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Biopores are hotspots of nutrient mobilisation and shortcuts for carbon (C) into subsoils. C processing relies on microbial community composition, which remains unexplored in subsoil biopores. Phospholipid fatty acids (PLFAs; markers for living microbial groups) and amino sugars (microbial necromass markers) were extracted from two subsoil depths (45–75 cm ; 75–105 cm) and three biopore types: (I) drilosphere of Lumbricus terrestris L., (II) 2-year-old root biopores and (III) 1.5-year-old root biopores plus six 6 months of L. terrestris activities. Biopore C contents were at least 2.5 times higher than in bulk soil, causing 26–35 times higher Σ PLFAs g-1 soil. The highest Σ PLFAs were found in both earthworm biopore types; thus, the highest soil organic matter and nutrient turnover were assumed. Σ PLFAs was 33% lower in root pores than in earthworm pores. The treatment affected the microbial community composition more strongly than soil depth, hinting to similar C quality in biopores: Gram-positives including actinobacteria were more abundant in root pores than in earthworm pores, probably due to lower C bioavailability in the former. Both earthworm pore types featured fresh litter input, promoting growth of Gram-negatives and fungi. Earthworms in root pores shifted the composition of the microbial community heavily and turned root pores into earthworm pores within 6 months. Only recent communities were affected and they reflect a strong heterogeneity of microbial activity and functions in subsoil hotspots, whereas biopore-specific necromass accumulation from different microbial groups was absent. 相似文献
3.
Fertigation offers vast potential for efficient use of water and nutrients in sustainable orchard management. Beside minimizing losses, their distribution within the rhizosphere is of utmost importance. In present investigations, most of feeder roots were observed within 30 cm soil depth. Under drip fertigation, wetting front extended horizontally up to 45 cm from emitter. However, the maximum moisture content remained confined within 30 cm distance. Vertically, soil moisture also remained higher in the 0–30 cm soil layers. Under surface irrigation, deeper soil layers registered higher moisture content. Available nitrogen (N) and potassium (K) under fertigation closely followed the moisture distribution pattern. Fertigation plus mulch resulted in 20% fertilizer and 15% water savings over fertigation without mulch. Beside 33% higher fruit yield and 25% water savings, and fertigation plus mulch resulted in 20 percent fertilizer and 40% water savings over surface irrigation. 相似文献
4.
Soil conditions under no-tillage (NT) are often unfavorable for the growth of maize roots in comparison to conventional tillage (CT). In 1997 and 1999, the impacts of tillage on the morphology and spatial distribution of maize (Zea mays L.) roots at anthesis were investigated in a 5-year field trial at two sites (loamy silt and sandy loam soils) in the Swiss midlands. Four soil cores, perpendicular to the maize row, were taken to a depth of 100 cm in each plot; the root length density (RLD), the mean root diameter (MD), and the relative length per diameter-class distribution (LDD) of the roots were determined.
Roots were longer and thinner in 1999 than in 1997. The RLD was significantly higher and the MD was smaller on the loamy silt than on the sandy loam. The RLD and MD decreased with the distance from the plant row. Most of the maize roots, about 80% of the total root length, were in the layer from 0 to 40 cm, with maximum values from 5 to 10 cm; the thickest roots were in the soil layer from 10 to 50 cm. Significant differences in RLD with increasing distance from the row of plants were found in the top 30 cm.
Averaged over the whole soil profile, RLD was higher and MD was smaller under CT than under NT. The impact of tillage on RLD and MD interacted with spatial factors and years. Within the soil profile, RLD was significantly higher under NT than under CT at a depth of 5 cm, whereas it was higher under CT than under NT below 10 cm. Below 50 cm, there was no difference in RLD between the tillage systems. In a horizontal direction, MD was consistently higher in the row and lower in the mid-row under NT than under CT.
