Reduce Soil Salinity Research Articles

Multi-Level Comprehensive Assessment of Constructed Wetland Ecosystem Health: A Case Study of Cuihu Wetland in Beijing, China

Wetlands are one of the world’s three major ecosystems. They not only maintain regional ecological balance but also provide an important guarantee for human survival. Wetland ecosystem health assessment serves as the foundation for wetland protection, management, and restoration. In this study, the method for wetland ecosystem health assessment proposed by the United States Environmental Protection Agency (US EPA) was selected and improved to systematically evaluate the health status of the Cuihu wetlands’ ecosystem at three levels. The results revealed that the Cuihu wetlands’ landscape development intensity index was 1.55, the total landscape pattern value was 10 points, and the total score for rapid evaluation was 0.79. Levels I and II indicated that the Cuihu wetlands’ ecosystem was in a good near-natural state. Additionally, level III revealed that ecosystem health is higher in area B than in area A. The Cuihu wetlands were characterized by low species diversity and low distribution of benthic animals and aquatic plants. The comprehensive evaluation results revealed that the Cuihu wetlands’ ecosystem is in a good health. In the future, the health status of the wetland ecosystem should be monitored regularly, the cultivation and propagation of aquatic plants should be strengthened, and effective methods to improve water quality and reduce soil salinity should be used to achieve the best health status of the Cuihu wetlands.

Using liquefied biomass hydrogel to mitigate salinity in salt-affected soils

Salinity affects over 33% of irrigated farmland globally. Developing a low-cost, safe, and effective material as a soil salinity mitigation option would be of significant importance. This study proposed to synthesize a hydrogel using liquefied biomass from sugarcane bagasse, polyvinyl alcohol, and sodium tetraborate decahydrate. The effectiveness of the produced hydrogel in mitigating soil salinity was evaluated based on an incubation experiment at two salinity levels (5 and 10 dS m-1). The experiment was conducted by mixing liquefied hydrogel with soil at four application rates (0, 1, 2, and 3% w/w) with three replications. Porewater and soil samples were tested for pH and electrical conductivity (EC). Soil samples were also analyzed for selected cations and anions. The results demonstrated that hydrogel significantly reduced porewater EC at both 5 and 10 dS m-1 salt solutions. In addition, hydrogel reduced Cl-, P, Ca2+, and Al3+ concentrations in soil samples with maximum reductions observed from 3% hydrogel treatment. However, pH of porewater showed a consistent increase with hydrogel application. The application of hydrogel also increased NH4–N at high salt level. Overall, hydrogel has shown promising results in reducing soil salinity and could potentially be used as a soil amendment for saline soils.

Effect of Different Types of Mulches on Yield of Pumpkin in Salt Affected Soil

For reducing soil salinity and obtaining a sustainable yield, a low-cost and farmer-friendly method is required for pumpkin, a well-liked vegetable. Accordingly, a field experiment was carried out in Salinity Management and Research Center, Soil Resource Development Institute, Batiaghata, Khulna during Kharif-1 season of 2021 to investigate the effect of different types of mulches on soil salinity and yield of pumpkin. The experiment includes three treatments viz. no mulch (control), straw mulch and mulching paper. The experiment was carried out in Randomized Complete Block Design with four replications. Soil salinity was recorded at 30 days intervals. All mulching materials effectively reduced the salt accumulation in the root zone. After three months of seed sowing, the highest soil salinity (11.32 dS/m) and lowest soil salinity (6.24 dS/m) were found at no mulch (control) and mulching paper treatment respectively in the month of May. Mulching treatments markedly increased the growth and yield attributes of pumpkins. The highest value of three growth parameters i.e., fruit length (26.92 cm), fruit diameter (94.09 cm) and fruit size (2037 cm2) was found on mulching paper as compared to control. Again, the highest flesh thickness (3.94 cm), fruit weight (4.73 kg) and yield (31.18 t/ha) were recorded at mulching paper treatment whereas the lowest yield (16.68 t/ha) was found at no mulch (control). The results revealed that the use of mulching paper decreased salinity and also increased the yield of pumpkin in saline soil. These findings suggest that the application of mulching paper not only reduces soil salinity but also increases the yield of pumpkins.

