Tropical Soils

The impact of salinity on paddy production in Indonesia was pronounced with an average decline of 6.83% (2015-2019). Salinity interferes with macronutrients' absorption into plants, causing stunted growth (salinity contributed to a 42% decrease in paddy production). One solution to solve the salinity problem in paddy is to use saline varieties. There were very few studies on macronutrient content analysis in resistant varieties response to the salinity source's distance.  This research conducted in Jabon Sidoarjo, Indonesia, aims to see the macronutrient response and plant growth to the saline source's distance. This research was conducted in Jabon District, Sidoarjo Regency, using two transects with a length of 2 km and 3.4 km, respectively. The distance between the research location and the salinity source was 10.65 km.  The survey used a free grid to adjust paddy fields' location and the presence of resistant varieties. The results showed that the closer to the sa...

In the northern Pantanal wetlands of Brazil, alkaline sodic soils play a significant role in the ecological functioning of the region, but little is known about their mineralogical equilibria in current flooding dynamics which is necessary for good management of these areas. This study focused on a transition between sodic and non-sodic soils, identified by low frequency electromagnetic induction survey. Samples of B horizons from alkaline-sodic and non-sodic soils were analyzed via soil solution from saturated paste, decomposition of X-ray diffraction (XRD) patterns and Transmission Electron Microscopy with X-ray dispersive energy spectroscopy (TEM-EDS) analysis. The transition between alkaline-sodic and non-sodic soils matches with the transition between flooded and non-flooded areas. The soil solution shows a concentration factor of about 40 along this transition. The formation of sodic soils results from an accumulation by evaporation of solutions with a positive calcite residual alkalinity (RAcalcite), probably imposed by the chemistry of the São Lourenço River. An increasing Na:Ca ratio caused solonization of the exchange complex. These alkaline-sodic soils, however, can be interpreted as declining soils in the current context with an evacuation of soluble salts during flood cycles. The detailed investigation of the fine clay fraction (< 0.2µm) using full profile modelling and decomposition of XRD patterns and TEM-EDS analysis demonstrates gradual transformations of trioctahedral to dioctahedral smectite by Mg-Al substitutions on octahedral sites, leading to the prevalence of kaolinite-smectite interstratified minerals when the conditions become more acidic via solodization process.

In order to evaluate the effects of long-term phosphorus fertilizer application on the sawah soils, a comparative study was conducted in Java Island as a pioneer of Green Revolution (GR) technology application in Indonesia. Soil samples taken in 1970 by Kawaguchi and Kyuma were compared with new sample taken from the same site or the sites close to 1970 in 2003. The results showed that available phosphorus (P) sharply increased during the study period. The average content of available P in topsoil layer changed from 10.5±11.6 mg kg-1 P in 1970 to 19.6±22.4 mg kg-1 P in 2003, or increased by 118%. Long-term application of 125 kg super-phosphate [Ca(H2PO4)2] per hectares per cropping season as P fertilizers was also affected the profile distribution of available P in whole sites studied, especially in Vertisols. The land management differences between seedfarms planted with rice in monoculture systems whole study period and non-seedfarms cultivated rice and upland crops in some rotati...

It has been established that iron oxides and hydrous oxides constitute an important component of tropical soils. Most of these oxides are in the form of amorphous and crystalline particles. The dominant source of soil colour has been attributed to the crystalline oxide, hematite . A small fraction of iron also exists in the form of organic complexes. Selective extractions of the various iron fractions have been found to be useful in pedogenetical studies of temperate soils &gt; and tropical soils&#39; s . Bascomb had shown that a particular method, although specific, can also extract different forms of iron, but despite this limitation, these studies showed that the methods can be utilised to characterise the nature of iron in soils.

Tin mining operations on the Jos Plateau have left a lasting impact on the environment, resulting in derelict land, mine spoils, and over a thousand abandoned mining ponds. These ponds have become potential hazards, endangering unsuspecting members of the public. This study aims to provide a comprehensive geochemical and geotechnical characterization of the mine spoils to assess their suitability for the reclamation and restoration of the degraded mined lands. The geochemical analysis reveals that the mine spoils exhibit a moderate to strong level of acidity, with a pH range of 3.91 to 5.90 (average: 4.85). Furthermore, they display deficiencies in essential nutrients such as phosphorus (average: 0.02%) potassium (average: 0.31%), as well as copper (average: 19.15 ppm). Notably, the mine spoils are enriched in iron (average: 6.31%), manganese (average: 165.15 ppm) and zinc (average: 53.24 ppm). These findings highlight the inadequate presence of both micronutrient and macronutrient elements which are necessary for successful revegetation, a crucial component of reclamation. Results from the geotechnical tests indicate that the mine spoils possess an average fines content of 56.03%, a mean liquid limit of 38.06%, and a mean plasticity index of 15.52%. Additionally, the average linear shrinkage value is measured at 10%. The average values for maximum dry density (MDD) and optimum moisture content (OMC) are 1.65 g/cm³ and 19%, respectively. The unsoaked California bearing ratio (CBR) averages 34.64%, while the coefficient of permeability for the spoil is approximately 1.24x10 −3 mm/sec. Furthermore, the spoils average cohesion (C) was measured to be 12.15 0 while the mean angle of internal friction (ϕ) is 30.77 KN/M 2. These results collectively indicate that mechanical and chemical stabilization, involving the use of lime, fly ash, and other soil-stabilizing agents is imperative for the effective reclamation of the degraded lands using the mine spoils. Such measures if adopted and implemented will mitigate the risk of accidents and drowning incidents from mining ponds and other abandoned pits involving unsuspecting members of the public and will contribute to the overall environmental restoration efforts in the Jos-Bukuru Tin Field.

