scholarly journals Irrigation with domestic wastewater: a multivariate analysis of main soil changes

2010 ◽  
Vol 34 (4) ◽  
pp. 1427-1434 ◽  
Author(s):  
Thomas Vincent Gloaguen ◽  
Roberta Alessandra Bruschi Gonçalves ◽  
Maria Cristina Forti ◽  
Yves Lucas ◽  
Célia Regina Montes

Irrigation with treated domestic sewage wastewater (TSE) is an agricultural practice to reduce water requirements of agroecossystems and the nutrient load impact on freshwaters, but adverse effects on soil chemical (salinization, sodification, etc.) and soil physical properties (alteration in soil porosity and hydraulic conductivity, etc.) have been reported. This study aimed to define some relationships among these changes in an Oxisol using multivariate analysis. Corn (Zea mays L.) and sunflower (Helianthus annuus L.) were grown for two years, irrigated with TSE. The following soil properties were determined: Ca2+; Mg2+; Na+; K+ and H + Al contents, cationic exchangeable capacity (CEC), sum of bases (SB), base saturation (V), texture (sand, silt and clay), macro-, micro-, and cryptoporosity (V MA, V MI and V CRI), water content at soil saturation (θS) and at field capacity (θFC), residual water content (θR), soil bulk density (d s), water dispersed clay (WDC) and saturated hydraulic conductivity (K SAT). Factor analysis revealed the following six principal factors: Fine Porosity (composed of Na+; K+; WDC, θR, θRFC, and V CRI); Large Porosity (θS, d s, V MA, Vs); Soil CEC (Ca2+; Mg2+; CEC, SB, V); Soil Acidity (H + Al); and Soil Texture (factors 5 and 6). A dual pore structure appears clearly to the factors 1 and 2, with an apparent relationship between fine porosity and the monovalent cations Na+ and K+. The irrigation (with potable sodic tap water or sewage wastewater) only had a significant effect on Fine Porosity and Large Porosity factors, while factors 3 and 4 (Soil CEC and Soil Acidity) were correlated with soil depth. The main conclusion was a shift in pore distribution (large to fine pores) during irrigation with TSE, which induces an increase of water storage and reduces the capacity of drainage of salts.

2021 ◽  
Author(s):  
Liu Wenxiang ◽  
Yu Hanqing ◽  
Lu Yang

<p>A large number of radionuclides, produced by nuclear accidents or nuclear waste, may cause radioactive contamination in the agricultural and aquatic ecosystems. Under these circumstances, it is necessary to optimize the remediation of agricultural areas polluted by radionuclides using innovative monitoring and prediction techniques. To mitigate radioactive contamination in farmland soil and effectively protect groundwater, some measures should be taken against on field investigation, laboratory experiment and model prediction. In this study, the HYDRUS-1D model was used to simulate the vertical migration of <sup>137</sup>Cs and <sup>60</sup>Co in farmland soil in northern China calibrating by the soil lysimeter experiment, and the scenario simulations of <sup>137</sup>Cs and <sup>60</sup>Co migration were conducted under different radioactive levels. Results showed that the order of sensitivity in saturated water content (θ<sub>s</sub>), residual water content(θ<sub>r</sub>), saturated hydraulic conductivity(K<sub>s</sub>) and distribution coefficient (K<sub>d</sub>) applied in HYDRUS 1D model was K<sub>d</sub> > θ<sub>s</sub> > θ<sub>r</sub> >K<sub>s</sub>. The simulated concentrations ​​of <sup>137</sup>Cs and <sup>60</sup>Co in Brown soil and Aeolian sandy soil on day 175 and 355 were significantly positively correlated with the measured values​​ (r>0.90, p<0.01). The verification results showed that the predictive values on the 577<sup>th </sup>day were also significant positive correlated with the measured values ​​(r>0.90, p<0.01). The RMSE, CRM and NRMSE calculating by simulated and measured values ​​of <sup>137</sup>Cs and <sup>60</sup>Co in soil were very small, indicating that HYDRUS 1D can be used to simulate the migration of radionuclides in farmland soil. Scenarios simulation results revealed that radionuclides were concentrated in the surface layer within 5 cm, but the migration depth has exceed 10 cm soil depth, and even reaches up to 23.5 cm depth at high concentration level. The surface soil should be cleaned timely to protect groundwater with high level from radioactive contamination and further study should be done about horizontal transport and numerical simulation.</p>