Transcriptome analysis reveals molecular mechanisms underlying salt tolerance in halophyte Sesuvium portulacastrum.

Soil salinity is an important environmental problem that seriously affects plant growth and crop productivity. Phytoremediation is a cost-effective solution for reducing soil salinity and potentially converting the soils for crop production. Sesuvium portulacastrum is a typical halophyte which can grow at high salt concentrations. In order to explore the salt tolerance mechanism of S. portulacastrum, rooted cuttings were grown in a hydroponic culture containing ½ Hoagland solution with or without addition of 400 mM Na for 21 days. Root and leaf samples were taken 1 h and 21 days after Na treatment, and RNA-Seq was used to analyze transcript differences in roots and leaves of the Na-treated and control plants. A large number of differentially expressed genes (DEGs) were identified in the roots and leaves of plants grown under salt stress. Several key pathways related to salt tolerance were identified through KEGG analysis. Combined with physiological data and expression analysis, it appeared that cyclic nucleotide gated channels (CNGCs) were implicated in Na uptake and Na+/H+ exchangers (NHXs) were responsible for the extrusion and sequestration of Na, which facilitated a balance between Na+ and K+ in S. portulacastrum under salt stress. Soluble sugar and proline were identified as important osmoprotectant in salt-stressed S. portulacastrum plants. Glutathione metabolism played an important role in scavenging reactive oxygen species. Results from this study show that S. portulacastrum as a halophytic species possesses a suite of mechanisms for accumulating and tolerating a high level of Na; thus, it could be a valuable plant species used for phytoremediation of saline soils.

Effects of planting of two common crops, Allium fistulosum and Brassica napus, on soil properties and microbial communities of ginseng cultivation in northeast China

BackgroundLong-term cultivation of ginseng can cause severe crop disorders and soil sickness. Crop rotation is an effective agricultural management measure to improve soil sustainability and decrease pathogens. However, the suitable ginseng rotation system and the changes in soil microbial community and soil characteristics under the rotation system need to be further explored.MethodsTo explore suitable ginseng crop rotation systems and improve soil utilization, Allium fistulosum and Brassica napus were planted on ginseng cultivation soil for one year. The effects of the two crops on the chemical properties and enzyme activities of the ginseng cultivation soil were evaluated by chemical analysis. In addition, amplicon sequencing targeting 16 s rDNA genes of bacteria and ITS of fungi has been used to characterize the functional and compositional diversity of microbial communities.ResultsThe results elucidated that the levels of available phosphorus (AP) and available potassium (AK) in the soil increased significantly after one year of cultivation for both crops and Allium fistulosum cultivation may also have reduced soil salinity. In addition, the effects of the two crops on the activities of key soil enzymes were different. Catalase (CAT), urease (URE), and acid phosphatase (A-PHO) activities were significantly reduced and sucrase (SUC), and laccase (LAC) activities were significantly increased after Allium fistulosum planting. While A-PHO activity was significantly increased and LAC activity was significantly decreased after Brassica napus planting. Allium fistulosum significantly reduced the abundance of soil fungal communities. The cultivation of Allium fistulosum and Brassica napus significantly altered the composition of soil bacterial and fungal communities, where changes in the abundance of dominant microorganisms, such as Ascomycota, and Mortierellomycota, etc., were closely related to soil chemistry and enzyme activity. Moreover, both significantly reduced the abundance of the pathogenic fungus Ilyonectria.ConclusionsOur study clarified the effects of Allium fistulosum and Brassica napus on the microbial community and physicochemical properties of ginseng cultivated soil and provides a basis for the sustainable application of ginseng cultivation soil and the development of ginseng crop rotation systems.

