Document Type : Research Paper
Authors
1 Associate Professor, Soil Conservation and Watershed Management Department, Kermanshah Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Iran.
2 Professor, Kermanshah Center for Agricultural and Natural Resources Research and Education, Agricultural Research, Education and Extension Organization (AREEO), Kermanshah, Iran
Abstract
The dieback phenomenon of oak (Quercus sp.) cause imbalance of land resources, increasing dust, soil erosion, flooding, climate change, and poverty of local communities. The objectives of this research was to determine the effects of the runoff harvesting system (crescent-shaped bunds) to combat forest dieback severity and improving soil quality in the Merek watershed, Kermanshah province, Iran. After constructing bunds, soil moisture was measured for three years (1400-1403). Furthermore, soil sampling carried out and subjected to soil analysis. Dead trees were counted in certain plots, and aboveground cover was also estimated. The results explored soil moisture in top soil (0-15 cm) bottom, downwards and between the bound as well as the control (without bund) were about 20, 17, 14 and 13%, respectively, which was significantly higher in the bund bottom. In deeper layer (15-30 cm) these respective value was about 20, 17, 14 and 13%, respectively, which was significantly higher bottom bund. Accordingly, soil organic matter in the third year in bunds and control treatments was 4.1 and 1.6%, respectively. In addition, bunds contributed to significant increase in very coarse soil aggregates, cation exchange capacity and soil nutrients. Finally, increasing soil organic matter and runoff accumulation in bunds reduced soil erodibility and adversely soil sustainability due to redaction soil erodibility index (0.19) compared to control treatments (0.32). According to the results of this research, the proper and precise construction of these bunds whiteout the use of heavy machinery is a simple, cheap, and effective method for harvesting rainwater causing soil moisture storage and subsequently enhancement of plant biological growth as well as improvement the key soil characteristics, including organic matter, increasing the proportion of coarse aggregates, bulk density, and soil nutrients, which leads to soil sustainable, carbon sequestration, curtailing flooding hazards on the hill-slope, and strengthening subsurface flow.
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