Lime Requirement Research Articles

Estimating lime requirements for tropical soils: Model comparison and development

Acid tropical soils may become more productive when treated with agricultural lime, but optimal lime rates have yet to be determined in many tropical regions. In these regions, lime rates can be estimated with lime requirement models based on widely available soil data. We reviewed seven of these models and introduced a new model (LiTAS). We evaluated the models’ ability to predict the amount of lime needed to reach a target change in soil chemical properties with data from four soil incubation studies covering 31 soil types. Two foundational models, one targeting acidity saturation and the other targeting base saturation, were more accurate than the five models that were derived from them, while the LiTAS model was the most accurate. The models were used to estimate lime requirements for 303 African soil samples. We found large differences in the estimated lime rates depending on the target soil chemical property of the model. Therefore, an important first step in formulating liming recommendations is to clearly identify the soil property of interest and the target value that needs to be reached. While the LiTAS model can be useful for strategic research, more information on acidity-related problems other than aluminum toxicity is needed to comprehensively assess the benefits of liming.

Lime and Vermicompost Application to Acid Soils and Their Effects on Maize Yield and Yield Components in Lalo Asabi District, West Wollega Zone, Oromia, Ethiopia

Soil acidity is one of the major yield-limiting factors for crop production worldwide, particularly on highly weathered and leached tropical soils. Different reports have indicated that there is significant soil acidity coverage in Ethiopia. In particularly, in the western part of the country, soil acidity is a well-known problem limiting crop production and productivity. As part of the solution to such a problem in soils, the combined application of lime and VC on maize has not been investigated in the area, in which maize was one of the potential cereal crops in the area. A field experiment was conducted at Lalo Asabi district in western Wollega during the 2020 cropping season to evaluate the responses of maize to the combined application of lime and vermicompost (VC). The experimental treatments were five rates of lime (CaCO3) (0, 25, 50, 75, and 100% of lime requirement (LR)) and three levels of vermicompost (0, 2.5, and 5 t ha-1). The treatments were arranged in factorial combinations in a randomized complete block design with three replications. One composite surface soil samples from a depth of (0-15 cm) was collected from the experimental field before the commencement of the experiment. Maize yield and yield components were measured following standard procedures. The yield components and yield results revealed the main effects of lime and VC showed a significant effect (p<0.05) on the number of days to 50% tasseling and silking, ear height, number of cobs per plant, number of grains per cob, thousand grain weight, above ground biomass, and harvest index of maize. However, days to 90% physiological maturity, plant height, cob length and grain yield of maize were significantly affected (p<0.05) by lime and VC interactions. Even though both were statistically equal, the combined application of lime at 100% LR + 5 t VC ha-1 yielded the highest grain yield (7.99 t ha-1) followed by the combined application of lime at 75% LR + 2.5 t VC ha-1 whereas the lowest grain yield (2.97 t ha-1) from control plots. The results of economic analysis indicated that the combination of lime at 75% LR + 2.5 t VC ha-1 showed a marginal rate of return of 2322.74%, with the highest net benefit of 49980 Ethiopian Birr compared to other treatments. This study indicates combined use of lime and VC could ameliorate the adverse effect of soil acidity, and application of 75% LR + 2.5 t VC ha1 enhances grain yield and produces the highest net benefit of maize grown on acidic soil of the Lalo Asabi district.

Dynamics of Acidity Component of the Soils as Influenced by Liming in Upper Brahmaputra Valley Zone of Assam, India

