Saline-alkali Soil Research Articles

Effects of Male and Female Strains of Salix linearistipularis on Physicochemical Properties and Microbial Community Structure in Saline-Alkali Soil.

The woody plant gender difference may lead to alteration in rhizosphere microbial communities and soil physicochemical properties. In this study, we investigated the differences in rhizosphere soil properties and microbial community structures of S. linearistipularis. Rhizosphere microorganisms were analyzed by high-throughput sequencing technology. The results showed that there were significant differences in rhizosphere soil nutrition between male and female S. linearistipularis plants in saline-alkali soil. The female S. linearistipularis plants significantly reduce soil pH values and significantly increase the soil water content (SWC), available total nitrogen (TN), soil organic matter (SOM), and soil urease activity (S-UE) compared to the male plant. The ACE, Chao, and Shannon index of the female plant was significantly higher than that of the male strain. At the level of Bacteriophyta, the relative abundance of Actinobacteriota in male and female S. linearistipularis was the highest, with 34.26% and 31.03%, respectively. Among the named bacterial genera, the relative abundance of Defluviicoccus of male and female plants was the highest, with 2.67% and 5.27%, respectively. At the level of Eumycophyta, the relative abundance of Ascomycetes in male and female plants was the highest, with 54.93% and 52.10%, respectively. Among the named fungi genera, the relative abundance of male and female plants of Mortierella was the highest, with 6.18% and 9.31%, respectively. In addition, soil pH, SOM, SWC, and S-UE activities were the main driving factors of soil microbial community structures. In the process of restoring saline-alkali land in the Songnen Plain, we may prioritise the planting of female S. linearistipularis, which also provides a theoretical basis for the microorganisms restoration of saline-alkali land in the Songnen plain.

Arbuscular Mycorrhizal Fungi Restored the Saline-Alkali Soil and Promoted the Growth of Peanut Roots.

Peanut (Arachis hypogaea L.) is an important oil and cash crop. An efficient utilization of saline-alkali soil resources, the development of peanut planting in saline-alkali soil, and obtaining high and stable yield have become urgent needs to ensure peanut production. Arbuscular mycorrhizal fungi (AMF) have been reported to develop the potential productivity of host plants and improve their salt resistance and tolerance. However, there is still limited research on promoting the growth and morphology of peanut roots. Therefore, in this study, seeds of salt-tolerant peanut variety "HY 25" were coated with commercial AMF inoculant before being planted in saline-alkali and normal soils to investigate the effects of AMF on peanut root growth and rhizosphere soil. The results showed that root morphological characteristics were significantly increased by the use of AMF at the podding stage in saline-alkali soil and from the flowering and pegging stage to the maturity stage in normal soil. Of note, the total root volume of peanut inoculated with AMF significantly increased by 31.57% during the podding stage in saline-alkali soil. Meanwhile, AMF significantly increased the phosphatase and invertase activities in the peanut rhizosphere of saline-alkali soil from the flowering stage to maturity stage and soil CAT activity at the maturity stage (41.16~48.82%). In normal soil, soil phosphatase and urease activities were enhanced by AMF at the flowering stage and the podding stage, respectively. AMF also increased the contents of soil organic matter, available phosphorus, and hydrolysable nitrogen, but decreased soil EC in saline-alkali soil. In addition to the significant increase in soil available phosphorus content, AMF had no significant effect on the physical and chemical properties of the soil and other soil nutrients in normal soil. AMF significantly increased pod biomass and yield in saline-alkali soil and normal soil, and improved their agronomic characteristics. In conclusion, peanut seeds coated with AMF improved the root morphological characteristics of peanuts and improved the physical and chemical properties in peanut rhizosphere, especially in saline-alkali soil. The process of rhizosphere soil nutrient transformation was also enhanced. Finally, AMF improved plant agronomic traits to increase the pod yield (16.5~21.9%). This study provides the theoretical basis and technical support for the application of AMF in peanut production in saline-alkali soil.

