Soil Electrical Conductivity Values Research Articles

Effects of Soil Salinity on the Roadside Herbaceous Plant Community in a Non-Forest Coastal Area of Bangladesh

The gradual increase of salinity in the coastal areas of Bangladesh instigates several challenges for normal plant growth. The responses of forest communities to the rise of salinity are somehow documented. However, the adjustments of non-forest plant communities against salinity are still limited in the literature. This study reports the abundance and species richness of herbaceous plant population along with the soil salinity gradients in a coastal area of Bangladesh. Twenty-five roadside quadrants were systematically selected and studied for herbaceous plant diversity and soil properties. Soil Electrical conductivity (EC) and moisture show a generally rising trend from the north to the south. Moreover, the quadrants closer to the river or aquaculture with low elevation represents the salinity hot spots. About 1116 herbaceous plants belonging to 11 species were recorded. Croton bonplandianum baill is the dominant species and showed higher adaption capacity against soil EC values. Four out of 25 quadrants with higher EC, moisture, and lower elevation recorded no plants. The herbaceous plant biodiversity reveals a strong spatial pattern and tendency to shrink with the rise of soil salinity while progressing towards the south-east direction. The area is evident in the contagious distribution of plant species and accommodates four dominant clusters. Overall, the study outcomes improve our understanding of the impact of environmental stressors on the distribution of herbaceous plants in the coastal area.

Reduction of salinity and sodicity of saline-sodic soils under filed condition in Brazilian semi-arid region

The salinization process in irrigated areas in the semi-arid region of Brazil, constantly cause economic, social, and environmental problems. Therefore, the present research aimed at assessing the effect of different amounts of agricultural gypsum and cow manure associated with an artificial drainage system and salt leaching due to the application of amount of water in a saline-sodic soil under field condition. The experiment was carried out at the irrigated perimeter of Jacaré-Curituba, Poço Redondo, with an experimental design split into plots made of doses of gypsum corresponding to 0,0; 4,300.00 and 8,600.00 kg.ha-1 combined with and without organic matter, cow manure with 25,000.00 kg.ha-1 and 0.00 kg.ha-1. Each treatment (six in total) was repeated four times. Thus, 24 plots of 50 m2 were monitored (split plot) with an area of 1.200 m2. All treatments had an artificial drainage system in the center of the plot and the same amount of leach water was then added. The outcomes allowed us to understand that all treatments had the salinity and sodicity soil values reduced at the studied site. Moreover, the treatments with cow manure (source of organic matter) presented the best results, because soil electrical conductivity values (< 4 dS m-1) reached the normal level to agricultural yield.

Saline groundwater in the Buffels River catchment, Namaqualand, South Africa: A new look at an old problem

Namaqualand, South Africa, is a global biodiversity hotspot but local populations are affected by challenging economic conditions largely because of poor access to water. In this study groundwater types are characterised and sources of salts and salinisation processes are identified using hydrochemistry and δ18O, δ2H and 87Sr/86Sr data. Analysis of δ18O and δ2H data suggests that evaporation does not play a major role in salinisation of the groundwater. However, major ion chemistry and 87Sr/86Sr ratios indicate that salts present in the groundwater are linked to dry deposition of marine aerosols and ion-exchange reactions in soils in the alluvial aquifer systems. The hydrochemical variability of the groundwater in the basement aquifer system suggests that there are strong local controls linked to weathering processes in individual basement rock types. The region is also notable for the high density of heuweltjies, biophysical features associated with increased nutrient levels, associated with termite activity. Electromagnetic scanning as well as measurement of water-soluble soil electrical conductivity values on and off heuweltjies, show that heuweltjies are saline with salinity increasing with depth. The level of groundwater salinity correlates with the level of heuweltjie salinity. Precipitation records from the last 150 years provide support for the hypothesis that accumulated salts, and in particular, heuweltjie salts are flushed into the groundwater system during sporadic large volume precipitation events. Thus, heuweltjies and hence termite activity, could potentially represent a previously unrecognized contributor to groundwater salinisation across Namaqualand and in other parts of the world.

