The forests of North Mongolia are largely dominated either by larch (Larix sibirica Ledeb.) or birch (Betula platyphylla Sukaczev). The increasing demand for timber and firewood is currently met by removal of wood from these forest stands. Therefore, silvicultural approaches that account for both utilization and protection are needed. Thinning trials were established in the research area Altansumber, in the mountain forest steppe west of the town of Darkhan. We analyzed the response of non-spatial and spatial structure and growth of birch and larch stands on thinning. Before thinning, spatial tree distribution was largely clumped. Thinning promoted regular tree distribution. Ingrowth of new stems after thinning tended to redirect stand structure towards clumping. Both relative and absolute tree growth and competition were evaluated before, directly after, and three years after the thinning. Competition played a significant role in tree growth before thinning. A reduction in competition after thinning triggered significantly increased growth of both birch and larch. The observed positive growth response was valid in absolute and relative terms. A methodically based forest management strategy, including thinning operations and selective cuttings, could be established, even under the harsh Mongolian conditions. Our findings could initiate the development of broader forest management guidelines for the light-taiga dominated stands.

One of first soil investigation of Mongolia made by Russion famous scientist B. Polynov in 1925, in the Uvur Jargalant area of Central aimag. In 2018 we made soil investigation on the same area with aim of soil organic matter (SOM) change issue. Average drop of steppe SOM after 90 years is following: in the 5 cm soil depth -51.5 %, in 10 cm soil depth is -33.2 % and 30 cm soil depth is about -11.1 %. In the below 30 cm soil of depth no change of SOM. By landscape positions SOM change differed. Mountain top area and valley bottom area SOM is more declining comparing to the footslope area soils. For 0-30 cm top soil layer weighed average change of SOM within 90 year is -30.9 % and SOC stock decline is 16.5% or 15.4 t/hectare. Impact of livestock pressure and climate warming on soil is significant, need to renew pasture management policy.

The active pool of SOC forms a relatively small portion of total SOC but it plays important roles in maintaining and monitoring soil quality. Soil samples were collected from three depths with two replications in June, 2018. The collected soil samples were subjected to analyses for physico-chemical properties such as particle size analyse, pH, EC, soil organic carbon, available phosphorus and potassium and permanganate oxidizable organic carbon. We measured POXC by spectrophotometer using 0.02 M KMnO4 at 550 nm light. POXC was from 0.7 to 7.7 % of SOC in our study. POXC is a good indicator of soil organic fraction in environmental monitoring programmes for arid environments. POXC determination is relatively simple and promising method that could be adopted by soil test laboratories for use in routine soil samples. Permanganate oxidizable C (POXC; i.e., active C) is a relatively new method that can quantify labile soil C rapidly and inexpensively.

One of the major sources of soil pollution in Ulaanbaatar is the auto repair and maintenance centers of major auto sales and service centers such as Da Khuree, Diesel Khuree, Mungun khuleg and Buyan Khurah, Bayanzurkh districts. 30 samples were taken from 29 sites and 57% of total samples (n=30) were organic pollutants, 30% were polluted with ammonia and 10% had sulfate pollutants. The soil of the "Da Khuree" field has a high pollution of lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) in the soil. The percentage of soil pollution exceeding the standard (MNS 5850) is Lead (Pb) 30%, Cadmium (Cd) 6.7%, Chromium (Cr) 6.7%, Copper (Cu) 33.3%, Zinc (Zn) 30.0% are polluted.

One of first soil investigation of Mongolia made by Russion famous scientist B. Polynov in 1925, in the Uvur Jargalant area of Central aimag. In 2018 we made soil investigation on the same area with aim of soil organic matter (SOM) change issue. Average drop of steppe SOM after 90 years is following: in the 5 cm soil depth -51.5 %, in 10 cm soil depth is -33.2 % and 30 cm soil depth is about -11.1 %. In the below 30 cm soil of depth no change of SOM. By landscape positions SOM change differed. Mountain top area and valley bottom area SOM is more declining comparing to the footslope area soils. For 0-30 cm top soil layer weighed average change of SOM within 90 year is -30.9 % and SOC stock decline is 16.5% or 15.4 t/hectare. Impact of livestock pressure and climate warming on soil is significant, need to renew pasture management policy.

