Use of langbeinite to reclaim sodic and saline sodic soils

Abstract

Langbeinite is a soluble potassium‐magnesium sulfate mineral (K₂SO₄2MgSO₄) found as an evaporite in many regions of the world. Langbeinite was used as a reclaiming material in a fine textured (clay loam) saline sodic soil (Grabe Series). This amendment can be dissolved and directly into the irrigation water, displacing sodium (Na) quickly with minimal water use. This amendment was superior over gypsum as a reclaiming material for a saline sodic soil in batch, column, and greenhouse studies. Langbeinite required 50% less irrigation water than gypsum to displace and leach exchangeable Na from soils. Langbeinite improved the infiltration rates of saline sodic soils, but not as effectively as gypsum. Significant increases in germination percent dry matter production mass of lima bean (Phaseolus lunatus L.) plants were observed when using langbeinite over the gypsum soil amendment.     

耕作改制对砂姜黑土微量元素的影响研究

研究旱作改水旱轮作对砂姜黑土中微量元素含量、有效性和赋存形态等的影响结果表明,砂姜黑土旱作改水旱轮作后,微量元素的总含量除Mo外,均呈贫化趋势且达显著水平;Cu、Fe、Mn和Mo的有效性明显提高,Zn的有效性降低,严重缺Zn可能限制作物产量提高;残留态、晶形铁态和碳酸盐态微量元素含量随旱作改水旱轮作时间的延续而降低,有机态和无定形铁态微量元素的含量则不断增加,代换态微量元素含量变化与有效态微量元素相似,呈两极分化,Cu和Ni增加,而Zn和Mn降低.     

Effect of flooding on physico-chemical changes in sodic soils

Laboratory experiments were conducted with sodic soils of varying exchangeable sodium percentage (ESP) (82, 65, 40, and 22) and a normal soil (ESP 4) to study the changes with time in soil pH, pCO₂, Fe²⁺ and Mn²⁺ under submerged conditions with and without 1.0 per cent rice husk. In all the soils pCO₂, Fe²⁺ and Mn²⁺ increased after flooding, reached the maximum value and then either maintained or declined slightly. The release of Fe²⁺ and Mn²⁺ was maximum in normal soil and decreased with increase of ESP in sodic soils. Addition of rice husk brought about a conspicuous increase in Fe²⁺ and Mn²⁺, the maximum increase being in lowest ESP soil. Flooding reduced the pH of all soils. The effect was more pronounced in the presence of rice husk. The kinetics of pCO₂ indicated that accumulation of CO₂ was higher in normal soil and least in highest ESP soil. The addition of rice husk showed an average increase of 0.0074 atm pCO₂ in comparison to rice husk untreated soils.     

The effect of lime and compost amendments on the potential for the revegetation of metal-polluted, acidic soils

The revegetation of soils affected by the historic pollution of an industrial complex in central Chile was studied. Spontaneous and assisted revegetation and changes in the physicochemical properties of the soils were evaluated in field plots that were amended with lime or lime + compost. Lime had no effect on plant productivity in comparison with the control, whereas the incorporation of lime + compost into the soil increased the plant cover and aboveground biomass. The application of lime + compost increased the plant productivity of Chrysanthemum coronarium (a species sensitive to the atmospheric emissions from the industrial complex), thus showing effective in situ stabilization of soil contaminants. Regression analyses suggested that the plant response was due to the increase in the soil organic matter content rather than to the increase in the soil pH. The aboveground biomass and plant cover did not differ under the spontaneous and assisted revegetation regimes. The native soil seed bank was sufficient for attainment of the proper plant cover and biomass production after the application of the soil amendments. Although the pCu²⁺ in the amended soils was 4 orders of magnitude higher than in the unamended control, the shoot Cu concentration was similar among most of the combinations of plant species and amendments.     

