油茶造林经济效益的提升对策

油茶是广西的重要产业之一。为提高油茶造林经济效益,分析了当前广西苍梧县油茶种植与油茶造林实际情况,总结影响经济效益的因素,并从采用多元化油茶造林栽培手段、油茶垦复栽培与管理、油茶良种选择与应用、加大油茶造林宣传力度及做好油茶造林生产与规划5个方面提出建议。     

不同经营模式下毛竹林土壤水分物理性质比较

通过对建阳市黄坑镇毛竹笋用林、毛竹材用林、毛竹油茶混交林、毛竹杉木混交林、毛竹油桐混交林等5种林分类型的土壤水分物理性质差异的分析,结果表明:毛竹杉木混交林的土壤容重最小,其次是毛竹材用林、毛竹油茶混交林、毛竹油桐混交林.而毛竹笋用林的土壤容重最大.5种经营方式下毛竹林的总孔隙度的范围在50.80V%～69.75V%.表层土壤的最大持水量和毛管持水量的平均值呈现出毛竹杉木混交林>毛竹油茶混交林>毛竹材用林>毛竹笋用林>毛竹油桐混交林的规律.     

柳州地区的森林火灾与气象条件

柳州地区现有森林面积770多万亩,是广西的主要木材基地。用材林有松、杉、桉、竹等;经济林木有油茶、油桐等,其中油茶面积占全广西的五分之一,产量占全广西的三分之一;水果有柑桔、柚、梨、板栗、柿、李、桃、芭蕉、核桃、金桔,柳中、柳南有龙眼、荔枝;山区还有药材等特产。发展林业是本地区的一大优势。但是,多年来由于森林火灾的发生,给柳州地区林业生产的发展造成了障碍。据统计,     

经济林地水土保持措施探讨

<正> 一、概况 江西地处亚热带湿润气候区,水热杀件优越,具有大面积的山地丘陵资源,这为发展经济林提供了有利的条件。全省经济林种类繁多,主要有:猕猴桃、柑、桔、橙、柚、梨、桃、李、柿、葡萄、枇杷、板栗、枣、油茶、油桐、桑、茶叶、棕榈等。现有经济林面积110.13万ha,其中水果林1.12万ha、板栗林3.67万ha、油茶林97.2万心、油桐林1.6万ha、茶树5.59万ha和其它经济林0.95万ha。1989年全省生产水果22.97万t,茶叶1.91万t、板栗1753t、油茶籽17.2万t,油桐籽5916t、蚕茧1350t。 经济林建设对江西农林业的发展,农村经济结构的调整,对老区和贫困地区的经济建设有着重要的意义。但我省经济林多种植在红壤坡地,许多林地都未采取有效的水土保持措施,存在着不同程度的水土流失。经济林地的侵蚀形态主要是面蚀,花岗岩侵蚀区的撩荒地可能发展成为沟蚀,甚至出现崩岗侵蚀。造成经济林地水土流失的原因,一是建     

关于创建祁阳县油茶特色产业园的构想

根据国家油茶产业政策和湖南省祁阳县油茶产业特色,提出创建祁阳县油茶特色产业园的设想,分别从建设背景、建设目标、建设范围及规模、建设内容、保障措施等方面进行了阐述,以供探讨。     

紫色土的利用与水土保持

山地紫色土在湖南黔阳地区分布比较广泛,据调查多分布在溆浦、辰溪、麻阳、芷江及沅陵等县。紫色土发育于紫色页岩、紫色砂砾岩等母质上,地势多为丘陵地,坡度一般在10-20°,最大的也有50°以上的,自然植被生长稀疏,复盖度约在30-40%,也有的不到10%,一般生长一些茅草,灌木、松杉以及油桐、油茶等经济林,还有枣子、板栗等果木分布。     

酉阳县着力推进三大林业产业化建设

<正>一是青花椒产业。以重庆和信农业有限公司为龙头,新建青花椒基地0.1万hm2,累计建成青花椒种植基地1.2万hm2,建成占地200 hm2的青花椒科技园1个,投资1.8亿元建设青花椒精深加工厂,带动3万户农户增收致富。二是油茶产业。引进康友、英棋等油茶公司20家,累计建设油茶种植基地1万hm2,完成"康友源"、"金银     

