Infiltration characteristics of water in forest soils in the Simian mountains, Chongqing City, southwestern China

Spearman rank-correlation analysis and grey relational grade analysis were used to study infiltration characteristics of water in different forest soils in the Simian mountains, Chongqing City. The results indicate that the soil bulk density, contents of coarse sand, and porosity of macropores were significantly correlated with saturated hydraulic conductivity. Porosity of macropores and contents of coarse sand were positively correlated with soil saturated hydraulic conductivity and soil bulk density negatively. Based on the initial infiltration rate, the stable infiltration rate, time required for infiltration to reach a stable state, and cumulative infiltration, all of which are crucial parameters determining soil infiltration capacity, the results of grey relational grade analysis showed that the grey relational grades of the different forest soils were listed from high to low as broad-leaved forest (0.8031) > Phyllostachys pubescens forest (0.7869) > mixed conifer-broadleaf forest (0.4454) > coniferous forest (0.4039). Broadleaf forest had the best ability to be infiltrated among the four soils studied. The square roots of the coefficients of determination obtained from fitting the Horton infiltration equation, simulated in our study of forest soils, were higher than 0.950.We conclude that soils of broad-leaved forests were the best suited for infiltration processes of forestry in the Simian mountains. __________ Translated from Journal of Soil and Water Conservation, 2008, 22(4): 95–99 [译自: 水土保持学报]     

Impacts of fractal features of soil on moisture infiltration capacity of typical stands in Jinyun mountain of Chongqing city

The soil structure was expressed with fractal dimensions of particle size distribution (PSD), aggregate size distribution (ASD), and soil pore size distribution (SPD). The effect of soil fractal features on soil infiltration velocity and process was studied. The result of the fractal feature shows that fractal dimensions of PSD are obviously greater than those of ASD and SPD, and in different soil genetic horizons, the fractal dimension of ASD has the greatest variability, and shows a downtrend on the top-to-bottom genetic horizon. According to the soil infiltration process curve, the infiltration process was divided into three phases: (1) the initial phase (0–5 min), (2) the transition phase (5–30 min), and (3) the stable phase (30–180 min). In the initial phase of infiltration, the soil structure of soil genetic horizon A was the major influencing factor; in the transition phase of infiltration, the pore distribution of soil horizon AB and soil structure of horizon B were the major influencing factors; in the stable phase of infiltration, the soil structure of horizon C was the major influencing factor to the infiltration velocity. Soil infiltration process is influenced comprehensively by soil PSD, ASD, and SPD. In the overall soil water infiltration, the infiltration in shrub forest land was much faster than that in other land uses, and in the initial infiltration phase, arable land soil infiltration was much faster than that in forest land, and in the stable infiltration phase, the infiltration velocity in forest land was faster than that in arable land. __________ Translated from Journal of Beijing Forestry University, 2006, 28(3): 73–78 [译自: 北京林业大学学报]     

孟加拉国丘陵地带桔园和灌木林地土壤物理性质的比较评价

The physical properties of soil on two hill slopes of 35% and 55% in orange orchard cultivated by the Mro tribe of Chittagong Hill Tracts （CHTs） were evaluated and compared with those of bushy hill forests. Soil samples were collected from three different depths （0-5 cm, 5-15 cm and 15-30 cm）, digging three profiles in each land use for determining moisture content, organic matter content and particle density. Maximum water holding capacity, field capacity, dry and moist bulk density and porosity were determined only for the surface soils. Moisture content at all the soil depths was significantly higher （p≤ 0.05） in orange orchard than in forest on both the slopes. Orange orchard contained lower mean soil organic matter than forest on 55% slope, while it contained higher values on 35% slope compared to forest. The highest value of the above two properties was found at surface soil in both the land uses on both the slopes, decreasing with the increase of soil depth. On both the slopes maximum water holding capacity and porosity of surface soil and particle density at all soil depths were lower in orange orchard compared to those in forest. Field capacity values of surface soil did not show consistency in trend for the differences between the two land uses on both the slopes. Bulk density value of moist and dry surface soil was higher in orange orchard than in forest on both the hill slopes.     

