Properties Of Saline-sodic Soil Research Articles

Fusing Genotype and Soil Organic/Inorganic Amendment to Improve Saline-sodic Properties and Rice Productivity

Soil salinization and sodification have become a considerable threat to sustainable crop production for food security. The efficient biological practice in rice cropping systems, besides modulating saline-sodic soil properties using different amendments, is a necessary tactic to accelerate reclamation. This research aimed to evaluate the potential ameliorative effect of seven organic/inorganic amendments addition on soil properties and the differential responses of three rice genotypes under saline-sodic soil conditions at north of Egypt. A 2-year (2019 and 2020) field experiment was conducted with three rice genotypes, viz., Sakha 106, Giza 179, and Egyptian hybrid rice 1 (EHR1) cultivated in saline-sodic-affected soil amended with seven organic/inorganic amendments, i.e., gypsum, rice straw compost (RSC), farmyard manure (FYM), sulfur, sulfuric acid, calcium superphosphate, and rice husk beside control (unamended soil). This experimental design was a two-factor strip plot with randomized complete blocks with four replications. The morpho-physiological (SPADchlorophyll, water content, leaf area index, and shoot dry weight) and biochemical (catalase (CAT) activity, proline content, carbohydrates, leaf sodium (Na+) and potassium (K+), and Na+/K+ ratio) responses, the associated soil physico-chemical and microbial properties, yield, and its components were determined. RSC, gypsum, or sulfur were the most effective amendments in ameliorating saline-sodic soil properties by significantly reducing electrical conductivity, bulk density, and pH compared to the control and initial soil. Gypsum, RSC, FYM, or sulfur amendments significantly decreased the soil Na+ by 14.2, 11.7, 9.1, and 8.3%; sodium adsorption ratio by 14.9, 12.6, 10.4, and 8.7%; and exchangeable sodium percentage by 13.5, 11.5, 9.3, and 8.2%, respectively, over both seasons compared with control. The organic amendments surpassed inorganic regarding microbial biomass carbon, soil respiration rate, and dehydrogenase activity with the superiority of RSC, FYM, and rice husk over the control treatment. These soil restorations were favorably reflected in morpho-physio-biochemical parameters, yield, and its components for all the tested rice genotypes. The EHR1 is the superior genotype in terms of ion (Na+ and K+) selectivity, CAT activity, possessing lower proline and higher morpho-physiological responses, and productivity. The EHR1 had a considerable physiological effect on saline-sodic soil stress, producing higher yield (7.70 and 7.50 t ha−1) after treating with RSC or gypsum. This indicates that RSC outperforms other amendments in improving saline-sodic soils and enhancing rice productivity. Overall, a single application of rice straw compost (organic amendment) and gypsum or sulfur (inorganic amendment) is a viable sustainable approach for modulating saline-sodic soil’s physico-chemical and microbial properties and for boosting rice’s agronomic and physiological responses in an arid environment.

Compost mediates the recruitment of core bacterial communities in alfalfa roots to enhance their productivity potential in saline-sodic soils.

Composting is one of the effective environmental protection and sustainable measures for improving soil quality and increasing crop yield. However, due to the special physical and chemical properties of saline-sodic soil and the complex rhizosphere microecological environment, the potential mechanism of regulating plant growth after applying compost in saline-sodic soil remains elusive. Here, we investigated the effects of different compost addition rates (0, 5, 15, 25%) on plant growth traits, soil chemical properties, and rhizosphere bacterial community structure. The results showed that compost promoted the accumulation of plant biomass and root growth, increased soil nutrients, and enhanced the diversity and complexity of the rhizosphere bacterial communities. Moreover, the enriched core bacterial ASVs (Amplicon Sequence Variants) in compost treatment could be reshaped, mainly including dominant genera, such as Pseudomonas, Devosia, Novosphingobium, Flavobacterium, and Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium. The functions of these ASVs were energy resources and nitrogen cycle functions, suggesting the roles of these ASVs in improving plant root nutrient resource acquisition for alfalfa growth. The contents of available potassium, available phosphorus, total nitrogen, and organic carbon of the soil surrounding the roots, the root length, root surface area, root volume, and root tips affected the abundance of the core bacterial ASVs, and the soil chemical properties contributed more to the effect of plant biomass. Overall, our study strengthens the understanding of the potentially important taxa structure and function of plant rhizosphere bacteria communities, and provides an important reference for developing agricultural microbiome engineering techniques to improve root nutrient uptake and increase plant productivity in saline-sodic soils.

