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1.
The Mediterranean area of Southern Italy is characterized by different natural plant covers that mainly reflect different successional stages (i.e. low maquis, high maquis, Quercus ilex wood) and managed areas with introduced plant species (such as Pinus species). Soil properties could be affected by plant cover types as well as by plant species. Our objective was to determine the relationships of plant cover types and plant species with the chemical and biological characteristics of the soil. In four neighbouring areas with different plant cover types (low maquis, pure high maquis, high maquis with pines and pinewood, with pines planted by foresters in both cases), soil samples were collected under different plant species in order to evaluate the effect of plant cover types and plant species on soil properties. Soil samples were analyzed for nutrient content, microbial biomass, soil potential respiration and enzymatic activity (phosphatase, arylsulphatase, β-glucosidase and hydrolase activities) as well as for pH, water holding capacity (WHC) and cation exchange capacity (CEC). Application of cluster analysis and principal component analysis to the data revealed that the plant cover type was the key factor influencing soil properties more than plant species. In fact, the largest differences were observed between pure high maquis soils and all other soils, with pure high maquis soils generally showing the highest values of WHC, CEC, nutrient content, organic and microbial C, soil respiration, phosphatase, arylsulphatase and β-glucosidase activities. The significantly lower values of these variables in the low maquis relative to the pure high maquis probably reflect the effect of ecological succession on soil. The high maquis with pine, differing from the pure high maquis only for the presence or absence of pine, showed values of soil physical, chemical and biological characteristics similar to those found in the low maquis, thus suggesting that the presence of pine retards soil development.  相似文献   

2.
《Applied soil ecology》2007,37(2-3):107-115
Maquis is a dense evergreen shrub layer which, in semi-arid Mediterranean lands, is commonly linked to the presence of well-conserved soils with large contents of mineralizable substrates. It was our aim to test whether: (i) maquis promotes soil microbial biomass and activity, and (ii) mature pine plantations without a shrubby understory support microbial biomass and activity levels comparable to those of stands with maquis. Surface soil samples were taken in four sites that sustain pine plantations (PP), maquis with pines (MP), maquis (MQ) and grasslands (GS). Microbial biomass was inferred from the C content in the soil microbiota. The ATP content in fresh samples and the CO2–C production from incubated samples were used to assess microbial activity, as was the activity of β-glucosidase and alkaline phosphatase. Topsoils under maquis (MP and MQ) were the most fertile, both chemically (high organic carbon contents) and physically (low bulk density, high aggregate stability) and showed by far the largest levels of microbial biomass and activity. These levels in soils under PP, which sustained a successful plantation in terms of tree canopy density but lacked the shrubby understory, were significantly smaller than those of the adjacent shrubland with pines (MP). Redundancy analysis extracted a main axis explaining 67% of the variation of the microbiological soil properties, which was interpreted as an environmental gradient of soil fertility. Along this axis, the samples were separated according to the presence or absence of a maquis dominated by late-successional species; other factors such as soil type, slope position and aspect were less influential. The effects of afforestation practices on the detritus-based system should be considered in the design of future forest restoration strategies in desertification-threatened lands.  相似文献   

3.
作物种植会对农田生态系统产生一定的影响。大田试验条件下,在黑龙江省853农场岗地白浆土上连续6年种植玉米、大豆、小麦、水稻,研究了土壤理化性质以及土壤中与碳、氮、磷、硫元素转化相关的9种水解酶活性和动力学特性的响应;同时研究了不同作物种植对土壤脲酶、磷酸单酯酶、磷酸二酯酶、芳基硫酸酯酶及β-葡糖苷酶动力学特性的影响。结果表明,大豆连作土壤的有效氮、总碳、总氮、总磷和总硫含量都稍高;大豆处理土壤pH值略低,但其它三种作物种植下的土壤均呈微酸性,差异不显著。土壤水解酶动力学参数对种植作物的反应与表观活性的反应不一致。玉米连作土壤蛋白酶和磷酸单酯酶活性高于其它处理;小麦处理的磷酸二酯酶和芳基硫酸酯酶活性最高,水稻连作土壤蛋白酶、磷酸二酯酶和磷酸三酯酶活性最低。连年种植小麦处理的土壤脲酶、磷酸二酯酶以及芳基硫酸酯酶Vmax显著高于其它处理,小麦连作土壤β-葡萄糖苷酶、脲酶、磷酸二酯酶和芳基硫酸酯酶的Vmax/Km值显著高于其它处理,可以看出在此处理下土壤酶具有较强的催化潜势。  相似文献   

