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1.
The water-stability of soil and coprolite aggregates in soddy-podzolic soils and the participation of fungi in the formation
of water-stable aggregates from earthworm (Aporrectodea caliginosa) coprolites were assessed. The water stability of the soil and coprolite aggregates in the soils increased in the following
sequence: potato field—mown meadow—mixed forest. The fungal mycelium reserves increased in the same sequence. The water stability
of the coprolite aggregates of Aporrectodea caliginosa inhabiting these soils is 2–2.5 times higher than that of the soil aggregates of the same size (3–5 mm). The inhibition of
the growth of fungi by cycloheximide decreased the water stability of the coprolite aggregates, on the average, by 15–20%. 相似文献
2.
F. Ponder Jr Fumin Li Diann Jordan Edwin C. Berry 《Biology and Fertility of Soils》2000,32(2):166-172
The influence of compaction on Diplocardia ornata (Smith) burrowing and casting activities, soil aggregation, and nutrient changes in a forest soil were investigated using
pot microcosms. Treatments included two levels each of compaction, organic matter, and earthworms. Both burrowing and casting
activities were more abundant in uncompacted soil than in compacted soil. Bulk density decreased in microcosms of compacted
soil containing D. ornata from 1.76 g cm–3 to 1.49 g cm–3 over the study period. The overall percent of aggregates in the same size classes in compacted soil was less than the percent
of aggregates in uncompacted soil. The mean percent of aggregates in earthworm casts for size classes 0.25–1.00 mm was higher
for compacted soil than for uncompacted soil. The reverse was true for aggregates in class sizes 2.00–4.00 mm. Soil compaction
also affected soil microbial biomass carbon and soil inorganic N concentrations. These results indicate that the burrowing
and casting activities of earthworms in compacted forest soils, as in soils of agricultural and pastured lands, can help ameliorate
disturbed soils by improving aggregation, reducing bulk density, and increasing nutrient availability.
Received: 1 September 1999 相似文献
3.
Experimental studies and the analysis of published data have shown that carbon reserves in soils generally increase upon soil
exclusion from agricultural use. The rate of carbon accumulation in the abandoned soils depends on the soil type, the time
elapsed since the soil abandoning (the restoration period), and the thickness of the layer for which the rate of carbon accumulation
is determined. For the upper 20-cm-thick layer, it varies from 66 to 175 g C/m2 per year in dependence on the type of soil and averages 111 g C/m2 per year. The highest rate is typical of the first 10–15 years of soil restoration. According to our calculations, the carbon
sequestration in the upper 20-cm-thick layer of Russian soils due to changes in land use was 184–673 Mt C in 1990–2005 and
may reach 282–1030 Mt C by 2020. 相似文献
4.
Xiao Ming Shi Xiao Gang Li Rui Jun Long Bhupinder Pal Singh Zhuo Ting Li Feng Min Li 《Biology and Fertility of Soils》2010,46(2):103-111
This study is aimed at quantifying organic carbon (C) and total nitrogen (N) dynamics associated with physically separated
soil fractions in a grassland-cultivation sequence in the Qinghai-Tibetan plateau. Concentrations of organic C and N of soil,
free and occluded particulate organic matter (OM), and aggregate- and mineral-associated OM in different land uses are increased
in the following order: 50 years cultivation < 12 years cultivation ≤ native grassland. The prolonged cropping of up to 50 years
markedly affected the concentrations of free and occluded particulate OM and mineral-associated OM. After wet-sieving, 43%
of native grassland soil mass was found in >1−10 mm water-stable aggregates that stored 40% of bulk soil organic C and N;
only 16% and 7% of soil mass containing 16% and 7% of bulk soil organic C and N was >1−10 mm water-stable aggregates of soils
cultivated for 12 years and 50 years, respectively. This indicated that losses of soil organic C and N following cultivation
of native grassland would be largely related to disruption of >1–10 mm size aggregates and exposure of intra-aggregate OM
to microbial attack. Organic C and N concentrations of soil aggregates were similar among aggregate size fractions (>0.05−10 mm)
within each land use, suggesting that soil aggregation process of these soils did not follow the hierarchy model. The increase
of the C-to-N ratio of free and occluded particulate fractions in the cultivated soils compared to the grassland soil indicated
a greater loss of N than C. 相似文献
5.