Desulfurization steel slag improves the saline-sodic soil quality by replacing sodium ions and affecting soil pore structure

Flue gas desulfurization steel slag (DS), a solid waste produced by coal power plants and steelworks, was proposed as an amendment for the remediation of saline-sodic soil. A pot experiment including three dosages of DS alone (1%, 5%, 10% w/w) and their combination with fulvic acid (FA, 1%, w/w) was conducted to evaluate the potentials of DS as an amendment and to explore remediation mechanism of DS combined with FA on saline-sodic soil. The soil salinity, nutrition, pore structure, water retention, consistency, and desiccation cracking of DS and FA-amended soils were determined. Application of DS resulted in a significant reduction of pH, sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) of saline-sodic soil. The DS amendment significantly increased the 6–15 μm pore volume of soil. The combination application of DS and FA showed better effect than the DS alone. The DS amendments at 5% and 10% significantly increased the field water capacity, permanent wilting point, and available water content of the soil, whereas significantly decreased the plastic limit, liquid limit, and plastic index. The DS alone and combined with FA could effectively control the development of desiccation cracking, reduced significantly the crack area density and average width of cracks of the soil. Consequently, the improvement of alkalinity and soil physical properties by DS amendment significantly increased the yield of alfalfa grown on saline-sodic soil. The remarkable improvement of physical properties of saline-sodic soil contributed to the decrease of SAR and ESP by the Ca2+ in DS replacing the Na + at soil colloid sites. Our results suggested that DS amendments alone or combined with fulvic acid have great potential as saline-alkali soil amendment.

Changes in soil characteristics and rice yield under straw returning in saline sodic soils

ABSTRACT Planting rice is one method to effectively utilize saline sodic land, but the rice yield is not high due to the saline sodic stress that affects rice growth. Straw return can improve soil fertility, but it is unknown whether the physicochemical properties of saline sodic soil can be improved by straw return and whether straw return can improve the productivity of saline sodic land. Therefore, we conducted a 4-year field trial to assess the effects of adding straw at 0, 2800, 4200, 5600, and 7000 kg ha−1 (CK, S1, S2, S3, and S4) on the soil physical properties, soil chemical properties, soil nutrients, and rice yield in saline sodic lands from 2017 to 2020. Our results show that a decrease in soil bulk density (BD) and a decrease in the percentage of < 0.053 mm particle size aggregates after straw incorporation depend on the straw incorporation rate. Soil exchangeable Na+ (ENa+) and exchangeable sodium percentage (ESP) were significantly lower in the straw treatments than in the CK treatment, and straw incorporation also had a positive effect on the reduction of soil pH and EC. Straw incorporation had a positive effect on the accumulation of soil organic matter (SOM) and total nitrogen (TN). SOM and TN gradually increased with the increase of straw incorporation rate. Rice yield showed a trend of increasing and then decreasing with the increasing straw incorporation rate, with the highest yield under the S3 treatment at a four-year average yield of 8.57 t ha−1. There was no significant difference between the S3 and S4 treatments in soil physical structure, chemical properties, or nutrients during the experiment. Therefore, we conclude that a reasonable amount of straw incorporation for improving saline sodic soil properties as well as for increasing rice yield in the first four years is 5600 kg ha−1 (S3 treatment).