Limited databases on water retention and availability in soils to generate pedotransfer functions are available for tropical and subtropical soils. The objectives of the study were to generate and evaluate pedotransfer functions for soil water retention in soils from subtropical Brazil; and to estimate plant available water based on soil particle size distribution. Two databases were set up for soil properties including water retention: one had 725 data and the other 253 data. From the literature database, pedotransfer functions were generated, nine pedofunctions available in the literature were evaluated and the plant available water capacity was calculated. Pedotransfer functions for selected sections generated for the soils had coefficients of determination ranging from 0.56 to 0.66. Pedotransfer functions generated with soils from other regions were not appropriate for estimating the water retention. Plant available water content varied with soil texture class, from 0.089 kg kg ...

Resumo: A capacidade produtiva da agricultura tradicional de corte e queima pode ser melhorada por meio do plantio de árvores de crescimento rápido durante o período de pousio, com o objetivo de acumular biomassa e nutrientes para uso na fase agrícola subsequente. Para isso, são desejados alguns atributos das espécies florestais a serem usadas no enriquecimento da capoeira. O plantio das espécies florestais leguminosas Acacia mangium (acácia), Inga edulis (ingá), Acacia angustissima (ligeirinha) e Sclerolobium paniculatum (taxi-branco), a partir da fase agrícola (milho e mandioca), no espaçamento 2 m x 2 m, apresentou bons resultados para a porcentagem de sobrevivência, acúmulo de biomassa e volume de madeira. O acúmulo de biomassa seca proporcionado pelas árvores plantadas variou de 35-40 t ha-1 (acácia) a 10-15 t ha-1 (taxi-branco). A análise do impacto do enriquecimento na redução do tempo de pousio mostrou que o sistema de enriquecimento formado com A. mangium proporcionou, em três anos (um ano de cultivo agrícola + dois anos de pousio enriquecido), um acúmulo de biomassa equivalente a cinco anos de pousio tradicional.

Assessment adaptation of several new superior rice varieties  on new rice fields affected by seawater intrusion was carried out in Tungkal Ilir Subdistrict, West Tanjung Jabung District, from April to October 2018. The study applied randomized block designs (RBD) with four replications. The treatments consisted of four new rice high yielding varities suitable for tidal/swamps areas namely Inpara 3, Inpara 8, Inpara 9, and Inpari 34 Salin Agritan, and one local rice variety (Londo) as control. Three stems seedlings per clump were planted at the age of 21-25 days, using a 4:1 Legowo planting system. Fertilizer application consisted of basic fertilizer (1.0 Mg ha-1 of lime, 2.5 Mg ha-1 of manure, and 75 kg ha-1 of urea) and supplementary fertilizer (SP-36 150 kg ha-1 and KCl 125 kg ha-1),. Urea supplementation is given based on observations with a leaf color chart (LCC). The results of the study showed that the four new rice HYVs were more adapted as compared to the local rice variety....

This study measured CO2 flux by segregating effect of root respiration and organic matter decomposition by microbes. The study involved a mineral soil containing high organic matter (Andisols), in the tropic devoted to different land uses i.e. natural forest, tea plantation, and horticultural farm CO2 emission from those land uses were compared to from peatland. Observed CO2 fluxes came out in the following order: bare plot  7.32, tea plantation  10.22, horticultural farm  15.60, and natural forest  15.62 Mg C-CO2 ha-1 yr-1. While, root respiration accounted for substantial proportions: tea plantation  28%, horticultural farm  53%, and natural forest  53%. Soil temperature demonstrated a significant positive correlation with the CO2 flux, except in the natural forest. On the other hand, water-filled pore spaces displayed varying correlation with site CO2 flux: a negative relationship in both bare plot and tea plantation, appreciably positive in the horticultural farm, and weakly rel...

The higher national rice demand encourages various efforts to increase rice production. This increase in rice production occurs in line with increasing public awareness of healthy foods, especially organic rice. Rice field management with an organic system is expected to provide a higher yield and quality of rice. This study aims to determine the effect of the long-time application of an organic rice management system on rice yield and quality. Descriptive exploratory research is supported by laboratory analysis of samples of organic rice plants with three periods (10 years, 7 years, and 4 years), semi-organic and conventional. The parameters observed were dry harvested grain, dry milled grain, the weight of 1000 grains, unfilled grain, protein content, amylum, amylopectin, and reducing sugar. The most prolonged organic rice field management with the application of 10 years gives better results with a protein content of 6.14%, amylum 71.71%, and amylopectin 49.35%. While the applica...

This paper presents the geochemical study of agricultural soil and river sediments along Sumani watershed, West Sumatra in Indonesia. We examined the distribution and abundances of 16 elements (Pb, Zn, Cu, Ni, Cr,V, Sr, Rb, Ce, Th, Zr, Si, Ti, Fe Ca, and P) in vegetable soil, sawah soil =and river sediment sample, to evaluate the factors controlling their abundances, possible sources, and environmental implications. Average concentrations of Pb, Zn, Cu, Ni, Cr,V, Sr, Rb, Ce, Th, Zr at vegetable (1) soil were 38, 88.3, 38.7, 3, 8, 101, 96, 98, 87, 31 and 218 mg kg-1 , 26, 39.05, 8.8, 13.5, 31, 231.5, 37, 19, 78, 16 and 303.5 mg kg-1 at sawah soil (3, 4) and 30, 61.6, 35.7, 9, 22, 294, 65, 12, 78, 14 and 232 mg kg-1 at river sediment (2), respectively. The concentration of Pb, Rb, Th and Zr at upland vegetables, V and Zr at sawah soil and river sediment were mostly two time Sumatra BCSCST or BCC in several samples. Enrichment factor values showed low to moderate enrichment of Pb, Zn, ...