4.
A laboratory experiment was conducted to study the impact of metalaxyl application at different concentration levels on microbial biomass and the biochemical activities in soil. A dissipation study of metalaxyl highlighted 52.5-56.8% loss of metalaxyl due to the presence of microbial activity. However, a small but significant decline in microbial biomass was observed on 60 d of incubation period. Metalaxyl showed a highly significant effect in decreasing total N and organic C content in soil from 0 to 30 d of incubation. Dehydrogenase, phosphatase, urease, arylsulphatase and β-glucosidase activities were monitored in metalaxyl treated soils. Except urease, all the enzymatic activities initially increased and then decreased. Urease activity showed a continuous gradual decrease throughout the experimental period. Thus, metalaxyl might influence the growth and development of crop-plants, since it has direct impact on nutrient recycling and energy flow in soil.  相似文献   

5.
6.
Twenty one topsoils, selected to represent major New Zealand soil groups were collected from developed, grazed pasture and examined for microbiological and biochemical characteristics. Organic C and total N levels ranged from 2.4–46% (mean 8.7%) and 0.22–2.31% (mean 0.65%), respectively. The characteristics examined included microbial biomass (mean 1240 μg Cg?1 soil), min-N flush (mean 85 μg N g?1 soil), microbial P (mean 52 μg P g?1 soil), min-N and CO2 produced, nitrification index, urease, protease, phosphatase and arylsulphatase activities. Most of these characteristics were generally higher than the values already published possibly due to high levels of organic matter.Principal component analysis of the correlation matrix showed two distinct groups of characteristics: CO2 produced, N mineralized, total N, organic C, microbial biomass, microbial P and phosphatase comprising one group and arylsulphatase, min-N flush, urease and nitrification index comprising the other group. Protease activity and soil pH were not strongly associated with each other or the other groups.  相似文献   

7.
Longer and more severe drought periods are expected in the near future for Mediterranean ecosystems. Soil enzymes play an essential role in the nutrient mineralization and their activity is an exceptional sensor in predicting the capacity of nutrient supply to plants. We conducted an experiment of water availability manipulation in evergreen oak mountain stands with the aim to study the effects of enhanced drought on the activity of five soil enzymes. The drought treatment consisted of runoff exclusion by a ditch along the entire top edge of the upper part of treatment plots and partial rain exclusion by suspending PVC strips and funnels. The reduction of 10% of soil moisture produced by runoff exclusion decreased urease activity by 10-67%, protease activity by 15-66% and β-glucosidase activity by 10-80%, depending on annual period and soil depth. The reduction of 21% of soil moisture produced by runoff and rainfall exclusion together reduced urease activity by 42-60%, protease activity by 35-45%, β-glucosidase activity by 35-83% and acid phosphatase activity by 31-40%. No significant effects were observed on alkaline phosphatase activity. The activities of the enzymes involved in the nitrogen cycle, protease and urease, were the most affected by drought. In all cases, the activities of these enzymes strongly decreased with soil depth and they were greater in spring than in autumn. These results show the link between drought and a slower nutrient turn-over, which decreases the nutrient supply to plants.  相似文献   

8.
H. KANG  C. FREEMAN 《土壤圈》2007,17(6):681-687
The nature of the interactions between microbes and roots of plants in a peaty soil were studied in a laboratorybased experiment by measuring activities of β-glucosidase, phosphatase, N-acetylglucosaminidase, and arylsulphatase. The experiment was based on control (autoclaved), bacteria-inoculated, and plant (transplanted with Dactylorhiza) treatments, and samples were collected over 4 sampling intervals. Higher enzyme activities were associated with the bacteria-inoculated treatment, suggesting that soil enzyme activities are mainly of microbial origin. For example,β-glucosidase activity varied between 25-30μmol g^-1 min^-1 in the bacteria-inoculated samples whilst the activity of the control ranged between 4-12 μmol g^-1 min^-1. A similar pattern was found for all other enzymes. At the end of the incubation, the microcosms were destructively sampled and the enzyme activities determined in bulk soil, rhizospheric soil, and on the root surface. Detailed measurement in different fractions of the peat indicated that higher activities were found in rhizosphere. However, the higher activities of β-glucosidase, N-acetylglucosaminidase, and arylsulphatase appeared to be associated with bacterial proliferation on the root surface, whilst a larger proportion of phosphatase appeared to be released from root surface.  相似文献   

