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1.
Soil bulk density (ρ b ) is one of the most important parameters in the study of agriculture and geotechnical engineering. Time domain reflectometry (TDR) has been used to accurately determine ρ b based on the relationships among ρ b , θ g , and dielectric constant (K). The objective of this study is to develop a simple and accurate TDR equation to measure soil bulk density. Laboratory measurements of soils with different textures were carried out to establish the TDR–bulk density equation, and then the performance of this improved equation was evaluated with independent soils in laboratory and field conditions. Results indicated that the established equation could provide accurate ρ b estimation, where the TDR–bulk density equation was associated with <5% error both under laboratory and field conditions. It indicated that in the study of tillage management and geotechnical engineering, the established equation could be employed as a useful reference method for bulk density measurement when using TDR.  相似文献   

2.
We studied the combined effects of reduced tillage and animal manure on soil structure and hydraulic conductivity (K) in the 2–10 and 12–20 cm layers in a loamy soil. The study was performed at the end of a 7‐yr field trial and included three tillage treatments (mouldboard ploughing until 25 cm depth: MP, shallow tillage until 12 cm depth: ST, no‐till: NT) and two fertilizer application treatments (mineral or poultry manure). Soil structure was assessed through bulk density (ρb), micromorphological and macropore‐space characteristics. K was measured in situ at ?0.6, ?0.2 and ?0.05 kPa. Untilled layers had a vermicular microstructure resulting from earthworm activity, whereas tilled layers displayed a mixture of crumb and channel microstructures. Untilled layers had the highest ρb and twice as much lower total macroporosity area (pores > 240 μm in equivalent diameter) than tilled layers, reflected by the smallest area of macropores 310–2000 μm in diameter and the smallest area of large complex macropores. K under untilled layers was 12–62% lower than that under tilled layers, but differences were statistically significant only at ?0.05 kPa in the 2–10 cm. No significant interaction between tillage and nutrient application treatments was detected for all properties. Compared with mineral fertilizer, poultry manure resulted in a similar ρb but 20% greater total macroporosity area and 30% higher K at ?0.2 kPa. Overall, the sensitivity of soil structure and K to poultry manure were relatively small compared with tillage. We suggest that cultivation practices other than animal manure application are needed to improve physical properties under reduced tillage.  相似文献   

3.
This study was conducted to investigate the impact of land use (dryland farming, grassland and irrigated farming) on bulk density, (ρb) and relative bulk density (ρb‐rel), and to study the relationships between ρb and ρb‐rel, respectively, and soil organic matter content (OM) and soil texture at 100 locations in calcareous soils of central Iran. The ρb–rel was expressed as the ratio of ρb to a reference bulk density, ρbef. By considering ρb‐ref an inherent soil property that is dependent on soil texture but not on OM, the combined effects of OM due to land use and compaction (due to agricultural machinery) on the degree of compactness could be explored. Multiple linear regression was used to derive pedotransfer functions for predicting ρb and ρb‐rel. It was found that ρb‐rel is strongly affected by OM, and a strong correlation was obtained between ρb‐rel and the ratio of OM to clay content. The predictive performance of the multiple regression models was poorest for irrigated farming, which might be explained by intensive soil disturbance by tillage in irrigated farming. The main effect of land use was on OM, and consequently, the degree of compactness was mainly controlled by OM. The greatest OM and least ρb‐rel were measured in irrigated farming. Dryland farming had the least OM and the greatest ρb‐rel.  相似文献   

