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Eucalyptus (Eucalyptus spp.) leads to depletion of nutrients from the soil due to its fast growing nature. Therefore, a pot experiment was conducted to study the effect of zinc (Zn) application on clonal eucalyptus growth, biomass output and its uptake, as well as response of eucalyptus to Zn in soils of three textures. The treatments consisted of eight levels of Zn (0, 5, 10, 15, 20, 25, 30, and 35 mg kg−1 applied through ZnSO4.H2O) in a completely randomized design triplicated in soils of three distinct textures (loamy sand, sandy loam and sandy clay). The plant height, collar diameter, dry weight of shoot and roots, soil plant analysis development (SPAD) readings, Zn concentration and uptake by leaves, stem+branches and roots increased significantly with Zn application. Average dry weight of shoot and roots (31.93 and 15.12 g plant−1, respectively) was significantly highest at 15 mg Zn kg−1 whereas Zn concentration and uptake (18.35 mg kg−1 and 286.2 µg plant−1, respectively) by roots were highest at 20 mg Zn kg−1. The above parameters differed significantly among soils as sandy clay>sandy loam>loamy sand except Zn content and uptake by roots and SPAD values which were highest in sandy loam soil. Loamy sand and sandy loam soil exhibited higher Zn use efficiency, shoot biomass response and uptake response to applied Zn than sandy clay soil. It is concluded to apply 20 mg Zn kg−1 in light soil and 15 mg Zn kg−1 in heavy textured soil for better growth and productivity of eucalyptus. [ABSTRACT FROM AUTHOR]

The agricultural frontier in Brazil advances mainly in areas of sandy soils, where the management of soil fertility is still a challenge, including the practice of liming. Limestone dissolution was investigated under varying doses (0–40 t ha−1) in soil samples with a wide range of textural gradients (5%–74% clay). In view of textural variations and limestone rates, the objective was to generate information regarding pH, the residual liming effect, and exchangeable calcium (Ca) and magnesium (Mg) levels, including under overliming conditions. Throughout the textural gradient, the pH was between 4.2 and 8.5. On more sandy soils (5%–18% clay), overheating (pH > 7) was obtained with ~ 2 t ha−1 of limestone. On clayey soils (37%–74% clay), a similar effect was obtained with ~ 10 t ha−1 of limestone, indicating the marked difference in the acid buffering capacity of these soils. In addition, the equilibrium pH in the context of overliming in sandy soil was higher (8.2) compared with clayey soils (7.8). The residual liming effect was greater in sandy soils due to the lower potential acidity. Regardless of the soil texture, the Ca/Mg ratio increased in the context of overliming. Liming must be carefully applied and requires proper recommendations, especially on sandy soils, avoiding pH ≥ 6.5, a condition that is not suitable for most crops. [ABSTRACT FROM AUTHOR]

The effect of amending "barren" sandy and clay soils with different organic origins on soil organic carbon (SOC) accumulation and permeability is not well known. Therefore, proposing desirable practices to improve their qualities and fertility is a major challenge. To improve soil organic carbon, permeability (PR) and productivity, the two barren soil textures were amended with 0.39 and 0.78 tha−1 (ton per hectare) of manure and lignite, respectively, and irrigated with treated wastewater. During the four years of experimentation, the ranges of increase in SOC of sandy and clay soils were 1.9–3.87 kgm−2, and 0.29–1.40 kgm−2, respectively, and in PR of 35.2–69.3% in sandy soils and 39.3–74.8% in clay soils. These improvements have a major effect on nutrient cycling, significantly improving water and nutrient availability to roots and plants. The levels of improvement increase with the amounts of organic compounds introduced, especially in the clay soil amended with 0.78 tha−1. The proportions of mineralized (lost) SOC were 35.3–62.3% in the sandy soils and 1.0–3.1% in the clay soils. The maximum crop weights produced were approximately 41.2 gm−2 in sandy soils and 1152 gm−2 in clay soils. Thus, amendment of barren sandy and clay soils by all three sources of organic carbon was beneficial, especially for the clay soil. achieved the desired objectives. The gain in clay soils is significantly greater than in sandy soils, which require further study. The type of practice desired by farmers will depend on cost and crop yield. Laboratoire Géoressources. Univerversité de Carthage-Centre des Recherches et Technologies des Eaux, B.P. 273, Soliman 8020 (Tunisia). [ABSTRACT FROM AUTHOR]

