Low-quality Irrigation Water Research Articles

Drought and Salinity in Citriculture: Optimal Practices to Alleviate Salinity and Water Stress

Among the various abiotic stresses, drought is the major factor limiting crop productivity worldwide. Citrus has been recognized as a fruit tree crop group of great importance to the global agricultural sector since there are 140 citrus-producing countries worldwide. The majority of citrus-producing areas are subjected to dry and hot summer weather, limited availability of water resources with parallel low-quality irrigation water due to increased salinity regimes. Citrus trees are generally classified as “salt-intolerant” with high water needs, especially during summer. Water scarcity negatively affects plant growth and impairs cell metabolism, affecting the overall tree growth and the quality of produced fruit. Key factors that overall attempt to sustain and withstand the negative effect of salinity and drought stress are the extensive use of rootstocks in citriculture as well as the appropriate agronomical and irrigation practices applied. This review paper emphasizes and summarizes the crucial role of the above factors in the sustainability of citriculture.

Institutional framework in relation to the use of low-quality water for food crops irrigation in Tanzania

Institutional framework in relation to the use of low-quality water for food crops irrigation in Tanzania

Effects of deficit irrigation with saline water on wine color and polyphenolic composition of Vitis vinifera L. cv. Monastrell

The Mediterranean climate is characterized by rain scarcity resulting in the frequent use of low quality water for irrigation often containing high concentrations of sulfates and chlorides. This work was undertaken to study the influence of drought and saline irrigation water on the composition of Monastrell wines. The experiment was carried out during three years in a commercial vineyard sited in D.O. Jumilla (SE Spain). Six watering regimes were performed: Rainfed (no irrigation); Control, irrigated throughout the season with good quality water and other four treatments with a combination of two moments of initiation of irrigation (pre- and post-veraison) with two types of salinity water (sulfates and chlorides). The watering regime had more effect on the wine composition than the application of saline irrigation. In general, wines made with grapes from the Rainfed treatment had the highest polyphenols concentration and color intensity. Treatments with post-veraison saline water application improved wine quality with respect to the treatments irrigated during the entire season. Indeed, saline irrigation itself did not influence wine composition, while the watering regime modified wine quality, improving the wine phenolic composition particularly when water is restricted during pre-veraison. In any case, the best wine phenolic and chromatic composition was obtained from the Rainfed vines being the preferred watering management for optimizing wine quality. If saline irrigation has to be applied to improve vine performance, it is preferred to concentrate its application during the post-veraison period.

Spatial Relationship between Irrigation Water Salinity, Waterlogging, and Cropland Degradation in the Arid and Semi-Arid Environments

Water scarcity in arid and semiarid regions has resulted in using of low-quality waters for crop irrigation. This study aims to investigate the spatial relationship of low-quality irrigation water and waterlogging in arid and semiarid environments. The multi-decadal (1990–2020) time series Landsat images and hadrochemical water analysis were employed within geographical information system mapping (GIS) to understand the relationship between irrigation water, soil salinity, and waterlogging in the western Nile Delta, Egypt. The normalized difference water index (NDWI) and the normalized difference vegetation index (NDVI) from the Landsat images were combined to quantify the Spatiotemporal changes in the croplands and waterlogging from 1990 to 2020. ArcGIS inverse distance weighted (IDW) interpolation was used to create spatial layers of irrigation water salinity from electrical conductivity (EC), sodium adsorption ratio (SAR), and soluble sodium percentage (Na%). The results demonstrated a significant spatial relationship between waterlogging and EC, SAR, and Na% in irrigation groundwater. Long-term irrigation with high salinity groundwater led to increased soil salinity, low soil permeability, and waterlogging. This study offers a time- and cost-efficient geospatial method for regional monitoring of surface waterlogging and mitigation strategies for cropland degradation and agricultural drainage water recycling that would benefit stakeholders and decision-makers.

