Reclamation Of Sodic Soils Research Articles

Characterization and Mapping of Soil Salinity Status at Small-Scale Irrigation Farm: The Case of Fantale Irrigation Project Sites

Agricultural production and productivity can be adversely affected by the presence of excessive salts in soils particularly in semi-arid and arid areas. Knowledge of the salinity/sodicity of the soil and the quality of the irrigation water is essential for managing agricultural fields effectively and increasing the output and productivity of the lands. This research was initiated with the objectives of characterizing and Mapping of soil salinity status at small scale irrigated areas of Fantale district and identifying the most affected irrigation scheme so as to design appropriate soil salinity management. The study was conducted at Fentale district of Galcha, Gola and Dire Sade irrigation schemes. Soil samples were collected from the surface using augur, and from pits at different depth interval and analyzed for pH, EC, Na+, ESP, SAR, Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup>, and CEC. The result was compared with the standards set by FAO system to classify soil and water salinity. Accordingly, it was identified that Galcha irrigation scheme was characterized as sodic due to very strong sodium concentration with average ESP of 53.2% and EC 3.95 mmhoms/cm and pH about 9.25. On the other hand, Gola and Dire Sade Irrigation schemes were characterized as moderately and slightly sodic respectively. Sodium was the dominant soluble cation, followed by calcium, magnesium, and potassium in all soil depths and schemes. Beside primary Salinization of natural processes such as physical or chemical weathering parent material, and discharge Basaka Lake to the downstream, was the main source of salt build-up in the upper layers of the soil at Galcha irrigation scheme. On the other hand, irrigation water analysis indicated that water used for irrigation at all irrigation schemes were slightly sodic. Therefore, the study underscores the need for a scientific reclamation of sodic soils primarily at Galcha Irrigation scheme where sodium concentration in the soil was very strong.

Occurrence of Sphingomonas olei with elemental S oxidation capability in sodic soil: Potential role in sodicity reclamation and plant growth promotion

The success of the sodic soil reclamation using elemental S (S°) depends on the population of the native S° oxidizers. Augmenting the native flora of the sodic soils with effective S° oxidizers can enhance the success of the sodic soil reclamation. Present study reports for the first time the S° oxidation potential of the Sphingomonas olei strain 20UP7 isolated from sodic soils with pHs 9.8 and ECe 3.6 dS m–1. Inoculation with S. olei strain 20UP7 caused 13.0–24.2 % increase in S° oxidation in different sodic soils (pHs 9.1–10.5). It improved the concentration of the Ca2+, Mg2+, PO43– and declined the HCO3– and total alkalinity of the soil solution. This isolate also showed appreciable P and Zn solubilization, indole acetic acid, ammonia, and titratable acidity production in the growth media. It tended to the formation of biofilm around sulphur particles. The PCR amplification with gene–specific primers showed the occurrence of soxA, soxB, and soxY genes with a single band corresponding to length of 850, 460, and 360 base pairs, respectively. The integration of the S. olei strain 20UP7 with S° caused 21.7–25.4 % increase in the rice and wheat yield compared to the soil treated with S° alone. This study concludes that the S. olei, native to high saline–sodic soils can be utilized for improving the sodicity reclamation and plant growth promotion using elemental S based formulations.

Reusing drainage water for leaching of saline and sodic soils in the Khuzestan province, Iran

ABSTRACT This study investigates the feasibility of utilizing drainage water for reclamation of saline and sodic soils in the Dosalagh plain of Khuzestan province, Iran. With significant drainage water generated in the region's irrigation networks, repurposing it for soil reclamation emerges is a low-risk strategy. Leaching, a practical technique for soil desalination, was examined using the double ring method at depths up to 150 cm. Four water qualities (electrical conductivities of 2.12, 7, 25 and 40 dS m−1) and depths (0, 25, 50 and 75 cm) were tested, with intermittent leaching over three cycles. Results indicate a substantial reduction in electrical conductivity (117.7 to 29 dS m−1) and sodium content (1415.9 to 39.83 mEq L−1) at the 0-25 cm depth with drainage water incorporation. The study highlights the beneficial impact on soil quality, emphasizing decreased sodium content, sodium adsorption ratio, and electrical conductivity. Overall, reusing drainage water proves advantageous for soils with high salinity levels, showcasing its potential for sustainable soil management in saline regions. This research underscores the importance of effective drainage water management for soil reclamation and agricultural sustainability in arid regions like Khuzestan province.

