Coastal Saline-alkali Soil Research Articles

Effect of three-year amendment measures on coastal saline-alkali soil conditions during the growing season

Seawater intrusion and fluctuations in the water table in coastal areas lead to seasonal variations in soil salinity and pH, which greatly limit the development of coastal protection forests. In a three-year field study, the impact of five soil amendment measures were evaluated on soil conditions in coastal areas. Amendments included biochar, biochar with arbuscular mycorrhizal fungi (AMF), straw with AMF, straw alone, and AMF alone, compared to a control (CK) with no additive. Results indicated that combinations of straw, biochar, and AMF reduced soil pH across various layers and seasons, with electrical conductivity mainly decreasing in spring. During the summer, at the 0-20 cm soil depth, microbial biomass carbon notably increased due to these mixtures. Additionally, AMF alone and biochar with AMF significantly improved enzyme activities in the 0-40 cm layer in spring, while in fall, AMF alone notably increased nutrient availability in the same layer. Linear regression analysis revealed a negative correlation between electrical conductivity, microbial biomass carbon, enzyme activity, and nutrient availability with pH. The biochar–AMF mixture emerged as the most effective soil amendment, suggesting that using it in conjunction with seasonal management could optimize soil health and promote silviculture in coastal regions.

Exogenous calcium-induced carbonate formation to increase carbon sequestration in coastal saline-alkali soil

Promoting soil carbon sequestration is a possible way to mitigate global warming. To investigate the effects of exogenous calcium on soil carbon sequestration during the application of organic matter to improve coastal saline-alkali soil. In this study, a 30-day incubation experiment was based on the application of corn straw biochar + chicken manure (BM) and rice straw + chicken manure (SM). Usages of exogenous calcium in each treatment under each organic matter combination as follow: CK (No exogenous calcium), CaSi1 (1.24 g CaSiO3, i.e. 4.28 g Ca kg−1 soil), CaSi2 (2.48 g CaSiO3, i.e. 8.56 g Ca kg−1 soil), CaOH1 (0.79 g Ca(OH)2, i.e. 4.28 g Ca kg−1 soil), CaOH2 (1.58 g Ca(OH)2, i.e. 8.56 g Ca kg−1 soil), CaSiOH (1.24 g CaSiO3 + 0.79 g Ca(OH)2, i.e. 8.56 g Ca kg−1 soil). Results showed that exogenous calcium significantly reduced CO2 emission. Organic matter addition promoted the loss of SOC, and exogenous did not significantly affect the mineralization of SOC albeit strongly increased SIC, making up for the loss of SOC, increasing soil total carbon and realizing soil carbon fixation. Soil carbon fixation was mainly realized by the reaction of exogenous calcium with CO2 generated by mineralization and converting it into calcium carbonate. pH and soil CO2 emission are the major controlling factors for soil inorganic carbon sequestration. Therefore, applying organic matter with exogenous calcium can realize soil carbon fixation by generation of calcium carbonate.

Responses of SOC, labile SOC fractions, and amino sugars to different organic amendments in a coastal saline-alkali soil

Organic amendment combined with mineral fertilizer is known as an effective management practice to improve soil carbon (C) sequestration in cropland. We evaluated the effects of three organic amendments combined with mineral fertilizer on soil organic carbon (SOC), labile SOC fractions, amino sugars, C mineralization, and C-cycle enzyme activities in a coastal saline-alkali soil. The three amendments, including straw (C/N of 75.5:1), straw biochar (C/N of 43:1), and soybean cake (C/N of 7.4:1), were continuously added into the soil at an equal C amount of 2250 kg C ha−1 for four years. Compared to mineral fertilizer alone, the contents of SOC in plots receiving straw, straw biochar, and soybean cake were increased by 7.6%, 17.3%, and 12.7%, respectively. The amendment of straw biochar mainly increased easily oxidizable carbon (EOC), particulate organic carbon (POC), and fungal-derived glucosamine, whereas straw and soybean cake mainly increased dissolved organic carbon (DOC), microbial biomass carbon (MBC), and bacteria-derived muramic acid. Meanwhile, the activities of C-cycle enzymes and C mineralization were higher in straw and soybean cake treatments than in straw biochar treatment. EOC and POC, but not DOC and MBC, were strongly positively correlated with fungal-derived glucosamine and SOC, suggesting that EOC or POC could be used as appropriate indicators to predict SOC sequestration potential. In addition, the C/N ratio of organic material did not affect SOC and its components. In conclusion, straw biochar promotes the maximum accumulation of SOC through increasing EOC, POC, and fungal necromass.

