Tropic Acid Research Articles

Effects of aluminum toxicity on physiological and leaf chlorophyll fluorescent characteristics of rubber tree seedlings.

Aluminum toxicity is common in tropical acid soils. However, its effects on rubber tree growth and latex production are still unclear. Using potted sand culture seedlings of rubber tree, the effects of different aluminum ion concentrations on physiological and chlorophyll (Chl) fluorescence characteristics were investigated. The results showed that the cell membrane permeability, free proline content, and soluble sugar content were significantly increased, while the relative water content, catalase and peroxidase activities, Chl a content, Chl maximum fluorescence yield, maximum photosynthesis efficiency and potential activity of PSII, photochemical quenching coefficient, non-photochemical quenching coefficient and photosynthetic electron transport rate were significantly decreased when the saplings were subjected to AlCl3 treatments with concentration higher than 200 mmol·L-1. When the AlCl3 concentration was lower than 100 mmol·L-1, the aforementioned parameters did not show any significant variation among different treatments for the entire duration of the experiment. These results indicated that the rubber tree could tolerate some degree of aluminum toxicity. The threshold concentration of aluminum toxicity for rubber tree seedlings would be between 100 to 200 mmol·L-1. When this threshold was exceeded, aluminum toxicity would cause irreversible damage to rubber tree seedlings.

Forms and buffering potential of aluminum in tropical and subtropical acid soils cultivated with Pinus taeda L

Several interactions between Al and the solid phase of soil influence Al buffering in soil solution. This work evaluated soils cultivated with Pinus taeda L. to determine Al forms in organic and mineral horizons using various extraction methods and to relate acidity with clay mineralogy. Organic and mineral horizons of 10 soil profiles (up to 2.1 m deep) in southern Brazil were sampled. Organic horizons were separated into fresh, aged, and fermented/humified litter. The following Al extraction methods were utilized: 0.5 mol L−1 pH 2.8 CuCl2–Al complexed in organic matter; 1.0 mol L−1 KCl–exchangeable Al; water–Al soluble in soil solution; HF concentrated + HNO3 concentrated + H2O2 30% (v/v)–total Al. Six sequential extractions were carried out to isolate different forms of amorphous minerals that can buffer Al on soil solution: 0.05 and 0.1 mol L−1 sodium pyrophosphate; 0.1 and 0.2 mol L−1 ammonium oxalate; 0.25 and 0.5 mol L−1 NaOH. Samples of clay were also analyzed by XRD. There was a clear effect of litter age on increasing total Al concentration. In the aged litter and fermented and/or humified litter, levels of total Al were 1.4 to 3.8 and 1.5 to 7.8 times greater than in fresh litter, respectively. The CuCl2 method had higher Al extraction capacity than the KCl method for litter. The lowest Al–pyrophosphate values were observed in the Oxisol, which also had a predominance of gibbsite and the lowest levels of Al–KCl and Al–CuCl2. There was an inverse relationship between degree of soil weathering and soluble and exchangeable Al in soils. Available Al increased with higher Si proportion in minerals of the clay fraction (2:1 > 1:1 > 0:1). The worst scenario was soils with the combination of high soluble and exchangeable Al levels and high concentrations of amorphous forms of Al minerals. The best predictors of Al accumulation in the youngest litter horizon were extractions of amorphous minerals with pyrophosphate and NaOH. These extractors are normally used to predict the level of Al buffering in soils. Organic matter had less influence on Al dynamics in soils.

Development and Validation of GC-MS Bioanalytical Method to Detect Organic Acidemia in Neonatal/Pediatric Urine Samples

This work was aimed at developing an analytical tool for the simultaneous quantification of methylmalonic acid, glutaric acid, succinyl acetone, homogentisic acid, and pipecolic acid in pediatric urine samples. Organic acids were isolated from urine by liquid-liquid extraction. The extracted samples were then derivatized by using BSTFA + 1% TMCS solution, which resulted in the formation of trimethylsilyl ester derivatives. These analytes were quantified by GC-MS, and this bioanalytical method was validated according to the USFDA guidelines. The proposed method was applied to several clinically suspected organic acidemia samples. The linearity range is within 5 – 100 �g/mL for methylmalonic acid and glutaric acid, 20 – 100 �g/mL for succinyl acetone and homogentisic acid, and 10 – 100 �g/mL for pipecolic acid. Mean % recovery of QC samples of methylmalonic acid, glutaric acid, succinyl acetone, homogentisic acid, and pipecolic acid was found to be 92.06, 92.21, 90.92, 93.17, 90.71%, respectively, and that of tropic acid was 96.57%. All organic acids were stable at room temperature for 8 h. The stability of succinyl acetone, homogentisic acid, and pipecolic acid stored for 30 days at 8°C was found to be lower. The proposed method was applied to the analysis of samples obtained from 23 patients.

