广东省山区土壤有机碳密度特征及空间格局

利用广东省第二次土壤普查的223个典型土壤剖面特征数据和1:20万广东省土壤类型图,在GIS技术的支撑下,对广东省山区土壤0—20cm和0—100cm的土壤有机碳密度特征及空间格局进行分析.结果表明,广东山区土壤有机碳平均密度0—20cm为29.23tC/hm2,0—100cm为100.31tC/hm2;不同土壤类型其有机碳密度差异明显,0—20cm山地草甸土最高,为72.38tC/hm2,0—100cm硫酸盐土最高,为237.58tC/hm2,山区主要土壤类型的有机碳密度差异表现为赤红壤(25.61、86.60tC/hm2)<水稻土(28.94、90.82tC/hm2)<红壤(31.59、110.61tC/hm2).两种土层厚度的有机碳密度均呈现出北部高于南部、粤北山区高于粤东山区和粤西北部山区的态势,土壤有机碳密度随海拔高度的上升而增大,但海拔1200m以上的山地增幅明显减缓.气候特征和海拔高度决定了广东山区土壤有机碳密度的总体分布格局,而土壤和土地利用类型的差异导致山区土壤碳密度格局变化更为复杂多样.

新疆阿勒泰山区土壤形成特征及其垂直分布

新疆阿勒泰山区土壤形成特征有有机物质积累特征、粘化特征、钙积特征、盐积特征和相应的化学组成及粘土矿物特征。ba值0．99～2．41，粘粒Sa 3．53～4．84，Saf 2．63～3．57，土壤淋溶风化程度不高，R2O3在山地棕色针叶林土、山地灰色森林土中略有移动，粘土矿物以蒙脱石、伊利石为主。本区山体高大，土壤垂直分布完整，东西差距显著，具有温带荒漠草原土壤垂直分布的典型特征，在干旱中温带的山地土壤中有代表性。

贵州山区土壤物理性质对土壤侵蚀影响的研究

分析研究了贵州山区主要土壤类型及其在不同利用方式下的土壤主要物理性质对土壤侵蚀的影响，认为：土壤物理性质是影响土壤侵蚀和土壤抗蚀力的内在因素。贵州山区土壤表现出明显的粗骨性土壤的特征，不同土地利用方式下的土壤物理性质具有显著的差异，林地、草地和台耕地的土壤物理性状良好，有效地减缓了土壤侵蚀的发生发展，能有效地发挥保持水土的作用；而大面积的农耕坡地和裸坡地的土壤物理性状极差，则促进了山区土壤侵蚀的发生发展，是引起土壤侵蚀的主要土壤因素。通过对比分析，提出评价山区土壤抗蚀性的主要指标，并得出不同土地利用类型的土壤抗蚀能力依次为：台耕地＞林地、草地＞坡耕地、裸坡地。

我国南方山区土壤资源的特点及其合理利用

我国南方的浙、闽、赣、皖、湘、鄂、粤、桂、云、贵、川、台等省(区),分布着大面积山地和丘陵,有“七山二水一分田”之称。这些南方山丘,除广东省的海南岛和雷州半岛,云南南部的西双版纳,台湾省的东南部属热带山丘外,其余均属亚热带山地丘。南方山地的自然条件优越,土壤资源丰富,生产潜力很大,是我国农林牧综合发展的基地。

中国亚热带山地土壤发生特性和系统分类研究进展

为了解亚热带山地成土环境下土壤形成规律和分类现状,推动中西部山地土壤发生学研究和土系建立,为山地土壤资源的可持续利用提供参考。综述了有关中国亚热带山地土壤的发生发育特性及其系统分类的研究资料,包括中国亚热带山地的主要地球化学过程和成土过程特点,亚热带山地土壤分类的主要诊断层、诊断特性和诊断现象以及高级分类单元的垂直分布规律,基层分类单元的主要诊断指标。在此基础上,展望了亚热带山地土壤系统分类研究值得重视的4个方面:(1)深入理解亚热带山地土壤的地球化学和成土过程;(2)建立中国亚热带典型山地土壤的代表性土族、土系,检验和完善现有基层分类单元的诊断指标体系;(3)强化山地土壤系统分类中分析指标和数据标准化意识;(4)重视薄片微形态、现代仪器分析和计算机新技术的应用。

陕北土石山区枣树优质丰产栽培技术

陕北黄河沿岸土石山区土壤贫瘠、植被稀少、水土流失严重，地上地下可开发资源较少，但枣树以其同有的抗寒、抗旱、耐瘠薄特性，在这里生生不息几千年，目前已成规模化发展。笔者总结了该区域枣树优质丰产栽培技术，希望对枣农有所帮助。