Effects of coastal saline-alkali soil on rhizosphere microbial community and crop yield of cotton at different growth stages.

Soil salinization is a global constraint that significantly hampers agricultural production, with cotton being an important cash crop that is not immune to its detrimental effects. The rhizosphere microbiome plays a critical role in plant health and growth, which assists plants in resisting adverse abiotic stresses including soil salinization. This study explores the impact of soil salinization on cotton, including its effects on growth, yield, soil physical and chemical properties, as well as soil bacterial community structures. The results of β-diversity analysis showed that there were significant differences in bacterial communities in saline-alkali soil at different growth stages of cotton. Besides, the more severity of soil salinization, the more abundance of Proteobacteria, Bacteroidota enriched in rhizosphere bacterial composition where the abundance of Acidobacteriota exhibited the opposite trend. And the co-occurrence network analysis showed that soil salinization affected the complexity of soil bacterial co-occurrence network. These findings provide valuable insights into the mechanisms by which soil salinization affects soil microorganisms in cotton rhizosphere soil and offer guidance for improving soil salinization using beneficial microorganisms.

Application of carboxymethyl cellulose sodium (CMC[sbnd]Na) in maize–wheat cropping system (MWCS) in coastal saline-alkali soil

Sodium carboxymethyl cellulose (CMCNa) application has been a promising approach to improve soil quality. The purpose of this study was to explore the effects of CMC-Na on soil infiltration, evaporation, water-salt distribution, crop growth, water use efficiency and net profit (Net) in a coastal saline-alkali soil maize–wheat cropping system (MWCS). Five CMC-Na application amounts (0, 0.1, 0.2, 0.4 and 0.6 g kg−1) were designed for the soil column experiment indoor, and five CMC-Na application amounts were used in 2019–2020 field experiment (CK: 0, C10: 10 kg ha−1, C20: 10 kg ha−1, C30: 10 kg ha−1 and C50: 10 kg ha−1), No treatment will be applied in 2021. The results showed that (1) CMC-Na treatment reduced soil cumulative infiltration, infiltration rate, daily evaporation, and cumulative evaporation. (2) After the application of CMCNa, the average soil water storage (SWS) in the 0–60 cm soil layer increased, and soil salinity (SSC) decreased in most treatments. (3) In the 2019–2020, the maize aboveground biomass (B), yield (Y) and water use efficiency (WUE) were the highest under the C20 and C30 treatments, which were 15.24 and 15.32 t ha−1, 5.67 and 5.49 t ha−1 and 1.74 and 1.52 kg ha−1 mm−1, respectively, and the wheat under C30 treatment is the highest, which were 10.98 t ha−1, 5.27 t ha−1 and 1.78 kg ha−1 mm−1. (4) A dose of 25.5 kg ha−1 and 38.9 kg ha−1 was recommended as the most optimal CMC-Na application for maize and wheat in coastal saline alkali soil, respectively.

Accumulation and migration of microplastics and its influencing factors in coastal saline-alkali soils amended with sewage sludge

Coastal saline-alkali soil can be transformed to agricultural soil with sewage sludge amendment. However, sewage sludge contains a large number of microplastics (MPs), and the fate of MPs in sludge-treated saline-alkali soil needs to be studied. Therefore, we investigated the accumulation and migration of MPs, and their influencing factors in saline-alkali soil after one-time sewage sludge application (0, 25, 50, 100 and 200 t ha−1 SSA). The results indicated that sewage sludge input contributed to MP accumulation in soil, and the MP abundance in 20–40 cm soil was significantly lower than that in 0–20 cm soil. Fragments and fibers were the most abundant MPs in soil, and the proportions of fragments and 50–200 µm MPs in 20–40 cm soil were lower than those in 0–20 cm soil, while the < 50 µm MP proportion was higher than that in 0–20 cm soil. Correlation analysis showed that MP accumulation rate (0–40 cm) and migration rate (20–40 cm) were negatively correlated with soil organic matter (SOM) content and SSA, but positively correlated with soil pH. Stepwise regression analysis further showed that SOM and SSA were the main factors affecting MP accumulation rate, which explained 47.7% and 46% of its variation, respectively, while pH was the crucial factor affecting the migration rate of MPs, followed by EC and SSA. In conclusion, SSA caused MP accumulation in saline-alkali soil, and SSA primarily affected the MP abundance, while soil OM, pH and EC directly affected MP migration in soil.