9.
Microorganisms are the regulators of decomposition processes occurring in soil, they also constitute a labile fraction of potentially available N. Microbial mineralization and nutrient cycling could be affected through altered plant inputs at elevated CO2. An understanding of microbial biomass and microbial activity in response to belowground processes induced by elevated CO2 is thus crucial in order to predict the long-term response of ecosystems to climatic changes. Microbial biomass, microbial respiration, inorganic N, extractable P and six enzymatic activities related to C, N, P and S cycling (β-glucosidase, cellulase, chitinase, protease, acid phosphatase and arylsulphatase) were investigated in soils of a poplar plantation exposed to elevated CO2. Clones of Populus alba, Populus nigra and Populus x euramericana were grown in six 314 m2 plots treated either with atmospheric (control) or enriched (550 μmol mol−1 CO2) CO2 concentration with FACE technology (free-air CO2 enrichment). Chemical and biochemical parameters were monitored throughout a year in soil samples collected at five sampling dates starting from Autumn 2000 to Autumn 2001.

The aim of the present work was: (1) to determine if CO2 enrichment induces modifications to soil microbial pool size and metabolism, (2) to test how the seasonal fluctuations of soil biochemical properties and CO2 level interact, (3) to evaluate if microbial nutrient acquisition activity is changed under elevated CO2.

CO2 enrichment significantly affected soil nutrient content and three enzyme activities: acid phosphatase, chitinase and arylsulphatase, indicators of nutrient acquisition activity. Microbial biomass increased by a 16% under elevated CO2. All soil biochemical properties were significantly affected by the temporal variability and the interaction between time and CO2 level significantly influenced β-glucosidase activity and microbial respiration. Data on arylsulphatase and chitinase activity suggest a possible shift of microbial population in favour of fungi induced by the FACE treatment.  相似文献   


10.
In this paper is studied the dynamics of the soil microbial structure and function, and enzymatic activities during a chronosequence (0, 5, 10, 15 and 20 years) after reclamation of coal mine areas with wheat (Triticum aestivum). Due to the homogeneity induced by monoculture all over the sites, similarity in the dynamics of structural and functional soil attributes was expected. Moreover, the idea of Whisenant (2002) claiming non monotonic succession unfolding during the reclamation process was checked. Soil samples were collected from the upper 12 cm of cultivated fields differing in their post-reclamation age, and they were analyzed for physicochemical variables, microbial community structure (PLFAs), catabolic profiles (Biolog Ecoplates) and enzymatic activities (β-glucosidase, urease and alkaline phosphatase). Fields outside the mine area, cultivated with the same species were used as controls. Exhibiting rapid growth from 0 to 4–5 years after reclamation, slow decline from 5 to 10 years and stabilization after 10 years, the abundances of the microbial groups (Gram+, Gram, fungi, protozoa) showed similar dynamics. Similar dynamics displayed also the activity of alkaline phosphatase and β-glucosidase, which increased gradually from 0 to 10 years and stabilized afterwards. By contrast, the activity of urease showed an inverse temporal pattern. After 15 years, the microbial abundances, the functional diversity (Shannon index), and the soil enzymatic activities of the reclaimed soils converged to values recorded in the controls fields. Significant shifts in the microbial community structure were not detected, probably because of the type of reclamation (agricultural use). However, when the overall PLFA and carbon utilization data sets were analyzed, it was revealed that the microbial community structure changed non monotonically in the transition between 0 and 5 years after reclamation, while the carbon utilization profiles exhibited more complex successional patterns. Above findings support the idea of non monotonic successional processes in soil microbial communities.  相似文献   