人为水土流失的危害及其法洽手段

由开矿、筑路、修渠、建厂、建水电工程、引黄泥沙和毁林开荒、陡坡耕种等造成的人为水土流失,是非常严重的。它的危害主要有:土层变薄,地力下降,淤积水库,抬高河床;污染环境,破坏生态。防治措施,首先是加强法制,依法管护和治理,第二是保护和提高大地植被;第三是严格执行有关水土保持和环境保护的法规,第四是因地制宜,综合治理,第五是综合利用,减少堆积,第六是制定采犷和基建毁地的垦复措施,包括农业垦复、林业垦复、水源垦复和综合垦复。     

试论天目山气候生态与毛竹、茶叶资源优势

<正> 引言具有亚热带山地气候特色的天目山区山林资源丰富,主要出产有竹、木、茶、板栗、山核桃、油茶、油桐、药材等。其中遍及天目山的毛竹林和茶园在亚热带常绿植物中经济价值较高。毛竹是我国很重要的一类森林资源,用途十分广泛,竹笋又是人们喜爱的素食品。茶叶是有益于健康的饮料佳品。浙江的毛竹和茶叶在全国名列前茅,天目山是主要产地之一。近几年来,毛竹和竹笋等竹副产品的社会需要量有增无减;并且     

我国小品种特色油料产业现状与发展策略

芝麻、亚麻、油葵、油茶、油橄榄、红花、苏子、蓖麻、油桐等虽为我国小品种油料作物,但在世界上,我国却是这些作物的主要种植国之一。由于它们具有与大宗油料作物所不同的脂肪酸组成和生理活性物质,在食用油脂、营养食品、医疗保健、工业与能源油脂等加工方面具有重要的作用。该文对我国小品种特色油料的产业现状和存在问题进行了分析,初步提出今后的发展策略。     

日本北海道地区森林、牧场、草原和玉米田温室气体排放及模型研究

Information on the most influential factors determining gas flux from soils is needed in predictive models for greenhouse gases emissions.We conducted an intensive soil and air sampling along a 2 000 m transect extending from a forest,pasture,grassland and corn field in Shizunai,Hokkaido (Japan),measured CO 2 ,CH 4 ,N 2 O and NO fluxes and calculated soil bulk density (ρ b ),air-filled porosity (f a ) and total porosity (Φ).Using diffusivity models based on either f a alone or on a combination of f a and Φ,we predicted two pore space indices: the relative gas diffusion coefficient (D s /D o ) and the pore tortuosity factor (τ).The relationships between pore space indices (D s /D o and τ) and CO 2 ,CH 4 ,N 2 O and NO fluxes were also studied.Results showed that the grassland had the highest ρ b while f a and Φ were the highest in the forest.CO 2 ,CH 4 ,N 2 O and NO fluxes were the highest in the grassland while N 2 O dominated in the corn field.Few correlations existed between f a ,Φ,ρ b and gases fluxes while all models predicted that D s /D o and τ significantly correlated with CO 2 and CH 4 with correlation coefficient (r) ranging from 0.20 to 0.80.Overall,diffusivity models based on f a alone gave higher D s /D o ,lower τ,and higher R 2 and better explained the relationship between pore space indices (D s /D o and τ) and gases fluxes.Inclusion of D s /D o and τ in predictive models will improve our understanding of the dynamics of greenhouse gas fluxes from soils.D s /D o and τ can be easily obtained by measurements of soil air and water and existing diffusivity models.     

Fine-earth translocation by tillage in stony soils in the Guadalentin, south-east Spain: an investigation using caesium-134