High soil Mn and Al, as well as low leaf P concentration, may explain for low natural rubber productivity on a tropical acid soil in Vietnam

ABSTRACTThe aim of the current study was to identify major soil and leaf factors accounting for low natural rubber (NR, Hevea brasiliensis) productivity on tropical acid Acrisols in Vietnam. Twenty NR plots were measured with NR productivity, leaf factors (N, P, K, Ca, Mg, Mn, Cu, Fe, and Zn), soil factors (pH, particle size distribution, total C, N, P, K, exchangeable K, Ca, Mg, Al, Mn, Fe, Zn, available P). Cluster analysis showed that NR productivity could be separated into three clusters with low (23.2), medium (38.2), and high (61.3 g tree−1 harvest−1) yield. High-yield cluster had higher leaf P concentration and soil pH, while low-yield cluster had higher leaf Mn, soil exchangeable Al, and Mn concentration. Simple and multiple linear regression analysis applied with backward elimination procedure suggested that leaf and soil toxic concentration may be responsible for low NR productivity in the study soil.

Partitioning and potential mobilization of aluminum, arsenic, iron, and heavy metals in tropical active and post-active acid sulfate soils: Influence of long-term paddy rice cultivation

Drainage of potential acid sulfate soils (PASS) for paddy rice cultivation results in the formation of active acid sulfate soils (AASS) and subsequently post-active acid sulfate soils (PAASS). The drainage of PASS causes severe environmental problems including acidification and metal contamination of soil and water resources. This study examined the vertical distribution and partitioning of Al, As, Co, Cu, Fe, Mn, Ni, Pb, and Zn in six tropical acid sulfate soils representing AASS and PAASS under long-term paddy rice cultivation (>145 years). The bulk soil samples were analyzed for total concentrations of Al, As, Co, Cu, Fe, Mn, Ni, Pb, and Zn. The partitioning of these elements was examined by a sequential extraction procedure. Labile Al is higher in ASS which is associated with low soil pH. During drainage, mobilization of As, Cu, and Pb is limited by coprecipitation with (poorly) crystalline Fe oxides minerals in the topsoil and partly oxidized layer of both soil types. These elements are associated with iron (mono) sulfides in unoxidized layer. When PASS are exposed to air, Co, Mn, Ni, and Zn are leached from the soils and are dominantly associated with iron sulfides in the unoxidized sediments. Labile Mn, Ni, and Zn are elevated in the unoxidized layer of PAASS because these elements are leached from the partly oxidized layers and adsorbed onto soil constituents. Cobalt is probably precipitated or adsorbed onto (poorly) crystalline minerals.

Intensive annual crop production and root development in a tropical acid soil under long-term no-till and soil-amendment management

In tropical conservation agricultural systems, crop yield is limited by soil acidity and root-growth inhibition, especially under intensive crop rotation. This study evaluated the effect of surface applications of lime and phosphogypsum in improving soil fertility and crop yield in a tropical region. Four treatments were evaluated: control (without soil amendment); and application phosphogypsum (2.1 + 2.1 + 2.1 Mg ha–1), lime (2.7 + 2.0 + 2.0 Mg ha–1), and a combination of lime and phosphogypsum at the given rates, applied in 2002, 2004 and 2010, respectively. We evaluated the soil chemical properties, root development, plant nutrition, yield components and grain yield of 10 crops over 4 years using five species: maize (Zea mays), crambe (Crambe abyssinica), cowpea (Vigna unguiculata), wheat (Triticum aestivum) and common bean (Phaseolus vulgaris). Our long-term results demonstrate the benefits of surface liming in alleviating subsoil acidity, reducing Al3+ toxicity, improving availability of Ca2+ and Mg2+, and increasing accumulation of soil organic matter in all soil profiles at depths up to 0.60 m. For maize and crambe, adding phosphogypsum increased development of plants and reproductive structures, which increased grain yield. Phosphogypsum exhibited synergistic effects in association with lime for maize and common bean. Phosphogypsum did not have an effect on cowpea and wheat, whereas surface liming was essential to improve plant nutrition, grain yield and wheat grain quality. The combination of both soil amendments is an important tool to reduce the soil acidification process, resulting in the highest levels of Ca2+ and Mg2+ and the highest base-saturation values in the topsoil layers (0–0.20 m) over time. Our long-term results showed the viability of surface liming plus phosphogypsum for improving tropical soil fertility, which can reflect an increase in grain yield and contribute to the sustainability of agricultural systems under intensive land use in highly weathered areas.