Exchange-induced dissolution of gypsum and the reclamation of sodic soils

A study was undertaken to define the dissolution kinetics of gypsum in the presence of ion exchange resins and to study sodic soil reclamation in laboratory soil columns.
Gypsum pellets were prepared at 1.5 MPa pressure and the time course of their dissolution followed by measuring the electrical conductivity of the solution. Dissolution experiments were carried out in distilled water with and without Na- and Cl-saturated exchange resins or a combination of the two. The results indicate that in the presence of resin the reaction is first order as calcium and/or sulphate are removed from solution by the resin driving the reaction to completion. In water alone the reaction follows second-order kinetics and depends on the rate of mixing as the reaction is transport controlled.
The effect of gypsum placement (uniformly mixed with the entire soil, mixed with the top third of the soil, applied to the soil surface or applied as a saturated gypsum solution) on the efficiency of exchangeable sodium removal, leaching of soluble salts and soil hydraulic conductivity was studied. In addition, the effect of various flow rates on reclamation efficiency was investigated.
The amount of leachate required for reclamation was found to be dependent on gypsum placement, tending to decrease in the order mixed < top third mixed < saturated gypsum solution < gypsum surface application < water. Soil hydraulic conductivity was much higher in the mixed gypsum column than in the gypsum applied on the surface; a result of the higher effective gypsum solubility. Sodic soil electrical conductivity in the presence of solid-phase gypsum is linearly related to the total amount of exchangeable sodium expressed in mol dm⁻³.     

Ameliorative effect of K-type and Ca-type artificial zeolites on the growth of beets in saline and sodic soils

Abstract

Beets were grown on soils with various exchangeable sodium percentages (ESP). A saline non-sodic soil (SA, ESP = 3.2), a saline sodic soil (SO, ESP = 23), and a saline high sodic soil (HSO, ESP = 78) were prepared from Tottori sand dune soil (CO). K-type and Ca-type artificial zeolites (50 g kg^?1) were applied to these soils in order to evaluate their effects on the chemical properties of saturation extracts of the soils, water deficit, cation uptake and transport, and cation balance of beet plants. In the zeolite-free treatments, beet growth was accelerated in SA and SO, but was suppressed in HSO compared with CO. The addition of both types of zeolites ameliorated plant growth in all the soils studied, especially HSO. The relative dry weight of the soils treated by the K-type zeolite to the zeolitefree soil was 189% for CO, 125% for SA, 130% for SO, and 222% for HSO. For the soils treated with the Ca-type zeolite, the values were 169, 116, 132, and 341%, respectively. In SA, SO, and HSO, the addition of the K-type zeolite increased the K uptake due to the increase of the K concentration of saturation extracts of soils. The addition of the Ca-type zeolite increased the Ca uptake due to the increase in the Ca concentration of the saturation extracts of soils which was accompanied by an increase in the K uptake. The increase in the uptake of K or Ca and decreased in the transport of Na by the addition of both types of zeolites improved the cation balance of the plants. The Ca-type zeolite did not increase the water deficit even though it increased the electric conductivity in all the soils. The results indicated that both types of artificial zeolites were able to improve the growth performance of beets in saline and sodic soils and that the K-type zeolite could be used as a K-fertilizer as well.     

Fungal community composition in sodic soils subjected to long-term rice cultivation

ABSTRACT

Rice cultivation is widely used to improve saline-sodic soils in Northeast China. However, the chronological effect of rice cultivation on soil fungal communities has not been studied. Therefore, this study investigated the variation of soil fungal communities in different rice cultivation years. Compared with the blank area, the rice cultivation for 20 years significantly decreased the pH and electrical conductivity by 16.6% and 70.1%, while significantly increased the soil organic carbon and available phosphorus by 90.6% and 17.4 times, respectively. Meanwhile, the relative abundance of Ascomycota and Basidiomycota significantly decreased and increased after rice cultivation, respectively. Moreover, some genera of arbuscular mycorrhizal fungi (AMF), e.g. Corymbiglomus, Glomus, and Rhizophagus, and pathogenic fungi (Thanatephorus cucumeris) disappeared, while Dentiscutata (one genus of AMF) appeared after rice cultivation. In addition, the fungal richness significantly increased when the rice cultivation less than 15 years and the fungal communities were similar between 15 and 20 years. Our findings showed that rice cultivation improved the nutrient availability and reduced salinity-alkalinity stress of sodic soils. After the rice cultivation for 15 years, the soil fungal community tended to be stable.     