The Integration of Multivariate Statistical Approaches, Hyperspectral Reflectance, and Data-Driven Modeling for Assessing the Quality and Suitability of Groundwater for Irrigation

Sustainable agriculture in arid regions necessitates that the quality of groundwater be carefully monitored; otherwise, low-quality irrigation water may cause soil degradation and negatively impact crop productivity. This study aimed to evaluate the quality of groundwater samples collected from the wells in the quaternary aquifer, which are located in the Western Desert (WD) and the Central Nile Delta (CND), by integrating a multivariate analysis, proximal remote sensing data, and data-driven modeling (adaptive neuro-fuzzy inference system (ANFIS) and support vector machine regression (SVMR)). Data on the physiochemical parameters were subjected to multivariate analysis to ease the interpretation of groundwater quality. Then, six irrigation water quality indices (IWQIs) were calculated, and the original spectral reflectance (OSR) of groundwater samples were collected in the 302–1148 nm range, with the optimal spectral wavelength intervals corresponding to each of the six IWQIs determined through correlation coefficients (r). Finally, the performance of both the ANFIS and SVMR models for evaluating the IWQIs was investigated based on effective spectral reflectance bands. From the multivariate analysis, it was concluded that the combination of factor analysis and principal component analysis was found to be advantageous to examining and interpreting the behavior of groundwater quality in both regions, as well as predicting the variables that may impact groundwater quality by illuminating the relationship between physiochemical parameters and the factors or components of both analyses. The analysis of the six IWQIs revealed that the majority of groundwater samples from the CND were highly suitable for irrigation purposes, whereas most of the groundwater from the WD can be used with some limitations to avoid salinity and alkalinity issues in the long term. The high r values between the six IWQIs and OSR were located at wavelength intervals of 302–318, 358–900, and 1074–1148 nm, and the peak value of r for these was relatively flat. Finally, the ANFIS and SVMR both obtained satisfactory degrees of model accuracy for evaluating the IWQIs, but the ANFIS model (R2 = 0.74–1.0) was superior to the SVMR (R2 = 0.01–0.88) in both the training and testing series. Finally, the multivariate analysis was able to easily interpret groundwater quality and ground-based remote sensing on the basis of spectral reflectance bands via the ANFIS model, which could be used as a fast and low-cost onsite tool to estimate the IWQIs of groundwater.

Impacts of Magnetic Field Treatment on Water Quality for Irrigation, Soil Properties and Maize Yield.

Application of magnetic treatment technology for saline irrigation water in agriculture is very limited. Therefore, field experiment was conducted to investigate the influence of magnetic field treatment on the quality of saline groundwater for irrigation and in turn impacts of irrigation by magnetized water on sandy soil properties and maize production under desert conditions in Sinai, Egypt. Magnetic field treatment of irrigation water caused leaching salts below root zones, reduced sodium and chloride accumulation, decreased Na/Cl ratio from 1.01 to 0.89 which mitigated the negative impacts on maize plants in the root zone. Results showed high significant decreases in soil salinity (EC, and SAR) and levels of soil soluble cations and anions in the root zone of soils irrigated with magnetically treated saline water compared to control. Also, sandy soil irrigated with magnetized water had a higher moisture content, available water and soil field capacity compared to control. Irrigation with unmagnetized water induced wetted soil volume of 2575.68 cm3 reflecting low drip irrigation application efficiency of 64.07 %, while wetted soil volume was 2919.24 cm3 reflecting high water application efficiency of 72.62% for irrigation with magnetized water. Results of this research demonstrated significant beneficial effects of magnetic field treatment on saline water quality, sandy soil properties and maize crop yield confirming the possibility of using low quality water for irrigation under water scarcity and arid conditions.