Bioremediation has been proven to be efficient method of cleaning up oil contaminated soils through the application of proper microorganism to contaminated soils. Hence, this research involves the bioremediation of four different types of contaminated soil. The soils were categorized as laterite, sandy soil, clay soil, and loamy soil which are classified technically using American Society for Testing and Materials (ASTM) method as clayey sand, silty sand, clayey sand and poorly graded sand respectively. These soils were contaminated with Bonny light crude oil to the concentration of 33.3 g/l. The soils were inoculated with petroleum remediation microorganisms. Soil samples were taken after 14 and 25 days, and the residual total petroleum hydrocarbon (TPH) was checked using Environmental Protection Agency (EPA) Method 8015. The condition of the soils was kept almost constant during the process by preserving it in an insulated vessel to avoid evaporation of moist or organic gases. The results obtained showed percentage reduction 70%, 69%, 49%, and 26% in hydrocarbon after the period of 25 days in Sand, Laterite, Topsoil and Clay soil respectively. The removal percentage was the highest (70%) for the sandy soil, and the lowest for the clay soil (26%). The result indicate that the particle size distribution of soil affects bioremediation to an extent, since clay with lowest particle size proved more difficult to bio-remediate. [ABSTRACT FROM AUTHOR]

Co-application of fertilisers and biofertilisers increases solubility and concentration of nutrient elements in the soil. However, information on the effect of P fertiliser and rhizobium inoculation on the concentration of mineral elements in the rhizosphere of field-grown chickpea in contrasting soil types is lacking. We assessed the effect of phosphorus fertiliser, rhizobium inoculation, and rhizobium inoculation plus P fertilizer on the concentration of nutrients in the rhizosphere of 2 chickpea genotypes (ACC#1 & ACC#5) at clay and sandy soil sites in two consecutive years. ACC#5 accumulated higher amounts of rhizospheric nutrients than ACC#1 in both soil types despite the variable response to fertiliser treatment. Rhizobium inoculation plus P fertiliser resulted in higher accumulations of rhizosphere N (7-219%), P (20-348%), K (9-365%), Ca (2-155%) and Zn (15-259%) compared to the other fertiliser treatments suggesting an additive effect of P fertiliser and rhizobium inoculation. Moreover, the effect of fertiliser treatments was more pronounced in the clay than the sandy soil. Our investigation is the first to document the effects of fertiliser treatment, genotype, and soil type on the accumulation of rhizosphere nutrients in field-grown chickpea. However, we propose further studies, incorporating more cultivars and environments, before making practical recommendations. [ABSTRACT FROM AUTHOR]

Owing to their specific sedimentary or weathering formation history, most soils confronted in civil engineering can be categorised into clayey and sandy soils. In view of the great mechanical difference, particularly the distinct liquefaction resistance, then precisely simulate the mechanical and liquefaction characteristics of different type soils become an important research issue in seismic design of civil engineering structures. Considering soil turns into overconsolidated state once experiences stress unloading, and which affects the mechanical and liquefaction characteristics in turn. Based on the classical Cam-clay model, with the introducing of subloading surface concept, the subloading surface Cam-clay model provide an unified constitutive model in the numerical simulation of different type soils. Based on the comprehensive parametric studies of state variables evolution and anti-liquefaction capability of soil conducted in this paper, we creatively unified the relationship between OCR and relative density of soil that widely adopted in the liquefaction resistance evaluation of sandy soil, and our test results shows high correlation between these two parameters. These findings provide a solid theoretic support and guidance for the dynamic compaction method that widely adopted in anti-liquefaction design. [ABSTRACT FROM AUTHOR]