Our results show that differences in maize root growth between tillage systems, which were reported in previous studies, persist until anthesis. The accumulation of maize roots near the soil surface in NT suggests that subsurface-banding of starter fertilizer is a more efficient way of applying fertilizer (particularly immobile nutrients such as phosphorus) compared with broadcasting in order to supply sufficient nutrients for NT maize. 相似文献
5.
J. A. M. Barej S. Pätzold U. Perkons W. Amelung 《European Journal of Soil Science》2014,65(4):553-561
Improving phosphorus (P) accessibility in subsoils could be a key factor for sustainable crop management. This study aims to explain the quantity of different P fractions in subsoil and its biopore systems, and to test the hypothesis that crops with either fibrous (fescue) or tap‐root systems (lucerne and chicory) leave behind a characteristic P pattern in bulk subsoil, biopore linings and the rhizosphere. The crops were cultivated for up to 3 years in a randomized field experiment on a Haplic Luvisol developed from loess. Aqua regia‐extractable P (referred to as total P) and calcium acetate lactate‐extractable P (PCAL) were assessed at 0–30 (Ap horizon), 30–45 (E/B horizon), 45–75 and 75–105 cm subsoil depths. In addition, sequential P fractionation was performed on different soil compartments between 45 and 75 cm depths. The results showed that total P stocks below the Ap horizon (30–105 cm) amounted to 5.6 t ha?1, which was twice as large as in the Ap, although the Ap contained larger portions of PCAL. Both PCAL and sequential P extractions showed that biopore linings and the rhizosphere at the 45–75 cm depth were enriched, rather than depleted, in P. The content of inorganic P (81–90% of total P) increased in the following order: bulk soil = biopores <2 mm ≤ rhizosphere ≤ biopores >2 mm. Biopores >2 mm and rhizosphere soil were clearly enriched in resin‐ and NaHCO3‐extractable Pi and Po fractions. However, we failed to attribute these P distribution patterns to different crops, suggesting that major properties of biopore P originated from relict biopores, rather than being influenced by recent root systems. The stocks of the sum of these P fractions in the bulk subsoil (182 kg ha?1 at 45–75 cm depth) far exceeded those in the biopores (3.7 kg ha?1 in biopores >2 mm and 0.2 kg ha?1 in biopores <2 mm). Hence, these biopores may form attractive locations for root growth into the subsoil but are unlikely to sustain overall plant nutrition. 相似文献
6.
黄土丘陵区油松人工林和白桦天然林细根垂直分布及其与土壤养分的关系 总被引：10，自引：0，他引：10
在黄土高原子午岭林区,对油松人工林、白桦天然林细根生物量、比根长、根长密度和细根表面积的垂直分布特征,以及这些根系指标与土壤水分、土壤容重、氮素和有机质的关系进行了研究。结果表明,油松人工林细根生物量随土壤深度增加呈单峰曲线,白桦林细根生物量随土壤深度增加呈减少趋势;油松林大部分根系生物量集中分布在040.cm土层中,其中020.cm土层占37%以上,2040.cm集中了41%以上;表层土壤(020.cm)具有较高的比根长、根长密度和细根表面积,而底层(4060.cm)的比根长、根长密度和细根表面积最低。油松林土壤全氮和有机质含量垂直变化趋势相似,随土壤深度的增加而降低;硝态氮(NO3--N)均随土壤深度的增加呈单峰曲线变化趋势,而铵态氮(NH4+-N)随土壤深度增加呈先降低后增加的抛物线趋势。白桦林75%的细根生物量集中在020.cm土层,比根长、根长密度和细根表面积的垂直分布规律与油松林相似,表层土壤白桦林细根表面积是油松人工林的3.91倍,而2040.cm土层白桦林细根表面积比油松人工林降低了33%。白桦林土壤全氮、有机质含量、NO3--N和NH4+-N垂直变化趋势与油松林相似。土壤水分、容重、全氮和有机质对油松和白桦细根分布的影响明显大于NH4+-N和NO3--N。白桦林表层土壤有机质含量与细根生物量的相关性达到显著水平(r=0.99,P0.05),白桦林表层土壤有机质含量与比根长和根长密度的相关性(分别为r=0.91,r=0.8)低于油松林(分别为r=0.95,r=0.94)。油松和白桦林040.cm土层细根表面积与土壤全氮相关性随土壤深度增加而下降,比根长和根长密度与土壤全氮相关性随土壤深度增加而增大。油松和白桦林2060.cm土层细根生物量、细根表面积和根长密度随有机质含量的减少而增加,而比根长呈相反的变化规律。 相似文献