Effects of incubation period and Christmas Island rock phosphate with different rate of rice straw compost on phosphorus availability in acid soil

Phosphorus (P) availability is limited in tropical acid soil due to fixation of soluble inorganic P by aluminium (Al) and iron (Fe). Liming is one of the common ways to overcome this problem. However, this practice is not economical. The aim of this study was to evaluate the effects of laboratory incubation period and different rates of rice straw compost on the soil P availability. During the incubation study, Christmas Island rock phosphate (CIRP) fertilizer was amended with different rates of rice straw compost (5, 10, 15, and 20 t ha−1). Treatments were incubated in the laboratory for 30, 60, and 90 days. Application of rice straw compost with CIRP significantly increased soil available P at 30, 60, and 90 days of incubation, respectively. This implies rice straw compost plays an important role on soil P availability by decreasing the P adsorption due to the competing adsorption sites by organic anion and dissolving the mineral associated P by low-molecular-weight organic acids. Besides, rice straw compost also increased the soil pH, and, at the same time, reduced exchangeable acidity, exchangeable Al and Fe. As the soil pH increased, the compost effectively fixed the Al and Fe in the soil instead of P, thus increasing the P availability in the soil. However, there was no significant increase/loss of available P when the incubation time increases under treatments with rice straw compost. This implies the effectiveness of rice straw compost in minimizing the loss of P due to P fixation in soil and slow microbially mediated mineralization of soil organic P to inorganic P as incubation time increases. The findings suggest that the application of rice straw compost altered soil chemical properties in a way that enhanced the availability of P in the Rengam acidic soil.

Kinetic study on extractive resolution of tropic acid by hydroxyethyl-β-cyclodextrin

Reactive extraction is proposed as a promising approach to the resolution of tropic acid (TA), where hydroxyethyl-β-cyclodextrin (HE-β-CD) is used as a selective extractant. The reaction between tropic acid and extractant occurred in the aqueous phase, and kinetic studies of reactive extraction have been investigated in a Lewis-type stirred cell. The batch experiments have been performed to study the process parameters affecting the extraction rate including agitation speed, interfacial area, pH value of aqueous phase, initial concentration of tropic acid enantiomers and initial concentration of extractant on the initial extraction rate. The kinetic equation of the forward rate was deduced at the experiment condition: r TA+ = (4.041 × 10−3)[TA+][CD]2; r TA− = (3.1234 × 10−3)[TA−][CD]2.

Soil pH Buffering Capacity and Nitrogen Availability Following Compost Application in a Tropical Acid Soil

ABSTRACTTropical acid soils are highly weathered as they exist under tropical environment with high rainfall and temperature throughout the year, which affects nitrogen availability. Soil organic nitrogen is important in estimating soil nitrogen availability. The combined use of urea and compost in this study was carried out to decrease sole dependence on urea, buffer soil acidification, and reduce nitrogen losses through leaching. Thus, soil buffering capacity, incubation, and organic nitrogen fractionation studies were conducted to determine soil buffering capacity, availability of total nitrogen, organic fractions nitrogen, and inorganic nitrogen in soil after 90 days of incubation following compost. Soil pH, buffering capacity, total nitrogen, organic nitrogen fractions, exchangeable ammonium, and available nitrate were higher in all treatments with compost and combined use of urea and compost. Total hydrolyzable nitrogen, ammonium-nitrogen, (ammonium + amino sugar)-nitrogen, amino sugar-nitrogen, and amino acid-nitrogen were higher in soils with urea and compost suggesting that decomposition of soil organic fractions nitrogen into inorganic nitrogen (ammonium and available nitrate was affected by the addition of urea and compost. Urea can be amended with compost to regulate availability nitrogen in soil for crop use.