Efficiency of Different Conditioner Compositions Formulated for Improving Physicochemical Characteristics of Calcareous Saline-Sodic Soils

ABSTRACT The saline and sodic nature of the soil is considered a major plant growth-limiting factor in many agricultural regions. In this experiment, three soil amendments containing sodium polyphosphate, lignosulfonate, amino acid, polyethylene glycol and different ratios (w:w) of H2SO4 to citric acid, i.e.,, 0:9 (CF1), 3:6 (CF2), and 3:3 (CF3) were provided and their efficiency in improvement of soil characteristics was evaluated. The amendments were added into the leaching water at application rates of 0, 1000, 2000, and 3000 L ha−1 at four stages. The final soil ECe values indicated the effective leaching of the salts from the soil columns for both amendments and the control. All the amendments decreased soil ESP with less effectiveness at the higher application rates. The CF1 and CF2 at the low to medium application rates (1000 and 2000 L ha−1) effectively increased soil hydraulic conductivity (HA) over the control while they were ineffective at the highest application level (3000 L ha−1). The increase of the HA was accompanied with a significant decrease in the dispersible clay and an increase in the available water content. Soil penetration resistance was also lower in the soils treated with the CF1 and CF2 at the application rates of 1000 and 2000 L ha−1. According to the results, CF1 and particularly CF2 at the application rate of 1000 L ha−1 might be recommended for improving physical properties of saline-sodic soils, although further studies particularly under field conditions are needed.

Organic Substitution Increases Sunflower (Helianthus Annuus L.) Yield and Water-Fertilizer Productivity by Improving Saline-Sodic Soil Properties in an Arid Area

Organic Substitution Increases Sunflower (Helianthus Annuus L.) Yield and Water-Fertilizer Productivity by Improving Saline-Sodic Soil Properties in an Arid Area

Flue gas desulfurization (FGD) steel slag ameliorates salinity, sodicity, and adverse physical properties of saline-sodic soil of middle Yellow River, China.

Saline-sodic soil is considered the most important low-yield soil in arid and semi-arid regions. Flue gas desulfurization (FGD) steel slag is a kind of by-product from wet FGD process, in which steel slag powder replaces lime as sorbent of SO2 emitted from coal-fired power plants. It could potentially be used to ameliorate saline-sodic soil. In this study, a large-scale field experiment of applying FGD steel slag as a new amendment of saline-sodic soils was conducted in the middle YellowRiver, Inner Mongolia, China. The FGD steel slag was applied at a rate of 180 t/ha in 2015, 2016, and 2018, respectively. After FGD steel slag application for 1, 3, and 4 years, the soil samples were collected. The saline-sodic field without FGD steel slag amendment was used as the control treatment (CK). Compared with control, the application of FGD steel slag significantly (p < 0.05) decreased soil pH, electric conductivity (EC), salt content, sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) of surface soil in saline-sodic soil. However, FGD steel slag increased the EC and salt content at the lower depth of soil profile because of the salt accumulation leached from surface soil. The FGD steel slag significantly increased the concentration of Ca2+ and reduced the concentrations of Na+, Cl-, CO32-, and HCO3- ions. FGD steel slag was beneficial for improving adverse physical properties of saline-sodic soil. The application of FGD steel slag significantly reduced the plastic index, tensile strength, and the formation of cracking in saline-sodic soil. The FGD steel slag reduced surface area density of crack (Dc) and average crack width (AW) by 49.1% and 58.7%, compared with the control. The reduction of soil cracking was contributed to the release of Ca2+ from FGD steel slag to exchange the Na+ on the soil cation exchange sites, which decrease the clay dispersion in soil. The findings of this study confirmed that FGD steel slag could effectively and rapidly remediate saline-sodic soils through decreasing soil sodicity and improving poor physical properties.