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Penetration resistance, bulk density, soil water content and root growth of oats were intensively studied in a tilled and an untilled grey brown podzolic loess soil. Bulk density and penetration resistance were higher in the top layer of the untilled soil compared with the tilled soil. In the latter, however, a traffic pan existed in the 25–30 cm soil layer which had higher bulk density and penetration resistance than any layer of the untilled soil. Above the traffic pan, rooting density (cm root length per cm3 of soil) was higher but below the pan it was lower than at the same depth in the untilled soil. Root growth was linearly related to penetration resistance. The limiting penetration resistance for root growth was 3.6 MPa in the tilled Ap-horizon but 4.6-5.1 MPa in the untilled Ap-horizon and in the subsoil of both tillage treatments. This difference in the soil strength-root growth relationship is explained by the build up of a continuous pore system in untilled soil, created by earthworms and the roots from preceding crops. These biopores, which occupy < 1% of the soil volume, can be utilized by roots of subsequent crops as passages of comparatively low soil strength. The channeling of bulk soil may counteract the possible root restricting effect of an increased soil strength which is frequently observed in the zero tillage system. 相似文献
8.
Naila Kaneez-e-Batool Faisal Mahmood Sabir Hussain Muhammad Riaz Zahid Maqbool 《Archives of Agronomy and Soil Science》2016,62(9):1285-1292
More than 50% of global soil organic carbon stocks are stored below 20 cm of soil depth capable of massively altering global C cycle and climate. However, subsoil C dynamics are largely overlooked implicitly assuming that surface and subsoil C dynamics are similar. Here, we compared the soil C dynamics in surface and subsurface soil layers in response to nitrogen and maize leaf litter additions. Soils, sampled from 0 to 5, 15 to 35, 35 to 55 and 55 to 75 cm depths, were incubated at 25°C after adding litter, nitrogen (NH4NO3) or litter plus nitrogen. Soil respiration (C mineralization) was measured throughout the incubation period. Litter addition significantly increased C mineralization in all the soil layers. However, the soil CO2 release relative to control was more than twofold higher in 15–35 and 35–55 cm soil layers than the surface layer. Nitrogen additions significantly decreased C mineralization in 0–15 cm soil, increased in 35–55 cm and had minimal effects in the 15–35 and 55–75 cm layers. Different soil C dynamics in surface and subsurface soil layers found in our study contradict the general assumption that soil C dynamics may be treated similarly along different soil depths. 相似文献
9.
三峡库区4种库岸边坡的植被根系固土效应研究 总被引：1，自引：0，他引：1
选择三峡库区无植被、草丛、灌丛及林木覆盖的4种边坡,测量了土壤表层（0—15 cm）的抗冲和抗蚀增强值,并以10 cm为单位分层获取了土壤表层（0—50 cm）的根长密度、根系生物量、土壤含水量、田间持水量、抗剪强度等指标。结果表明:（1）灌丛边坡的抗冲与抗蚀增强值均最大,显著高于草丛和林木边坡;灌丛边坡的抗剪强度值较大,裸地在10—20 cm的土层急骤增大,然后随土层深度逐渐减小,林地在最深层有着最大值。（2）3种有植被覆盖边坡的根系均集中在30 cm的表层,根长密度随着土层深度而减小;草丛和灌丛的根生物量在各层间变化不明显,林木根生物量随土层加深而迅速减小;（3）裸地的土壤含水量随着土层深度而急剧增加,林木则呈相反趋势,草丛和灌丛的变化较为平缓;灌丛的田间持水量在各层间基本保持一致,草丛和林木随着土层的加深而降低,裸地的表层田间持水量较大;（4）灌丛边坡的土体最稳定,各指标在土壤各层间较为稳定,林木和草丛边坡也有一定的稳定性,无植被覆盖的边坡稳定性最差。 相似文献
10.