Comparative Na+ and K+ Profiling Reveals Microbial Community Assembly of Alfalfa Silage in Different Saline-Alkali Soils

Alfalfa cultivated in saline-alkaline soils exhibits a high buffering capacity but low carbohydrate content, posing challenges in the production of high-quality silage feed. This study investigated alfalfa plants grown under varying conditions: mild (QE, salt content 1–2%), moderate (ZE, salt content 2–3%), severe (HE, salt content 3–4%), and non-saline-alkaline (CON, salt content < 1%). Employing a two-factor experimental design, we analyzed the fluctuations in nutritional quality, microbial abundance, and community composition of different salt–alkaline alfalfa materials and silage feeds. Furthermore, we elucidated the fermentation mechanism involved in salt–alkaline alfalfa ensiling. Following a 60-day ensiling period, the ZE and HE treatments led to substantial reductions in pH, acetic acids (AA), branched-chain butyric acids (BA) content, facultative anaerobic bacteria, and Escherichia coli populations (p < 0.05). Conversely, the ZE and HE treatments increased lactic acid (LA) content and the population of lactic acid bacteria (LAB) (p < 0.05). Additionally, these treatments significantly mitigated protein losses in both raw alfalfa and silage feeds (p < 0.05), while remarkably augmenting the water-soluble carbohydrates (WSC), Na+, and K+ content of alfalfa materials. Sodium ions were found to exert a considerable influence on bacterial community composition during salt–alkaline alfalfa ensiling, with Enterococcus, Lactococcus, and Lactobacillus identified as the predominant fermentative microorganisms. Overall, moderately salt-alkaline alfalfa materials displayed optimal nutritional and fermentation quality, ensuring favorable nutritional attributes and fermentation outcomes under such conditions.

Effects of compost as a soil amendment on bacterial community diversity in saline-alkali soil.

Soil salinization poses a worldwide challenge that hampers agricultural productivity. Employing high-throughput sequencing technology, we conducted an investigation to examine the impact of compost on the diversity of bacterial communities in saline soils. Our study focused on exploring the diversity of bacterial communities in the inter-root soil of plants following composting and the subsequent addition of compost to saline soils. Compared to the initial composting stage, Alpha diversity results showed a greater diversity of bacteria during the rot stage. The germination index reaches 90% and the compost reaches maturity. The main bacterial genera in compost maturation stage are Flavobacterium, Saccharomonospora, Luteimonas and Streptomyces. Proteobacteria, Firmicutes, and Actinobacteria were the dominant phyla in the soil after the addition of compost. The application of compost has increased the abundance of Actinobacteria and Chloroflexi by 7.6 and 6.6%, respectively, but decreased the abundance of Firmicutes from 25.12 to 18.77%. Redundancy analysis revealed that soil factors pH, solid urease, organic matter, and total nitrogen were closely related to bacterial communities. The addition of compost effectively reduced soil pH and increased soil enzyme activity and organic matter content. An analysis of this study provides theoretical support for compost's use as a saline soil amendment.

Effects of biochar amendment and organic fertilizer on microbial communities in the rhizosphere soil of wheat in Yellow River Delta saline-alkaline soil.

The biochar and organic fertilizer amendment have been used as an effective practice to increase soil fertility. Nevertheless, the mechanisms of microbial community response to organic fertilizer and biochar application on saline-alkali soil have not been clarified. This study investigated the effects at different concentrations of organic fertilizer and biochar on the microbial community of wheat rhizosphere soil under field experiment in the Yellow River Delta (China, YRD), using high-throughput sequencing technology. Biochar and organic fertilizer significantly influenced in most soil parameters (p < 0.05), apart from soil moisture content (M), pH, total nitrogen (TN) and soil total phosphorus (TP). Proteobacteria and Actinobacteriota were found in the rhizosphere soil as the main bacterial phyla, and the main fungal phyla were Ascomycota and Mortierellomycota. The soil bacterial and fungal communities under organic fertilizer were distinct from CK. Furthermore, redundancy analysis (RDA) directed that changes in bacterial communities were related to soil properties like pH, available phosphorus (AP), and total organic carbon (TOC), while pH, AP and TP, were crucial contributors in regulating fungal distribution. The correlation between soil parameters and bacteria or fungi varied with the application of biochar and organic fertilizers, and the interaction between the bacteria and fungi in organic fertilizer treatments formed more connections compared with biochar treatments. Our results indicated that biochar was superior to organic fertilizer under the contents set up in this study, and soil parameters increased with biochar and organic fertilizer application rate. The diversity and structure of soil bacteria and fungi differed with the application of biochar and organic fertilizer. The research provides a reference to rational application of organic fertilizer and biochar improvement in saline-alkali soil.

