矸石山复垦造林技术的研究

经过1985—1989年时间,将对抚顺、辽原、鹤岗等矿区进引了考察研究,采用矸石风化混合物的物理性质、化学性质的分析,参考植被演替过程及植被种类的划分,对鹤岗矿务局岭北矿排矸区进引复垦造林树种筛选试验和复垦造林技术研究,并取得明显效果。研究结果,选择樟子松和落叶松作为该地区矸石山复垦造林的主要树种。为治理环境、恢复植被、造福于人类提供科学依据。     

Mineral nutrition, soil factors and growth rates of Gmelina arborea plantations in the humid lowlands of northern Costa Rica

The purpose of this study was to determine the factors which are responsible for clearly visible growth irregularities in Gmelina arborea stands by relating growth rates to soil and site properties. All Gmelina plantations under study, established on degraded pasture soils in the Atlantic lowlands of Costa Rica, showed the same growth pattern: very poor growth and chlorotic foliage of trees in mid-slope positions, and fast growth and healthy leaves of trees on hilltops and hillbases. The variation in site and soil properties and tree growth rates was analysed, investigating 24 plots in eight different plantations. Leaf samples were taken from 120 trees (five trees per site). Foliar analysis revealed that the tree growth is highly dependent on the supply of N, P, K and S, indicating that poorly growing trees suffer from a multiple nutrient disorder. To identify the most restricting soil factor, simple correlations between growth rates and soil chemical and physical properties were applied to the entire data set. The best correlation was obtained with exchangeable soil K (r=0.78, P<0.001). Subdivision of the data set into plots on brown soils (eight) and plots on red soils (16) and subsequent correlation analysis resulted in much stronger relationships. Growth depressions in mid-slope positions had other causes on brown soils than on red soils. On the acid brown soils the combination of the variables Al saturation and bulk density could explain 82% of the variation of tree growth. Al saturation of up to 80% in brown soils inhibits nutrient uptake, particularly of N and P. The red soils dominate on Ca---Mg-enriched, alluvial terraces and were among the first soils to be cultivated in the region. During the agricultural use and at the establishment of the tree plantations, they received dolomitic lime to reduce Al toxicity. Here, very low K/Mg ratios (less than 0.03) may induce K deficiency. Therefore, the best multiple regression model for tree growth rates on red soils is obtained with K/Mg ratio and thickness of the humic A-layer (r²=0.75, P<0.001). Inclusion of the variable bulk density resulted in a clear improvement of the model, explaining 91% of the growth variability.     

Effects of mineral and organic fertilizers on the microfauna in a high-altitude reafforestation trial

Summary Protozoa (testate amoebae, ciliates), small metazoa (rotifers, nematodes), and soil enzymes (catalase, cellulase) were investigated in a reafforested fertilized site at the alpine timberline. Side-dressings of mineral and organic fertilizers were applied alone (90 g NPK; 90, 180, 300, and 450 g dried bacterial biomass per spruce seedling) and in combination with magnesite (90 g NPK+300 g Mg; 90, 180, and 300 g bacterial biomass + 300 g Mg each; 30 g dried fungal biomass + 270 g Mg). One-third of each quantity was applied in 1986, and two-thirds in 1988. None of the treatments caused a significant decrease in the biological parameters investigated in comparison with untreated controls. The soil life was more or less stimulated depending on the amount of organic material contained in the fertilizers and the quantity; 180–270 g organic material per seedling proved to be the most effective. Dried bacterial biomass increased the pH by about 0.5 units, catalase activity by about 70%, and the number of ciliates and nematodes by 150–400%. The ciliate biomass and the number of ciliate species were likewise increased. The organomineral fertilizers increased pH by up to two units and also stimulated the soil life, but where the organic content was less than 180 g per seedling, efficiency decreased markedly. The least biological activity was observed in the control soil and in soil fertilized with NPK. Testaceans, rotifers, and cellulolytic activities were only slightly (insignificantly) affected by the treatments. A pooled evaluation of the data (organic versus organomineral versus mineral treatments) and community analyses showed that the organic fertilizer caused a more pronounced increase in the soil life and greater changes in community structure than the mineral combinations. Two years after application of the fertilizers, the differences between the treatments and the unfertilized controls had diminished.     

桂西北退耕还林模式下小流域径流特征研究

通过对桂西北石山区退耕还林样地进行地表径流量调查研究,发现不同类型地表径流的变化规律,为该地区退耕还林工作提供依据,从而选择更有效的退耕还林类型,加快该地区生态环境的恢复。研究结果表明：①地表径流跟土壤理化性质以及气温有关,月地表径流量与当月的日平均降雨量有关。②3个样地年平均地表径流量为：喜树人工林（2.52 mm）〉玉米地（2.17 mm）〉喜树＋吊丝竹人工林（0.84 mm）,说明喜树＋吊丝竹样地的地表径流量较小,其保持水分效果比喜树和玉米样地好,是较好的退耕还林模式。③不同植被类型地表径流量与降雨量的关系为：地表径流量与降雨量存在一定的线性关系,总体的趋势是地表径流量随着降雨量的增加而增大,两者呈正相关,但是地表径流量与降雨量不是正比关系,两者相关性不显著。     