Assessment of physiochemical properties and concentration of heavy metals in agricultural soils fertilized with chemical fertilizers

The present study aim to assess the effect of phosphate and urea fertilizers on the physicochemical properties, pH and electrical conductivity (EC) of the soil. The effect of these fertilizers on cation exchange capacity (CEC), organic matter (OM), and the possibility of contamination with heavy metals (HM) (Cr, Cu, Cd, Mn, Zn, Ni, Fe, and Pb) were studied on the soils of Alshati agricultural project at different seasons after forty years of fertilization. Uncultivated soil samples were also analyzed for comparison and considered as reference. Mean values of soil pH, EC, CEC, and OM ranged between 6.88-7.32, 0.14–0.26 μS/cm, 2.95–4.19 Cmol/kg and 0.49–0.53%, respectively, in all seasons. Concentrations of HMs were 9.50–38.38, 0.0–2.05, 0.0–0.47, 0.0–29.81, 0.0–13.85, 2.83–25.95 and 104–512.20 mg/kg respectively, for Cr, Cu, Cd, Mn, Zn, Ni and Fe. The concentrations of the HMs in the soil were found to be vary significantly with the seasons (winter, spring, summer, and autumn). However, no traces of Pb was found in the soil samples. The result showed a significant correlation between, pH, EC, CEC, OM and HM content of the soil. The geochemical index of contamination shows that there was no contamination with Cu, Cd, Zn, Pb, Cr, Mn, Ni, and Fe.

Farklı Buğday Çeşitlerinde Bitki Büyüme İndisi İle Toprak Elektriksel İletkenlik Değerleri Arasındaki İlişki

Araştırma, Ankara Üniversitesine bağlı Haymana Araştırma ve Uygulama çiftliğinde gerçekleştirilmiştir. Çalışmada üç farklı buğday çeşidi (Kırgız-95, Kırkpınar-79, Svevo) kullanılmıştır. Araştırmanın amacı toprağın elektriksel iletkenlik değerleri (EC, mS m-1) ile bitki büyüme indisi (BBİ) veya NDVI olarak tanımlanan parametrelerin belirlenerek, bu parametreler arasındaki ilişkinin belirlenmesidir. Araştırmada; EM38, elektriksel iletkenlik sensörü ve GreenSeeker (bitki büyüme indisi tespit sensörü) kullanılmıştır. Elde edilen değerler istatistiksel olarak değerlendirilerek (regresyon analizi) iki parametre arasındaki ilişki belirlenmiştir. Araştırma sonucunda, toprağın elektriksel iletkenlik değerleri ile bitki büyüme indis değerleri arasındaki ilişkiler negatif yönde (R2) sırasıyla Kırgız-95 çeşidi için 0,7718, Kırkpınar-79 çeşidi için 0,7675 ve Svevo çeşidi için 0,7807 olarak bulunmuştur.

Acceleration of soil salinity accumulation and soil degradation due to greenhouse cultivation: a survey of farmers' practices in China.

Soil environment and water quality face large pressure due to the rapid expansion of greenhouse cultivation in China. However, studies rarely provide the linkage between farmers' practices and soil degradation in greenhouse cultivation field. In this study, a field survey and sampling of greenhouse cultivation soil were conducted in five regions of China to investigate the accumulation and variation characteristics of soil ion compositions in the field. First, the pH, ion compositions, and electrical conductivity (EC) of 132 composite soil samples were analyzed. Second, farmers' practices with regard to fertilizer, crop yield, and soil degradation processes were surveyed. Lastly, soil nutrient status was evaluated by different grades, and the principal component analysis method was used to analyze the main sources of soil ion compositions. Results of the study reveal the following: (1) Enrichment of greenhouse soil nutrient was mainly caused by excessive fertilization, which introduced the secondary salinization phenomenon for 3-5 years in plastic greenhouse and 1-3 years in multispan greenhouse. (2) Significant changes between the EC and salt ion composition of open soil and greenhouse cultivated soil were observed. The contents of nitrate nitrogen and ammonium nitrogen in the greenhouse soil were high. (3) After a certain period of cultivation in the greenhouse, salt accumulation, pH decline, and varying degrees of acidification were observed in the soil profile. The relationship between soil pH and EC values indicated that the balance of soil compositions was broken. The recommended methods for sustaining greenhouse cultivation include balanced fertilization, rotation practices, and reasonable water utilization in the field.