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

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

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

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

Characterization of flue gas desulphurized (FGD) gypsum of a coal-fired plant and its relevant risk of associated potential toxic elements in sodic soil reclamation.

Thermal Power Plant generates FGD gypsum as by-product during coal combustion. This study evaluates the characterization (spectroscopic and elemental), potentially toxic elements (PTEs) distribution, and environmental risk assessment of FGD gypsum for safe and sustainable use in agriculture. The XRD and SEM analysis confirmed the dominance of crystalline CaSO4·2H2O in FGD gypsum. The order of concentrations of PTEs in FGD gypsum was Fe > Al > Mn > Zn > Ni > Co. The residual fraction was the dominant pool, sharing 80-90% of the total PTEs. The heavy metals (HMs) were below the toxic range in the leachates. The Co, Ni, Al, Fe Mn, Zn had low (< 10%) risk assessment code and the ecotoxicity was in the range of 0.0-7.46%. The contamination factor was also low (0.0-0.16) at the normal recommended doses of FGD gypsum application for sodicity reclamation. The enrichment factor was in the order of Al < Mn < Co < Zn < Ni. Mn [enrichment factor (Ef) 1.2-2.0] and Co (Ef 1.7-2.8) showed negligible enrichment of metals, whereas Ni (Ef 4.3-5.2) and Zn (Ef 4.5-5.6) reported moderate accumulation in soil. The application of FGD gypsum @ 10 t ha-1 for sodicity reclamation will develop a geo-accumulation index below the critical values indicating its safe and sustainable use to achieve land degradation neutrality (LDN) and UN's Sustainable Development Goals.

Rationalizing mineral gypsum use through microbially enriched municipal solid waste compost for amelioration and regaining productivity potential of degraded alkali soils

Reclamation of alkali soils to harness their productivity potential is more complex due to the presence of excess sodium ions, poor hydraulic conductivity and infiltration rate, resulting in poor plant growth and crop productivity. Sodic soil reclamation using inorganic ameliorants like mineral gypsum or phosphogypsum is beyond the reach of small and marginal farmers having alkali soils because of their higher market prices and shortage of availability. Conjoint use of inorganic and organic amendments can be a pragmatic solution for improving soil physico-chemical and biological properties and sustaining crop productivity. Municipal solid waste compost (MSWC) available in abundant quantity if enriched with the efficient halophilic microbial consortium and used in conjunction with a reduced dose of gypsum can be a cost-effective approach for sustainable reclamation of alkali soils and harnessing their productivity potential. Hence, a field experiment was conducted on a high alkali soil (pH2 9.2 ± 0.10), electrical conductivity (EC) 1.14 ± 0.12 dS m−1, exchangeable sodium percentage 48 ± 2.50 and organic carbon (0.30%) was conducted during 2018–19 to 2020–21 to study the combined effect inorganic and organic (enriched municipal solid waste compost (EMSWC)) amendments on amelioration of alkali soils and sustaining productivity of rice–wheat cropping system. Application of gypsum @ 25% GR + enriched MSW compost @ 10 t ha−1 (T6) showed significant improvement in soil physico-chemical and biological properties over the sole application of organic (T3 and T4), inorganic (T2) and control (T1). A significant improvement in soil fertility status in terms of available nitrogen and micronutrients as well as CO3, HCO3, Cl, Ca and Mg content were recorded with the combined application of organic and inorganic soil amendments (T5 and T6) over the sole application of mineral gypsum. Soil microbial biomass carbon (MBC), nitrogen (MBN) and phosphorus (MBP) improved significantly due to the application of EMSWC with gypsum over the application of gypsum only. Grain yield of rice and wheat increased significantly (P < 0.05) owing to the application of a reduced dose of gypsum (25% GR) and EMSWC @ 10 t ha−1 (T6) with values of 5.55 and 3.83 t ha−1, respectively over rest of the treatments. Three years economic analysis of the study revealed that treatments T6 and T5 gave the highest positive net return whereas it was lowest in treatment T1 and negative in treatment T2. The highest benefit-to-cost ratio (B:C) was obtained in treatments T6 and T5 which were significantly higher compared to the rest of the treatments.