4.
The development of pedotransfer functions offers a potential means of alleviating cost and labour burdens associated with bulk‐density determinations. As a means of incorporating a priori knowledge into the model‐building process, we propose a conceptual model for predicting soil bulk density from other more regularly measured properties. The model considers soil bulk density to be a function of soil mineral packing structures (ρm) and soil structure (Δρ). Bulk‐density maxima were found for soils with approximately 80% sand. Bulk densities were also observed to increase with depth, suggesting the influence of over‐burden pressure. Residuals from the ρm model, hereby known as Δρ, correlated with organic carbon. All models were trained using Australian soil data, with limits set at bulk densities between 0.7 and 1.8 g cm?3 and containing organic carbon levels below 12%. Performance of the conceptual model (r2 = 0.49) was found to be comparable with a multiple linear regression model (r2 = 0.49) and outperformed models developed using an artificial neural network (r2 = 0.47) and a regression tree (r2 = 0.43). Further development of the conceptual model should allow the inclusion of soil morphological data to improve bulk‐density predictions.  相似文献   

5.
A field calibration experiment was carried out on salt‐affected clayey soil in Syria, to compare the sensitivity to soil electrical conductivity (ECe), and bulk density (ρb) of two instruments for estimating soil moisture: the neutron probe (NP) and the Diviner 2000 capacitance probe (CP). The results showed that the values of the correlation coefficient of the calibration were decreased when the ECe and ρb values increased; this decrease was more pronounced for the Diviner 2000, indicating that it was more sensitive to ρb and ECe than the NP. When only scaled frequency was used in the fitted equation, the Diviner 2000 in wet soil underestimated soil water content significantly at all depths, but especially in the top layer, by up to 0.09 cm3/cm3 compared with gravimetric determinations. However, in dry soil, the Diviner 2000 overestimated the volumetric water content by up to 0.05 cm3/cm3 in the top 15 cm, and by 0.03 cm3/cm3 at 30‐45 cm depth. The performance of the neutron probe was better overall; using a factory calibration curve no significant differences were observed between NP estimates and the gravimetric values. Including both ρb and ECe in the calibration equations improved the fits, although the regression coefficient (R2) for the Diviner 2000 remained low.  相似文献   

6.
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7.
Abstract

While biofuel crops are widely studied and compared for their energy and carbon footprints, less is known about their effects on other soil properties, particularly hydrologic characteristics. Soils under three biofuel crops, corn (Zea mays), switchgrass (Panicum virgatum), and willow (Salix spp.), were analyzed seven years after establishment to assess the effects on soil bulk density (ρb), penetration resistance (PR), water-holding capacity, and infiltration characteristics. The PR was the highest under corn, along with the lowest associated water content, while PR was 50–60% lower under switchgrass. In accordance with PR data, surface (0–10 cm) bulk density also tended to be lower under switchgrass. Both water infiltration rates and cumulative infiltration amounts varied widely among and within the three crops. Because the Philip model did not fit the data, results were analyzed using the Kostiakov model instead. Switchgrass plots had an average cumulative infiltration of 69 cm over 3 hours with a constant infiltration rate of 0.28 cm min?1, compared with 37 cm and 0.11 cm min?1 for corn, and 26 cm and 0.06 cm min?1 for willow, respectively. Results suggest that significant changes in soil physical and hydrologic properties may require more time to develop. Soils under switchgrass may have lower surface bulk density, higher field water capacity, and a more rapid water infiltration rate than those under corn or willow.  相似文献   

8.
This study investigated the potential for visible–near‐infrared (vis–NIR) spectroscopy to predict locally volumetric soil organic carbon (SOC) from spectra recorded from field‐moist soil cores. One hundred cores were collected from a 71‐ha arable field. The vis–NIR spectra were collected every centimetre along the side of the cores to a depth of 0.3 m. Cores were then divided into 0.1‐m increments for laboratory analysis. Reference SOC measurements were used to calibrate three partial least‐squares regression (PLSR) models for bulk density (ρb), gravimetric SOC (SOCg) and volumetric SOC (SOCv). Accurate predictions were obtained from averages of spectra from those 0.1‐m increments for SOCg (ratio of performance to inter‐quartile (RPIQ) = 5.15; root mean square error (RMSE) = 0.38%) and SOCv (RPIQ = 5.25; RMSE = 4.33 kg m?3). The PLSR model for ρb performed least well, but still produced accurate results (RPIQ = 3.76; RMSE = 0.11 Mg m?3). Predictions for ρb and SOCg were combined to compare indirect and direct predictions of SOCv. No statistical difference in accuracy between these approaches was detected, suggesting that the direct prediction of SOCv is possible. The PLSR models calibrated on the 10‐cm depth intervals were also applied to the spectra originally recorded on a 1‐cm depth increment. While a bigger bias was observed for 1‐cm than for 10‐cm predictions (1.13 and 0.19 kg m?3, respectively), the two populations of estimates were not distinguishable statistically. The study showed the potential for using vis–NIR spectroscopy on field‐moist soil cores to predict SOC at high depth resolutions (1 cm) with locally derived calibrations.  相似文献   