This study aims to determine effect of Vesicular-Arbuscular Mycorrhizae and Liquid Organic Fertilizer application to the phosphorus concentration on soybeans grown in acid soils of post-coal mining. The research use completed randomized factorial design, consisted of two treatment: (1) Vesicular-Arbuscular Mycorrhizae Inoculation, M0= 0 gr, M1= 10 gr, M2= 20 gr, M3= 30 gr, and M4= 40 gr per plant. (2) Liquid organic fertilizer application ,P0= 0 mL, P1= 10 mL and P2= 20 mL per plant .The results showed that the inoculation of Vesicular-Arbuscular Mycorrhizae as much as 40 grams and 20 mL of Liquid Organic Fertilizer gave the best result to the increased concentrations of phosphorus in plant tissue but did not show any increased in the phosphorus concentrations of soil.

Topography significantly influences soil development and characteristics within an uneven agricultural field. Therefore, a comprehensive understanding of soil attributes and processes through detailed pedological knowledge is crucial for effective soil management. This research was carried out in Wasinmi, southwestern Nigeria, to delineate and categorise the soils across different slopes for agricultural insights. Three soil profiles were excavated across the topographical sequence, specifically designated as upper, middle, and lower slope positions. The prevailing soil texture was sandy loam with a discernible trend of lighter soil colour as the slope descended and soil depth increased. The pH of the soil ranged from moderately acidic to slightly acidic. The saturated hydraulic conductivity and soil organic matter content were lowest on the lower slope. Available phosphorus distribution varied inconsistently with higher concentrations of heavy minerals observed at the upper slope. The study underscored the influential role of topography in soil property variations and the need for tailored management practices. The classification of the soils revealed Typic Plintustults in the upper and middle slope positions, while the soils in the lower slope were identified as Typic Kandiaquults. This study demonstrated that topography significantly influenced soil properties, thereby emphasising the need for informed practices to better support the long-term sustainability of land use and agricultural outputs in topographically diverse landscapes.

The study examined the composition and forms of iron and aluminium oxides in benchmark soils of central southwestern Nigeria. Soils developed from distinct parent rock types, including coarse-grained granite and gneiss, fine grained biotite gneiss and schist, and the amphibolite complex which correspond to the parent rocks of the soils of Iwo (Typic Paleustults), Egbeda (Rhodic Kandiustults) and Itagunmodi (Typic Haplustults) Associations, respectively, were selected for the study. Notably, these soils collectively encompass approximately 60% of the total land area in central southwestern Nigeria. The less than 2 mm soil fractions were pre-treated with hydrogen peroxide to remove soil organic matter. Thereafter, oxides of Fe and Al were extracted using three different extractants: dithionite-citrate-bicarbonate (DCB) mixtures, acidified ammonium oxalate and sodium pyrophosphate solution. The quantification of Fe and Al oxides contents in the respective extracts were carried out using Inductively Coupled Plasma-Atomic Emission Spectrometry. The research findings indicated that the DCB extractable forms of Fe and Al oxides were more abundant compared to other forms of these oxides, and a substantial portion of these oxides within the soils existed in crystalline form. Among the soil series studied, Itagunmodi series exhibited the highest amount of DCB-and oxalate extractable Fe oxides, while Iwo series had the highest content of Fe and Al oxides extracted by sodium pyrophosphate solution. Importantly, the presence of Fe oxides were found to negatively impact the reactivity of SOM in the soils.

Soils derived from fine-grained biotite gneiss and schist are extensive in southwestern Nigeria and are reportedly suitable for both arable and tree crops. Pepper is an indispensable part of the daily diet of millions of Nigerians. However, its productivity in southwestern Nigeria is low compared with its’ demand. This study assessed the suitability of soils formed in fine-grained biotite gneiss and schist in rainforest area of southwestern Nigeria for pepper production. The selected toposequence was delineated into four physiographic units and soil profile pits were established, described and sampled at each unit. The soil samples collected were analyzed for particle size distribution, pH, salinity and organic carbon. Land characteristics obtained were matched with the crop requirements for pepper to obtain the soils’ suitability classes using parametric method. Results show that the soils were currently marginally suitable (S3) to not suitable (N) for pepper production. The major agronomic constraints of the soils in order of severity were climate (too high rainfall), fertility (high soil acidity) and topography (slope greater than 3%). It was therefore recommended that planting in areas with less amount of rainfall (750-900 mm) and effective agronomic practices will ensure sustainable pepper production.

Our previous studies showed that the extreme high yield tropical rice (Padi Panjang) produced 3-8 t ha-1 without fertilizers. We also found that the rice yield did not correlate with some soil properties. We thought that it may be due to ability of root in affecting soil properties in the root zone. Therefore, we studied the extent of rice root in affecting the chemical properties of soil solution surrounding the root zone. A homemade rhizobox (14x10x12 cm) was used in this experiment. The rhizobox was vertically segmented 2 cm interval using nylon cloth that could be penetrated neither root nor mycorrhiza, but, soil solution was freely passing the cloth. Three soils of different origins (Kuin, Bunipah and Guntung Papuyu) were used. The segment in the center was sown with 20 seeds of either Padi Panjang or IR64 rice varieties. After emerging, 10 seedlings were maintained for 5 weeks. At 4 weeks after sowing, some chemical properties of the soil solution were determined. These were ammonium (NH 4 +), nitrate (NO 3-), phosphorus (P) and iron (Fe 2+) concentrations and pH, electric conductivity (EC) and oxidation reduction potential (ORP). In general, the plant root changed solution chemical properties both in-and outside the soil rhizosphere. The patterns of changes were affected by the properties of soil origins. The release of exudates and change in ORP may have been responsible for the changes soil solution chemical properties.