Soil hydraulic properties are the key indicators that govern soil functioning. However, sandy and clay soils that cover large areas in semi-arid climate regions have inadequate hydraulic properties for agricultural activities. Therefore, their managements are necessary to help in sustaining agricultural production at acceptable levels. The impact of amendments of these two soil textures with 0.39 t.ha−1 (ton per hectare) and 0.78 t.ha−1 of zeolite and manure and 0.78 t.ha−1 of lignite and irrigated with treated wastewater (TWW) on soil hydraulic properties and roots/crops ratios were investigated. TWW and inputted zeolite, manure and lignite have moderately declined hydraulic conductivities (Kf), and increased bulk densities (BD) and water retention capacities (Wr %) of sandy soils. While in clay soils, an increase of Kf and BD and Wr decreases were observed after addition of manure and lignite. Zeolite addition again decreased Kf. The soil hydraulic property improvements were proportional to the used quantities. The statistical analyses showed that there was a statistically significance for the bulk density indicating a strong interaction between the soil textures and the different amendments. The hydraulic property improvements increased agricultural soil productivities of clay soils. The highest obtained weight crop/root volume ratio was from amended clay soils with manure. The new sandy soil properties remained unfavorable for agricultural activities, except the soil amended with lignite. In the long term, to have a better economic profitability of amended clay soil, the use of 0.78 t.ha−1 of zeolite or lignite is more advisable because they remain longer than manure. [ABSTRACT FROM AUTHOR]

Foliar sprays with micronutrients are widely employed in agricultural production as an alternative to improve soil fertilization and plant nutritional status. We hypothesized that less water-soluble sources of manganese (Mn; MnCO3) could serve as a slow-release source compared to a water-soluble source (MnSO4.H2O). Our goal here was to evaluate Mn-sources (MnSO4.H2O and MnCO3) and rates (150; 250; 350; and 450 g ha−1) sprayed in the 3rd and 4th trifoliate leaflets of soybean growing in clayey and sandy soil under controled conditions. In phenological stages V7 (vegetative period) and R1 (reproductive period), dry matter, height, the diameter of the stem, and Mn-content in the shoot, stem, and in the trifoliate leaflets were determined. Results showed that the application of Mn resulted in an augmented Mn-content in the 3rd and 4th trifoliate leaflets (sandy) and the 3rd and 5th trifoliate (clayey). The MnSO4.H2O promoted Mn-retranslocation from the 3rd/4th trifoliate to the stem and the 5th/6th trifoliate. However, MnCO3 was accumulated in the 3rd/4th trifoliate. The Mn-rates presented a linear response in sandy soil and quadratic response in clayey soil. Clayey soil was characterized by the higher Mn-contents in the stem, while sandy soil presented the higher Mn-contents in the 3rd, 4th, 5th, and 6th trifoliate. Our results suggest that MnSO4.H2O is more effective in increasing Mn-content in soybean leaves during plant development due to the Mn-retranslocation to sink organs (5th/6th trifoliate leaflets and shoot). [ABSTRACT FROM AUTHOR]