Influence of sulphur and gypsum enriched municipal solid waste compost on sodicity reclamation and yield of wheat (Triticum aestivum)

Soil sodicity leads to land deterioration that strongly alters the soil properties and consequently crop productivity. Sustainable management of municipal solid waste (MSW) is another emerging challenge. Combined use of MSW compost enriched with sulphur and gypsum can provide a convincing solution for ameliorating sodic soils and sustaining crop productivity. In this context, a controlled condition study was carried out on composting of MSW alone and its enrichment with elemental sulphur and gypsum followed by evaluation of the efficiency of MSW compost and products of its enrichment for amelioration of sodic soil. A pot experiment was conducted during 2019-20 to 2020-21 at Central Soil Salinity Research Institute, Karnal, Haryana, India on two levels of soil sodicity, namely, highly sodic soil with pH2 of 10.09 and moderate sodic soil with pH2 of 8.72 to evaluate the efficacy of sulphur and gypsum enriched MSW compost on sodic soil reclamation and sustainable yield production of wheat. Four treatments (MSW+ES, MSW+ES+G, MSW+G and MSW compost alone) were applied in different doses in sodic soils under consideration. MSW+ES and MSW+ES+G significantly reduced the soil pH2 up to 13.5 and 13.3%, respectively, Na+ up to 32 and 30% and enhanced grain yield about 44 and 37.2%, respectively, as compared to control (non-amended soil). Out of all amended doses, D3 (@300 g/15 kg soil) was found most effective in reducing pH2 and Na+ about 13.8 and 30.6% respectively. This study has proved that MSW enriched with sulphur can be used as an effective solution for improving soil physico-chemical properties and crop productivity of sodic soil.

Composting of Municipal Solid Waste Using Earthworms and Ligno-Cellulolytic Microbial Consortia for Reclamation of the Degraded Sodic Soils and Harnessing Their Productivity Potential

The management of municipal solid waste (MSW) and the reclamation of degraded sodic soils are two serious environmental and socio-economic problems experienced by the developing nations. To overcome these problems, a technology has been developed for the composting of MSW using earthworm and ligno-cellulolytic microbial consortia and its utilization for the sustainable reclamation of degraded sodic soils, as well as for harnessing their productivity potential. To standardize on-farm composting under aerobic conditions, the field experiment consisted of seven treatment combinations, replicated thrice with municipal solid waste (MSW) sole and in combination with agricultural wastes (AW) treated with earthworms (Eisenia foetida) and consortia of lingo-cellulolytic microbes such as Aspergillus spp., Trichoderma spp. and Bacillus spp. It was conducted at ICAR-CSSRI, Research farm, Shivri, Lucknow, India. The results revealed that the thermophilic phase was achieved at 60 days of composting and thereafter the temperature decreased. Marked changes in pH and EC were found and they changed from acidic to neutral. The reduction in total C, from initial to maturity, varied from 4.45 to 14.14% and the increase in total P and total K from 4.88 to 88.10% and 12.00 to 35.71%, respectively. The nutrient-rich quality compost based on the lowest C: N ratio, highest nutrient contents, microbial population (bacteria and fungi) and enzymatic activities was obtained from a mix of MSW and AW, enriched with earthworms and consortia of lingo-cellulolytic microbes. The efficacy of this enriched compost was evaluated for the reclamation of sodic soils and their potential for sustaining productivity of the rice-wheat cropping system was harnessed through combined application with a reduced dose of gypsum. The results indicated that the application of on-farm compost @10 t ha−1 in conjunction with a reduced quantity of gypsum (25% GR) significantly (p &lt; 0.05) improved the physico-chemical and microbial soil properties, and enhanced productivity of the rice-wheat cropping system over the use of only gypsum. This study proved that on-farm compost of MSW and its utilization for the reclamation of degraded sodic soils can be an alternate solution for useful disposal and management of MSW, thereby improving the health and productivity of sodic soils.