Assessment of Potential Nutrient Release from Phosphate Rock and Dolostone for Application in Acid Soils

Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions (0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at pH 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size, leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased, corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.

The Role of Soil Amendment on Tropical Post Tin Mining Area in Bangka Island Indonesia for Dignified and Sustainable Environment and Life

Openly tropical tin mining in Bangka Island Indonesia expose heavy metal that had been buried became a part of our environment and life. This has become a major cause of land degradation and severe local-global environmental damages. This study aims to accelerate reconsolidation of degraded ecosystems on the former tin mine land, to increase land productivity and dignified environment through appropriate rehabilitation technology on marginal land that is inexpensive, environmentally friendly and sustainable. This study is a part of a roadmap research activities on the rehabilitation of degraded land in tropical ecosystem, that consist of (a) characterization of degraded tin mining lands through the determination of chemistry, physics, biology and mineral soil properties, (b) introducing multi-function pioneers plant for acceleration of peak pioneer plant in the reestablishment of degraded tin mining ecosystem (c) management of natural soil amendment (volcanic ash, organic waste materials and legume cover crop as a material for soil amelioration to increase land productivity, (d) role of biotechnology through the application of local bio-fertilizer (mycorrhizae, phosphate soluble bacteria, rhizobium). Soil from post tropical tin mining acid soil (pH 4.97) that dominated by sand particles (88%) with very low cation exchange capacity, very low nutrient contents (available and total-N, P, K, Ca, Mg) and high toxicity of Zn, Cu, B, Cd and Ti, but still have low toxicity of Al, Fe, Mn, Mo, Pb, As. Soil amendment of biogas and volcanic ash could improve soil quality by increasing of better pH, high available-P and cation exchange capacity and maintained their low toxicity. The growth (high, diameter, biomass, top-root ratio) of exotic pioneer plant of Kemiri sunan (Reutealis trisperma) increased in the better soil quality that caused by application of proper soil amendment. The grand concept and appropriate technology for rehabilitation of degraded tin-mining land ecosystems in tropical regions which are the lungs of the world have a high contribution for development of our dignified and sustainable environment and life.

Construction and application of a model on the resolution of tropic acid enantiomers by enantioselective liquid-liquid extraction in centrifugal contactor separators

Abstract This paper reports on the construction and application of a mathematical model on multistage liquid-liquid extraction of tropic acid (TA) enantiomers in centrifugal contactor separators (CCSs). An efficient extraction system was obtained, where HE-β-CD and butyl acetate was selected as the best extractant and organic solvent. The mechanism of reactive extraction of TA enantiomers by HE-β-CD was proposed and the thermodynamic constants such as physical partition coefficient and reactive equilibrium constants were obtained, which combined with the law of mass conservation gave the basis for construction of the model. The model was applied to predict and optimize the symmetrical separation of TA enantiomers. The optimal condition was obtained as follows, O/W volume ratio of 3.0, pH of 3.00 and HE-β-CD concentration of 0.05 mol/L, where ee eq (equal enantiomeric excess) can reach up to 42%. The simulated results reveal that the minimum number of stages for ee eq > 97% and ee eq > 99% was 56 and 78, respectively.

Molecular Modeling of an Electrophilic Addition Reaction with “Unexpected” Regiochemistry

The electrophilic addition of a hydrohalic acid (HX) to an alkene is often one of the first reactions learned in second-year undergraduate organic chemistry classes. During the ensuing discussion of the mechanism, it is shown that this reaction follows Markovnikov’s rule, which states that the hydrogen atom will attach to the carbon with fewer substituents while the halogen atom will attach to the carbon with more substituents. However, in the preparation of tropic acid, the reaction of HCl with atropic acid (2-phenylpropenoic acid) does not follow this rule because it is a conjugated system. Molecular modeling of the possible carbocation intermediates suggests that the reaction follows a conjugate addition mechanism involving a 1,4-addition of HCl across the conjugated alkene and carboxyl group rather than addition across the alkene as students often first propose. PM3 semiempirical calculations are used to determine the energies of three possible carbocation intermediates. The energies obtained from the modeling suggest that the carbocation intermediate produced by the 1,4-addition is the most stable.

