Exchangeable Sodium Percentage Research Articles

Ameliorating saline‐sodic soils: A global meta‐analysis of field studies on the influence of exogenous amendments on crop yield

AbstractAs the demand for food continues to rise, soil salinization and sodification pose an increasingly pressing challenge. Currently, there is a knowledge gap regarding how to effectively improve saline‐sodic soils to support sustainable agricultural production, especially the lack of systematic analysis on the effects of different amendments at a global scale. To address this gap, this study aims to explore the feasibility of using exogenous amendments to ameliorate saline‐sodic soils, conducting a global‐scale meta‐analysis based on 685 data pairs from 70 published studies. Our results showed that applying amendments to saline‐sodic soils significantly reduced electrical conductivity of saturated paste extract (ECe) by 33.0% and exchangeable sodium percentage (ESP) by 44.6%, while simultaneously increasing crop yield by 50.7%. Heterogeneity analysis further unveiled significant variations (p < 0.05) in the overall effect size, driven by factors such as initial soil properties (salinity and ESP levels), amendment type, climate and practical management conditions (application dose and experimental duration). The categorical variable analysis showed that, compared to soils with other salinization levels, the application of amendments in severe salinization soils was most effective in reducing soil ECe and enhancing crop yield. Considering the goals of mitigating soil salinity, sodicity, and increasing crop yield, the study suggests the application of mixed‐type amendments in practical settings. It is noteworthy that while extremely high doses (greater than 40 t ha−1) effectively increased crop yield, they also posed a risk of salt accumulation. In conclusion, this research offers critical insights for sustainable agriculture, guiding future work on soil health and food security in the context of global environmental challenges.

The potential of NAA and ICP-MS for determining soil dispersibility in relation to landslide incidents

Dispersive soils pose significant challenges due to their inherent tendency to rapidly respond to the presence of water, resulting in erosion and heightened susceptibility to landslides. The inclusion of sodium (Na) onto the surface of soil clay particles results in the attenuation of the electrochemical interactions between the dispersed soil, leading to the repulsion and subsequent migration of the clay particles away from one another. This study employed Neutron Activation Analysis (NAA) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to assess the Sodium Adsorption Ratio (SAR) and Exchangeable Sodium Percentage (ESP) as indicators of soil dispersibility. The results indicate that soils containing montmorillonite clay mineral exhibit greater values of SAR > 11 and ESP > 20 in comparison to soils containing other clay minerals i.e. kaolinite, illite, and vermiculite. The calculated SAR and ESP values obtained from both analyses demonstrate a notable agreement, indicating a positive correlation. In conclusion, it is apparent that both NAA and ICP-MS method has the capability to be applied for the purpose of predicting soil dispersibility in landslide-prone regions of Malaysia.

Long-term effects of biochar one-off application on soil physicochemical properties, salt concentration, nutrient availability, enzyme activity, and rice yield of highly saline-alkali paddy soils: based on a 6-year field experiment

Biochar application can alleviate the adverse effects of saline-alkali stress on crops. However, the long-term effects of one-off biochar application on soil physicochemical properties, salt concentration, nutrient availability, soil enzyme activities, and rice yield under highly saline-alkali paddy soils remain unclear. Here, a 6-year paddy field study was conducted in a saline-alkali paddy field using two nitrogen application levels (0 and 225 kg ha−1) and four biochar application rates [0 (T0), 1.5% (T1.5), 3.0% (T3.0), and 4.5% (T4.5) biochar, w/w]. The results showed that compared with T0, the bulk density (BD) under T1.5, T3.0, and T4.5 treatments significantly decreased by 11.21%, 16.33%, and 25.57%, while total porosity (Tp) and saturated hydraulic conductivity (Ks) increased by 19.15–27.34% and 3217.78–5539.83%, respectively. Biochar consistently improved soil macro-aggregates, mean weight diameter (MWD), and the percentage of water-stable aggregates (PWSA) over the years. Additionally, one-off application of biochar continuously reduced the soil Na+ concentration, Na+/K+ ratio, Na+/Ca2+ ratio, saturated paste extract (ECe), exchangeable sodium percentage (ESP), and sodium adsorption ratio (SARe). However, it reduced the pH in 2021 and 2022 only. It enhanced the concentration of K+, Ca2+, Mg2+, and cation exchange capacity (CEC) over the 6-year study, indicating its longer-term positive impact. Furthermore, the one-off biochar application, especially under high application rate treatments (T3.0 and T4.5), significantly and continuously improved nutrient availability and soil enzyme activities. However, alkali-hydrolysable nitrogen (AN) decreased in the initial year of biochar application. The grain yield of T1.5, T3.0, and T4.5 surpassed that of T0 by 116.38%, 141.24%, and 145.20%, respectively. Notably, the rice yield reached its peak with the treatment of 3.0% (w/w) in all 6 years of study period. These findings offered new perspectives on repairing and improving soil quality and production ability of highly saline-alkali paddy soils.Graphical