2021 ◽  
Author(s):  
Brigitta Szabó ◽  
Melanie Weynants ◽  
Tobias Weber

<p>We present improved European hydraulic pedotransfer functions (PTFs) which now use the machine learning algorithm random forest and include prediction uncertainties. The new PTFs (euptfv2) are an update of the previously published euptfv1 (Tóth et al., 2015). With the derived hydraulic PTFs soil hydraulic properties and van Genuchten-Mualem model parameters can be predicted from easily available soil properties. The updated PTFs perform significantly better than euptfv1 and are applicable for 32 predictor variables combinations. The uncertainties reflect uncertainties from the considered input data, predictors and the applied algorithm. The euptfv2 includes transfer functions to compute soil water content at saturation (0 cm matric potential head), field capacity (both -100 and -330 cm matric potential head) and wilting point (-15,000 cm matric potential head), plant available water content computed with field capacity at -100 and -330 cm matric potential head, saturated hydraulic conductivity, and Mualem-van Genuchten parameters of the moisture retention and hydraulic conductivity curves. The influence of predictor variables on predicted soil hydraulic properties is explored and suggestions to best predictor variables given.</p><p>The algorithms have been implemented in a web interface (https://ptfinterface.rissac.hu) and an R package (https://doi.org/10.5281/ZENODO.3759442) to facilitate the use of the PTFs, where the PTFs’ selection is automated based on soil properties available for the predictions and required soil hydraulic property.</p><p>The new PTFs will be applied to derive soil hydraulic properties for field- and catchment- scale hydrological modelling in European case studies of the OPTAIN project (https://www.optain.eu/). Functional evaluation of the PTFs is performed under the iAqueduct research project.</p><p> </p><p>This research has been supported by the Hungarian National Research, Development and Innovation Office (grant no. KH124765), the János Bolyai Research Scholarship of the Hungarian Academy of Sciences (grant no. BO/00088/18/4), and the German Research Foundation (grant no. SFB 1253/12017). OPTAIN is funded by the European Union’s Horizon 2020 Program for research and innovation under Grant Agreement No. 862756.</p>


2020 ◽  
pp. 105678952097441
Author(s):  
Hao Wang ◽  
Kexin Zhang ◽  
Lin Gan ◽  
Jiaqin Liu ◽  
Guoxiong Mei

The objectives of the study are to explore fundamental mechanism of expansive soil-biochar-root-water-bacteria interaction, and investigate crack development and hydraulic properties of biochar amended soils aiming at green infrastructures. The physical, chemical and biological effects of biochar on expansive soil have been comprehensively explored. Crack development is investigated quantificationally, and mechanism of soil damage evolution is briefly discussed base on micro-chemical analyses. During outdoor vegetation period, photosynthesis light response curves were measured to evaluate plant growth. After period of vegetation, hydraulic properties of root-soil composites and unplanted soils were compared. The study reveals that soil crack intensity factor decreases by 33.5%, 48.5% and 47.3% due to 5%, 10% and 15% biochar introduction respectively after 5 wetting-drying cycles. 15% biochar amendment helps to restrain both initiation and propagation of soil cracks. Biochar amendment of up to 5% contributes well to residual water content and plant growth (i.e., light saturation point and light compensation point). Excessive biochar addition would restrain roots elongation, and increase saturated water content. Spatial root distribution is changed due to biochar addition, which further influences hydraulic properties and crack development. Hydraulic conductivity and soil dry density share negative correlations, 5% biochar enhances hydraulic conductivity remarkably at relatively loose condition. Biochar amendment also contributes to preventing nitrogen loss and forming more complex bacterial community in soils. The study adds to our knowledge of physio-chemical interactions of biochar with expansive clay, vegetation, water and microorganism.


1994 ◽  
Vol 122 (1) ◽  
pp. 91-105 ◽  
Author(s):  
M. L. Nguyen ◽  
K. M. Goh

SUMMARYA field plot experiment of 271 days duration was conducted on New Zealand irrigated pastures, commencing in the summer (January) 1988, on a Templeton silt loam soil (Udic Ustochrept) by applying 35sulphur (35S)-labelled urine (250 μCi/g S with 1300 μg S/ml) to field plots (600 × 600 mm) at a rate equivalent to that normally occurring in sheep urine patches (150 ml/0·03 m2) to investigate the distribution, transformations and recovery of urinary S in pasture soil–plant systems and sources of plant-available soil S as influenced by the available soil moisture at the time of urine application and varying amounts of applied irrigation water. Results obtained showed that c. 55–90% of 35S-labelled urine was incorporated into soil sulphate (SO42−), ester SO42− and carbon (C)-bonded S fractions within the major plant rooting zone (0–300 mm), as early as 27 days after urine application. Hydriodic acid (Hl)-reducible and C-bonded soil S fractions showed no consistent trend of incorporation. On day 271, labelled-S was found in soil SO42−, Hl-reducible S and C-bonded S fractions to a soil depth of 500 mm, indicating that not only SO42− but also organic S fractions from soils and 35S-labelled urine were leached beyond the major rooting zone. A large proportion (c. 59–75%) of 35S-labelled urine was not recovered in pasture soil–plant systems over a 271-day period, presumably due to leaching losses beyond the 0–300 mm soil depth. This estimated leaching loss was comparable to that (75%) predicted using the S model developed by the New Zealand Ministry of Agriculture. The recovery of urinary S in soil–plant systems over a 271-day period was not affected by different amounts of irrigation water applied 7 days after urine application to soil at either 50 or 75% available water holding capacity (AWHC). However, significantly lower S recovery occurred when urinary S was applied to the soil at 25% AWHC than at field capacity, suggesting that urinary S applied at field capacity might not have sufficient time to be adsorbed by soil particles, enter soil micropores or be immobilized by soil micro-organisms. Both soil ester SO42− and calcium phosphate-extractable soil S in urine-treated soils were found to be major S sources for pasture S uptake. Labelled S from 35S-labelled urine accounted for c. 12–47% of total S in pasture herbage.