Local rice varieties are commonly grown by the farmers located in acid sulfate soil area of South Kalimantan. In South Kalimantan, more than 100 local rice varieties can be found. In 1999, a farmer found one hill (with 5 tillers) rice plant near a canal, later called Padi Panjang. The rice had panicle length of 50 cm. The panicle length of common local rice varieties are 25 cm. Since the finding, the farmer multiplied the seed for 3 years to get a reasonable amount of seeds for nearby farmers to use. In 2004, there were 25 farmers grow the Padi Panjang by themselves. Their paddocks are widely spread out in Aluh-Aluh and Gambut districts. We take this opportunity to investigate yield variation of the Padi Panjang that may be affected by soil properties variability. Ten paddocks out of the 25 paddock were selected. At harvest time (in July-August), we measured the rice yield and collected soil sample from the 10 paddocks. We found that the soil condition in the selected paddocks were marginally suitable for growing improved rice. Without fertilizer, however, the rice yield varied from 3.21 to 8.09 Mg ha-1. We also observed that the rice yield variations associated with tillers number. We did not find any correlation between rice yields with some selected soil properties, except it was observed that the tillers number was negatively correlated with soil electrical conductivity (EC). The extreme yield of Padi Panjang might be explained the involvement of N fixing bacteria and P solubilizing bacteria, large rooting system and the ability of Padi Panjang root in modifying the rhizosphere soil.

A geoquímica de superfície aplicada à exploração de petróleo baseia-se na detecção e análise de exsudações de hidrocarbonetos em superfície ou próximo a ela. A interpretação dos dados obtidos depende do conhecimento sobre a origem do gás e como ele se relaciona com o meio amostrado. O objetivo deste trabalho é avaliar o comportamento de hidrocarbonetos leves, sob forma gasosa, induzidos em recipientes portadores de argilas com diferentes capacidades de adsorção e com isso, obter resultados para auxiliar na interpretação dos dados obtidos em geoquímica exploratória de superfície através de amostragem de materiais inconsolidados. A viabilidade para a pesquisa se deu por uma parceria entre a Petrobrás e UFRJ, através do Cenpes e do Departamento de Geologia. Para alcançar este objetivo é necessário cumprir algumas metas, que incluem: a adequação do laboratório de química dos solos do Departamento de Geologia da UFRJ para a realização dos experimentos, a confecção de um cilindro de vidro...

An investigation into the effects of cocoa bean husk (CBH) and NPK fertilizer on the chemical properties of soil and groundnut (Arachis hypogaea L.) performance was carried out at the Teaching and Research Farm of the Federal Polytechnic, Ile-Oluji, Ondo State, Nigeria. The experiment was designed using a randomized complete block design (RCBD), with each treatment replicated four times. The treatments tested were Control, 300 kg/ha NPK fertilizer (NPKF), 6 t/ha CBH, 4 t/ha CBH + 150 kg/ha NPK fertilizer, and 4 t/ha CBH + 100 kg/ha NPK fertilizer. The number of leaves, number of branches, and plant height recorded for 300 kg/ha NPKF, 4 t/ha CBH, and 150 kg/ha NPKF were not significantly different.

The objectives of the research were: (i) to isolate and characterize of phosphate solubilizing bacteria (PSB) and (ii) to identify PSB based on molecular amplification of 16S rRNA gene. Soil samples were collected from rhizosphere in Bogor, West Nusa Tenggara, and East Nusa Tenggara. Several stages in this research were: (i) isolation PSB in Pikovskaya agar, (ii) morphological and biochemical characterization of PSB, (iii) measurement of phosphatase enzymes, and (iv) measurement of secreting indole acetic acid phytohormone. As many as 29 isolates of PSB have been collected and three isolates of them, namely: P 3.5 (East Nusa Tenggara), P 6.2 (West Nusa Tenggara), and P 10.1 (Citeureup, West Java) were chosen for further study. There were many characteristics of isolate P 10.1: (i) it had capable to solubilize P with the value of highest solubilization index (1.80), (ii) it had the highest phosphatase enzyme (120.40 mg kg-1), and (iii) it had the highest pH decrease at each observation for six days. Isolates P 3.5 and P 10.1 were the Gram-negative bacteria with coccus shapes and isolate P 6.2 was a Gram-negative bacteria with bacillus shape. Deoxiribonucleat Acid (DNA) amplification of these bacteria employing 16S rRNA primers generated the 1,300bp-PCR product. The results of the analysis of 16S rRNA gene sequences showed that isolates P 3.5 and P 10.1 has 98% similarity with Gluconacetobacter sp. strains Rg1-MS-CO and isolate P 6.2 has 97% similarity with Enterobacter sp. pp9c strains.