Investigating the effects of cow manure, vermicompost and Azolla fertilizers on hydraulic properties of saline-sodic soils

Purpose Soil salinity and sodicity are among the factors involved in soil degradation, especially in arid and semi-arid areas of the world. The use of modifiers, including organic matters, can be considered as an appropriate strategy to improve the fertility of saline-sodic soils. Method In this study, saline-sodic control soil was collected from Karaj and mixed with three levels of 1%, 3% and 5% of cow manure, vermicompost and Azolla. The soil columns were then incubated at 20 °C and field capacity moisture for 5 months. The physical and chemical properties of the treatments were evaluated before and after incubation. Results After the incubation period, the lowest salinity level was observed in 5% Azolla and vermicompost treatments. The highest amount of change in sodium absorption ratio was related to 5% cow manure treatment. There was an insignificant difference in moisture levels in a given suction among the different treatments. After the incubation period, salinity and sodium absorption decreased and increased in most of the treatments, respectively. Moreover, the decrease of saturation dehydration coefficient in the treatments revealed the disruption of soil structure and conversion of large pores to fine grains as a result of adding the mentioned organic matters. Conclusion According to the results, cow manure at 1% level had no significant effect on soil properties. However, at higher levels, it had a negative effect on quality and conditions of the saline-sodic soil in terms of physical and chemical properties. In contrast, Azolla and vermicompost fertilizers at 5% proved to be suitable for correcting the saline-sodic soil.

Assessing the impact of water treatment residuals and rice straw compost on soil physical properties and wheat yield in saline sodic Soil

ABSTRACT Rice straw compost (RC) and water treatment residuals (WTR) can improve both organic wastes recycling and soil physical properties of salt-affected soils. Therefore, the aim of this study was to test the effect of RC and its mixture with WTR on some physical properties of the saline-sodic soil, and wheat yield. The treatments were RC, WTR, and RC + WTR mixture at rates of 12 and 24 t ha−1. The results indicated that the application of RC alone or combined with WTR significantly increased drainable porosity (DP), total porosity (TP), mean weight diameter (MWD) and total water-stable aggregates (WSA) as compared to control. The increase in soil DP under the 24 t of WTR ha−1 was 64.7% greater than the control treatment. The mixtures of RC +WTR gave better results in increasing the dry weight and grain yield, especially the rate of 24 t of RC +WTR (1:2) ha−1 soil as compared to adding them individually. The experimental results concluded that the WTR + RC mixture can be used as a promising strategy to increase wheat yield and improve the efficiency of recycled rice straw and WTR on the physical properties of saline-sodic soils.

A vermicompost and deep tillage system to improve saline-sodic soil quality and wheat productivity

Land degradation due to soil salinity and sodicity is a serious concern in arid ecosystems. Despite the importance of conservation tillage in carbon sequestration and improving soil properties, its effect on saline-sodic soils under amendment application remains unknown. Therefore, the present study aimed to explore the combined effects of inorganic (sulfuric acid and gypsum) and organic (vermicompost) soil amendments and tillage systems (zero, reduced and deep tillage) on saline-sodic soil properties and wheat productivity. Deep tillage with vermicompost application significantly improved soil physical and chemical properties compared with control. Interestingly, integration between deep tillage and vermicompost decreased soil salinity and sodicity by 37% and 34%, respectively, compared with zero tillage and unamended soils. The application of vermicompost surpassed chemical amendments in the improvement of saline-sodic soils and consequently increased the growth and yield of wheat, provided that deep tillage was used as a suitable tillage system. Although deep tillage reduced soil organic carbon, application of vermicompost not only compensated this reduction, but also significantly increased soil organic carbon. This confirms the potential of combined deep tillage and vermicompost as a method for environmentally reclaiming saline-sodic soils.

Use of a stabilized sewage sludge in combination with gypsum to improve saline-sodic soil properties leached by recycled wastewater under freeze-thaw conditions