Characteristics of soil water and salt associated with Tamarix ramosissima communities during normal and dry periods in a semi-arid saline environment

Tamarisk (Tamarix ramosissima) plants are widely distributed in semi-arid regions with saline soils. In these environments, the survival and sustainability of the Tamarisk plants are critically related to the availability and distribution of soil water and salt. In this study, we analyzed the soil water content (SWC) and soil electrical conductivity (EC) to the depth of 60 cm in natural Tamarisk communities, located in a semi-arid saline region of northwestern China, in July 2016 (a normal period) and July 2017 (a dry period). The results showed that SWC varied from 1.91 to 7.82% and soil EC ranged from 9.65 to 25.38 mS/cm in the 0–60 cm soil layer. Despite the deficiency of precipitation in the study period of 2017, the SWC in all plots was higher at the 20–60 cm depth than that of the normal study period in 2016. Compared to 2016, the soil was also less saline in 2017, representatively by lower soil EC values at the 0–40 cm depth. Additionally, the SWC decreased with Tamarisk density, indicating that Tamarisk plants increase water consumption. The SWC and soil EC both revealed “island” distribution, with highest level found inside or underneath the Tamarisk plant canopies. Both the SWC and soil EC presented a strong or moderate spatial dependency, and the spatial dependency in soil EC were significantly affected by community composition. Correlations (Pearson’s r) showed that there were positive correlations between SWC and soil EC. The results above indicate that Tamarisk communities can ameliorate the semi-arid high saline soil environment, and that the growth and distribution of Tamarisk plants influence the spatiotemporal variability of SWC and soil EC. In addition, the results also demonstrate that the possible appropriate density in the process of constructing Tamarisk plants should be considered in order to achieve the optimal water condition. The study may provide a scientific basis for the ecological restoration and halophytes establishment in the semi-arid saline region of northwestern China and other areas with similar ecologies.

Comparison of Soil EC Values from Methods Based on 1:1 and 1:5 Soil to Water Ratios and ECe from Saturated Paste Extract Based Method

The present study investigates the effect of three different methods of obtaining 1:1 and 1:5 soil-over-water mass ratios (soil:water) extracts for soil electrical conductivity (EC) measurements (EC1:1, EC1:5). On the same soil samples, also the electrical conductivity of the saturated paste extract (ECe) was determined and the relationships between ECe and each of the three of EC1:1 and EC1:5 values were examined. The soil samples used were collected from three areas over Greece (Laconia, Argolida and Kos) and had ECe values ranging from 0.611 to 25.9 dS m−1. From the results, it was shown that for soils with ECe < 3 dS m−1 the higher EC values were obtained by the method where the suspension remained at rest for 23 hours and then shaken mechanically for 1 h. On the contrary, no differences were observed among the three methods for soils with ECe > 3 dS m−1. Also, in the case of EC1:5, the optimal times for equilibration were much longer when ECe < 3 dS m−1. Across all soils, the relationships between ECe and each of three methods of obtaining EC1:1 and EC1:5 were strongly linear (0.953 < R2 < 0.991 and 0.63 < RMSE < 1.27 dS m−1). Taking into account the threshold of ECe = 3 dS m−1, different ECe = f(EC1:5) linear relationships were obtained. Although the linear model gave high values of R2 and RMSE for ECe < 3 dS m−1, the quadratic model resulted in better R2 and RMSE values for all methods examined. Correspondingly, in the 1:1 method, two of the three methods used exhibited similar slope values of the linear relationships independent of ECe value (ECe < 3 or ECe > 3 dS m−1), while one method (23 h rest and then shaken mechanically for 1 hour) showed significant differences in the slopes of the linear relationships between the two ranges of ECe.

ON‐FARM WATER AND SALT MANAGEMENT UNDER A STRAWBERRY–PEPPER COMBINATION IN THE KORBA AREA

AbstractIn the irrigated area of Korba, aquifer high electrical conductivity exceeding 28 dS m‾¹ was measured. Increasing soil electrical conductivity has led to an abandonment of farms and a reduction of the area devoted to some crops, such as tomatoes, which fell from 450 to 210 ha, between 1998 and 2011. Some new practices such water blending, crop rotation and crop association have been introduced. The most important crop combination of strawberry–pepper is widespread throughout the area. The two crops were grown simultaneously in the same plots for two successive years during the first years of the project; this new combination reached 130 ha. During recent years, this combination has been maintained for only one year due to the observed yield decrease during the second year. In order to evaluate this crop combination and with the aim of understanding why farmers grow only one year of this combination, trials were conducted from July 2011 to August 2013. Soil electrical conductivity (EC) distribution and irrigation uniformity were analysed. During irrigation seasons, soil EC was 1.45 dS m‾¹ at the beginning (July 2011) and reached 3.3 and 5.52 dS m‾¹ respectively in August 2012 and August 2013. These soil EC values were high for strawberry. This explains why farmers choose rainfed crops, and salt‐tolerant crops during the second year. A survey concerning irrigation uniformity gave an acceptable figure of almost 90%. Even if the gross margin shows that it is not worthwhile to blend fresh and saline water, farmers opt for water blending. © 2020 John Wiley & Sons, Ltd.