浅谈山区防雷工程接地体的设计与施工

雷电是大自然的一种放电现象,闪电又分云闪和地闪,其中云地闪约占20%,云地闪造成大量人畜伤亡,建筑物、电器和微电器的损毁。所以,防雷装置的性能优劣至关重要,特别是接地技术。防雷工程中的接地体是保护各类电子设备和建筑物的关键,若接地体方法不对、不按技术规范要求、不考虑山区土壤电阻率大等具体情况,将起不到大地泄电的作用,相反还会造成干扰和地电位反击而破坏电子设备及建筑物。

Spatial interpolation method based on integrated RBF neural networks for estimating heavy metals in soil of a mountain region

A novel spatial interpolation method based on integrated radial basis function artificial neural networks （IRBFANNs） is proposed to provide accurate and stable predictions of heavy metals concentrations in soil at un- sampled sites in a mountain region. The IRBFANNs hybridize the advantages of the artificial neural networks and the neural networks integration approach. Three experimental projects under different sampling densities are carried out to study the performance of the proposed IRBFANNs-based interpolation method. This novel method is compared with six peer spatial interpolation methods based on the root mean square error and visual evaluation of the distribution maps of Mn elements. The experimental results show that the proposed method performs better in accuracy and stability. Moreover, the proposed method can provide more details in the spatial distribution maps than the compared interpolation methods in the cases of sparse sampling density.

Study on Soil Erosion Model Under Different Slopes in Southwest Karst Mountain Area

The aim was to further research soil erosion characteristics and accurately predict soil erosion amount in karst areas. Based on field surveys and research achievements available, yellow soils, which are widely distributed, were chosen as test soil samples and slope, rain intensity, vegetation coverage and bare-rock ratio were taken as soil erosion factors. Artificial rain simulation instruments （needle-type） were made use of to simulate correlation of rain intensity, vegetation coverage, and bare-rock ratio with soil erosion quantity. Furthermore, multiple-factor linear regression analysis, stepwise regression analysis and multiple-factor non-linear regression analy- sis were made to establish a multiple-factor formula of soil erosion modulus with dif- ferent slopes and select regression models with high correlation coefficients. The re- sults show that a non-linear regression model reached extremely significant level or significant level （0.692〈FF〈0.988） and linear regression model achieved significant lev- el （0.523〈FF〈0.634）. The effects of erosion modulus changed from decreasing to in- creasing and the erosion factors from high to low were rain intensity, vegetation cov- erage and bare-rock ratio when slope gradient was at 6~, 16~, 26~ and 36~. The mod- el is of high accuracy for predicting gentle slope and abtupt slope, which reveals correlation of erosion modulus with erosion factors in karst areas.

李子树优质壮苗培育技术要点

李子作为四川省丹棱县主要伏季水果之一,是山区农民实现了脱贫致富的主要途径。目前,全县李子栽培面积约0.3万hm^(2),其中脆红李栽培面积约0.2万hm^(2),主栽品种还有蜂糖李和五月脆等。生产上以毛桃枮为主,但随着生产面积的不断扩大,毛桃枮在一些山区土壤较粘重的地区已表现出明显的不适应性,出现根部病害加重、生长不良等症状。

河北邢台板栗产业发展现状及对策建议

板栗原产中国,是我国的特有树种,栽培历史悠久,在《诗经》《史记》中均有关于板栗的记载。河北省邢台县板栗产业传统优势明显,栽培历史已有千余年,唐朝时期的“板栗王”就位于板栗主产区浆水镇前南峪村。邢台县位于太行山东麓,山区土壤多为片麻岩,属于暖温带季风气候,四季分明,温差较大,年平均气温12~14℃,年无霜期173天,平均年降水量550~680毫米,有利于板栗的生长,是国内优质板栗主产区。

Water holding effect of subalpine dark coniferous forest soil in Gongga Mountain, China

Because of the distinction of soil property and humus content, soil water content is not ideal to indicate whether it is suitable to the growth of plant. Mainly based on the PF-a numerical value denoting the water regime of soil and connected with the growth of plant, the study combined the moisture percentage of soil with PF to research in quantity the interrelation between the moisture percentage and PF in different succession phases of subalpine dark coniferous forest in Gongga Mountain. The results showed that: (1) In the same PF value, the moisture percentage in humus horizon increased gradually with the devel-opment of the succession of the dark coniferous forest; The moisture percentage of over-mature forest was the highest and>mature forest>half-mature forest>young growth forest; (2) With the increase of soil depth, the soil bulk density increased and the moisture percentage decreased, but the difference in the percentage of moisture was not notable in different succession phases. (3) In different succession series, the vegetation affected the soil water characteristics by increasing the soil organic matter, improving the soil construction, receding the soil bulk density and enhancing the soil porosity; (4) The humus horizon of the dark coniferous forest soil has the highest water holding capability in this region.

