Chemical indicators - soil

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Chemical indicators of the quality of organic matter of soil from the Rio das Mortes watershed under different coffee plant managements.

Chemical indicators of the quality of organic matter of soil from the Rio das Mortes watershed under different coffee plant managements.

CHEMICAL INDICATORS OF THE QUALITY OF ORGANIC MATTER OF SOIL FROM THE RIO DAS MORTES WATERSHED UNDER DIFFERENT COFFEE PLANT MANAGEMENTS. This work evaluated the chemical quality of organic matter (OM) of a Brazilian Oxisol cultivated with coffee plants, under organic and conventional managements. Total organic C (TOC), light fraction C (LF-C) and C in humic (HA-C) and fulvic (FA-C) acids fractions was measured. Amongst the evaluated indexes, TOC and LF-C discriminated better OM attributes as a function of management. The stratification ratio (TOC 5-10cm /TOC 10-20cm ) did not show differences between the systems studied. The organic system can contribute to the sustainability of coffee plantations in Brazil, because it maintains the chemical attributes of OM closer to the indexes verified under forest conditions.
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Selection of Indicators to Discriminate Soil Tillage Systems and to Assess Soil Quality in a Red Latosol

Selection of Indicators to Discriminate Soil Tillage Systems and to Assess Soil Quality in a Red Latosol

The CDF 2 separated MT from CT and NT (Figure 3), being the chemical indicators the most efficient in this discrimination (Figure 4). The tendency of the NT is to present better fertility conditions in the superficial layers of the soil, but the best condition is verified mainly in the first 0.05 m of soil depth [54] due to the superficial deposition of fertilizers, lime, and organic residues. In CT the tendency is to find a lower but uniform fertility condition along the profile due to tillage (primary and secondary tillage operations), with higher oxidation of organic residues, higher nutrient leaching and erosion losses. [55], but in the present study there was no such effect, being the fertility found in CT similar to NT because the chemical conditions did not discriminate these systems (Figure 04). This result may be related to the soil depth considered in this study (0–0.10 m) and under NT is expected higher fertility in the most superficial soil depth (0–0.05 m). In addition, increased erosion soil losses that may occur in CT [56] but NT can increased water losses in extreme events due to low MaP and K fs , and due to higher fertility in more superficial layers, nutrient losses tend to be high
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Indicadores químicos e físicos de qualidade do solo / Chemical and physical indicators of soil quality

Indicadores químicos e físicos de qualidade do solo / Chemical and physical indicators of soil quality

The soil is considered a natural resource, becoming extremely important, as it has the ability to promote food production, being fundamental in environmental protection. Studies on soil quality have been increasingly frequent, for this evaluation, there is a wide and complex set of soil indicators that can be used. Thus, the objective of this literature review is to present a concise discussion about the concepts of soil quality and some indicators, emphasizing physical and chemical. The evaluation of soil quality, which is a combination of physical, chemical and biological properties that contributes to the understanding of the limits of each soil, as well as leads to clarify what are the necessary measures for its recovery in case of degradation. The way of cultivating the soil reflects the growing concern with environmental quality, with the preservation of life and the maintenance environmental conditions for future generations, which causes several changes in the way of cultivating the soil, with the objective of reducing human action on the environment, being possible its preservation. The selection of indicators is fundamental for the evaluation of soil quality. A good indicator should be able to reflect the functioning of the ecosystem, identify the forms of disturbances, be economically viable and have ease of monitoring. The physical and chemical indicators of soil quality allow the knowledge of a given site and the transformation process, thus contributing to the management to be adopted.
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Site preparation impacts on physical and chemical forest soil quality indicators

Site preparation impacts on physical and chemical forest soil quality indicators

Forest soils in the Mediterranean region frequently have limited rooting depth, high coarse elements and low organic matter content, which tend to limit water storage in the soil profile. Accordingly, application of site preparation techniques is essential to enhance soil water storage and availability in these environments (Querejeta et al., 2001; Alcázar et al., 2002; Piatek et al., 2003; Imaz et al., 2010). However, site preparation for afforestation currently lacks accurate planning, based on sound experimental results driving to techniques most adequate to each situation and respecting stand productivity and ecosystem sustainability requirements. Improving soil quality is one of the most important factors for sustaining the global biosphere and fundamental in forest systems sustainability (Wang and Gong, 1998). A simple set of established soil properties can provide useful information on soil quality (Sparling et al., 2004). Soil quality has been defined as “the capacity of a soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health'' (Doran and Parkin, 1994). Land use and management practices seriously impact the direction and degree of soil quality changes in time and space (Wang and Gong, 1998). Possibly the most significant impact of site preparation from a soil quality perspective is on rooting depth and soil hydrological processes, because increase the availability of resources that plants have access (water and nutrients). Runoff and sediment loss is commonly highest in the first few years after site preparation, for the reason that canopy cover is scarce and ground vegetation may be insufficient for controlling erosion (Lucci and Della Lena 1994; Figueiredo et al., 2011).
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Soil chemical properties affected by cover crops under no-tillage system