An Assessment of the Spatial and Temporal Distribution of Soil Salinity in Combination with Field and Satellite Data: A Case Study in Sujawal District

Soil salinization is a serious environmental issue that significantly influences crop yield and soil fertility, especially in coastal areas. Numerous studies have been conducted on the salinity status in Pakistan. Information about the geospatial and temporal distribution of salinity in the Sujawal district is still lacking. The present study examines the soil salinity status and the impact of seawater intrusion in the entire district from 1990 to 2017 using field and remote sensing (RS) data. In addition, 210 soil samples at different depths (0–20, 20–40, and 40–60 cm) were collected from randomly selected locations for lab measurements of physiochemical properties. The results showed that the soil texture classes were mainly fine to medium particles. The samples collected at the 0–20 cm depth were mostly dominated by three textural classes of soil: clay at 19.5%, clay loam at 25.6%, and loam at 32.9%. The electrical conductivity (EC) of 65.7% soil samples collected from the top layer exceeded the normal range. The quantitative results indicated that the exchangeable sodium percentage (ESP) ranged between 1.38 and 64.58, and 72.2% of the top layer soil samples had ESP >15, while 81.5% of soil samples were in the normal range of soil pH. Furthermore, the results indicated that the vegetation decreased by 8.6% from 1990 to 2017, while barren land and water bodies increased significantly, by approximately 4.4% and 4.2%, respectively. The extreme and high salinity classes were characterized by high contents of soluble salt on the surface in the Jati and Shah Bandar subdistricts. In addition, the soil EC values at the 0–20 cm depth were significantly correlated with the salinity index (S1). Therefore, it was concluded that more than 50% of the top layer of soil was affected by salinity due to seawater intrusion, low rainfall, climate change, and erratic river flow. It is suggested that remote sensing (RS) data are more suitable for the detection of the soil salinity status of a region and impose a lower cost compared to other conventional approaches. However, this study could provide significant knowledge to land managers, policymakers, and government officials to allow them to take action to implement salinity control measures in the study area.

Biyokömür ve Kükürt Uygulamasının Alkali Killi-Tınlı Topraklarda Fosfor Alınabilirliği ve Toprak Enzim Aktivitesi Üzerine Etkileri

Biochar (BC) has rich nutrient content and soil-improving properties. BC has recently been used as a fertilizer or soil amendment material. However, studies in which BC is applied with sulfur (S) are limited. In this study, effects of BC obtained from olive pulp and S separately and in combination with phosphorus (P) in soil with clay loam and high pH effects on enzyme activities -important for soil health- (acid phosphatase, alkaline phosphatase, β-Glucosidase and Dehydrogenase) have been examined. Different BC (0, 0.75%, 1.5%) and S (0, 800 mg kg-1) doses have been applied to the soil and incubated under controlled conditions for 45 days according to the factorial trial plan. According to the results of this study, BC and S interaction on electrical conductivity (EC), Total P and β-Glucosidase enzyme activity were found to be significant. BC and S application increased the total phosphorus amount, while both BC and S applications increased the available amount of P. However, BC and S resulted in an increase in soil EC value and S application decreased soil pH value. In addition, the amount of soil organic matter increased with the increase in the dose of BC. Strikingly while BC and S applications did not affect enzyme activity acid phosphatase, alkaline phosphatase and dehydrogenase, β-glucosidase enzyme activity was decreased in S application without BC application. This preliminary study shows that BC and S applications are required to be studied at appropriate field conditions and at appropriate doses.