9.
Abstract. Recent developments in in situγ ray spectrometry offer a new approach to measuring the activity of radionuclides such as 137Cs and 40K in soils, and thus estimating erosion or deposition rates and field moist bulk density (ρm). Such estimates would be rapid and involve minimal site disturbance, especially important where archaeological remains are present. This paper presents the results of a pilot investigation of an eroded field in Scotland in which a portable hyper pure germanium (HPGe) detector was used to measure γ ray spectra in situ. The gamma (γ) photon flux observed at the soil surface is a function of the 137Cs inventory, its depth distribution characteristics and ρm. A coefficient, QCs, derived from the forward scattering of 137Cs γ ray photons within the soil profile relative to the 137Cs full energy peak (662 keV), was used to correct the in situ calibration for changes in the 137Cs vertical distribution in the ploughed field, a function of tillage, soil accumulation and ρm. Based on only 8 measurements, the agreement between in situγ ray spectrometry and soil sample measurements of 137Cs inventories improved from a non significant r2=0.05 to a significant r2=0.62 (P<0.05). Erosion and deposition rates calculated from the corrected in situ137Cs measurements had a similarly good agreement with those calculated from soil cores. Mean soil bulk density was also calculated using a separate coefficient, QK, derived from the forward scattering γ photons from 40K within the soil relative to the 40K full energy peak (1460 keV). Again there was good agreement with soil core measurements (r2=0.64; P<0.05). The precision of the in situ137Cs measurement was limited by the precision with which QCs can be estimated, a function of the low 137Cs deposition levels associated with the weapons testing fallout and relatively low detector efficiency (35%). In contrast, the precision of the in situ ρm determination was only limited by the spatial variability associated with soil sampling.  相似文献   

10.
Saturated hydraulic conductivity (Ks) is one of the soil properties used most often to predict soil behavior and suitability for a variety of uses. Because of the difficulty in Ks measurement and its variability with depth and across the landscape, Ks is commonly predicted from other more easily evaluated properties including texture, clay mineralogy, bulk density, pedogenic structure and cementation. Of these, texture and pedogenic structure are most commonly used to estimate Ks, but the reliability of these estimates has not been evaluated for common soils in the Southern Piedmont of Georgia. Thus, the objectives of this study were to evaluate Ks for major horizons in soils and landscapes in the Georgia Piedmont and to relate Ks to morphological properties of these horizons. Ten sites across the region were selected, and 21 pedons arranged in three transects were described from auger holes and pits. For each pedon, Ks was measured in upper Bt horizons, at 140 cm below the surface (Bt, BC, or C horizon), and at a depth intermediate between the shallow and deep measurements (Bt, BC, or C horizon) with a constant head permeameter. The Ks of individual horizons ranged from 1 × 10− 8 to 2 × 10− 5 m s− 1. At six of 10 sites evaluated, clayey upper Bt horizons had higher Ks than deeper horizons with less clay. This difference was attributed to weaker structure in the deeper BC horizons. Structural differences did not explain all variation in Ks with depth, however. Other soil and landscape properties including parent material composition, colluvium on lower slope positions, C horizon cementation, and depth of soil development also affected Ks of horizons in these soils and should be used to better estimate Ks.  相似文献   