Thermal diffusivity of the upper horizons of leached meadow-chernozemic soils varies in dependence on the soil water content
within the following limits: 1.20–4.11 × 10−7 m2/s for the Ap horizon, 1.21–3.85 ×10−7 m2/s for the A1 horizon, and 1.35–3.73 × 10−7 m2/s for the A1B horizon. The relationships between the thermal diffusivity and the soil water content are described by S-shape
curves with a long gently inclined segment within the range of water contents of <0.20 cm3/cm3, a distinct rise in thermal diffusivity within the water contents from 0.20 to 0.30–0.35 cm3/cm3, and a flattened or somewhat declining segment in the area with the high (>0.30–0.35 cm3/cm3) water contents. The thermal diffusivity of air-dried soil samples correlates with the physical clay (<0.01 mm) content.
The Pearson correlation coefficient for these two variables equals −0.67 and is statistically significant at the significance
level of 0.05. Regression equations allowing one to calculate the thermal diffusivity of the investigated soil horizons on
the basis of data on the soil water content have been obtained. 相似文献
6.
Effect of solid waste compost on microbiological and physical properties of a burnt forest soil in field experiments 总被引：2，自引：0，他引：2
C. Guerrero I. Gómez J. Mataix Solera R. Moral J. Mataix Beneyto M. T. Hernández 《Biology and Fertility of Soils》2000,32(5):410-414
The restoration of soil microbial activities is a basic step in the reclamation of burnt soils. For this reason, the ability
of municipal solid waste compost to accelerate the re-establishment of bacterial and fungal populations, as well as to re-establish
physical properties in a burnt soil, was evaluated in a field experiment. Four treatments were performed by adding different
doses of compost (0, 0.5, 1 and 2 kg compost m–2 soil) to a burnt Calcic Rodoxeralf soil, and the changes in microbial populations, salt content, aggregate stability and
bulk density were evaluated for 1 year. Initially, the addition of compost had a negative effect on soil microbial populations,
but 3 months after compost addition, the number of viable fungal propagules increased in all the amended soils. This positive
effect lasted until the end of the experiment. From 30 days onwards, all the amended soils showed a greater total number of
bacterial cell forming units than the unamended burnt soil. Organic amendment increased the percentage of 2- to 4-mm aggregates,
although the effect on the stability of the 0.2- to 2-mm aggregates and on bulk density was less noticeable.
Received: 24 November 1999 相似文献
7.
The lower Himalayan regions of north‐west India experienced a severe land‐use change in the recent past. A study was thus conducted to assess the effect of grassland, forest, agricultural and eroded land uses on soil aggregation, bulk density, pore size distribution and water retention and transmission characteristics. The soil samples were analysed for aggregate stability by shaking under water and water drop stability by using single simulated raindrop technique. The water‐stable aggregates (WSA) >2 mm were highest (17·3 per cent) in the surface layers of grassland, whereas the micro‐aggregates (WSA < 0·25 mm) were highest in eroded soils. The water drop stability followed the similar trend. It decreased with the increase in aggregate size. Being lowest in eroded soils, the soil organic carbon also showed an adverse effect of past land‐use change. The bulk density was highest in eroded lands, being significantly higher for the individual aggregates than that of the bulk soils. The macroporosity (>150 µm) of eroded soils was significantly (p < 0·05) lower than that of grassland and forest soils. The grassland soils retained the highest amount of water. Significant (p < 0·05) effects of land use, soil depth and their interaction were observed in water retention at different soil water suctions. Eroded soils had significantly (p < 0·05) lower water retention than grassland and forest soils. The saturated hydraulic conductivity and maximum water‐holding capacity of eroded soils were sufficiently lower than those of forest and grassland soils. These indicated a degradation of soil physical attributes due to the conversion of natural ecosystems to farming system and increased erosion hazards in the lower Himalayan region of north‐west India. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
8.