An incubation study was conducted to investigate the effect of lime (CaCO3 )on the acidity components in Upper Brahmaputra Valley Zone (UBVZ) of Assam. Fourteen(14) geo-referenced soil samples were collected from Sibsagar and Jorhat districts of Assam. Soils were treated with 3 different doses of lime viz. 10 per cent Lime Requirement (LR10), 25 per cent Lime Requirement (LR25) and 50 per cent of Lime Requirement (LR50) and initial properties were recorded before liming. Samples were incubated in laboratory at different period of time viz. 15, 30, 60 and 90 days after liming (DAL) with moisture content at Field Capacity (0.33 bar). At four different intervals, soils were analysed for soil acidity components viz. total acidity, exchange acidity, exchangeable Al3+ and exchangeable H+. The soil of Upper Brahmaputra Valley Zone (UBVZ) of Assam were highly acidic to moderately acidic, sandy loam to silt loam in texture with high OC content ranged from 0.72 to 2.59%. The Cation Exchange Capacity (CEC) value ranged from 7.8 to 14.2 cmol (p+)/ kg. Application of lime brought about mark decreased in acidity components viz. total acidity, exchange acidity, exchangeable aluminium and exchangeable hydrogen. Soil acidity components recorded highest decreased at 90 DAL @ LR50 and decreased started from 15 days onwards. The findings of the investigation showed that liming @ LR10 was found effective in reducing soil acidity. The residual effect of lime was found persisting till 90 days. However, the magnitude of lime was increasing with increase in application of lime@ from LR10 to LR25 and to LR50.

Forms of acidity and lime requirement of vindhyan soils in eastern Uttar Pradesh

Forms of acidity and lime requirement of vindhyan soils in eastern Uttar Pradesh

Effect of application of graded levels of lime requirement on the availability of phosphorus and sulphur in acidic soils of vindhyan region

Effect of application of graded levels of lime requirement on the availability of phosphorus and sulphur in acidic soils of vindhyan region

Lime requirement for agricultural soils: A review of the current and potential methods for routine use

AbstractLiming is one of the key agronomic practices to improve crop yields in acid soils because, among other things, it reduces aluminum toxicity and creates favorable conditions for crop growth. For an effective liming program, the methods to determine lime requirement should be as precise as possible. This paper reviews the existing lime requirement methods and discusses the potential of a new one suitable for routine use in the laboratory to test most agricultural soils. The most widely used lime requirement methods can be categorized into four groups: titration, incubation, buffer, and field methods. Other methods such as spectroscopy method or the use of empirical equations have also been adopted. Although some methods are highly reliable, they are not optimal for routine use because they are inconvenient during the laboratory procedures or cannot be validated for all conditions. Based on the linearity between soil pH and the added base in the pH range from 4.5–6.5 in most agricultural soils, a titration‐based method on 1:1 soil:0.01 M CaCl2 slurry of a single sample appears to be a promising candidate for routine use. In further studies, this generally applicable method should be evaluated to provide a better comparison to established methods for lime requirement determination.

Buffer capacity as a method to estimate the dose of liming in acid soils

Objective: The study proposes using the dolomite buffer capacity (BCDolomite) as a method of estimating the lime requirement in soils that agronomically require a pH increase. Design/methodology/approach: In six soil samples with different levels of response to the application of dolomite, the organic matter (OM), the content of sand, silt and clay, pH, K, Ca, Mg and the potential acidity (Al+H) were determined. Assuming an apparent density of 1000 kg/m3 and a volume per hectare of 2000 m3, the soils were placed in polyethylene containers and treated with dolomite in doses equivalent to 0, 750, 1500, 2250 and 3000 kg/ha, establishing the BCDolomite as the inverse of the slope resulting from the relationship between the pH and the dose of dolomite. Results: In soils with low response to the dolomite, the content of clay and OM was 280 and 26 g/kg, respectively, and in high response soils, the content of clay and OM was 240 and 47 g/kg, respectively. In all cases, a simple and direct linear relationship was observed (R2 > 0.85; p < 0.05) in the relationship between pH and dose of dolomite. Limitations on study/implications: The results obtained under controlled conditions show that BCDolomite constitutes a viable method to estimate the lime requirement. Findings/conclusions: The BCDolomite showed sensitivity to the complexity of the clay fraction and to the organic matter in the soil, for which the dolomite requirement is equal to the product of the desired pH increase and the BCDolomite

Methods to Recommend Corrective Measures for Agricultural Soils: A Systematic Literature Study

