Lime Requirement Research Articles

Calibrated SoilOptix ® estimates of soil pH and exchangeable cations in three agricultural fields in western Canada – implications for managing spatially variable soil acidity

Spatial variability in soil pH is a major contributor to within-field variations in soil fertility and crop productivity. An improved understanding of the spatial variability of soil pH within agricultural fields is required to determine liming requirements for precision farming. This study with the use of proximal sensors, firstly assessed the spatial pattern of soil pH and how it can be used to determine site-specific, spatially variable lime requirements. Secondly, the effects of soil pH on soil concentrations of nitrate nitrogen (N03-N), phosphorus (P), potassium (K), sulfur (SO4-S), calcium (Ca), magnesium (Mg), soil organic matter (SOM), aluminum (Al), and manganese (Mn) were assessed in three study fields in central Alberta, Canada. Soil pH varied between 4.5 and 7.5 across all field sites. The field-scale coefficient of variation (CV %) for soil pH, Al and Mn ranged between 4.39 and 7.50 %, 7.33–13.72 %, and 7.33–13.72 % across the three sites. The other soil properties showed low, moderate, and high variability, with field-scale CVs ranging between 6.39 and 17.70 % for SOM and 24.33–91.39 % for SO4-S. Soil pH exhibited positive correlations with both Ca and Mg, across all fields. Negative correlations were observed between soil pH and Al across all fields. A principal component analysis (PCA) was performed for all soil parameters and two principal components accounted for 50 %, 54.9 %, and 76.8 % of the total variance in field 1, field 2, and field 3, respectively. Geostatistical semivariance indicated a strong spatial dependence of all chemical parameters across fields. Large regions within a field were strongly acidic (pH < 5.5) and required lime applications ranging from 0 to 6 t ha−1. We conclude that proximal soil sensors can be calibrated to soil properties, enabling variable rate lime recommendations on spatially variable fields for the management of soil acidity.

THE ROLE OF LIMING IN COPPER ADSORPTION OF ACIDIC SOILS

Investigate the impact of varying rates of liming on the availability and sorption properties of copper in a range of acid soils with differing physico-chemical futures. Soil samples with varying acidity levels were collected from different locations in the acidic Black Sea Region of Türkiye. Out of the nine soil samples collected, four were obtained from regions where hazelnuts are grown, while the other five were obtained from areas dedicated to tea growth. The sorption properties of soils limed at 0%, 50%, and 100% of lime requirement and incubated for 12 months, then the Langmuir and Freundlich adsorption isotherms were determined by batch sorption technique. The results showed that increasing the soil pH resulted in an increase in Cu adsorption. Experimental results of Cu adsorption were explained with high coefficients of determination (93.44-98.98%) of the Langmuir model. In the three experimental groups with full, half, and no lime application, pH increased significantly to 3.95, 4.46, and 5.89, respectively, while the maximum adsorption obtained from Langmuir adsorption curves, Qmax1 1553, Qmax2 2205, and Qmax3 3902 mg kg-1, respectively. While the maximum adsorption in the tea plantation areas varied between 1491 and 1514 mg kg-1, the maximum adsorption in hazelnut cultivation areas varied between 777 and 3333 mg kg-1. These findings suggest that liming or other methods to increase soil pH could be effective soil management in reducing Cu mobility in acidic soils.

The effect of soil moisture content and soil texture on fast in situ pH measurements with two types of robust ion-selective electrodes

Abstract. In situ soil pH measurements with ion-selective electrodes (ISEs) are receiving increasing attention in soil mapping for precision agriculture as they can avoid time-consuming sampling and off-site laboratory work. However, unlike the standard laboratory protocol, in situ pH measurements are carried out at lower and varying soil moisture contents (SMCs), which can have a pronounced effect on the sensor readings. In addition, as the contact with the soil during in situ measurements should be relatively short, effects of soil texture could be expected because texture controls the migration of protons to the electrode interface. This may be exacerbated by the fact that the electrodes used for in situ measurements are made of less sensitive but more robust materials as compared to the standard glass electrode. Therefore, the aim of the present study was to investigate the effect of soil moisture and soil texture on pH measurements using robust antimony and epoxy-body ISEs pressed directly into the soil for 30 s. The SMC was gradually increased from dry conditions to field capacity. A wide range of soil texture classes were included, with sand, silt, and clay contents ranging from 16 % to 91 %, 5 % to 44 %, and 4 % to 65 %, respectively. An exponential model was fitted to the data to quantify the relationship between SMC and pH. The results show that an increase in SMC causes a maximum increase in pH of approximately 1.5 pH units, regardless of the type of pH ISE used. Furthermore, for sandy soil textures, a rather linear relationship between pH and SMC was observed, whereas, with decreasing mean particle diameter (MPD), the model had a pronounced exponential shape, i.e., a greater pH increase at low SMC and a plateau effect at high SMC. With increasing SMC, the pH values asymptotically approached the standard pH measured with a glass electrode in 0.01 M CaCl2 (soil : solution ratio of 1:2.5). Thus, at high SMC, subsequent calibration of the sensor pH values to the standard pH value is negligible, which may be relevant for using the sensor pH data for lime requirement estimates. The pH measurement error decreases exponentially with increasing soil moisture and increases with decreasing MPD. Using a knee point detection, reliable pH values were obtained for SMC &gt; 11 %, irrespective of the pH ISE used. An analysis of the regression coefficients of the fitted exponential model showed that the maximum pH increase also depends on soil texture; i.e., the influence of soil moisture variation on the pH value increases with decreasing MPD. Moreover, the concavity of the exponential curve increases with decreasing MPD.