Long-distance facilitation of coastal ecosystem structure and resilience

Biotic interactions that hierarchically organize ecosystems by driving ecological and evolutionary processes across spatial scales are ubiquitous in our biosphere. Biotic interactions have been extensively studied at local and global scales, but how long-distance, cross-ecosystem interactions at intermediate landscape scales influence the structure, function, and resilience of ecological systems remains poorly understood. We used remote sensing, modeling, and field data to test the hypothesis that the long-distance impact of an invasive species dramatically affects one of the largest tidal flat ecosystems in East Asia. We found that the invasion of exotic cordgrass Spartina alterniflora can produce long-distance effects on native species up to 10 km away, driving decadal coastal ecosystem transitions. The invasive cordgrass at low elevations facilitated the expansion of the native reed Phragmites australis at high elevations, leading to the massive loss and reduced resilience of the iconic Suaeda salsa "Red Beach" marshes at intermediate elevations, largely as a consequence of reduced soil salinity across the landscape. Our results illustrate the complex role that long-distance interactions can play in shaping landscape structure and ecosystem resilience and in bridging the gap between local and global biotic interactions.

Magnetized Water and Proline to Boost the Growth, Productivity and Fruit Quality of ‘Taifi’ Pomegranate Subjected to Deficit Irrigation in Saline Clay Soils of Semi-Arid Egypt

Water scarcity is becoming a global problem. The shift from traditional irrigation systems to deficit irrigation increased soil salinity, particularly in clay soils. The use of magnetized water (MW) and biostimulants can induce plant resistance to drought and salinity stress. To assess the role of MW and proline (P) on ‘Taifi’ pomegranate shrubs’ growth, productivity, and fruit quality under such conditions, a split-plots experiment was conducted for two seasons using three irrigation levels (100%, 75%, and 50%), based on the crop water requirements (CWR), and four treatments including foliar spray of tap water (control) and P, irrigation with MW, and MW + P. The most pronounced effect was referred to MW + P at 75% CWR that improved shrubs’ chlorophyll content and nutritional status, reduced endogenous proline content, and enhanced vegetative growth with minimum consumptive water use (CWU), optimum water use efficiency (WUE), maximum water productivity (WP), utmost yield and average fruit weight, lowest percentage of fruit cracking, and fairly good total soluble solids (TSS), vitamin C and anthocyanin contents. Overall, MW + P at 75% CWR improved the resistance mechanism of pomegranate shrubs in saline clay soils, plus improving the growers’ net profit. MW generally reduced soil salinity, expressed as reduced pH, EC, Na+, and Ca2+ values.

Application of a vertical ‘electric sieve’ to mitigate and prevent salinization in coastal soil

AbstractThis study explored the applications of a vertical electrokinetic system (V‐EK), which consists of multilayer electrodes positioned in shallow soil to form an ‘electric sieve’ to mitigate and prevent soil salinization caused by salts rising from saline groundwater in coastal areas. The experiments were conducted in column reactors in the laboratory. Compared to the control column, the level of ions in the surface soil was significantly reduced after the V‐EK treatment, particularly for the column with voltages at 10 V and 20 V. At a voltage of 20 V, Na+ was detected at a range of 0.06–0.08 mg g−1 in the surface soil; this is a >99% reduction compared to the controls. Similar efficacy was observed for Cl− in the V‐EK column. The concentrations of Cl− were detected with a range of 0.01–0.02 mg g−1 and 0.02–0.06 mg g−1 at the surface soil with a voltage of 20 V and 10 V, respectively, compared to the Cl− concentrations at 0.84–2.70 mg g−1 in the control. After the application of the vertical ‘electric sieve’, the total salt content of surface soil could be controlled at a low value (<0.25‰) at voltages of 10 V and 20 V, compared to that in the control column (4.86‰). Finally, rising of salts from the artificial saline groundwater was effectively mitigated under voltages of 10 V and 20 V. Results from this work have demonstrated that the ‘electric sieve’ can effectively mitigate and prevent salts from rising in shallow groundwater to surface soil and reduce soil salinity.