Microbially induced calcium carbonate precipitation (MICP) method can convert heavy metals from mobile forms into more stable crystals. This study was conducted to investigate the removal of cadmium (Cd) by Sporosarcina pasteurii through the urea hydrolysis pathway. Cd removal from solution containing 0.5, 1, and 2 mmol l−1 of Cd (as CdCl2.5H2O) were measured firstly, and then the amount of Cd removal was studied in two sandy and clay soils containing 10, 20, 40, and 50 mg kg−1 of Cd. The experiments were arranged in complete randomized design with three replications. Minimum inhibitory concentration (MIC) of Cd for bacteria growth was attained as 2 mmol l−1, after 48 h of incubation. Cd removal efficacy was 99.6% in 0.5 mmol l−1 and 99.8% in 1 and 2 mmol l−1 Cd solutions. In both soils that were inoculated with bacteria, Cd concentration decreased in solution-exchangeable fraction significantly (p ≤ 0.05). The Cd concentration in the solution-exchangeable fraction of sandy and clay soils were decreased to 85.9, 61.1, 74.3, 80.3% and 89.3, 86.6, 76, 75.6% of its initial values (i.e., 10, 20, 40, and 50 mg kg−1), respectively. The amount of Cd in carbonate fraction in both sandy and clay soil increased significantly in the presence of bacteria (p ≤ 0.05). The results revealed that MICP-based removal of heavy metals via co-precipitation with calcite not only immobilized Cd in studied soils but also improved the microbial and enzymatic activities. [ABSTRACT FROM AUTHOR]

Brazil is an importer of fertilizers and the use of alternative sources is increasing in agriculture. The objective of this study was to evaluate the effect of Dunite rates on magnesium (Mg), silicium (Si), reducing sugars, sucrose and foliar starch, soil chemical attributes and soybean yield [Glycine max (L.) Merril] in two soil types. The treatments consisted in the five Dunite rates (0, 42, 208, 542, and 1542 mg kg−1) in a clayey soil, and five Dunite rates (0, 150, 238, 411, and 933 mg kg−1) in a sandy soil. In both crops and soils, the Mg and Si contents, reducing sugars and foliar glucose, as well as pH, Mg and Si of the soil, and yield components showed a positive response due to the increase of input rates. The Mg nutrition provides lower foliar starch levels, consequently, the best partition of metabolites to plant leads to better development, filling and yield of soybeans. [ABSTRACT FROM AUTHOR]

Soil boron (B) supply is usually used by farmers to correct B deficiency in many crops. The excessive application of this fertilizer may threaten environment components particularly underground water and soil. This study was undertaken to evaluate B migration at different soil characteristics and leaching levels. Three soils were collected from different southwestern Mediterranean areas. Then, three annual leaching rates were tested for each soil: 35 mm, 237 mm, and 565 mm in a sandy soil; 35 mm, 103 mm, and 247 mm in a silty-clay soil; 35 mm, 70 mm, and 140 mm in a clay-calcareous soil. The experiments were conducted in PVC columns filled with 30 cm of the studied soils. 0.5 mg kg−1 of B was applied to the surface of each soil. The results showed that B migration is mainly related to leaching rate and clay content. The soil B losses (y) can be predicted using the regression model: y (mg kg−1) = 0.001a–0.01b+0.14 (adjusted R2 = 0.92) where a = leaching rates (mm) and b = soil clay content (%). The B leaching threat is higher on sandy soil compared to other soils. However, soil B accumulation risk seems to occur particularly in silty-clay and clay-calcareous soils. Further, bioavailable B enrichment was recorded only on silty-clay soil. [ABSTRACT FROM AUTHOR]

After application, herbicides often reach the soil and affect non-target soil microorganisms, decreasing their population, diversity or affecting metabolic activity. Therefore, laboratory studies were performed to evaluate the effects of diuron, hexazinone and sulfometuron-methyl alone and mixed upon carbon transformation by soil microorganisms in clayey and sandy soils and the effect on bacterial diversity and structure. Control treatment without herbicide application was also performed. Sub-samples from the control and herbicide treatments (10 g – in triplicate) were collected before herbicide application and 7, 14, 28 and 42 days after treatment (DAT), then 1 mL of 14C-glucose solution was applied. The released 14CO2 was trapped in 2 M NaOH solution and the radioactivity was analyzed by liquid scintillation counting (LSC), 12 h after glucose application. The effect of herbicides on bacterial diversity was evaluated by T-RFLP. The experiment was conducted in a complete randomized design. Hexazinone did not affect 14CO2 evolution. Diuron showed a greater 14CO2 evolution in sandy and clayey soil, while sulfometuron-methyl led to an increase in sandy soil, at 42 DAT. A greater evolution of carbon was observed in the treatment with herbicide mixture in sandy soil, compared with the same treatment in clayey soil or control. However, the herbicide mixture application did not affect the soil biological activity measured by the respiration rate induced by substrate. On the other hand, the herbicide mixtures affected the bacterial diversity in both soils, being the strongest effect to diuron and sulfometuron-methyl in clayey soil and hexazinone in sandy soil. [ABSTRACT FROM AUTHOR]