Lime and phosphogypsum impacts on soil organic matter pools in a tropical Oxisol under long-term no-till conditions

Improving soil organic matter (SOM) quality in tropical acid soils is important for increasing the sustainability of agricultural ecosystems. This research evaluated the effect of the surface application of lime and phosphogypsum on the quality and amount of SOM in a long-term crop rotation under no-till conditions. The research was performed in a kaolinitic, thermic Typic Haplorthox for 12 years with annual crops under no-till. The treatments included no soil amendments, and amendment with phosphogypsum, lime, and lime+phosphogypsum. After three applications of soil amendments (2002, 2004, and 2010), surface liming increased the SOM input through addition of aboveground and root biomass, varying amount according to crop species, growing season, and soil depth. Although phosphogypsum had no effect on plant biomass production, the application of phosphogypsum with lime increased nitrogen (N) by up to 50% in the uppermost soil depths. The application of lime alone significantly increased the total organic carbon (TOC) at all depths, although the greatest effects were observed at 0.10–0.20 and 0.20–0.40m, with an increase of 44% and 41%, respectively. Moreover, lime+phosphogypsum also exhibited the highest potential for C mineralization, which was attributed to an increased proportion of TOC as particulate organic carbon (POC). The proportion of TOC as humin and fulvic acid increased with the application of lime+phosphogypsum at 0–0.05m, with an increase from 55% to 92% and from 1.4% to 1.6%, respectively. Overall, the combination of lime and phosphogypsum increased both the labile and stable C pools.

Effects of biochar, urea and their co‐application on nitrogen mineralization in soil and growth of Chinese cabbage

AbstractExperiments were conducted to study the effect of soil applications of kunai grass (Imperata cylindrica) biochar (0 and 10 t/ha) and laboratory grade urea (0, 200 and 500 kg N/ha) and their co‐application on nitrogen (N) mineralization in an acid soil. The results of an incubation study showed that the biochar only treatment and co‐application with urea at 200 kg N/ha could impede transformation of urea to ammonium‐N (NH4+‐N). Soil application of biochar together with urea at 500 kg N/ha produced the highest nitrate‐N (NO3−‐N) and mineral N concentrations in the soil over 90 days. Co‐application of urea N with biochar improved soil N mineralization parameters such as mineralization potential (NA) and coefficient of mineralization rate (k) compared to biochar alone. In a parallel study performed under greenhouse conditions, Chinese cabbage (Brassica rapaL. ssp.chinensisL.) showed significantly greater (P < 0.05) marketable fresh weight, dry matter production and N uptake in soil receiving urea N at 500 kg/ha or co‐application of biochar with urea N compared to the control. Application of biochar only or urea only at 200 kg N/ha did not offer any short‐term agronomic advantages. The N use efficiency of the crop remained unaffected by the fertilizer regimes. Applications of biochar only at 10 t/ha did not offer benefits in this tropical acid soil unless co‐applied with sufficient urea N.

Development and Application of a Validated UHPLC Method for the Determination of Atropine and Its Major Impurities in Antidote Treatment Nerve Agent Auto-Injectors (ATNAA) Stored in the Strategic National Stockpiles

The development and implementation of advanced analytical technologies is essential for extending the expiry for complex drug products stored in the Strategic National Stockpiles. Consequently, a novel Ultra High-Performance Liquid Chromatographic (UHPLC) method has been developed for the analysis of atropine and its respective impurities to support the analytical research platform for auto-injectors. This study is part of a larger research effort to improve the efficiency and broaden the applicability of advanced analytical methods for medical counter-measure medications. The current HPLC compendial methodology for atropine sulfate injection requires an analysis time of 40 minutes for atropine. In comparison, the novel gradient UHPLC method required only 8 minutes to evaluate both atropine and its major pharmaceutical impurities. Improved separation was achieved on a Waters Acquity UHPLC BEH C18 1.7 μm, 2.1 × 100 mm column employing gradient elution of mobile phase solvent A (0.1% H3PO4) and solvent B (0.1% H3PO4, 90% ACN, and 10% H2O). The method was validated according to USP Category I requirements for assay. The daily standard calibration curves were linear over a concentration range from 50 μg/mL to 250 μg/mL with a correlation coefficient of >0.999. The detection limit (LOD) and quantitation limit (LOQ) were 3.9 μg/ml and 13.1 μg/ml, respectively. Resolution results indicate that atropine and the following impurities, degradants and a preservative can also be separated and analyzed using this proposed method: noratropine, 4,4’-di-hy-droxydiphenyl ether, 2,4’-dihydroxydiphenyl ether, 4-bromophenol, 4-hydro-xyatropine, tropic acid, apoatropine HCl, atropic acid, hydroquinone, nitroethane, phenol and catechol. The UHPLC method demonstrated enhanced selectivity and significantly reduced the analysis time when compared with the traditional USP compendial HPLC method. The method was successfully applied to the evaluation of atropine in ATNAA auto-injectors lots from the Strategic National Stockpiles.

