Phosphorus leaching from clay soils can be counteracted by structure liming

Two field experiments with drained plots on clay soils (60% and 25% clay) demonstrated a significant reduction in leaching of total phosphorus after application of structure lime. Aggregate stability was significantly improved. Phosphorus leaching in particulate form was significantly reduced following structure liming at the site with a very high clay content. Sites representing low (50 mg kg^?1) and high (140 mg kg^?1) levels of phosphorus extractable with acid ammonium lactate in topsoil displayed differing effects on leaching of dissolved reactive P (DRP). This form of phosphorus was only significantly reduced compared with the control at one site with high topsoil phosphorus status and relatively high (17–18%) degree of phosphorus saturation in the subsoil. Laboratory experiments with simulated rain events applied to topsoil lysimeters from the same site also demonstrated a significant reduction in leaching of DRP. These findings indicate that structure liming is an appropriate leaching mitigation measure on soils with both a high clay content and high soil phosphorus status.     

Liming reduces nitrogen uptake from chemical fertilizer but increases that from straw in a double rice cropping system

Liming materials are widely applied to alleviate soil acidification and increase rice yield in acidic soils, but their effects on nitrogen (N) use efficiency are still unclear. Here, we conducted a field-, pot-, and micro-plot experiment to investigate how the application of slaked lime (i.e., Ca(OH)₂) affects the fate of chemical fertilizer-N and straw-N in a double rice cropping system. In the field experiment, liming increased grain yield and N uptake by an average of 9.0% and 10.6%, respectively. In contrast, CaCl₂ application did not affect rice yield and N uptake, suggesting that the effects of lime application were not related to the addition of Ca²⁺. Results from a ¹⁵N tracer experiment (i.e., ¹⁵N-labeled urea and straw) indicated that liming reduced N uptake from fertilizer (−5.7%), but increased N uptake from straw (+31.3%). Liming also reduced soil retention of both urea- and straw-N and increased their loss rates. Taken together, our results indicate that although liming increases rice yield and N uptake, it lowers the use efficiency of fertilizer N and facilitates N losses. In addition, our results emphasize the need for long-term studies on the impact of liming on soil N dynamics in paddy soils.     

Response of Mature Phosphorus-Deficient Apple Trees to Phosphorus Fertilization and Liming

ABSTRACT

The aim of the study was to examine response of mature phosphorus (P) deficient apple (Malus domestica Borkh.) trees to phosphorus fertilization and liming. The experiment was carried out during 2003–2005 in a commercial orchard in Central Poland on ‘Jonagold’ apple trees/M.26 planted in 1996 on a coarse-textured soil with low both pH (4.6) and organic matter (1.2%). Calcium-lactate soluble phosphorus concentration in the soil was within an optimal range despite appearance of leaf phosphorus deficiency symptoms. Soil and foliar applications of phosphorus, and soil liming were applied. Soil phosphorus fertilization was made in the first year of the experimental at a rate of 100 kg P per ha as triple superphosphate. Foliar sprays of a soluble compound containing organic phosphorus were performed 5 times per season at 2-week intervals, starting 4 weeks after full bloom. Soil liming was applied in the fall 2002 at a rate of 1100 kg Ca ha^?1 as hydrated lime. Additional combination as soil phosphorus fertilization plus liming was also applied. Plots unsupplied with phosphorus and lime served as a control. The results showed that liming and liming plus soil P application increased soil pH, and phosphatase activity in the soil, and improved phosphorus nutrition, tree vigor, yield, fruit color, and firmness after storage; effect of these treatments was not found only in the first year of the study. In all years foliar phosphorus sprays improved phosphorus nutrition of apple trees, and fruit color and firmness after storage. In 2 out of 3 years foliar phosphorus application increased yield. The vegetative and reproductive responses of ‘Jonagold’ apple trees did not depend on soil phosphorus fertilization. It was concluded that maintaining an optimal pH of soils for apple trees limits the incidence of orchard phosphorus deficiency and that foliar phosphorus sprays should be applied in phosphorus-deficient apple orchards to improve yield, and fruit appearance and storability.     