The response of finely textured and organic soils to lime and phosphorus application: Results from an incubation experiment

A soil's responses to phosphorus (P) input differs based on its chemical composition. Soil acidity and the presence of metallic cations dictate a soil's chemical composition. Currently, soil P application recommendations are universal and do not account for differing soil composition. A targeted soil-specific approach is required to optimize P efficiency and availability. A pot incubation experiment was established to explore the effects of contrasting lime and P application rates across a range of soils (25), characterized by fine particle size and high levels of soil organic matter. Three contrasting rates of P were applied (0, 50, and 150 kg P ha⁻¹) both with and without ground lime (CaCO₃) at 5 tonne ha⁻¹ over a 140-day incubation period. The addition of lime buffered the soil, increasing nutrient availability and reducing P fixation. The 50 kg P ha⁻¹ treatment rate was required to achieve sufficient plant available P in both mineral soil textural classes. Current legislative recommendations however do not allow the application of such rates, which has an impact on agronomic performance. Loam soils experienced a greater increase in M3 soil P in comparison to clay and organic soils. Organic soils posed a major threat to water quality due to poor P retention. A re-evaluation of P recommendations is required to account for soil variability as current P allowances are insufficient on these particular soils.     

Influence of forest tree species on reclamation of semiarid sodic soils

Tree plantation is a proven strategy to improve the salt‐affected soils. However, the efficiency of trees to reclaim the soil varies from species to species. This study was therefore, carried out with the objective of assessing the efficiency of 3‐yr old plantations of Prosopis juliflora (Swartz) D.C. (Mesquite), Eucalyptus tereticornis Sm. (Forest Red Gum) and Dalbergia sissoo Roxb. Ex. D.C. (Indian Rosewood) to improve the sodic soil characteristics in Sultanpur districts of Uttar Pradesh, India (26°10′–26°23′N, 81°50′–82°5′E). Soil samples collected from six depths; 0.0–0.1, 0.1–0.3, 0.3–0.6, 0.6–0.9, 0.9–1.2 and 1.2–1.5 m below the surface, were analysed for chemical and physical properties by following standard methods. The infiltration rate (IR) was determined by double concentric infiltrometer and the permeability by constant head permeameter. The trees were measured for their girth at breast height (at 1.33 m from ground) and crown area within a 100 × 100 m sector at each of the sites selected. There were decreases in soil pH (from 10.06 to 9.64) and exchangeable sodium percentage (from 70.6 to 26.9) at the P. juliflora plantation relative to the E. tereticornis and D. sissoo plantations. The organic carbon and nitrogen content increased from 2.0 and 0.18 g/kg to 3.9 and 0.45 g/kg under P. juliflora at the surface (0.0–0.1 m) layer. There was also more exchangeable Ca²⁺, Mg²⁺and K⁺ at exchange sites and a reduction in exchangeable Na⁺ 3 yr after establishing the plantations. There was a significant decrease in surface soil (0.1 m) bulk density from 1.66 to 1.37 (t/m³) but an increase in porosity from 41.2 to 46.3% and water holding capacity from 4.3 to 4.8 g/kg. The IR and soil permeability also increased after 3 yr of tree growth. Prosopis juliflora proved more effective than E. tereticornis and D. sissoo in its ability to enrich a sodic soil with organic matter and establishing better soil–water characteristics.     