11.
石灰岩与白云岩坡地土壤饱和导水率对比研究   总被引：1，自引：0，他引：1  
[目的]对比研究不同下垫面特征和土地利用方式对两类坡地表层土壤性质及其土壤饱和导水率(Ks)的影响。[方法]以喀斯特地区不同岩性下垫面的石灰岩和白云岩两类坡地表层土壤为研究对象,采用Guleph稳定入渗仪和土壤分析的方法。[结果](1)石灰岩和白云岩表层土壤在受到放牧作用影响后,土壤均呈现显著退化趋势,其容重、黏粒含量增大,孔隙度、有机质含量降低。(2)石灰岩和白云岩两类坡地表层土壤在未受到人为干扰的自然植被条件下,由于表层岩溶带的发育,Ks都很高,平均值分别为328.6和257.2mm/h。其中,石灰岩坡地相比白云岩坡地,Ks具有更高的空间变异性,二者Ks变异系数变化范围分别为90.71%~95.62%和59.60%~67.32%。(3)受到放牧作用影响后,石灰岩和白云岩坡地表层土壤Ks相比自然植被状态下呈显著降低趋势,Ks分别降低52.2%和86.7%,白云岩坡地Ks降低程度大,高于石灰岩坡地。  相似文献   

12.
选取黄土丘陵区12种典型植被样地,通过测定各样地不同土层植物残体生物量、土壤容重、毛管孔隙度、非毛管孔隙度及饱和导水率,研究各指标随土层深度和植被类型的变化规律及其对土壤饱和导水率的影响。结果表明:(1)除容重随土层深度增加外,植物残体、毛管孔隙度、非毛管孔隙度和饱和导水率均随土层深度减少,其中植物残体大多集中于表层土壤(0—10 cm),占总残体生物量的51.4%～85.7%。(2)不同植被类型其植物残体及土壤物理性质存在显著差异,乔木林地植物残体、农耕地土壤容重、灌木林地非毛管孔隙度及饱和导水率均最大,而毛管孔隙度与不同土地利用类型间无显著差异。(3)饱和导水率随植物残体生物量密度(0—10 cm)和土壤容重呈幂函数减小,随毛管孔隙度和非毛管孔隙度呈幂函数增大;土壤容重(BD)和非毛管孔隙度(NCP)是影响土壤饱和导水率(K_s)的主要因素,且土壤饱和导水率可表示为两者的综合非线性方程(K_s=0.6BD~(-4.717)NCP~(0.203),P0.01,R~2=0.63,NSE=0.50)。此外,沙棘灌木林地平均饱和导水率最大,有利于降雨过程中土壤水分入渗,具有较强的水土保持功能。本研究结果可为黄土高原植被恢复生态水文效益评价提供理论依据。  相似文献   

13.
Tillage depth influences the soil–water–plant ecosystem, thereby affecting crop yield and quality. The effects of tillage depth on soil physical properties and sugarbeet (Beta vulgaris L.) yield and quality were evaluated. A field study composed of two tillage depths [10 cm, referred to as shallow (ST), and 20 cm, referred to as deep (DT)] was conducted on a Lihen sandy loam soil in spring 2007 at the Agricultural Research Service (ARS) irrigated research farm near Williston, North Dakota. Soil bulk density (ρb), gravimetric water content (θw), and saturated hydraulic conductivity (Ks) were measured three times during the growing season at four depth increments to 40 cm deep. Samples were taken approximately 0.5 m apart within the crop row of irrigated sugarbeet. Soil air-filled pore volume (εa) was calculated from soil bulk density and water content data. Soil penetration resistance (PR) was also measured in 2.5-cm increments to a depth of 35 cm. Roots were hand-harvested from each plot, and each sample consisted of the roots within an area consisting of two adjacent rows 1.5 m long. Soil ρb was greater in ST than in DT, whereas Ks was greater with DT than with ST. Soil PR was significantly greater in ST than in DT at the 0- to 20-cm depth. Soil θw and εa were slightly greater in DT than those under ST. Although tillage depth had no significant effect on sugarbeet population, root yield, or sucrose content, a small difference in sucrose yield between two depths of tillage may be attributed to reduced ρb, increased water intake, improved aeration, and increased response to nitrogen uptake under DT than under ST. It was concluded that tillage depth enhanced soil physical quality and had little effect on sugarbeet yield or quality.  相似文献   