Influence of the soil properties and human activity on the hysteresis of the moisture retention function in organic soils The hysteresis of the moisture retention function is characterized by the greatest difference of water content during drying and wetting (ΘAΘB) at the same suction. It diminishes by an increased degree of peat decomposition, ash content, bulk density and pH and increases with the volume of macropores (Ø > 50 μm). In the soil suction range Ψ = –1 to –6 kPa the hysteresis can be calculated by multiple regression equations (Tab. 3). Under arable land compared with grassland the hysteresis increases depending on the soil looseness and diminution of soil aggregates. A sand cover on peatland leads in the upper (20–30 cm) layer to a diminution of hysteresis proportional to the sand thickness. 相似文献
9.
E. Sh. Elizbarashvili T. F. Urushadze M. E. Elizbarashvili Sh. E. Elizbarashvili M. K. Schaefer 《Eurasian Soil Science》2010,43(4):427-435
The thermal regime of the different soil types of Georgia has been studied on the basis of soil temperature records obtained
at 60 weather stations in 1947–1995. It is shown that the thermal conductivity and temperature gradients in the soil profiles
depend on the soil type. In the upper 0–20 cm of the soils in the intermontane depressions, the lowest temperature gradients
in the summer are typical of the red ferrallitic soils (0.5–1.1°C/dm), and the highest gradients are observed in the chernozems
of eastern Georgia (1.0–1.3°c/dm). The soil temperature gradients are especially high in the late spring (1.4–1.8°c/dm), when
the atmospheric convection is formed. In the mountains, the lowest gradients in the summer are observed in the cinnamonic
soils (0.4–0.9°c/dm), and the highest gradients are established in the brown forest soils (0.5–1.3°c/dm). The redistribution
of the temperatures in the deeper layers depends on the soil texture. The lowest temperature gradient is in the soils of Telavi
(3.1°c/m), where a stony layer is found at the depth of 60 cm, which causes the good heating of the deep layers. The highest
gradients are seen in the clayey and loamy soils of western (Chakva, 3.8°c/m) and eastern (Tbilisi, 3.9°c/m) Georgia. This
is probably related to the high water content in the heavy-textured soils. 相似文献
10.
V. P. Kalinichenko V. K. Sharshak O. S. Bezuglova E. P. Ladan E. D. Genev V. V. Illarionov V. E. Zinchenko N. A. Morkovskoi V. V. Chernenko L. P. Il’ina 《Eurasian Soil Science》2011,44(8):927-938
Changes in the properties of solonetzic soil associations (chestnut solonetzic soils and chestnut solonetzes) in the dry steppe
after their reclamation have been studied for 30 years. The reclamation included the deep three-tier plowing and the approach
of rotary tillage. A single rotary tillage operation resulted in the formation of fine aggregates of equal sizes in the plow
layer; any morphological features of the restoration of solonetzic pedogenesis are absent. The atmospheric moisture easily
penetrates into the soil, and soluble salts are leached off to a great depth. In 30 years since the soil amelioration with
the use of a PMS-70 rotary tiller, the humus content has increased up to 3.3% in the upper 20-cm-thick layer and up to 2.4%
in the layer of 20–40 cm. The content of adsorbed Na+ in the 20- to 30-cm-thick layer has decreased to 10.6% of the cation exchange capacity (in comparison with 19.8% in the nonreclaimed
soil). The spatial heterogeneity of the soil cover has decreased in comparison with that prior to the reclamation. During
the entire observation period, crop yields gained from the fields reclaimed with the use of the rotary tiller have been by
25–60% higher in comparison with those on the fields with traditional treatments. 相似文献
11.