Desalinization effect of simulated cut‐soiler‐based residue filled preferential shallow subsurface drainage: Improvement of physiology and yield of rain‐fed pearl millet in saline semiarid regions

AbstractSoil salinity is a major soil degradation problem that limits agricultural production. The cut‐soiler constructed preferential shallow subsurface drainage (PSSD) method is a promising salinity management technology for small‐scale application and adoption in drylands. This study assessed the effectiveness of rice residue‐filled PSSD in managing soil salinity and its effect on the physiology and yield of pearl millet. The cut‐soiler simulated drains were constructed manually in semi‐controlled lysimeter. A double replicated, split–spilt plot experiment, comprising with and without cut‐soiler drainage (main‐plot), two soil types (sub‐plot) and three irrigation water salinity (4, 8, 12 dS m−1) (sub‐sub plot) were conducted during 2019–2020. The cut‐soiler PSSD reduced ~60% soil salinity after 2 years. The PSSD reduced soil salinity by 23.28 and 41.46% in April 2019 and April 2020 (before pearl millet sowing). This reduction was 32.24 and 46.23% in October 2019 and 2020 (at harvest). Cut‐soiler drainage (PSSD) areas recorded lower soil moisture (%) indicated greater outflow of water and salinity. The salinity Inhibition efficiency increased upto 2 years of construction and then decline. The pearl millet grain and biological yields were improved by 23.54 and 12.64%, respectively and a positive effect on plant water relations and physiology was observed. The cut‐soiler PSSD was found to enhance salt removal and reduce salt accumulation under saline water irrigation. These drains can be constructed in a single farm operation at individual farm levels. Therefore, it could be a potential alternative for soil salinity management in semi arid regions irrigated with saline groundwater.

Changes in physical and chemical properties of saline soil amended with municipal solid waste compost and chemical fertilizers in a mustard–pearl millet cropping system

AbstractSoil salinity is a severe threat in arid and semiarid agro‐ecosystem of India, and it is directly influenced by soil physical properties. Therefore, understanding the dynamic nature of salinity is the key to implementing suitable management options for re‐builing the fertility of saline soils. In this context, we conducted field experiments in saline soil, comprising five treatments (1‐5 following) and a control (C). These are: C) no amendments and chemical fertilizer; T1) recommended dose nitrogen, phosphorus, and potassium (N‐P‐K) fertilizers @60:30:30 kg ha−1; T2) 100% recommended dose of chemical fertilizers (RDF).; T3) rice straw compost (RSC) @14 Mg ha−1; T4) gypsum enriched compost (GEC) @14 Mg ha−1; and T5) municipal solid waste compost @16 Mg ha−1 (MSWC) applied for three consecutive years (2012 to 2015). Our results revealed that compost and chemical fertilizer had significant effect on soil organic carbon, soil aggregate stability indices, soil water retention, transmission characteristics, and pore size distribution. This improvement in soil physical properties imparted into better soil physical environment and significant reduction in soil salinity (75%) was apparent with application of MSWC. Multivariate analysis indicated that mean weight diameter (MWD) and retension pores (RP) were the two main soil physical properties that help to reduce soil salinity. Our results revealed that, MWD increased by 49.1% in MSWC and 37.7% in GEC over control (C) (0.53 mm). Improvement in soil environment under composted soil produced significantly higher grain yield of mustard (2.22 Mg ha−1) and pearl millet (2.29 Mg ha−1) with MSWC as compared to control (C). Organic amendments significantly improved the soil physical environment.

EFFECT OF CLIMATE CHANGE ON GRAPEVINES PHENOLOGICAL STAGES AND YIELD UNDER ARID ENVIRONMENT

Climate change is a dramatic crisis that has left severe impacts on the agricultural sector and especially on viticulture. Phenological sets over 41 years and annual climatic anomalies ’data over the same years’ intervals were procured. An earliness in Al Ahsa region, the first signs of climate change were detected starting 1997, where annual precipitable water and temperature anomalies were the most important climate influencers all phenological events occurred for the varieties White and Red, from the beginning of budburst until harvest. Moreover, the yield of both varieties was slightly reduced between 1997 and 2019 in comparison with the interval of years 1979-1996. Beginning of budburst, budburst, 2-3 leaves unfolded and visible inflorescence were positively correlated with the annual wind speed anomaly. Beginning of flowering, full flowering, beginning of fruit set, full veraison, and harvest were positively with the annual total cloud cover anomaly and annual total precipitation anomaly. In addition, the full fruit set and beginning of veraison were positively correlated with annual wind speed anomaly, and negatively correlated with annual precipitable water anomaly. Yield was positively correlated with annual total precipitation anomaly and annual total cloud cover anomaly. Results suggest the adoption of a drip irrigation system in Al Ahsa vineyards that would overcome the low water availability in hot summers and reduce soil salinity, one of the biggest issues facing Gulf countries.