Este trabalho teve por objetivo a conservação e revitalização do lago do Colégio Técnico da UFRRJ (CTUR) a partir da necessidade de aproveitamento das áreas produtivas e Recuperação das Áreas Degradadas (RAD), através do Sistema Agroflorestal (SAF). Dentro deste contexto foi pensado em um espaço de interação pedagógica com a finalidade de construção de conhecimentos práticos para os cursos técnicos em agroecologia e meio ambiente, agregando valor paisagístico ao espaço. Corroborando com o critério de sucessão, foram utilizadas espécies pioneiras antrópicas e secundárias-pioneiras antrópicas, e em seguida secundárias tardias e clímax. A execução do projeto ocorreu através de levantamento de literatura pertinente e mutirão agroecológico, contando com a colaboração dos estudantes, professores, pesquisadores e extensionistas, sendo de fundamental importância à participação de todos como principais agentes atuantes.Eje: B2 Paisajes, territorios y agroecología (Relatos de experiencias)Fac...

Bentonite-sand mixture is considered to be a potential liner material for landfill facilities owing to its excellent sorption potential and swelling characteristics. Such liner materials are expected to perform satisfactorily if the hydraulic conductivity is maintained less than 10 −7 cm/s and thereby inhibiting the migration of the generated leachate. However, the performance assessment of these liners in the presence of highly concentrated organic fluids and under the overburden stresses that is usually expected in landfill conditions is scarce. Therefore, in the present work, the hydraulic performance of the bentonite-sand mixtures in the presence of the organic compounds commonly encountered in the landfill leachate is studied, which is a need of the hour. Flow tests were performed to evaluate the hydraulic conductivity of different bentonite-sand mixtures in unhydrated conditions and permeated with varied proportions of methanol-water and ethanol-water mixtures. The study reveals that the proportions of the organic pore fluids significantly influence the hydraulic conductivity of the bentonite-sand mixtures. A very good linear relationship was observed between the pore fluids' dielectric constants and the hydraulic conductivity of the bentonite-sand mixtures. The chemomechanical behavior suggests that the conventional bentonite-sand mixtures perform poorly in terms of the hydraulic and swelling characteristics with the change in the dielectric constant of the organic fluids. The microstructural analysis also supports the experimental findings that as the dielectric constant of the fluid are reduced, the effective flow path through the soil increases considerably resulting in higher hydraulic conductivity.

The objective of this work was to determine the influence of eight rootstocks on the yield, fruit quality, and survival of 'Pêra CNPMF D6' sweet orange (Citrus sinensis) trees grown under rainfed conditions in a cohesive soil of the Brazilian Northeast. In 2014-2018, the yield, fruits, and survival of trees planted in 1997 were evaluated in a randomized complete block design. Yield was assessed using annual fruit production, yield efficiency, and the alternate bearing index. Tree survival was considered the percentage of plants that remained alive until 2018. Fruit quality was evaluated by physicochemical attributes. 'Cravo' confirmed its good yield performance. Despite the lower number of trees, the 'Mazoe' rough lemon rootstock induced the highest fruit yield. The 'Cravo' x 'Cleópatra' hybrid and 'Volkameriano' lemon favored the highest trees survival, whereas 'Indio' citrandarin and 'Cravo' lime resulted in intermediate levels. The 'San Diego' and 'Riverside' citrandarins induced shorter tree with a high yield efficiency and a higher alternate bearing index, respectively. Fruits with less juice and mass were induced, respectively, by 'Riverside' citrandarin and 'Volkameriano' lemon. It can be concluded that the 'Mazoe' rootstock induces a higher fruit yield and 'Cravo' x 'Cleópatra' and 'Volkameriano', a greater survival. In addition, all rootstocks, except 'Riverside' and 'Volkameriano', induce fruit that meet the minimum quality requirements.

The objective of this work was to determine the influence of eight rootstocks on the yield, fruit quality, and survival of 'Pêra CNPMF D6' sweet orange (Citrus sinensis) trees grown under rainfed conditions in a cohesive soil of the Brazilian Northeast. In 2014-2018, the yield, fruits, and survival of trees planted in 1997 were evaluated in a randomized complete block design. Yield was assessed using annual fruit production, yield efficiency, and the alternate bearing index. Tree survival was considered the percentage of plants that remained alive until 2018. Fruit quality was evaluated by physicochemical attributes. 'Cravo' confirmed its good yield performance. Despite the lower number of trees, the 'Mazoe' rough lemon rootstock induced the highest fruit yield. The 'Cravo' x 'Cleópatra' hybrid and 'Volkameriano' lemon favored the highest trees survival, whereas 'Indio' citrandarin and 'Cravo' lime resulted in intermediate levels. The 'San Diego' and 'Riverside' citrandarins induced shorter tree with a high yield efficiency and a higher alternate bearing index, respectively. Fruits with less juice and mass were induced, respectively, by 'Riverside' citrandarin and 'Volkameriano' lemon. It can be concluded that the 'Mazoe' rootstock induces a higher fruit yield and 'Cravo' x 'Cleópatra' and 'Volkameriano', a greater survival. In addition, all rootstocks, except 'Riverside' and 'Volkameriano', induce fruit that meet the minimum quality requirements.

The topographic position is among the factors influencing soil formation. This study aimed to characterize and classify the soils used for sugarcane plantation developed in different topographic position. This research was conducted in the sugarcane plantation area of Camming, District of Bone, South Sulawesi, Indonesia, from November 2017 to March 2018. Soil observation was carried out on 3 transects, where each transect consisted of three soil profiles located in different position namely summit, backslope, and valleys. Soil samples from each horizon were analyzed for their physical, chemical and micromorphology characteristics in the laboratory. The soil classification system was done by using soil taxonomy up to subgroups level. Results showed that soil characteristics, i.e. soil depth, cation exchange capacity, and the sum of basic cations were likely to increase in the valley than in the backslope and summit. The primary minerals, mainly quartz, calcite, biotite, opaque, and orthoclase, were found especially in the backslope and valley. The pore types consisted of vugh and packing void pores. Pedofeature type of soil was generally in the form of concretions and nodules that showed the process of oxidation and reduction. The soil type in the study area was classified into Typic Haplustepts and Typic Haplustalfs.