Sub‐soil plastic film mulch promotes the growth and yield improvement of winter wheat in coastal saline–alkali soil

AbstractCrop yields are seriously threatened in saline–alkali areas with shallow groundwater levels and high evaporation. Mulching can effectively alleviate salt stress on crops in drylands, but there is limited research on winter wheat (Triticum aestivum L.) mulching in coastal saline–alkali areas. To investigate the effect of plastic film mulching on the growth and yield of wheat in coastal saline–alkali soil, three field management measures were designed: bare ground (CK), plastic film mulch (PM), and sub‐soil plastic film mulch (PMF). Compared with CK, PM and PMF significantly increased wheat grain yield by 128.2%–313.2% and 187.8%–537.0%, respectively, over the two study stages. The movement of salt to the surface is inhibited after mulching; as a result, PMF and PM significantly decreased the electric conductivity in shallow soil (0–20 cm) by 31.1% and 23.8%, on average, compared to CK, resulting in a significant increase in dry matter accumulation (DM) for winter wheat throughout the growing season. Moreover, PMF increased the overall DM by increasing the dry matter accumulation per plant (DMP), while PM achieved a similar effect to PMF by increasing the number of tillers. Compared with PM, PMF had a better inhibitory effect on shallow soil salinity, significantly increasing the effective number of spikes, effective tillering rate, DMP, and spike weight at harvest; promoting vegetative and reproductive growth of wheat fields; and ultimately increasing yield. PMF can be used to improve winter wheat production in coastal saline–alkali soils.

Effects of Phosphate Application Rate on Grain Yield and Nutrition Use of Summer Maize under the Coastal Saline-Alkali Land

Saline-alkali soil is a major threat to global food security. Phosphorus (P) fertilizer is essential for crop growth and yield production. Nevertheless, the optimal phosphate fertilizer application rates for summer maize under coastal saline–alkali soil are still unclear. A field experiment with five phosphate application rates (0, 45, 90, 135, and 180 kg ha−1, referred to as T1, T2, T3, T4, and T5, respectively) was conducted during the 2018–2020 summer maize seasons study the effects of phosphate rates on the grain yield, biomass, and nitrogen (N), P and potassium (K) accumulation, and N, P, and K physiological efficiency (denoted as NPE, PPE and KPE, respectively). Results showed that P application notably improved maize grain and biomass yield, the total uptake of N, P, K, and NPE and KPE across three seasons. As the P addition increased to 135 kg ha−1, the grain yield achieved a maximum of 7168.4 kg ha−1, with an average NPE of 2.15 kg kg−1, PPE of 0.19 kg kg−1, and KPE of 1.49 kg kg−1. However, PPE continuously decreased with the input of phosphate. P application rates exceeding 135 kg ha−1 were not considered effective due to a decline in grain yield, nutrient uptake, and NPE. Furthermore, the effect of the planting season was significant on the total uptake of N and K, and the use efficiency of N, P, and K. TOPSIS revealed that a phosphate application rate of 90–135 kg ka−1 was the optimal pattern for maize production. These results may give a theoretical basis for the phosphate management of maize production in saline–alkali soil.

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.