Study on the Characteristics of Ecological Water Requirement in Maijishan Scenic Spot

[Objective] This study aimed to explore the characteristics of ecological water requirement in Maijishan Scenic Spot. [Methed] The characteristics of ecologi- cal water requirement in Maijishan Scenic Spot were analyzed based on,the data of soil humidity and meteorology of the spot. [Result] The result showed that the actual annual ecological water requirement in the spot was 678×10^6 m^3, and the proportion of soil water and evapotranspiration were 21% and 79%, respectively; the minimum annual ecological water requirement quota in the spot was 480.27×10^6 m^3, and the proportion of soil water and evapotranspiration were 16% and 84%, respectively; the minimum annual suitable ecological water requirement quota in the spot was 624.22×10^6 m^3, and the proportion of soil water and evapotranspiration were 18% and 82%, respectively. The precipitation was 614×10^6 m^3, and consumptive water surplus reached up to 78×10^6 m^3. The years when the precipitation was higher than the evapotranspiration accounted for 76%. Since 1980s, the evapotranspiration showed a linearly increasing trend. The precipitation was higher than the evapotranspiration from Jun. to Oct. and less than the evapotranspiration from Nov. to Dec. and Jan. to May. Evapotranspiration water requirement was regulated by soil water. The dis- parity between precipitation and evapotranspiration was huge in spring, thus having certain influence on waterfalls and streams in the spot. [Conclusion] The results of this study provided a basis for the rational use and long-term planning of the water sources in Maijishan Scenic Spot.

Soil Erosion and Its Basic Characteristics at Karst Rocky-desertified Land Consolidation Area: A Case Study at Muzhe Village of Xichou County in Southeast Yunnan, China

Xichou County of Wenshan Zhuang and Miao Autonomous Prefecture in southeast Yunnan is one of the karst mountainous areas in southwest China showing typical rock desertification. During this study, we set up three soil erosion contrast test spots at Muzhe Village, Benggu Township, Xichou County, which was the birthplace of the Xichou rock-desertified land consolidation mode. The three spots included the terrace land spot （already consolidated land）, sloping land spot （unconsolidated sloping land under rock desertification）, and standard runoff spot （bare land spot）. In 2007, a whole-year complete observation was conducted during the rainy season and ＂rainfall-erosion＂ data were obtained for 32 times. Our analysis showed that during the entire observation period, the number of the rainfalls that led to soil erosion accounted for 34.04% of the number of all rainfalls and the amount of the rainfalls that led to soil erosion accounted for 84.17% of the total amount of all rainfalls. The average erosive rainfall standard in the three test spots was 11.0mm, slightly higher than the lO mm standard that has been adopted all over China, but lower than the 12.7 mm standard of the US and the 13.0 mm standard of Japan. According to single-factor analysis, the soil loss in the sloping land spot （L2） and that in the bare land spot （L3） are correlated to certain extent to manyother factors, including the single precipitation （P）, rainfall intensity during the maximum ten minutes （Lo）, rainfall intensity during the maximum 20 minutes （I2o）, rainfall intensity during the maximum 30 minutes （I30）, rainfall intensity during the maximum 40 minutes （I4o）, and rainfall intensity during the maximum 6o minutes （I60）. Among these factors, they are of the highest relativity with I6o. According to double-factor analysis, both L2 and L3 are of good relativity with P and I60. According to multi-factor analysis, L2 and L3 are also of good relativity with seven rainfall indexes, namely, P, Ia （average rainfall intensity）, L10, 120, I30, 140, and I60, with their related coefficient R reaching 0.906 and 0.914, respectively. The annual soil losses in the three test spots are widely different： 1030.70 t/km2.a in the terrace land spot, which indicates a low-level erosion; 12913.22 t/km2.a in the sloping land spot （unconsolidated spot）, some 12.5 times than that in the terrace land spot, which indicates an ultra-high-level erosion; and 19511.67 t/km2-a in the bare land spot, some 18.9 times than that in terrace land spot, indicating an acute erosion. These figures fully show that the Xichou rock-desertified land consolidation mode plays a significant role in soil conservation.