Contents 1. Introduction 2. Development of Variable Charge Properties 2.1 Soil Mineralogy 2.2 Soil Surface Charge 2.3 Adsorption Properties 2.4 Effect of Ionic Strength on Ion Adsorption 3. Electric Double Layer Interaction Between Oppositely Charged Particles 3.1 Binary Systems 3.2 Soil Systems 3.3 Effect on Desorption of Cations 3.4 Effect on Soil Acidification 4. Adsorption of Low-molecular-weight Organic Anions 4.1 Adsorption of Organic Anions 4.2 Surface Charge Reversal 4.3 Effect on Zeta Potential 4.4 Effect on Adsorption of Cations and Anions 4.5 Effect on Chemical Behaviors of Aluminum 5. Biochar-induced Changes of Surface Chemical Properties 5.

Soil chemical, physical and biological analyses are a crucial but often expensive and time-consuming step in the characterization of soils. Rapid and accurate predictions and relatively simple methods are ideally needed for soil analysis. The objective of this study was to predict some soil properties (e.g. pH, EC, total C, total N,C/N, NH 4-N, NO 3-N, P, K, clay, silt, and sand and soil microbial biomass carbon) across the Wickepin farm during summer season using a Mid-Infra Red-Partial Least Square (MIR-PLS) method. The 291 soil samples were analyzed both with soil extraction procedure and MIR Spectrometer. Calibrations were developed between MIR spectral data and the results of soil extraction procedures. Results using the PLS-MIR showed that MIR-predicted values were almost as highly correlated to the measured value obtained by the soil extraction method of total carbon, total nitrogen and soil pH. Values for EC, NH 4-N, NO 3-N, C/N, P, K, clay, silt, sand, and soil microbial biomass carbon were not successfully predicted by the MIR-PLS technique. There was a tendency for these factors to correlate with the MIR predicted value, but the correlation values were very low. This study has confirmed that the MIR-PLS method can be used to predict some soil properties based on calibrations of MIR values.

Soil fauna has played an important role in ecosystem functioning, especially as ecosystem engineers which contribute to soil fertility in tropical environment. A tailing deposition area is one habitat that has several types of soil fauna to live and growth as well as involves in the decomposition of organic matter. The objective of this study was to examine the number and distribution of soil fauna in the tailing area of Freeport Indonesia Mining and Gold Company, Timika. The study was located in some inactive tailing deposition areas in between Double Levee of the lowland area of ModADA (Modification Ajkwa Deposition Areas). Samples were taken from inactive tailing as 198 of ModADA for soil and soil fauna, the Kuadran Method was used to collecting soil fauna on the soil surface and in the soil. There were 17 types/ordo of soil fauna in the study area and the highest number was a group of ants (Hymenoptera/Formicidae). Population density (PD) and relative density (RD) of soil fauna (Formicidae) ranged from 0.03-2.41 Individu m-2 (PD) and 0.07-6.50% (RD). Both PD and RD were likely to increase as the number of soil fauna increase. The distribution of most soil fauna were found as a clump, while Pulmonata (Gastropods) were distributed normally in the tailing areas. The number and types (ordo) of these soil fauna had showed that inactive tailing deposition areas were considered a good habitat for soil fauna.

Soil chemical, physical and biological analyses are a crucial but often expensive and time-consuming step in the characterization of soils. Rapid and accurate predictions and relatively simple methods are ideally needed for soil analysis. The objective of this study was to predict some soil properties (e.g. pH, EC, total C, total N,C/N, NH 4-N, NO 3-N, P, K, clay, silt, and sand and soil microbial biomass carbon) across the Wickepin farm during summer season using a Mid-Infra Red-Partial Least Square (MIR-PLS) method. The 291 soil samples were analyzed both with soil extraction procedure and MIR Spectrometer. Calibrations were developed between MIR spectral data and the results of soil extraction procedures. Results using the PLS-MIR showed that MIR-predicted values were almost as highly correlated to the measured value obtained by the soil extraction method of total carbon, total nitrogen and soil pH. Values for EC, NH 4-N, NO 3-N, C/N, P, K, clay, silt, sand, and soil microbial biomass carbon were not successfully predicted by the MIR-PLS technique. There was a tendency for these factors to correlate with the MIR predicted value, but the correlation values were very low. This study has confirmed that the MIR-PLS method can be used to predict some soil properties based on calibrations of MIR values.

Rambutan (Nephelium lappaceum) is Sapindaceae family, commonly found in agroforestry land, owned by the community in Langkat District, North Sumatra Province as One of Multy Purpose Tree Species. This study aimed to asses and map the distribution land suitability for N. lappaceum. This research was conducted in Gunung Ambat Village and Simpang Kuta Buluh Village, Sei Bingai Sub District, Langkat Regency using survey method. The soil samples data was collected in the field based on the land unit. Land suitability assessment was evaluated using matching method. To map the distribution of land suitability, the Geographic Information System (GIS) was used. Global Positioning System (GPS) also was used in this study to record the coordinate points of each soil sample from the field. The results indicate that the actual land suitability classes for N. lappaceum were dominated by moderately suitable (S2) (97.56%) in Gunung Ambat Village and moderately suitable (S2) (52.92%) in Simpang Kuta...