Study On the Application of Nitro-Compound Fertilizer to Improve Saline-Alkali Soil

The deterioration of soil quality in saline-alkali land has always been a major problem restricting the development of agriculture in China. Therefore, this study studied the application effect of nitro-compound fertilizer through experiments, aiming to explore the application prospect and popularization value of nitro-compound fertilizer in saline-alkali land agriculture. The experimental results showed that nitro-compound fertilizer could significantly improve the soil quality and increase the yield and growth of crops in saline-alkali soil. The addition amount of 2.5-10 kg/ mu is more suitable, and the addition of 10 kg/ mu of nitro-compound fertilizer can increase the yield of corn by 217%. In addition, the addition of nitro-compound fertilizer can not only significantly reduce the soil salt content, the reduction can reach 37.5%, but also significantly improve the soil alkalinity. pH value decreased from the original 9.4 to 7.12, a decrease of 2.28. This showed that the application of nitro-compound fertilizer had a remarkable improvement effect in regulating soil alkalinity. Therefore, the application of nitro-compound fertilizer has wide application prospect and popularization value in saline-alkali land agriculture.

Manipulating rhizosphere microorganisms to improve crop yield in saline-alkali soil: a study on soybean growth and development.

Rhizosphere microorganisms can effectively promote the stress resistance of plants, and some beneficial rhizosphere microorganisms can significantly promote the growth of crops under salt stress, which has the potential to develop special microbial fertilizers for increasing the yield of saline-alkali land and provides a low-cost and environmentally friendly new strategy for improving the crop yield of saline-alkali cultivated land by using agricultural microbial technology. In May 2022, a field study in a completely randomized block design was conducted at the Heilongjiang Academy of Agricultural Sciences to explore the correlation between plant rhizosphere microorganisms and soybean growth in saline-alkali soil. Two soybean cultivars (Hening 531, a salt-tolerant variety, and 20_1846, a salt-sensitive variety) were planted at two experimental sites [Daqing (normal condition) and Harbin (saline-alkali conditions)], aiming to investigate the performance of soybean in saline-alkali environments. Soybeans grown in saline-alkali soil showed substantial reductions in key traits: plant height (25%), pod number (26.6%), seed yield (33%), and 100 seed weight (13%). This underscores the unsuitability of this soil type for soybean cultivation. Additionally, microbial analysis revealed 43 depleted and 56 enriched operational taxonomic units (OTUs) in the saline-alkali soil compared to normal soil. Furthermore, an analysis of ion-associated microbes identified 85 mOTUs with significant correlations with various ions. A co-occurrence network analysis revealed strong relationships between specific mOTUs and ions, such as Proteobacteria with multiple ions. In addition, the study investigated the differences in rhizosphere species between salt-tolerant and salt-sensitive soybean varieties under saline-alkali soil conditions. Redundancy analysis (RDA) indicated that mOTUs in saline-alkali soil were associated with pH and ions, while mOTUs in normal soil were correlated with Ca2+ and K+. Comparative analyses identified significant differences in mOTUs between salt-tolerant and salt-sensitive varieties under both saline-alkali and normal soil conditions. Planctomycetes, Proteobacteria, and Actinobacteria were dominant in the bacterial community of saline-alkali soil, with significant enrichment compared to normal soil. The study explored the functioning of the soybean rhizosphere key microbiome by comparing metagenomic data to four databases related to the carbon, nitrogen, phosphorus, and sulfur cycles. A total of 141 KOs (KEGG orthologues) were identified, with 66 KOs related to the carbon cycle, 16 KOs related to the nitrogen cycle, 48 KOs associated with the phosphorus cycle, and 11 KOs linked to the sulfur cycle. Significant correlations were found between specific mOTUs, functional genes, and phenotypic traits, including per mu yield (PMY), grain weight, and effective pod number per plant. Overall, this study provides comprehensive insights into the structure, function, and salt-related species of soil microorganisms in saline-alkali soil and their associations with salt tolerance and soybean phenotype. The identification of key microbial species and functional categories offers valuable information for understanding the mechanisms underlying plant-microbe interactions in challenging soil conditions.