Effect of contamination sources on the rate of zinc, copper and nickel release from various soil ecosystems

Background and objectiveSoil is a substantive component in biosphere habitually endangered to superfluity contaminants particularly potential toxic elements (PTEs). The source of soil contaminants is very critical in controlling both their release and expected hazards in the different soil ecosystems. This study aims to investigate the effect of low-quality irrigation water (LQW) on the extent of soil pollution through desorption of zinc (Zn), nickel (Ni) and copper (Cu) from different polluted soils, collected from LQW irrigated farms for more than 40–80 years at Giza and Kafr-Elsheikh Governorates, Egypt.ResultsModels incorporated modified Freundlich (MFE), Elovich, first order and parabolic diffusion (PDE) showed significant results in describing the kinetic data under Egyptian conditions. Results entailed that according to the coefficient of determination (R2) and standard error, all used models well described the desorption of Cu, Ni and Zn, the most prevalent contaminants in the trailed soil ecosystems; for example, the R2 values were higher than 0.96** for zinc desorption using MFE model. As far as the PTEs levels are considered, the highest contaminant desorption rates were recorded at Kafr-Elsheikh site, followed by Kombora, and the lowest ones were in Abo Rawash soil ecosystem. The succession of more than one model to describe the kinetic perspective confirmed that the different mechanisms take place in PTEs sorption, distribution and subsequently release from different soil ecosystems.ConclusionsThe numerical values indicated that the soil ecosystems contaminated with industrial effluents were higher than those irrigated with sewage effluents regardless of the type of land use. More attention should be paid to low-quality water application in agriculture irrigation and its environmental risks.

Systematic review: Effect of Irrigation Water Quality and Deficit Irrigation on Crop Yield and Water Use efficiency

The main purpose of this paper is to review on the effect of irrigation water quality and deficit irrigation on crop yield and water use efficiency. Low quality water for irrigation can impose a major environmental constraint to crop productivity. If salts become excessive, losses in yield will result. To prevent yield loss, salts in the soil must be controlled at a concentration below that which might affect yield. Irrigation application below the full evapotranspiration requirement is termed as deficit irrigation. Deficit irrigation consists of deliberately applying irrigation water in amounts below the plant‘s water requirements. Deficit irrigation can be applied at certain periods during the crop‘s growing season or throughout its growing season. Yield reductions also occur in a number of crops when subjected to water stress. Yield reductions depend on the crop‘s sensitivity to water stress at its various growth stages. In order for deficit irrigation to be an economically viable practice, the revenue lost due to yield reduction should be lower than savings in total cost of production. The goal of deficit irrigation is to increase crop water use efficiency by reducing the amount of water that is applied or by reducing the number of irrigation events. The interaction effects of water quality and DI illustrated that when the two types of stresses; saline and DI were coupled together, a serious reduction occurred on total dry biomass and total yield. The interaction effects of water quality and deficit irrigation illustrated that when the two types of stresses; saline and deficit irrigation were coupled together, a serious reduction occurred on total dry biomass and total yields.

Assessment of soil response to exchangeable sodium percentage by consistence and water retention properties