Local farmers in South Kalimantan (Banjarese farmers) use to grow local rice cultivars. The local rice growing areas are varied with distance from the coastal line. Consequently, the degree of salinity also varied. To overcome the salinity problem, farmers do their last transplanting earlier than the farmers in the inland area and grow the local rice cultivars that they believe tolerant to salinity. In this study, we investigate the local rice cultivars grown by the farmers in the coastal areas. Sixty paddocks were selected in Pulantan, Aluh-Aluh, Simpang Warga and Bunipah Villages, Aluh-Aluh District, Banjar Regency, South Kalimantan. The rice yield of each paddock was estimated by sampling 3 x 5 hills in 3 replicates. The soil was collected within the 3 x 5 hills area and analysed their electric conductivity (EC) and pH. We found that there were four families of local rice cultivars grown, namely, Palas, Bayar, Pandak and Siam families. Among all local rice cultivars grown, it was...

This study aimed to evaluate the initial growth of aroeira in Oxisol soil with the addition of different organic (humus and vermicompost) and organic/mineral substrates (commercial substrate) and rock powder. Seeds were collected and, after germination, transplanted to different types of substrate. The treatments assembled, with different proportions of compounds, were: T1 (50% humus + 50% Oxisol); T2 (50% commercial substrate + 50% Oxisol); T3 (50% vermicompost + 50% Oxisol); T4 (40% humus + 40% Oxisol + 20% rock powder); T5 (40% commercial substrate + 40% Oxisol + 20% rock powder); T6 (40% vermicompost + 40% Oxisol + 20% rock powder); T7 (30% humus + 30% Oxisol + 40% rock powder); T8 (30% commercial substrate + 30% Oxisol + 40% rock powder); and T9 (30% vermicompost + 30% Oxisol + 40% rock powder). Initial plant development was influenced by the treatments; 20% powder and 40% nitrogen from humus (T4) produced seedlings with the greatest root, aerial part and total weight, in addit...

Limited databases on water retention and availability in soils to generate pedotransfer functions are available for tropical and subtropical soils. The objectives of the study were to generate and evaluate pedotransfer functions for soil water retention in soils from subtropical Brazil; and to estimate plant available water based on soil particle size distribution. Two databases were set up for soil properties including water retention: one had 725 data and the other 253 data. From the literature database, pedotransfer functions were generated, nine pedofunctions available in the literature were evaluated and the plant available water capacity was calculated. Pedotransfer functions for selected sections generated for the soils had coefficients of determination ranging from 0.56 to 0.66. Pedotransfer functions generated with soils from other regions were not appropriate for estimating the water retention. Plant available water content varied with soil texture class, from 0.089 kg kg-...

Background: Though soils in the study areas are characterized by higher iron and aluminum oxides, and low available P contents, study on P adsorption characteristics is limited. The purpose of this experiment was to evaluate adsorption properties of selected soils and determine the standard phosphorous requirements of the soils. In this experiment, separately weighed 2 g soil samples were equilibrated in 50 ml of 0.01 M CaCl 2 solution containing KH 2 PO 4 at rates of 0, 1, 2.0, 4.0, 8.0, 16.0, 24.0, and 32.0 mg P L −1. Results: The Freundlich model was found to be the best model for the description of the P adsorption characteristics of the soils. The Freundlich coefficient K f ranged from 123.32 to 315.31 mg P kg −1. The Goha-1 soil had the highest K f (315.31 mg P kg −1) as Ketasire had lowest K f (123.32 mg P kg −1) values. The value of SPR f was ranged from 50.50 to 154.02 mg P kg −1 for soils of the study area. Highly significant (P ≤ 0.01) correlation was observed between the Freundlich adsorption parameters and soil physicochemical properties. Conclusion: The standard P requirement of the studied soils was higher than the blanket P fertilizer rate recommendations in Ethiopia. Lack of inadequate knowledge about internal and external P requirement of each crop might have decreased yield in the study areas as it could have resulted in under-application of fertilizer P. The presence of high correlation between the adsorption parameters and the soil properties suggested the indices' prominent role in explaining P adsorption characteristics of the soils. Since higher dose of P is required by soils in the study area because of fixation, alternative P management strategies is needed to reduce P adsorption and enhance P availability.

It is generally known that zeolite has potential for heavy metal adsorption. The  objectives of this study were to synthesize and characterize zeolite ZSM-5 and to figure out the adsorption capacity of zeolite ZSM-5 for heavy metals of Cu2+, Pb2+ and Cd2+. Characterization of zeolite ZSM-5 included some variables i.e. crystal structure (XRD), morphology (SEM), specific surface area and total pore volume (N2 physisorption). Adsorption capacity of zeolite ZSM-5 was analysed using a batch system with heavy metals of Cu2+, Pb2+ and Cd2+ in various concentrations (50, 100, 150, 200 and 250 ppm) with contact times 30, 60, 90, 120 and 250 minutes. Adsorption data was calculated by Langmuir and Freundlich isotherm. The results showed that the maximum adsorption capacity of zeolite ZSM-5 against heavy metals of Pb2+, Cu2+, and Cd2+, were 74.07, 69.93 and 60.24 mg g-1, respectively. These indicated that synthetic zeolite ZSM-5 had potential to adsorb heavy metals. The results also suggested t...