ABSTRACT Acid soils cover about 30% of the total ice-free land area. Based on this, the study aimed to evaluate soil acidity correction, focusing on identifying studies on limestone recommendations and corrective measures in agricultural systems. To do so, a systematic literature review (SLR) was carried out, composed of: 1) a systematic literature mapping (SLM), which identifies studies using topic-specific keywords and database automatic search; 2) Snowballing, technique that expands the initial selection using references of the selected studies; and 3) a SLR to synthesize the selected papers. First, 169 scientific papers were selected, of which 116 by SLM, 26 by backward Snowballing, and 27 by forward Snowballing. Most of the papers were about lime requirement (LR) methods (43%) and liming effects on soil and plants (19%). A total of 26 LR methods were found in the papers, of which most were base saturation and Shoemaker-McLean-Pratt methods. Calcium and magnesium carbonates, as well as dolomite, were the main sources of soil acidity correction. In brief, the study provided a critical and constructive analysis of the existing literature on soil acidity correction; the findings showed that liming is the most used and effective method to neutralize soil acidity.

Liming guidelines for soils under wheat cropping in the eastern Free State, South Africa

Soil acidity hampers the sustainability of wheat production in the eastern Free State, South Africa. Specific guidelines for liming are needed by farmers and advisors to ameliorate this condition. In this study, soils from four representative wheat producing farms were used for incubation and field studies to generate data for the development of liming guidelines. The clay content of the soils ranged between 8 and 33%, with pH (KCl) values below 4.5 and percentage acid saturation (%AS) above 8. These parameters are regarded as thresholds for wheat cultivation. Liming of the topsoil (0–200 mm) at different rates increased pH (KCl) linearly and decreased %AS exponentially. Either the resulting pH (KCl) or %AS values can be used in the development of liming guidelines. Using these values, an equation was established that is suitable for the estimation of lime requirement of soil: y 8.320× 1 + 0.0459× 2 − 1.0370, R 2 = 0.86 where y is the lime requirement (tonnes ha−1), x 1 = ΔpH (KCl) and x 2 = clay content (%). This equation was also used to compile a look-up table from which the soils’ lime requirement can be derived. Farmers and advisors can improve liming strategies for wheat production by applying this information.

Evaluation of nonhazardous lime requirement estimation methods for Oregon soils

AbstractThe Shoemaker, McLean, and Pratt (SMP) buffer pH method has been used historically in Oregon for estimating lime requirement, however concerns regarding hazardous waste disposal have caused increased interest in nonhazardous methods. The objective was to compare nonhazardous lime requirement estimate (LRE) methods to the SMP method for predicting incubation lime requirement (LRi) for Oregon soils. Twenty‐four soils (pH ≤ 5.5) were incubated with seven rates of CaCO3 ranging from 0 to 22.4 Mg ha–1 and incubated for 90 d at 19 °C. Seven different LRE methods were evaluated and regressed against LRi for pH targets of 5.6, 6.0, and 6.4 using linear regression. The Sikora (r2 = .91–.93), modified Mehlich (r2 = .87–.90), and Sikora‐2 (r2 = .82–.93) buffer methods showed potential as alternatives to SMP (r2 = .91–.93) based on accuracy. A multilinear model combining clay content, KCl‐extractable Al, soil organic matter (SOM), extractable Mg, and pH1:2 also effectively predicted LRi (R2 = .97). The Moore–Sikora method (r2 = .89–.93) showed precision issues due to high replication variability. The single addition of Ca(OH)2 method (r2 = .67–.74) was less accurate than other evaluated methods. In conclusion, there were several viable non‐hazardous LRE method alternatives to the SMP buffer method for Oregon soils, based on accuracy and precision.