Effective strategies for reclamation of saline-alkali soil and response mechanisms of the soil-plant system

The combination of amendments has emerged as a potential strategy to efficiently alleviate salt stress in saline-alkali soil. However, knowledge regarding how to optimize the proportion of different amendment materials, comprehensively assess the contribution of each component, and clarify the response mechanisms of the amendment-saline-alkali soil-plant system is incomplete. Based on this, we conducted a pot experiment to evaluate the improvement effect of the combined application of different amendment materials at varying levels and the contribution of the amendment components to alleviating salt stress. Overall, T6 exhibited the most significant improvement effect on the physicochemical and biological properties of the saline-alkali soil and promoted the growth of oilseed rape, with the levels of 2.0 % phosphogypsum, 2.0 % humic acid, 0.25 % bentonite, and 0.03 % sodium carboxymethyl cellulose. Compared with the control group, the EC decreased by 1.51 % to 33.49 %, the soil salt content dropped by 11.40 % to 35.46 %, and the soil soluble Na + concentration significantly declined by 39.47 % to 63.20 %. Additionally, the soil nutrient content and soil microbial community structure were enhanced in treatment groups. Meanwhile, amendments alleviated salt stress in the oilseed rape plant by activating anti-oxidative enzymes and osmoregulatory substances such as soluble sugar and proline, thus improving their ability to remove reactive oxygen species (ROS). The anti-oxidative enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly increased, with an increase of 10.68 % (SOD, T2) ∼207.31 % (CAT, T6) compared to the control group. The structural equation modeling (SEM) analysis and simulation experiments indicated that the amendment components synergically promoted the amelioration effect on salt stress, and effectively improved soil properties, which affected the response of oilseed rape to soil environment. This research paper provides the relevant reference for the combined application of different amendment materials for soil reclamation.

Optimizing biochar application rates for improved soil chemical environments in cotton and sugarbeet fields under trickle irrigation with plastic mulch

Biochar can potentially change the soil physico-chemical environment significantly, but its impact on the soil chemical environment is poorly understood. To investigate this, a three-year field experiment with drip irrigation under plastic film mulch was conducted from 2018 to 2020 in a saline-alkali cotton and sugarbeet field in Xinjiang, China. The experiment examined the influences of different biochar application rates (BAR) on the distribution and variations of soil Na+ and K+ contents, soil nutrient contents (NO3–-N, NH4+-N, soil organic carbon, available phosphorus, and available potassium), soil salt content and accumulation. Four BAR treatments of 0, 10, 50, and 100 t ha–1, namely CK, B10, B50, and B100 were designed in 2018, with adjusted in 2019 and 2020 based on the former 2 year’s results, namely CK, B10, B25 (25 t ha–1), B50, and B100 in 2019, and CK, B10, B25, and B30 (30 t ha–1) in 2020. The results indicated that increasing BAR significantly increased Na+, K+, and soil nutrient contents in cotton and sugarbeet fields. Soil salinity were the highest in inter-rows, followed by narrow and wide rows, and salt accumulated at 0–60 cm depth the most. Weighted-average planar soil salt storage positively correlated with BAR, with lower soil salt contents for sugarbeet than cotton at the same depth. Based on the effects of different BAR on soil ion concents, soil nutrients, and soil salinity, we recommended 10 t ha−1 as an optimal BAR for improving the chemical environment of saline-alkali soil, and sugarbeet as an effective crop for reducing soil salinity. These findings provided valuable technique parameters for biochar application in saline-alkali land.

Impacts of various amendments on the microbial communities and soil organic carbon of coastal saline-alkali soil in the Yellow River Delta.