Effects of Fusarium avenaceum and Rhizoctonia solani on the growth of soybean in saline soils

Soybean (Glycine max) acreage on the Canadian Prairies has increased rapidly in recent years. Production has expanded into semiarid regions where irrigation and drainage problems often result in the accumulation of salts in the soil. Fusarium avenaceum and Rhizoctonia solani are the two dominant pathogens in the disease complex that cause root rot and seedling blight of legume crops on the Canadian Prairies. The effects of F. avenaceum or R. solani in combination with soil salinity on soybean root rot were evaluated under greenhouse and mini-plot conditions. As expected, inoculation with F. avenaceum or R. solani consistently reduced seedling emergence and increased root rot severity in soybean. At high soil electrical conductivity values and inoculum densities, seedling emergence decreased and root rot severity increased in soybean in both trials with F. avenaceum and R. solani. Twenty short-season soybean cultivars that were well suited for production in Alberta were evaluated for their reactions to inoculation with F. avenaceum or R. solani in a saline soil (21.1 dS m−1). High seedling emergence was observed for cultivars 900Y61, P002T04R, 900Y01, TH27005RR, P001T34R, and 900Y81 in the non-inoculated control, for P002T04R and 900Y61 in the F. avenaceum treatment, and for 900Y61, 900Y81, and 900Y71 in the R. solani treatment. Root rot severity was low for cultivars NSC Portage and 900Y61 in the non-inoculated control and P002T004R in the F. avenaceum treatment. The cultivar 900Y61 also consistently had lower disease severity over the trials in the mini-plot test.

Mapping topsoil electrical conductivity by a mixed geographically weighted regression kriging: A case study in the Heihe River Basin, northwest China

Spatial prediction is an important approach to obtain location-specific values of soil electrical conductivity (EC), which is a proxy of soil salinity and important for agricultural management in arid and semi-arid areas. Linear regression models assume that the relation between soil EC and environmental covariates is constant over the area to be predicted. This is problematic at the regional scale, at which some of the regression parameters may indeed be globally constant, whereas others may vary locally. Moreover, model residuals often exhibit spatial dependence, which invalidates the ordinary least squares linear regression. This study examined the combination of a mixed geographically weighted regression model with simple kriging of the residuals (MGWGK) for mapping soil EC in the Heihe River Basin, an inland river basin in arid northwest China. We compared the performance of MGWRK with those of multiple linear regression (MLR), regression kriging (RK), geographically weighted regression (GWR), geographically weighted regression kriging (GWRK) and mixed geographically weighted regression (MGWR). Environmental covariates were developed from spatial information on topography, climate, vegetation, and geographic position. A ten-fold cross-validation was applied to evaluate predictive accuracy of the various methods. Soil EC ranged from 0.031 to 182.100 dS m−1, exhibiting a contrasting distribution of soil EC in the upper, middle, and lower river reaches. The MGWRK method outperformed other methods. The effects of different environmental covariates on soil EC were revealed by the fixed and geographically varying parameters of MGWRK. The nugget-to-sill ratios of fitted variogram models all fell between 25 and 32%, exhibiting moderate spatial autocorrelation of models residuals. Predictive accuracy was improved by MGWRK, as the spatial dependence of model residuals were included in the prediction. When selecting an optimal linear regression model, covariates should be tested to see if they are constant (as in MLR) or spatially varying (as in GWR) or semi-varying (as in MGWR), and model residuals should be tested for spatial dependence (as in MGWRK).

Changes in soil nutrients (ammonia, phosphate and nitrate) associated with rat carcass decomposition under tropical climatic conditions

Changes in soil nutrients have been applied in legal investigations of the time of death or to locate a clandestine grave. However, research on forensic soil chemistry under the tropical climate conditions in Malaysia is at its infancy, with few data available for forensic investigations. This study aims to study changes of soil nutrients (i.e. ammonia, phosphate and nitrate) as well as soil pH and electrical conductivity (EC), and the associated stages of decomposition of rat carcasses (n = 3) under controlled tropical climate conditions. The results showed differences in soil pH between control and carcass soils. Soil EC and concentrations of ammonia and phosphate increased during early decomposition stages, and declined thereafter. Nitrate concentration increased at the later stage of decomposition. We also found that the top layer of soil (i.e. 5 cm from surface) rendered a significant pattern of soil nutrient dynamics compared with soil at 10 cm from the surface, possibly due to a slower rate of vertical transfer and the washing-off effect. We suggest that the soil EC value and changes of soil nutrients in the top 5 cm of the soil layer have potential in forensic investigation to determine the minimum post-mortem interval and serve as an indicator for hidden graves and cadaver decomposition islands.