Utility of visible and near-infrared spectroscopy to predict base neutralizing capacity and lime requirement of quaternary soils

Detailed knowledge of a soil’s lime requirement (LR) is a prerequisite for a demand-based lime fertilization to achieve the optimum soil pH and thus sustainably increasing soil fertility and crop yields. LR can be directly determined by the base neutralizing capacity (BNC) obtained by soil-base titration. For a site-specific soil acidity management, detailed information on the within-field variation of BNC is required. However, soil-base titrations for BNC determination are too laborious to be extensively applied in routine soil testing. In contrast, visible and near-infrared spectroscopy (visNIRS) is a time and cost-effective alternative that can analyze several soil characteristics within a single spectrum. VisNIRS was tested in the laboratory on 170 air-dried and sieved soil samples of nine agricultural fields of a quaternary landscape in North-east Germany predicting the soil’s BNC and the corresponding lime requirement (LRBNC) at a target pH of 6.5. Seven spectral pre-processing methods were tested including a new technique based on normalized differences (ND). Furthermore, six multivariate regression methods were conducted including a new method combining a forward stagewise subset selection algorithm with PLSR (FS-PLSR). The models were validated using an independent sample set. The best regression model for most target variables was FS-PLSR combined with the second Savitzky-Golay derivation as pre-processing method achieving R2s from 0.68 to 0.82. Finally, the performance of the direct prediction of LRBNC (R2 = 0.68) was compared with an indirect prediction that was calculated by the predicted BNC parameters. This resulted in slightly higher correlation coefficients for the indirect method with R2 = 0.75.

Effect of dolomite and calcite on growth, yield and economics of rice in strongly acidic soils of Kanyakumari district

Soil acidity is an important agricultural problem while evaluating the production potential of most of the crops. A field experiment was conducted in farmers field at Gananadhasapuram village of Thovalai taluk, Kanyakumari district during Pishanam (Oct-Feb) season of 2017-2018. To utilize the calcite and dolomite in different levels along with RDF + ZnSO4 with ten treatments based on Lime requirement and replicated thrice in RBD design. The results revealed that significantly highest plant height (100 cm), number of tillers m-2 (411), number of productive tillers m-2 (375), thousand grain weight (26.6 g), grain (7.09 t ha-1) and straw (10.3 t ha-1) yield of rice were recorded with the application of dolomite @ 0.75 LR (6.36 t ha-1) along with RDF + ZnSO4 (T7) compared to other treatments. The economic analysis demonstrates that dolomite @ 0.75 LR (6.36 t ha-1) along with RDF + ZnSO4 treatment produced higher gross returns (INR 116662 ha-1), net returns (INR 54018 ha-1) and B: C (1.86) ratio than all other treatments. The study clearly indicated that in strongly acidic soils, the treatment T7 is found to be the best for getting higher yield and higher returns per rupee invested under rice cultivation during Pishanam season.

Soil Acidity Indicators for Liming in Tropical Acid Soils Cropped With Soybean Under Short- and Long-Term No-Tillage Systems

Although the movement of liming materials under no-tillage (NT) systems can intensify stratification of soil chemical properties and be deleterious to soybean growth, little is known regarding the soil acidity indicators used to predict lime requirement (LR) in Brazilian soils under NT. Thus, we hypothesize that the recommendation criteria used for predicting LR in soils under NT must be different from those adopted in soils under conventional tillage (CT), and the reference values for such liming indicators may vary according to the phase following the adoption of the NT system. The study aimed to obtain soil acidity indicators for soybean (Glycine max (L.) Merill) in tropical acid soils under no-tillage (NT) systems and their respective critical levels according to the phase of NT. Sites under NT were commercial soybean crop areas located in the Cerrado region, Brazil. Systems analyzed were NTI (NT management from 0 to 5 years—initial phase), and NTTC (NT management from 5 to 20 years—transition-consolidation phase). Soil samples were collected at the 0-5, 0-10, and 0-20 cm layers, and analyzed for chemical characteristics. Relationships between crop yield response of soybean to lime application and various soil acidity-related characteristics led to establishing soil acidiy indicators for liming in tropical acid soils under no tillage. Critical levels were approximately similar in both phases of NT for exchangeable Ca and Mg, and potential acidity, but varied greatly depending on the soil layer and phase of NT management for soil pHCaCl2, CECpH7.0, and base saturation. In general, for both phases of NT, the critical levels of soil acidity indicators were lowest for the 0-20 cm layer, moderate for the 0-10 cm layer, and highest for the 0-5 cm layer. Lime applied with incorporation in the NTTC phase kept the soil with chemical attributes more favorable for plant growth than when surface liming was employed in the NTI phase, which was verified by the soybean yield response. Our results indicate the differences on the soil acidity indexes between the top and bottom depths that would not have been realized in a soil sampling for conventional tillage. Hence, recommendation criteria for lime application considering distinct soil depths and NT systems will be helpful when making lime decisions. Further research should focus on the development of reliable methods for predicting LR according to the NT phase and consequently maximize soybean production under NT systems in Brazil.