14.
为了解落叶松人工林结构对土壤水文特性的影响,对黑龙江省尚志市帽儿山地区不同结构类型下落叶松人工林的土壤水分物理性质、贮水能力及入渗性能进行研究。结果表明：1）土壤密度平均值由大到小依次为均匀结构、六行结构、四行结构、二行结构,分别为1.33、1.22、1.19和1.10 g/cm^3,总孔隙度变化趋势与土壤密度相反,分别为26.36%、48.99%、54.49%、56.00%;2）初渗速率变化范围为1.20-2.27 mm/min,10℃时的渗透系数K10大小依次为二行结构（1.04 mm/min）〉四行结构（0.81 mm/min）〉六行结构（0.67 mm/min）〉均匀结构（0.61 mm/min）,30 min累计入渗量表现出相应的变化趋势;3）40 cm土层范围内,土壤的饱和贮水量在1 054.20-2 239.80t/hm^2之间,其中二行结构的土壤贮水量最大。因此,二行结构的落叶松人工林土壤水文效益较高,是落叶松人工林营建时的首选方式。  相似文献   

15.
Intensive agriculture (IA) is widespread in South Italy, although it requires frequent tillage, large amounts of fertilizers and irrigation water. We have assessed the efficacy of reversing IA to sustainable agriculture (SA) in recovering quality of a typical South Italy soil (Lithic Haploxeralf). This reversion, lasting from 2000 to 2007, replaced 75% of nutrients formerly supplied inorganically by farmyard manuring and reduced the tillage frequency. Several chemical and biochemical properties, functionally related to C and N mineralisation–immobilisation processes and to P and S nutrient cycles, were monitored annually from 2005 to 2007 in the spring. Reversing IA to SA decreased soil bulk density, almost doubled the soil organic matter (SOM) as favoured the immobilisation of C and N, increased most soil microbial indicators but decreased contents of nitrate, mineral N and K2SO4-extractable C. The K2SO4-extractable C/K2SO4-extractable organic N ratio suggested that substrate quality rather than the mass of readily available C and N affected biomass and activity of soil microflora. Also, the largely higher 10-day-evolved CO2–C-to-inorganic N ratio under SA than IA indicated that higher C mineralisation, associated with higher microbial biomass N immobilisation, occurred under SA than IA. Decreases in most soil enzyme activities under IA, compared to SA, were much higher than concomitant decreases in SOM content. Soil salinity and sodicity were always higher in IA than SA soil, although not critically high, likely due to the intensive inorganic fertilisation as irrigation waters were qualitatively and quantitatively the same between the two soils. Thus, we suggest that the cumulative small but long-term saline (osmotic) and sodic (dispersing) effects in IA soil decreased the microbial variables more than total organic C and increased soil bulk density.  相似文献   