Application of Desulphurized Gypsum with Straw to Improve Physicochemical Properties of Saline-alkali Land in Yellow River Delta

In order to explore the effect of combining straw and desulphurized gypsum on improving coastal saline-alkali soil, taking the alkaline saline soil in the Yellow River Delta as the research object, six treatments including the control (CK), desulphurized gypsum (DG), medium straw amount (MS), desulphurized gypsum+low straw amount (DGLS), desulphurized gypsum+medium straw amount (DGMS), and desulphurized gypsum+high straw amount (DGHS) were set up through a field location experiment. Combined with the aggregate classification method, the changes in bulk density, total porosity, pH, soluble salt content, microbial biomass carbon, dissolved organic carbon, new carbon, and aggregate organic carbon of coastal saline alkali soil under different treatments were compared. The results showed that the MS and DGHS treatments significantly reduced soil bulk density and increased soil total porosity, water content, and average weight diameter. The pH and exchange sodium percentage decreased significantly under all treatments, and there was no significant difference. DG treatment significantly reduced the soil sodium adsorption ratio. Compared with that in the MS treatment, the soil sodium adsorption ratio of DGLS, DGMS, and DGHS showed a further decreasing trend, with a decrease range of 57%-66%. Compared with MS, soil soluble Na+ decreased by 27.92%, 32.23%, and 20.15% under the DGLS, DGMS, and DGHS treatments, whereas the soil soluble Ca2+ and SO42- contents increased significantly. Compared with that in CK, all treatments could significantly reduce Cl- content, and there was no significant difference among all treatments. Compared with that in MS, microbial biomass carbon and dissolved organic carbon were significantly increased by 113% and 147% by DGMS and 22.81% and 28.24% by DGHS, respectively. The new carbon formation of DGLS, DGMS, and DGHS was 67%, 114%, and 175% higher than that of MS, respectively. The average size proportion of fine aggregates treated by DGLS, DGMS, and DGHS was 29.12% higher than that treated by MS. Straw returning and application of desulfurized gypsum increased the organic carbon content of coarse aggregates and fine aggregates in salinized soil. The average value of new carbon formation in coarse aggregates and fine aggregates treated by DGMS and DGHS was 233% and 142% higher than that treated by MS, respectively. Desulphurized gypsum applied to soil did not lead to soil heavy metal pollution, and the soil heavy metal content of different treatments was lower than the secondary standard of the soil environmental quality standard. These results can provide scientific basis for the improvement and utilization of coastal saline-alkali soil and the comprehensive utilization of industrial and agricultural wastes in the Yellow River Delta.

Soil habitat condition shapes Tamarix chinensis community diversity in the coastal saline-alkali soils.

Unfavorable coastal saline-alkali soil habitats degrade plant community diversity and reduce terrestrial ecological functions. Previous studies have been conducted on the mechanisms by which certain saline-alkali soil properties determine plant community diversity, however, how those properties synergistically affect plant community diversity remains unclear. Here, 36 plots of typical Tamarix chinensis communities were investigated for a range of parameters at three different distances (10, 20, and 40 km) from the coastline in the Yellow River Delta between 2020 and 2022, and corresponding soil samples were taken and analyzed. Our results suggest that although T. chinensis density, ground diameter, and canopy coverage significantly increased (P<0.05) with increasing distance from the coast, the communities with the most plant species were found at 10 to 20 km distance from the coastline, indicating the effects of soil habitat on T. chinensis community diversity. Simpson dominance (species dominance), Margalef (species richness), and Pielou indices (species evenness) differed significantly among the three distances (P<0.05) and were significantly correlated with soil sand content, mean soil moisture, and electrical conductivity (P<0.05), indicating that soil texture, water, and salinity were the main factors governing T. chinensis community diversity. Principal component analysis (PCA) was performed to construct an integrated soil habitat index (SHI) representing the synthesis of the soil texture-water-salinity condition. The estimated SHI quantified a 64.2% variation in the synthetic soil texture-water-salinity condition and was significantly higher at the 10 km distance than at the 40 and 20 km distances. The SHI linearly predicted T. chinensis community diversity (R2 = 0.12-0.17, P<0.05), suggesting that greater SHI (coarser soil texture, wetter soil moisture regime, and higher soil salinity) was found closer to the coast and coincided with higher species dominance and evenness and lower species richness in the T. chinensis community. These findings on the relationship between T. chinensis communities and soil habitat conditions will be valuable in planning the restoration and protection of the ecological functions of T. chinensis shrubs in the Yellow River Delta.

