Effect of air-drying treatment on enzymatic activities of soils affected by anthropogenic activities (original) (raw)
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Soil Biology & Biochemistry, 2006
Soil enzyme activities are useful indicators of soil quality as they are very sensitive to disturbance. Sample storage or pre-treatments could affect the results in these assays, which are normally determined in fresh samples, kept cold or frozen. The objectives of this study were to (i) evaluate the effect of air-drying or air-drying and rewetting on b-glucosidase, acid phosphatase and urease activities in soils from different locations, degradation status and sampling seasons, and (ii) assess if air-drying or air-drying and rewetting is an accurate sample storage and pre-treatment procedure for enzyme activities in soil quality evaluations under semiarid Mediterranean conditions. Our results showed that urease, phosphatase and b-glucosidase activities were hardly affected by air-drying of degraded and nondegraded soils from the two locations studied in all seasons. Short incubations (4, 8 and 12 d at 23 1C) of rewetted air-dried soil at 55% of water-holding capacity showed different patterns depending on the enzyme studied. Urease and b-glucosidase activities were relatively stable during incubation, with several significant (Po0.05) shifts up and down in some soils and samplings. However, acid phosphatase showed an increase in activity with incubation, of between 5% and 50% relative to air-dried samples. These increases followed no pattern and were unrelated to soil characteristics or sampling date. Hence, urease, phosphatase and b-glucosidase activities determined in airdried soil samples seem to be representative of those obtained under field-moist conditions. In contrast, short incubations of rewetted soil samples can produce fluctuations in these enzyme activities, mainly of acid phosphatase, and estimations in these conditions are not so representative of field-moist soil values. r
Air-drying pretreatment effect on soil enzymatic activity
Plant, Soil and Environment, 2017
Air-drying of soil samples is a common practice for all-purpose soil testing. However, it may cause the cessation of microbial activity changing the biochemical attributes. For this reason, field-moist samples are commonly used in the assessment of the enzyme activity in soils. This practice may, therefore, discourage the use of enzymes in soil quality evaluations. This study evaluated the effects of air-drying on cellulase, arylsulfatase and acid phosphatase activities in soil; the hypothesis was that the activities of these enzymes determined in air-dried soil samples are similar to those obtained at field-moist samples. Soil samples were collected (0–10 cm) in a long-term experiment that received two rates (10 and 20 t/ha) of sewage sludge and mineral fertilizer and was cropped with maize. Collected soil samples were split into two groups. In the first one, the enzymes were determined at field-moist samples, while in the second one, the samples were air-dried before enzymatic ana...
Soil Biology and Biochemistry, 1986
The microbial biomass C in 20 grassland soils from New Zealand was estimated using the CHCl, fumigation method and from the rate of respiration using a modified substrate-induced respiration technique (SIR). Estimates were made before and after air-drying. The ATP contents and the activities of the enzymes phospho-monoesterase and phospho-diesterase of moist and air-dried soils were also measured. The fumigation method gave erratic results on dried soils and poor agreement with biomass C estimated by the SIR method. The SIR biomass C, ATP content, phospho-monoesterase and phosphodiesterase activities all declined after air-drying, the average decrease being by 39, 68, 38 and 29%, respectively.
Characterization of soil enzyme activities and physicochemical
Understanding of soil properties to maintain the soil health and crop productivity in agricultural ecosystem is vital. As a consequence, soil type and its related chemical and biological characters are being evaluated to determine the quality of soil. In this study, soil properties in tea monocropping areas were evaluated for 21 tea gardens under waterlogged condition from North Bank (NB), South Bank (SB) of the Assam and Dooars region of West Bengal (WB). A total of 260 samples from 21 tea gardens were collected for three season including pre-rainy (January-May), rainy (June-September) and post-rainy (October-December) and evaluated for different chemical and biological activities. It was found that the NB soil type was sandy to silty loam with an average age of 43 to 80 years while the SB soil type was loam to silty loam with an average age of 50 to 70 years. The soil underlying tea gardens in WB was sandy loam to heavy soil with sandy patches and the age of cultivation was above 70 years. The soils of all the tea gardens were riiildly acidic (pH values from 3.6 to 5.9). The moisture content, soil respiration and temperature of the soils in each of the gardens showed significant variation. A mixed clustering was obtained for the tea gardens with much variation during pre-and post rainy based on studied soil parameters. It was also found that there was a significant correlation during the post-rainy seasons for enzyme activities including urease, phosphatase and dehydrogenase (P less than 0.05), respectively. During pre-rainy, six principal factors influence the soil characteristics with a variance level of 49.26%. During rainy, principal factors urease and phosphatase showed negative effects over the other soil factors whereas in post-rainy pH was the significant principal factor followed by urease, moisture and temperature at the variance level of 25.97%. From the observation it could be concluded that the variations in soil physical, chemical and biological properties were observed among soils from tea gardens of Assam and WB. These variations in soil characteristics under waterlogged conditions were due to variation in the soil texture, management practice. The present finding will help in improvement of tea production by establishing correlation with soil characters.