Rui Jiang Xiao Li Minghua Zhou Hui Jie Li Ying Zhao Jun Yi 《Soil Science and Plant Nutrition》2016,62(1):1-12
Plastic film mulching has commonly been used for adaptation to water scarcity and for increasing agricultural productivity on the semiarid Loess Plateau of China. However, the effect of plastic film mulching on cropland soil water and thermal regimes on the semiarid Loess Plateau of China is not well understood. This study simultaneously monitored the dynamics of the soil water content and the soil temperature with high resolution in a ridge cultivation system with plastic film mulching (RS) and a flat cultivation system without plastic film mulching (FS) during the maize (Zea mays L.)-growing season. We found that, in general, the soil temperature and soil water content were significantly different among the ridge under RS (RS-ridge), the furrow under RS (RS-furrow) and FS throughout the maize-growing season (P < 0.05). Plastic film mulching increased the near-surface soil temperature by approximately 1°C throughout the study period. RS significantly increased the soil water content during the dry period (May to June), especially within the middle soil layer (30–60 cm), compared to FS. The lowest monthly average soil water content was found at a depth of 30–60 cm layer in FS during the dry period (May and June). The water depletion was found within deeper (100–160 cm) soil layers in May but the water storage in the same layer of FS in June increased although it was the dry period, which differed from RS. The RS practices showed a longer period of water supply from the deeper soil layer (100–160 cm) in May and June for meeting maize water demands during the early growing stage rather than in only May for FS. During June (dry period), the water storage at a depth of 0–60 cm was greater in RS than in FS, and the reverse was true at a depth of 60–160 cm. The results indicate that the dry soil layer at a depth of 30–60 cm formed during June in FS likely reduced water movement from deeper layers to the topsoil layer, and hence constrained the availability of surface soil water for meeting maize water requirements during the early growing stage (dry period). Our study suggests that RS tends to significantly increase surface soil water availability by restraining the formation of a dry soil layer during the early maize-growth stage primarily under dry conditions, and thus enhances maize productivity in the semiarid Loess Plateau of China. 相似文献
11.
套作夏玉米根系数量与活性的空间分布及变化规律 总被引：6，自引：0，他引：6
本文在小麦‖早春玉米/夏玉米超高产种植体系下,研究了套作夏玉米根系数量与活性的空间分布及变化规律,主要结果:(1)套作夏玉米于开花期达到最大根深160cm左右,且120～160cm深层根量持续增长至蜡熟末期。(2)根系数量呈上多下少的T型分布,0～20、20～80、80～120及120～160cm土层分别为根系高密度区、中密度区、低密度区和稀密度区。0～20、20～40及40～80cm土层根量密度大致于开花灌浆期达到最大值,之后呈下降趋势;80～120cm及120～160cm土层分别于灌浆期和蜡熟末期达最大;0～160cm整体根量密度以灌浆期为最大。(3)根系活性在土体中与数量相反呈倒T型分布。随生育进程推进,不同土层根系活性呈小大小变化,并且根系最高活性位点呈下移趋势,拔节期以20～40cm土层最高、大口期和开花期以80～120cm最高、灌浆期和蜡熟末期以120～160cm最高。0～160cm整体根系平均以大口期活性最高。(4)根系TTC还原总量在土体中呈上高下低的T型分布,根据TTC还原总量和总量密度高低,0～20、20～120和120～160cm土层分别为高量高密度区、中量中密度区和低量低密度区。从动态看,120cm以上各土层根系TTC还原总量及总量密度于花期达最大值,120～160cm深层土壤于灌浆期达最大值。0～160cm整体根系的TTC还原总量及总量密度 相似文献
12.