Efficacy evaluation of empty palm oil fruit bunch compost in improving soil characteristics, plant growth and disease suppression of tomato plants under tropical acid soil

Efficacy evaluation of empty palm oil fruit bunch compost in improving soil characteristics, plant growth and disease suppression of tomato plants under tropical acid soil

Buscopan labeled with carbon‐14 and deuterium

Hyosine butyl bromide, the active ingredient in Buscopan, is an anticholinergic and antimuscarinic drug used to treat pain and discomfort caused by abdominal cramps. A straightforward synthesis of carbon-14- and deuterium-labeled Buscopan was developed using scopolamine, n-butyl-1-14 C bromide, and n-butyl-2 H9 bromide, respectively. In a second carbon-14 synthesis, the radioactive carbon was incorporated in the tropic acid moiety to follow its metabolism. Herein, we describe the detailed preparations of carbon-14- and deuterium-labeled Buscopan.

Improving the fertility of tropical acid soils: Liming versus biochar application? A long term comparison in the highlands of Madagascar

Soil acidity is a major constraint for crop production on highly weathered tropical soils characterized by high Al toxicity, low cation exchange capacity and low P availability to plants. To address these constraints, we compared the effects on crop production and soil properties of liming and adding biochar. Experiments were conducted under field conditions in an acidic soil in the Madagascar highlands using a two year rotation of maize intercropped with beans followed by rainfed upland rice over a period of six years. Five different levels of amendment were compared: 10 and 50tha−1 of eucalyptus charcoal residues (referred to as biochar), 1 and 3tha−1 of dolomite and a control (no amendment). They were combined with two types of soil management (conventional tillage and no tillage) and two fertilization levels. Soil characteristics were measured once after five years. Both biochar and dolomite amendment significantly improved yields of the maize and beans due to an increase in soil pH and a decrease in exchangeable aluminium. However, no significant effect was observed on the yield of upland rice. The incorporation of 50tha−1 of biochar was necessary to match the results obtained with 3tha−1 of dolomite. Amendment with dolomite was a more practical and cost-efficient option than amendment with biochar in our conditions. Long term trials are now needed to evaluate other types of biochar.

Reducing Soil Phosphorus Fixation to Improve Yield of Maize on a Tropical Acid Soil Using Compost and Biochar Derived from Agro-Industrial Wastes

ABSTRACTPhosphorus is an essential element required to maintain profitable crop production. Most soils of the tropics, such as Ultisols, are acidic and fix phosphorus because of their characteristically high contents of aluminium and iron. Compost and biochar could be used to mitigate phosphorus fixation by reducing the phosphorus sorption sites. This study aimed to: (i) improve soil phosphorus availability, nutrient uptake, and yield of maize using biochar and pineapple leaf residue compost; and (ii) determine if the use of biochar and compost could exert a residual effect on phosphorus nutrition in the second cycle of the field trial. Field trials were carried out using a Zea mays L. hybrid as the test crop. At harvest, the plants were harvested, partitioned into leaves and stems, and analyzed. Soil samples were also collected and analyzed. Ears were harvested to determine the yield from each treatment. The results suggest that the soil total phosphorus and available phosphorus recovered from the treatments with the organic amendments were higher compared with the non-organic amendments. The availability of soil nutrients (nitrogen, potassium, calcium, magnesium, and sodium) in the soils and yield of maize were higher in the treatments with the organic amendments in the first and second field trials. These results further confirm that amending chemical fertilizers with organic amendments have a larger residual effect than chemical fertilizers only. Amending chemical fertilizers with organic amendments can be used to ameliorate phosphorus fixation of acid soils to improve maize production on acid soils.