11.
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 β-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 β-glucosidase activities were hardly affected by air-drying of degraded and non-degraded soils from the two locations studied in all seasons. Short incubations (4, 8 and 12 d at 23 °C) of rewetted air-dried soil at 55% of water-holding capacity showed different patterns depending on the enzyme studied. Urease and β-glucosidase activities were relatively stable during incubation, with several significant (P<0.05) 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 β-glucosidase activities determined in air-dried 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.  相似文献   

12.
Shrub encroachment is a worldwide phenomenon with implications for desertification and global change. We evaluated its effects on the activities of urease, phosphatase and β-glucosidase in Mediterranean semiarid grasslands dominated by Stipa tenacissima by sampling 12 sites with and without resprouting shrubs along a climatic gradient. The presence of shrubs affected the evaluated enzymes at different spatial scales. Soils under S. tenacissima tussocks and in bare ground areas devoid of vascular plants had higher values of phosphatase and urease when the shrubs were present. For the β-glucosidase, this effect was site-specific. At the scale of whole plots (30 m × 30 m), shrubs increased soil enzyme activities between 2% (β-glucosidase) and 22% (urease), albeit these differences were significant only in the later case. Our results indicate that shrub encroachment does not reduce the activity of extracellular soil enzymes in S. tenacissima grasslands.  相似文献   

13.
Zhang  Wenyuan  Liu  Shun  Zhang  Manyun  Li  Yinan  Sheng  Keyin  Xu  Zhihong 《Journal of Soils and Sediments》2019,19(7):2913-2926
Purpose

Rhizosphere and fertilization might affect soil microbial activities, biomass, and community. This study aimed to evaluate the impacts of Phyllostachys edulis (moso bamboo) rhizospheres on soil nutrient contents and microbial properties in a moso bamboo forest with different fertilizer applications and to link soil microbial activities with abiotic and biotic factors.

Materials and methods

The experiment included three treatments: (1) application of 45% slag fertilizer (45%-SF); (2) application of special compound fertilizer for bamboos (SCF); and (3) the control without any fertilizer application (CK). Simultaneously, bulk soils and 0.5, 2.5, 4.5, and 6.5-year-old (y) bamboo rhizosphere soils were selected. Soil nutrient contents were analyzed. Microbial activities were evaluated based on the activities of soil enzymes including β-glucosidase, urease, protease, phosphatase, and catalase. The total microbial biomass and community were assessed with the phospholipid fatty acids (PLFAs) method.

Results and discussion

In the CK and SCF treatments, organic matter contents of rhizosphere soils were significantly higher than those of bulk soils. Soil β-glucosidase, urease, protease, phosphatase, and catalase activities in rhizosphere soils were higher than those of bulk soils, with the sole exception of β-glucosidase of 0.5 y rhizosphere soil in the 45%-SF treatment. Compared with the CK treatment, fertilizer applications tended to increase soil total PLFAs contents and changed soil microbial community. Moso bamboo rhizospheres did not significantly increase the total microbial biomass. In the SCF treatment, the Shannon index of bulk soil was significantly lower than those of rhizosphere soils.

Conclusions

Our results suggested that both rhizospheres and fertilizer applications could change the soil microbial community structures and that moso bamboo rhizosphere could increase microbial activity rather than biomass in the forest soils with different fertilizer applications.

  相似文献   

14.
Alkaline and acid phosphomonoesterase, β-glucosidase, arylsulfatase, protease and urease activities, CO2-C evolution and ATP content were monitored in long-term Cd-contaminated (0-40 mg Cd kg−1 dry weight soil) sandy soils, kept under maize or ‘set aside’ regimes, amended with plant residues. The organic matter input increased soil respiration, ATP contents and hydrolase activities in all soils. However, the Cd-contaminated soils had significantly higher metabolic quotients (qCO2), as calculated by the CO2-to-ATP ratio, and significantly lower hydrolase activities and hydrolase activity-to-ATP ratios for alkaline phosphomonoesterase, arylsulfatase and protease activities, compared with the respective uncontaminated soils. The ratios between acid phosphomonoesterase, β-glucosidase and urease activities and ATP were unaffected. A significantly higher qCO2/μ ratio, an expression of maintenance energy, was observed in most of the contaminated soils, indicating that more energy was required for microbial synthesis in the presence of high Cd concentrations. It was concluded that exposure to high Cd concentrations led to a less efficient metabolism, which was responsible for lower enzyme activity and synthesis and lower hydrolase activity-to-ATP ratios observed in these Cd-contaminated soils.  相似文献   