Geoderma ◽  
2021 ◽  
Vol 389 ◽  
pp. 114912
Author(s):  
Balin B. Robertson ◽  
Peter C. Almond ◽  
Sam T. Carrick ◽  
Veronica Penny ◽  
Andre Eger ◽  
...  

Author(s):  
MUHAMMAD ASLAM ALI ◽  
SANJIT CHANDRA BARMAN ◽  
MD. ASHRAFUL ISLAM KHAN ◽  
MD. BADIUZZAMAN KHAN ◽  
HAFSA JAHAN HIYA

Climate change and water scarcity may badly affect existing rice production system in Bangladesh. With a view to sustain rice productivity and mitigate yield scaled CH4 emission in the changing climatic conditions, a pot experiment was conducted under different soil water contents, biochar and silicate amendments with inorganic fertilization (NPKS). In this regard, 12 treatments combinations of biochar, silicate and NPKS fertilizer along with continuous standing water (CSW), soil saturation water content and field capacity (100% and 50%) moisture levels were arranged into rice planted potted soils. Gas samples were collected from rice planted pots through Closed Chamber technique and analyzed by Gas Chromatograph. This study revealed that seasonal CH4 emissions were suppressed through integrated biochar and silicate amendments with NPKS fertilizer (50–75% of the recommended doze), while increased rice yield significantly at different soil water contents. Biochar and silicate amendments with NPKS fertilizer (50% of the recommended doze) increased rice grain yield by 10.9%, 18.1%, 13.0% and 14.2%, while decreased seasonal CH4 emissions by 22.8%, 20.9%, 23.3% and 24.3% at continuous standing water level (CSW) (T9), at saturated soil water content (T10), at 100% field capacity soil water content (T11) and at 50% field capacity soil water content (T12), respectively. Soil porosity, soil redox status, SOC and free iron oxide contents were improved with biochar and silicate amendments. Furthermore, rice root oxidation activity (ROA) was found more dominant in water stress condition compared to flooded and saturated soil water contents, which ultimately reduced seasonal CH4 emissions as well as yield scaled CH4 emission. Conclusively, soil amendments with biochar and silicate fertilizer may be a rational practice to reduce the demand for inorganic fertilization and mitigate CH4 emissions during rice cultivation under water stress drought conditions.


2021 ◽  
Author(s):  
Michael Bitterlich ◽  
Richard Pauwels

<p>Hydraulic properties of mycorrhizal soils have rarely been reported and difficulties in directly assigning potential effects to hyphae of arbuscular mycorrhizal fungi (AMF) arise from other consequences of AMF being present, i.e. their influence on growth and water consumption rates of their host plants that both also influence soil hydraulic properties.</p><p>We assumed that the typical nylon meshes used for root-exclusion experiments in mycorrhizal research can provide a dynamic hydraulic barrier. It is expected that the uniform pore size of the rigid meshes causes a sudden hydraulic decoupling of the enmeshed inner volume from the surrounding soil as soon as the mesh pores become air-filled. Growing plants below the soil moisture threshold for hydraulic decoupling would minimize plant-size effects on root-exclusion compartments and allow for a more direct assignment of hyphal presence to modulations in soil hydraulic properties.</p><p>We carried out water retention and hydraulic conductivity measurements with two tensiometers introduced in two different heights in a cylindrical compartment (250 cm³) containing a loamy sand, either with or without the introduction of a 20 µm nylon mesh equidistantly between the tensiometers. Introduction of a mesh reduced hydraulic conductivity across the soil volumes by two orders of magnitude from 471 to 6 µm d<sup>-1</sup> at 20% volumetric water content.</p><p>We grew maize plants inoculated or not with Rhizophagus irregularis in the same soil in pots that contained root-exclusion compartments while maintaining 20% volumetric water content. When hyphae were present in the compartments, water potential and unsaturated hydraulic conductivity increased for a given water content compared to compartments free of hyphae. These differences increased with progressive soil drying.</p><p>We conclude that water extractability from soils distant to roots can be facilitated under dry conditions when AMF hyphae are present.</p><p> </p>