The utilization of industrial and agricultural resources, such as desulfurization gypsum and straw, is increasingly favored to improve saline alkali land. However, there is still a lack of comprehensive study on the mechanism of organic carbon turnover under the conditions of desulfurization gypsum and straw application. We studied the changes in soil chemical performance, microbial diversity, and microbial community structure in soils with the addition of various levels of straw (no straw, S0; low straw, Sl; medium straw, Sm; and high straw, Sh) and gypsum (no gypsum, DG0; low gypsum, DGl; and high gypsum, DGh) in a 120-day incubation experiment. The bacterial and fungal community richness was higher in the SmDGl treatment than in the SmDG0 treatment. The microbial community evenness showed a similar pattern between the SmDGl and SmDG0 treatments. The combination of the straw and desulfurization gypsum treatments altered the relative abundance of the main bacterial phyla Bacteroidetes and Firmicutes and the dominant fungal class Sordariomycetes, which increased with the enhancement of the SOC ratio. The combination of the straw and desulfurization gypsum treatments, particularly SmDGl, significantly decreased the soil pH and exchangeable sodium percentage (ESP), while it increased the soil organic carbon, microbial biomass carbon, and activities of soil enzymes. Improvement in the soil salinization environment clearly drove the changes in bacterial α-diversity and community, particularly those in the soil carbon fractions and ESP. In conclusion, these findings provide a strong framework to determine the impact of application practices on soil restoration, and the information gained in this study will help to develop more sustainable and effective integrated strategies for the restoration of saline-alkali soil.

Intercropping of Echinochloa frumentacea with Leguminous Forages Improves Hay Yields, Arbuscular Mycorrhizal Fungi Diversity, and Soil Enzyme Activities in Saline–Alkali Soil

Soil salinization is detrimental to crop growth, agricultural yields, and environmental protection. Echinochloa frumentacea (Roxb.) Link is a pioneer species for the alteration of saline–alkali lands. In this paper, we examined the effects of intercropping between E. frumentacea and leguminous forages on saline land improvement in the saline–alkali soil of the Hetao-Ningxia Plain, China. We found that intercropping increased the diversity and richness of the arbuscular mycorrhizal fungi (AMF) community in the rhizosphere soil of E. frumentacea. Glomus was the dominant genus in the saline–alkali soil of the Hetao-Ningxia Plain, where Glomeraceae, VTX00067, VTX000193, and VTX000165 were the dominant species. Intercropping improved the activities of soil urease, sucrase, alkaline phosphatase, and catalase. The hay yields of E. frumentacea were correlated positively with soil enzyme activities, Chao1 index, and ACE index, and negatively with total water-soluble salt content. Together, intercropping between E. frumentacea and leguminous forages enhances AMF diversity and soil enzyme activities, which provides an agricultural practice for improving sustainability of the agro-ecosystem in saline–alkali areas.

Effects of Common Biochar and Acid-Modified Biochar on Growth and Quality of Spinach in Coastal Saline Soils.

The rational development and efficient utilization of saline soils can alleviate the problem of insufficient arable land faced by agricultural production in China. A prominent problem is improving soil salt and water conditions for promoting land resources' productivity in coastal areas. Biochar is widely used for soil improvement, as it has remarkable properties. A pot experiment was conducted to study the effects of two kinds of biochar (common biochar and acid-modified biochar) with three addition rates (2%, 4%, and 8%) on the growth, yield, photosynthetic characteristics, and quality of spinach. The results revealed that 2% and 4% common biochar increased the plant height, stem diameter, and leaf area index, effectively improving the yield of spinach and water productivity, while 8% common biochar was detrimental to the growth of spinach to some extent. Acid-modified biochar significantly benefited the growth and increased the water productivity of spinach, ensuring high yields, while also improved quality. Similarly, acid-modified biochar was less effective at high additions than at low-to-medium additions. The integrated biological response version 2 (IBRV2) values under acid-modified biochar treatments were all significantly higher than those under common biochar, but there is no significant difference among three treatments in the same biochar group, which suggested a pronounced amelioration in spinach growth within saline-alkali soil upon the incorporation of acid-modified biochar. Overall, applying acid-modified biochar at the rate of 4% exhibited enormous potential for increasing the yield and quality of spinach in saline soils.