Effect of phosphorus management on yield and economics under direct seeded rice (Oryza sativa) and blackgram (Vigna mungo) intercropping in a rainfed acidic upland soil

A field experiment was conducted during rainy (kharif) season of 2019 at ICAR-National Rice Research Institute (NRRI), Central Rainfed Upland Rice Research Station (CRURRS), Hazaribagh, Jharkhand to study the effect of phosphorus management on productivity and profitability under direct seeded rice (Oryza sativa L.) (DSR) and blackgram [Vigna mungo (L.) Hepper] intercropping in rainfed acidic upland soil. The experiment was laid-out in a split-plot design comprised 4 methods of cropping, viz. Sole DSR; Sole blackgram; DSR + blackgram (4:1); and DSR + blackgram (4:2) allotted to main-plots and 4 phosphorus management practices, viz. P control (P0 ); Recommended dose of phosphorus (RDP) @17.5 kg P/ha; 50% RDP + phosphate solubilizing bacteria (PSB) @500 g/ha + arbuscular mycorrhiza fungi (AMF) @12.5 kg/ha; and 25% lime requirement (LR) + PSB + AMF in sub-plots. Experiment consisted of 16 treatment combinations, replicated thrice. The rice variety ‘Sahabhagi’ and blackgram variety ‘Uttara’ were used. Among the cropping systems, the highest grain yield was recorded in sole rice (3.84 t/ha) and sole blackgram (1.14 t/ha) which was significantly higher than yields under intercropping in both the ratios. Gross (`96,879/ha) and net returns (`70,603/ha) of sole blackgram were significantly higher than other cropping systems and followed by DSR + blackgram (4:2). Net benefit:cost (B:C) of sole blackgram was maximum (`2.69) and lowest in sole rice (`1.01). Among phosphorus management treatments, 50% RDP + PSB + AMF gave significantly higher net return (`49,440) and net benefit:cost (`1.68). Application of 100% RDP and 25% LR + PSB + AMF gave at par returns and net benefit:cost. It may be suggested that under rainfed uplands of eastern India, farmers may adopt either sole blackgram or intercropping of rice and blackgram in 4:2 over sole DSR for higher productivity and monetary returns. For better phosphorus management in soil they should inoculate PSB and AM fungi along with 50% RDP at the time of sowing.

Effect of training sample size, sampling design and prediction model on soil mapping with proximal sensing data for precision liming

Site-specific estimation of lime requirement requires high-resolution maps of soil organic carbon (SOC), clay and pH. These maps can be generated with digital soil mapping models fitted on covariates observed by proximal soil sensors. However, the quality of the derived maps depends on the applied methodology. We assessed the effects of (i) training sample size (5–100); (ii) sampling design (simple random sampling (SRS), conditioned Latin hypercube sampling (cLHS) and k-means sampling (KM)); and (iii) prediction model (multiple linear regression (MLR) and random forest (RF)) on the prediction performance for the above mentioned three soil properties. The case study is based on conditional geostatistical simulations using 250 soil samples from a 51 ha field in Eastern Germany. Lin’s concordance correlation coefficient (CCC) and root-mean-square error (RMSE) were used to evaluate model performances. Results show that with increasing training sample sizes, relative improvements of RMSE and CCC decreased exponentially. We found the lowest median RMSE values with 100 training observations i.e., 1.73%, 0.21% and 0.3 for clay, SOC and pH, respectively. However, already with a sample size of 10, models of moderate quality (CCC > 0.65) were obtained for all three soil properties. cLHS and KM performed significantly better than SRS. MLR showed lower median RMSE values than RF for SOC and pH for smaller sample sizes, but RF outperformed MLR if at least 25–30 or 75–100 soil samples were used for SOC or pH, respectively. For clay, the median RMSE was lower with RF, regardless of sample size.