Application of phosphate solubilizing fungi and lime altered the soil inorganic phosphorus fractions in an Ultisol of north-eastern India

ABSTRACT The gradually dwindling reserves of rock phosphate, the primary material used in the manufacturing of phosphatic fertilizers, encourages researchers to look for ways to exploit the accumulated fixed P pool in soil. Phosphate solubilizing microorganisms (PSM) could be a viable option for addressing the problem at a lower cost. Keeping these in mind, the present study was undertaken to evaluate the changes in the distribution of P in soil as affected by P fertilization, phosphate solubilizing fungi (PSF) and liming vis-à-vis the contribution of these fractions toward P nutrition of a test crop soybean (Glycine max L.). A bulk surface soil sample (0–15 cm) was obtained from Negheriting tea estate of Golaghat district of Assam, India (Ultisol, pH = 4.23) and after processing, three levels of P [0, 50, and 100% of recommended dose of P (RDP)], two levels of lime [No lime, 1/10th of Lime Requirement (LR)] and two levels of PSF (No-PSF, PSF) were applied in a completely randomized design with three replications. Sequential P fractionation was done in the post-harvest soil. On an average, the abundance of different P fractions in the soil, expressed as % of total P, followed the order: residual P (67.5%)> Fe bound P (12.1%)> reductant soluble P (8.85%)> Al bound P (4.04%)> occluded P (3.79%)> Ca bound P (3.11%)> soluble and loosely bound P (0.46%). All the inorganic P fractions except the residual P, increased significantly with P fertilization. Either liming or PSF application significantly increased the soluble and loosely bound P fraction and decreased the Al bound and Fe bound P fractions in soil. Positive growth response of soybean was obtained due to the application of P, lime, and PSF. Liming increased the P uptake by 30.4% and dry matter yield of soybean by 18.5% over no liming. On the other hand, PSF inoculation increased the P uptake by 16.7% and dry matter yield by 7.77% over no inoculation. So, it is evident that in short term, either liming or PSF was able to solubilize the native soil P. Phosphorus×lime and lime×PSF interactions should also be exploited in future endeavors.

Residual Effect of Lime Rate after Five Years and P Fertilizer Rates on Bread Wheat (Triticum Aestivum L.) Yield on Acidic Soil in Banja District, North Western Ethiopia

Soil acidity problem is one of the bottlenecks to improve crop production in high rainfall regions of Ethiopia in general and in Banja district particular. This study aimed to determine the residual effect of lime and P fertilizer on the acid properties of soils and to develop models whereby the change in acidity indicators of soils can be predicted as a result of lime application. The experiment was laid out in a randomized complete block design with three replications. Five levels of lime (0, 1.15, 2.3, 3.45, 4.6 t ha-1) and four levels of Phosphorous (0, 10, 20, and 30 kg ha-1) were combined in a complete factorial arrangement. The study was conducted for three consecutive years from 2015 to 2017 main cropping seasons at Banja district. Mean grain yield and yield components as affected by different levels of lime and phosphorus fertilizer. Analysis of variance showed that all limed treatments were higher mean values of grain yield and yield components relative to control plot (no lime and P) in all over combined cropping years. Moreover, over year combined mean the highest grain yields (1115.9 kg ha-1), biomass yields (3591.2 kg ha-1), number of seeds per plant (21.54), plant height (64.50 cm) and spike length (5.24 cm) were recorded under 4.6 t ha-1 of lime application of plot. The lowest grain and biomass yields were recorded in control plots. However, over year mean 4.6 t ha-1 of lime application plot the grain yield and biomass yield of wheat were increased by (151.1%) and (123.3%) related to the control plot, respectively. Hence, lime application at the rate of 3.45 t ha-1 (150% of the lime requirement of the soils based on its exchangeable acidity) coupled with 20 kg ha-1 P fertilizer could serve as a reference to boosting wheat production in the study area and similar areas with possible re-liming of the soils in every five years.