Wax bayberry is a suitable rootstock for Chinese red bayberry cultivated in saline-alkali soil

Wax bayberry or wax myrtle, Morella cerifera L., (MC) is a member of the Myricaceae family and belongs to the same genus as Chinese red bayberry (Morella rubra) (MR). It is an evergreen shrub native to Pennsylvania, USA, and is resistant to saline-alkali stress. China has a large area of saline-alkali soil in the south-eastern coastal regions, and this study aimed to evaluate the suitability of MR cv ‘Biqi’ grafting on MC for cultivation on saline soil. This MC rootstock tolerated stress in soil with high sodium, magnesium and calcium concentrations with no toxicity symptoms. Trees of cv ‘Biqi’ grafted on MC grew normally in saline-alkali soil, with dark green leaves, high chlorophyll content and healthy appearance, while the trees grafted on MR suffered severe chlorosis in saline alkali soil. The average fruit weight of the ‘Biqi’ cultivar grafted on MC in saline alkali soil steadily increased over the 2016–2018 period, and were larger in size and higher in sucrose and citric acid content than those on the MR rootstock grown in either coastal or mountainous areas. The bayberry grafted on MC rootstock also tended to flower and set fruit 1–2 years earlier than that grafted on MR rootstock. High compatibility between the scion (MR) and rootstock (MC) was observed in the microscopic section of the grafting interface. Thus, wax bayberry was considered an effective rootstock for the cultivation of red bayberry in saline-alkali soils.

Integration of Sentinel–1 and Landsat–8 data for identifying deformation risk of hydraulic engineering in seasonally frozen salinization regions

Hydraulic engineering has positive effects on agricultural production and soil desalination. However, freeze–thaw cycles can cause instability in canal slopes, emphasizing the need for effective deformation monitoring. Using Sentinel-1B data acquired from November 2017 to August 2019 and applying the small baseline subset (SBAS) InSAR method, two unstable canal segments with vertical deformation rates exceeding –40 mm/year were identified in Songyuan, Northeast China. The canal slopes uplifted in winter and experienced accelerated subsidence in spring, with the shady slope experiencing a deformation rate approximately 10 mm/year faster than the sunny slope. Further investigation, integrating Landsat–8 data collected from November 2017 to August 2019, revealed that the shady slope received less thermal radiation than the sunny slope, with an average annual temperature difference on the land surface of approximately 1 ℃. In winter, the saline–alkali soil particles formed a thick unfrozen water film, which, driven by temperature and soil–water gradients, migrated towards the freezing front, froze, and caused soil frost heave. The shady slope experienced longer freezing periods and deeper frozen depths, up to 240 cm, causing more unfrozen water migration and greater uplift deformation than the sunny slope. In spring, as temperature rose, the soil thawed from the surface downward. Notably, the shady slope thawed at a slower rate than the sunny slope, forming a frozen lens near a depth of 100 cm. Frozen lens acted as a barrier for meltwater infiltration, impeding the dissipation of pore water pressure, making the shady slope prone to surface landslides. The integration of multiple data sources is beneficial for identifying deformation risk in hydraulic engineering.

Combined Application of Desulfurization Gypsum and Biochar for Improving Saline-Alkali Soils: A Strategy to Improve Newly Reclaimed Cropland in Coastal Mudflats