16.
Field production of ornamental shrubs often results in significant topsoil removal and degradation of surface soil physical properties. Building soil organic matter through compost amendments is one way to ameliorate effects from topsoil removal in woody ornamentals production. We amended field soils with three composts to evaluate their effects on soil physical properties and shrub biomass production. Specifically, we applied either duck manure-sawdust (DM), potato cull-sawdust-dairy manure (PC) or paper mill sludge-bark (PMB) composts to a Plano silt loam soil using two application methods: 2.5 cm of compost incorporated into the top 15 cm of soil (incorporated-only) or 2.5 cm of compost incorporated plus 2.5 cm of compost applied over the soil surface (mulched). We grew three shrub species from liners: Spirea japonicum ‘Gumball’, Juniper chinensis ‘Pfitzeriana’, and Berberis thunbergia ‘Atropurpurea’. Shrub species and soil amendment treatments were established in triplicate in a randomized split plot design. Total soil carbon (TC), bulk density (ρb), aggregate stability, soil moisture retention capacity (MRC), volumetric moisture content (θv), and saturated hydraulic conductivity (Ksat) were measured over three years (1998 to 2000). We measured above and below ground shrub dry matter production at the end of the first (1998) and second (1999) growing seasons. Mulched treatments resulted in 15%-21% higher TC than the incorporated-only and no-amendment control treatments. Bulk density decreased with increasing TC contents. Greater aggregate stability and the formation of larger aggregates were related to increased TC. Field moisture retention capacity tended to be higher in the incorporated treatments compared to the mulched and nonamended control treatments. Compost amended treatments increased saturated hydraulic conductivity (Ksat) sevenfold over the nonamended control. There were no compost effects on shrub biomass until the second year of growth. Barberry was the only species to respond significantly and positively to compost application. Specifically, mulched DM compost produced 39-42% greater total Barberry biomass than the other compost treatments and the nonamended control. Our findings showed that compost effects on soil physical properties differed among composts and their subsequent effects on shrub growth were species specific.  相似文献   

17.
Purpose

The effect of uncontrolled grazing and unpredictable rainfall pattern on future changes in soil properties and processes of savanna ecosystems is poorly understood. This study investigated how rainfall amount at a gradient of 50%, 100%, and 150% would influence soil bulk density (ρ), volumetric water content (θv), carbon (C), and nitrogen (N) contents in grazed (G) and ungrazed (U) areas.

Materials and methods

Rainfall was manipulated by 50% reduction (simulating drought—50%) and 50% increase (simulating abundance—150%) from the ambient (100%) in both G and U areas. Plots were named by combining the first letter of the area followed by rainfall amount, i.e., G150%. Samples for soil ρ, C, and N analysis were extracted using soil corer (8 cm diameter and 10 cm height). Real-time θv was measured using 5TE soil probes (20 cm depth). The EA2400CHNS/O and EA2410 analyzers were used to estimate soil C and N contents respectively.

Results and discussion

The interaction between grazing and rainfall manipulation increased θv and C but decreased N with no effect on ρ and C:N ratio. Rainfall reduction (50%) strongly affected most soil properties compared to an increase (150%). The highest (1.241?±?0.10 g cm?3) and lowest (1.099?±?0.05 g cm?3) ρ were in the G50% and U150% plots respectively. Soil θv decreased by 34.0% (grazed) and 25.8% (ungrazed) due to drought after rainfall cessation. Soil ρ increased with grazing due to trampling effect, therefore reducing infiltration of rainwater and soil moisture availability. Consequently, soil C content (11.45%) and C:N ratio (24.68%) decreased, whereas N increased (7.8%) in the grazed plots due to reduced C input and decomposition rate.

Conclusions

The combined effect of grazing and rainfall variability will likely increase soil θv, thereby enhancing C and N input. Grazing during drought will induce water stress that will destabilize soil C and N contents therefore affecting other soil properties. Such changes are important in predicting the response of soil properties to extreme rainfall pattern and uncontrolled livestock grazing that currently characterize most savanna ecosystems.