Exotic Pinus carbaea causes soil quality to deteriorate on former abandoned land compared to an indigenous Podocarpus plantation in the tropical forest area of southern China

Soil properties under an exotic plantation (Pinus caribaea) and an indigenous plantation (Podocarpus imbricatus) were compared with adjacent secondary forests and abandoned land in the tropical forest areas of Jianfengling National Nature Reserve in Hainan province, southern China. The surface soil (0–0.2 m) under Pi. caribaea has higher bulk density, lower soil organic carbon, total N, total K, available N, microbial biomass carbon, and smaller soil microbial communities (as indicated by soil Biolog profiles) than under Po. imbricatus. Both land use types showed negative cumulative soil deterioration index (DI) compared to secondary forests. However, compared to abandoned land (DI = –262), the soil quality of Po. imbricatus showed improvement (DI = –194) while that of Pi. caribaea showed deterioration (DI = –358). These results demonstrated that these exotic pine plantations can significantly and negatively influence soil properties. By contrast, our results showed that adoption of indigenous species in plantations, or natural regeneration, can improve soil quality.     

云南松林土壤水文特征对计划烧除的响应

为探究计划烧除对云南松林土壤水文特征的影响,为计划烧除后森林生态系统服务功能评价提供依据,以云南省新平县实施多年计划烧除的云南松纯林为研究对象,设立20 m×20 m计划烧除样地和不进行计划烧除的自然对照样地各3块。2019年2月实施计划烧除作业,进行样地调查、火烧强度和枯落物储量调查,2020年6月采集土样,测定土壤物理、化学性质和土壤入渗性能。结果表明,计划烧除后土壤容重增加且在0~10 cm土层差异显著;毛管孔隙度和总孔隙度减少但差异不显著;有机质减少并在0~20 cm土层差异显著。计划烧除后土壤自然含水率、饱和持水率、毛管持水率和田间持水量减少但差异不显著;吸湿水量减少并且在0~20 cm土层差异显著。计划烧除后土壤初渗速率、土壤平均入渗速率和土壤稳定入渗率减少;土壤初渗速率和平均入渗速率在不同样地0~20 cm土层差异显著。计划烧除对土壤稳定入渗率的显著影响因素为土壤容重、孔隙度、有机质和饱和持水率。说明计划烧除后云南松林土壤持水性能下降,入渗性能下降,对于入渗性能的影响主要是源于土壤理化性质的改变。     

不同退耕还林模式对土壤修复作用的研究——以甘肃省庆阳市为例

以甘肃省庆阳市为例,探讨了退耕还林对土壤理化性质的影响,结果表明:坡耕地退耕后,有机质和营养元素的含量渐趋恢复,土壤容重、pH值减小,土体中团聚体的数量增大,土壤结构不断得到改善。其中刺槐×沙棘混交林地速效养分丰富,粘粒和≥0.25mm水稳性团聚体的数量大;侧柏×沙棘混交林地则酸性强,容重低,≥50μm的微团粒含量较高。刺槐×沙棘混交林对土壤的修复作用明显强于侧柏×沙棘混交林。     

The role of land tenure in conservation of tree and shrub species diversity in miombo woodlands of southern Malawi