Soil chemical properties affected by cover crops under no-tillage system

The use of no-tillage systems (NTS) is growing in all regions of Brazil, occupying an area of 25 million hec- tares, about 10 million of which are located in soils under Cerrado (CONAB, 2012). These soils are characterized by low soil fertility and low pH (Boer et al., 2007). Using cover crops in NTS could be an important alternative to increase the sustainability of agricultural systems, which may favor increasing soil fertility, and restoring considerable amounts of nutrients to crops. Cover crops with large root systems can uptake nutrients from deep soil layers and after chemical desiccation, during straw degradation, release these nutrients in the soil surface (Duda et al., 2003; Boer et al., 2007; Torres & Pereira, 2008; Pacheco et al., 2011; Cunha et al., 2011). Therefore, vegetation at the soil surface in the NTS can significantly change the chemical properties of the soil (Torres et al., 2005; Crusciol et al., 2005; Rosolem et al., 2006; Boer et al., 2007; Carpim et al., 2008, Garcia et al., 2008; Reddy et al., 2009, Carneiro et al., 2009; Rosolem et al., 2010; Cunha et al., 2011).
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SPATIAL VARIABILITY OF SOIL CHEMICAL PROPERTIES AFTER COFFEE TREE REMOVAL

SPATIAL VARIABILITY OF SOIL CHEMICAL PROPERTIES AFTER COFFEE TREE REMOVAL

Nowadays, knowledge on the variability of soil properties is considered a basic principle for a localized management in precision agriculture for areas at any scale (Grego & Vieira, 2005). Characterizing the spatial variability of the soil chemical properties, particularly in cultivated areas, provides relevant information for a more rational soil use and management (Montezano et al., 2006). Such studies gain particular importance in the case of mapping changes caused by different management methods (Carvalho et al., 1998; Carvalho et al., 2002). In such cases, characterizing the spatial variation of soil properties makes it possible to define differentiated management areas, which may increase the efficiency of fertilizer use and sampling schemes. Geostatistics has been used as an important and efficient strategic tool to characterize spatial variability for detailed soil analysis and description (Grego & Vieira, 2005; Silva et al., 2007). Silva et al. (2007) concluded that the amplitude of chemical soil properties in coffee plantations justifies local and differentiated fertilizer use, and that mean values do not adequately reflect nutrient demands. Marked variations in nutrient
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CHEMICAL PROPERTIES OF SOIL FERTIRRIGATED WITH DAIRY AND SLAUGHTERHOUSE WASTEWATER

CHEMICAL PROPERTIES OF SOIL FERTIRRIGATED WITH DAIRY AND SLAUGHTERHOUSE WASTEWATER

and 7.0, and according to CFSEMG (1999), they present good and high agronomic classification, respectively. The low nitrification and the reduction in the mineralization of the soil organic matter due to the increase of the water content in the soil, which reached 302 mm (Figure 2), equivalent to 21.4 L in each column, may have contributed to the few changes in soil pH values, as Iyyemperumal & Shi (2007) and Doelsch et al. (2010) reported. Some studies corroborate with these results, such as Cabral et al. (2011), who evaluated the impact of swine wastewater (SW) on soil and found that the dosages of 0, 150, 300, 450 and 600 m³ ha -1 of SW did not affect soil pH in
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Phosphorus application for the chemical immobilization of cadmium in contaminated soil.

Phosphorus application for the chemical immobilization of cadmium in contaminated soil.

