It is estimated in the future that forest vegetation cover in the forest zone could reach 30%,in the forest-grass zone,forest vegetation cover could be less than 20% and shrub and grass cover reaches above 50%, in the grass zone, vegetation cover could be less than 50%.
The potential grass and shrub region lies in the down of the watershed, which accounts for 39.94% of total area, among these there are 150 250 hm 2 degraded grass land. 79 500 hm 2 natural shrub and grass changed to farm land.
For any forest layer including tree, shrub and grass, the relative biomass density in broad leaf forest was highest, followed by that in mixed and conifer forest.
It is obvious that sparse wood grass, mixed with trees, shrub and grass in life areca is better than factory sparse lawn and contrast ground in increasing air humidity, lowering the wind velocity and protecting the water of soil.
The result showed that the soil volume weight (0～40 cm) of mango fruit garden was 1 34～1 45 g/cm 3, 0 05～0 12 g/cm 3 lower than that of shrub-grass vegetation(1 46～1 50 g/cm 3) repecstively.
Based on the observation to roots profile and analysis on soil samples about Robinia pesudoacacia and caragana korshinskii and herb, the results show that:①Hair roots distribution of arbor and shrub and herb is different from that of original geomorphy, below surface about 10cm, hair roots distribution follows exponential function, ruturn equations being successively: y刺槐=11.961x-0.8213(R2=0.8141);
Thinning stands with the thinning intensity of about 20% and 30% had no significant effects on species diversity, biomass of shrub and herb, and physical properties of soil.
The results showed,that being different from that of original geomorphy, below surface about 10 cm,hair roots of arbor and shrub and herb(Φ≤1 mm) distribution followed exponential function;
Dwarf shrub and grass heaths that were common on the mainland did not occur on grazer-free Bear Island and Jan Mayen, and were confined to the lowest altitudes on Spitsbergen.
The location of individual roots intersecting a sliced soil core surface was digitized and the identity of shrub and grass roots was established by a chemical technique.
Total average rooting density in patches varied among these different treatment combinations by only a factor of 2, but the proportion of shrub and grass roots in the patches varied sixfold.
Through the investigations of Yang Si Chuan, we have found out that there are 3 major problems. 1. Fuel shortage. In the years of bumper harvest the fuel can be used only for 8 months, while in the drought years somewhat for 6 months. During the rest months, roots of plants are dug out to be used·as fuel. 2.Manure shortage is another problem. 100kg of artificial fertilizer per mu is usually applied. So the output is as low as 50 kg per mu, and during bad years it is only 25kg per mu. 3.Forage grass shortage...
On the basis of on-the-spot investigation,the characteristics of natural environment and the types of plant resources in Huang Ling testing region are expounded in this thessis, hence the main methods to improve the ecologic environment, raise the per unit yield and output value, and increase the peasauts' income in sand area are put forward. Biological measures which would be taken are developing forestry and cash crops with the combinations of production, supply, and marketing. Plannting trees, bushes and...
It is known that the soil loss area of Jiangsu Province is about 4,395.5km~2 from the interpretation by remote sensing and the measurement byphotoelectric scanner, in which the area of slight to light erosion is3,674.4km~2, in moderate and strong erosion is 578.6km~2 and 142.5km~2 res-pectively, being amounted to 83.6%, 13.2% and 3.2% of the total respec-tively.From the point of risk extent, the area in no risk is 71.5%, in somerisk 14%and much risk 14.5% of the total. The control measures are toimprove the...
灌草
shrub and grass
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