Effects of lime,phosphorus, manganese,copper, and zinc on plant mineral composition,yield of itarley,and level of extractable nutrients for an acid Swedish mineral soil

Abstract

A pot experiment was performed during the 1992 growing season on an acid, sandy topsoil taken from a Swedish liming experiment. A central composite experimental design was used in order to study the effects of supply of phosphorus (P) and micronutrients at different liming levels on yield of barley (Hordeum vulgare L. c.v. Golf), mineral content in plant, straw, and grain, and level of soil extractable nutrients. The results showed no increase of yield due to liming despite the fact that lime increased the yield significantly in the field experiment. The soil appeared initially to have a good balance between the nutrients included in the experimental design with the exception of P. An excessive supply of manganese (Mn) decreased the yield. The contents of calcium (Ca) and aluminum (Al) in the plant were hardly affected by the treatments, while the contents of P, Mn, copper (Cu), and zinc (Zn) more than doubled compared to no supply. The contents of P, Cu, and Zn were mainly influenced by the supply of the actual element, while the content of Mn was more closely related to the supply of lime. Soil pH(H₂0) and CaCl₂‐extractable P, Mn, Cu, and Zn were highly related to the supplies of lime, P, Mn, Cu and Zn, respectively. Only a few interactions were observed.     

Effect of liming and phosphate application on sudangrass growth and phosphorus availability in two temperate acid soils

Abstract

A pot experiment was carried out in the greenhouse with two loamy sand Dystric Cambisols derived from schist to investigate the effect of liming and phosphorus (P) application on plant growth and P availability and its assessment by four soil test methods: 0.01M calcium chloride (CaCl₂), cation anion exchange membrane (CAEM), Egnér‐Riehm, and Olsen procedures. Soils were first incubated for two weeks with lime at four levels, depending on their content of exchangeable aluminum (Al). Phosphorus was added at two rates (75 and 150 mg P kg^‐1) and the incubation proceeded for an additional two‐week period. Sudangrass (Sorghum sudanenses cv. Tama) was then planted and harvested four weeks later. During incubation and plant growth, soils were maintained at 70% of field moisture capacity. Although pH value and soil extractable P in original soils were similar, the results showed a significant difference on the effect of liming and P application. Acidity was the major limitation for DM yield in the soil with the highest amount of exchangeable Al, while P availability was the main constraint in the other soil. Liming above pH (0.01M CaCl₂) 5.3–5.5 did not increase DM yield in either soil and showed a negative effect on one soil (9.7 to 6.9 and 10.2 to 7.8 g pot^‐1). Phosphorus content and uptake by sudangrass increased with liming, revealing a positive effect of lime on the availability of P to plants. Added P showed a lower efficiency in the soil with highest amounts of Al compounds. Soil tests performed after the execution of the pot experiment showed variable tendencies to predict P availability, according to the nature of the procedures and soils. Soluble‐P in 0.01M CaCl₂ increased with the rise of soil pH. Extractable CAEM‐P and Egnér‐Riehm‐P also increased with liming, but reflected the soil depletion caused by plant uptake. Extractable Olsen‐P presented the most inconclusive results, suggesting the limitation of this method for acid soils which have been limed.     