Tillage erosion is increasingly recognised as an important soil erosion process on agricultural land. In view of its potential significance, there is a clear need to broaden the experimental database for the magnitude of tillage erosion to include a range of tillage implements and agricultural environments. The study discussed in this paper sought to address the need for such data by examining tillage erosion by a duckfoot chisel plough in stony soils on steep slopes in a semi-arid environment. Results of the investigation of coarse fraction (rock fragment) translocation by tillage in this environment have been presented elsewhere and the paper focuses on tillage translocation and erosion of the fine earth. Tillage translocation was measured at 10 sites, representing both upslope and downslope tillage by a duckfoot chisel plough on five different slopes, with tangents ranging from 0.02 to 0.41. A fine-earth tracer, comprising fine earth labelled with ¹³⁴Cs, was introduced into the plough layer before tillage. After a single pass of the plough, incremental samples of plough soil were excavated and sieved to separate the fine earth from the rock fragments. Translocation of the fine-earth tracer was established by analysing the ¹³⁴Cs content of the samples of fine earth. These data were used to establish translocation distances for each combination of slope and tillage direction. Translocation distances of the fine earth were not significantly different from translocation distances of the coarse fraction. For all sites, except uphill on the 0.41 slope, translocation distances were found to be linearly related to slope tangent. The soil flux due to tillage for each site was calculated using the translocation distance and the mass per unit area of the plough layer. For slopes with tangents <0.25, the relationship between soil flux and tangent was linear and the soil flux coefficient derived was 520–660 kg m⁻¹ per pass. This is much larger than the coefficients found in other studies and this high magnitude is attributed to the non-cohesive nature and high rock fragment content of the soil in this investigation. A second contrast with previous studies was found in non-linearity in the relationship between soil flux and tangent when steeper slopes were included. This was a product of variation in plough depth between the steepest slopes and the remainder of the study area. On the basis of the study it is suggested that an improved understanding of tillage erosion may be obtained by considering the dual processes of tillage detachment (mass per unit area of soil subject to tillage) and tillage displacement (equivalent to translocation distance per pass) in assessing, comparing and modelling tillage translocation. An improved model is proposed that recognises the complexity of soil redistribution by tillage, provides a framework for process-based investigation of the controls on tillage fluxes, and allows identification of potential self-limiting conditions for tillage erosion.     

The long-term effect of tillage on soil displacement of hilly areas used for growing wheat in Greece

Abstract. Tillage displaces large amounts of soil from upper slopes and deposits soil in lower landscape positions, greatly affecting productivity in these areas. The long-term effect of tillage on soil erosion was studied in four field sites growing mainly rainfed wheat. The soil loss from landscape positions with slopes, ranging from 3 to 28%, was estimated by: (a) comparing data of horizon thickness described at the same position at different times; and (b) using soil movement tracers added to the soil. Existing empirical relationships were used for estimating soil loss by tillage and runoff water, and loss in wheat biomass production. The experimental data showed soil losses of 0.4 to 1.4 cm yr^–1 depending on slope gradient, plough depth, and tillage direction. In two of the sites, soil depth has been reduced by 24–30 cm in a period of 63 years. The mean soil displacement of the plough layer (30 cm thick), measured by soil movement tracers, ranged from 31 to 95 cm yr^–1 depending mainly on slope gradient, corresponding to a rate of soil loss of 0.3 cm to 1.4 cm yr^–1. Soil eroded from the upper slopes was deposited on the lower slopes increasing soil thickness by 0.4 cm to 1.4 cm yr^–1. The application of empirical relationships, estimating soil loss by tillage and water runoff, showed that soil erosion at the field sites can be mainly attributed to tillage. The loss in wheat biomass production due to erosion was estimated at 26% on upper slopes for a period of 63 years, while a 14.5% increase in wheat production was estimated due to deposition of soil material in the lower landscape.     

Reassessment of tillage erosion rates by manual tillage on steep slopes in northern Thailand

Changing land-use practices in northern Thailand have increased tillage intensity. This study re-assesses the rate of tillage erosion by manual hoeing on steep slopes (17–82%) in northern Thailand. Previously collected soil translocation data during an on-farm tillage erosion experiment and additionally collected data during an on-farm tillage erosion survey have been analysed whereby a new calculation method (i.e. trapezoid tillage step) has been used. A comparison with previously collected data indicates that the trapezoid tillage step method and the tracer method are the most reliable methods to assess downslope translocation by manual tillage. Based on newly acquired understanding of the processes involved, soil fluxes by tillage erosion are quantified by linear functions for different slope gradient classes rather than one single diffusion-type equation for the whole slope range. For slope gradients smaller than 3%, soil fluxes are close to zero as farmers do not have a preferred tillage direction. For slope gradients between 3% and 70%, soil is tilled only in the downslope direction and soil fluxes range between 16 and 67 kg m⁻¹ tillage pass⁻¹. On slopes with gradients in excess of 70%, the angle of repose for soil clods is often exceeded resulting in a sliding down of the complete tilled top layer. These data are used to assess the soil flux for complete cropping cycles for the most dominant cropping systems in the highlands of northern Thailand: i.e. upland rice, maize, (soy) beans, cabbage and ginger. The on-site effects of tillage erosion will be very pronounced if parcels are short with respect to their slope length, cultivated for upland rice or cabbage, or when weed pressure is high. Tillage erosion results in a tillage step with low soil fertility and low infiltration capacity. Solutions to reduce tillage erosion intensity depend on the degree that tillage intensity can be reduced. This might happen by an improved weed management or by changing landuse to perrenial cropping. Other strategies are concentrating nutrients on the truncated hillslope sections and retaining soil on the field by vegetative buffers.     