GHGs production and emission may vary depending on soil physical properties, water management and fertilization. Two paddy soils characterized by different texture were incubated to evaluate the impact of flooding (permanent or intermittent) and N addition on potential N2O, CH4 and CO2 production and release into atmosphere and soil solution. Relationships with volumetric water content (VWC) and water filled pore space (WFPS) were evaluated. Overall, the finer clayey soil (CL) produced 58% more CH4 than the coarser sandy soil (SA) and showed an earlier sink to source transition; the difference was lower with N addition. Permanent flooding favoured the amount of dissolved CH4. SA produced more N2O emissions than CL under permanent flooding (31.0 vs. 3.7%); an opposite pattern was observed for dissolved N2O (16.4 vs. 52.7%). Fertilization increased N2O emissions under dry conditions in CL and under flooding in SA.Our findings showed that i) VWC had a larger influence on N2O and CH4 emissions than WFPS, ii) soil type influenced the gas release into atmosphere or soil solution and the timing of sink to source transition in CH4 emissions. Further investigation on timing of fertilization and drainage are needed to improve climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

Leaching of nutrients, particularly in sandy soil with low nutrient and water holding capacity (WHC), is a major threat to marine and fresh water pollution. Addition of clay soil to sandy soil could be an option to increase water and nutrient holding capacity of sandy soils, but the effect of clay soil addition may depend on the form in which the clay soil is added and the addition rate. Clay soil was added to sandy soil at rate of 10 or 20% (w/w) finely ground (<2 mm) or 2 and 5 mm peds with and without nitrogen (N) and phosphorus (P) fertilizer equivalent to 60 kg N ha−1and 15 kg P ha−1. The clay sand mixture for each treatment was weighed (30 g) in cores with nylon mesh at the bottom. The soils were incubated at 80% WHC for 7 weeks. To obtain leachate, 20 mL reverse osmosis (RO) water was added every week to each core. Leachate was analysed for inorganic N, P, and pH. Soil was analyzed for N, P, and pH before and after the leaching. Clay addition significantly reduced the leaching of N and P compared to sandy soil alone, with greatest reduction by finely ground clay soil and least with 5 mm peds. Compared to sandy soil alone, 83% more N was retained in clay-amended soil and P retention was doubled. This study showed that addition of finely ground clay soil can substantially reduce N and P leaching and thereby increase fertilizer retention compared to sandy soil alone. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the sorption-desorption and leaching of aminocyclopyrachlor from three Brazilian soils. The sorption-desorption of 14C-aminocyclopyrachlor was evaluated using the batch method and leaching was assessed in glass columns. The Freundlich model showed an adequate fit for the sorption-desorption of aminocyclopyrachlor. The Freundlich sorption coefficient [Kf (sorption)] ranged from 0.37 to 1.34 mmol (1-1/n) L1/n kg-1 and showed a significant positive correlation with the clay content of the soil, while the Kf (desorption) ranged from 3.62 to 5.36 mmol (1-1/n) L1/n kg¡1. The Kf (desorption) values were higher than their respective Kf (sorption), indicating that aminocyclopyrachlor sorption is reversible, and the fate of this herbicide in the environment can be affected by leaching. Aminocyclopyrachlor was detected at all depths (0-30 cm) in all the studied soils, where leaching was influenced by soil texture. The total herbicide leaching from the sandy clay and clay soils was <0.06%, whereas, ~3% leached from the loamy sand soil. The results suggest that aminocyclopyrachlor has a high potential of leaching, based on its low sorption and high desorption capacities. Therefore, this herbicide can easily contaminate underground water resources. [ABSTRACT FROM AUTHOR]