The use of low-quality water for irrigation is expected to keep increasing worldwide, which increases the risk of soil degradation. The response of soil to irrigation waters with excessive sodium depends on the soil clay behavior. Soil physical properties that can distinguish smectitic soils from non-smectitic soils could identify soils that are sensitive to exchangeable sodium. This study explores the use of Atterberg limits, coefficient of linear extensibility (COLE) and soil water retention as possible properties to determine if a soil is sensitive to exchangeable sodium. Soils used were synthetic soils prepared from mixtures of silt and clay minerals, and six natural soils. Atterberg limits, COLE and soil water retention was measured at ESP values of 0, 50 and 100% on these soils. Multiple linear regression functions were developed to predict soil liquid limit, plasticity index, COLE, and soil water retention at −336 cm H2O. The liquid limit, and COLE increased as the amount of sodium-saturated smectite increased in the synthetic soils. The liquid limit, COLE and water retention at matric potentials greater than −336 cm of H2O increased on smectite clay dominant soils when elevated ESP was combined with low salinity. The liquid limit increased from 49 to 67 on average and −336 H2O water content increased from 38 to 70% on average between 0 and 100% ESP treatments on the four smectitic soils. On a kaolinitic soil liquid limit decreased from 56.1 to 51.8 and −336 H2O water content increased from 33.7 to 35.9% between the ESP 0 and 100% treatment. Liquid limit increased from 188 to 679 and COLE increased from 0.47 to 1.19 mm mm−1 between calcium smectite (fullers earth) and sodium smectite (Wyoming bentonite), whereas liquid limit decreased from 56 to 39 and COLE decreased from 0.195 to 0.104 mm mm−1 between calcium and sodium saturated kaolinite. Plasticity index increased by 75% between the ESP 0 and ESP 100 treatments on the smectitic soils, whereas there was a 260% increase in plasticity index between fullers earth and bentonite. The root mean squared error that liquid limit could be predicted with was 3.3 plastic limit was 2.4, COLE was 0.036 mm mm−1, and 1/3rd bar water content was 2.2 × 10−3 g g−1. Smectitic soils had increases in soil swelling related properties, whereas non-smectitic clay soils had no changes in swelling related properties from ESP. Liquid limit and water retention at water potentials of −1/10th and −1/3rd bar were the properties that best distinguished soils that respond to ESP from soils that do not respond to ESP. Soil consistence properties and water retention can determine soils that contain smectite clay which is the clay mineral that is most sensitive to soil ESP.

The grapevine NaE sodium exclusion locus encodes sodium transporters with diverse transport properties and localisation

Grapevine (Vitis vinifera L.) is a valuable crop for human consumption and wine production, and is prone to suffering from salinity stress in arid regions or when exposed to low quality irrigation water. A previous study identified a quantitative trait locus (QTL) NaE, containing six High-affinity Potassium Transporter 1 genes, that was associated with shoot Na+ exclusion in grapevine. While HKT1;1 was predicted to be the most likely gene within this QTL to encode for this important salinity tolerance sub-trait, four other HKTs within the QTL remained uncharacterised; VviHKT1;2 encodes a truncated transcript unlikely to form a functional transporter. In this study, two allelic variants for each of VviHKT1;6, VviHKT1;7 and VviHKT1;8 from the heterozygous grapevine variety Cabernet Sauvignon were functionally characterised. Using the Xenopus laevis oocyte heterologous expression system, as well as transient expression in tobacco leaves, we found that the VviHKT1;6 and VviHKT1;7 alleles encoded plasma membrane localised proteins that facilitated significant non-rectifying Na+ transport. Conversely, proteins encoded by the VviHKT1;8 alleles were inwardly-rectifying, weak Na+ transporters that localised to intracellular organelles. Mining of previous RNA-seq gene expression data suggested that VviHKT1;6–8 are weakly expressed in grapevine roots, flower buds, and seeds under normal conditions and different nutrient regimes. We propose that VviHKT1;6 and VviHKT1;7 are likely to have a less significant role in grapevine leaf Na+ exclusion than VviHKT1;1, and that VviHKT1;8 is involved in endomembrane Na+ transport.

The validity of carbon isotope discrimination as a screening criterion for grain yield in two barley landraces under deficit irrigation with saline water in southern Tunisia.

Arid and semiarid regions with rain shortage and scarce good quality water must make use of low-quality water for irrigation. Consequently, improved plant cultivars for use in these areas should show adaptation capacities to confer drought and salt resistance and allow the cultivation under limited water availabiltiy. The present study was conducted to determine the effect of deficit irrigation with saline water on two local barley landraces, "Karkeni" and "Bengardeni". Plants were saline-irrigated with three watering regimes during tillering, heading, and grain filling stages. Biochemical traits, carbon isotope discrimination (Δ13C), mineral composition, grain yield (GY) and water use efficiency based on grain yield (WUEgy) were evaluated as performance indicators. Almost all of the studied traits (e.g. soluble carbohydrates, proline, ∆13C, Na concentration, and GY) were significantly affected by deficient saline-irrigation regimes at different growth stages. The hierarchical clustering analysis clearly showed that Δ13C placed very close to GY averaging two barley landraces, which was in accordance with the scatter plot result. Multiple linear regression performed between GY as the dependent variable and other traits studied as the independent variables indicated that WUEgy, Δ13C, and soluble carbohydrates significantly explained the variability in GY (R 2=95.64%). A significant positive correlation that observed between ∆13C and GY at three growth stages, indicated that ∆13C may be an important proxy component for indirect selection of yield potential in barley under deficient irrigation regimes with saline water. According to our result, "Karkeni" seems to be more efficient in terms of higher GY, WUEgy, proline and carbohydrate contents, K, Mg and Zn concentrations, as well as lower Δ13C and lipid peroxidation as compared with "Bengardeni", under low osmotic potential imposed by deficient irrigation treatments with saline water, "Karkeni" can thus be selected and used as a parent in order to obtain more tolerant plants against such stresses in future breeding programs.

