use efficiency in irrigation. Thus, our objective was to determine the integrated effect of four irrigation levels on the soil moisture (θv) distribution pattern, mechanical soil penetration resistance (PR), and sugarcane rooting. Irrigation levels were established based on the percentage of reference evapotranspiration (ETo), as follows: 40% (W1), 70% (W2), 100% (W3), and 130% (W4) of ETo. From the soil moisture profile and PR versus θv regression models, PR profiles for each irrigation level were estimated. At the end of the crop cycle, trenches were opened to assess sugarcane root system. According to the results, the water dynamic in the soil profile resulted in a soil-wetting pattern that did not match the sugarcane rooting profile. For treatments W3 and W4 the wetting pattern indicated water loss through deep percolation. For all treatments and considering the entire soil profile, the PR values ranged from < 2 to 10 MPa. Also, the roots were superficially spread and limited to the first 0.35 m in depth for all irrigation depths applied. Although the soil wetting by irrigation reduced the strength of the cohesive layer, this reduction was insufficient to allow the deepening of plant roots. The su garcane root development was limited to the region of the soil profile defined by a PR value approximately equal to 2.0 MPa.

Soil moisture distribution pattern of surface drip irrigated mango

At present, Pakistan has been facing acute shortage of irrigation water and farmers have been using conventional irrigation methods for orchards, such as flood and basin irrigation, thus wasting huge amount of fresh water. Therefore, it is necessary to find efficient irrigation methods to cope with this major burning issue. The micro drip irrigation method is considered efficient but in the case of mango orchards there is a problem of irrigation frequency, number of emitters, and duration of flow from emitters to meet water demand. Considering the above, an experiment was conducted in the experimental field of the Sindh Agriculture University, Tandojam, by installing the drip system with two circular peripheries of lateral lines in clay loam soil covering the entire canopy of a mature mango tree. The radius of the first and second periphery around the tree trunk was 100 cm and 150 cm, respectively. Four emitters with 4 dm3∙h –1 discharge of individual dipper were fixed in each periphery. Emitters were tested for six different irrigation times, i.e. 1, 2, 3, 4, 5 and 6 h, to observe the moisture distribution pattern. Hydraulic characteristics, such as density, field capacity, porosity, infiltration rate, available water and permanent wilting point (PWP), were determined using standard methods (1.4 g∙cm –3, 33%, 49%, 8 mm∙h –1, 12.41% and 20% respectively). The texture class of the soil profile was determined as clay loam at the soil depth 0–120 cm. Fifty soil samples were collected at 0–10, 10– 30, 30–60, 60–90, and 90–120 cm depths and at 0–20, 20–40, 40–60, 60–80 and 80–100 cm distances on two opposite sides of emitters. The emitters provided sufficient moisture up to field capacity in clay loam soil with flow duration of 4 h. The maximum moisture distribution efficiency was 77.89% with flow duration of 4 h at vertical depth of 0–120 cm and 0–100 cm distance horizontally among four emitters as compared to 1, 2, 3 h flow duration which under irrigated the canopy area and 5, 6 h flow duration which excessively irrigated the canopy area of the mango tree. The water demand of the mango tree was met by 4 h flow duration which provided adequate moisture to the entire canopy up to 120 cm depth in the root zone and water saving was calculated as 15.91% under the installed drip irrigation system as compared with the conventional (basin) irrigation method.

Wind Drift Evaporation Loss and Soil Moisture Distribution under Sprinkler Irrigated Blackgram (Vigna mungo L.)