控制坡地水力侵蚀危害的管理措施

根据坡面水力侵蚀由降雨击溅力和径流侵蚀力作用于坡面土壤,从而引起土壤颗粒的剪切破坏分离,被径流携带引起流失的作用机理,从植被覆盖、人工覆盖、消减径流量、减小径流流速、增强土壤抗分散、抗剪切能力等方面入手,采用适宜的生物、工程、耕作及化工产品综合措施,达到防止或减轻坡面侵蚀,保护土地生产力之目的。     

Modelling tillage erosion in the topographically complex landscapes of southwestern Ontario, Canada

A tillage erosion model was developed for southwestern Ontario based on the relationship between tillage translocation and slope gradient and slope curvature. Two studies of tillage translocation and tillage erosion were used to calibrate this model, one a comparison of upslope and downslope tillage translocation on shoulder slopes, the other an examination of tillage translocation throughout topographically complex landscapes. Two field sites were used for validation of the model. For both sites, past tillage practices were known and past soil erosion was determined using ¹³⁷Cs as an indicator of soil redistribution. The model accurately predicted the pattern of soil redistribution that had occurred within the two field sites. Severe soil loss was observed and predicted on convex landscape positions and soil accumulation was observed and predicted on concave landscape positions. The model accounted for almost all of the soil lost from the convex upper slope positions where tillage erosion was expected to be the dominant erosion process. There was considerable soil loss and accumulation elsewhere in the landscapes which could not be accounted for by the model and was presumed to be primarily the result of water erosion. It was concluded that tillage erosion must be incorporated into soil erosion modelling for the purposes of soil conservation.     

中国四川盆地地区侵蚀斜坡土壤酶活性研究

Determining how soil erosion affects enzyme activity may enhance our understanding of soil degradation on eroded agricultural landscapes. This study assessed the changes in enzyme activity with slope position and erosion type by selecting water and tillage erosion-dominated slopes and performing analyses using the ¹³⁷Cs technique. The ¹³⁷Cs data revealed that soil loss occurred in the upper section of the two eroded slope types, while soil accumulation occurred in the lower section. The invertase activity increased downslope and exhibited a pattern similar to the ¹³⁷Cs data. The spatial patterns of urease and alkaline phosphatase activities were similar to the ¹³⁷Cs inventories on the water and tillage erosion-dominated slopes, respectively. On both the eroded slope types, the invertase activity and soil organic carbon content were correlated, but no correlation was observed between the alkaline phosphatase activity and total phosphorus content. Nevertheless, the urease activity was correlated with the total nitrogen content only on the water erosion-dominated slopes. The enzyme activity-to-microbial biomass carbon ratios indicated high activities of invertase and urease but low activity of phosphatase on the water erosion-dominated slopes compared with the tillage erosion-dominated slopes. Both the invertase activity and the invertase activity-to-microbial biomass carbon ratio varied with the slope position. Changes in the urease activity-to-microbial biomass carbon ratio were significantly affected by the erosion type. These suggested that the dynamics of the invertase activity were linked to soil redistribution on the two eroded slope types, whereas the dynamics of the urease and alkaline phosphatase activities were associated with soil redistribution only on the water or tillage erosion-dominated slopes, respectively. The erosion type had an obvious effect on the activities of invertase, urease and alkaline phosphatase. Soil redistribution might influence the involvement of urease in the N cycle and alkaline phosphatase in the P cycle. Thus, enzyme activity-to-microbial biomass ratios may be used to better evaluate microbiological activity in eroded soils.     