A. A. ShinkarevJr. I. P. Breus S. A. Neklyudov V. A. Breus 《Eurasian Soil Science》2010,43(9):993-1003
The effect of two methods for the preparation of soil samples for sorption experiments—hard (dehydration at 105°C) and mild
(drying over P2O5 at 20°C in vacuum) drying—on the values of the vaporphase sorption of p-xylene was studied depending on the content of organic matter in the soil. It was shown with dark gray forest and chernozemic
soils as examples that the hard drying of soil samples taken from the upper layer of the humus profile with a high content
(>4%) of organic carbon decreased their sorption capacity in the range of 0–5% by 7–81%. Therefore, the method is unsuitable
for these soils. It was also found that the mild method of soil preparation had obvious analytical advantages. 相似文献
12.
土地利用方式对红壤和黄壤颗粒有机碳和碳黑积累的影响 总被引：19，自引：0，他引：19
颗粒有机碳和碳黑是土壤中两类性质不同的碳库,它们的数量可反映土壤有机质的稳定性。结果表明,浙江省红壤和黄壤中这两类碳库有很大的变化,并与土地利用方式存在联系。颗粒有机碳的数量及其占总有机碳的比例:林地>茶园>旱地;而碳黑占总有机碳的比例一般是:旱地、茶园>次生林地>原生林地。颗粒有机碳是土壤碳库的易变组分,易受利用方式改变而变化,颗粒有机碳占总有机碳的比例随土壤有机质的积累而增加。相同土地利用方式土壤中碳黑数量与粘粒呈正比。土壤中>1 mm水稳定性团聚体与颗粒有机碳含量相关,而土壤<0.25 mm团聚体与碳黑含量相关。 相似文献
13.
Changes in the physical, physicochemical, and biological properties of cultivated gray forest soils after their abandoning
and overgrowing with meadow and forest vegetation for 8–10 years are clearly seen in the upper part of the former plow layer.
The organic matter content and the content of available forms of phosphorus and potassium increase; a significant increase
in the root biomass and in the soil biological activity is observed. Changes in the physical properties—an increase in the
degree of soil aggregation and a decrease in the bulk density values—are seen in the upper and middle parts of the former
plow layer. The biological factor is the major factor of transformation of formerly cultivated gray forest soils upon their
abandoning and overgrowing with meadow and forest vegetation. At the same time, a significant role in the improvement of the
structural state of the soils belongs to the physical shrink-swell and freezing-thawing processes. 相似文献
14.
The proportional differences in soil organic carbon (SOC) and its fractions under different land uses are of significance for understanding the process of aggregation and soil carbon sequestration mechanisms. A study was conducted in a mixed vegetation cover watershed with forest, grass, cultivated and eroded lands in the degraded Shiwaliks of the lower Himalayas to assess land‐use effects on profile SOC distribution and storage and to quantify the SOC fractions in water‐stable aggregates (WSA) and bulk soils. The soil samples were collected from eroded, cultivated, forest and grassland soils for the analysis of SOC fractions and aggregate stability. The SOC in eroded surface soils was lower than in less disturbed grassland, cultivated and forest soils. The surface and subsurface soils of grassland and forest lands differentially contributed to the total profile carbon stock. The SOC stock in the 1.05‐m soil profile was highest (83.5 Mg ha−1) under forest and lowest (55.6 Mg ha−1) in eroded lands. The SOC stock in the surface (0–15 cm) soil constituted 6.95, 27.6, 27 and 42.4 per cent of the total stock in the 1.05‐m profile of eroded, cultivated, forest and grassland soils, respectively. The forest soils were found to sequester 22.4 Mg ha−1 more SOC than the cultivated soils as measured in the 1.05‐m soil profiles. The differences in aggregate SOC content among the land uses were more conspicuous in bigger water‐stable macro‐aggregates (WSA > 2 mm) than in water‐stable micro‐aggregates (WSA < 0.25 mm). The SOC in micro‐aggregates (WSA < 0.25 mm) was found to be less vulnerable to changes in land use. The hot water soluble and labile carbon fractions were higher in the bulk soils of grasslands than in the individual aggregates, whereas particulate organic carbon was higher in the aggregates than in bulk soils. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
15.