Effective rooting depth, percolation water, and nitrate leaching in deeply developed loess soils of a water‐shortage area In 14 deeply developed loess soils, high amounts of mineral nitrogen (N) were measured within the first meter, whereas several nitrate depth profiles up to more than three meters resulted in low and medium nitrate values. The maximum depth of water uptake was measured in two years on four representative sites with regard to soil and crop properties. The maximum depth of water uptake was always considerably deeper than 200 cm, with a maximum of 290 cm (alfalfa). It is assumed that roots take up nitrogen even in this depth. The calculation of the effective rooting depth resulted in noticeably higher values (for wheat between 160 cm and 185 cm) than those given by the ”︁German Instructions for Soil Mapping” (AG Boden, 1994), the ”︁Regulations of the German Organisation for Water Management and Land Improvement” (DVWK, 1995) or the ”︁German Institute for Standardization” (DIN, 1998). As a result of low annual precipitation (normally less than 600 mm), only a minor part of the high amounts of nitrate within the root zone was leached into deeper soil layers. We conclude that it is not possible to predict the potential groundwater pollution with nitrate on the basis of the mineral N content in the first meter of the soil profile. 相似文献
13.
渭北旱塬管理措施对冬小麦地土壤剖面物理性状的影响 总被引：1，自引：1，他引：0
【目的】研究黄土高原旱作农业区不同施肥覆盖措施对冬小麦地0—40 cm土壤剖面物理性质的影响,可为保持良好的土壤物理性状,探求适合渭北旱塬可持续的田间管理措施提供参考。【方法】基于设在渭北旱塬15年的田间定位试验,选取NP (N 150 kg/hm^2+P 75 kg/hm^2)、NPK (NP+K 30 kg/hm^2)、NPB (NP+biochar 14.0t/hm^2)、NPFFT (NP配合地膜夏闲期覆盖)、NPFGT (NP配合地膜生育期覆盖)和NPFWT (NP配合地膜全年覆盖)共6个处理。于2017年冬小麦收获期采集剖面土样,对0—10 cm、10—20 cm、20—30 cm和30—40 cm土层土壤含水量、土壤容重、饱和导水率和水稳定性团聚体等相关土壤物理性质进行测定与分析。【结果】与NP相比,NPK处理降低了收获期0—20 cm土壤容重,增加了耕层土壤总孔隙度和0—40 cm土层> 2 mm水稳定性团聚体含量,0—10 cm土层> 2 mm水稳定性团聚体含量显著提高了1.3倍(P <0.05);NPB处理,收获期耕层土壤容重降低,土壤总孔隙度增加,表层土壤饱和导水率显著降低27.9%,剖面土壤含水量和> 2 mm水稳定性团聚体含量均增加,且表层> 2 mm水稳定性团聚体含量显著提高了1.0倍;NPFFT处理收获期剖面土壤含水量降低,耕层土壤容重增加,总孔隙度降低;NPFGT处理收获期耕层土壤容重和剖面土壤含水量均增加,耕层总孔隙度降低,剖面土壤饱和导水率降低,尤其表层显著降低60.2%;NPFWT处理收获期耕层土壤容重增加,总孔隙度降低,表层土壤饱和导水率降低,但10—40 cm土壤饱和导水率平均提高57.5%,剖面土壤含水量、> 2 mm水稳定性团聚体含量、平均重量直径和几何平均直径均增加。受当地传统耕作深度的影响,不同施肥覆盖措施对土壤容重、饱和导水率和孔隙度的影响主要集中在0—20 cm土层,对20—40 cm土层影响较小。【结论】在氮磷肥配施的基础上,增施钾肥、生物炭和地膜全年覆盖均有利于改善试验农田土壤物理性质,但从经济投入和对土壤物理性状改良程度方面考虑,增施钾肥和地膜全年覆盖这两种处理是保持渭北旱塬良好土壤剖面物理性质的有效措施。 相似文献
14.