EMERGENCE, GROWTH, AND PRODUCTION OF COLORED COTTON SUBJECTED TO SALT STRESS AND ORGANIC FERTILIZATION

ABSTRACT The semi-arid region of Northeast Brazil is vulnerable to problems of water scarcity and salinity, resulting in low-quality irrigation water and the need to adopt cultivation strategies that make the production system viable. Given the above, this study aimed to evaluate emergence, growth, and production of colored cotton subjected to increasing levels of irrigation water salinity and organic matter doses. The experiment was carried out in a eutrophic Regolithic Neosol with a sandy loam texture in a greenhouse in the municipality of Campina Grande - PB, Brazil. A randomized block design was used in a 4 x 4 factorial scheme with three replicates, and the treatments corresponded to four levels of electrical conductivity of water - ECw (1.7, 3.4, 5.1, and 6.8 dS m-1) and four doses of organic matter - OM (0, 2.5, 3.5, and 4.5% based on soil volume). Increasing irrigation water salinity with ECw values above 1.7 dS m-1 reduced emergence, growth, and production of colored cotton, and the cotton seed weight was the variable most affected by salinity. Organic matter addition led to increased cotton growth and production, especially in terms of seed weight. Increasing doses of organic matter attenuated the effect of irrigation water salinity on the number of bolls in ‘BRS Jady’ cotton.

A Tool for the Evaluation of Irrigation Water Quality in the Arid and Semi-Arid Regions

In the Mediterranean arid and semi-arid regions, large amounts of low quality waters could be used for crop irrigation, but the adoption of articulated classifications with too rigid quality limits can often reduce the recoverable quantities of water and make the monitoring of water quality too much expensive. Therefore, an evaluation of irrigation water quality based on only a few crucial parameters, which consider the crop species to be irrigated and the type of irrigation system and management adopted, can be an easy and flexible method for maximizing the reuse of wastewater and low-quality water for agricultural purposes. In this view, an irrigation water quality tool (IWQT) was developed to support farmers of arid and semi-arid regions on evaluating the use of low quality water for crop irrigation. The most significant and cheapest parameters of irrigation water quality were identified and clustered in three quality classes according to their effects on crop yield and soil fertility (agronomic quality indicators), human health (hygiene and health quality indicators), and irrigation systems (management quality indicators). According to IWQT parameters, a tool reporting a series of recommendations, including water treatment types, was implemented to guide farmers on the use of low quality irrigation water.

Irrigation water quality and the threat it poses to crop production: evaluating the status of the Crocodile (West) and Marico catchments, South Africa.