Review of Sodic Soil Reclamation with a Snapshot of Current Research Activity

Review of Sodic Soil Reclamation with a Snapshot of Current Research Activity

Long‐term conservation agriculture helps in the reclamation of sodic soils in major agri‐food systems

AbstractGlobally crop production is impaired by soil salinity and sodicity and to maintain the sustainability of the production systems under such degraded lands, conservation agriculture (CA) may be an alternative in arid and semiarid regions. An experiment was initiated with different agri‐food systems with CA‐based practices to understand the reclamation potential of sodic soil after continuous cultivation for 4 and 9 years. This included: (i) conventional tillage (CT)‐based rice‐wheat system (Sc1); (ii) partial CA with puddled rice‐zero tillage (ZT) wheat and mungbean (Sc2); (iii) ZT rice‐wheat‐mungbean (Sc3); (iv) ZT maize‐wheat‐mungbean (Sc4). Soil samples were collected from 0 to 15 and 15 to 30‐cm depth after 4 and 9 years of wheat harvesting. Results showed an 18% decline in pH2 with Sc2 and ~30% decline in EC2 with Sc2 and Sc3 at upper soil depth after 9 years. Higher cation exchange capacity by 35% and 89% in Sc2 and 38% and 58% in Sc3 after 4 and 9 years was found, respectively, over initial levels. A decrease in exchangeable sodium percentage was recorded in Sc2 by 43% and 50%, after 4 and 9 years over the initial level, respectively. The oxidizable carbon and total organic carbon were increased by ~76%, 69%, and 64% in Sc4, Sc3, and Sc2, respectively, over initial values at 0–15 cm soil depth. Results showed that the CA‐based rice‐wheat‐mungbean system had more reclamation potential than other studied systems. Therefore, long‐term CA practices involving ZT with crop residue recycling and efficient crop rotations have the potential to reduce the sodicity stress and improve soil organic carbon thereby bringing the sodic lands under productive crop cultivation.

Long‐term conservation agriculture helps in the reclamation of sodic soils in major agri‐food systems

Long‐term conservation agriculture helps in the reclamation of sodic soils in major agri‐food systems

Utilization of marine gypsum as an alternative to mineral gypsum in the reclamation of degraded sodic soil and as a means of enhancing crop productivity