Biodiversity is declining throughout southern African miombo woodlands due to poor land use practices that are detrimental to soil, vegetation and habitat. We aimed at examining tree and shrub species diversity and distribution in Uapaca kirkiana-dominated woodlands under three land tenure types; forest reserves, customary and leasehold land. The study was conducted at different forest sites within similar agroecological zone in southern Malawi. Study sites were located at a range of altitudes between 900 and 1,200 m a.s.l. Three circular plots each with 32.60 m radius were established at each study site to sample tree and shrub species composition, structure and distribution under three land tenure types. We found that forest reserves had higher species diversity with an average of 16 tree families, 27 genera and 34 species as compared to only 10 tree families, 6 genera and 6 species on customary forest lands. Comparisons of diameter at breast height size class distributions showed that customary land had significantly low numbers of small (5.0–10.0 cm) and very large (≥30 cm) diameter classes suggesting lower levels of regeneration and high rate of anthropogenic activities. The high species diversity and richness in forest reserves and leasehold land indicate high potential for protected lands to restore tree species diversity. It is concluded that levels of human activities as influenced by land tenure type reduce tree species diversity, composition and distribution at the different sites, and this confirms the hypothesis that open access lands are not compatible with conservation of tree and shrub species diversity because of high anthropogenic activities.     

不同施肥处理对杉木林土壤水源涵养功能的影响

[目的]林地土壤容重、孔隙度、蓄水性指标和土壤渗透性能反映土壤水源涵养功能大小,以连续施肥6 a的杉木林地为研究对象,研究不同处理的氮、磷肥对杉木林地土壤水源涵养功能的影响,为施肥杉木林地科学经营和水源涵养提供依据.[方法]对杉木林地进行不同的施肥处理:CK、N1(50 kg·hm-2a-1)、N2(100 kg·hm...     

Water infiltration and hydraulic conductivity in sandy cambisols: impacts of forest transformation on soil hydrological properties

Soil hydrological properties like infiltration capacity and hydraulic conductivity have important consequences for hydrological properties of soils in river catchments and for flood risk prevention. They are dynamic properties due to varying land use management practices. The objective of this study was to characterize the variation of infiltration capacity, hydraulic conductivity and soil organoprofile development on forest sites with comparable geological substrate, soil type and climatic conditions, but different stand ages and tree species in terms of the effects of forest transformation upon soil hydrological properties. The Kahlenberg forest area (50 km northeast of Berlin in the German northeastern lowlands) under investigation contains stands of Scots pine (Pinus sylvestris) and European beech (Fagus sylvatica) of different age structures forming a transformation chronosequence from pure Scots pine stands towards pure European beech stands. The water infiltration capacity and hydraulic conductivity (K) of the investigated sandy-textured soils are low and very few macropores exist. Additionally these pores are marked by poor connectivity and therefore do not have any significant effect on water infiltration rate. Moreover, water infiltration in these soils is impeded by their hydrophobic properties. Along the experimental chronosequence of forest transformation, the thickness of the forest floor layer decreases due to enhanced decomposition and humification intensities. By contrast, the thickness of the humous topsoil increases. Presumably, changes in soil organic matter storage and quality caused by the management practice of forest transformation affect the persistence and degree of water repellency in the soil, which in turn influences the hydraulic properties of the experimental soils. The results indicate clearly that soils play a crucial role for water retention and therefore, in overland flow prevention. There is a need to have more awareness on the intimate link between the land use and soil properties and their possible effects on flooding.     

冀北山地桦木林土壤水分物理性质研究

以4种不同桦木组成比例的林分类型为研究对象,比较其土壤水分-物理性质,结果表明:土层深度与容重呈正相关,落桦混交林土壤容重最大(1.14g/cm~3),桦木混交林最小(1.00g/cm~3);土壤孔隙度整体规律基本一致,随土层深度增加而减小,土壤毛管孔隙度、非毛管孔隙度、土壤总孔隙度均是黑桦纯林最大,分别为45.0%、9.6%、53.6%;土壤持水量(除桦木混交林规律不明显外)整体规律基本一致,随土层深度的增加而减小,土壤毛管持水量均值桦木混交林最大(43.2%),土壤最大持水量均值黑桦纯林最大(49.3%);土壤入渗速率与时间呈幂函数关系,初渗速率和稳渗速率规律一致,均是桦木混交林最大、桦杨混交林最小。     

Vertical distribution characteristics of soil organic carbon content in Caohai wetland ecosystem of Guizhou plateau,China