Soil salinization is a major environmental hazard that limits agricultural production. Using sewage sludge and recycled wastewaters in amelioration of saline-sodic soils is one of the most effective ways to dispose waste. However, a very low initial permeability of soil in the freeze-thaw conditions can make improvement difficult. Therefore, column experiments at a soil depth of 15 cm have been conducted to determine the effects of the combination of four stabilized sewage sludge doses (0, 50, 100, 150 t ha−1), three freeze-thaw cycles (0, 5, 10 times) and two water types (FW: freshwater, RWW: recycled wastewater) on gypsum-treated saline-sodic soil properties. The effects of non-saline-sodic RWW on the soil properties were similar to the FW in total 22.5 cm leaching amount. Compared to gypsum alone and initial values, sewage sludge increased wet aggregate stability, organic matter, total N and exchangeable Ca + Mg while it decreased pH, exchangeable Na and CaCO3. Saturated hydraulic conductivity was not induced by sewage sludge although exchangeable sodium percentage and electrical conductivity were reduced by 44% and 63.6%, respectively. Negative effects of freeze-thaws on hydraulic conductivity and salinity and sodicity elimination were not observed, while pH and aggregate stability were negatively affected from ten freeze-thaws. Overall, it can be concluded that the improvement of hydraulic conductivity is attributed to the further improvement of soil structure from more strong wet aggregate stability via additional sewage sludge and leaching amounts.

Changes in some chemical properties of saline-sodic soils over time as affected by organic residues: An incubation study

&lt;p&gt;Salinization and sodification of agricultural lands in arid and semi-arid regions of the world are two limiting factors in the crop production. This study was conducted to evaluate the effect of readily available agricultural residues on changing some chemical properties of saline-sodic soils. Wheat, potato, sunflower, and canola residues were separately added into three saline-sodic soils at a rate of 2% by weight and thoroughly mixed with soils. Control and treated soils were incubated for 168 days at a constant moisture and temperature. The pH, electrical conductivity (EC), soluble cations, available nitrate (NO3-) and phosphorous (P), cation exchange capacity (CEC), and exchangeable sodium percentage (ESP) were measured during the incubation. The EC increased in the response to the incorporation of plant residues, whereas the pH was reduced. The application of organic components in soils increased CEC and decreased ESP. The results showed that the maximum reduction in ESP was observed in the potato treatment because of the highest Ca2+ concentration. The average reduction in ESP of treated soil samples at the end of incubation followed this order: 16.1% (potato residue-treated soil) &amp;gt;12.7% (canola residue-treated soil) &amp;gt;11.1% (wheat residue-treated soil) &amp;gt;9.6% (sunflwer residue-treated soil). The potato residue was the most effective amendment in changing the chemical properties of saline-sodic soils in comparison with other organic residues. The results indicated that the application of organic residues had a positive impact on reducing the soil sodicity and improving the soil fertility depending on their chemical composition.&lt;/p&gt;

Effects of treatment application rates (fym and gypsum) on selected chemical properties of saline sodic soils under water limited condition in eastern lowlands Ethiopia

A laboratory incubation experiment was carried out on saline sodic soils collected from Babile, Eastern Ethiopia to evaluate and compare the potentials of gypsum and farm yard manure (FYM) treatments for the reclamation of saline sodic soils. The treatment tested consisted of combination of six rates of gypsum (0, 25, 50, 75, 100 and 125% gypsum requirement) and four rates of farmyard manure (0, 10, 20 and 30 tons FYM ha-1) in a completely randomized design (CRD) replicated three times. Results revealed that sole and combined application of treatments significantly (P&lt;0.001) improved soil pH, electrical conductivity saturated paste (ECe) and ESP over the control. Maximum reduction in soil pH (14.14%), ECe (48.99%) and ESP (16.20) recorded in soils treated with combined 30 tons FYM ha-1 and gypsum (125% GR) treatments. Furthermore, soils treated with sole application of gypsum at higher rates (50, 75,100 and 125% GR) achieved significantly higher reduction in soil pH, ECe and ESP than sole application of FYM. However, combined applications of FYM and gypsum were relatively more efficient than either one alone in removing exchangeable Na under condition of water limitation for dissolution. Hence, it may be concluded that all combinations of 20 and 30 tons FYM ha-1 with gypsum (50, 75,100 and 125% GR) rates reduced the soil pH, EC and ESP to agricultural permissible level.