Conservation agriculture works as a catalyst for sustainable sodic soil reclamation and enhances crop productivity and input use efficiency: A scientific inquiry

Soil sodicity is a growing concern for crop growth and development in arid and semi-arid regions of the world. Conservation agriculture (CA) provides an effective solution towards reclamation of degraded sodic lands and enhance the crop productivity. A field experiment was carried out to assess the sodic soil reclamation potential of CA based management practices including zero tillage, legume (mungbean; Mb) rotation, residue (+R) mulch, and subsurface drip irrigation (SDI) for three years under rice-wheat (RW) system. The system scenarios (Sc) comprised of multiple indicators to measure their impact on soil properties as well as system productivity, profitability, water and nitrogen use efficiency. The results indicated that soil pHs under Sc5-Sc8 (CA-based SDI scenarios) was significantly (p < 0.05) lowered by 2.16, 2.16 and 1.33% compare with mean of Sc1 and Sc2 (CT-based system; 9.10, 8.29 and 8.14) at all three soil layers (0-5, 5-15 and 15-30 cm), respectively. Similarly, the exchangeable sodium percentage (ESP) was lowered by 2.9, 11.2 and 14.9% under CA-based scenarios with residue management compared with CT-based system (mean of Sc1 and Sc2; 15.2, 17.2 and 28.6%) during the study. The concentration of extractable anions (COЗ2‾, HCOЗ‾, Cl‾) decreased notably whereas, soil organic carbon and soil solution cations (Na+, Ca2+, Mg2+) concentration were increased under CA based management SDI plots. In addition, CA with SDI scenarios (mean of Sc5-Sc8) proved to be more productive and water-efficient than CA-based flood irrigation (FI; mean of Sc3 and Sc4). Moreover, CA-based FI and SDI scenarios saved 29.5 and 60.7% irrigation water, and improved the partial factor productivity of nitrogen (PFPN) by 6.8 and 24.4%, respectively compared to CT-R (conventional tillage without residue) based Sc1. Therefore, CA practices can potentially reduce sodicity and improve soil chemical properties for profitable crop cultivation.

Nutrient status and production of fodder beet irrigated with saline-sodic water in Mediterranean calcareous soils

ABSTRACT The impact of drip irrigation with saline-sodic water on the nutrient status and productivity of fodder beet (Beta vulgaris) was evaluated in rainy and dry Mediterranean cropping seasons. Two field experiments were conducted during two growing seasons (winter and summer) in calcareous soil (31% CaCO3) of Sais area, Northwestern Morocco. The rainfall was 337 mm for winter and 53 mm for summer. Four salinity levels of irrigation water (ECi) were investigated: control (1ds m−1), 4, 6, and 10 ds m−1. The ECi levels were prepared by adding sodium chloride (NaCl, laboratory grade, 99.5%) to water. The results showed that the soil salinity (ECs) was related to the growing season and the irrigation water salinity (ECi). The depressive effect of salinity on the whole plant dry biomass (−25% as average) was observed only in the summer crop cycle at different ECi ≥ 4 ds m−1 compared to control. The plant NaCl uptake for both seasons could be predicted by a linear model: Y (kg ha−1 of NaCl) = 36.3 ECi + 23.6 Q − 101.3 (adjusted R2 = 0.88) where Q = total dry biomass (t ha−1). Saline-sodic irrigation water reduced the contents of boron, calcium, and magnesium in the plants. The exchangeable sodium percentage (ESP) in the soil exceeded 41% at ECi ≥ 4 ds m−1 for both seasons. The study demonstrated that fodder beet escapes the negative impact of salt stress in the rainy season. However, the high ESP recorded at harvest did not reveal the efficacy of fodder beet in NaCl removal from the soil.