Dr Dirk Knoche 《Archives of Agronomy and Soil Science》2013,59(4):477-483
Abstract Most waste rock dumps of Uranium mining in the Eastern German Ore Mountains near Schlema site are covered with an 80 cm compacted loam sublayer and a vegetated 20 cm top layer by mixing of compost and mineral soil (vol. 50%/vol. 50%). The cover is quite fertile and leads to a considerable reduction of water infiltration into the heaps. However, soil forming processes alter the physical properties of the cover affecting soil hydrology, stability and growth conditions. Within 6 years after placement self-compaction increased dry bulk density of the top soil (10 – 20 cm depth) from 1.15 – 1.35 g cm?3. As a consequence, the air filled macropores decreased from >20 vol.-% to 8 vol.-%, whereas the water storing medium pores increased by 9 vol.-%. In contrast, dry bulk density of the pre-compacted mineral sublayer remained unchanged at 1.72 g cm?3. Nevertheless, even in 30 – 60 cm depth, a significant increase in plant available water-holding capacity occurred. Initial soil dynamics are likely to improve the hydrological efficency and stability of the cover system. On the other hand, there is already some evidence for structural cracks and preferential water flow, which counteract the positive effects of self-consolidation and therefore requires further research. 相似文献
15.
Summary The use of vertical biopores by wheat (Triticum aestivum) seminal roots for easy access to the subsoil and the consequences for plant water supply and yield has been investigated by computer simulation. Parameters included were: biopore density and diameter, depth of cultivation and strength of the subsoil — all under a wide range of seasonal weather conditions. The model predicts that biopores add significantly to root penetration at depth, even at a density of 0.1% v/v of small, vertical pores, while 1.5% to 2.0% v/v can ensure maximum root penetration. When the growing season is shorter a larger number of biopores is needed to ensure timely root penetration to depth. With shallow tillage, biopores occur closer to the soil surface, and their importance is increased. Deeper root penetration invariably gives greater water uptake and transpiration, but may have a negative effect on grain yield, especially under the driest climatic conditions. An increase in early water use may result in less soil water being available during the grain-filling period. The effect of biopores on plant transpiration varies from year to year, depending on the amount of rain and its distribution in time, and on the amount of soil water stored at time of sowing. 相似文献
16.
Eduardo Miranda Janaina Carmo Eduardo Couto Plínio Camargo 《Land Degradation \u0026amp; Development》2016,27(6):1586-1594
The net effect of agriculture on soil carbon is not yet fully understood. While a number of studies on shallow profiles have been published, evidence suggests that carbon stock changes occur in deeper layers. In this study we analyzed the effect of agriculture in the Cerrado soil C looking at changes in seven different profile depths from 0 to 100 cm in a commercial grain farm. We also used isotopic techniques to distinguish between the original Cerrado C3 carbon and the C4 carbon derived from the grasses used in agriculture. At 0–5 cm depth C stocks significantly decreased with cultivation time. The C stock did not change significantly when it was calculated using the 0–10, 0–20, 0–30, 0–50 or 0–75 cm profile (p > 0·05) but increased with cultivation time when the profile considered was 0–100 cm (p < 0·05). A two‐source isotope model revealed that there was a significant increase in carbon derived from C4 grasses for all depths with cultivation time. Annual carbon sequestration rates for the upper 100 cm of soil were 1·1 Mg C ha−1 year−1 for total carbon and 0·8 Mg C4 C ha−1 year−1 for C4 carbon. The oldest area, with 23 years of cultivation, had a soil C stock increase compared to the native Cerrado soil of 17·6%. These findings suggest that commercial grain farms practices may increase soil C stock compared to native Cerrado soil, if a more complete soil profile down to 100 cm is used to assess C stocks. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
17.