Effects of Different Exogenous Organic Materials on Improving Soil Fertility in Coastal Saline-Alkali Soil

The coastal saline-alkali soil in eastern China is an important reserve arable land resource. Adding exogenous organic material is an effective way to improve soil fertility and promote the conversion of saline-alkali soil to agricultural soil. In this study, a field plot experiment was used to investigate the influences of different organic materials (vinegar residue, VR; sewage sludge, SS; vermicompost, VC) on the reduction in salinity-alkalinity barrier factors, the accumulation of soil organic carbon (SOC), and the improvement in soil fertility in saline-alkali soil. The results indicated that applying different types of exogenous organic materials reduced soil electrical conductivity (EC) and pH, promoted SOC accumulation, and increased the barley yield. With the same application rate, VR application was more beneficial in reducing soil EC and pH, accumulating SOC, and increasing barley yield compared to SS and VC applications. In particular, the barley yield with VR application was higher than that with SS and VC applications by 18.4% and 26.6% on average, respectively, during the two-year experiment. Correlation and path analysis revealed that the barley yield was significantly negatively correlated with soil barrier factors (EC and pH), but EC in SS and VC-treated soils had an indirect negative effect on barley yield, while EC in VR-treated soil had a direct negative effect (−2.24). In addition, the direct (−4.46) and indirect (5.39) contributions of SOC to barley yield were higher with VR than those with SS and VC, while the direct contribution of soil aggregate to barley yield was lower with VR than that with SS and VC. Therefore, compared with SS and VC applications, VR application led to a fast reduction in soil barrier factors and the rapid accumulation of SOC, which were more beneficial for increasing barley yields in saline-alkali soil.

Salinization of coastal saline-alkali soil might enhance H2S release by affecting H2S-related bacterial communities

Bacterial metabolism can result in the production and release of hydrogen sulfide (H2S), a reductive gas, in soils. Hydrogen sulfide-releasing bacteria (HSRB) assimilate organic sulfur or dissimilate sulfate to generate and release H2S, whereas H2S-oxidizing bacteria (HSOB) oxidize H2S generated by themselves or other bacteria to soluble sulfate resulting in sulfur retention in soil. However, the effects environmental factors such as electrical conductivity on both these bacterial groups and H2S release remain unclear; some key processes such as H2S oxidation also remain underexplored. In this study, we found that high electrical conductivity in coastal saline-alkali soil affects these bacterial communities, especially HSRB, potentially enhancing H2S release. The “sink” of H2S gas, represented by sulfidic sulfur (concentration, 0.2–3.4 nmol/g) in coastal saline-alkali and inland soils, was determined using the methylene blue method, and found to be positively correlated with soil electrical conductivity, suggesting that more H2S gas potentially volatilized from salinized soil. We then revealed that the proportion of HSRB clones was correlated positively and significantly with the electrical conductivity and sulfidic sulfur of soil, but not with the pH or sulfur source. Further, 16S rRNA gene sequence comparison indicated significantly reduced richness and diversity of bacterial communities and considerably altered the composition of dominant bacterial populations in coastal saline-alkali soil. The phyla Proteobacteria, Bacteroidetes, and Gemmatimonadetes accounted for 38 %, 30.1 %, and 11.1 % and for 28 %, 12.9 %, and 2.5 % of the bacterial populations in coastal saline-alkali and inland soil, respectively. PICRUSt analysis showed that the richness of genes encoding the key H2S oxidation enzymes, sulfide:quinone reductase and sulfate hydrolase, was decreased significantly and negatively correlated with the detected sulfidic sulfur. These enzymes are usually expressed by HSOB in coastal saline-alkali soil, implying a low sulfide oxidation capacity. These results indicate that the number of HSRB is increased whereas the ability of H2S oxidation is decreased in coastal saline-alkali soil, which might lead to enhanced H2S release. Overall, this study provides new insights for understanding the sulfur biological cycle in saline-alkali soils.