15.
Changes in land use frequently modify the capacity of ecosystems to provide services. The purpose of this study was to investigate the effects of a specific land-use change, i.e. from meadows to pine plantations under temperate climate, on soil enzyme activities. To this aim, the variation of five key soil enzyme activities (dehydrogenase, β-glucosidase, arylsulphatase, acid phosphatase and urease) was evaluated in different sites located in the Urdaibai Reserve of the Biosphere (northern Spain). Lower values of dehydrogenase [effect size, computed as 100 × (1 − mean value from pine plantations/mean value from meadows), was 82.9%], β-glucosidase (52.9%) and urease (52.5%) activity were observed in soils from pine plantations versus meadows. Acid phosphatase and arylsulphatase activity showed a pattern of variation that was not dependent on land-use. The largest variation in enzyme activity values was due to changes at the small scale, not between the studied sites, an encouraging finding for the suitability of enzyme activities as bioindicators of the impact of land-use changes on soil functioning. Our results suggest that nutrient cycling (as reflected by the values of soil enzyme activities) might have been modified as a consequence of replacing meadows by pine plantations.  相似文献   

16.
Soil enzymes are critical to soil nutrient cycling function but knowledge on the factors that control their response to major disturbances such as wildfires remains very limited. We evaluated the effect of fire-related plant functional traits (resprouting and seeding) on the resistance and resilience to fire of two soil enzyme activities involved in phosphorus and carbon cycling (acid phosphatase and β-glucosidase) in a Mediterranean shrublands in SE Spain. Using experimental fires, we compared four types of shrubland microsites: SS (vegetation patches dominated by seeder species), RR (patches dominated by resprouter species), SR (patches co-dominated by seeder and resprouter species), and IP (shrub interpatches). We assessed pre- and post-fire activities of the target soil enzymes, available P, soil organic C, and plant cover dynamics over three years after the fire. Post-fire regeneration functional groups (resprouter, seeder) modulated both pre- and post-fire activity of acid phosphatase and β-glucosidase, with higher activity in RR and SR patches than in SS patches and IP. However, we found no major differences in enzyme resistance and resilience between microsite types, except for a trend towards less resilience in SS patches. Fire similarly reduced the activity of both enzymes. However, acid phosphatase and β-glucosidase showed contrasting post-fire dynamics. While β-glucosidase proved to be rather resilient to fire, fully recovering three years after fire, acid phosphatase showed no signs of recovery in that period. Overall, the results indicate a positive influence of resprouter species on soil enzyme activity that is very resistant to fire. Long-lasting decrease in acid phosphatase activity probably resulted from the combined effect of P availability and post-fire drought. Our results provide insights on how plant functional traits modulate soil biochemical and microbiological response to fire in Mediterranean fire-prone shrublands.  相似文献   

17.
Enzymatic activity (EA) was explored as a possible tool for composting characterization. Three composts (yard wastes, cotton wastes and a mixture of the two) were sampled during different phases of the process and divided in two fractions. The first was immediately analysed for microbial biomass C (BC) and EAs (β-glucosidase, arylsulphatase, acid and alkaline phosphatase). The second fraction was air-dried prior to analysis for the same EAs and for organic C (CORG), total N (NTOT), dissolved organic C (DOC), extractable C (CE) and humic-like C (CH).BC decreased throughout the composting period (149 days), whereas EA in moist fractions stabilized between 50 (β-glucosidase, alkaline phosphatase) and 90 (arylsulphatase, acid phosphatase) days of composting.EA was always reduced by air‐drying (β-glucosidase: 40-80%; arylsulphatase: 10-50%; acid phosphatase: 10-70%; alkaline phosphatase: 50-90%), but this effect was less prominent as composting proceeded, especially for β-glucosidase and alkaline phosphatase.EA in air-dried samples displayed the same trend as in moist ones, except that there was a marked difference (47-66%) between initial and final activities of all four enzymes.EAs in air‐dried compost and content of humic-like substances showed a similar trend: a marked increase in the first 90 days of the process and no significant variations afterwards. This suggests that the formation of humic-enzymatic complexes has taken place and indicates that this process occurs almost totally during the first stage of composting.EA steadiness in air-dried samples occurred concurrently with the achievement of compost stability, as indicated by the conventional indexes (i.e. CH, CORG/NTOT). Therefore, the development of a stable enzyme activity in air-dried compost could represent a simple measure of compost stabilization in routine analysis of composting process.  相似文献   