Ensuring food security is becoming increasingly difficult due to limited freshwater resources. Low-quality irrigation water also poses a severe threat to crop yield and quality. The aim of this study was to evaluate the water quality associated with the Crocodile (West) and Marico catchments, which represent one of South Africa's most developed regions. Sources of irrigation water include the hypertrophic Hartbeespoort Dam, as well as the heavily impacted Crocodile (West) River. Analysis of historical irrigation water quality data (from January 2005 to December 2015) revealed that the Hartbeespoort and Crocodile (West) irrigation schemes were exposed to calcium sulfate enrichment, likely as a result of extensive mining activities in the Bushveld Igneous Complex. Also, significant differences in water quality parameters occurred between these irrigation schemes and the reference system (Marico-Bosveld Irrigation Scheme), while important salt (chloride and sodium) and nutrient (inorganic nitrogen and orthophosphate (as phosphorus)) concentrations exceeded threshold values provided by irrigation water quality guidelines. The Hartbeespoort and Crocodile (West) irrigation schemes also presented distinctive temporal (long-term and seasonal) patterns in water quality. Seasonal variation in pH levels at the Hartbeespoort Irrigation Scheme is likely caused by excessive algae growth and cyanobacteria blooms (Mycrocystis sp.), which also pose an important threat to human and animal health. Despite mitigation efforts by government and other stakeholders, some of South Africa's major irrigation schemes remain highly impacted as a result of water quality deterioration.

Improvement of Supplementary Irrigation Water Quality for Rain-Fed Agriculture in the Semi-Arid Region Using Magnetization Techniques

Rain-fed agriculture depends on the groundwater as a supplementary source of irrigation. The poor quality of water from the hard rock area is applied to the crops to save the crop. Continuous irrigation leads to degradation of soil, drip irrigation system as well plants. This study assessed the damages on the drip irrigation system and soil, inflicted by the use of low-quality irrigation water. The quality of water was improved with reference to raw water in terms of pH (1.57% - 5.88%), EC (3.08% - 10.08%), ions (0.96% - 46%) by using magnetization method, without disrupting the existing irrigation system in the basaltic aquifer in semi-arid to the arid condition. This was demonstrated before the farmers in central India.

Effects of arbuscular mycorrhizal fungi on the growth of two turfgrasses grown under greenhouse conditions

ABSTRACT The need for salinity resistance in turfgrass is increasing because of the enhanced use of effluent and other low-quality water for turfgrass irrigation. Although most turfgrasses form an arbuscular mycorrhizal fungus (AMF) symbiosis, there is little information on the mycorrhization of turfgrass species. Therefore, the aim of this study was to determine the effects of three AMF species, Glomus intraradices Schenck & Smith, Glomus etunicatum Becker & Gerdemann, and Glomus deserticola Trappe & John, and a mixture thereof on the growth, productivity, and nutrient uptake of two species of cool-season turfgrasses, Challenger Kentucky bluegrass (Poa pratensis L.) and Arid tall fescue (Festuca arundinacea Schreb.), and to relate the effects to colonization of the roots by mycorrhiza to assess the dependency of the plants (mycorrhizal dependency [MD]). Following the experimental period (4 months) and measurements, the mycorrhizal inoculated plants had significantly greater biomass production compared to that of non-inoculated plants. MD and shoot mineral contents (particularly P) differed among turfgrass hosting AMF, and the highest value (13%) occurred for P. pratensis and F. arundinacea seedlings colonized with G. intraradices and G. deserticola, respectively. The P content was highest for the F. arundinacea/mixed AMF combination compared to other treatments. We confirmed that mycorrhizal inoculation (P. pratensis/G. intraradices and F. arundinacea/mixed AMF combinations) enhanced plant productivity and nutrient uptake (especially P) even under non-optimum conditions.

Obstacles to Low Quality Water Irrigation of Food Crops in Morogoro, Tanzania

Knowledge on users’ and regulators’ views regarding obstacles on the use of low quality water forms the basis for the improvement of water reuse in food crops irrigation. A qualitative study was conducted to assess the obstacles to the use of low quality water for irrigation of food crops in urban and peri-urban areas in Tanzania. The study considered Morogoro urban and peri-urban areas as a case study due to the existence of paddy and vegetable production using the effluent from the waste stabilisation ponds. Both primary and secondary data were used. Primary data were collected through in-depth interviews with 22 key informants, and 4 focus group discussions with farmers. Content analysis was used in this study. Findings show that domestic wastewater was poorly disposed, waste stabilisation ponds as treatment facilities had limited management, and quality monitoring of effluent from the waste stabilisation ponds was limited to permit safe use of the effluent in food crops irrigation. The government officials were of the view that the effluent from the waste stabilisation ponds should not be used for leafy vegetables irrigation while farmers viewed vegetables farming as a quick source of income and livelihood strategy for many years. The study therefore suggests that the relevant agencies should improve the treatment of wastewater and quality monitoring of the effluent for safe use of low quality water for food crops irrigation in urban and peri-urban areas.