Evaluation and Validation of Simple and Quick Methods of Lime Rate Determination under Acid Soil-Affected Areas of West Shewa Zone, Ethiopia

Liming acid soils is one of the available intervention options to amend soil acidity and increase crop production and productivity. The selection of a lime requirement determination easy and cheap method that is suitable to the soil conditions in a particular area is a pressing issue. Three lime requirement (LR) estimation methods i.e. (Exchangeable acidity, laboratory pH, and portable pH/Artikilee 3000) methods with one control treatment were tested in acid soils of the dhumuga learning watershed. A field study was conducted to verify the lime requirement (LR) by using portable pH methods and investigate the wheat response to lime. The treatments were laid out in an RCBD design with two farmers’ replications. The result showed that there a was significant (p&lt;0.05) yield response to the liming. The highest grain yield of 5512.3kg ha 1 was obtained from lime treated with the pH method statistically at par with Exchangeable acidity and article 3000 methods. LR rates estimated by the Exchangeable acidity method were lower than those estimated by laboratory pH and portable pH/ Artikilee 3000. However, both methods (laboratory pH and portable pH/ Artikilee 3000) overestimated the lime requirements of the study soil. The exchangeable acidity method was lower than the LR estimated with the article 3000 method by an average of 38 %, which indicates article 3000 methods overestimated the LR for the present study area, while exchangeable acidity methods were found to be reliable estimation LR. Lime rates determined with the three lime testing methods (pH method, Portable pH or Artikilee 3000 and exchangeable acidity) gave yield advantages of 31.94, 24.93 and 20.45%, respectively over the non-limed treatment. From the results of this study, it was concluded that the exchangeable acidity method gives a more reliable estimation of the lime requirements of acid soils of the study area.

Combining lime and organic amendments based on titratable alkalinity for efficient amelioration of acidic soils

Abstract. Ameliorating soil acidity using a combination of lime and organic amendments (OAs) can be an alternative to lime alone, but determining the appropriate OA rates can be difficult. We developed a new method for calculating the combined application rate of lime and OAs (wheat straw, faba bean straw, blended poultry litter, biochar, and compost) that is based on the titratable alkalinity of OAs and the equilibrium lime buffer capacity (LBCeq) of acidic soils. The effect of calculated soil amendment rates on soil pH was validated at soil water contents of 60 %, 100 %, and 150 % of field capacity (FC). The soil used to develop and validate the method was a sandy loam with a soil pH in deionised water (pHW) of 4.84 and a soil pH in 0.01 M CaCl2 solution (pHCa) of 4.21. The LBCeq of the soil was 1657 mg CaCO3 kg−1 pH−1 (where “CaCO3 kg−1 pH−1” denotes the amount of lime required to raise the pH of 1 kg of soil by one unit). The titratable alkalinity of the OAs ranged from 11.7 cmol Heq+ kg−1 for wheat straw to 357 cmol Heq+ kg−1 for compost. At 60 % FC, faba bean and wheat straw amendment increased the soil pHW to 6.48 and 6.42, respectively, but lower pH values were reached in soil amended with less biodegradable or resistant OAs (ROAs) (i.e. blended poultry litter, biochar, and compost). At 150 % FC, the two straws increased the soil pHW to only 5.93 and 5.75, respectively, possibly due to slower decomposition under submerged conditions, resulting in limited alkalinity production, whereas amendment with ROAs produced pHW values close to 6.5. With an increasing lime-equivalent value (LEV) of the OA, from 5.8 g CaCO3 kg−1 (wheat straw) to 179 g CaCO3 kg−1 (compost), the lime requirement to reach pHW 6.5 in lime–OA combinations decreased from 2.72 to 0.09 g CaCO3 kg−1. The developed method was shown to be effective in determining the appropriate rates of OAs (with or without additional lime) for the management of acidic sandy loam soils in this study and highlights the importance of the soil water content with respect to its acid-neutralising effect.