18.
本文首次对我国原始土壤的酶活性及其与土壤肥力因素的相关性作了初步研究。结果表明:随着岩生地衣向苔藓、草甸的演替。过氧化氢酶。转化酶、脲酶、蛋白酶、磷酸酶活性逐渐降低,多酚氧化酶活性逐渐升高;转化酶、蛋白酶、磷酸酶和脲酶活性与有机质非常显著相关(10.0相似文献   

19.
《Applied soil ecology》2006,31(3):162-173
Microorganisms are the regulators of decomposition processes occurring in soil, they also constitute a labile fraction of potentially available N. Microbial mineralization and nutrient cycling could be affected through altered plant inputs at elevated CO2. An understanding of microbial biomass and microbial activity in response to belowground processes induced by elevated CO2 is thus crucial in order to predict the long-term response of ecosystems to climatic changes. Microbial biomass, microbial respiration, inorganic N, extractable P and six enzymatic activities related to C, N, P and S cycling (β-glucosidase, cellulase, chitinase, protease, acid phosphatase and arylsulphatase) were investigated in soils of a poplar plantation exposed to elevated CO2. Clones of Populus alba, Populus nigra and Populus x euramericana were grown in six 314 m2 plots treated either with atmospheric (control) or enriched (550 μmol mol−1 CO2) CO2 concentration with FACE technology (free-air CO2 enrichment). Chemical and biochemical parameters were monitored throughout a year in soil samples collected at five sampling dates starting from Autumn 2000 to Autumn 2001.The aim of the present work was: (1) to determine if CO2 enrichment induces modifications to soil microbial pool size and metabolism, (2) to test how the seasonal fluctuations of soil biochemical properties and CO2 level interact, (3) to evaluate if microbial nutrient acquisition activity is changed under elevated CO2.CO2 enrichment significantly affected soil nutrient content and three enzyme activities: acid phosphatase, chitinase and arylsulphatase, indicators of nutrient acquisition activity. Microbial biomass increased by a 16% under elevated CO2. All soil biochemical properties were significantly affected by the temporal variability and the interaction between time and CO2 level significantly influenced β-glucosidase activity and microbial respiration. Data on arylsulphatase and chitinase activity suggest a possible shift of microbial population in favour of fungi induced by the FACE treatment.  相似文献   

20.
The effectiveness of adding two organic wastes (cotton gin crushed compost, CGCC, and poultry manure, PM) to a saline soil (Salorthidic Fluvaquent) in dryland conditions near Seville (Guadalquivir Valley, Andalusia, Spain) was studied during a period of 5 years. Organic wastes were applied at rates of 5 and 10 t organic matter ha−1. One year after the assay began, spontaneous vegetation had appeared in the treated plots, particularly in that receiving a high PM dose. After 5 years the plant cover in this treated plot was around 80% (compared with the 8% of the control soil). The effect on the soils physical and chemical properties, soil microbial biomass, and six soil enzymatic activities (dehydrogenase, urease, protease, β-glucosidase, arylsulfatase, and phosphatase activities) were ascertained. Both added organic wastes had a positive effect on the physical, chemical and biological properties of the soil, although at the end of the experimental period, the soil physical properties, such as bulk density, increased more significantly in the CGCC-amended soils (23%) and the exchangeable sodium percentage (ESP) decreased more significantly in the CGCC-amended soils (50%) compared to the unamended soil. Water soluble carbohydrates and soil biochemical properties were higher in the PM-amended soils compared to the CGCC-amended soils (by 70% for water soluble carbohydrates, and by 34, 18, 37, 39, 40 and 30% for urease, protease, β-glucosidase, phosphatase, arylsulfatase and dehydrogenase activities, respectively). After 5 years, the percentage of plant cover was >50% in all treated plots and 8% in the control soil.  相似文献   

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