Interactive influences of salinity and sodicity levels on depth-wise soil organic matter and micronutrient elements in Thailand

Soil salinity and sodicity are the major environmental issues that lead to the deterioration of soil properties, nutrient cycling, and soil ecosystems around the globe. Nevertheless, the reciprocal effects of salinity and sodicity levels on depth-wise soil organic matter (SOM) and micronutrients remain elusive, particularly in Thailand. For a better understanding of such an issue, soil samples were collected from 38 sites at depths of 0–20, 30–50, 60–80, and 80–120 cm where they were affected by salts with variable levels of salinity and sodicity, having electrical conductivity (ECe), and exchangeable sodium percentage (ESP) from 0.20–74.70 dS m–1, and 2.74%–113.23%, respectively. Soil physicochemical properties, including distribution of sand, silt, and clay, pH, soil organic carbon (SOC), and micronutrients (Fe, Zn, Mn, Cu, and B) were determined. The results exhibited that SOC content, ranging from 3.36–14.74 g kg–1, was higher in topsoil (0–20 cm) compared to the other three soil depths and it correlated negatively with ECe (0–20 and 80–120 cm) and ESP (80–120 cm), suggesting the declines in SOC amount due to high salinity and sodicity levels. Topsoil Mn concentration (0.06–182.06 mg kg–1) also tended to be greater than the other soil depths while Fe concentration in that soil depth (0.02–33.99 mg kg–1) tended to be smaller. The ECe correlated negatively with the concentrations of Fe, Cu (all soil depths), and Zn (30–50 and 60–80 cm), and positively with Mn concentration (60–80 and 80–120 cm), suggesting that the availability of Fe Cu and Zn is vulnerable to high salinity and sodicity levels. Overall, our findings highlight that high salinity and sodicity levels brought about a reduction in SOC content and low concentrations of micronutrients in soils, irrespective of Mn concentration.

Elucidating Amendment Resources for Reclaiming Efficacy of Sodic Soils around Abaya and Chamo Lakes, South Ethiopia Rift Valley.

Sodic soils are harmful to agricultural and natural environments in Ethiopia's semi-arid and arid regions, leading to soil degradation and reduced productivity. This study investigated how amendment resources could help improve the chemical properties of sodic soils around the Abaya and Chamo Lakes in the South Ethiopia Rift Valley. A factorial experiment was conducted to study the effects of gypsum (GYP) and farmyard manure (FYM) on sodic soil reclamation. The experiment had four levels of GYP (0, 50, 100, and 150%) and four levels of FYM (0, 10, 20, and 30 tons ha-1), with three replications. The pots were incubated for three months and leached for one month, after which soil samples were collected and analyzed for chemical properties. ANOVA was performed to determine the optimal amendment level for sodic soil reclamation. The study found that applying 10 ton FYM ha-1 and gypsum at 100% gypsum required (GR) rate resulted in a 99.8% decrease in exchangeable sodium percentages (ESP) compared to untreated composite sodic soil and a 1.31% reduction over the control (GYP 0% + FYM 0 ton ha-1). As a result, this leads to a decrease in soil electrical conductivity, exchangeable sodium (Ex. Na), and ESP values. The results were confirmed by the LSD test at 0.05. It is fascinating to see how different treatments can have such a significant impact on soil properties. The prediction models indicate that ESP's sodic soil treatment effect (R2 = 0.95) determines the optimal amendment level for displacing Ex. Na from the exchange site. The best estimator models for ESP using sodic soil treatment levels were ESP = 1.65-0.33 GYP for sole gypsum application and ESP = 1.65-0.33 GYP + 0.28 FYM for combined GYP and FYM application, respectively. The study found that combined GYP and FYM applications reduced ESP to less than 10% in agriculture, but further research is needed to determine their effectiveness at the field level.