Biochar-based nursery substrates: The effect of peat substitution on reduced salinity

The growing of ornamental plants for urban greening has significant environmental and economic implications. In particular, the intensive use of peat and high-quality water at the nursery stage is sensitive due to the problems of soil depletion and water salinization even in urban areas. In these contexts, a preference for salinity-resistant species and cultivation techniques based on the substitution of low-impact materials could be beneficial.Here, an experiment has been carried out with two ornamental plant species – cherry laurel [Prunus laurocerasus L.] which is salinity-sensitive, and phillyrea [Phillyrea latifolia L.] which is salinity-resistant – using substrates containing different amounts of biochar in place of peat. Moreover, using irrigation water at two different salinity concentrations, we assess the extent to which the biochar can mitigate salinity damage in these plant species. The results of this study showed that the addition of biochar to the potting medium had no effect on plant growth but crucially limited cherry laurel salinity damage. Tolerance to salinity was attributed to lower Na+ retention in the biochar-containing substrates. Based on these findings, we conclude that the application of biochar not only reduces the amount of peat required in growth substrates, but can also permit the utilization of low-quality irrigation water – thereby also reducing the leaching of nutrients such as K+ and N-NH4+.

English

Low quality water has become valuable resource with restricted or unrestricted use in food production depending on its quality. This study has quantified the occurrence of Escherichia coli in Brassica rapa L. chinensis (Chinese cabbage) vegetables and low quality irrigation water. A total of 106 samples including Chinese cabbage (69) and water (37) were collected. The E. coli were cultured in petri film selective E. coli plates at 44°C. The Chinese cabbage irrigated with river water at Fungafunga area indicated significantly (P<0.001) high prevalence 86% (n=21, 0.00-4.10 log cfu/g) of E. coli than those irrigated with treated wastewater at Mazimbu 10% (n=48, 0.00-1.36 log cfu/g). The mean counts of E. coli in untreated wastewater ranged from 4.59 to 5.56 log cfu/mL, while in treated wastewater was from 0.54 to 1.05 log cfu/mL and in river water it was 2.40 log cfu/mL. Treated wastewater of the quality found in this study could be used for food production. Key words: Agricultural irrigation, Chinese cabbage, incidental inputs, river water, wastewater.

Effects of magnetized water application on soil and maize growth indices under different amounts of salt in the water

Application of low quality water for irrigation is compulsive in facing water scarcity. Use of a magnetic field is an approach to overcome this challenge. This study examined the impact of magnetic field technology on improving germination under water of different salinity levels. An experiment was conducted to determine the effects of saline water levels, i.e. (S1):0.5, (S2):2, (S3):4 and (S4):6 dS/m combined with magnetized technology (with or without) on maize growth. Thus, magnetic treatment was applied by passing the irrigation water through a 1,500 mT magnetic field at 3 litres per minute (lpm) flow rate. Some emergence indices, such as emergence index, emergence rate index (ERI) and mean emergence time, were used to evaluate the germination of maize seed. As for soil properties after plant harvest, the use of magnetically treated irrigation water reduced soil pH but increased soil electrical conductivity and available N and P. ERI increased from 7.6 to 10.2, 9.1 to 11.1, 10.3 to 13.3, and 11.8 to 13.3 when applying the magnetized field for S1, S2, S3 and S4, respectively. Overall, the growth parameters of maize were improved by using magnetic technology with saline water, while the opposite trend was shown for increasing salinity without magnetic treatment.