Effects of Anaerobic Digestate on Chinese Melon (Cucumis melo L.) Yield Components, Soil Properties, and Microbial Communities under Saline Irrigation Condition

ABSTRACTDigestate is increasingly utilized as a fertilizer, and earlier research was dedicated to plant growth and soil properties, with simple little information available regarding the effects of digestate on soil, plant, and microbial communities under saline irrigation. For this reason, a pot experiment with Chinese melon was conducted in a greenhouse, and digestate (1100 L ha−1) and a full recommended dose of NPK fertilizer were used. The melons were irrigated with normal water 0.25 (SL0) and 2 dS/m (SL1) using sodium chloride (NaCl). Application of digestate increased the melon plant height and leaves number significantly (p < 0.05) compared to control and treatments that received full NPK dose, under both water treatments (SL0 and SL1). The maximum plant height (SL0: 161 cm and SL1: 85.5 cm) and leaves number (SL0: 156.33 and SL1: 69.67) were observed when digestate used with NPK fertilizer. Plant fruit length, fruit diameter, sugar content, and yield increased significantly by digestate addition. The melon fruit sugar content values were 12% (SL0) and 9.83% (SL1). Soil electrical conductivity values increased when digestate combined with NPK fertilizer (1.4 dS m−1) particularly, under saline water, while the soil pH is not affected by digestate treatments. Digestate increased bacteria and decreased the number of fungi in the soil. Our results indicated that the usage of digestate could be more effective than NPK fertilizer on plant growth and soil properties. And there is a need to confirm these results in soils more realistic for agricultural field conditions and pay attention to use of digestate with saline irrigation water.

Remediation of heavily saline-sodic soil with flue gas desulfurization gypsum in Arid-Inland China

ABSTRACTSoil salinity is a major limiting factor for crop production in arid and semi-arid regions of northwest China. Flue gas desulfurization gypsum (FGDG) is valuable waste resource which can be used to improve saline soil. Monolith lysimeter leaching experiment was conducted with FGDG in heavily saline-sodic soil of northwest China. The four FGDG treatments with nine replicates for each treatment were applied when the FGDG rate was 0, 15, 30, and 60 t ha−1, respectively. Undisturbed sodic-saline soil was carefully collected in the 40-cm deep soil column. The results indicated that improvement effect on the depth of 0–10 cm soil layer was the best when the rate of FGDG was 60 t ha−1. It can reduce pH by 1.85, exchangeable sodium percentage (ESP) by 44%, and exchangeable Na+ by 7.37 cmol/kg in top soil layer. The values of the above soil parameters fell in the normal range due to FGDG treatment. At the same time, FGDG application reduced soil bulk density and increased saturated hydraulic conductivity. But from the maize growth, the emergence rate, plant height, shoot, and root weight were the best when the FGDG rate was 30 t ha−1. The results also showed that the FGDG application increased soil electrical conductivity value. Therefore, it is quite necessary to move saline ions into the deep soil layer through leaching process. Although effect of FGDG treatment of 60 t ha−1 on top soil was the best, considering the improvement effects of entire soil profile, we recommend that the optimum rate of FGDG was 30 t ha−1.

Effect of sewage sludge hydrochar on soil properties and Cd immobilization in a contaminated soil

To investigate hydrochar as a soil amendment for the immobilization of Cd, the characteristics of hydrochars (HCs) under three temperatures and residence times, were studied, with a particular interest in soil properties, as well as the speciation, availability and plant uptake of Cd. HCs were obtained by a hydrothermal carbonization (HTC) reaction of sewage sludge (SS). Based on the study of HC properties, we found that HCs present weak acidity with relatively high ash content and low electrical conductivity (EC) values. The addition of HCs to soil decreased soil pH and EC values but increased the abundance of soil microorganism. HCs also promoted the transformation of Cd from unstable to stable speciation and can decrease the content of phyto-available Cd (optimum condition and efficiency: A13,2 15.38%), which restrained cabbage from assimilating Cd from soil both the aboveground (optimum condition and efficiency: A35, 52.29%) and underground (optimum condition and efficiency: C15, 57.53%) parts of it.