Silicon Improves Soil Environment and Promotes Crop Growth under Compound Irrigation via Brackish Water and Reclaimed Water

Not only is solving freshwater resource shortages effective but also an important measure for realizing the sustainable development of agriculture through the development and use of unconventional water resources. This pot experiment investigated the role of exogenous silicon in the risk of secondary soil salinization and the growth physiology of Lvxiu pakchoi cabbage under irrigation by using brackish water alone (BW), reclaimed water alone (RW), and compound irrigation with brackish water and reclaimed water at a ratio of 1:1, as well as the distribution of silicon in a soil–crop system. The results showed that with the extension of the spraying period of silicon fertilizer, the electrical conductivity (EC) decreased under 1:1 compound irrigation. The pH values in all treatments ranged from 7.95 to 8.10 without a potential risk of alkalization. Spraying silicon fertilizer had a positive effect on increasing the ratio of exchangeable potassium to sodium in soil. Spraying silicon fertilizer significantly reduced the percentage of exchangeable sodium (ESP) and the sodium adsorption ratio (SAR) in soils irrigated using BW, and increased the soil ESP and SAR under compound irrigation and RW irrigation, but these factors did not exceed the threshold of soil salinization. The proper application of silicon fertilizer had no significant effect on the total silicon content in the soil but increased the total silicon content in the plants to some extent. In addition, the yield was improved through proper silicon fertilizer application. In summary, exogenous silicon has positive effects on soil physical and chemical properties and crop growth, and relieves secondary salinization risk under compound irrigation via brackish water and reclaimed water.

Can gypsum and organic amendments achieve sustainability, productivity and maintain soil health under soybean-mustard cropping in sodic soils of western India

Soil salinity is a major environment stress impairing crop production and accelerating soil degradation. Use of soil amendments are practical solutions for altering soil quality to enhance crop productivity in these soils. Hence, we systematically evaluated the impact of soil amendments practices on crop productivity, nutrient use efficiency, soil properties, soil quality index, economics and energetics on soybean-mustard cropping system in sodic Vertisol. In this study, eight treatments comprising of various combinations of soil amendments such as gypsum (@2.5 t ha−1), farmyard manure (FYM@10 t ha−1), crop residue (CR@1.5 t ha−1 of soybean residue during rabi and 3 t ha−1 of mustard residue during kharif season) with recommended fertilizer doses (RNPK) was evaluated in randomized block design with three replications for four consecutive years in soybean-mustard cropping sequences (2016–2019). Results demonstrated that application of gypsum with CR and FYM recorded a significant drop in exchangeable sodium percentage (ESP) (45–48 %), and bulk density (BD) (3–6 %) than that of control. Organic amendment in conjunction with gypsum and chemical fertilizer significantly improved soil chemical, physical and biological properties than that under control and inorganic fertilizer alone treatments. Based on principal component analysis and correlation matrix, minimum data set identified ESP, pH, BD, organic carbon, available nutrients, biomass carbon, calcium content, dehydrogenase as the most important properties controlling soil quality. Integration of RNPK+Gypsum+CR and RNPK+Gypsum+FYM are found superior leading to higher crop yield in soybean (1.23 and 1.21 Mg ha−1 respectively), mustard (1.43 and 1.39 Mg ha−1 respectively), better nutrient recovery efficiency (77 and 53 % respectively), improved soil quality index (0.90 and 0.93 respectively), and higher economic return (benefit: cost ratio-2.88 and 2.1 respectively).Therefore, this study findings highlighted the conjunctive use of gypsum with organic amendments is effective in reclaiming salt stress, improving soil health and crop productivity under oilseed cropping sequence in degraded soils of semi-arid tropics.