Residual Effect of Lime Rate after Five Years and P Fertilizer Rates on Bread Wheat (Triticum Aestivum L.) Yield on Acidic Soil in Banja District, North Western Ethiopia

Soil acidity problem is one of the bottlenecks to improve crop production in high rainfall regions of Ethiopia in general and in Banja district particular. This study aimed to determine the residual effect of lime and P fertilizer on the acid properties of soils and to develop models whereby the change in acidity indicators of soils can be predicted as a result of lime application. The experiment was laid out in a randomized complete block design with three replications. Five levels of lime (0, 1.15, 2.3, 3.45, 4.6 t ha-1) and four levels of Phosphorous (0, 10, 20, and 30 kg ha-1) were combined in a complete factorial arrangement. The study was conducted for three consecutive years from 2015 to 2017 main cropping seasons at Banja district. Mean grain yield and yield components as affected by different levels of lime and phosphorus fertilizer. Analysis of variance showed that all limed treatments were higher mean values of grain yield and yield components relative to control plot (no lime and P) in all over combined cropping years. Moreover, over year combined mean the highest grain yields (1115.9 kg ha-1), biomass yields (3591.2 kg ha-1), number of seeds per plant (21.54), plant height (64.50 cm) and spike length (5.24 cm) were recorded under 4.6 t ha-1 of lime application of plot. The lowest grain and biomass yields were recorded in control plots. However, over year mean 4.6 t ha-1 of lime application plot the grain yield and biomass yield of wheat were increased by (151.1%) and (123.3%) related to the control plot, respectively. Hence, lime application at the rate of 3.45 t ha-1 (150% of the lime requirement of the soils based on its exchangeable acidity) coupled with 20 kg ha-1 P fertilizer could serve as a reference to boosting wheat production in the study area and similar areas with possible re-liming of the soils in every five years.

Quantifying the Effects of Modifications to the Sikora Buffer pH Method for Oregon Soils

ABSTRACT The Sikora buffer pH method is a non-hazardous alternative to the Shoemaker, McLean, and Pratt (SMP) method for lime requirement estimation (LRE) for Oregon soils. Commercial soil testing laboratories may implement method modifications in order to streamline the method for large-scale testing, however the potential effects of these modifications on buffer pH results are currently unknown. Modifications that artificially increase buffer pH are of particular concern, as they could potentially result in under-application of lime and crop damage. The goal of this project was to evaluate and quantify five Sikora buffer pH method modifications for five Oregon agricultural soils. Soil type did not show a significant interaction effect with method modifications. Modifications related to mixing method, measurement in supernatant instead of slurry, and soil:water:buffer ratio were found to significantly increase Sikora buffer pH results by 0.063, 0.065, and 0.058 units, respectively, in comparison to the control. Mean Sikora buffer pH decreased by 0.02–0.05 units when equilibration time was increased from 0 to 180 min. Our findings show how even minor modifications can alter Sikora buffer pH results, illustrating the importance of avoiding deviations from the original method. Additionally, comparing results among labs may help minimize over- or under-recommending of lime to agricultural fields.