AbstractFor sustainable management of degraded sodic soils, mineral gypsum (GYP) has been widely used, but supplies are limited, industrialization, and urbanization have thwarted its use in agriculture. Therefore, there is a need to develop alternative ameliorants to GYP. We conducted a field experiment on degraded sodic soil (pH‐10.2) using marine gypsum (MG), a waste/by‐product of the edible salt (NaCl) manufacturing process. Based on gypsum requirement (GR) of soil, efficacies of GYP and MG, at equivalent doses, were compared for reclamation of sodic soil using treatments: control, 50 GR GYP, 50 GR MG, 25 GR GYP, 25 GR MG, and 25 GR GYP + 25 GR MG. The results showed a significant decrease in soil pH following appliation of 50 GR MG compared with other treatments. The reduction in exchangeable sodium percentage was found and to be highest (50.78%) in 50 GR MG among all treatments but statistically identical to 50 GR GYP. The net dispersive charge we noted was a minimum of 4.04 cmol kg−1 for 50 GR MG but was on par with 50GR GYP and 25GR GYP + 25GR MG. The presence of MgCl2, NaCl, and KCl as impurities in marine gypsum assisted its dissolution by increasing the ionic strength of solution and facilitated Ca2+ release for exchange reactions. We found the average yield of rice and wheat to be statistically similar for applications of 50 GR MG, 50 GR GYP, and 25 GR GYP + 25 GR MG. Thus, our study suggests that MG could effectively be used as an alternative ameliorant for the reclamation of degraded sodic soil without compromising crop yields, under scarce availability of GYP.

Synergizing Microbial Enriched Municipal Solid Waste Compost and Mineral Gypsum for Optimizing Rice-Wheat Productivity in Sodic Soils

Municipal solid waste management and poor fertility status of sodic soils are two important issues experienced by all developing nations including India. Disposal of municipal solid waste (MSW) being produced in huge amounts is a challenging task for researchers and policy makers. Reclamation of salt affected soils with chemical amendments is a costly affair for resource-poor farmers. Composting of MSW and its enrichment with microbes is one of the options for its recycling and utilization for the reclamation of salt-affected soils. A field experiment was conducted in sodic soil to study the performance of microbial enriched municipal solid waste compost (EMSWC) alone and in combination with a reduced dose of gypsum on growth, yield, nutrient uptake, and grain quality of rice and wheat. The experiment was conducted for three consecutive years from 2018 to 2019 and 2020 to 2021 at ICAR Central Soil Salinity Research Institute, Research farm, Shivri, Lucknow, India, in sodic soil having pH 9.2, electrical conductivity (EC) 1.14 dSm−1, exchangeable sodium percentage (ESP) 48, and organic carbon 0.30%. There were six treatments consisting of control, recommended dose of gypsum (50% GR), and enriched and un-enriched MSW compost with reduced dose of gypsum (25% GR). Based on the results pertaining to plant growth, yield-attributing characters, and yields, the treatment T6 (application of microbial enriched MSW compost @ 10 t ha−1 in conjunction with gypsum @25% GR) performed the best. Grain yield of rice and wheat (5.45 and 3.92 t ha−1) with treatment T6 was 29.45% and 110.75% higher over control (T1) and 29.45% and 110.06% over the recommended dose of gypsum (T2). Maximum nutrient content and N, P, and K uptake in rice-wheat grain and straw was observed with the treatment T6 (MSW compost plus gypsum @ 25 GR). However, the highest Na content and Na: K ratio in plant parts were recorded in treatment T2. The highest positive net return and benefit to cost (B/C) ratio were observed in treatment T6 followed by T5 and the lowest in treatment T1 (control), whereas negative return was calculated in treatment of gypsum alone (T2). This shows that the cost of sodic soil reclamation with application of gypsum was not recovered until the second year of cultivation. The results of this study showed significant impacts in MSW management for regaining the productivity potential of sodic soils.

Trichoderma‐primed rice straw alters structural and functional properties of sodic soil