Effect of lime application on phosphorus adsorption and desorption in post-active acid sulfate soil, Thailand

The application of lime is the general method of improving acid sulfate soils. However, if a lot of lime is applied, it can reduce the bioavailability of nutrients in the soil, especially phosphorus. The objective of this study was to investigate the effects of liming at different rates on the availability, adsorption, and desorption of phosphorus in two post-active acid sulfate soils (Ay and Se). The experiment was performed in the laboratory. The experiment was laid out in a completely randomized design (CRD) with four treatments and three replicates, i.e., the application of lime at a rate of 0 (control), 0.5, 1.0, and 2.0 times the lime requirement (LR). The lime requirements of the soils in the Ay and Se were 5,690 and 12,250 kg CaCO3/ha, respectively. The finding revealed that increasing the amount of lime could increase soil pH, available phosphorus, and the phosphorus activation coefficient. Application of lime at a dosage of 1.0-2.0 LR resulted in the highest phosphorus adsorption maximum (Qm) (380 mg/kg), while 0.5 LR resulted in the lowest Qm (353 mg/kg) in Se soil only. As lime dosage increased, phosphorus desorption maximum (Dm) and phosphorus desorption ratio (Dr) increased, with 2.0 LR yielding the highest values (124 mg/kg and 23.6 percent for Ay soil, and 77.3 mg/kg and 20.3 percent for Se soil, respectively). The results suggested that applying lime according to the lime requirement test, especially 2.0 LR, is the best option to promote the release of phosphorus in post-active acid sulfate soils.

Investigating the accuracy and comparability of various lime prediction methods for Irish grassland mineral soils

AbstractSoil pH is a foundational element of agronomy, profoundly influencing biological, chemical and physical soil processes. Adjusting soil pH is a paramount factor for enhancing soil health and productivity with far‐reaching environmental benefits. Over time soil naturally tends towards acidity, a process expedited by intensive agriculture practices. To determine the extent of necessary pH corrections, precise soil pH testing is imperative. Various methods including buffer systems, titrations, lime incubations and algorithms considering soil texture are used to assess a soil's lime requirement and each method carries distinct advantages and disadvantages. The Shoemaker–McLean–Pratt (SMP) buffer method is extensively used in Ireland and internationally; however, safety concerns owing to the use of hazardous chemicals required within the method have been highlighted. This study investigates various soil lime requirement tests and compares their performance against a lime incubation study. A proposed alternative to the SMP buffer test for Irish grassland soils is also investigated. Analysis of results obtained indicates that the SMP buffer method demonstrated the highest r2 value of .497 when correlated with lime incubation results, while the calcium hydroxide titration method closely aligns with the SMP buffer method with an r2 value of .816, followed by the modified Mehlich buffer method with an r2 value of .763.

Environmental factors controlling biochar climate change mitigation potential in British Columbia's agricultural soils

AbstractTo combat climate change, carbon dioxide must be prevented from entering the atmosphere or even removed from it. Biochar is one potential practice to sequester carbon, but its climate change mitigation potential depends on a multitude of parameters. Differentiating areas of low and high climate change mitigation through biochar addition is key to maximize its potential and effectively use the available feedstock for its production. This study models the realistic application of 1 metric tonne (t) per hectare (ha) of forest harvest residue derived biochar over the climatically and pedologically diverse agricultural area of British Columbia, Canada, and provides a framework and assumptions for reproducibility in other parts of the world. The model accounts for the direct (input of organic carbon) and indirect (enhanced plant biomass) effects of biochar on soil organic carbon stock, its impact on nitrous oxide emissions from soils, and the avoided emissions from the reduced lime requirement due to biochar's alkalinization potential. Impacts are modelled over 20‐year time horizon to account for the duration and magnitude variation over time of biochar effect on plant biomass and nitrous oxide emissions from soil and conform to the IPCC GWP 20‐year time horizon reporting. The results show that a single application of 1 t of biochar per ha−1 can mitigate between 3 and 5 t CO2e ha−1 over a 20‐year time frame. Applied to the 746,000 ha of agricultural land of British Columbia this translate to the mitigation of a total of 2.5 million metric tonnes (Mt) CO2e over a 20‐year time frame. Further, the results identify agricultural areas in the Lower Mainland region (the southwestern corner of British Columbia) as the area maximizing climate change mitigation potential through biochar addition due to a combination of relative high temperature, high precipitation, and crops with high nitrogen requirement.