Development of a parametric-based Analytical Hierarchy Process (AHP) utilizing Geographic Information Systems (GIS) for wheat land suitability evaluation

Wheat is considered one of the most essential crops for Egypt. Nevertheless, it is also one of its largest imports. Therefore, it is important to develop an accurate wheat suitability model to define the most suitable areas for its production. This study aimed to develop a parametric-based Analytical Hierarchy Process (AHP) using Geographic Information Systems (GIS) for land suitability evaluation of wheat in a selected area in El-Beheira governorate, Egypt. The climatic and land parameters influencing wheat production in the studied area were selected and rated according to the parametric method. These parameters included slope, texture, calcium carbonate, sum of basic cations, pH, organic matter, salinity, exchangeable sodium percentage and mean temp. of the growing cycle. The rated parameters were processed according to the AHP. The results were compared with Storie and the Square root methods and field observations. When validated using field observations, the developed method had a higher accuracy suitability evaluation for wheat cultivation in the studied area than the other two methods. According to the developed method, almost all of the studied areas could be classified as very suitable (S1) for wheat cultivation. On the other hand, the wheat suitability evaluation according to the other two methods indicated that most of the studied area could be classified as moderately suitable (S2) and marginally suitable (S3), which contradicted the field survey.

Fertility and heavy metal pollution in silage maize soil irrigated with different levels of recycled wastewater under conventional and no-tillage practices

AbstractIrrigation with recycled domestic wastewater has been known to obtain positive effects on improving soil fertility, but it may also become a risk factor in case of causing an increase in soil salinity and/or heavy metal concentration of soil. No-tillage can retain soil moisture, helping to reduce irrigation water necessity, and thus lower amounts of heavy metals and salts are added to soil under wastewater irrigation conditions. The objective of this study was to analyze the effects of wastewater irrigation at different levels of on silage maize cultivation under conventional tillage and no-tillage conditions by comparing to full irrigation with fresh water. The two-year experiment was planned according to the split-plots design in the random blocks with three replications. The results indicated that full irrigation with wastewater increased soil salinity, organic matter content, total nitrogen, plant available phosphous, exchangeable cations, exchangeable sodium percentage and soil essential and non-essential heavy metal contents, but decreased soil pH and lime content. Increasing rates in organic matter content, total nitrogen, plant available phosphorus and exchangeable potassium were higher, but in electrical conductivity, and heavy metal accumulation were lower in soil under no-tillage as compared to conventional tillage. Contamination and enrichment factors and geographic accumulation index showed that non-essential heavy metal contamination due to cadmium and nickel, increased in full irrigation with wastewater. Irrigation with wastewater also increased heavy metal accumulation in silage maize. No-tillage can be a recommendable water management practice considering that the risks of soil salinity and heavy metal accumulation can be reduced and that soil fertility can be increased. Also, in reducing the risk of accumulation of cadmium and nickel in soil, 33% deficit irrigation with wastewater can make no-tillage more available.

Assessment of Soil Quality of Smallholder Agroecosystems in the Semiarid Region of Northeastern Brazil

The assessment of soil quality is crucial for the sustainable development of agriculture in semiarid regions. Due to their sensitivity to management practices, soil chemical and physical quality indicators are used for investigating soil quality. This study aimed to assess the soil quality of smallholder agroecosystems from the Brazilian semiarid region. Soil physical and chemical attributes were screened using principal component analysis (PCA) and integrated into a weighted additive soil quality index (SQI). Soil quality was obtained using linear and non-linear scoring methods, a total data set (TDS), and a minimum data set (MDS). The soil quality of the agroecosystems was designated as being of moderate grade. The MDS for soil quality assessment includes cation exchange capacity, C stock, exchangeable sodium percentage, flocculation degree, pH, electrical conductivity, available P, and K+ from twenty-five indicators of the TDS. This MDS mainly reflects the input of manure and crop residues associated with moderate weathering of easily weatherable minerals given the semiarid conditions. The SQI obtained can be used to synthesize the information of the TDS and is a valuable tool to indicate the soil quality of agroecosystems; thereby, it can be used with indicators of sustainable management for application at a regional scale.