Waterlogging effects on elemental composition of wheat genotypes in sodic soils

Waterlogging + sodicity proved more harmful than sodic or waterlogging stress individually. Wheat genotypes were evaluated for waterlogging tolerance in neutral (pH 7.8) and sodic (pH 9.3) soils. There was 50% greater reduction in overall grain yield when genotypes were waterlogged for 15 days in sodic soil than in neutral soil. This was associated with proportional reductions in biomass and productive tillers. Severe effects of waterlogging were observed on grain yield in sodic soil and the extent of damage depends heavily on the stage of development, duration, and temperature. Waterlogging reduced the concentration of macro elements (K, Ca, and Mg), whereas effects on microelements concentration were mixed, with some elements increasing (Fe, Al, Mn, and Na) and others decreasing (Cu and Zn). Significant genotypic variation was observed for grain yield and biomass under the stress treatments and KRL 3–4, KRL 99, KRL 210, and Kharchia 65 were the top performers.     

石灰氮对土壤中尿素转化的影响

Laboratory incubation experiment was conducted to study the effect of lime nitrogen(LN) on transfor-mation of urea-N in three paddy soils.The results showed that LN had an inhibitory effect on urease activity in these soils especially in the first 5 days.and that in the first 20 days of incubation,the amount of NH4^ -N derived from urea was lower in the soil with LN than in the soil without LN,While after 30 days the amount of NH4^ -N was higher in the mature haplic paddy soil developed on Quaternary red clay (MHPS)with LN than that in the soil without LN.The amount of NH3-N volatilized was decreased in the earlier stage and increased in the later stage of incubation in the MHPS by the addition of LN.     

The effect of lime levels on the growth of beans and maize and nodulation of beans in three tropical acid soils

Abstract

A study to investigate the effect of lime on dry matter yield of maize (Zea mays) and beans (Phaseolus vulgaris) and nodulation of beans grown in three tropical acid soils (two humic Nitosols and one humic Andosol) was carried out in a greenhouse. The soils ranged from 4.2 to 5.0 in pH; 1.74 to 4.56 in %C; 21.0 to 32.0 meq/100g in CEC; 5.10 to 8.10 meq/100g in exchange acidity; 0.60 to 3.20 meq/100g in exchangeable (exch.) Al and 0.13 to 0.67 meq/ 100g in exch. Mn.

Exchange acidity and exch. Al decreased with increasing levels of lime in the three soils. Exchangeable Al was reduced to virtually zero at pH 5.5 even in the soils which had appreciable initial amounts. Exchangeable Mn also decreased with increasing levels of lime in the two Nitolsos. Exceptional results, however, were obtained with the Andosol where exch. Mn increased ten‐fold with the first level of lime and then decreased with subsequent levels.

In all the soils, mean dry matter yield of beans and maize, and mean nodule dry weight of beans generally increased significantly with increasing lime levels up to pH value of 6.0. The dry matter yield of beans and maize, and nodule weight of beans, however, decreased progressively with increasing lime levels beyond pH 6.0 value. pH range of 5.5 to 6.0 was considered optimum for the growth of maize and beans, and nodulation of beans in these soils.     

Driving forces for sodium removal during phytoremediation of calcareous sodic and saline–sodic soils: a review

Abstract. Sodic and saline–sodic soils are characterized by the occurrence of sodium (Na⁺) at levels that result in poor physical properties and fertility problems, adversely affecting the growth and yield of most crops. These soils can be brought back to a highly productive state by providing a soluble source of calcium (Ca²⁺) to replace excess Na⁺ on the cation exchange complex. Many sodic and saline–sodic soils contain inherent or precipitated sources of Ca²⁺, typically calcite (CaCO₃), at varying depths within the profile. Unlike other Ca²⁺ sources used in the amelioration of sodic and saline‐sodic soils, calcite is not sufficiently soluble to effect the displacement of Na⁺ from the cation exchange complex. In recent years, phytoremediation has shown promise for the amelioration of calcareous sodic and saline–sodic soils. It also provides financial or other benefits to the farmer from the crops grown during the amelioration process. In contrast to phytoremediation of soils contaminated by heavy metals, phytoremediation of sodic and saline–sodic soils is achieved by the ability of plant roots to increase the dissolution rate of calcite, resulting in enhanced levels of Ca²⁺ in soil solution to replace Na⁺ from the cation exchange complex. Research has shown that this process is driven by the partial pressure of CO₂ (P_CO2) within the root zone, the generation of protons (H⁺) released by roots of certain plant species, and to a much smaller extent the enhanced Na⁺ uptake by plants and its subsequent removal from the field at harvest. Enhanced levels of P_CO2 and H⁺ assist in increasing the dissolution rate of calcite. This results in the added benefit of improved physical properties within the root zone, enhancing the hydraulic conductivity and allowing the leaching of Na⁺ below the effective rooting depth. This review explores these driving forces and evaluates their relative contribution to the phytoremediation process. This will assist researchers and farm advisors in choosing appropriate crops and management practices to achieve maximum benefit during the amelioration process.     