An experiment was conducted during March–June 2018 with the sprinkler irrigation system covered in an area of 39×42 m2. Proper design and management of sprinkler irrigation systems improves the uniformity of moisture distribution and reduces wind drift and evaporation losses (WDEL) for effective crop growth. Uniformity coefficient, wind drift and evaporation loss of the sprinkler system at a different pressure head of 2 kg cm-2, 2.5 kg cm-2 and 3 kg cm-2 were studied. Wind speed was observed by using handheld anemometer. The wind speed ranged between 0.9 to 4.5 m s-1. The highest uniformity coefficient of 88.19% and wind drift and evaporation loss of 3.5% were obtained at the pressure head of 3 kg cm-2 and the wind speed of 0.9 m s-1. Soil samples were collected at different depths of 0–10 cm, 10–20 cm, 20–30 cm and at a radial distance from 0 m, 3 m, 6 m, 9 m, 12 m respectively to determine the soil moisture distribution pattern. The soil moisture content values were plotted by using the computer software, surfer 10 of the windows version and contour maps were drawn. The moisture content was found to be more at 0–10 cm depth, as compared to 10–20 cm and 20–30 cm depth. The percentage of moisture was found to be highest at a 6 m distance, which was due to overlapping of the sprinkler system.

Effect of mulching on spatial moisture distribution pattern in Brinjal

Effect of mulching on spatial moisture distribution pattern in Brinjal

Modeling wetted areas of moisture bulb for drip irrigation systems: An enhanced empirical model and artificial neural network

Suitable design and management of drip irrigation systems depends on an accurate knowledge of the moisture distribution patterns around the emitters. An important parameter in the design of surface and subsurface drip irrigation systems is the wetted pattern of soil area in the up and down wetted areas of drippers. Accurate estimation of the up and down wetted areas in surface/subsurface irrigation systems is essential for enhancing the efficiency of irrigation systems and optimal management of water resources in the field. In this study, artificial neural network (ANN) and nonlinear regression (NLR) methods were used to develop equations for the estimation of the up and down wetted areas around the dripper installation position. Experiments were carried out in a transparent physical Plexiglas with dimensions of 3m×1.22m×0.5m. In this study, three different soil textures (i.e., light, medium, and heavy) were used. The drippers at four installation depths, including 0, 15, 30, and 45 cm, were evaluated. By considering an irrigation time equal to 6 h, the emitter discharge rates (i.e., 2.4, 4, and 6 L/s) were applied. Nine different variables, including soil hydraulic conductivity, emitter discharge, soil apparent density, irrigation application time, dripper installation depth, and the soil texture (i.e. amount of clay, silt and sand)were applied as inputs for the developed NLR and ANN models for estimating the up and down wetted areas of drippers. The comparison results between the measured and simulated values showed that the ANN and NLR models have appropriate performances and that the statistical error indices are within an acceptable range. The use of these models for design goals can be helpful in choosing the accurate distance between laterals and emitters as well as the suitable depth of emitters to minimize water losses via deep percolation in surface/subsurface drip irrigation. Furthermore, the results of the ANN and NLR models were compared with an experimental model (developed based on dimensional analysis (DA)) and confirmed the superiority of the ANN and NLR to DA models.

Prediction of climate specific vertical movement of pavements with expansive soils based on long-term 2D numerical simulation of rainwater infiltration

Long-term 2D simulation of rainwater infiltration into road embankments built on expansive soils is lacking in most highway design strategies. This paper explores the application of Hydrus-2D to establish a finite element model capable of performing long-term simulations of water flow in road embankments subjected to seasonal rainfall. Toward that end, climate specific suction profiles are generated from the simulations using real time climate data, which are used to predict vertical movement at the pavement edge. Sensitivity analyses show that the initial moisture condition has the most significant effect on moisture distribution and suction profile patterns. This induces a maximum decrease in vertical movement of 3.0 cm when a dry initial moisture state is compared with a wet initial moisture state. Higher values of evaporation rate and hydraulic conductivity result in less long-term vertical movement, although the impact is less obvious compared to initial moisture condition. The results also indicate that an extreme rain event can double the vertical displacement of pavements when compared to normal rain events, which proves the importance of using real climate data when expansive soils are involved. A case study presented the advantages of using Hydrus-2D suction profiles to predict vertical movement of pavements.