Spatial prediction of lime requirements by adjusting aluminium saturation in Sub-Saharan Africa croplands

Acidic soils cover over 30 % of Sub-Saharan Africa cropland. Acidic soils deprive crops of calcium, magnesium, potassium, molybdenum, and phosphorus due to aluminium (Al), manganese, and iron toxicities. Thus, liming is required to adjust the level of exchangeable Al3+ to the desired level of Al saturation of the crops grown. Lime requirement (LR) was quantified using soil dataset from Africa soil information service (AfSIS). Spatial variations of LR of cereals, pulses and cash crops were predicted using random forest algorithm. Our results revealed that mean of LR Mg CaCO3 (1 Mg = 106 g) ha−1 for cereal crops were 6.34, 6.35, and 4.41 for maize, sorghum, and upland rice, respectively. Mean of LR (Mg ha−1) for pulses were 6.28, 5.19, and 4.90 for common beans, soybeans, and cowpeas, respectively. Mean of LR Mg CaCO3 (1 Mg = 106 g) ha−1 for cash crops were 3.41 and 6.29 for coffee and cotton, respectively. Spatial variation showed that LR in croplands was higher in tropical humid regions than in semi-arid and arid regions and ranged from 0 to 8.8 Mg ha−1. The results of 10-fold cross validation for high model performance of LR for tested crops were coefficient of determination (R2) of 0.61, a root mean square error (RMSE) of 0.5, and a mean absolute error (MAE) of 0.31, maize LR with RMSE = 0.9, MAE = 0.24, and R2 = 0.51, and cotton LR with RMSE = 0.5, MAE = 0.31, and R2 = 0.60. We recommend predicting lime requirement in acidic soils of Sub-Saharan Africa by adjusting Al saturation up to the tolerance of the grown crop, updating soil surveys in Sab Saharan Africa, and using digital soil mapping to monitor soil acidity and lime requirement.

Generation of Lime Recommendation Maps Using Traditional Thematic Maps and Management Zones

ABSTRACT The uniform management used in conventional agriculture is not the most efficient strategy for managing agricultural areas. In this way, precision agriculture (PA), based on assessments of the variability of chemical, physical, and biological attributes, seeks to optimize the activities management by site-specific management of inputs, to increase profitability in the production system, and to minimize environmental impacts. In this context, this work aimed to compare two techniques to make traditional thematic maps (TTMs) and management zones (MZs) for site-specific lime application, using data from three commercial agricultural areas (Western Paraná State, Brazil) and three methods to calculate the lime requirement (LR): (1) neutralization of exchangeable aluminum (Al3+) (NEM), (2) increase of calcium (Ca2+) and magnesium (Mg2+) (KM), and (3) base saturation method (BSM). The LR was calculated on AgDataBox-Map (ADB-Map) web platform, using AgDataBox-Map-Aplic module (ADB-Map-Aplic). ADB-Map is an application of the web platform, which aims at integrating data, software, procedures, and methodologies for Digital Agriculture. The Variance Reduction (VR%), Fuzziness Performance Index (FPI), Modified Partition Entropy (MPE), Improved Cluster Validation Index (ICVI), Smoothness Index (SI%) and Fragmentation index (FI%) indices were used to assess MZs quality, and the Kappa and global accuracy indices compared the agreement between TTMs and MZs. The results showed that the BSM method presented the best results in LR and distribution. According to the indices, MZs delineated with two classes generally (45 of the 47) showed the best results. MZs with application rates in each class calculated by the median of the lime quantities provided the lowest total LR per area. Thus, the MZs delineation allows applying lime more efficiently, reducing production costs, and allowing more sustainable use of inputs.

Effect of rice-establishment methods and nutrient management on productivity, profitability and soil health under rice (Oryza sativa)–groundnut (Arachis hypogaea) cropping system