F. R. Zaidelman A. S. Nikiforova L. V. Stepantsova V. P. Volokhina 《Eurasian Soil Science》2012,45(5):459-471
Dark gray soils in the Tambov Plain are developed from the light-textured glaciofluvial deposits underlain by the calcareous loam. Their morphology, water regime, and productivity are determined by the depth of the slightly permeable calcareous loamy layer, relief, and the degree of gleyzation. The light texture of the upper layer is responsible for its weak structure, high density, the low content of productive moisture, and the low water-holding capacity. If the calcareous loam is at a depth of 100?C130 cm, dark gray soils are formed; if it lies at a depth of 40?C70 cm, temporary perched water appears in the profile, and dark gray contact-gleyed soils are formed. Their characteristic pedofeatures are skeletans in the upper layers, calcareous nodules in the loamy clay layer, and iron nodules in the podzolized humus and podzolic horizons. The appearance of Fe-Mn concretions is related to gleyzation. The high yield of winter cereals is shown to be produced on the dark gray soils; the yields of spring crops are less stable. Spring cereals should not be grown on the contact-gleyed dark gray soils. 相似文献
16.
Unique experiments performed since the 1950s at the Arshan’-Zel’men Experimental Station have formed the basis for afforestation in the dry steppe and semidesert zone without irrigation on the salt-affected soils of solonetzic soil complexes of the Ergeni Upland. Ameliorative measures favored the accumulation of productive moisture in the upper 2-m-thick soil layer, which ensured the growth of trees and the partial leaching of soluble salts to a depth of 1–1.4 m. However, no complete desalinization of the soil profiles took place. The degree of removal of exchangeable sodium from the exchange complex (soil dealkalization) was smaller. The monitoring of changes in the salt status of the soils upon agroforest reclamation was performed until the early 1980s. Our investigations of 2005–2006 showed that the soil amelioration is still in progress: the salt maximum in the profile of the solonetzes descended to a depth of 2.2 m, and the exchangeable sodium was lost from the plow layer (0–40 cm). Plowed soils between forest shelterbelts were also subjected to desalinization and dealkalization of their soil profile, though less intensely than those under the shelterbelts. 相似文献
17.
长期不同施肥方式对华北地区温室和农田土壤团聚体形成特征的影响 总被引：8，自引：1，他引：8
土壤的团聚状况是土壤重要的物理性质之一,团聚体数量是衡量和评价土壤肥力的重要指标。施用有机肥是提高土壤有机碳(SOC)含量、促进土壤团聚体形成和改善土壤结构的重要措施。本文以华北地区曲周长期定位试验站的温室土壤和农田土壤为研究对象,运用湿筛法,对比研究施用化肥(NP)、有机肥加少量化肥(NPM)、单施有机肥(OM)3种施肥方式对温室和农田两种利用方式土壤水稳性团聚体含量、分布和稳定性的影响,以提示施肥措施对不同土地利用方式土壤水稳性团聚体特征的影响。结果表明:在温室土壤和农田土壤中,OM处理较NP和NPM处理显著降低了土壤容重,增加了土壤有机质含量(P0.05),且在0~10 cm土层中效果最为明显。其中在温室土壤0~10 cm土层,单施有机肥处理(OM1)的土壤容重为1.17 g·cm~(-3),分别较施用化肥(NP1)和有机肥加少量化肥(NPM1)处理降低12.0%和8.6%,OM1的土壤有机质含量为54.81 g·kg~(-1),较NP1和NPM1增加104.8%和35.7%;在农田土壤0~10 cm土层,单施有机肥处理(OM2)的土壤容重为1.19 g·cm~(-3),较施用化肥(NP2)、有机肥加少量化肥(NPM2)分别降低8.5%和7.0%,OM2的土壤有机质为22.67 g·kg~(-1),较NP2、NPM2分别增加23.1%和15.0%。温室土壤和农田土壤中,0~10 cm、10~20 cm和20~40 cm层土壤团聚体的平均重量直径(MWD)和几何平均直径(GMD)均为OMNPMNP;OM处理下水稳性团聚体的分形维数(D)值最低,NP处理下最大。OM处理显著降低0~20 cm土层内水稳性团聚体的D值,表层0~10 cm土层效果最为明显,土壤结构明显得到改善;相比农田土壤,温室土壤稳定性指标变化最为明显,团聚体结构改善效果最好。土壤有机质含量与0.25 mm水稳性团聚体含量间呈极显著正相关关系(P0.001),说明土壤有机质含量越高,0.25 mm水稳性团聚体的含量就越高,土壤团聚体水稳性越强,土壤结构越稳定。因此有机施肥方式能在补充土壤有机碳库和有效养分含量的同时,显著增加土壤中大团聚体的含量及其水稳性,是提高华北平原农田土壤、尤其是温室土壤结构稳定性和实现土壤可持续发展的有效措施。 相似文献
18.