Time lags in provision of habitat resources through revegetation

Broadscale land use changes are occurring rapidly in rural landscapes worldwide, within which revegetation with native plant species to increase the area of suitable habitat is a key activity. Current models for planning revegetation are based solely on the spatial arrangement of new and remnant vegetation. Making wise decisions about revegetation requires projective models of ecological responses to revegetation, but there are few appropriate data. Substantial time lags are expected in the availability of many habitat resources because different resources are realised at different stages of vegetation maturation. Here we present results of surveys of 72 revegetation sites established over a range from 5 to more than 130 yr from the slopes and plains of central Victoria, Australia. We surveyed vegetation provision of habitat resources essential for many birds and arboreal and scansorial mammals (e.g. canopy, large boughs, tree hollows and fallen timber). Predictive models were developed for habitat resource provision as functions of time since planting, planting density and other covariates. Different habitat resources developed at different rates. While dense canopy and various forms of bark resources developed in about 10 yr, large boughs, tree hollows and fallen timber loads required at least 100 yr to develop. The development of these key habitat resources was delayed in revegetated sites with high stem densities. Habitat resources that are essential for many birds and arboreal and scansorial mammals have long time lags that models for planning offsets or landscape reconstruction should account for. Management has substantial effects: planting at high densities greatly reduces tree girth growth rates and delays the occurrence of large boughs, tree hollows and fallen timber by decades.     

贵州省退耕还林工程存在的问题与对策

通过调查研究，分析了我省退耕还林工程中在的问题，提出了解决问题的对策。     

The degradation of the algerian environment through economic and social ‘development’ in the 1980s

Concern for the better management of environmental resources grew during the 1980s. While this concern encompassed the misuse of the Third World's resources, those nations' governments and their peoples showed less awareness of the environmental damage being done in their quest for development. Environmental degradation has reached serious proportions in Algeria where oil wealth has masked failings of agricultural production and, together with industrialization, has provided a ‘veneer’ of economic development. The vulnerability of Algeria's natural environment and the fragility of its ecosystems have been stressed by Cǒte (1983). Once cleared, Algeria's woodlands and forests are slow to re-establish and surface deposits are easily erodable. Soils were largely formed under past climatic conditions, and so cannot be restored naturally by present pedogenetic processes. Such an environment is difficult and delicate to exploit to any high degree of agricultural intensification and is under increasing demographic pressure. Culturally and organizationally the agricultural system is far from ideal if agriculture is to be sustained. Often in Algeria the highest rainfall falls on the steeper slopes while the gentler slopes receive insufficient for agriculture. Only 500 000 hectares out of Northern Algeria's 38–40 million hectares receive more than 600 mm of rainfall and have slopes of less than three per cent (Cǒte, 1983). As much as 20 million hectares of Northern Algeria were identified by Dregne (1983) as … ‘vulnerable to desertification’ with large areas falling into his ‘severe’ risk category. This study seeks to demonstrate the dimensions of environmental degradation through observations and the monitoring (during the 1980s) of Algeria's media: largely newspaper and television reports. Particular emphasis is placed on the growing environmental ‘crisis’ since 1988. It should be stressed that the Algerian Government uses a controlled media to disseminate official information. Misuse and overuse of environmental resources have combined with inadequate government economic policies and a neglect of ecological issues to cause the ‘crisis’.     

Effects of deforestation on microbial diversity in a Siberian larch(Larix sibirica) stand in Mongolia

For evaluating microbial community changes in a Siberian larch stand disturbed by forest fire or clearcutting,357 clones were randomly selected and sequenced using a culture-independent approach and 16S rRNA sequencing to characterize the bacterial composition and diversity from the different disturbed Siberian larch stands.Interestingly,the burned larch stand had an increase in the relative amounts of b-proteobacteria and Firmicutes and a decrease in Acidobacteria,while Gemmatimonadetes increased Verrucomicrobia decreased in the harvested larch stand.Microbial diversity and richness were higher in the undisturbed larch stand than the disturbed(burned or clear-cut)larch stands,and the influence of clear-cutting was more negative than that of the forest fire.This study indicates that evaluating the microbial diversity of undisturbed,burned,and clear-cutting Siberian larch stands provides information about the impact of forest disturbances on soil microbial communities,which may be helpful for understanding and evaluating soil health and devising reafforestation strategies for larch.     

贵州省建造石头梯田对限制水土流失的效益和风险分析

在贵州全境建造石头梯田来减少水土流失的现象十分普遍。但此项技术本身却有其固有的风险性。石头梯田通常比土质的梯田高,填在石头挡墙中的土壤的量更大,更易导致梯田的垮塌,也会减少梯田上部的土壤,降低土壤的养分和水分含量。石头的挡墙会威胁土地的长期生产力,因为一旦石头挡墙垮塌,所有的碎石就会堆积在下部的梯田中,使耕作十分困难。这种垮塌现象会通过增加地表径流而形成冲沟,使向下的沉积物运输增加。尤其是梯田之间的人工排水道使这种风险加剧。因为这种排水道使降水很难渗人土壤中,使土壤的保水和蓄水能力下降,从而造成作物的受旱。水流通过排水道输送的速度加快,很容易造成水流的汇集,增加洪水泛滥的可能性。由于建造了排水道,即使一般的暴雨,也会因为输送速度的加快而导致洪峰升高而成灾。因此,对水土流失的工程治理方式不应该取代、而应该与好的土地管理策略相结合。尽管土地利用方式有所改变,但通过采用新技术和坚持可持续发展的原则,在此类的土地上仍可获得最高的产量。图7表1参14。