Selection of Leucaena species for afforestation and amelioration of sodic soils

Performance of three exotic species of Leucaena (L. diversifolia, L. shannonii and L. leucocephala) and one local selection of L. leucocephala was evaluated on sodic soil sites (pH 8.6–10.5) in order to select promising species for biomass production and reclamation of these soils. There were significant differences among three species with respect to their field survival (47.7–95.5 per cent), growth in terms of stem volume (40.8–118.6 m³ ha⁻¹) and biomass production (24–70 Mg ha⁻¹) after eight years of growth. L. leucocephala was rated as the most promising species irrespective of seed source, followed by L. shannonii. L. diversifolia could not perform well on these hostile soils. A definite improvement in physicochemical properties of soil particularly in surface layers (0–5 cm) was observed after eight years of plantations as compared to the same at uncultivated site. The soil pH and sodium content decreased followed by an increase in organic carbon, nitrogen and phosphorus content. However, efficiency of different species varied greatly to ameliorate these soils depending on quantity and quality of organic matter lying on the floor. L. leucocephala, irrespective of seed origin, showed greater promise for afforestation of sodic soils because of its potential to produce higher biomass per unit area and greater efficiency to ameliorate fertility status of these soils. The study revealed that matching of species to soil conditions is very important for a successful plantation programme and sustainable development of degraded soil sites. Copyright © 2002 John Wiley & Sons, Ltd.     

苏打碱土盐分淋洗与饱和导水率的关系

土壤饱和导水率是土壤重要的物理性质之一,反映了土壤入渗和渗漏性质,是计算土壤剖面水通量和排水工程设计的一个重要土壤水力参数[1]。准确地估测农田饱和导水率,对于制定正确的水分和盐分、水分和养分的管理措施及有效地防止污染物对环境的影响,都有十分重要的意义。已有研究表明,饱和导水率受土壤质地、结构、盐分含量与组成、容重或孔隙度、土壤水分特征等诸多因素影响[2-7]。就碱土而言,饱和导水率低是其标志性特征之一[8-10],提高饱和导水率是有效淋洗碱土盐分的基本前提[11]。松嫩平原是国内仅次于黄淮海平原的第二大平原,其西部是中国五大盐渍土分布区域之一[12]。土壤盐分以NaHCO3和NaCO3为主[     

耕作改制对砂姜黑土中锰的影响

研究砂姜黑土旱改水对土壤中Mn含量、赋存形态和有效性的影响结果表明,砂姜黑土中Mn存在于粘土矿物、晶形氧化铁、无定性氧化铁、氧化锰态、有机物和碳酸盐中比例分别为27.19%~46.26%、10.48%~21.65%、2.76%~12.28%、17.39%~26.53%、10.61%~24.57%和0.16%~8.35%。旱改水实施水旱轮作后砂姜黑土中全Mn含量极显著降低,平均降幅为8.77%,但伴随土壤pH值的趋中性,土壤中Mn由植物有效性较低的晶形铁结合态逐渐向植物有效性较高的氧化锰态、无定形铁态和有机态转化,活化了土壤中的Mn,提高了Mn的有效性和可移动性。     

Amelioration of calcareous saline sodic soils through phytoremediation and chemical strategies