This study investigated the effects of combined (mixed) application of desulfurization gypsum and biochar on crop growth and soil properties in the saline-alkali soils of coastal mudflats through indoor pot experiments and eight experimental ameliorant treatments. Among them, CK was the control of newly reclaimed cropland in the study area with no added ameliorator, treatment A was desulfurization gypsum applied alone, and treatment F was biochar applied alone, while treatments B, C, D, and E were set as a combination of desulfurization gypsum and biochar treatments with different ratios, and treatment G was a local multi-year improved farmland soil with no added ameliorator. Additionally, an evaluation index system was established for evaluating the saline-alkali soil improvement in the newly reclaimed cropland. Finally, the improvement effect was evaluated by assessing soil physical and chemical indicators, as well as nutrient and crop growth indicators. Based on the results, the following conclusions were drawn: (1) Desulfurization gypsum and biochar significantly improved the soil physicochemical properties. Both single and mixed application of desulfurization gypsum significantly increased soil Ca2+, SO42−, and Mg2+ contents and significantly reduced soil pH, sodium adsorption ratio, and bulk density. Both single and mixed application of biochar significantly reduced soil bulk density and significantly increased water-soluble K+, field capacity (water-holding capacity), available phosphorus, available potassium, and organic matter contents. (2) Both single and mixed application of desulfurization gypsum and biochar demonstrated effectiveness in promoting crop growth, where the fresh weight, dry weight, plant height, and leaf area of peanut were higher than those of treatments CK and G. Treatment A (desulfurization gypsum 100 g/kg) was the most effective ameliorant treatment, in terms of improving the fresh and dry weight of peanut. Treatment C (desulfurization gypsum 75 g/kg, biochar 20 g/kg) had the most significant effect on peanut plant height and leaf area. (3) After 60 days of planting, the improvement effect of each treatment was ranked as C &gt; A &gt; E &gt; B &gt; D &gt; F &gt; G &gt; CK. The treatments with a desulfurization gypsum–biochar combination and desulfurization gypsum alone had the best improvement effect, followed by the treatment with biochar alone.

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.

Effects of Ionized Water Irrigation on Organic Nitrogen Mineralization in Saline-Alkali Soil in China

The application of ionized water to irrigation, as a new type of water treatment technology, can improve the spatial distribution of water in soil and increase water utilization efficiency, which may affect the microbiological processes involved in nitrogen transformation and alter soil nitrogen supply capability. However, the effects of ionized water technology on soil organic nitrogen mineralization are still in need of further research. In this study, we investigated the soil organic nitrogen mineralization process with four different water additions: non-ionized fresh water (CK), ionized fresh water (DE), non-ionized brackish water (BCK), and ionized brackish water (BDE). By using a short-term laboratory incubation method, we monitored the changes of the inorganic nitrogen concentration in each treatment during the incubation process. We compared the net nitrogen mineralization and nitrogen mineralization rates in different treatments, and fitted the organic nitrogen mineralization process with three models (One-pool model, Special model, and EATM model). We divided the whole incubation process into three periods based on the differences of the organic nitrogen mineralization trends. The results demonstrated that when DE was compared with CK, the net nitrogen mineralization increased by 21.97% and the nitrogen mineralization rate increased by 20.42% in the latter incubation period. When BDE was compared with BCK, the net nitrogen mineralization decreased by 3.63%, and the nitrogen mineralization rate increased by 21.86% in the latter incubation period. When BCK was compared with CK, brackish water irrigation reduced the organic nitrogen mineralization intensity to a certain extent, with the net nitrogen mineralization decreased by 11.62% and the nitrogen mineralization rate decreased by 41.07% in the whole incubation process. When BDE was compared with DE, the net nitrogen mineralization decreased by 30.09% and the nitrogen mineralization rate decreased by 53.39% in the whole incubation process. The simulation model of the soil organic nitrogen mineralization process showed that the special model and EATM model are superior to the One-pool model. This study provides a theoretical basis for the popularization and application of ionized water irrigation in agricultural production.

Vermicompost Combined with Soil Conditioner Improves the Ecosystem Multifunctionality in Saline-Alkali Land