In this study, we quantified the contribution of forest-derived carbon (FDC) to the soil organic C (SOC) pool along a natural succession from savanna (S) to mixed Marantaceae forest (MMF) in the Lopè National Park, Gabon. Four 1-ha plots, corresponding to different stages along the natural succession, were used to determine the SOC stock and soil C isotope composition (δ13C) to derive the FDC contribution in different soil layers down to 1 m depth. Besides, to investigate changes in SOC stability, we determined the 14C concentration of SOC to 30 cm depth and derived turnover time (TT). Results indicated that SOC increased only at the end of the succession in the MMF stage, which stored 46% more SOC (41 Mg C ha?1) in the 0–30 cm depth than the S stage (28.8 Mg C ha?1). The FDC contribution increased along forest succession affecting mainly the top layers of the initial successional stages to 15 cm depth and reaching 70 cm depth in the MMF stage. The TT suggests a small increase in stability in the 0–5 cm layer from S (146 years) to MMF (157 years) stages. Below 5 cm, the increase in stability was high, suggesting that FDC can remain in soils for a much longer time than savanna-derived C. In conclusion, the natural succession toward Marantaceae forests can positively impact climate change resulting in large SOC stocks, which can be removed from the atmosphere and stored for a much longer time in forest soils compared to savanna soils. 相似文献
18.
Soil water content (SWC) and soil temperature (ST) are important indicators of environmental change in permafrost regions. In this study, we conducted soil sampling at 89 locations in the Three Rivers Headwaters Region (TRHR) to investigate the individual and synergistic effects of environmental factors on SWC and ST. We used multivariable regression and random forest modelling to analyse the data. The results show that SWC and ST were higher in the southeast TRHR than in the northwest and higher in surface layers than deeper soil layers. The most important factors affecting SWC in the 0–20 cm and 20–40 cm soil layers were soil bulk density and precipitation, while bulk density was the most important factor in the 40–60 cm layer, and soil bulk density and steppe vegetation were the most important factors in the 60–80 cm layer. For ST, altitude, temperature and slope gradient were the drivers in the 0–20 cm surface layer, while altitude and temperature were the most critical drivers in the 20–40 cm, 40–60 cm and 60–80 cm layers. Overall, bulk density and altitude were the key environmental factors influencing SWC and ST values, respectively. The outcomes of this study provide valuable insights into the environmental factors that impact the SWC and ST in permafrost regions, which can guide decision-making processes for sustainable soil management in the context of climate change. 相似文献
19.
Purpose
The vertical patterns of soil carbon (C), nitrogen (N), and phosphorus (P) stoichiometry are still controversial, and relative contribution of their controlling factors also is rarely understood for the whole soil profile. This study aimed to assess the vertical variation of both C/N, N/P, C/P ratios and their determining factors along soil profiles in subalpine forests of the eastern Tibetan Plateau.Materials and methods
Soil samples at five depths (0–10, 10–20, 20–30, 30–50, and 50–100 cm) were collected from 132 forest sites to evaluate the vertical distribution of soil C/N, N/P, and C/P ratios. Eleven relevant environmental factors (e.g., altitude, latitude, longitude, soil pH, soil bulk density, relative stone contents, soil order, slope, position, forest type, and dominant tree species) were measured to examine their relative contribution on stoichiometric ratios within each soil layer using boosted regression tree (BRT) analysis.Results and discussion
Soil C/N, N/P, and C/P ratios consistently decreased with increasing soil depth. BRT models accurately predicted the soil C/N, N/P, and C/P ratios in the upper four layers (R 2 = 49–97 %). For soil C/N and N/P ratios, altitude associated with latitude had the highest contribution across five soil layers, while the contributions of soil pH and bulk density were significant within soil layers closer to the surface. Independently, soil bulk density and altitude were the most important factors of C/P ratios in 0–30- and 30–100-cm soil layers.Conclusions
This study indicated that soil C/N/P stoichiometric ratios, and the relative importance of their controlling factors, shifted within soil profiles across Tibetan Plateau forests. Further research will be needed to understand the regulatory mechanism of soil stoichiometry and biogeochemistry in response to environmental change at whole soil profiles.20.
Jelena Petrović Snežana Dragović Ranko Dragović Milan Đorđević Mrđan Đokić Mirjana Ćujić 《Journal of Soils and Sediments》2016,16(4):1168-1175