Paleoenvironmental reconstruction of the semi-arid Chaco region of Argentina based on multiproxy lake records over the last six hundred years

In this paper, we analyze the paleoclimatic and paleoenvironmental evolution of Laguna Yema in semi-arid Chaco region of Argentina over the past six hundred years. High resolution multiproxy studies of lake sediments utilize analyses of lithology, mineralogy, geochemistry, palynology, and are constrained by radiocarbon and gamma spectrometry dating. Laguna Yema sediments were mainly composed of well stratified fine sediments (silts and clays), with variable proportions of quartz, clays (illite) and feldspar (microcline and albite). Twelve light and heavy geochemical elements were registered. Most elements (Al, Si, K, Ti, Fe, Rb, Ba, and Br) are associated with illite and albite. Different material transport processes related to the changes in aridity and humidity of the basin were identified using the main mineralogical origins of geochemical elements. Palynological records indicate cycles of contraction and expansion of the lake, with an increase in concentration of Alternanthera aquatica during wet periods (expansion of lake), and an increase in Ambrosia, Poaceae and fern spores during dry periods (contraction of lake). These changes are linked to fluctuations in moisture conditions in the Subandean Mountains and semi-arid Chaco regions, in response to interactions between the South American Monsoon System (SAMS) and the South American Low Level Jet (SALLJ), which send warm and humid air to northern Argentina. In a regional context, the Laguna Yema records are in accordance with the analyses of the temporal and spatial pattern of moisture distribution for the last six centuries.

Effect of irrigation and fertigation scheduling on input use efficiency, yield and quality of guava cv. Lalit under intensive orcharding system

A study was conducted on guava cv. Lalit to find out the effect of irrigation and fertigation scheduling on WUE, FUE, moisture distribution pattern, leaf NPK content and nutrient uptake under intensive orcharding. The experiment consisted of 15 treatments combination comprising three different level of irrigation [50% (I1), 75% (I2) and 100% (I3) irrigation of pan evaporation] and five level of fertigation [20% (F1), 40% (F2), 60% (F3), 80% (F4) and 100% (F5) of recommended dose of NPK. Among the different treatment combination, maximum WUE (1038.50 kg ha−1 cm−1) was recorded under I1F4 treatment combination. Whereas, I3F5 resulted in maximum P content in leaves (0.28%), however, maximum yield plant−1 (6.75 kg), estimated yield ha−1 (33.75 t), uptake of N (652.92 kg ha−1), P (86.15 kg ha−1) and K (425.08 kg ha−1) were obtained under I2F4. Treatment combination I2F3 obtained a maximum net return (Rs. 2, 79,081.08) which was statistically at par with I2F4. Further, maximum B: C ratio (2.64) jointly recorded in I1F1 and I2F1, followed by (2.62) in I3F1. Treatments combination I2F3 and I2F4 were non significant between each other with respect to WUE, NPK uptake, yield tree−1 and estimated yield ha−1. Thus, based on the results of experiment we can conclude that treatment combination I2F3 (75% irrigation of PE + 60% of recommended dose of NPK) efficiently utilized water and fertilizers in form of yield in guava cv. Lalit under intensive orcharding system.