A field experiment was conducted during the rainy (kharif) and winter (rabi) seasons of 2019–20 and 2020–21 at the Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, to study the effect of different riceestablishment methods and nutrient management on yield, economics and soil properties in rice (Oryza sativa L.)– groundnut (Arachis hypogaea L.) cropping system. The experiment was laid out in a split-plot design with 3 replications. Six treatment combinations, comprising of 2 rice-establishment methods, viz. direct-seeded rice (DSR) and transplanted rice (TPR) and 3 levels of nutrient-management practices, viz. inorganic-100% soil test-based fertilizers (STBF), organic-dhaincha [Sesbania aculeata (Wild.) Pers.] green manuring +1/3rd soil test-based nitrogen (STBN) through vermicompost @2 t/ha + 1/3rd STBN through neem oil-cake @ 0.87 t/ha and integrated nutrient management (INM), viz. green-manuring + 50% STBN (inorganic @ 50.0 kg N/ha) + 100% P2 O5 + 100% K2 O, in rice during kharif were allotted to the main-plots. Three nutrient-management practices to groundnut during rabi, viz. 75% STBF, 100% STBF and 75% STBN (inorganic) + 25% STBN through FYM @ 1.63 t/ha + 0.2 lime requirement @ 0.38 t lime/ha + biofertilizers (Rhizobium + phosphate-solubilizing bacteria) + 100% P2 O5 + 100% K2 O, were allotted to the sub-plots. Transplanting of rice (TPR) increased the yield parameters of rice, resulting in 3.3% higher grain yield (5.65 t/ha) than direct seeding of rice. The INM improved the yield parameters of rice, resulting in 13.3 and 15.2% increase in grain yield over sole inorganic and organic practice, respectively. Carryover effect of the DSR on succeeding groundnut crop improved the yield attributes and resulted in 15.8% higher pod yield (2.49 t/ha) than the groundnut crop grown after TPR. Residual effect of organic nutrient management in rice crop enhanced the yield parameters of succeeding groundnut, resulting in 4.2 and 16.5% higher pod yield than the groundnut grown after INM and inorganic practice in rice, respectively. The INM practice in groundnut increased its yield parameters, resulting in 11.4 and 18.1% higher pod yield over 100% and 75% STBF, respectively. The DSR enhanced the system yield (12.51 t REY/ha) of rice-groundnut cropping system by 6.8% over TPR. The INM practice in rice crop enhanced system yield by 12.6 and 4.2% over inorganic and organic practice, respectively. Similarly, INM to groundnut crop resulted in 7.4 and 11.2% higher system yield than 100% and 75% STBF, respectively. The DSR, INM practice in rice and INM practice in groundnut crop fetched higher gross returns (`240.4 ×103 /ha, 245.5 ×103 /ha and 247.0 ×103 /ha), net returns (`97.2 ×103 /ha, 108.9 ×103 /ha and 92.7 ×103 /ha), benefit: cost ratio (1.71, 1.80 and 1.62) and system profitability (`207.9, 298.5 and 254.1/ha/day). Organic management under DSR and INM in groundnut improved the physico-chemical and biological properties of soil.

Point of Zero Charge of Soils - It’s Dynamics under Fertilizer Management Practices and Nutrient Availability

Aims: To study the dynamics of point of zero charge of different soil types and determine the availability of nutrients under the influence of specific fertilizer management practices.&#x0D; Study Design: Completely Randomized Design.&#x0D; Place and Duration of Study: Department of Soil Science, Assam Agricultural University, Jorhat, Assam; between March 2020 and December 2021.&#x0D; Methodology: We estimated the point of zero charge (PZC) components, i.e., the point of zero salt effect (PZSE) and point of zero net charge (PZNC) in six surface soil samples [black soil (Vertisol), laterite soil (Alfisol), red soil (Alfisol) of Odisha, and alluvial soils belonging to Entisol, Inceptisol, and Alfisol of Assam, India] through potentiometric titration and ion retention methods respectively. The soils were subjected to four specific fertilizer management practices under laboratory incubation, viz., FYM @ 5 t ha-1 (T1), NPK @ 80:40:40 for Odisha soils and 60:20:40 for Assam soils (T2), T1 + T2 (T3) and T3 + Lime requirement/ Gypsum requirement (T4). The PZC components and availability of nutrients were determined at 15 and 30 days after incubation.&#x0D; Results: The PZSE values of the soils ranged from 2.18 to 4.70, while PZNC values were achieved at relatively lower pH ranging from 2.03 to 4.10. Highest values of PZSE and PZNC were recorded under treatment T2 followed by T3, T4 and T1 for all the incubated soil samples, however there was a decrease in the PZC values with increase in days of incubation. Comparatively, the treatment T4 resulted as the most ideal fertilizer management practice. Besides providing optimum amount of primary and maximum amount of secondary nutrients, T4 regulated the PZC values favouring minimal loss of nutrients and enhanced nutrient use efficiency. The availability of nutrient ions is influenced by the difference between soil solution pH and PZC values of the soil, which recorded to be highest for Vertisol (OS1), followed by Entisol (AS1), Inceptisol (AS2), and Alfisol (AS3, OS2, OS3) soil orders.&#x0D; Conclusion: The exchange and availability of cationic nutrients get enhanced due to higher CEC in soils with high clay and organic matter percentage. The pH of these soils must therefore be regulated for better availability of anionic nutrients. Highly weathered soil of Alfisol order exhibit optimal CEC over a narrow pH range, favouring better availability of anionic nutrients and hence simultaneously require frequent fertilizer application along with organic manures for the enhanced retention, mobility and availability of nutrients in soil.