Effect of Organic Amendments and Nano-Zinc Foliar Application on Alleviation of Water Stress in Some Soil Properties and Water Productivity of Barley Yield

The scarcity of water resources in arid and semi-arid areas is considered a threat to agricultural sustainability. Therefore, approaches are needed to rationalize use of irrigation water without reducing crop productivity or degrading soil properties. The objective of this study was to investigate the effect of different organic amendments (O1 = control, O2 = compost, and O3 = vermicompost) combined with different rates of nano- zinc foliar spraying (Zn1 = 0, Zn2 = 1 and Zn3 = 2 gm/L), under irrigation supplements (I1 = 100%, I2 = 85%, and I3 = 65% of water requirements) on clay soil characteristics, on the production of Egyptian barley Giza 126. Over two successive winter growing seasons, 2018/2019 and 2019/2020, field experiments were conducted as a split-split plot design with three replications. The results show that using vermicompost is an appropriate organic amendment to improve the physical and chemical properties of soils as compared with compost. Application of vermicompost led to a reduction in soil salinity (ECe), exchangeable sodium percentage (ESP), and soil bulk density (BD), of −5.67%, −5.44%, and −2.21%, respectively; there was a significant increase in soil organic carbon (SOC), available nitrogen (A.N), and field capacity (F.C.), of 43.75%, 14.37%, and 18.65%, respectively, compared with unamended soil (O1). The maximum values for grain yield were increased by 13.2% and 14.9% in both seasons, respectively, and the irrigation water productivity of barley was increased more than compost and control. Vermicompost increased the irrigation water productivity for grain (1.69 and 1.69 kg grain m−3) and straw (1.23 and 1.17 kg straw m−3) in the first and second season, respectively. Similar trends were also observed from treatments on the water applied, stored water, and water application efficiency. Application of vermicompost and nano-Zn foliar spraying could be exploited for the development of barley growth and yield, which are enhanced under water-saving irrigation strategies.

Monitoring and Modeling of Saline-Sodic Vertisol Reclamation by Echinochloa stagnina

Soil salinity due to irrigation is a major constraint to agriculture, particularly in arid and semi-arid zones, due to water scarcity and high evaporation rates. Reducing salinity is a fundamental objective for protecting the soil and supporting agricultural production. The present study aimed to empirically measure and simulate with a model, the reduction in soil salinity in a Vertisol by the cultivation and irrigation of Echinochloa stagnina. Laboratory soil column experiments were conducted to test three treatments: (i) ponded bare soil without crops, (ii) ponded soil cultivated with E. stagnina in two successive cropping seasons and (iii) ponded soil permanently cultivated with E. stagnina with a staggered harvest. After 11 months of E. stagnina growth, the electrical conductivity of soil saturated paste (ECe) decreased by 79–88% in the topsoil layer (0–8 cm) in both soils cultivated with E. stagnina and in bare soil. In contrast, in the deepest soil layer (18–25 cm), the ECe decreased more in soil cultivated with E. stagnina (41–83%) than in bare soil (32–58%). Salt stocks, which were initially similar in the columns, decreased more in soil cultivated with E. stagnina (65–87%) than in bare soil (34–45%). The simulation model Hydrus-1D was used to predict the general trends in soil salinity and compare them to measurements. Both the measurements and model predictions highlighted the contrast between the two cropping seasons: soil salinity decreased slowly during the first cropping season and rapidly during the second cropping season following the intercropping season. Our results also suggested that planting E. stagnina was a promising option for controlling the salinity of saline-sodic Vertisols.