Effects of long-term contrasting lime and phosphorus applications on barley grain yield,root growth and abundance of mycorrhiza

Lime and phosphorus (P) applications are common agricultural management practices. Our aim was to quantify the effects of long-term application practices on root growth and abundance of arbuscular mycorrhizal fungi (AMF) under field conditions. We assessed the effects of lime and P fertilizer applications on barley yield, root growth and AMF abundance in 2016. Treatments were no, low, medium and high liming rate corresponding to application of 0, 4, 8 and 12 Mg lime ha⁻¹ every 5–9 years since 1942 combined with no or yearly application of 15.6 kg P ha⁻¹ since 1944. At harvest, grain yield, root intensity (core-break) and AMF abundance at different soil depths were estimated. Root development was monitored during early growth with minirhizotrons in treatments receiving low, medium and high liming rates and P fertilization. A quadratic model relating grain yield to liming rate estimated yields to peak at 6.4 Mg lime ha⁻¹ with yields of 4.2 and 3.2 Mg grain ha⁻¹ with and without P fertilization, respectively. Low and medium liming rates resulted in greater AMF abundance, especially in the no P treatments. During early growth in P-fertilized treatments, 77% and 65% more roots developed in the soil profile when treated with medium and high liming rate, respectively, compared to low liming rate. We conclude that long-term application of lime in soils receiving yearly P fertilization improved conditions for root growth in soil layers below 30 cm, but at the high liming rate, this did not translate into higher yield.     

Organic Lettuce Growth And Nutrient Uptake Response To Lime,Compost And Rock Phosphate

Fertilizer recommendations are needed to increase organic vegetable yields. Thus, organic lettuce growth and nutrient uptake was investigated in a randomized block pot experiment with twelve treatments from the factorial structure of three factors: (i) Gafsa phosphate [0 and 200 kg phosphorus pentoxide (P₂O₅) ha^?1], (ii) compost from source separated municipal organic waste (0, 15, and 30 t ha^?1) and (iii) limestone [0 and 8 t ha^?1 calcium carbonate (CaCO₃) equivalent]. Lettuce yield increased with compost application and a first order interaction between lime and phosphate was clear because lime partially replaced the need for phosphate. This was explained by the effect of liming on P availability in acid soils. Nitrogen (N), phosphorus (P), and potassium (K) accumulation increased in lettuces produced with compost or phosphate but only the accumulation of N was increased with lime. This compost is recommended to increase nutrient availability for organic lettuce whereas the need for phosphate fertilization may decrease with liming.     

Liming effects on soil pH and crop yield depend on lime material type,application method and rate,and crop species: a global meta-analysis

Purpose

The aim of this meta-analysis was to investigate the interactive effects of environmental and managerial factors on soil pH and crop yield related to liming across different cropping systems on a global scale.

Materials and methods

This study examined the effects of liming rate, lime application method, and liming material type on various soil chemical properties and crop yield based on data collected from 175 published studies worldwide since 1980.

Results and discussion

The most important variables that drive changes in soil pH and crop yield were liming rate and crop species, respectively. Soil conditions, such as initial soil organic matter and soil pH, were more important for increasing soil pH in field-based experiments, while lime material type and application method were more important for improving crop yield. To effectively neutralize soil acidity, the optimum liming duration, rate, and material type were?<?3 years, 3–6 Mg ha^?1, and Ca (OH)₂, respectively. Averaged across different crop species, the application of CaO, CaCO₃, Ca (OH)₂, and CaMg (CO₃)₂ increased yield by 13.2, 34.3, 29.2, and 66.5%, respectively.

Conclusions

This meta-analysis will help design liming management strategies to ameliorate soil acidity and thus improve crop yield in agroecosystems.

     

Investigation into the effect of tillage on solute movement to drains through a heavy clay soil

Abstract. Eight lysimeters, each with a surface area of 0.5 m² and a length of 60 cm, were taken over mole drains from a Denchworth soil and divided into two groups with either a standard agricultural tilth or a finer, deeper topsoil tilth. They were variously instrumented to measure soil moisture content at three depths and losses of nitrate, a bromide tracer and radiolabelled isoproturon, all of which were followed over a year. Leaching of isoproturon was initiated by artificial irrigation either 1 or 39 days after application. The finer tilth seemed to increase the water-holding capacity of the topsoil, and this resulted in slower wetting of the subsoil, decreased flow volumes from the first events of the season and a delay of approximately four weeks in the time to the maximum concentration of the bromide tracer in leachate. The finer topsoil tilth also decreased maximum concentrations of isoproturon from 29 to 15 μg l⁻¹ following irrigation 1 day after treatment and from 43 to 9 μg l⁻¹ following irrigation 39 days after treatment. Total losses of isoproturon were three times larger with the standard agricultural tilth. Differences were attributed to a decrease in bypass flow through the topsoil with the finer tilth, particularly during events early in the season. There was a small decrease in total losses of nitrate in leachate from the finer tilth compared to that from the standard tilth.     