MAPPING THE SALINITY STATUS OF AGRICULTURAL SOILS BETWEEN KIRIKHAN-KUMLU IN THE EASTERN MEDITERRANEAN REGION OF TURKEY WITH GEOGRAPHIC INFORMATION SYSTEMS (GIS)

In this study, it was aimed to determine the salinity status of agricultural soils between Kırıkhan-Kumlu in the Eastern Mediterranean region of Turkey by mapping with Geographic Information Systems (GIS). For this purpose, a total of 60 soil samples were taken from 0–20 and 20–40 cm depths and from 30 different points to represent the agricultural soils of Kırıkhan-Kumlu region in the Eastern Mediterranean region of Turkey. In the soil samples, pH, cation exchange capacity (CEC) and exchangeable cation (ECC) values were determined to determine some soil properties. Total salt, salinity class, sodium adsorption rate (SAR), exchangeable sodium percentage (ESP) and soluble cations (Na, Ca and Mg) were determined to determine the salinity status of the soils. According to the results of the research; as a result of the analysis carried out to determine the salinity status of the soils; pH values were determined between 6.91–7.98; total salt content between 0.02–0.13%; SAR values between 0.023–0.044 me/100 gr; ESP values between 0.35–2.96%; soluble Na content between 0.019–0.034 me/100 gr; soluble Ca content between 0.018–0.245 me/100 gr and soluble Mg content between 0.037–0.113 me/100 gr. In addition, by applying the ESP-SAR regression relationship of the soils, it was revealed that the soils tended to alkalize towards the lower layers. The salinity values obtained as a result of the study were transferred to the Geographic Information Systems (GIS) environment and interpolated by Kriging method and a salinity map of the study area was created. In conclusion, as a result of the research conducted in the soils of the study area in the Eastern Mediterranean region, it was determined that all of the agricultural soils of Kırıkhan-Kumlu region were classified as non-saline and that the soils did not have any problems in terms of salinity.

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

AbstractSoil 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.

Biochar Application Reduces Saline–Alkali Stress by Improving Soil Functions and Regulating the Diversity and Abundance of Soil Bacterial Community in Highly Saline–Alkali Paddy Field

Saline–alkali soils seriously restrict the soil functions and the growth and diversity of soil microorganisms. Biochar can alleviate the negative effects of saline–alkali stress. However, it remains unclear how biochar reduces saline–alkali stress by improving soil functions and regulating the abundance and diversity of the soil bacterial community in highly saline–alkali paddy fields. To address this, a paddy field experiment was conducted in a highly saline–alkali paddy field using two nitrogen application levels (0 and 225 kg ha−1) and four biochar application rates (0, 1.5%, 3.0%, and 4.5% biochar, w/w). The results show that, compared with C0, biochar application, especially when combined with N fertilizer, significantly decreased the soil pH, exchangeable sodium percentage (ESP), saturated paste extract (ECe), and sodium adsorption ratio (SAR) while significantly increasing cation exchange capacity (CEC). These indicated that biochar can effectively reduce saline–alkali stress. Biochar application significantly increased soil content of total nitrogen (TN), alkali-hydrolysable N (AN), available P (AP), available K (AK), soil organic matter (SOM), and soil C/N ratio, both with or without N fertilization. Furthermore, biochar application further increased the relative abundance of bacterial communities and modified the bacterial community structure in highly saline–alkali paddy soils. Under C3N2, C2N2, and C1N2, Chao1 increased by 10.90%, 10.42%, and 1.60% compared to C0N2. Proteobacteria, Bacteroidetes, and Chloroflexi were the top three phyla in bacterial abundance. Biochar significantly increased the abundance of Proteobacteria while reducing Bacteroidetes and Chloroflexi, regardless of N fertilization. Correlation analysis results showed that the improvements in soil chemical and saline–alkali properties, as well as nutrient bioavailability after biochar application, had a positive effect on bacterial communities in highly saline–alkali paddy soils.

Impact of cellulose and lignin on restoration of vegetation and soil chemical properties for saline-alkali soil of songnen plain.