Elaeagnus angustifolia can improve salt-alkali soil and the health level of soil: Emphasizing the driving role of core microbial communities

Saline-alkali environments are widely distributed in China and significantly hinder the development of agriculture. This study characterizes the long-term effects of planting Elaeagnus angustifolia (E. angustifolia) on the physical and chemical properties, enzyme activities and microbial community characteristics of saline-alkali soil in the Songnen Plain (1, 2 and 3 years). The results showed that planting E. angustifolia reduced soil pH and electrical conductivity (EC) and increased soil total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (Nni), total potassium (TK), dissolved organic C (DOC), dissolved organic matter (DOM) and available potassium (AK) content and catalase, urease, polyphenol oxidase, phosphatase, sucrase and cellulase enzyme activities, and the results peaked in the 3 year. High-throughput sequencing showed that the bacterial abundance and diversity were as follows (from high to low) y3 > y2 > y1 > CK. E. angustifolia resulted in an increase in the relative abundance of the dominant bacteria. Proteobacteria and Pseudomonas were the major phylum and genus, respectively. Redundancy analysis showed that changes in the soil microbial community significantly affect the physical and chemical properties of the soil, with Proteobacteria members being the key microorganisms that reduce soil salinity. Network analysis showed that Pseudomonas (Proteobacteria) participated in the synthesis of key soil enzymes. 16S rRNA sequencing predicted that the expression of genes related to carbon (rbcL, acsA, acsB, Pcc and accA) and nitrogen (amoA/B, nxrA, hao, gdh, ureC and nosZ) transformation increased, and Pseudomonas members were key regulators of carbon and nitrogen dynamics. In conclusion, the planting of E. angustifolia could improve the physical and chemical properties of the soil by releasing root exudates into the soil and increasing the diversity and richness of soil microbial communities to improve saline-alkali soil, providing a theoretical basis for improving saline-alkali soil and promoting the sustainable development of modern agriculture.

Maize productivity response to combined tillage and mulching in coastal saline zones

AbstractSoil salinization is threatening sustainable crop production in coastal saline regions. An integrated approach with combined tillage and mulching may be more successful than sole management practice (e.g., rotary tillage) for reducing soil salinity and improving crop productivity in coastal saline zones. We conducted a 3‐yr field experiment in maize (Zea mays L.) in the Yellow River Delta. We used four treatments: (a) rotary tillage to 15 cm (RT) (local farmers’ practice), (b) deep tillage to 25‐to‐30‐cm depth followed by RT (DT), (c) flat planting with the application of plastic mulch after DT (DM), and (d) ridge‐furrow planting together with plastic mulching after DT (DMF). These treatments were intended to improve soil properties and maize productivity, while increasing net returns. Grain yields were significantly increased by 18.5–20.9% under DMF and DM, nitrogen partial factor productivity (PFPN) by 18.5–20.8%, and net returns by US$103–124 ha–1, compared with RT. Grain yields with DMF and DM were also improved by 12.7–15.0%, PFPN by 12.8–15.0%, and net returns by $ 39–60 ha–1, compared with DT. Compared with RT, soil electrical conductivity (EC) and Na+ concentration with DMF and DM were reduced by 16.2–75.4% and 19.0–78.2%; EC and Na+ concentration were also reduced by 6.41–64.4% and 11.1–53.7%, compared with DT. These results demonstrate that combined tillage and mulching is an efficient integrated management approach for improving soil properties, promoting maize productivity, and increasing financial benefits in coastal saline zones.

Effect of Smashing Ridge Tillage Depth on Soil Water, Salinity, and Yield in Saline Cotton Fields in South Xinjiang, China

