The Effect of pear tree vegetation of chamhesar، Lorestan on Some Soil Chemical Properties

Some forest management, in addition to direct impact on soil, will also affect indirectly soil physical and chemical properties by changing or degrading vegetation cover. Accordingly, forest reserves are most common protection systems in the Iran forest ecosystems management that can affect physio-chemical properties of soil directly or indirectly. Since there are not enough studies to quantity the effects of this type of protection on soil properties in Iran, therefore, this study was done by following aim: to assessment the effect of short-term protection management on some chemical properties of the soil in Chamhesar Pear forest reserve in Delfan. Thus assessing the impacts of this type of management on the soil can lead managers to continue the process.
In addition, sampling of soil in the core and buffer zones of the studied area, a region with similar physiographic characteristics was selected outside the reserve (as control). Soil samples were collected on three transects with 250 m length and north-east to south-west direction with a height difference of 40 meters towards the core and buffer zones. Each transect consist of 3 zones: core, buffer and transition zones. Soil samples were collected at intervals of 20 meters on each transect under crown of the nearest Pears tree at depth of 10 cm. Overall in the three transects, 36 soil samples were taken. Then the normalization of the data was determined by Kolmogorov-Smirnov test, the comparison of the means and multiple comparison of the means was done respectively using one-way ANOVA and Duncan test.
The results showed that there was a significant difference between the amounts of organic carbon, total nitrogen, phosphorus, potassium, electrical conductivity, acidity and magnesium of soil in three zones. The highest amount of organic carbon (9.57%), nitrogen (0.25%), phosphorus (4.32 mg / kg), potassium (57.33 mg / kg) and electrical conductivity (198.70 µs/ m) was measured in the soil of core zone and the highest levels of acidity and magnesium of soil was 7.62 and 8.56 mg/kg respectively, in the transition zone. In the other words, the amount of carbon, nitrogen, phosphorus, potassium and electrical conductivity of soil has increased and level of acidity and magnesium of soil has decreased from the transition zone to core zone.
The results of this study showed that protection management had positive effect on the chemical properties of soil. In fact, protection has been caused to preventing grazing, increasing vegetation cover and decreasing rate of destruction, as a result a significant effect on some chemical properties of soil.