Growth and nitrogen fixation by subterranean clover in response to inoculation,molybdenum application and soil amendment with lime

Liming an acid soil increased the yield and N content of subterranean clover in both field and glasshouse experiments. Application of Mo increased the N concentration of field-grown subterranean clover which corresponded with observed colour and growth differences, but did not change C₂H₂ reduction activity. Herbage Mo was not increased by liming, suggesting an absolute deficiency of Mo in these acid soils. In the glasshouse liming increased nodulation which increased the amount of N₂ fixed but the lime had no direct effect on nitrogenase activity as measured by C₂H₂ reduction. In the field both inoculation and lime application increased soil populations of R. trifolii, but clover yield was greater with liming alone than with inoculation alone, indicating the sensitivity of the host plant to soil acidity.     

Liming and nitrogen efficiency: Some effects of increased calcium supply and increased soil pH on nitrogen recovery by perennial ryegrass

Abstract

Positive effects of liming on the nitrogen (N) contents of perennial ryegrass (Lolium perenne) shoots might be due in part to the effects of increased exogenous calcium (Ca) level on the rate of N uptake by plants. To test this hypothesis, perennial ryegrass was grown in soil culture treated with different rates of lime, gypsum, and ammonium nitrate (NH₄NO₃), in a factorial combination. The effects of these treatments on yield, N offtake, and shoot chemical composition were examined at two consecutive harvests. At both harvests, liming significantly increased plant yield and N offtake. There was no response to gypsum at cut 1; but at the second harvest, a negative interaction occurred between the two Ca treatments such that gypsum increased plant yield and N offtake in the absence of lime but not in its presence. The results suggest that liming affects N recovery by swards in at least two different ways, each associated with a different phase in the soil MIT (Mineralization Immobilization Turnover) cycle. During phases of net N mineralization, liming by raising soil pH stimulates biomass activity and increases the amount of organic N mineralized. In contrast, during phases of net N immobilization, liming by increasing Ca availability in the rhizosphere improves the ability of plants to absorb N, and thus helps them to compete more effectively with the biomass for mineral N.     

Optimal Acidity Indices for Soybean Production in Brazilian Oxisols

Soybean is an important crop for the Brazilian economy, and soil acidity is one of the main yield-limiting factors in Brazilian Oxisols. A field experiment was conducted during three consecutive years with the objective to determine soybean response to liming grown on Oxisols. Liming rates used were 0, 3, 6, 12, and 18 Mg ha^?1. Liming significantly increased grain yield in a quadratic trend. Ninety percent maximum economic grain yield (2900 kg ha^?1) was achieved with the application of about 6 Mg lime ha^?1. Shoot dry weight, number of pods per plant, and 100-grain weight were also increased significantly in a quadratic fashion with increasing liming rate from 0 to 18 Mg ha^?1. These growth and yield components had a significant positive association with grain yield. Maximum contribution in increasing grain yield was of number of pods per plant followed by grain harvest index and shoot dry weight. Uptake of nitrogen (N) was greatest and phosphorus (P) was least among macronutrients in soybean plant. Nutrient-use efficiency (kg grain per kg nutrient accumulation in grain) was maximum for magnesium (Mg) and lowest for N among macronutrients. Application of 3 Mg lime ha^?1 neutralized all aluminum ions in soil solution. Optimal acidity indices for 90% of maximum yield were pH 6.0, calcium (Ca) 1.6 cmol_c kg^?1, Mg 0.9 cmol_c kg^?1, base saturation 51%, cation exchange capacity (CEC) 4.8 cmol_c kg^?1, Ca/Mg ratio 1.9, Ca?/?potassium (K) ratio 5.6, and Mg/K ratio 3.0.     