IMPROVING MOISTURE DISTRIBUTION PATTERN BY USING SOME SOIL CONDITIONERS IN LOAMY SAND SOIL UNDER DRIP IRRIGATION SYSTEM

A field experiment was carried out to study the conditioning effect of composted rice straw biochar (RSB) and synthetic cellulose polymer like carboxymethyl cellulose (CMC) on soil moisture distribution patterns, some plant growth parameters, yield and water use efficiency of squash plant (Cucurbita pepo L. var. Hybrid Revera). So, a complete randomized field experiment with three replications was conducted during the summer season of 2018 on a loamy sand soil at the Animal Production farm, Faculty of Agriculture, Al-Azhar University, Nasr City, Cairo, Egypt. The treatments were applying RSB by two rates (i.e. 840 and 1680 ) and CMC by two rates (i.e. 16.8 and 33.6 ) with 100% and 80% of squash water requirements. The obtained results indicated a positive effect on soil moisture distribution patterns, some plant growth parameters, yield and water use efficiency due to application of RSB with 100 and 80 of squash water requirements. Whereas, the soil was retained by the highest moisture content (18.8-15.0 ) and (15.4-10.6 ) with 100 and 80 at (0-40cm), respectively. The highest productivity was 7576.69 and 6436.69 when adding 100 and 80 of squash water requirements, respectively. Also, the highest irrigation water use efficiency was 9.33 and 9.91 of irrigation water when adding 100 and 80 squash water requirements, respectively. Finally, the obtained results indicate that adding rice straw biochar (RSB) to the planting medium at a low water irrigation rate of 80 increases the efficiency of water use by preventing applied moisture from infiltrating beyond plant root zones and maximizing the amount of applied water available for plant uptake. A field experiment was carried out to study the conditioning effect of composted rice straw biochar (RSB) and synthetic cellulose polymer like carboxymethyl cellulose (CMC) on soil moisture distribution patterns, some plant growth parameters, yield and water use efficiency of squash plant (Cucurbita pepo L. var. Hybrid Revera). So, a complete randomized field experiment with three replications was conducted during the summer season of 2018 on a loamy sand soil at the Animal Production farm, Faculty of Agriculture, Al-Azhar University, Nasr City, Cairo, Egypt. The treatments were applying RSB by two rates (i.e. 840 and 1680 ) and CMC by two rates (i.e. 16.8 and 33.6 ) with 100% and 80% of squash water requirements. The obtained results indicated a positive effect on soil moisture distribution patterns, some plant growth parameters, yield and water use efficiency due to application of RSB with 100 and 80 of squash water requirements. Whereas, the soil was retained by the highest moisture content (18.8-15.0 ) and (15.4-10.6 ) with 100 and 80 at (0-40cm), respectively. The highest productivity was 7576.69 and 6436.69 when adding 100 and 80 of squash water requirements, respectively. Also, the highest irrigation water use efficiency was 9.33 and 9.91 of irrigation water when adding 100 and 80 squash water requirements, respectively. Finally, the obtained results indicate that adding rice straw biochar (RSB) to the planting medium at a low water irrigation rate of 80 increases the efficiency of water use by preventing applied moisture from infiltrating beyond plant root zones and maximizing the amount of applied water available for plant uptake.

Modified Richards’ Equation to Improve Estimates of Soil Moisture in Two-Layered Soils after Infiltration

Soil moisture distribution plays a significant role in soil erosion, evapotranspiration, and overland flow. Infiltration is a main component of the hydrological cycle, and simulations of soil moisture can improve infiltration process modeling. Different environmental factors affect soil moisture distribution in different soil layers. Soil moisture distribution is influenced mainly by soil properties (e.g., porosity) in the upper layer (10 cm), but by gravity-related factors (e.g., slope) in the deeper layer (50 cm). Richards’ equation is a widely used infiltration equation in hydrological models, but its homogeneous assumptions simplify the pattern of soil moisture distribution, leading to overestimates. Here, we present a modified Richards’ equation to predict soil moisture distribution in different layers along vertical infiltration. Two formulae considering different controlling factors were used to estimate soil moisture distribution at a given time and depth. Data for factors including slope, soil depth, porosity, and hydraulic conductivity were obtained from the literature and in situ measurements and used as prior information. Simulations were compared between the modified and the original Richards’ equations and with measurements taken at different times and depths. Comparisons with soil moisture data measured in situ indicated that the modified Richards’ equation still had limitations in terms of reproducing soil moisture in different slope positions and rainfall periods. However, compared with the original Richards’ equation, the modified equation estimated soil moisture with spatial diversity in the infiltration process more accurately. The equation may benefit from further solutions that consider various controlling factors in layers. Our results show that the proposed modified Richards’ equation provides a more effective approach to predict soil moisture in the vertical infiltration process.

Soil moisture study under drip irrigated cabbage (Brassica oleracea L. var. capitata) in sandy loam soil

Field experiment was conducted at Plasticulture Farm, CTAE, Udaipur, Rajasthan during Rabi season of 2012-2013 and 2013-2014 on sandy loam soil to study the moisture distribution pattern of sandy loam soil under the drip irrigated cabbage at various irrigation and fertigation levels. The experiments were laid out in Factorial Randomized Block Design with ten treatments which included three irrigation levels 100, 80 and 60% of evapotranspiration (ET) along with three fertigation levels, viz., 100, 75 and 50% of recommended dose of fertilizer and one control (Surface irrigation at 1.0 IW/CPE ratio + 100% RDF through farmer’s practice) and were replicated thrice. Observations revealed that highest yield (340.73 q ha -1 ) was recorded with the treatment combination of drip irrigation with 80 % ET and fertigation @ 75 % RDF. The crops treated with 80 per cent ET experienced that the moisture content was maintained near to field capacity at the root zone of the crop. The vertical and radial spread of water in the soil increased with the amount of irrigation. In all the treatments, the soil moisture distribution along the vertical direction increased and laterally it was decreased.