Determination of Lime Requirement with Compost on Acidic Ultisols for Wheat Crop in the Gurage Zone of Ethiopia

Acidic soil adversely affects the plant growth and production. Various ameliorating strategies are known, but the optimum rate of lime and compost rate determination for better nutrient management and production in acid Ultisols was not well studied, so the main objective of this study was to determine optimum lime and compost rate for wheat production. A pot experiment was performed on the soil collected from Yefereze (Cheha District). The incubation trail was conducted in factorial combination of four level lime (8.44, 6.33, 4.22, and 0 t·ha−1) and compost (15, 10, 5, and 0 t·ha−1). The sixteen treatments were arranged in completed randomized design (CRD) with triplicate replications in the greenhouse. After 75 days, each pot that was planted with wheat and crop performance had been monitored. The textural class of the soils of the experiment was clay with strongly acidic pH. The organic carbon (2.17%) and total nitrogen content (0.17%) status was medium. The available phosphorus (Av. P) contents were very low (1.63 ppm). The experimental study result revealed that all the three rates of lime and compost continuously improve the soil pH throughout the study periods and the maximum soil pH (6.53) was obtained in combination of 8.44 t·ha−1 and 10 t·ha−1 lime and compost, respectively. The compost amended treatment indicated slight improvement in soil reaction which assert that using compost alone did not reduce soil acidity within 75-day periods in strongly acidic soil condition for suitable wheat production. Liming alone or integrated application increases soil pH (4.69 to 6.53), cation exchangeable capacity (CEC) (27.18 to 31.58 cmolckg−1), exchangeable calcium (3.56 to 8.43 cmolckg−1), available phosphorus (Av.P) (1.63 to 5.27 ppm), total nitrogen (TN) (0.19 to 0.24 ppm), and exchangeable acidity reduced (0.73 cmolckg−1 to trace). Integrated application of 8.44 and 5 t·ha−1 lime and compost rates improve the overall soil property and maximize the wheat yield by 24.26%. Generally, the limiting factor for wheat production of the study area was the acidity of the soil. The combined application of lime and compost raised the pH and improved the suitability of the soil for wheat production. However, the status of Av. P was low after the amendment, and it is advisable to integrate phosphorus containing fertilizer in addition to lime and compost for optimum and sustainable production of wheat in the study area. Since the incubation and greenhouse experiment were conducted in a controlled environment, there is a need for field verification. It is also advisable to assess the economic feasibility of the different rates of lime and compost for an appropriate soil management decision.

Integrating Soil pH, Clay, and Neutralizing Value of Lime into a New Lime Requirement Model for Acidic Soils in China

Modelling the lime requirement (LR) is a fast and efficient way to determine the amount of lime required to obtain a pH that can overcome the adverse effects caused by soil acidification. This study aimed to model the LR based on the properties of soil and lime. A total of 17 acidic soils and 39 lime samples underwent soil–lime incubation in the laboratory. The predictive equations for the LR (t ha−1) were modelled using ∆pH (the difference between the target pH and initial pH), the neutralizing value (NV, mmol kg−1) of lime, soil pH, soil clay content (%), soil bulk density (BD, g cm−3), and the depth of soil (h, cm) as the factors in an exponential equation. The generic predictive equation, LR=∆pH×e−3.88−0.069×NV+0.51×pH+0.025×Clay×BD×h, was validated as the most reliable model under field conditions. Simplified predictive equations for different soil textures when limed with quicklime and limestone are also provided. Furthermore, the LR proportions provided by hydrated lime, quicklime, limestone, and dolomite in commercially available lime can be expressed as 0.58:0.64:0.97:1.00. This study provides a novel and robust model for predicting the amount of lime product containing components with different neutralizing abilities that are required to neutralize soils with a wide range of properties. It is of great significance to agronomic activities and soil remediation projects.

Effect of application of lime with vermicompost on the activities of microorganisms of some acidic soils of West Bengal