稻草与生石灰添加介导的温室内土壤团聚体稳定性及碳分布特性

土壤中稳定的团聚体为碳的固定提供良好的物理保护,同时土壤中的碳又会促进团粒结构的形成,二者相辅相成,但在长期稻草和生石灰添加介导的设施内土壤中二者如何变化,却少见报导。以长期施肥定位试验为依托,采用湿筛法研究了施用鸡粪(M)的基础上,配施稻草(R)和生石灰(Ca)对设施土壤团聚体组成、稳定性及碳分布的影响,以不施肥(CK)为对照。结果表明:(1)在鸡粪基础上加入稻草(MR)或生石灰(MCa),与单施鸡粪(M)相比,0.25mm团聚体含量分别增加了123%和37%;稻草和生石灰同时添加可显著增加5~2mm大团聚体含量,较MR、MCa、M分别提高12%,59%,141%。(2)在鸡粪基础上施入稻草或生石灰均可增加MWD、GMD、R_(0.25),提高团聚体的稳定性,其中MR处理最高,MRCa处理次之,二者均显著高于MCa、M、CK处理。(3)在鸡粪基础上加入稻草或生石灰,均可提高土壤全碳含量,其中MRCa处理最高,较MR、MCa、M分别增加20%,40%,55%;稻草和生石灰同时施入可显著增加5~2mm大团聚体中碳含量;加入生石灰可增加0.5~0.25mm团聚体中碳含量;施入稻草或生石灰均可显著增加0.25mm团聚体中的碳对土壤全碳的贡献。(4)土壤全碳含量与5~2,2~1,1~0.5mm团聚体含量呈显著正相关,与0.25mm微团聚体含量呈显著负相关;MWD、GMD、R_(0.25)均与0.25mm团聚体含量呈显著正相关,与0.25mm微团聚体含量呈显著负相关。设施土壤在施入鸡粪的基础上同时加入稻草和生石灰,可改善土壤结构,提高土壤碳水平,有利于缓解设施生产中因长期连作所导致的土壤结构劣变问题。     

Effects of reduced tillage and liming on microbial activity and soil properties in a weakly-structured soil

The effects of reduced tillage and lime on crop yield and soil physical and microbial properties were studied in a weakly-structured silty clay loam soil. Two autumn primary tillage practices were compared, mouldboard ploughing to 20–25 cm and cultivation to 12 cm. Seedbed preparation was carried out by several harrowing operations in the mouldboard ploughed treatment, and with a PTO-driven harrow in the same operation as sowing in the shallow cultivation treatment. The tillage treatments were applied alone or were combined with liming aimed at soil structural improvement. Lime was added as 6.5 Mg CaO ha⁻¹ before the start of the experiment and mixed into the top 12 cm of soil with a disc cultivator. A 4-year crop rotation was used: spring barley, spring oilseed rape, spring/winter wheat and oats, and all crops were compared each year. Crop residues were retained in the experiment and incorporated at cultivation. Aggregate stability was improved by the shallower tillage depth, probably as an effect of an increase in soil organic matter and a more active microbial biomass. Liming had little effect on soil structure variables but increased microbial activity to some extent. This was reflected in higher crop yields, especially when the shallow tillage depth was combined with liming. Penetration resistance in the seedbed subsoil was highest when mouldboard ploughing was carried out in plots without liming. Data were examined with principal component analyses, and the structures in the data were presented as scores and loading plots, which revealed groupings between samples and relationships between variables, respectively.     