近景摄影测量技术在坡耕地土壤侵蚀速率研究中的应用

以5°,10°,20°的紫色土坡耕地为研究对象,分别进行5,10,15次强度的模拟耕作试验,在此基础上采用60L/min的流量进行3轮放水冲刷试验,采用近景摄影测量技术监测试验前后紫色土坡耕地小区的地形变化,通过生成高精度DEM数据计算土壤流失体积,并采用插钎法测量土层深度变化,验证近景摄影测量技术测定地形变化的准确度,进而推算不同坡度条件下的紫色土坡耕地耕作侵蚀速率和水力侵蚀速率。结果表明:(1)采用近景摄影测量技术能够准确监测地形变化,其测算结果与插钎法的结果比较接近,且通过计算土壤流失体积推算土壤侵蚀速率的方法比较可靠,精度较高;(2)紫色土坡耕地在坡度为5°,10°,20°条件下平均耕作侵蚀速率分别为69.85,131.45,155.34t/(hm2·tillage pass),耕作侵蚀速率随坡度增加呈增加趋势,随着耕作次数增加则呈逐渐减小的趋势;(3)紫色土坡耕地在坡度为5°,10°,20°条件下平均水力侵蚀速率分别为1 892.52,2 961.76,4 405.93t/(hm2·h),水力侵蚀速率与坡度呈正相关关系,与此同时,随着耕作强度的增加,水力侵蚀也呈逐渐增大的趋势,表明耕作侵蚀对水力侵蚀有加速作用。该研究为紫色土坡耕地耕作侵蚀和水力侵蚀交互作用下的土壤侵蚀研究提供技术支撑和数据基础。     

降雨条件下耕作方式对地表糙度的溅蚀效应

地表糙度是影响坡耕地土壤侵蚀的主要因素之一,为了进一步明确耕作方式对地表糙度的侵蚀效应,该文通过室内人工模拟降雨的方法,就单雨强与组合雨强条件下耕作方式对溅蚀的作用以及地表糙度的变化进行了研究。结果表明,从对照坡面,经耙耱地、人工锄耕、人工掏挖到等高耕作方式的坡面,在雨强0.62 mm/min条件下,不同耕作方式坡面向上坡溅蚀量呈先增加再减小的变化,向下坡和总溅蚀量均呈先增加再减小最后增加的变化;除耙耱地外,其他耕作方式坡面的地表糙度呈减小的变化。在雨强1.53 mm/min条件下,不同耕作方式坡面向上坡、向下坡和总溅蚀量均呈先增加再减小最后增加的变化;地表糙度与对照坡面相反,均呈增加的变化。组合雨强条件下,随降雨强度的增加,耙耱地总溅蚀量与地表糙度呈一直增加的变化趋势;其他耕作方式下,随降雨强度的增加,坡面总溅蚀量呈先增加后减小的变化趋势,地表糙度却呈先减小后增大的变化。这为揭示地表糙度的侵蚀特征提供了一定的理论依据,同时也可服务于黄土高原坡耕地的水土流失治理。     

不同逆坡耕作强度对干热河谷区坡耕地水蚀的影响

为了研究不同逆坡耕作强度导致的土壤位移对坡面水蚀的影响,以金沙江干热河谷区坡面径流小区为研究对象,在径流小区5°,10°,15°坡面上,进行单宽流量为0.6 m^2/h的放水试验。在10°坡面的下坡位置设置0.05,0.10,0.20 m土层深度,分别代表连续耕作80,69,46年导致下坡位置土壤损失土层变薄情况。通过收集径流小区出口的产流量和产沙量,研究在不同坡度上的不同逆坡耕作强度导致的土壤位移对坡面产流率、产沙率、总流量和总产沙量的影响。结果表明:(1)在10°坡面,耕作年限越长,产流越快,不同耕作强度(年限)的产流率、总产流量、产沙率和总产沙量均表现46年<69年<80年的变化趋势,说明长期逆坡耕作导致的土壤位移加速了坡面水蚀的发生;(2)在耕作69年的坡面,坡度越大,产流越快。在测定坡度范围,产流率、总产流量、产沙率和总产沙量均表现出5°<10°<15°的变化趋势,即坡度的增加明显增大了坡面水蚀;(3)随耕作侵蚀强度的增大,坡面产流率与产沙率间的指数增长关系越显著,而坡度的增大弱化了水沙指数函数关系。研究成果可为揭示干热河谷区逆坡耕作强度和坡度对水蚀的作用机理提供参考。