We selected four kinds of land use types from Caohai wetlands of Guizhou plateau (a total number of 32 soil profiles) to study the distribution characteristics of organic carbon content in soil. With different ways of land use, the organic carbon content of soil profiles and organic carbon density show the tendency of decreasing firstly and then increasing from top to bottom. With the increase of depth, the vertical difference becomes smaller first and then starts increasing. Land reclamation reduces the soil organic carbon content and density, changing its distribution structure in topsoil. The average content of organic carbon in Caohai wetlands are as follows: lake bed silt > marsh wetland > farmland > woodland, the average organic carbon content of lake bed silt, marsh wetland, farmland and woodland are 16.40, 2.94, 1.81 and 1.08 %, respectively. Land reclamation reduces the organic carbon content of soil, therefore the conversion of cultivated lands to wetlands and the increase of forest coverage will help to fix the organic carbon in soil and increase its reserves.     

不同林龄鹅掌楸人工林土壤团聚体及其有机碳状况

[目的]研究鹅掌楸人工林土壤团聚体及其有机碳状况,为合理经营鹅掌楸人工林、促进林业可持续发展提供依据.[方法]以不同林龄鹅掌楸人工林(幼龄林、中龄林、成熟林)土壤为研究对象,通过野外调查和室内分析,测定各粒级土壤团聚体及其有机碳含量,分析土壤团聚体稳定性主要指标即平均重量直径(MWD)、几何平均直径(GMD),阐明土壤...     

Sand-fixing effects of Caragana microphylla shrub in Horqin sandy land, North China

In the semi-arid Horqin sandy land of north China, Caragana microphylla, a leguminous shrub, is the dominant plant species and is widely used in vegetation reestablishment programs to stabilize shifting sand. The sand-fixing effects of 6-and 11-year-old C. microphylla plantations were studied. The results showed that: 1) the wind velocity and sand transport rate in the plantation were less than those in dunes; 2) the air temperature in the plantation was lower than those in dunes. Relative humidity was higher and the soil temperature was lower, which benefits plant growth; 3) the physical and chemical characteristics of soil were improved to some extent over age. The porosity and percentage of tiny sand (diameter 0.05–0.1 mm) and clay particle (diameter < 0.05 mm) increased, bulk density in surface soil decreased, and saturated water-holding capacity improved. Organic C, total N, available N and available K content increased gradually, and soil fertility was enhanced. __________ Translated from Journal of Soil and Water Conservation, 2007, 21(1): 84–87 [译自: 水土保持学报]     

Development of GIS-based FUSLE model in a Chinese fir forest sub-catchment with a focus on the litter in the Dabie Mountains,China

Land use plays an important role in soil loss and other environmental problems. Correct prediction of soil loss from different types of land use is very important to land use policy making in the Dabie Mountains, China. Field observations of water and soil loss were carried out in the Shangshe catchment in four types of land use in 1999–2002. This paper reports the study of soil loss in the sub-catchment of Chinese fir forest.     

Pasture or permanent crops after slash-and-burn cultivation? Land-use choice in three Amazon colonies

Land use was examined in three settlements – Pedro Peixoto in Acre and Theobroma in Rondonia, Brazil, and Pucallpa, in Peru. Research aimed at characterizing the differences in land use after initial slash-and-burn, and presenting hypotheses to assess the feasibility of improved land uses. Settlers in the Amazon practice slash-and-burn agriculture in forest lands to produce annual crops. After cropping, lands are converted to pasture, or planted with perennial crops, or fallowed in anticipation of future annual crop production. Land use after slash-and-burn cultivation in forest lands differed among the colonies examined. Whereas colonists in Pedro Peixoto converted lands to pasture for cattle production, settlers in Theobroma adopted a strategy encompassing both dual-purpose (milk and meat) cattle and perennial crop production. The more heterogeneous settlers in Pucallpa, who included small-scale cattle ranchers and riverine and forest slash-and-burn farmers, gave more importance to perennial crops. Hypotheses are suggested regarding the described land use differences, and implications for the adoption of agroforestry are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Soil compaction by grazing livestock in silvopastures as evidenced by changes in soil physical properties