Characterization of field‐scale dryland salinity with depth by quasi‐3d inversion of DUALEM‐1 data

AbstractTo understand the limitations of saline soil and determine best management practices, simple methods need to be developed to determine the salinity distribution in a soil profile and map this variation across the landscape. Using a field study in southwestern Australia, we describe a method to map this distribution in three dimensions using a DUALEM‐1 instrument and the EM4Soil inversion software. We identified suitable parameters to invert the apparent electrical conductivity (ECa – mS/m) data acquired with a DUALEM‐1, by comparing the estimates of true electrical conductivity (σ – mS/m) derived from electromagnetic conductivity images (EMCI) to values of soil electrical conductivity of a soil‐paste extract (ECe) which exhibited large ranges at 0–0.25 (32.4 dS/m), 0.25–0.50 (18.6 dS/m) and 0.50–0.75 m (17.6 dS/m). We developed EMCI using EM4Soil and the quasi‐3d (q‐3d), cumulative function (CF) forward modelling and S2 inversion algorithm with a damping factor (λ) of 0.07. Using a cross‐validation approach, where we removed one in 15 of the calibration locations and predicted ECe, the prediction was shown to have high accuracy (RMSE = 2.24 dS/m), small bias (ME = −0.03 dS/m) and large Lin's concordance (0.94). The results were similar to those from linear regression models between ECa and ECe for each depth of interest but were slightly less accurate (2.26 dS/m). We conclude that the q‐3d inversion was more efficient and allowed for estimates of ECe to be made at any depth. The method can be applied elsewhere to map soil salinity in three dimensions.

EFFECT OF USING IRRIGATION WATER IN DEFFIRENT QUALITIES AND BIO-FERTILIZER IN SOME CHEMICAL PROPERTIES OF CALCAREOUS SOIL

A pots experiment was conducted at the canopy wood of Agriculture - University of Baghdad (Abu-Ghraib) during summer season of 2014 to study the effect of irrigation water quality and biofertilizer and their interactions on some soil chemical properties and growth of corn. Treatments included three water qualities river water (1.5 ds.m-1 ''Q1''), well water (4.4 ds.m-1 ''Q3'') and mixed water (3.0 ds.m-1 ''Q2'') and two levels of biofertilizer (without inoculation ''B0'' and inoculation with Azotobacter chroococcum, Bacillus megaterium and Pseudomonas fluorescens ''B1'') applied to clay loam soil, using complete randomization design (CRD) in three replicates. The results of study Soil EC values increased with increasing water salinity giving 5.18, 6.03 and 6.70 ds.m-1 for Q1, Q2 and Q3, respectively. And significantly increased exchange capacity of the cation ions CEC reached 22.20, 23.01 and 24.31 c mole c kg-1 soil for Q1, Q2 and Q3, respectively. Irrigation water salinity also led to a significant increase in soil organic matter content reached 11.06, 12.55 and 13.90 gm.kg-1 soil for Q1, Q2 and Q3, respectively. Biofertilization led to decrease in rates a significant values electrical conductivity (EC) increase exchange capacity of the cation ions CEC and organic matter soil.

Combined effect of the fungicide based on copper sulfate and lead chloride

The present study aim to assess the effect of phosphate and urea fertilizers on the physicochemical properties, pH and electrical conductivity (EC) of the soil. The effect of these fertilizers on cation exchange capacity (CEC), organic matter (OM), and the possibility of contamination with heavy metals (HM) (Cr, Cu, Cd, Mn, Zn, Ni, Fe, and Pb) were studied on the soils of Alshati agricultural project at different seasons after forty years of fertilization. Uncultivated soil samples were also analyzed for comparison and considered as reference. Mean values of soil pH, EC, CEC, and OM ranged between 6.88-7.32, 0.14–0.26 μS/cm, 2.95–4.19 Cmol/kg and 0.49–0.53%, respectively, in all seasons. Concentrations of HMs were 9.50–38.38, 0.0–2.05, 0.0–0.47, 0.0–29.81, 0.0–13.85, 2.83–25.95 and 104–512.20 mg/kg respectively, for Cr, Cu, Cd, Mn, Zn, Ni and Fe. The concentrations of the HMs in the soil were found to be vary significantly with the seasons (winter, spring, summer, and autumn). However, no traces of Pb was found in the soil samples. The result showed a significant correlation between, pH, EC, CEC, OM and HM content of the soil. The geochemical index of contamination shows that there was no contamination with Cu, Cd, Zn, Pb, Cr, Mn, Ni, and Fe.