Effect of calcitic and dolomitic lime on physicochemical properties of a Chilean Andisol

Abstract

Changes in surface reactivity produced by different types of liming in a Chilean Andisol were determined. Barros Aranas soil with 53% aluminum (Al) saturation and 4.8 pH was incubated with different amounts of calcitic and dolomitic lime. Each cmol of calcitic or dolomitic lime applied per kg of soil increased the pH with 0.13 and 0.16 units, respectively. Consequently, the decrease in Al saturation was higher with dolomitic than with calcitic liming material. The zero point of charge (ZPC) increased from 4.2 in unlimed soil to 4.6 and 4.8 in limed soil, while the point of zero salt effect (PZSE) decreased from 4.5 to 4.0 and 3.5 with calcitic and dolomitic lime, indicating an increase in negative charge. But, isoelectric point (IEP) values measured by electrophoretic migration suggested that the external charge only changed by treatment with calcitic liming materials. In both treatments, the acidity constant decreased, and consequently phosphorus (P) adsorption capacity also decreased.     

Liming Potential of Composts Applied To an Acid Oxisol in Burundi

The adverse effect of soil acidity on plant growth and yield, and the scarcity of commercial agricultural lime (CaCO₃) in Burundi necessitated a search for alternative liming materials. Thus, the liming potential of locally made composts was evaluated in a greenhouse experiment, using an acid Oxisol with sorghum (Sorghum vulgaris) as a test plant. Application rates were 10 g/kg (approximately 20 ton/ha) for the composts and 0, 0.85 and 1.70 g/kg for Verrundi lime. Results showed that the application of lime increased plant growth by reducing exchangeable Al, and by increasing soil pH and available P. So did the composts, which were more effective in correcting soil acidity when they were fresh and enriched with some nutrients during the composting process. Apparently, organic molecules produced by the composts helped to chelate and/or precipitate Al, making the soil more suitable for plant growth. Specifically, an application of 20 ton/ha of composts was equivalent to 0.6 - 1.7 ton CaCO₃/ha, depending on the compost quality.     

Direct experimental evidence for the contribution of lime to CO2 release from managed peat soil

Liming is a common management practice used to achieve optimum pH for plant growth in agricultural soils. Addition of lime to the soil, however, may cause CO₂ release when the carbonates in lime dissolve in water. Although lime may thereby constitute a significant carbon source, especially under acidic soil conditions, experimental data on the CO₂ release are lacking so far. We conducted a split-plot experiment within a cut-away peatland cultivated with a bioenergy crop (reed canary grass, Phalaris arundinacea L.) with lime and fertilizer treatments to determine effects of lime on the CO₂ emissions from soil and to better understand mechanisms underlying liming effects. Carbon dioxide release was measured over two growing seasons in the field after liming, and complementary laboratory studies were conducted. To differentiate CO₂ derived from lime and biotic respiration the δ¹³C of CO₂ released was determined and the two-pool mixing model was applied. The results showed that lime may contribute significantly to CO₂ release from the soil. In the laboratory, more than 50% of CO₂ release was attributable to lime-carbonates during short-term incubation. Lime-derived CO₂ emissions were much lower in the field, and were only detected during the first (2–4) months after the application. However, a maximum of 12% of monthly CO₂ emissions from the cultivated peatland originated from the lime. Biotic respiration rates were similar in limed and unlimed soils, suggesting that higher pH did not, at least in the short-term, increase carbon losses from cultivated peat soils. Additional fertilization and acidification did not contribute to further CO₂ release from the lime. According to our first estimations about one sixth of the lime applied would be released as CO₂ from the managed peatland, with all lime-derived emissions occurring during the first year of application (equivalent to about 4.6% of the total annual CO₂ losses from the soil in the first year). This suggests that the mass-balance approach as proposed by the IPCC Tier 1 methodology, which assumes that all carbon in lime ends up as CO₂ in the atmosphere, overestimates the emissions from lime. Our study further shows that there is a great risk to overestimate heterotrophic microbial activity in limed soils by measuring the CO₂ release without separating abiotic and biotic CO₂ production.     