Responses of Phragmites australis to Nitrogen Addition along Salinity Gradients in Coastal Saline–Alkali Soil

Soil salinization and nitrogen (N) enrichment in saline–alkali soils resulting from human activities cause potential environmental pressure on Phragmites australis. However, the response of P. australis to N addition under different salt conditions remains unknown. This study examined the changes in soil properties and growth indices as well as their relationship to N addition through an in situ field experiment using three soil salinity levels with P. australis in the Yellow River Delta. The study showed that soil salinity levels significantly affected the effects of N addition on soil pH and water contents. N addition increased the soil NO3– contents and decreased soil available phosphorus (Avail. P) contents; however, soil salinity levels did not impact the effects of N addition on soil NO3− and Avail. P contents. N addition decreased the biomass of P. australis, since the decrease in the competitiveness for N sources changed the vegetation diversity. The results suggest that the biomass, plant height, and leaf soil plant analysis development (SPAD) values of P. australis increased with increasing soil Avail. P contents rather than soil NO3– contents. Therefore, we suggest the important role of Avail. P addition in N enrichment conditions in saline–alkali wasteland and estuarine wetland ecosystems.

Effects of different growth patterns of Tamarix chinensis on saline-alkali soil: implications for coastal restoration and management.

To better understand the wetland restoration, the physicochemical property and microbial community in rhizosphere and bulk soil of the living and death Tamarix chinensis covered soil zones were studied. There were differences between growth conditions in the levels of soil pH, salinity, SOM, and nutrient. The living status of T. chinensis exhibited higher capacity of decreasing saline-alkali soil than the death condition of plants, and the living T. chinensis showed higher uptake of N, P, and K as compared with the death samples. Proteobacteria, Bacteroidota, and Chloroflexi were the predominant bacterial communities as revealed via high-throughput sequencing. It is great potential for using halophytes such as T. chinensis to ecological restore the coastal saline-alkali soil. This study could contribute to a better understanding of halophyte growth during the coastal phytoremediation process, and guide theoretically for management of T. chinensis population.

Genome-wide identification of calcineurin B-like protein-interacting protein kinase gene family reveals members participating in abiotic stress in the ornamental woody plant Lagerstroemia indica.

Calcineurin B-like protein-interacting protein kinases (CIPKs) play important roles in plant responses to stress. However, their function in the ornamental woody plant Lagerstroemia indica is remains unclear. In this study, the LiCIPK gene family was analyzed at the whole genome level. A total of 37 LiCIPKs, distributed across 17 chromosomes, were identified. Conserved motif analysis indicated that all LiCIPKs possess a protein kinase motif (S_TKc) and C-terminal regulatory motif (NAF), while seven LiCIPKs lack a protein phosphatase interaction (PPI) motif. 3D structure analysis further revealed that the N-terminal and C-terminal 3D-structure of 27 members are situated near to each other, while 4 members have a looser structure, and 6 members lack intact structures. The intra- and interspecies collinearity analysis, synonymous substitution rate (Ks) peaks of duplicated LiCIPKs, revealed that ∼80% of LiCIPKs were retained by the two whole genome duplication (WGD) events that occurred approximately 56.12–61.16 million year ago (MYA) and 16.24–26.34 MYA ago. The promoter of each LiCIPK contains a number of auxin, abscisic acid, gibberellic acid, salicylic acid, and drought, anaerobic, defense, stress, and wound responsive cis-elements. Of the 21 members that were successfully amplified by qPCR, 18 LiCIPKs exhibited different expression patterns under NaCl, mannitol, PEG8000, and ABA treatments. Given that LiCIPK30, the AtSOS2 ortholog, responded to all four types of stress it was selected for functional verification. LiCIPK30 complements the atsos2 phenotype in vivo. 35S:LiCIPK-overexpressing lines exhibit increased leaf area increment, chlorophyll a and b content, reactive oxygen species scavenging enzyme activity, and expression of ABF3 and RD22, while the degree of membrane lipid oxidation decreases under NaCl treatment compared to WT. The evolutionary history, and potential mechanism by which LiCIPK30 may regulate plant tolerance to salt stress were also discussed. In summary, we identified LiCIPK members involved in abiotic stress and found that LiCIPK30 transgenic Arabidopsis exhibits more salt and osmotic stress tolerance than WT. This research provides a theoretical foundation for further investigation into the function of LiCIPKs, and for mining gene resources to facilitate the cultivation and breeding of new L. indica varieties in coastal saline-alkali soil.