AbstractSodic soil is increasing due to intensive cropping and imbalanced use of agrochemicals. Therefore, the objective of the present study was to reduce the soil sodicity in agricultural fields using sustainable resources. The ‘microbe–residue–soil’ interaction is hypothesized to foster the structural and functional changes during sodic soil reclamation. To elucidate the hypothesis, rice straw (RS) assimilation in sodic soil was instated in the presence of synergistically interacting Trichoderma koningiopsis NBRI‐PR5 (PR5) and T. asperellum NBRI‐K14 (K14) consortium. The interaction of the ‘microbe‐residue‐soil’ was investigated in‐vitro and in sodic fields. Our studies included estimation of soil physicochemical properties, enzymes, CO2 efflux using LI‐COR, microbial population, scanning electron microscopy, and Fourier‐transformed infrared spectroscopy (FTIR) analysis. The compatibility and synergism of PR5 assisted the K14 to produce laccase enzyme at high pH condition (pH 8) to degrade RS in sodic soil. For in vitro and field applications, Trichoderma were colonized on RS (TrichoRS) and applied at 25 t ha−1. Impact of TrichoRS on soil was evident from decreased soil pH (9.6 to 7.8), exchangeable sodium percent (19.6 to 9.9%), increased soil porosity (~53% from 38%), and cation exchange capacity (~twofold). The FTIR showed differences in the stretching of O‐H bonds at 3750–34500 cm−1 indicating the presence of more kaolinite‐type silicates after TrichoRS amendment. Field application of TrichoRS increased the total organic carbon and water‐holding capacity from 0.37% to 1.3% and 34% to 57%, respectively. Increased microbes and urease, protease, and phosphatase activity by 2.72‐, 0.94‐, and 0.88‐times, respectively, ensured nutrient availability. The improved soil properties and ~ 30% increased production justify the hypothesis in providing sustainable reclamation solution for reviving fertility of sodic and intensively cultivated fields.

The Dynamics Characteristics of Soil Water Infiltration and Capillary Rise for Saline–Sodic Soil Mixed with Sediment

Yellow River sediment is the potential resource for saline–sodic soil reclamation. Experiments of one-dimensional soil columns were conducted to investigate the upward and downward soil water transportation characteristics for saline–sodic soil mixed with different sediment addition (0, 10, 20 kg/m2 in the top 20 cm layer). The saturated hydraulic conductivity, ratio of macroporosity, cumulative capillary adsorption and infiltration rate all increased with the increase in sediment addition. No significant differences were detected for both the initial capillary rise rate and the initial infiltration rate for the upward and downward water transportation treatments, respectively. The average adsorption and infiltration rates showed an increasing trend with the increased sediment addition. The initial and average infiltration rates were higher than the initial capillary rise rate and average adsorption rates. The Philip model seems the optimal choice for the dynamic simulation of both upward and downward soil water transportation. The results may provide useful information for soil salinization amelioration.

Efficacy of sulphuric acid and gypsum amendments on sodic soil reclamation under various water regimes

Efficacy of sulphuric acid and gypsum amendments on sodic soil reclamation under various water regimes

Regaining the Agricultural Potential of Sodic Soils and Improved Smallholder Food Security through Integration of Gypsum, Pressmud and Salt Tolerant Varieties

ABSTRACT Accumulation of salts in soils is one of the major challenges for food production in vast areas, and reclamation of these soils is too expensive for marginal farmers. We evaluated the existing practice (EP; gypsum application at 50% gypsum requirement (GR) followed by the cultivation of traditional varieties of rice and wheat) and the improved practice (IP; gypsum application at 25%GR+10 Mg ha−1 pressmud followedby the cultivation of salt-tolerant varieties of rice and wheat) at farmers’ fields in Hardoi district of Uttar Pradesh, India. Effects of these treatments on rice productivity and profitability were evaluated over 3 years from 2011 to 2014. The soils at the study site were sodic (pH 9.2 to 10.4, EC 0.67 to 2.21 dSm−1) with an estimated GR of 8.5 to 13.6 Mg ha−1. All growth parameters recorded at 30-day intervals were significantly higher for IP than for EP, with 36.5% and 39.3% higher straw and grain yields, respectively. Significant interactions between sodicity levels × reclamation practices for grain and straw yields were observed. The use of IP on farmers’ fields with pH values of 9.2, 9.6, 10.0, and 10.4 reduced reclamation costs by 258, 309, 376, and 413 US $ ha−1, respectively. The combination of reduced costs and increased yields in the IP reclamation treatment led to higher returns from rice farming. Because IP effects on yield became better at higher sodicity, only IP led to net profits ≥0 on all sodicity levels within three rice seasons, whereas under EP, this was achieved only for pH levels of 9.2 and 9.6. Soil properties such as pH, EC, organic carbon, and exchangeable sodium percentage (ESP) and contents of cations and anions were improved significantly under IP than under EP. Thus, the improved practice of sodic soil reclamation has contributed substantially to improve the soil health, crop productivity, and farm income. Farm income losses reduced substantially after reclamation of soil and improved the livelihood security of resource poor farmers having salt-affected soils. This study suggested that a large part of agricultural land is being abandoned worldwide due to salinity or sodicity and need to be reclaimed on priority basis to improve the land productivity and farm income of resource-poor farmers.