Microclimate regimes following gap formation in a montane secondary forest of eastern Liaoning Province, China

In order to improve the understanding of the role of a canopy opening/gap on the physical environments in a secondary forest in Northeastern China, a case study was conducted in and around a small irregular gap in a montane secondary forest. The secondary forest, which was severely disturbed by human beings about 50 years ago, was dominated by Quercus mongolica and Fraxinus rhynchophyllaan. Temporal variation in photosynthetic photon flux density （PPFD）, air temperature （TA） at 10 cm above the ground, soil temperature （Ts） and soil water content （SWC） at top-layer （0-15 cm） and sub-layer （15-30 cm） were measured from May to September after the second year since the formation of the small gap （the ratios of gap diameter to stand height were less than 0.5） in 2006 respectively. Results indicated that the highest value of PPFD occurred at the northern edge of the gap, particularly at the beginning of the growing season in May. On sunny days, the highest value of PPFD appeared earlier than that on overcast days. Maximum and mean values of TAwere higher in the northern part of the gap, and the minimum values of TAwere at the southern edge of the gap. Soil temperature varied obviously in the gap with the range from 1 to 8 ℃. Maximum values of Ts occurred at the northern part of the gap, which was significantly correlated with the maximum values of TA （R = 0.735, P〈0.05）. SWC was higher in the top-layer （0-15 cm） than that in sub-layer （15-30 cm）, but the difference of them was not significant （p〉0.05）, which might be attributed to the small gap size and the effects of aboveground vegetations. From these results, the maximum of PPFD in the study area occurred at the northern part of the gap, which was consistent with the results observed in north hemisphere, but the occurrence time varied with the differences of the latitudes. The highest values of air and soil temperatures also occurred in the northern part of the gap because they were affected by the radiation. However, the variation of temperature in July was different from other months due to the influence of gap size. And the values of soil water content were neither higher in the gap in the wet season nor lower in the dry season, which might be affected by the gap size and topography the gap located. The variations of light, soil and air temperatures, and soil moisture in this small irregular gap might be related to the effects of the micro-site, which affects the regeneration of plant species.

Soil Organic Carbon Pools in Particle-Size Fractions as Affected by Slope Gradient and Land Use Change in Hilly Regions,Western Iran

This study was conducted to explore the effects of topography and land use changes on particulate organic carbon(POC),particulate total nitrogen(PTN),organic carbon(OC) and total nitrogen(TN) associated with different size primary particle fractions in hilly regions of western Iran.Three popular land uses in the selected site including natural forest(NF),disturbed forest(DF) and cultivated land(CL) and three slope gradients(0-10 %,S1,10-30 %,S2,and 30-50%,S3) were employed as the basis of soil sampling.A total of 99 soil samples were taken from the 0-10 cm surface layer in the whole studied hilly region studied.The results showed that the POC in the forest land use in all slope gradients was considerably more than the deforested and cultivated lands and the highest value was observed at NF-S1 treatment with 9.13%.The values of PTN were significantly higher in the forest land use and in the down slopes(0.5%) than in the deforested and cultivated counterparts and steep slopes(0.09%) except for the CL land use.The C:N ratios in POC fraction were around 17-18 in the forest land and around 23 in the cultivated land.In forest land,the silt-associated OC was highest among the primary particles.The enrichment factor of SOC,EC,was the highest for POC.For the primary particles,EC of both primary fractions of silt and clay showed following trend for selected land uses and slope gradients:CL> DF> NF and S3 > S2> S1.Slope gradient of landscape significantly affected the OC and TN contents associated with the silt and clay particles,whereas higher OC and TN contents were observed in lower positions and the lowest value was measured in the steep slopes.Overall,the results showed that native forest land improves soil organic carbon storage and can reduce the carbon emission and soil erosion especially in the mountainous regions with high rainfall in west of Iran.

Land use optimization for sustainable development of mountain regions of western Serbia

This study analyses the possibilities for optimal land use structure in mountainous areas of rural Serbia, which is faced with problems such as unfavorable terrain characteristics and inadequate land use patterns causing economic underdevelopment and increasing population migration. In the case of a small privately owned farm in Western Serbia, optimal land use pattern is determined using the linear programming model. The objective function-cost-effectiveness or soil erosion reduction, as well as constraints, are formulated using the benefit-cost ratio(BCR) for a 15-year production period and soil losses data calculated using the Universal Soil Loss Equation(USLE). The best results are achieved using the scenario with the aim to minimize soil erosion, considering the BCR in the constraints. This scenario is proposed since it was registered that the benefit for landowners would increase by five times, while the losses of land would decline about 80%. The sensitivity analysis of investments is performed to check whether the price variation affects the cost-effectiveness of proposed land use. Results show that market changes(nine cases are considered) do not lead to significant changes in land use allocation. Proposed land use pattern improves the environmental condition, strengthens the rural economy and thus offers the greatest potential for sustainable development of mountainous rural areas.

