森林与可持续发展

可持续发展是人类社会全方位的发展、进步、优化选择,而森林是可持续发展的保障。当今,水土流失,耕地退化,土地沙化,水资源不足等诱发的生态环境恶化,是制约我国实施可持续发展战略的障碍因素,以及“温室效应”,无不与森林有关,最好,最有效的方法是造林种草。当今全世界人民齐声大合唱的最强音,是保护环境,保护森林。森林,是民族繁荣的标志。     

Growth of four tree species managed as hedgerows in response to liming on an acid soil in West Sumatra,Indonesia

A hedgerow intercropping study was conducted for 7 years in West Sumatra, Indonesia on an acid and highly Al-saturated soil to determine growth and yield responses of tree hedgerows and upland rice and cowpea intercrops. Three tree species,Paraserianthes falcataria, Calliandra calothyrsus, andGliricidia sepium and a no-tree control were planted at three lime rates with low annual fertilizer inputs of 20 kg P and 50 kg K ha^–1.Paraserianthes andCalliandra grew vigorously, whileGliricidia grew poorly and was replaced after four years withFlemingia macrophylla. After four years,Paraserianthes yields declined due to tree mortality, probably due to intensive pruning.Calliandra andFlemingia were well adapted to intensive pruning (4 to 6 times per year). Gliricidia growth was especially limited by low soil Ca availability and high soil acid saturation.Calliandra andFlemingia yields increased with liming only in the last several years of the study whileParaserianthes did not respond to lime. The species can be tentatively ranked in response to lime as:Gliricidia > Calliandra > Flemingia > Paraserianthes.     

秦岭南坡中山地带华北落叶松人工林对土壤的影响

秦岭南坡中山地带华北落叶松人工林对土壤的影响雷瑞德，党坤良，张硕新，谭芳林（西北林学院森林资源保护系杨陵７１２１００）关键词华北落叶松，土壤养分状况，阳离子交换量，酶活华北落叶松（Ｌａｒｉｘｐｒｉｎｃｉｐｉｓ－ｒｕｐｐｒｅｃｈｃｉｉＭａｒｙｒ．）天然...     

Seasonal changes of understorey herbage yield in relation to light intensity and soil moisture content in a Pinus pinaster plantation

The relationship of understorey herbage yield with light intensity and soil moisture content was investigated in a 20-year-old Pinus pinaster plantation in Kilkis of Macedonia, northern Greece, in three seasons (fall, winter and spring). The plantation was thinned at three density levels, high, medium and low (2500, 1750 and 1000 trees/ha respectively) and it was seeded with Dactylis glomerata. In addition, two fertilization levels (0 and 110 N+150 P₂O₅ kg/ha) and grazing intensity levels (0 and 0.8 sheep/ha/yr) were applied in a split-split plot experimental design. It was found that herbage yield was highest in the ungrazed and fertilized low tree density stands in all seasons. In the medium tree density stand, although light was lacking, fertilized plots produced higher herbage yield as compared to unfertilized low tree density stands while fertilization is of no use in close stands if herbage production is the goal. Animals seemed to prefer fertilized and medium density stands. Third degree polynomial equations were the best to explain herbage variation through the seasons both in fertilized and unfertilized plots.     

Microclimate and soil moisture effects of three intercrops on the rows of a newly-planted intercropped plantation

Trees are grown in intercropping systems for a variety of purposes including wood products, fuelwood, fruit, forage or conservation purposes. No matter what end use, different tree/crop combinations interact differently resulting in differential growth rates of the trees during establishment. Preliminary work has shown that seedling growth and survival of trees are related to their intercrop and the results of this study help to explain these findings. Soil water potential, soil and air temperature, relative humidity, windspeed, and light (photosynthetic photon flux density — PPFD) were measured throughout the growing season in the clean-weeded treerows within crops of corn, soybeans and winter wheat. Crop height and biomass were also measured. This study was conducted during the 1992 growing season which was unusually cool and wet from mid June into the winter. The growth of winter wheat, measured by crop height and above-ground biomass, was earlier in the season than that of soybeans and corn, and this pattern affected the environmental conditions in the tree rows. Soil water potential was affected with associated effects on soil temperature (in combination with other factors). Crop height drastically reduced windspeed in the corn treatment from July through winter, also affecting PPFD and soil temperature later in the year. Although many microclimate differences were relatively small, data from subsequent years as well as associated soil moisture studies and additional years will help to further elucidate these relationships.     