A summary of research results on pasture responses to fertiliser and lime in the South Island hill and high country

The published results from trials used to determine nutrient and lime requirements of legume-based pastures in South Island hill and high country are summarised. Most of the research in the 1950’s and 1960’s found that sulphur (S) alone was required on the less weathered and leached Semi-arid and Pallic soils but both S and phosphorus (P) were required on the more weathered and leached Brown soils. The severe lack of S necessitated the application of rapidly plant-available S as gypsum. Research in the 1970’s and 1980’s determined the most effective particle size ranges in relation to frequency of application of elemental S to provide adequate S. This work highlighted a need for sufficient S for legume growth before a growth response to P was measured on most soils which has resulted in the manufacture of a range of suitable sulphur fortified superphosphate products. During this 40-year period a limited amount of work showed that nitrogen (N) fertiliser could enhance the growth of resident grasses and legumes and that added S could improve the response. Molybdenum (Mo) has been the only trace element that has been lacking for pasture growth and research has been reported that defines optimal rates, frequency of application and criteria for interpretation. In the last 20 years, the need lime to alleviate soil aluminium (Al) toxicity on these mainly acidic soils has been demonstrated to allow legumes to establish and persist. 
 Current gaps in available information indicate potential areas for more research. These gaps include identifying responses to rates of P and S on pasture with varying legume content on different hill slopes, differential application of elemental sulphur and lime on shady aspects of Semi-Arid and Pallic soils, definition of P and S requirements of pure legume swards, the role of fertiliser N to improve legume establishment, fertiliser and management options to break down thatch at the soil surface and improve legume establishment, determination of the soil and landscape factors that affect the spatial variability of soil Al concentrations, further confirmation of the role of lime injection into soil layers with high soil Al toxicity, the assessment of test strips of applied Mo to assist in the identification of deficiencies in legumes and the combination of information into a decision support system to aid farmers in their selection of legume species and fertiliser and lime requirements for different areas of their farms.

Productivity of Groundnut as Influenced by Integrated Use of Lime, Organics, Inorganic Fertilizers, and Biofertilizers in Acidic Soil of Tripura

A field experiment was carried out on acidic soil of Khowai district of Tripura during 2017 and 2018 to study the effect of application of various combinations of lime, farmyard manure (FYM), poultry manure (PM), and rhizobium with the recommended doses of NPK on groundnut (Arachis hypogaea L.) productivity. The experiment was conducted in a completely randomized block design with 13 treatments; each replicated thrice. The application of the recommended dose of NPK @ 20:60:40 kg ha-1 along with lime @ 1/5th Lime Requirement (LR), PM @ 5 t ha-1 and seed treatment with Rhizobium @ 20 g kg-1 of seed significantly increased the seed yield and recorded the highest Benefit : Cost ratio (B:C) compared to the recommended dose of NPK alone as well as other treatments combinations. Thus, in achieving higher groundnut productivity with better return in acidic soils of Tripura, integrated use of inorganic fertilizers (NPK @ 20:60:40 kg ha-1) combined with lime @ 1/5th LR, PM @ 5 t ha-1, and seed treatment with Rhizobium @ 20 g kg-1 of seed might be recommended.

Digital soil survey and mapping underpinning inherent and dynamic soil attribute condition assessments

We set out in this work to create a suite of 3D-like digital soil attribute maps for a research farming enterprise situated in the South Eastern Agricultural Zone of NSW, Australia. These digital maps come about because of a reconnaissance soil survey to map out the farm's soil baseline conditions and bring to bear the tools and processes of the digital convergence. This entails on-the-go proximal soil sensing for rapid and granular farm landscape characterisation, which helped inform field-based soil survey and sampling, and later the soil mapping too. Soil infrared spectroscopy associated inference (vis-NIR) was then used to facilitate very detailed soil characterisations of key soil attributes that included soil pH, carbon, soil texture, bulk density, and cation exchange capacity amongst others. This work then enabled the ability to build bespoke spatial models to generate 3D-like inherent and dynamic digital soil attribute maps. We highlight some of the digital soil infrastructure features which include flexibility, customisation, and work pipelines that will ease the updating and improvement of maps. We also highlight some immediate goals which include a formal inclusion of measurement uncertainties brought about by soil spectral inference into the spatial modelling process. To date, some of the digital soil mapping has been used for applications such as lime requirement estimations to address subsoil acidity issues and therefore changing/improving the soil's capability at BARS. Overall, the intention of this work is to provide a detailed account of what is entailed in creating a comprehensive digital soils infrastructure for a farm including the likely costs to implement and the associated opportunities it provides.