The amazon soil degradation has been intensified by the increase of the many uses of the soil and by the necessity of improvement on commodities production. This context points to the emerging necessity of sustainable ways of production. The objective of this research was to evaluate the agroforestry system potential (AF's) about the environmental liability of nutrient loss for erosion and reposition cost in comparison with monocultures (black pepper and palm oil), pastures and forest reservation on a rural property of a Mixed Agricultural Cooperative of Tomé-açu (CAMTA), Pará state. The soil loss were calculated using the universal equation of soil loss through aerial survey with drone, and the costs of reposition respected, not even the soi loss, but the concentration of K, Ca, Mg, P and N in the soil samples collected in the different uses of the area. The results showed that the AF's presented less of soil loss and, consequently, minor spending with nutrient reposition. The soil loss in the monocultures of black pepper resulted in reposition costs almost seven times higher than the AF's costs. The costs with pasture and oil palm were three and a half and two times higher than the AF's, respectively. It can be concluded that the AF's are more efficient in relation to the retention potential of nutrients in the soil through the reduction of its loss for erosion and the improvements in the productivity associated with the reduction in spends with fertilizers.

Lettuce (Lactuca sativa) is vegetable crop that consumed part of the leaf and harvested at a phase of vegetative. Nitrogen play important role in growth at phase of vegetative. Nitrogen in spacious have the character of easy to lose because of leaching. Increasing yield of lettuce can be done byimproving Nitrogen synchronization, that is precisely usage moment with ready moment of N during and amount of its. The research was aimed to study of the pattern nitrogen requirement for lettuce crop, ready pattern of nitrogen by Tithonia diversifolia and design nitrogen synchronization model between lettuce crop with green manure of T. diversifolia. The research were divided in two phases that are phase research 1: Dynamic modeling for nitrogen synchronization on lettuce cultivation by green manure of T. diversifolia, and phase research 2: Fertilizer technology of high nitrogen synchronization on lettuce cultivation by green manure of T. diversifolia. The result of phase research 1 (first y...

The higher national rice demand encourages various efforts to increase rice production. This increase in rice production occurs in line with increasing public awareness of healthy foods, especially organic rice. Rice field management with an organic system is expected to provide a higher yield and quality of rice. This study aims to determine the effect of the long-time application of an organic rice management system on rice yield and quality. Descriptive exploratory research is supported by laboratory analysis of samples of organic rice plants with three periods (10 years, 7 years, and 4 years), semi-organic and conventional. The parameters observed were dry harvested grain, dry milled grain, the weight of 1000 grains, unfilled grain, protein content, amylum, amylopectin, and reducing sugar. The most prolonged organic rice field management with the application of 10 years gives better results with a protein content of 6.14%, amylum 71.71%, and amylopectin 49.35%. While the application of organic farming for 7 years gives the highest rice yield, the difference is not confirmed with the application of organic 10 years, with the weight of dry grain harvest 10.44 Mg ha-1 , dry milled grain 8.15 10.44 Mg ha-1 , the weight of 1000 grains 24 g, and unfilled grain 3.8%.

Rice is one of the staple crops in Burkina Faso. However, the local production covers only 47% of the population demands. One of the main reasons of the poor productivity in Burkina Faso is iron toxicity which is related mainly to the activity of Iron Reducing Bacteria in the rice field's ecosystems. In order to control the harmful effects of Iron Reducing Bacterial populations and to improve rice productivity, a pots experiment was conducted at the experimental site of the University Ouaga I Pr. Joseph KI-ZERBO. An iron toxic soil from Kou Valley (West of Burkina Faso) and two rice varieties, BOUAKE-189 and ROK-5, sensitive and tolerant to iron toxicity, respectively, were used for the experiment. The pots were drained for 14 days (D2) and amended with chemical fertilizers (NPK + Urea and NPK + Urea + Ca + Mg + Zn complexes). Control pots without drainage and fertilization (D0/NF) were prepared similarly. The kinetics of Iron Reducing Bacterial populations and ferrous iron content in soil near rice roots were monitored throughout the cultural cycle using MPN How to cite this paper: Otoidobiga, C.H.,

Variation in diversity of fungi isolated from soil was studied in a ferrallitic and a hydromorphic soil, in an experimental area of the Tai National Park (SW Ivory Coast). Several experimental disturbances were produced, and the change in species diversity was observed both within and between years, over seven years. The disturbances, as well as the changes in soil moisture produced by variation of rainfall, act as extrinsic factors to the community, influencing the level of diversity. The variation of diversity within the community in time, however, seems to occur as an internal mechanism. Species with a generalist or specialist behavior were identified, in accordance with their occurrence in dry and wet periods. Two new species and two new genera found here do not seem to be rare or have limited distributions, but rather appear as generalists. Knowledge of the fungi isolated from soil is of considerable interest in tropical forests, where traditional shifting cultivation is practiced. Cultivation is currently considered responsible for ecosystem degradation. This paper, however, shows that traditional cultivation, when practiced as a short time-space disturbance, does not appear to cause serious disturbance to the fungal diversity.

Crop salt tolerance is generally assessed as the relative yield response to the increasing of root zone salinity. This paper studied the maize tolerance under salinine water (ECw) and their relationship with the changes of soil chemistry characteristics, crop growth and yield of maize. The seven level of water salinity were 0.66, 0.93, 1.57, 1.68, 2.46, 3.35, 3.85 mS cm-1 and three local maize from Madura, Pasuruan and Probolinggo were evaluated to soil electric conductivity (ECe), pH, available-N.-P. and-K as well as plant height and seed weight The experiment indicated that saline water (ECw) up to a certain concentration increased soil salinity (ECe) and pH, but decreased nutrient availability, plant height, fresh and dry weight of maizes. ECw level between 1.5 to 1.7 mS cm-1 gave the best results compared to others, because of soil nutrients and water availability optimum. Maize of Madura and Pasuruan were more tolerant than Probolinggo giving ECw up to 3. 85 mS cm-1 , although their maize seed dry weight were lower.