Livestock, pasture, and timber trees are intimately interrelated in silvopastures. Most silvopasture research to date has focused on forage/animal/tree interactions, with less attention paid to animal/soil interactions in silvopastures. While a considerable body of work has been devoted to understanding the effects of livestock trampling on plants and soils in pastures, less has been done for livestock grazing in forests, and even less is available for silvopastures. Three replications of Douglas-fir forest, Douglas-fir/subclover pasture/sheep silvopasture, and subclover/sheep pasture were established in 1989 near Corvallis, Oregon USA. Pastures and silvopastures were grazed each spring during 1990–2001. These plots were sampled in 2002, after 11 years of grazing, and again in 2004 following 2 years without grazing. Soil in the silvopastures had 13% higher bulk density and 7% lower total porosity than those in adjacent forests in 2002. Most of the difference in total porosity was air-filled pores. Average water infiltration rate was 38% less in silvopastures than in forests, however total water stored in the top 6 cm of soil at field capacity was similar. Soil bulk density, total porosity, and air-filled pore space was similar for forests, pastures, and silvopastures after 2 years without livestock grazing. The infiltration rate of silvopasture soils in 2004 had increased to be similar to those of forests in 2002, however, forest soil infiltration rates also increased and continued to be higher than those of silvopastures. Plant production was not sensitive to changes in any of the soil parameters measured. Although livestock grazing did change soil infiltration rates, soil bulk density, and soil porosity, the effects were quickly reversed following cessation of grazing and had little detrimental effect on silvopasture forage or tree production.     

Rapid changes of soil properties following Caragana korshinski plantations in the hilly-gully Loess Plateau

In the semi-arid area of the Loess Plateau, Caragana korshinski, a leguminous shrub, is the dominant plant species widely used in vegetation rehabilitation programs. We collected soil samples in 8-and 18-year-old C. korshinski plantations to assess the effects of the shrub on the physical and chemical properties of the soil as well as enzyme activities. Soil samples were taken from two depths (0–20 and 20–40 cm) under the shrub canopy between shrubs. Results showed that shrub rehabilitation and development enhanced accumulation of organic C and total N. Carbon and nitrogen concentrations increased significantly with plantation age and had increased by 15.3–20.5-fold and 11.1–13.6-fold at 0–20 cm depth at the 18-year-old plantation compared with farmland soil. It was found that C. korshinski contributed significant enrichment of C and N contents under their canopies compared with farmland. The content of water stable aggregates in 18-year-old shrub land soil is higher than the 8-year-old shrub land, and the big aggregates (>5 mm) increased for the most part, by 67.4% and 59.0% in different layers, respectively. The contents of aggregates of over 0.25 mm in two shrub land soils in the upper layer (0–20 cm) increased by 4.6% and 14.1% compared with farmland. It indicates that C. korshinski afforestation can increase the content of aggregates. C. korshinski plantation can accelerate the increase of soil urea activity and invertase activity, respectively, especially in the upper layer. __________ Translated from Scientia Silvae Sinicae, 2006, 42(1): 70–74 [译自: 林业科学, 2006, 42(1): 70–74]     