Effect of nitrogen fertilization on growth, yield and ethanol production of sweet sorghum (Sorghum bicolor (L. Moench)

Field trials were carried out to test the effect of nitrogen fertilization on the growth, stalks and juice yield, sugar content and ethanol production of sweet sorghum. The experiments were carried out on winter 2013 in the Domonstration Farm of the Faculty of Agriculture, University of Khartoum, Shambat and Experimental Farm of the Soba Research Station for Reclamation of Saline and Sodic soils. The treatments comprised the addition of nitrogen fertilizer (urea) at three levels (0, 43 and 86 Kg N ha-1) and two sweet sorghum genotypes (Baladi and RSSS.11), arranged in randomized complete block design replicated 4 times. Results indicated that there were significant (P ≥ 0.05) differences between genotypes in stem diameter at Soba location, stalk height and leaves area at Shambat location, number of green leaves per plant, stalk juice and ethanol yield in both locations. With the genotype RSSS.11 generally superior over genotype Baladi. Nitrogen fertilization increased significantly (P ≥ 0.05) number of green leaves per plant and leaves area at Shambat location and plant height and juice and ethanol yield in both locations. With the Soba location recorded the highest values over Shambat location and 86 kg N ha-1 recorded the highest ethanol yield (255.6l h-1).

Fertility and biochemical activity in sodic soils 17 years after reclamation with flue gas desulfurization gypsum

Previous studies have mainly focused on changes in soil physical and chemical properties to evaluate the reclamation of sodic soils using flue gas desulfurization (FGD) gypsum. However, information on the effects of this reclamation method on microbial-based indicators of soil quality is limited, particularly after many years of FGD gypsum application. This study aimed to investigate the long-term effects of FGD gypsum on soil organic carbon (SOC), nutrients, microbial biomass and enzyme activity. Data were collected from soils of three exchangeable sodium percentage (ESP) classes (i.e., low-, middle- and high-ESP classes of 6.1–20, 20–30 and 30–78.4%, respectively) 17 years after FGD gypsum treatment in Inner Mongolia, China. Averaged across the three ESP classes, FGD gypsum application increased the SOC contents at the 0–20 and 20–40-cm soil depths by 18 and 35%, respectively, and increased available potassium at the 0–20-cm soil depth by 51% compared with the no-gypsum controls. The microbial biomass carbon and microbial biomass nitrogen contents at the 20–40-cm soil depth increased by 69 and 194%, respectively, under FGD gypsum. Except in the high-ESP class, urease activities in the 0–40 cm soil profile were significantly higher in the FGD gypsum treatments than in the controls. A significant increase in alkaline phosphatase activity was concentrated in the 20–40 cm soil layer; few classes showed significant increases in catalase and invertase activities in the 0–20 cm soil layer. Pearson correlation analysis showed that increases in soil fertility and biological activity could be attributed to reductions in electrical conductivity, pH and ESP caused by FGD gypsum application. These results confirm that FGD gypsum application is a viable strategy for reclaiming sodic soils due to its positive effects on soil fertility and biochemistry and that it may contribute to soil ecosystem sustainability.