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Sheng-Qiang Shen ◽  
Ming-Li Wei

Hydraulic conductivity of sand-bentonite (SB) backfills amended with polyanionic cellulose (PAC) to lead nitrate (Pb(NO3)2) solutions was evaluated experimentally in this study. PAC-amended sand-bentonite (PSB) backfills were synthesized by mixing sand-bentonite mixture with 0.3 to 1.2% dry PAC (by total dry mixture mass) and mixed with a certain weight of conventional bentonite (CB) slurry. The rheology properties including the filtrate loss, viscosity, density, and pH testes of slurry with various bentonite dosages were measured to determine the reasonable CB dosage of slurry. The slump tests on PSB backfills with various mass slurries were conducted to determine the corresponding water content of backfills with slump 125 ± 5 mm. Under the applied pressure 100 kPa, the hydraulic conductivity to Pb(NO3)2 solutions (kc) of PSB backfills with various PAC contents was evaluated based on the modified filter press (MFP) tests, to ascertain the optimum PAC content of PSB backfills when permeated with Pb(NO3)2 solutions. Index properties, including the specific gravity (Gs) and liquid limit (wL) of PSB backfills, were measured after MFP tests. The MFP tests for PSB backfills were then conducted under various applied pressures to obtain the relationship between void ratio (e) and hydraulic conductivity of backfills. Finally, the flexible-wall permeability test (FWP test) under osmotic pressure 100 kPa was conducted to verify the effectiveness of the MFP test. The results indicate that slurry with 8% bentonite dosage is the reasonable choice in slurry wall construction. PSB has lower GS and higher wL compared to SB; increasing Pb concentration leads to GS of PSB increased and wL of PSB decreased. PSB with 0.6% PAC content is supposed as the optimum proportion of backfills when permeated with concentrated Pb(NO3)2 solution. PAC adsorbs large amount of bound water, which leads to higher water content (w) and e of PSB backfills, while lead ions (Pb) cause the diffuse double layer (DDL) of bentonite compressed and e of PSB backfills reduced. The kc of PSB-0.6 remains lower than 10−9 m/s and increases less than 10 times though the Pb concentration was up to 500 mM, demonstrating that the hydraulic performance of backfills can be improved effectively in Pb(NO3)2 solution by the additive PAC. The comparison results between k from MFP tests and FWP tests show that the MFP test is an effective and easy evaluation of hydraulic conductivity of backfills.


2005 ◽  
Vol 48 (6) ◽  
pp. 863-871 ◽  
Author(s):  
Amauri Nelson Beutler ◽  
José Frederico Centurion ◽  
Alvaro Pires da Silva

The objective of this study was determine the resistance to penetration (PR), least limiting water range (LLWR) and critical bulk density (Db-crit) for soybean yield in a medium-textured oxisol (Haplustox). The treatments represented the soil compaction by passing a tractor over the site 0, 1, 2, 4, and 6 times, with 4 replications in a randomized experimental design. Samples were collected from 0.02-0.05, 0.07-0.10 and 0.15-0.18 m depths. Soybean (Glycine max cv. Embrapa 48) was sowed in December 2002. Plant height, number of pods, aerial dry matter, weight of 100 seeds, and the yield in 3.6 m² plots were recorded. Soybean yield started reduction at the PR of 0.85 MPa and Db of 1.48 Mg m-3. The LLWR was limited in highest part by water content at field capacity (0.01 MPa tension) and in lowest part by water content at PRcrit, achieved the Db-crit to yield at 1.48 Mg m-3.


2011 ◽  
Vol 367 ◽  
pp. 63-71 ◽  
Author(s):  
Adrian O. Eberemu ◽  
Agapitus A. Amadi ◽  
Joseph E. Edeh

Laboratory study on compacted tropical clay treated with up to 16% rice husk ash (RHA), an agro-industrial waste; to evaluate its hydraulic properties and hence its suitability in waste containment systems was carried out. Soil-RHA mixtures were compacted using standard Proctor, West African Standard and modified Proctor efforts at-2, 0, 2 and 4% of optimum moisture content (OMC). Compacted samples were permeated and the hydraulic behaviour of the material was examined considering the effects of moulding water content, water content relative to optimum, dry density and RHA contents. Results showed decreasing hydraulic conductivity with increasing moulding water content and compactive efforts; it also varied greatly between the dry and wet side of optimum decreasing towards the wet side. Hydraulic conductivity generally decreased with increased dry density for all effort. Hydraulic conductivity increased with rice husk ash treatment at the OMC; but were within recommended values of 1 x 10-7 cm/s for up to 8% rice husk ash treatment irrespective of the compactive effort used. This shows the suitability of the material as a hydraulic barrier in waste containment systems for up to 8% rice husk ash treatment and beneficial reuse of this agro-industrial waste product.


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