Amelioration of Some Physical Properties of Saline Sodic Soil in El-Tina Plain- North Sinai Area

Amelioration of Some Physical Properties of Saline Sodic Soil in El-Tina Plain- North Sinai Area

Integrated effect of nano-Zn, nano-Si, and drainage using crop straw–filled ditches on saline sodic soil properties and rice productivity

Soil salinity and sodicity issues due to limited water resources and arid climate are the main sources of land degradation in the North Nile delta. Moreover, burning rice and cotton straw is a very common practice in this region contributing to global warming and further polluting the environment. Improving saline sodic properties by biological drainage has received less attention so far. The study aimed to evaluate the effect of burying some crop residuals in field ditches and foliar application of nanoparticles on salt affected soil properties and rice productivity. The obtained results revealed that burying rice or cotton straw in field ditches prior to rice planting resulted in significant increase in rice yield and its components with superiority of cotton stalk–filled ditches to that filled by rice straw especially in the second season. Likewise, the incorporation of crop residual improved soil properties including soil fertility. The decomposition of rice straw or cotton stalk obviously decreased soil electric conductivity and soil compaction and slightly decreased bulk density. Also, soil hydraulic conductivity and organic matter content were positively responded to incorporation of crop residues. In addition, the availability of N and Zn in soil was increased due to the application of crop residues. The yield and yield components of rice were significantly affected by the foliar application of nano-Si and Zn with superiority of nano-Zn. Also, soil properties such as soil salinity, bulk density, soil compaction, hydraulic conductivity, organic matter, and available nitrogen were slightly affected by these nanoparticles while the available Zn was clearly increased.

The impact of irrigation on yield of alfalfa and soil chemical properties of saline-sodic soils.

BackgroundForage production in the saline-sodic soil of the western Songnen Plain Northeast China depends on irrigation. Therefore, the water use efficiency (WUE) and soil chemical properties are key factors in the overall forage productivity in this water scarce region. Improving forage yield, WUE, and soil properties under irrigation are very important for food and ecological security in this water-deficient region. Additionally, a suitable irrigation schedule for this region is necessary.MethodsA field experiment was conducted between 2015 and 2018 to evaluate the effects of irrigation on artificial grassland productivity and the changes in soil chemical properties as well as to plan a reliable irrigation schedule for the western Songnen Plain. Eight irrigation treatments were designed, which depended on the three growth stages of alfalfa. The shoot height (SH), the chlorophyll content (SPAD), the dry yield (DM), the ratio of stem to leaves (SLR), the WUE, the changes in the chemical properties of the soil, and precipitation and evaporation were investigated.ResultsThe SH, DM, WUE, and SLR were significantly increased by irrigation (P < 0.01). However, the SPAD resulting from irrigation was not significantly higher than the SPAD of CK (no irrigation) (P < 0.05). In addition, the soil chemical properties at the depth of 0–100 cm were significantly decreased by irrigation P (0.05). For example, the soil electrical conductivity, sodium absorption ratio, and total alkalization were reduced 182–345 μS cm−1, 8.95–9.00 (mmolc/L)1/2, and 3.29–4.65 mmolc L−1 by different irrigation treatments, respectively. Finally, considering the highest WUE of I5 (irrigation at branch stage) (2.50 kg m−3), relative high DM of I5 (787.00 g m−2), the precipitation, the evaporation, the water resources, and the changes of the soil’s chemical properties, 236.50 mm of irrigation water was recommended at the branching stage of alfalfa for the western Songnen Plain, Northeast China.

Effect of Gypsum, Sulfuric Acid, Nano-Zeolite Application on Saline-Sodic Soil Properties and Wheat Productivity under Different Tillage Types

Effect of Gypsum, Sulfuric Acid, Nano-Zeolite Application on Saline-Sodic Soil Properties and Wheat Productivity under Different Tillage Types

Aggregate-related changes in soil microbial communities under different ameliorant applications in saline-sodic soils