然林及坡耕地转变为巨桉林后土壤抗蚀性变化

以川西低山区天然林及其人工更新形成的1年生（Ⅰ1）、2年生（Ⅰ2）和3年生（Ⅰ3）巨桉林,坡耕地及其退耕形成的1年生（Ⅱ1）、2年生（Ⅱ2）和3年生（Ⅱ3）巨桉林为研究对象,研究土壤抗蚀性变化。结果表明：天然林转变为巨桉林后土壤水稳性团聚体平均重量直径、结构性颗粒指数、团聚状况和团聚度降低,土壤不稳定团粒指数、分散率、侵蚀系数和受蚀性指数增加;相反,坡耕地转变为巨桉林后土壤水稳性团聚体平均重量直径、结构性颗粒指数、团聚状况和团聚度增加,土壤不稳定团粒指数、分散率、侵蚀系数和受蚀性指数降低。土壤抗蚀性综合主成分值呈现出天然林〉Ⅰ1〉Ⅰ3〉Ⅰ2及坡耕地〈Ⅱ1〈Ⅱ2〈Ⅱ3变化规律。说明天然林改为巨桉林后土壤抗蚀性会有所降低,但随着种植年限的增加土壤抗蚀性有上升趋势,而坡耕地改为巨桉林后土壤抗蚀性随种植年限的增加而增加。     

Effect of forest vegetation on runoff and sediment production in sloping lands of Loess area

According to fixed-position data for 1985–2003 from nine runoff plots of Caijiachuan watershed which lies in Jixian County of Shanxi Province in Loess area, this paper studied the relationship between vegetation and runoff and sediment production in sloping lands in detail, which helps to provide scientific basis for vegetation re-construction and studies on environmental transformation of water and sediment in watersheds of Loess area. Although, many study results testify that forest vegetation has an important function in soil and water conservation and cutting runoff, the effect of vegetation on runoff and sediment transmission is complicated, and this needs to be studied in depth. The results of the paper showed the following. Firstly, the natural secondary forest performs better function of soil and water conservation than artificial Robinia pseudoacacia forest, and runoff and sediment produced in the former in individual rainfall were 65%–82% and 23%–92% of those produced in the latter. At the same time, better correlative relationship between runoff and sediment production and rainfall and rainfall intensity were testified by multiple regression, but the correlation decreased gradually with the increase of canopy density of forest. Secondly, the difference of runoff and sediment production in several land use types was very distinct, and the amount of runoff and sediment produced from Ostryopsis davidiana forest and natural secondary forest were the least, and runoff and sediment produced from in artificial Robinia pseudoacacia forest and Pinus tabulaeformis forest were 5-fold as much as those from O. davidiana forest. Besides, runoff and sediment produced in mixed planting of apple trees and crops were 16.14-fold and 2.96-fold than those of O. davidiana forest, respectively, but the amount decreased obviously after high-standard soil preparation in the case of the former. Thirdly, based on gray cognate analyses of factors affecting runoff and sediment production in sloping land, the factors of stand canopy density and herb and litter biomass were the most significant ones, whose gray incidence degree exceeded 0.6. Therefore, mixed forest with multi-layer stand structure and shrub forest should be developed in vegetation re-construction of Loess area, which will help to increase coverage and litter thickness in order to cut down the runoff and sediment dramatically in sloping land. __________ Translated from Chinese Journal of Applied Ecology, 2005, 16(9): 1,613–1,617 [译自: 应用生态学报, 2005, 16(9): 1,613–1,617]     

Effect of conversion of farmland to forest or grassland on soil erosion intensity changes in Yanhe River Basin, Loess Plateau of China

Dynamic changes of soil erosion affected by conversion of farmland to forest or grassland in the Yanhe River Basin were analyzed based on the revised universal soil loss equation (RUSLE). The RUSLE variables were selected and calculated reasonably using the GIS technique. Results show that: 1) After the conversion of farmland to forest or grassland, soil erosion decreased greatly. Compared with soil erosion in period of 1986 to 1997, the soil erosion amount had been reduced on the average by 30.6% by 2000; 2) Of the different land uses, slope farmland, especially the steep slope land had the greatest impact on soil erosion. The conversion of forest or grassland was the main driving force for the reduction of soil erosion; 3) In the short term, soil erosion was mainly controlled by C-factor, implying that the adjustment of land use structure might be an effective approach to reduce soil erosion. __________ Translated from Science of Soil and Water Conversation, 2007, 5(4): 27–33 [译自: 中国水土保持科学]