Non-additive Effects of Leaf Litter Mixtures from Robinia pseudoacacia and Ten Tree Species on Soil Properties

ABSTRACT

Litter decomposition plays a critical role in both nutrient cycling and the interspecific relationships between tree species. In this study, leaf litter from Robinia pseudoacacia was mixed with litter from 10 other species, this mixture was then ground and incubated in soil. The soil indexes (i.e., quantity of microbes, activities of enzymes, and chemical properties) were analyzed to study the effects of litter decomposition on soil properties and the interaction between the litters. If mixed separately with Larix principis-rupprechtii or Betula platyphylla, R. pseudoacacia litter exerted synergistic effects on the activities of most enzymes. The mixed litters of R. pseudoacacia and Pinus sylvestris var. mongolica or Ulmus pumila exerted synergistic effects on the soil available P. With regard to the soil properties as a whole, the mixed litters of R. pseudoacacia and B. platyphylla, Pinus tabulaeformis, P. sylvestris var. mongolica, or L. principis-rupprechtii exerted synergistic effects on soil during their decomposition. However, the mixed litters of R. pseudoacacia and Populus simonii, Quercus liaotungensis, U. pumila, or Caragana microphylla did not. This indicated that R. pseudoacacia mixed with the litter of other needle-leaf tree species benefits the development and regeneration of soil and thus can be used for sustainable forest management.     

秦岭南坡不同海拔土壤肥力的空间分异规律

对秦岭南坡土壤肥力状况、空间分异规律及其与海拔的关系进行研究.结果表明,秦岭南坡土壤肥力指标在整个土壤剖面空间分异范围分别为:土壤pH值5.97～6.89,有机质含量6.6～50.1 g·kg-1,土壤全N含量0.5～3.8 g·kg-1,碱解N含量33.6～257.3 mg·kg-1,速效P含量0.81～5.8 mg·kg-1,速效K含量38.9～262.4 mg·kg-1,粘粒含量11.3%～18.1%,阳离子代换量68.5～310.2 mmol·kg-1;其空间分异程度以速效P、有机质和土壤全N含量较大,土壤粘粒含量和土壤pH值较小;随着土层的加深,土壤pH值、有机质、速效P、土壤粘粒含量和阳离子代换量空间分异程度减小,而土壤全N、碱解N和速效K含量空间分异程度增大.土壤速效K、速效P含量和阳离子代换量水平空间分异程度受海拔的影响较大,而土壤pH值和粘粒含量水平空间分异程度受海拔影响较小.随着海拔的升高,土壤pH值降低,有机质和速效P、K含量增大,土壤肥力空间分异程度减小,这可能与随着海拔升高人为干扰强度降低及林分类型趋向单一有关.     

混农间作对兴安落叶松人工林土壤生态条件的影响

以落叶松人工纯林及落叶松与大豆混农间作人工林下土壤为研究对象,对不同林分下土壤物理性质和化学性质进行测定及比较分析,结果表明:混农林的土壤容重低于纯林,土壤总孔隙度和含水量大于纯林。另外,落叶松与大豆间作使土壤有机质含量增加,全N、速效N、P、K的含量增加,其中间作林土壤中N素含量增加尤为明显。     

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]     

新西兰辐射松根朽病与温度、湿度关系的数量模型*

新西兰辐射松根朽病与温度、湿度关系的数量模型束庆龙，宋淑梅，赵卫中，Ｎ．Ｍ．Ｓｅｌｆ关键词辐射松根朽病，温度，降雨量，土壤湿度，数量模型早在１９３０年，新西兰就有关于４年生辐射松ＰｉｎｕｓｒａｄｉａｔａＤ．Ｄｏｎ幼树受根朽病危害致死的报道［１］。６０...