Soil ameliorants can improve soil physico-chemical properties and activate microbial communities in saline-sodic soils. However, there has been less focus on how aggregate fractions affect soil microbial communities under different ameliorant applications. Here, we used the phospholipid fatty acid (PLFA) analysis to explore the effects of soil ameliorants on microbial communities within mega-aggregates (diameter of >2 mm, ME), macro-aggregates (diameter of 0.25–2 mm, MA), and micro-aggregates (diameter of <0.25 mm, MI), based on an 8-year rice (Oryza sativa L.) field experiment. The five treatments included CK, non-amended control; SS, amended with sandy soil; DG, amended with desulfurization gypsum; FM, amended with farm manure; and M, amended with a mixture of sandy soil, desulfurization gypsum, and farm manure. Relative to the CK treatment, the SS, DG, FM, and M treatments significantly decreased the soil pH and electrical conductivity and significantly increased the soil organic carbon (SOC) content of the MI, while the FM and M treatments also significantly improved the SOC content of the MA and ME. Irrespective of the ameliorant used, the absolute abundance of total PLFAs and most microbial groups generally varied with the SOC content as follows: MA > ME > MI. Meanwhile, the proportional abundance of arbuscular mycorrhizal fungi (AMF) varied between different aggregate fractions as follows: ME > MA > MI. Additionally, the DG treatment significantly enhanced the soil aggregate stability by increasing the AMF abundance, AMF/saprotrophic fungi ratio, and SOC content of the MI. Furthermore, soil microbial groups were highly correlated with soil SOC (P < 0.001), C/N ratio (P < 0.001), pH (P < 0.01), total nitrogen (P < 0.01), and the proportion of aggregates with a >0.25 mm diameter (P < 0.05). In conclusion, desulfurization gypsum is more effective for improving the properties of saline-sodic soils in the western Songnen Plain.

Spatial scaling of soil salinity indices along a temporal coastal reclamation area transect in China using wavelet analysis

ABSTRACTHigh spatial variability of soil salinity in coastal reclamation regions makes it difficult to obtain accurate scale-dependent information. The objectives of this study were to describe the spatial patterns of saline-sodic soil properties (using soil pH, electrical conductivity (EC1:5) and sodium ion content (SIC) as indicators) and to gain knowledge of the scaling relationships between those variables. The soil pH, EC1:5 and SIC data were measured at intervals of 285 m along a 13,965-m temporal transect in a coastal region of China. The spatial variability of soil pH was weak but it was strong for soil EC1:5 and SIC at the measurement scale. There was a significant positive correlation between soil EC1:5 and SIC, while correlations between soil pH and either EC1:5 or SIC were weak and negative. For each saline-sodic soil parameter, the variability changed with the decomposition scales. The high-variance area at the larger scales (≥570 m) occupied less than 10% of the total area in the local wavelet spectrum, which meant that the spatial variations of the salinity indicators were insignificant at these scales. For local wavelet coherency, at a scale of 1500–2800 m and a sampling distance of 0–4500 m, the covariance was statistically significant between any two of the saline-sodic soil parameters.

Effects of Vermicompost and Water Treatment Residuals on Soil Physical Properties and Wheat Yield

Abstract The application of vermicompost and water treatment residuals to improve the physical properties in the salt affected soils is a promising technology to meet the requirements of high plant growth and cost-effective reclamation. Therefore, the aim of this study was to investigate the effect of vermicompost and its mixtures with water treatment residuals on selected physical properties of saline sodic soil and on wheat yield. The treatments were vermicompost, water treatment residuals, vermicompost + water treatment residuals (1:1 and 2:1 wet weight ratio) at levels of 5 and 10 g dry weight kg-1 dry soil. The considered physical properties included aggregate stability, mean weight diameter, pore size distribution and dry bulk density. The addition of vermicompost and water treatment residuals had significant positive effects on the studied soil physical properties, and improved the grain yield of wheat. The treatment of (2 vermicompost + 1 water treatment residuals) at level of 5 g kg-1 soil gave the best grain yield. Combination of vermicompost and water treatment residuals improved the water treatment residuals efficiency in ameliorating the soil physical properties, and could be considered as an ameliorating material for the reclamation of salt affected soils.