Alternative procedure for total phosphorus determination in plant tissue

Abstract

Surface liming will prevent the formation of an ‘acid roof’ on the surface of soil cropped in no‐till corn (Zea mays L.). A study was begun in 1985 to determine the effectiveness of unincorporated liming in raising pH in no‐till soil which had developed significant acidity throughout the upper 15 cm. Lime was applied at 0, 3.36, 6.72 and 10.08 Mg ha^‐1. All lime was applied on 26 April 1985 and was not incorporated. The pre‐liming pH at 0‐5 cm below the surface was 4.5; after two months the pH was raised to 5.6, 5.8, and 6.0 by 3.36, 6.72 and 10.08 Mg ha^‐1 of lime, respectively. After 19 months soil‐pH was raised to 6.0, 6.4 and 6.6 by liming at 3.36, 6.72 and 10.08 Mg ha^‐1 respectively. Soil‐pH below 5 cm was not affected by any rate of lime during the first 19 months after liming. Tissue analysis of corn ear leaves indicated that calcium uptake was increased significantly by lime in 1985, while manganese uptake was significantly reduced. In 1986, increases in calcium were greater than in 1985 and addtional significant reduction in manganese uptake was accompanied by significantly reduced zinc and copper uptake. In both 1985 and 1986, a trend toward lower average corn grain yield in unlimed plots than in limed plots was noted, but the yield increases due to lime were not statistically significant in either year. This study will be continued as a long term investigation of lime penetration into no‐till soil and response of corn to soil‐pH changes.     

Effect of liming central European loess soils on soil extractable phosphorus and potassium as determined by electro-ultrafiltration

The benefits of liming acidic or calcium (Ca)-deficient soils for soil structure and fertility are well documented. However, little is known about the effect of liming nearly neutral loess soils – lacking Ca – on interactions between soil nutrients. Over a 2-year period, 62 field trials were conducted in Germany and Austria with three treatments (0, 3 and 12 t CaO ha^?1) on slightly acidic loess soils. Soil samples from the top soil layer were taken 4, 8, 16 and 24 weeks after liming. In addition to the pH_CaCl2, the phosphorus (P), potassium (K) and Ca contents were analysed using electro-ultrafiltration (EUF). The application of lime increased the pH in average from 6.6 up to 7.0 and 7.2, but did not decrease EUF extractable P and K below the level of untreated control. Contrary to our expectations, EUF extractable P increased 4 weeks after liming in the treatment with 3 t CaO ha^?1. At the end of incubation period, 24 weeks after liming, the EUF extractable K in treatment 12 t CaO ha^?1 remained still 1.3 mg K 100 g^?1 soil above the untreated control.     

Effectiveness of some local liming materials in Nigeria as Ameliorants of soil acidity

The effectiveness of three local liming materials: basic slag (a byproduct of iron and steel industry), cement flue dust (a waste product of cement factory), and ground limestone was compared with that of imported hydrated lime in a greenhouse study using acid soils from two sites in Southern Nigeria. The soils were taken from Onne, near Port Harcourt in Rivers State and Epe near Lagos in Lagos State. The soils were classified as Typic paleudult and Typic udipsamment, respectively. The results show that the four liming materials were capable of neutralizing soil acidity. Their relative effectiveness was in the order: hydrated lime > basic slag > cement flue dust > ground limestone. Uptake of phosphorus (P), potassium (K), and calcium (Ca), and dry matter yield increased with increasing lime rates up to 500 and 1,000 mg Ca/kg soil for Epe and Onne soils, respectively. The lime requirements of the two soils are in the order of the aluminum (Al) saturation of the effective cation exchange capacity (ECEC) and are equivalent to exchangeable Al multiplied by 1.74 and 1.50, respectively. While differences among lime rates were significant for nutrient uptake and dry matter yield, there were no significant differences among the lime sources.