Comparando-se teores obtidos com os diferentes extratores químicos observa-se que os maiores valores foram com Mehlich-1, que foi quase 3 vezes superior aos do DTPA, ao contrário[r]

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Chemical attributes of a savannah Typic Hapludox soil under management systems

Chemical attributes of a savannah Typic Hapludox soil under management systems

The agricultural use of sewage sludge has become a sensible and promising way of disposing it once it is a good nutrient source, especially regarding phosphorus and nitrogen (BINDER et al., 2002). Phosphorus is considered one of the hindering factors to agricultural yields, due to the adsorption and/or fixation processes in soil colloids (CORRÊA et al., 2005). Sewage sludge usually contains low potassium content due to the obtaining process, the opposite of what happens to phosphorus, which is present in a high content and, most importantly, approximately 80% of it is available in the first application year (SIMONETE et al., 2003). Another important factor is the sewage sludge decomposition in the soil which allows a better uptake of the nutrients by the plants as they are slowly released via the organic matter mineralization process (DEBOSZ et al., 2002).
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The chemical properties of soil for alfalfa production after biofertiliser application

The chemical properties of soil for alfalfa production after biofertiliser application

biofertiliser doses were the primary treatments and the cuts (ive) were subplots. The cuts were performed, on average, every 27 days at 10 cm above the soil. At the end of the experiment, the roots, nodules and soil from all experimental units were collected for chemical analysis. We observed a linear increase in dry matter production of the shoots relative to the doses studied. The dry matter production of the roots and nodules was not signiicantly different. The chemical properties of the soil signiicantly improved for calcium and magnesium as well as the sum of bases and base saturation with biofertiliser application. Biofertilisers can be used for agricultural production and favourably alter the soil characteristics. Key words: Biofertiliser, Medicago sativa, nitrogen, nodules, roots
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Soil microbial and chemical properties influenced by continuous cropping

Soil microbial and chemical properties influenced by continuous cropping

The results obtained in this study revealed that continuous cropping of banana has a significant effect on the soil microbiological and biochemical properties (Figure 3). Soil microorganisms and enzymes are closely correlated with soil biological processes such as nutrient cycling and organic matter decomposition. These soil bio- chemical and microbiological parameters could respond quickly to soil environmental changes. Consequently, soil microbial biomass and enzymes are considered sensitive indicators of soil quality and management impacts (Dick et al., 2000; Kaschuk et al., 2010). Therefore, the study on soil bacterial and biochemical properties is important to understand the effect of management practices on soil quality and develop sustainable agricultural practices.
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Prediction of soil chemical attributes using optical remote sensing

Prediction of soil chemical attributes using optical remote sensing

Therefore, new soil analysis methods that are less costly and faster have been investigated. The application of spectroscopy as a soil analysis method began after Bowers and Hanks (1965) demonstrated that it was possible to quantify soil attributes, such as moisture and organic matter content, by using reflected energy. In view of this, our work aimed to quantify soil chemical attributes using spectral data obtained in the laboratory and establishing their relationship to chemical management. It is expected that evaluation of the spectral data will show a correlation with the soil’s chemical attributes, making quantification of these attributes possible. Material and methods
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Relationship between coffee leaf analysis and soil chemical analysis

Relationship between coffee leaf analysis and soil chemical analysis

production to increase yield and develop more efficient management strategies with greater environmental and economic sustainability. The objectives of this study were to establish critical and optimal levels of soil fertility properties for high yielding Arabica coffee crops using the Boundary Line method and, then, relate the macronutrient contents in the diagnostic leaf of coffee to the macronutrients available in the soil using the Quadrant Diagram of the Plant-Soil Relationship (QDpsR). The study made use of a soil chemical analysis database, leaf macronutrient contents, and Arabica coffee yield from five representative coffee-growing regions in Minas Gerais. An analysis of data consistency was performed, and relative fruit yield (RFY) was related to the soil organic matter (SOM), P, K, Ca, and Mg contents in the soil, establishing the boundary line (BL) in each graph. Equations were adjusted from the BL points, and the equation that best fit was selected. Using the QDpsR method, the response plane was divided into four quadrants, where the total leaf contents of N, P, K, Ca, Mg, and S were plotted as a function of the contents of SOM, P, K, Ca, and Mg in the soil, on the y and x axes of the Cartesian coordinate system. The regression equations were adjusted to the pairs of points (y, x) of quadrants III and I and were used to estimate the macronutrient sufficiency ranges from the critical and optimal levels in the soil. The BL method was used to determine the class of good soil fertility for SOM, P, K, Ca, and Mg. The QDpsR method allows determination of response curves for leaf content as a variable of soil contents, making it possible to estimate the sufficiency ranges in the diagnostic leaf of coffee: 33.4-35.8 g kg -1 of N, 1.4-1.6 g kg -1 of P, 24.4-27.0 g kg -1 of K, 11.9-13.6 g kg -1 of
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Soil indicators to assess the effectiveness of restoration strategies in dryland ecosystems

Soil indicators to assess the effectiveness of restoration strategies in dryland ecosystems

SAI was specifically aimed at highlighting the differences in pedoclimate that may result from the rather detailed combinations of shallow soils, or with limited available water capacity. This value was estimated using software based on the Erosion/Production In- dex Calculation (EPIC) model. SAI was related to easily available climatic and soil data through a multiple regression, linking the SAI value to long-term mean annual air tem-

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Physico-chemical indicators and antibacterial activity of brown propolis against Escherichia coli.