Seven grassland experiments on sandy and clay soils were performed during a period of 4 years to estimate the nitrogen (N) fertilizer replacement value (NFRV) of concentrated liquid fractions of separated pig slurry (mineral concentrate: MC). The risk of nitrate leaching when applying MC was compared to when applying mineral fertilizers. Grassland yields in 2009–2012 fertilized with MC were compared with grassland fertilized with two mineral fertilizers: granulated calcium ammonium nitrate and liquid ammonium nitrate (LAN). The mineral fertilizers comprised 50% nitrate-N and 50% ammonium-N, and MC comprised 95–100% ammonium-N. Treatment application rates included zero N and three incremental rates of N fertilization. The liquid fertilizers were shallow injected (0–5 cm). The NFRV of MCs was 75% on sandy and 58% on clay soil with granulated ammonium nitrate as reference, and 89% on sandy and 92% on clay soil with LAN as reference. Risk of nitrate leaching after application of MC, measured in residual soil mineral N post-growing season and N in the upper groundwater in the following spring, was equal to that for mineral fertilizers. [ABSTRACT FROM PUBLISHER]

Silt is available in many parts of the world in combination with sands and clays. However, due to lack of clear understanding of its engineering behaviour, most of the time it is interpreted in terms of either sands or clays. Structures that are usually built on silty soils are designed to take into account design procedures developed for sandy or clayey soils. Presence of silts in combination with varying amount of sand and clays produces silt that is either plastic or non-plastic in nature. Silt is available in and around the Delhi region, in a majority mixture along with fine sands, which is non-plastic in nature. On the other hand silty deposits found in offshore Bombay High region are found in abundance along with significant amounts of clays and are termed as plastic silts. In this paper a comparison of the stress-strain behaviour of plastic and non-plastic silts is carried out under triaxial compression loading during both drained and undrained conditions. Two representative samples each from Delhi and Bombay High regions were considered for this comparison and results of stress-strain under four sets of confining pressure are discussed in detail. It is observed from this study that behaviour of silts is mainly dependent on the composition and structure of the resultant soil matrix. It is concluded from the results that shear strength parameters as well as volume change/pore pressure response of silty soils is dominated by the constituent soil present along with the silt. It is seen from the comparative behaviour of non-plastic and plastic silts that the presence of sand and clays has a governing effect on pore pressure development and the resultant friction angle. The study also corroborated that the nature of silt is transitional both in the case of plastic and non-plastic forms. [ABSTRACT FROM PUBLISHER]

Salt accumulation has a negative effect on microorganisms, but plant residues may enhance the microbial activity and biomass. An experiment was conducted over 50 days to evaluate the effect of wheat and alfalfa residues on microbial activity and biomass and nitrogen (N) and phosphorus (P) availability in sandy and clayey soils at different salinity levels. Equivalent amounts of calcium (Ca+2) and sodium (Na+) salts were added to both soils. Values of electrical conductivity (EC1:5), denoted S1, S2, and S3 in each soil, were 0.16, 1.10 and 1.98 dS m−1in the sand and 0.19, 0.82 and 1.75 dS m−1in the clay. Residues of wheat and alfalfa were added at 2% (w/w). Cumulative respiration and microbial biomass decreased with increasing salinity, but with residue addition they increased with a greater rate in amended sandy soil than in clay soil, with a more pronounced effect for alfalfa than for wheat residue. After 10 days, with wheat residue available N values were 113, 86, and 71μg in the clay and 144, 114, and 94μg g−1soil in the sand in S1, S2, and S3, respectively. Relative to wheat residue, alfalfa residue increased N availability by 9, 13, and 19% and 22, 24, and 24% in the clay and in the sand in S1, S2, and S3, respectively. Compared to the control, in the clay P availability increased by 33, 57, and 100% with wheat residue and by 58, 128, and 175% with alfalfa residue, whereas in the sand it increased by 92, 45, and 40% with wheat residue and by 130, 145, and 280% with alfalfa residue in S1, S2, and S3, respectively. Availability of N and P increased from day 10 to day 50 in both soils, but with different magnitudes. Residue addition can increase microbial activity and nutrient availability in saline soils, particularly in coarser textured soils. [ABSTRACT FROM AUTHOR]