To explore the potential of smashing ridge tillage irrigation, it is necessary to investigate how smashing ridge tillage technology with mulched drip irrigation affects soil water, salinity, and cotton yield in saline fields. We conducted a two-year (2020–2021) field experiment to study the effects of different smashing ridge tillage depths on soil bulk density, moisture, salinity, dry matter production, yield, and its constituents (effective bolls, 100-bell weight). There were three smashing ridge tillage depths: A (20 cm), B (40 cm), and C (60 cm), with traditional tillage as the CT. The results showed that all of the smashing ridge tillage could reduce soil bulk density, improve the utilization and uptake of deep soil water during the rapid growth period, and reduce the soil salt content. Compared with the CT treatment, the average soil bulk density of the 0–60 cm soil layer in treatments A, B, and C in 2020 and 2021 decreased by 3.05%, 5.87%, 10.09%, and 1.65%, 4.48%, and 8.49%, respectively. The average soil water content in the 0–120 cm soil layer at the flowering and boll stage decreased by 3.68%, 6.28%, 9.04%, and 3.59%, 6.52%, and 9.98%, respectively; the soil salt content in the 0–120 cm soil layer at the boll opening stage decreased by 4.21%, 6.75%, 11.95%, and 5.47%, 24.25%, and 54.13%, respectively. Cotton dry matter production and yield tended to increase with an increasing depth of smash ridge tillage. Treatment C obtained the maximum dry matter production, seed cotton yield, effective bolls, and 100-boll weight. The dry matter production at the boll opening stage was significantly increased by 17.16% and 15.91%, and the yield was significantly increased by 65.24% and 84.14% in treatments C in 2020 and 2021, respectively, compared to CT. The smashing ridge tillage of 60 cm can optimize the structure of the soil tillage layer and also reduce soil salinity and increase yield, which is the suitable depth of smashing ridge tillage for saline cotton fields in the south of Xinjiang. The findings of the study can provide some theoretical basis and practical experience for the improvement of saline soils and sustainable agricultural development in South Xinjiang, China.

Efficient irrigation management in sugarcane cultivation in saline soil

ABSTRACT The objective of this study was to evaluate the influence of leaching fraction on the biometric and production characteristics and technological quality of the juice of sugarcane varieties grown in saline soil in the Brazilian semiarid region. The experimental design was in randomized blocks, with three repetitions, in a 2 × 3 × 3 factorial scheme, corresponding to two sugarcane cultivation cycles: plant cane and ratoon cane; three sugarcane varieties: RB72454, SP943206 and VAT90212; and, three leaching fractions of irrigation water: 0; 9.1; and 16.6%. Number of living leaves, number of internodes, leaf area, stem diameter, plant height, number of tillers, yield, total soluble solids content (°Brix), percentage of industrial fiber, juice purity, juice Pol%, cane Pol% and total recoverable sugar were evaluated. At the end of the two crop cycles, water use efficiency was determined. The varieties SP943206 and VAT90212 showed higher yield under leaching fraction of irrigation water of 9.1% in both cycles, and higher water use efficiency values were observed for the variety VAT90212. Application of leaching fractions to reduce soil salinity does not promote changes in the technological quality of the sugarcane varieties RB72454, SP943206 and VAT90212.

Optimization of irrigation and nitrogen fertilization increases ash salt accumulation and ions absorption of drip-fertigated sugar beet in saline-alkali soils