Physico-chemical indicators and antibacterial activity of brown propolis against Escherichia coli.

The activity of 23 samples of ethanolic brown propolis, from the State of Mato Grosso, was investigated against Escherichia coli ATCC 25922. The values of physical and chemical parameters showed significant variation among samples. The percentage of dry extract ranged from 2.6 to 27.6%. The index of oxidation varied from 3 to 519 seconds. All samples showed the percentage of wax higher than the limit preconized by the legislation, with values varying from 3.4 to 74.6%. The quantification of phenolic and flavonoid compounds, responsible for antimicrobial activity, ranged from 0.1 to 5.0 (w/w) and 0.02 to 0.66 (w/w), respectively, being that the higher the index of phenolic compounds the larger the zones of inhibition. Antibacterial activity was observed in seven out of the 23 samples, demonstrating zones of inhibition ranging from 10 to 11.3mm. For these active samples, the minimum inhibitory concentration was determined, ranging from 125 to 1000mg/mL. The value of MIC in 42.9% of these samples was 250mg/mL. These results contribute to the establishment of physical and chemical parameters for the regulation of brown propolis and indicate possible therapeutic applicability in the development of formulations for the treatment of infections caused by E. coli.
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SOIL QUALITY INDICATORS IN A RHODIC KANDIUDULT UNDER DIFFERENT USES IN NORTHERN PARANA, BRAZIL

SOIL QUALITY INDICATORS IN A RHODIC KANDIUDULT UNDER DIFFERENT USES IN NORTHERN PARANA, BRAZIL

Microbial biomass and metabolic activity The highest MBC was found in the soil under native forest, followed by secondary forest, peach-palm and rye. All the other soils had lower MBC and were similar to one another (Table 2). The MBC represents the living fraction of the SOC and nutrients and is considered a sensitive indicator of soil quality because it is easily altered through anthropogenic action, like the conversion of forest to agricultural use, in addition to the impact of different strategies of soil use and management (Kaschuk et al., 2010). It is important to notice that, even after two decades with no anthropogenic interference in the secondary forest soil, the MBC was not reestablished to the levels found in the native forest. Carneiro et al. (2009) observed a reduction of MBC and qMic in soils under different uses and management as compared to a site under native vegetation. The qMic expresses how much of SOC is immobilized in the microbial biomass. Lower values of qMic are usually found in cropped soils (Table 2), an indication of adverse conditions to the
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Indicators of soil quality in the implantation of no-till system with winter crops

Indicators of soil quality in the implantation of no-till system with winter crops

The use of winter crops aims at the soil protection and formation of mulching, which is critical in the NTS. As consequence, there are improvements on physical, chemical and biological properties of soil, which lead to more stability along the cropping seasons some years after the adoption (FRANCHINI et al., 2012) and contribute to increase the sustainability of the production system (SILVA et al., 2008). Characteristics of species to be used as winter cops should include large production of biomass and straw mineralization synchronized with the demands of succeeding plants for nutrients (e.g. corn in the summer crop), besides soil protection and serving as C source for the microbial community, stimulating the C and nutrient cycle, and keeping or increasing the concentrations of SOM. Accordingly, the diversification of straw by using a consortium is promising, like observed for the multicropping of cover crops, in which the black oat contribute to produce biomass and immobilize nutrients, hairy vetch acts as N 2 -fixing plant, and fodder radish contribute to cycle N, especially from deeper soil layers, like nitrate. Despite fodder radish as single winter crop had stimulated some microbiological and biochemical soil attributes, decreased the TOC in 2009, similarly to the wheat crop. Given that oxidic soils for long-term under conventional tillage have low contents of SOM, winter crops that contribute to increase the concentrations by means of higher inputs of residues are very helpful, especially at the beginning of the implantation of NTS.
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Soil quality indicators under management systems in a Quilombola community in the Brazilian Cerrado

Soil quality indicators under management systems in a Quilombola community in the Brazilian Cerrado