Aim: To evaluate the efficacy of integrated application of lime at partial doses of lime requirement (LR) with vermicompost in acid soils to minimize the soil acidity, improve the population of beneficial microorganisms and their microbial activities in comparison to sole treatment of lime as per Lime Requirement dose. Methodology: Two highly acidic soils collected from the farmer’s field of South 24 Parganas district, West Bengal having no history of acidity management were used. The soils were treated with different rates of lime requirement (LR, ⅔LR &amp; ½LR) and lime (½LR) + vermicompost (5 tha-1) treatments and incubated for 60 days. Soil pH, soil organic carbon content, different microbial populations, microbial respiration and enzymatic activities (FDHA and DHA) were assessed at different days. Results: The study indicated that the lime treatments showed rapid increase in soil pH towards the slightly alkaline condition whereas lime +vermicompost treatment (T5) successfully maintained the neutralized condition. Integrated treatment of lower doses of lime and vermicompost (T5) was found to efficiently promote the microbial population (rhizobium, phosphate and potassium solubilizing bacteria) and microbial respiration (basal and substrate induced respiration) activity, which might be attributed to the improvement soil microbial status. FDHA and DHA increased significantly with ‘lime’ as well as the ‘lime with vermicompost’ treatments in comparison to control. Interpretation: The incorporation of lower amount of lime and organic matter efficiently neutralizes the acidity and boosted up the microbial activities simultaneously that in turn might improve the soil health. The high cost to purchase the huge quantity of lime as recommended LR (9.25 tha-1) for studied soils turns the farmers uninterested to follow lime practice and interrupted the mitigation of soil acidity. Thus, the study might conclude that the integrated approach of lime application@½LR with vermicompost might successfully ameliorate the acid soils in terms of acidity as well as the soil microbial activities. Key words: Acid soil, BSR, Dehydrogenase, Fluorescein diacetate, SIR, Lime, Vermicompost

Effects of Liming on Acid Ferrasols for Sustainable Crop Production in Uganda – A Review

Ferralsols are the predominant soil type covering about 70% of the total land area of Uganda; they are mostly found in the Central and Western regions of the country. Ferralsols are highly weathered, acidic and have inherently low nutrient reserves. Degradation of these soils has led to reduced agricultural production and productivity. Despite the increased human population and the importance of Agriculture to the majority of the households in Uganda, little or no research has been carried out on Acid Ferralsols to improve food security and sustain livelihoods. Besides, the country’s research programs have not prioritized the use and management of soil fertility management strategies such as liming. Crop yields on these soils are often far less than those on research stations. This review paper focuses on the extent and effects, causes, challenges and opportunities associated with liming Acid Ferralsols and the effects on soil properties and crop yield. Many studies have shown that detrimental effects of acid soils can be ameliorated through liming, thus improving on the physio-chemical properties to improve crop production and yield. More research is anticipated to develop lime requirements for acid Ferralsols so as to meet the growing food demand in Uganda.

Calculating soil titratable acidity from routine soil analyses of cultivated South African soils using various model structures

Soil titratable acidity (TA) is determined through extraction with an acetate-buffered salt solution (potassium sulphate, K2SO4) and is routinely used to predict the soil lime requirement using the Eksteen method. Soil TA is not always reported by commercial soil testing laboratories, but rather exchangeable acidity (1M KCl) is determined. Therefore, a need exists to use other routinely determined soil properties in a model to derive TA. In this study, routine soil-analysis results from a commercial laboratory (n = 5 915 measurements) were used to generate various model structures to calculate a theoretical value of TA and to evaluate the accuracy thereof. Measured TA was found to be significantly correlated to the calculated TA using the Eksteen R-value, soil pH, organic carbon percentage, exchangeable Ca2+ and Mg2+, and a function of the interaction between pH and organic carbon. Soil TA could be calculated most accurately using these factors in multivariate adaptive regression splines model (r 2 = 0.69, mean absolute error = 0.16) at TA values of < 2 cmolc kg−1. However, the exponential model calculations remained stable over a larger range of actual TA values up to 4 cmolc kg−1. Given the ease of use and interpretability, it is recommended that an exponential function model is used to calculate TA.

Using a single base addition for lime requirement of Acrisols: a case study in Southeastern Vietnam

ABSTRACT Developing lime requirement (LR) methods for routine use is one of the key tasks for agronomists because such methods would provide accurate lime recommendations while saving time, labour, and cost. This paper examined the effects of testing conditions to LR and tested if a single base addition can be routinely used for LR estimates. With Acrisols from Southeastern Vietnam (0–30 cm), results showed that lime rates, equilibrium times, and shaking had great effects on LR. A lime rate [as saturated Ca(OH)2] of 0.10 × 10−3 kg CaCO3 kg soil−1 in 1:1 soil:0.01 M CaCl2, a 90-min equilibrium, and continuous shaking are the optimum conditions for LR estimates. Titration with a single base addition using the optimum conditions estimated 85.8% of LR by the reference method. The estimation rate can be as high as 97% if more prediction errors were ignored in low LR soils. Although prediction errors are likely, titration with a single base addition can be suitable for routine use on Acrisols in Southeastern Vietnam, with further testing, adjustment, and validation.