Elevation, Slope Aspect and Integrated Nutrient Management Effects on Crop Productivity and Soil Quality in North-west Himalayas, India

On farm bio-resource recycling has been given greater emphasis with the introduction of conservation agriculture specifically withclimate change scenarios in the mid-hills of the north-west Himalaya region（NWHR）. Under this changing scenario, elevation, slope aspect and integrated nutrient management（INM） may affect significantly soil quality and crop productivity. A study was conducted during 2009-2010 to 2010-2011 at the Ashti watershed of NWHR in a rainfed condition to examine the influence of elevation, slope aspect and integrated nutrient management（INM） on soil resource and crop productivity. Two years of farm demonstration trials indicated that crop productivity and soil quality is significantly affected by elevation, slope aspect and INM. Results showed that wheat equivalent yield（WEY） of improved technology increased crop productivity by -20%-37% compared to the conventional system. Intercropping of maize with cowpea and soybean enhanced yield by another 8%-17%. North aspect and higher elevation increased crop productivity by 15%-25% compared to south aspect and low elevation（except paddy）. Intercropping of maize with cowpea and soybean enhanced yield by another 8%-15%. Irrespective of slope, elevation and cropping system, the WEY increased by -30% in this region due to INMtechnology. The influence of elevation, slope aspect and INM significantly affected soil resources（SQI） and soil carbon change（SCC）. SCC is significantly correlated with SQI for conventional（R2 = 0.65＊）, INM technology（R2 = 0.81＊） and for both technologies（R2 = 0.73＊）. It is recommended that at higher elevation.（except for paddy soils） with a north facing slope, INM is recommended for higher crop productivity; conservation of soil resources is recommended for the mid hills of NWHR; and single values of SCC are appropriate as a SQI for this region.

Community Characteristics of Wild Fruit Forests Along Elevation Gradients and the Relationships Between the Wild Fruit Forests and Environments in the Keguqin Mountain Region ofⅠii

In this paper,the quantitative relationship between the wild fruit communities and direct environmental factors is discussed on the basis of detailed data on landscape scale habitats obtained through field vegetation investigation.The results from TWINSPAN and DCCA showed that:1) In the distribution sections of the wild fruit forest in the Keguqin Mountain region,the basic patterns characteristic of the different habitats are due to topographic factors,nutrients and moisture conditions;2) The elevation affected the most basic differentiation of plant communities in the study area,indicating that the elevation condition was the most important factor restricting the distribution of the wild fruit communities in the study area;3) The close relationship between the moisture content in the upper soil layer and the elevation reflected the influence of moisture conditions on both wild fruit and herb-layer communities;4) Nutrient differences not only indicated that the habitat conditions were different in themselves but also showed that the present nutrient conditions of the habitats were seriously affected by human activities.In summary,under complicated mountainous topographic conditions,the habitat conditions for the communities differed very significantly,and the combination of elevation,soil moisture content,total nitrogen,slope aspect,and pH value influenced and controlled the formation of community distribution patterns in the study area.

Distribution of Soil Nutrients in Arable Land of Tropical Hilly and Mountainous Area

[Objective] The aim was to explore spatial distribution characters of soil nutrients in arable lands of Hainan mountainous areas and provide references for soil nutrient management in tropical mountainous areas. [Method] The research took arable lands in Wuzhishan City as an example by field survey, sampling and lab analysis and investigated soil nutrients and distributions based on analysis of soil nutrient contents. [Result] The soils were dominated by acid soils, with pH of 5.1; soil nutrients were distributed in a non-uniform manner; contents of soil organic matter, available phosphorus, available potassium, as well as medium elements kept lower or moderate levels; effective copper and available zinc were rich. Local spe- cial climate, uneven distribution of parent material and non-uniform fertilization con- tributed to acid soils and unbalanced distribution of soil nutrients in Wuzhishan. [Conclusion] It is recommended to facilitate soil nutrient balance by promoting re- turning straws to farmlands and technical specification of balanced fertilization by soil testing as per nutrient distribution of arable lands in Wuzhishan City.