To explore the effects of cellulose and lignin on stimulating vegetation restoration and improving soil chemical properties in saline-alkali soil, a large area test was carried out, and 2 treatments were set up: T (cellulose and lignin+ Planted seeds) and CK (Planted seeds). In this study, the species, quantity, plant height, above-ground biomass, biodiversity of vegetation in the treated plots, the determination of soil chemical nutrient content, and the effect of cellulose and lignin on vegetation restoration in saline-alkali land were investigated. The results showed that: 1) Cellulose and lignin contributed to vegetation growth. Compared with CK treatment, plant height and aboveground biomass of T increased by 158.73% and 240.13%, respectively; 2) Cellulose and lignin improved soil structure, and soil porosity, and decreased soil compaction (21.95%); 3) Compared with CK treatment, T treatment decreased soil pH by 0.5 units, total salt content decreased by 30.95%, exchangeable Na+ decreased by 63.00%, and exchangeable sodium percentage (ESP) decreased by 61.51%. Furthermore, cellulose and lignin effectively improved the physical and chemical properties of saline-alkali soil, promoted the recovery of ecological environment in saline-alkali soil, and improved regional biodiversity, which will provide new methods for soil remediation and improvement in saline-alkali areas.

Effect of biochar addition on water–salt distribution and growth of winter wheat in coastal saline‐alkali soils under brackish water irrigation

AbstractTo investigate water‐saving and yield‐enhancing improvement programmes suitable for saline‐alkali soils in the Yellow River Delta region, this study conducted outdoor pot experiments utilizing local moderately saline‐alkali soils as research subjects. The primary focus was to examine the impact of biochar addition on water and salt distribution in saline‐alkali soils and its effect on winter wheat growth under brackish water irrigation conditions. The study design established three different irrigation water mineral concentrations (0, 2 and 4 g L−1) during the research. Two types of biochar, wheat straw biochar (WB) and corn straw biochar (CB), were used with four different applications (0, 5, 10 and 20 t ha−1). There were 21 treatments; each replicated three times. These findings demonstrated that brackish water irrigation and biochar application contributed to a notable increase in soil water content (SWC), with increases ranging from 12.8 to 83.9% across treatments. Using brackish water for irrigation increases soil salt content (SSC) and exacerbates soil salinization. However, the application of biochar counteracts this effect by reducing soil salinity and mitigating the degree of salinization. Treatments applying biochar mostly increased SSC, but proper application had a salinity‐reducing effect, reducing SSC by up to 15.2%. And biochar reduced the soil sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP), mitigating the adverse effects of high salinity on winter wheat. Finally, the application of biochar promoted the growth of winter wheat and increased yield, with the treatment applying 10 t ha−1 of CB (K2Y10) producing the greatest yield under brackish water irrigation conditions and increased by 18% compared with the treatment without biochar (CK0). In summary, considering the aspects of water conservation, salt reduction and yield increase, the most effective saline land improvement programme for this region involved using 2 g L−1 brackish water for irrigation in combination with applying K2Y10. This approach balances addressing soil salinity, enhancing water conservation and maximizing crop yields.

Municipal solid waste compost use can improve crop barley production and enhance soil chemical fertility

The study aims to point out the effect of municipal solid waste compost (MSWC) and traditional mineral fertilizers use, on rainfed forage barley herbage and grain production, nutritive value, and on soil chemical characteristics. During a three-year field trial, the MSWC treatments were COM1, 20 Mg ha−1 (DM) applied each year; COM2, 20 Mg ha−1 applied only the first year. The mineral fertilization was MIN50 (50 kg ha−1 of N + 46 kg ha−1 of P2O5), and MIN100 (100 kg ha−1 of N + 92 kg ha−1 of P2O5), applied each year. Fertilization treatments were compared with unfertilized control (COM0 and MIN0). Two years out of three COM1 showed a significant higher barley herbage dry matter (HDM) production and CP, when compared to COM0. COM1 in one year increased grain yield (YLD) whereas increased CP all years and decreased starch grain content two years out of three. MSWC strongly increased levels of sodium (Na) in herbage and grain. Mineral fertilizers levels significantly increased HDM production and YLD and their CP content compared to MIN0. Moreover, it lightly decreased herbage NDF, ADF, WSC and Total phenols content, raising in vitro dry matter digestibility (IVDMD). In soil, after three years of fertilization, COM1 increased SOC (Soil Organic Carbon), Total N, available P, exchangeable K and Mg content, but also exchangeable sodium percentage (ESP) and electrical conductivity (EC), showing higher values than COM2 and COM0. Mineral fertilization influenced only the available P soil level, increasing the content compared to MIN0. This paper pointed out that mineral fertilizers had clear short-term effects on the barley growth, yield, and nutritional value, but did not contribute to soil long-term fertility improvement. MSWC increased barley growth and yield reaching similar values obtained with mineral fertilizers. Above all, MSWC showed capability to improve soil fertility mainly in terms of organic matter and macronutrients and its use is consistent with the recent EU regulation on organic fertilizer productions (2018/84) that aims to “maintaining the long-term fertility of soils”.