ABSTRACT: Soil management systems exert different effects on soil attributes, especially on the organic matter content, and, consequently, the soil aggregation. The aim of this study was to evaluate the impact of different land uses practiced by quilombola family farmers on water stable aggregates, glomalin and organic carbon in soil aggregates. Soil samples were collected at depths of 0-10 and 10-20 cm from areas cultivated under the following management systems: 1) conventional corn plantation (MA), 2) cultivation of citrus trees intercropped with annual crops (AC) (a conservationist approach), 3) pasture of Brachiaria (Urochloa spp.) (PA), and, as refer- ence, an area of the Cerrado (CR) free of any anthropogenic interference. The studied areas were evaluated in a completely randomized design, with five replications, in a subplot scheme. The plots were the management systems and the subplots the depths. Soil macro-aggregates were predominant at both depths and the aggregate stability indices were higher than 90 % for all management systems. Total organic carbon in the two aggregate classes (micro and macro- aggregates) correlated with the MWD (mean weight-diameter), but not with the easily extractable glomalin (EEG) related soil protein. Soil micro and macro-aggregates, EEG and MWD discrimi- nated management systems and are important soil quality indicators. The carbon content in both micro-aggregates (C-MIC) and macro-aggregates (C-MAC) of the intercropped system (AC) was higher than in the CR. The soil attributes that best separated the areas were C-MIC, MWD and EEG in macro-aggregates for the depth of 0-10 cm, and EEG in micro-aggregates, together with MWD and C-MAC for the depth of 10-20 cm.
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DISSOLVED ORGANIC CARBON AND BIOAVAILABILITY OF N AND P AS INDICATORS OF SOIL QUALITY

DISSOLVED ORGANIC CARBON AND BIOAVAILABILITY OF N AND P AS INDICATORS OF SOIL QUALITY

ABSTRACT: Soil quality has become an important issue in soil science. Considerable attempts have been made to define soil quality, but a general concept has not yet been accepted by the scientific community. The selection of quantitative indices for soil quality is extremely difficult, and a considerable number of chemical, physical, and biochemical properties have been suggested as potential indicators of soil quality. Because soil organic matter (SOM) can be associated with different soil chemical, physical and biological processes, it has been widely considered as one of the best soil quality indicator. Land use can significantly influence dynamics of organic carbon and N, P, and S cycle. However, changes in total soil organic carbon (SOC) contents in response to land use may be difficult to detect because of the natural soil variability. In the short to medium term, biological properties and readily decomposable fractions of SOC, such as dissolved organic carbon (DOC), are much more sensitive to soil management than is SOM as a whole, and can be used as a key indicator of soil natural functions. Despite the fact that labile C accounts for a small portion of the total organic matter in the soils, DOC is the most mobile and important C-source for microorganisms, and can easily reflect the effects of land use on soil quality. Although several methods are used to characterize DOC, the factors influencing mineralization and bioavailability of elements associated with organic matter (N, P, and S) remains unclear. Future research should focus on the processes that govern DOC and nutrient dynamics and how they affect soil quality.
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ARTIGO_Microbiological indicators of soil quality under native forests are influenced by topographic factors

ARTIGO_Microbiological indicators of soil quality under native forests are influenced by topographic factors

Abstract: Several microbiological indicators of soil quality present high sensitivity, but little is known about the influence of topographic factors on them. This work aimed to evaluate variability of biological indicators of soil quality across a hillslope under native forest and the influence of topographic factors on them. Four positions on a hillslope were evaluated. Activity of the enzymes β-glucosidase, acid phosphatase, urease and fluorescein diacetate (FDA) hydrolysis were determined, as well as basal and substrate-induced respiration, and density of microorganisms: total bacteria, total fungi, actinobacteria, phosphate solubilizers, ammonifiers, native rhizobia, free-living N 2 -fixing bacteria, spores of arbuscular mycorrhizal fungi and percentage of root colonization by arbuscular mycorrhizal fungi. Activity and density of microorganisms were correlated with topographic factors. The relation of these factors to the variations of the evaluated indicators was determined using the random forest algorithm. Microbiological indicators varied according to the hillslope positions. The indicators urease, basal respiration, spore density, mycorrhizal colonization, total bacteria and fungi, phosphate solubilizers, and free-living N 2 - fixing bacteria detected in JNFB and FAM culture medium did not vary with terrain attributes and were therefore more indicated in cases of topographic variations. This and future studies can help to select the best microbiological indicators for different conditions.
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