Effects of cotton stubble return and subsoiling on dry matter accumulation, nutrient uptake, and yield of cotton in coastal saline-alkali soil

<p id="C3">To study the effects of cotton straw returning and deep loosening on cotton yield, salt content in 0-40 cm soil layer, dry matter accumulation dynamics, nitrogen (N), phosphorus (P), and potassium (K) accumulation, and distribution characteristics, four treatments including conventional tillage (CT), subsoiling tillage (ST), cotton stubble return (SR), and cotton stubble return + subsoiling tillage (SRT) were conducted using Lumianyan 36 as experimental material. The results showed that cotton stubble return increased cotton yield across two years. Lint yield of SR was 33.9% higher than CT, and SRT 32.1% higher than SR. Subsoiling increased cotton yield in 2017 and had no effect on it in 2018. Cotton stubble return reduced the salt content of 0-40 cm soil layer. The salt content of SR was 22.4% lower than that of CT, and the soil salt content of SRT was 20.7% lower than that of ST at the late growth stage in cotton. However, the effect of subsoiling on the salt content of 20-40 cm soil layer was inconsistent during the two-year experiment. The soil salt content of ST was 16.5% lower than of CT at late growth stage in 2017, but subsoiling had no effect on soil salt content in 2018. The accumulation dynamic of dry matter and N, P, K in cotton were consistent with the Logistic growth curve. Cotton stubble return increased maximal accumulation of dry matter and N, P, K in two years. The maximum accumulation of dry matter, N, P, and K in SR was 35.5%, 38.3%, 53.4%, and 55.0% higher than that in CT, and the accumulation of SRT was 27.0%, 30.7%, 21.2%, and 42.4% higher than that in ST. Compared with CT, the dry matter, N, P, and K accumulation of ST increased by 17.8%, 22.2%, 51.3%, and 40.6% in 2017, respectively, but had no effect in 2018. The dynamic of dry matter and nutrient accumulation were mainly affected by the maximum accumulation rate and rapid accumulation duration. Stubble return increased the amount and proportion of dry matter and N, P, K allocated to reproductive organs of cotton in the two-year experiment. Compared with CT, ST increased the allocation amount of dry matter and N, P, K to reproductive organs in 2017, but had no effect in 2018. In summary, the results revealed that cotton stubble return (SR) or cotton stubble return + subsoiling tillage (SRT) could be recommended tillage measures for soil improvement and high cotton yield in coastal saline-alkali cotton area.

Effect of freezing temperature and water content on pore structure characteristics of coastal saline-alkali soil under frost heave

Effect of freezing temperature and water content on pore structure characteristics of coastal saline-alkali soil under frost heave

Revitalizing coastal saline-alkali soil with biochar application for improved crop growth

The wheat straw biochar has well pronounced effects on the coastal saline-alkali soil remediation/health. The soil water content in saline-alkali soil increased by 12.4–16.6% (2014), 18.1–63.4% (2015), 23.9–42.6% (2016) with 0, 20, 40, and 60 t ha−1 application of wheat straw biochar. The different chemical properties like pH, CEC (cation exchange capacity) and SOM (soil organic matter) ranged between 0.2 and 3.1, 6.7–82.0% and 12.6–139.6%, respectively with biochar application during three years of field experiment. The TSS (total soluble salt) of different biochar treatments in the soil decreased by 15.9–23.7% (2014), 28.6–54.6% (2015), 11.7–42.2% (2016) compared with control. The exchangeable/soluble cations like Calcium (Ca), Magnesium (Mg), chlorine (Cl) and Sodium (Na) concentration showed the similar trend as that of TSS. The soil soluble potassium (K) concentration significantly increased by 82.5–233.1% (2014), 65.3–228.2% (2015), 19.2–233.8% (2016) compared with control, which mainly originated from biochar. The wheat straw biochar application improves the coastal saline-alkali soil health and environment, which promoted the crop growth. The biochar amendment improved the soil properties with decrease in the salt concentration that showed biochar potential to improve/remediate the saline alkali soil.

Effects of Organic and Inorganic Amendments on Aggregate Stability and Microbial Communities of Coastal Saline–Alkali Soil in the Yellow River Delta

Effects of Organic and Inorganic Amendments on Aggregate Stability and Microbial Communities of Coastal Saline–Alkali Soil in the Yellow River Delta