Effect of Drip Irrigation System on Moisture and Salt Distribution Patterns under North Sinai Conditions

Effect of Drip Irrigation System on Moisture and Salt Distribution Patterns under North Sinai Conditions

Effect of inhibitors and fertigation strategies on GHG emissions, NO fluxes and yield in irrigated maize

Abating large losses of nitrogen (N) oxides while maintaining or enhancing crop yield is a major goal in irrigated maize (Zea mays L) cropping areas. During two consecutive campaigns, the new nitrification inhibitor 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinic acid isomeric mixture (DMPSA) applied with calcium ammonium nitrate (CAN) and the same fertilizer applied by drip-fertigation without the inhibitor, were evaluated and compared with CAN broadcast to the surface and irrigated with sprinklers. Concurrently, urea-based treatments such as urea-fertigation and the broadcast application of urea combined with sprinkler irrigation, with or without the urease inhibitor N-butyl thiophosphorictriamide (NBPT), were also assessed. Nitrous oxide (N2O) and nitric oxide (NO) fluxes, grain and biomass yield and yield-scaled N2O emissions of the different treatments were compared. Additionally, methane (CH4) and carbon dioxide (CO2) fluxes were measured. On average, fertigation treatments led to a mitigation of N2O emissions with respect to sprinkler irrigation by 80% and 78% for CAN and urea, respectively. With regards to inhibitor-based strategies, the use of DMPSA and NBPT reduced N2O losses by 58% and 51%, respectively, considering the average of both maize cropping seasons. Since no differences in grain yield were observed between fertilized treatments, DMPSA and fertigation treatments gave the lowest values of yield-scaled N2O emissions, leading to reductions of 63%, 71% and 78% for CAN with DMPSA, urea-fertigation and CAN-fertigation, respectively, with respect to conventional management strategies (surface broadcast application and sprinkler irrigation). Low NO emissions during the first campaign masked differences between treatments, whereas during the second season, NO losses significantly decreased in the following order: conventional treatments > inhibitors > fertigation. Comparing conventional management practices, CAN significantly decreased emissions of N oxides compared with urea, but this effect was only observed in the second maize cropping season. The moisture distribution pattern in drip plots (dry and wet areas) caused a reduction of CH4 sink (only in one of the two seasons) and respiration fluxes, in comparison to sprinkler. This study shows that the use of the new nitrification inhibitor DMPSA and drip-fertigation should be promoted in irrigated maize agro-ecosystems, in order to mitigate emissions of N oxides without penalizing grain yield and leading to similar or enhanced biomass production.

EFFECT OF MAGNETIZED WATER ON SOIL MOISTURE DISTRIBUTION AND DRIPPER DISCHARGE

Recent researches indicate that if water is exposed to intense magnetic field, it is possible to obtain many positive effects on water properties that improve water use in irrigation applications. The magnetized water is obtained by passing water through permanent magnets installed on a feed pipe line. Therefore, this work was carried out to investigate of irrigation by magnetic water and its effects on soil moisture distribution under ultra-low drip irrigation and dripper discharge. Three treatments of magnetic (0.325, 0.495 and 0 Tesla) was carried out by using three nominal drippers discharge of 0.5, 1.2 and 2.0 l/h under effect of different pressures of 50, 100, 150 and 200 kPa. The results indicated that the dripper discharge rate was increased by increasing the magnetic flux density at different dripper discharge rates and different operating pressures. Also, the moisture distribution pattern was increased horizontally more than vertically under dripper, by increasing the magnetic flux density at different operating pressures.