Abstract. The worldwide occurrence of saline sodic and sodic soils on more than half a billion hectares warrants attention for their efficient, inexpensive and environmentally acceptable management. These soils can be ameliorated by providing a source of calcium (Ca²⁺) to replace excess sodium (Na⁺) from the cation exchange sites. Although chemical amendments have long been used to ameliorate such soils, the chemical process has become costly during the last two decades in several developing countries. As a low‐cost and environmentally acceptable strategy, the cultivation of certain salt tolerant forage species on calcareous sodic and saline sodic soils, i.e. phytoremediation, has gained interest among scientists and farmers in recent years. In a field study conducted at three calcareous saline sodic sites (pH_s=8.1–8.8, EC_e=7.8–12.5 dS m^–1, SAR=30.6–76.1) in the Indus Plains of Pakistan, we compared chemical and phytoremediation methods. There were four treatments; two involved plants: Kallar grass (Leptochloa fusca (L.) Kunth), and sesbania (Sesbania bispinosa (Jacq.) W. Wight). The other two treatments were uncropped: soil application of gypsum and an untreated control. All treatments were irrigated with canal water (EC=0.22–0.28 dS m^–1). The plant species were grown for one season (5–6 months). Sesbania produced more forage yield (34 t ha^–1) than Kallar grass (23 t ha^–1). Phytoremediation and chemical treatments resulted in similar decreases in soil salinity and sodicity, indicating that phytoremediation may replace or supplement the more costly chemical approach. The soil amelioration potential of sesbania was similar to that of the Kallar grass, which suggests that moderately saline sodic calcareous soils can be improved by growing a forage legume with market value.     

The effects of lime on adsorption and desorption of phosphate in five Colombian soils

The effects of lime (applied in the field) on the amounts of total and isotopically-exchange-able phosphate adsorbed from solutions were measured in five soils. The total amount of phosphate adsorbed without lime was in the range 200 to 1700 μg P per g of soil at 0.05 μg P cm⁻³ of solution. Lime diminished the amount of phosphate adsorbed at all concentrations of solution in an oxisol and a dystropept; in an ultisol and another dystropept, lime tended to increase sorption at small concentrations and diminish it at large concentrations; in a dystrandept that contained spheroidal allophane and a great deal of organic matter, lime increased adsorption at all concentrations up to 1 μg P cm⁻³. Lime increased the proportion of added phosphate that was isotopically exchangeable in the oxisol and one dystropept, had no effect in the other dystropept, and diminished the proportion in the ultisol and dystrandept.
Adsorbed phosphate was subsequently desorbed by suspending the soils in solutions without phosphate. After desorption the quantity of exchangeable phosphate in all soils was closely correlated with aluminium extracted by ammonium oxalate; buffer power was correlated in all except the dystrandept, in which it was larger per unit of aluminium than in the other soils; possibly the cause was aluminium associated with organic matter. In all soils lime diminished buffer power allowing a specific amount of exchangeable phosphate to maintain a larger concentration in solution. The beneficial effects of lime on exchangeable phosphate after desorption were consistent among soils, despite inconsistent results when the phosphate was adsorbed.     

Driving factors determining the occurrence of sodic soils in dry subhumid Mediterranean areas

An evaluation of the factors determining the occurrence and the properties of soils with low permeability occurring in vast areas in S Portugal was carried out taking into account the terrain morphology and the geology of the region. This paper deals with the variation patterns of the physical and chemical characteristics of soils from several soil toposequences that occur under different gradient slopes and on different parent rocks. Spatial variation of soil properties mainly depends on the composition of their cation‐exchange complex, as the role of other factors, such as the mineralogy of the clay fraction, were of minor importance. There is often a stronger increment of Na and/or Mg than of Ca with depth, causing a variable degree of sodicity in some of these soils, to which waterlogging tendency of their upper horizons is related. Though the occurrence of these features is determined by the nature of the parent rock, their degree of expression varies primarily according to the topographic position of soils. Therefore, a catenary distribution including nonsodic Cambisols or Luvisols in the hillcrests and Stagnic Solonetz or Sodic Luvisols or Sodic Stagnosols in the topographic lows is common. Such soil characteristics are of utmost importance for irrigation suitability and management of these soils, and for environmental impacts assessment, as the region is vulnerable to desertification.