Applied Soil Ecology, 2015
Air-drying soil samples causes a rapid cessation of microbial activity and is a useful means of storing soil samples and standardizing experiments as moisture levels can be accurately controlled. In contrast to temperate soils, there is little information regarding the advantages and disadvantages of using fieldmoist or air-dried soil samples in the assessment of enzyme activities in tropical soils. The aim of this study was to evaluate the effects of air-drying and a two-year storage period on b-glucosidase, acid phosphatase and arylsulfatase activities in soil samples from cultivated and non-cultivated clayey Oxisols from the Cerrado region. Cultivated soil samples (0-10 cm depth) were collected from 24 treatments in three long-term experiments and analyzed to determine their enzyme activities and soil organic carbon (SOC). These treatments presented a large range of extractable Mehlich-P values and cumulative corn and soybean yields. Non-cultivated soil samples from four nearby areas with native Cerrado vegetation were also included in the study. In the laboratory, soil samples were divided into two groups. In the first group, soil samples were separated, stored at 7 C at field moisture levels and sieved through a 4 mm sieve. The analyses were performed within 1 week after sampling. In the second group, soil samples were air-dried at room temperature for two weeks, sieved through a 2 mm sieve and stored for 2 years at room temperature. Average reductions of 26%, 53% and 72%, were observed in the activities of b-glucosidase, arylsulfatase and acid phosphatase in the air-dried long-term stored samples, in both cultivated and noncultivated Cerrado clayey Oxisols. Air-drying and long-term storage hardly changed the ranking of treatments for b-glucosidase, arylsulfatase and acid phosphatase. However, a reduction in the capacity to detect changes among treatments was observed for acid phosphatase, which prevents the recommendation of air-drying prior to its analyses. As long as the effects of air-drying upon soil enzymes activities are well established, this pretreatment can be used for b-glucosidase and arylsulfatase analyses in the Cerrado clayey Oxisols. 2015 Elsevier B.V. All rights reserved.
The activities of extracellular enzymes are important in understanding decomposition of soil organic matter in wetlands subjecting to drying. The activity of soil extracellular enzymes (β-glucosidase, N-acetylglucosaminidase, and phosphatase), and related physicochemical parameters were monitored in constructed freshwater wetlands during a one-month drying manipulation. Drying increased redox potential and decreased soil water content significantly (P < 0.05). Higher content of soil organic matter (P < 0.05) and higher concentrations of inorganic N (nitrate, P < 0.01; and ammonia, P < 0.001) were also observed significantly under drying condition. Soil hydrolase enzyme activities were stimulated significantly (β-glucosidase, P < 0.05; N-acetylglucosaminidase, P < 0.01; and phosphatase, P < 0.001), and a two-phase pattern of enzyme activities was revealed under drying condition. The increase of soil enzyme activities under drying condition was significantly related to soil redox potential (P < 0.001). Drying strongly affected soil enzyme activities only when soil water content remained above an optimal level for enzymatic catalysis (higher than 23% w/w), corresponding to redox potentials below 250–300 mV. Our results suggest that, under drying condition, potential enzyme activities may be regulated by redox potential, in respect to soil moisture, and consequently alter nutrient availability in wetlands.
Changes in Soil Enzymatic Activity Caused by Hydric Stress
Polish Journal of Environmental Studies
The increase in flooding in Europe is linked to the presence of excessive moisture in many areas. Enzymes are a sensitive parameter of soil environment, therefore we have made an attempt to assess the impact of simulated flood conditions on their activity. We determined the activity of dehydrogenases and acid and alkaline phosphatase after 7 and 14 days of flooding the three Fluvisols with river water in controlled conditions. The obtained results indicate a significant influence of soil moisture on enzymatic activity and soil pH, which indicates that the soil environment is changing as a result of flooding.
2012
Microbial activity is significantly influenced by soil texture, hydrological regimes, flow dynamics, chemical pollutants, and an assessment of these changes is essential for soil management. In the present investigation, soil microbial activity (as an index of soil enzymes i.e. amylase, invertase, protease and dehydrogenase) and its relationship with different physico-chemical properties with respect to seven different soils has been addressed. The variation of soil enzyme activity in question was significantly attributable to differences in soil texture, C, N and P content, bulk density, water holding capacity, moisture content and soil pH. Comparative analysis of soil enzyme revealed that there was gradual increase in amylase, invertase, protaease and dehydrogeanse activity from a nutrient deficient situation (fresh mine spoil) to an enriched soil (forest soil). Stepwise multiple regression analysis was performed to determine the contribution of different factors influencing the v...
European Journal of Soil Biology, 2020
The mobilization of soil nutrients bound in organic matter is largely mediated by enzymes derived from plants, soil microorganisms and animal residues. Land-use change alters important soil characteristics that may affect the activities of soil enzymes. However, mechanistic understanding of how land use and management practices influence the catalytic properties of enzymes in top-and subsoil are still scarce, especially in African ecosystems. We linked catalytic properties i.e. substrate affinity constant (K m) and maximum reaction rate (V max), determined by Michaelis-Menten kinetics, to a set of environmental and microbial variables in the soils of a landuse sequence (6 ecosystems) ranging from natural forests to agricultural fields at Mt. Kilimanjaro. The sensitivity of K m and V max of four extracellular hydrolytical enzymes, β-galactosidase, cellobiohydrolase, phosphatase and chitinase to changing environmental conditions were tested by fluorogenic substrates in topsoils and subsoils. The β-galactosidase activity increased with increasing soil depth. Other extracellular enzyme (cellobiohydrolase, phosphatase and chitinase) activities decreased with depth. The affinity of enzymes to substrates was higher in soils of natural compared to agricultural ecosystems: i.e. higher under forests than under cropland. The activity of β-galactosidase, cellobiohydrolase and chitinase enzyme were highest in lower mountain forest and grassland (less disturbed ecosystems). This indicated that changes in land use and management practice not only affects enzyme activity but also controls enzyme kinetics (K m and K a) thus pointing towards the expression of different enzyme systems. Therefore, we concluded that anthropogenic activities result in alteration of C and nutrient cycling by affecting microbial activities and enzymes catalytic properties.