The aims of this study were to (1) examine the extent of bacterial contamination of soils subjected to exposure to dairy sewage sludge applied to soils as measured by determination of number of bacteria from the Escherichia coli family and (2) determine the effects of dairy sewage sludge and straw on populations of other microbial species present in gray-brown podzolic soil. The gray-brown podzolic soil was formed from heavy loamy sand, which is characterized by the following granulometric composition: a sand fraction, 65%; a silt fraction, 19%; and a silt and clay fraction; 16%. The brown soil was formed from silt-loam and characterized by the following granulometric composition of silty-clay deposit: sand fraction, 8%; silt fraction, 48%; and clay and silt fraction, 46%. In dairy sewage sludge the total bacteria number as defined by Alef and Nannipieri (1995) was 51 × 104 colony-forming units (cfu)/ kg dry matter (dm), fungi total number 10 × 103 cfu/ kg dm, and E. coli bacteria 9.5 × 103 most probable number (MPN)/kg dm. In dairy sewage sludge mixed with straw, total number of bacteria and total number of fungi decreased to 103 and 102, respectively. Competition for nitrogen, glucose, and lactose and organic acids such as acetic and succinic with soil microorganisms, as well as soil conditions such as lack of oxygen, lower soil pH, and temperature, may account for the reduction in the number of E. coli bacteria in soils to which dairy sewage sludge was applied. Dairy sewage sludge may provide a beneficial impact on soil environment and adversely affect microorganisms such that dairy sewage sludge may be used as a safe organic fertilizer. [ABSTRACT FROM AUTHOR]

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) reflectance and emissivity data were used to discriminate nonphotosynthetic vegetation (NPV) from exposed soils, to produce a topsoil texture image, and to relate sand fraction estimates with elevation data in an agricultural area of central Brazil. The results show that the combination of the shortwave infrared (SWIR) bands 5 and 6 (hydroxyl absorption band) and thermal infrared (TIR) bands 10 and 14 (quartz reststrahlen feature) discriminated dark red clayey soils and bright sandy soils from NPV (crop litter), respectively. The ratio of the bands 10 and 14 was correlated with laboratory measured total sand fraction. When applied to the image and associated with topography, a predominance of sandy soil surfaces at lower elevations and clayey soil surfaces at higher elevations was observed. Areas presenting the largest sand fraction values, identified from ASTER band 10/14 emissivity ratio, were coincident with land degradation processes. [ABSTRACT FROM AUTHOR]

Eight-year-old Loblolly pine (Pinus taeda) plots located in South Carolina were evaluated using high resolution aircraft multispectral scanner data to determine if biomass could be accurately measured. Sixteen pine plots located on both sandy and clay soils were treated with 0, 180, or 360 kg. (approximately 0, 400, or 800 lb.) of nitrogen per plot. Indices of biomass from remote sensing data were significantly correlated with in situ biomass measurements made in each plot. A ratio of infrared (9 - 1.1 μm) and red ( 65-70 μm) channels yielded the best correlation. The indices were not sensitive to differences in soil type (sandy or clay). [ABSTRACT FROM AUTHOR]