• Irrigation and nitrogen effects on dry matter, ash salt accumulation, irons uptake of sugar beet were explored. • Dry matter and ash salt accumulation, Na + , K + , Ca 2+ and Mg 2+ uptake of W 3 were smaller than those of W 1 and W 2 . • Ash salt accumulation, Na + , K + , Ca 2+ and Mg 2+ uptake were proportional to dry matter accumulation. • Binary quadratic equations were fitted between water-nitrogen inputs and dry matter, ash salt accumulation and irons uptake. Sugar beet ( Beta vulgaris L.), as a salt-tolerant plant, has been widely cultivated in saline-alkali soils, e.g. southern Xinjiang of China, due to its effective capability of reducing soil salinity. A two-year field experiment was conducted on drip-fertigated sugar beet under plastic mulch to explore to effects of three irrigation amounts (W 1 : 0.60 ET c , W 2 : 0.80 ET c and W 3 : 1.00 ET c , where ET c is the crop evapotranspiration) and six nitrogen application rates (N 1 : 25 kg N ha −1 , N 2 : 60 kg N ha −1 , N 3 : 120 kg N ha −1 , N 4 : 240 kg N ha −1 , N 5 : 360 kg N ha −1 and N 6 : 480 kg N ha −1 ) on sugar beet growth, ash salt accumulation, plant Na + , K + , Ca 2+ and Mg 2+ uptake. The results showed that the year and the two-way interaction of irrigation and nitrogen fertilization had significant effects on dry matter, ash salt accumulation, plant Na + , K + , Ca 2+ and Mg 2+ uptake, but there was no significant effect of the three-way interaction of year, irrigation and nitrogen fertilization on ash salt accumulation, plant Ca 2+ and Mg 2+ uptake. The dry matter, ash salt accumulation, Na + , K + , Ca 2+ and Mg 2+ uptake of N 1 were significantly lower than those of other treatments. Nitrogen fertilization increased the dry matter and ash salt accumulation, Na + , K + , Ca 2+ and Mg 2+ uptake of sugar beet. The ash salt, K + and Ca 2+ were mainly distributed in the leaf and petiole, while Na + and Mg 2+ were mainly distributed in the taproot. Among the four ions, the average contents of K + and Na + were larger in all treatments, which were 1.79 % and 1.62 % in the two years, respectively. The average content of Mg 2+ was 0.36 % in all treatments in the two years, and the average content of Ca 2+ was lowest in all treatments, which was 0.14 % in the two years. Compared to W 1 and W 2 , W 3 decreased the dry matter and ash salt accumulation, plant Na + , K + , Ca 2+ and Mg 2+ uptake. The ash salt accumulation, plant Na + , K + , Ca 2+ and Mg 2+ uptake increased with the increasing dry matter accumulation. Based on the response surface methodology, the relationships between water-nitrogen inputs and dry matter, ash salt accumulation, plant Na + , K + , Ca 2+ and Mg 2+ uptake were established. The results can provide a theoretical basis for the phytoremediation of sugar beet in southern Xinjiang of China and maybe elsewhere with similar arid and semi-arid climates.

THE IMPORTANCE OF PHYTOMELIOR PLANTS IN IMPROVING LAND RECLAMATION

Drought-tolerant, salt-tolerant phyto-reclamation plants such as Maksar and White corn should be planted as secondary crops to prevent the devastation of grain-free areas and the deterioration of the reclamation status of these areas. We think these are good results. For example, white corn can be harvested as a minor crop while maintaining good soil moisture until the fall months and reducing soil salinity.

Opportunities and risks with early sowing of sunflower in a salt-affected coastal region of the Ganges Delta

On low-lying land in the Ganges Delta, waterlogging, salinity, and poor soil structure are constraints to intensifying cropping systems. Early sowing of dry season (rabi) crops in this area is hypothesized to increase yield potential because the current late sowing exposes the crop to less favourable temperature conditions, soil dryness, and salinity stresses. Field experiments were conducted over 2 years to identify the opportunities and challenges of early sowing between mid-November and mid-December for maximizing sunflower yield in Southern Bangladesh. Sunflower was dibbled into untilled wet soil on five occasions (23 and 30 November and 10, 20, and 30 December in 2016–2017 and 25 November, 14 and 25 December, and 10 and 25 January in 2017–2018), with two mulching treatments (rice straw at ~ 5 t ha−1 and 15–20% rice residue retention). Sowing before 15 December was associated with larger heads, more seeds per head, greater seed weight, and higher grain yield (3.5–4 t ha−1) in the first year, but early sowing was also risky since, in the second year, the sunflower sown on 25 November was hampered by heavy rainfall, which depressed yield compared to crops sown on 15 December. Increased yield from early sowing before 15 December was associated with higher soil water, lower soil salinity, and higher solute potential compared to sowing after 15 December. Lower yield in late sown crops was also associated with increased temperature at grain-filling stage. The rice straw mulch significantly improved soil water availability, reduced soil salinity, increased soil solute potential, and increased yield in the second year. In this paper, we show for the first time that sunflower sown before 15 December in the Ganges Delta has higher yield potential, but to gain the benefits of the earliest sowing, growers will need to manage the increased risk of yield loss due to waterlogging.