Addressing the challenges posed by Saline-Alkali land holds significant promise for optimizing agricultural resources and fostering sustainable agricultural development in affected areas. This study explores the efficacy of coal-based solid waste soil conditioner and vermicompost as mixed-component soil amendments in varying proportions. Through comprehensive field experiments, we investigate the impact of these amendments on soil physicochemical properties, microbial diversity, and the growth of L. chinensis, a grass species native to saline areas. Our findings reveal that the application of vermicompost-based soil amendments effectively reduced soil conductivity and led to noteworthy improvements in the pH of Saline-Alkali soil. Moreover, these amendments demonstrated a marked capacity to enhance soil organic matter and available nutrients, most notably available phosphorus. Concurrently, the introduced soil amendments exhibited a positive influence on soil microbial diversity. A correlation analysis underscores the pivotal roles of soil pH and organic matter in shifting soil microbial communities. In response to amendments, L. chinensis exhibited varying degrees of growth enhancement, with biomass increments ranging from 6.37% to 19.91%. In summary, vermicompost and soil conditioner can improve Saline-Alkali land by supplementing organic matter and effective nutrients, improving pH and conductivity, and regulating microbial community, so as to realize the restoration and improvement of Saline-Alkali land; the greatest improvement was achieved with soil conditioner and vermicompost application rates of 30,000 kg·ha−1 and 15,000 kg·ha−1, respectively. Our results provide robust support for advocating for the integration of vermicompost-based soil amendments in Saline-Alkali land management strategies.

Organic Amendments promote saline-alkali soil desalinization and enhance maize growth.

Secondary soil salinization in arid and semi-arid regions is a serious problem that severely hampers local agricultural productivity and poses a threat to the long-term sustainability of food production. the utilization of organic soil amendments presents a promising approach to mitigate yield losses and promote sustainable agricultural production in saline-alkali soil. In this study, we established four distinct treatments, chemical fertilizer (CK), humic acid with chemical fertilizer (HA), carboxymethyl cellulose with chemical fertilizer (CMC), and amino acid with chemical fertilizer (AA), to elucidate their respective impacts on the reclamation of saline soil and the growth of maize. The findings of our study reveal notable variations in desalination rates within the 0-40 cm soil layer due to the application of distinct soil amendments, ranging from 11.66% to 37.17%. Moreover, application of amendments significantly increased the percentage of soil macro-aggregates as compared to the CK treatment. Furthermore, HA and AA treatments significantly augmented soil nutrient content (HA: 48.07%; AA: 39.50%), net photosynthetic rate (HA: 12.68%; AA: 13.94%), intercellular CO2 concentration (HA: 57.20%; AA: 35.93%) and maize yield (HA:18.32%; AA:16.81%). Correlation analysis and structural equation modeling unveiled diverse mechanisms of yield enhancement for HA, CMC, and AA treatments. HA enhanced yield by increasing organic matter and promoting soil aggregate formation, CMC improved soil water content and facilitated salt leaching due to its excellent water-holding properties, while AA increased yield by elevating soil organic matter and effective nitrogen content. Among the array of soil amendment materials scrutinized, HA treatment emerged as the most promising agent for enhancing soil conditions and is thus recommended as the preferred choice for treating local saline soils.

Effect of Sesbania and Triticale rotation on plant characteristics and soil quality in coastal saline-alkaline land: A two-year field experiment

Soil salinization and nutrient deficiency limit agricultural production in the Yellow River Delta region. This study investigates the green manure-forage grass rotation on soil quality and productivity. A two-year field experiment was conducted to investigate the effects of different varieties of Sesbania cannabina and ᵡTriticosecale Wittm rotations on soil properties, biological characteristics, and adaptability in coastal saline-alkali land. Four cropping rotation systems were set: Gaoyuan 2 – Lujing 2 (G2L2), Gaoyuan 2 – Lujing 5 (G2L5), Gaoyuan 1640 – Lujing 2 (G1640L2), and Gaoyuan 1640 – Lujing 5 (G1640L5). The G2L5 rotation demonstrated superior enhancement of soil quality. The soil organic matter increased by 35.8%, and the soil electric conductivity (CEC) increased by 20.2%. Compared with T. Wittm, S. cannabina had a significant positive effect on soil physical and chemical properties. S. cannabina L5 showed improved performance in mass density, fresh weight of stem, leaf and aboveground part, etc. After S. cannabina returned to the field, T. Wittm G2 had greater plant height, thousand-grain weight, and stem weight, and the yield reached 322 kg per 667 m2. In conclusion, G2L5 is the recommended planting model in saline-alkali soil. This research offers valuable insight for the efficient planting and sustainable development of coastal saline-alkali land.