  相似文献   

18.
Soil bulk density (ρ) is an important physical property, but its measurement is frequently lacking in soil surveys due to the time‐consuming nature of making the measurement. As a result pedotransfer functions (PTFs) have been developed to predict ρ from other more easily available soil properties. These functions are generally derived from regression methods that aim to fit a single model. In this study, we use a technique called Generalized Boosted Regression Modelling (GBM; Ridgeway, 2006 ) which combines two algorithms: regression trees and boosting. We built two models and compared their predictive performance with published PTFs. All the functions were fitted based on the French forest soil dataset for the European demonstration Biosoil project. The two GBM models were Model G3 which involved the three most frequent quantitative predictors used to estimate soil bulk density (organic carbon, clay and silt), and Model G10, which included ten qualitative and quantitative input variables such as parent material or tree species. Based on the full dataset, Models G3 and G10 gave R2 values of 0.45 and 0.86, respectively. Model G3 did not significantly outperform the best published model. Even when fitted from an external dataset, it explained only 29% of the variation of ρ with a root mean square error of 0.244 g/cm3. In contrast, the more complex Model G10 outperformed the other models during external validation, with a R2 of 0.67 and a predictive deviation of ±0.168 g/cm3. The variation in forest soil bulk densities was mainly explained by five input variables: organic carbon content, tree species, the coarse fragment content, parent material and sampling depth.  相似文献   

19.
土壤饱和导水率（Ks）是反映土壤入渗性能与土壤持水能力的重要参数，为探究流域尺度下土壤Ks的空间分布特征及影响因素，更好地掌握土壤水文过程与调节机理，选取晋西北黄土丘陵区朱家川流域横向梯度（上游、中游、下游）不同土地利用方式下的土壤（70个样点）为研究对象，采用定水头法测定土壤Ks，并获取样点地形因子和其他土壤理化性质，通过建立土壤Ks偏最小二乘回归模型（PLSR），分析影响土壤Ks空间分布格局的主要因素。结果表明：（1）除土壤容重和砂粒含量为弱变异外，区域土壤理化性质其余因子均为中等变异；土壤Ks在横向梯度下表现为上游 > 中游 > 下游；（2）不同土地利用方式下土壤Ks差异显著（P<0.05），由高到低顺序为林地 > 农地 > 草地；（3）林地（VIP=1.997）与草地（VIP=1.710）利用方式、土壤容重（VIP=1.548）、土壤有机质（VIP=1.323）、大团聚体（VIP=1.266）、粉粒含量（VIP=1.062）和黏粒含量（VIP=1.049）是土壤Ks变化的主要因素，林地利用方式影响程度最大。土地利用、土壤性质、地形因子均是影响黄土丘陵区土壤Ks空间分布的主要因素，是用来模拟预测土壤Ks空间分布的重要因子。  相似文献   

20.
Effects of charcoal production on soil physical properties in Ghana   总被引：15，自引：0，他引：15  
Charcoal production, widespread in Ghana like in other W African countries, is a major driver of land‐cover change. Effects of charcoal production on soil physical, including hydrological, properties, were studied in the forest–savannah transition zone of Ghana. Core and composite samples from 12 randomly selected sites across the width of Kotokosu watershed were taken from 0–10 cm layer at charcoal‐site soils and adjacent field soils (control). These were used to determine saturated hydraulic conductivity (Ksat), bulk density, total porosity, soil texture, and color. Infiltration rates, surface albedo, and soil‐surface temperature were also measured on both sites. The results showed that the saturated hydraulic conductivity of soils under charcoal kilns increased significantly (p < 0.01) from 6.1 ± 2.0 cm h–1 to 11.4 ± 5.0 cm h–1, resulting to a relative increase of 88%. Soil color became darkened under charcoal kilns with hue, value, and chroma decreasing by 8%, 20%, and 20%, respectively. Bulk density on charcoal‐site soils reduced by 9% compared to adjacent field soils. Total porosity increased from 45.7% on adjacent field soils to 50.6% on earth kilns. Surface albedo reduced by 37% on charcoal‐site soils while soil‐surface temperature increased up to 4°C on average. Higher infiltration rates were measured on charcoal‐site soils, which suggest a possible decrease in overland flow and less erosion on those kiln sites.  相似文献   

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