Pedological Investigation of Soil Quality Indicators in Tapioca Growing Soils

Background: Manihot esculenta, the most important tropical root crop which supply dietary staple food for about 800 million populations worldwide. Twenty soil profiles that represent the soil Pedology and soil quality are similar in their concept in relation to soil formation. In this regards, soil quality can be considered as part of the science of pedology. Significant differences in yield of Tapioca (Manihot esculenta) with selected soil properties and subsequent interpretations as influenced by land use are explained. Methods: Soil samples were taken from designated pedogenic horizons for physico-chemical properties in the laboratory. Soil textural class, saturated hydraulic conductivity, Cation Exchange Capacity, Base Saturation Percentage, soil organic carbon, exchangeable cations, available N, P, K content and available micronutrients were analysed. The general fertility of the soils in the area is discussed highlighting their potentials and constraints. Result: A comprehensive analysis of soils in the study area showed that shallow soil depth of less than 47 cm and more clay of 44% with high bulk density of 1.4 gcc-1, low hydraulic conductivity of 0.12 cmhr-1, low base saturation percentage of 77%, more exchangeable sodium percentage of 7.96% with low available N, P and K of 110, 10.75 and 142.25 kg ha-1, respectively in low yielding soils are the major constraints in the tract might behind the yield differences in Cassava.

Ameliorative Effect of Different Amendments on Nutrients Availability in Sodic Soils

A pot house experiment was conducted at the Net House, Regional Research Station, AAU, Anand during rabi season of 2018-19 on Wheat (GW-496) as a indicator crop. Total four amendments i.e. A0(control), A1(Gypsum @ 50% GR), A2(Vermi-compost @ 4.0 t ha-1) and A3 (sulphur @ 50 kg ha-1) and six soils type (S1 to S6) were selected under Factorial CRD. Pot study results indicated that the soil amendments significantly decreased the pH, EC and ESP of sodic soils. The order of decrease in pH of sodic soils from 8.75 to 7.89 by application of amendments remained as: vermin-compost &gt; sulphur &gt; gypsum. The EC of sodic soils significantly decreased due to application of vermin-compost and gypsum by 20.48% and 10.84%, respectively over control. The application of vermin-compost, gypsum and sulphur significantly lowered down Exchangeable Sodium Percentage (ESP) from 18.45 to 12.44, 13.00 and 13.57, respectively, and the effect of gypsum was found at par with sulphur in decreasing soil ESP. Application of vermin-compost (4.0 t ha-1) significantly influenced CEC (28.28 Cmol (P+) kg-1) over control (no amendment). Irrespective of amendments, soil S5 recorded the highest pH (8.39), EC (0.92 dSm-1), ESP (16.48) and the lowest was in soil S6 (pH 7.99, EC 0.64 dSm-1). The interaction of soil x amendment treatments showed significant effects on pH, EC and ESP of sodic soils. The application of amendments showed significant effect on available nutrients in soil after harvest of wheat and the highest OC (0.73%), available P2O5 (65.71 kg ha-1), available K2O (207.1 kg ha-1) content in soil was recorded when vermin-compost applied at 4.0 t ha-1 followed by sulphur at 50 kg ha-1 and gypsum at 50% GR but available S (16.33 mg kg-1) was recorded the highest due to sulphur application at 50 kg ha-1 followed by gypsum and vermi-compost.