One of first soil investigation of Mongolia made by Russion famous scientist B. Polynov in 1925, in the Uvur Jargalant area of Central aimag. In 2018 we made soil investigation on the same area with aim of soil organic matter (SOM) change issue. Average drop of steppe SOM after 90 years is following: in the 5 cm soil depth -51.5 %, in 10 cm soil depth is -33.2 % and 30 cm soil depth is about -11.1 %. In the below 30 cm soil of depth no change of SOM. By landscape positions SOM change differed. Mountain top area and valley bottom area SOM is more declining comparing to the footslope area soils. For 0-30 cm top soil layer weighed average change of SOM within 90 year is -30.9 % and SOC stock decline is 16.5% or 15.4 t/hectare. Impact of livestock pressure and climate warming on soil is significant, need to renew pasture management policy.

The active pool of SOC forms a relatively small portion of total SOC but it plays important roles in maintaining and monitoring soil quality. Soil samples were collected from three depths with two replications in June, 2018. The collected soil samples were subjected to analyses for physico-chemical properties such as particle size analyse, pH, EC, soil organic carbon, available phosphorus and potassium and permanganate oxidizable organic carbon. We measured POXC by spectrophotometer using 0.02 M KMnO4 at 550 nm light. POXC was from 0.7 to 7.7 % of SOC in our study. POXC is a good indicator of soil organic fraction in environmental monitoring programmes for arid environments. POXC determination is relatively simple and promising method that could be adopted by soil test laboratories for use in routine soil samples. Permanganate oxidizable C (POXC; i.e., active C) is a relatively new method that can quantify labile soil C rapidly and inexpensively.

The active pool of SOC forms a relatively small portion of total SOC but it plays important roles in maintaining and monitoring soil quality. Soil samples were collected from three depths with two replications in June, 2018. The collected soil samples were subjected to analyses for physico-chemical properties such as particle size analyse, pH, EC, soil organic carbon, available phosphorus and potassium and permanganate oxidizable organic carbon. We measured POXC by spectrophotometer using 0.02 M KMnO4 at 550 nm light. POXC was from 0.7 to 7.7 % of SOC in our study. POXC is a good indicator of soil organic fraction in environmental monitoring programmes for arid environments. POXC determination is relatively simple and promising method that could be adopted by soil test laboratories for use in routine soil samples. Permanganate oxidizable C (POXC; i.e., active C) is a relatively new method that can quantify labile soil C rapidly and inexpensively.

One of the major sources of soil pollution in Ulaanbaatar is the auto repair and maintenance centers of major auto sales and service centers such as Da Khuree, Diesel Khuree, Mungun khuleg and Buyan Khurah, Bayanzurkh districts. 30 samples were taken from 29 sites and 57% of total samples (n=30) were organic pollutants, 30% were polluted with ammonia and 10% had sulfate pollutants. The soil of the "Da Khuree" field has a high pollution of lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) in the soil. The percentage of soil pollution exceeding the standard (MNS 5850) is Lead (Pb) 30%, Cadmium (Cd) 6.7%, Chromium (Cr) 6.7%, Copper (Cu) 33.3%, Zinc (Zn) 30.0% are polluted.

One of the major sources of soil pollution in Ulaanbaatar is the auto repair and maintenance centers of major auto sales and service centers such as Da Khuree, Diesel Khuree, Mungun khuleg and Buyan Khurah, Bayanzurkh districts. 30 samples were taken from 29 sites and 57% of total samples (n=30) were organic pollutants, 30% were polluted with ammonia and 10% had sulfate pollutants. The soil of the "Da Khuree" field has a high pollution of lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) in the soil. The percentage of soil pollution exceeding the standard (MNS 5850) is Lead (Pb) 30%, Cadmium (Cd) 6.7%, Chromium (Cr) 6.7%, Copper (Cu) 33.3%, Zinc (Zn) 30.0% are polluted.

We focused on soil heavy metal and biological study of Bulgan aimag. Pit latrine and other biological pollution sources due to soil polluted. One of the main target is define to soil pollution transport to deep. We selected 4 point in this aimag center according to variety of relief. Soil polluted by biological aspects by pit latrine in ger districts in Bulgan aimag. E coli bacteria observed about 78% in amount samples by according to research material. E.coli, Proteus and salmonella bacteria infiltrate and to go deep in soil by water and others. That bacteria’s found in 3.5-4 meter in site 1, 2 and 3. Soil is best cleaning mechanism and complex in the world.