V. Kuráž J. Frouz M. Kuráž A. Mako V. Shustr J. Cejpek O. V. Romanov E. V. Abakumov 《Eurasian Soil Science》2012,45(3):266-272
The water-physical properties (bulk density, air conductivity, texture, water content, and temperature dynamics) were studied
in a chronosequence of soils developing on self-overgrowing quarry-dump complexes in the area of Sokolov, Czechia. The area
overgrown for 12 years was covered by a thin grass cover; osiers were observed after 20 years of overgrowth; a broadleaved
forest was found on a plot after 45 years of overgrowth. The particle-size distribution in the soil was determined using peptization
by pyrophosphate and the FAO method. When the soil was prepared by the FAO method, a predominance of physical clay (62–72%)
in the dump material was revealed; at the use of pyrophosphate peptization, the content of this fraction was lower (18–19%).
The observed differences can be due to the incomplete degradation of the microaggregates composed of clay particles during
the peptization by pyrophosphate. A decrease in the field water content of the soils with the increasing time of the dump’s
overgrowth was observed. This could be attributed to the more significant evapotranspiration of the perennial woody vegetation
compared to the herbaceous plants, which agreed with the data on the projective cover of plants and their root biomass. A
decrease in the soil temperature in the root-inhabited layer (in the diurnal variation) with the age of succession was also
observed. The analysis of the data on the field soil water content and their comparison with the results of the laboratory
measuring of the wilting points indicated that the development of plants could be restricted by a water deficit at the 20-
and 45-year-old stages of the succession. 相似文献
19.
The effect of the temperature and moisture on the emission of N2O from arable soils was studied in model experiments with arable soils at three contrasting levels of wetting and in a wide
temperature range (from −5 to +25°C), including freeze-thaw cycles. It was shown that the losses of fertilizer nitrogen from
the soils with water contents corresponding to 60 and 75% of the total water capacity (TWC) did not exceed 0.01–0.09% in the
entire temperature range. In the soils with an elevated water content (90% of the TWC) at 25°C, the loss of fertilizer nitrogen
in the form of N2O reached 2.35% because of the active denitrification. The extra N2O flux initiated by the freeze-thaw processes made up 88–98% of the total nitrous oxide flux during the entire experiment. 相似文献
20.
The analysis of long-term (since 1947) data on the water content of the upper 3-m-thick layer in the Streletskaya Steppe chernozems
under annual mowing showed that the weather changes during the last decades (from 1972–1973 to 2005–2006) resulted in an increase
in the soil wetting depth during the fall-winter-spring period and the frequency of the percolation, a decrease in the water
consumption from the 150- to 300-cm layer during the growing season, and a decrease in the water deficit in the fall. Therefore,
the total water content of the steppe chernozems increased, although to a significantly lesser degree than that found for
the steppe plot with a succession of woody-shrub vegetation. In a perennial fallow, the water content of the soil layer also
increased. The water supply of the 0- to 160-cm layer of chernozems under winter wheat and corn underwent no significant changes. 相似文献