Roholah Zeynivand; Majid Ajorlo; Ali Ariapour
Abstract
This study aimed to investigate the effects of livestock grazing intensities (lenient, moderate, heavy and no-grazing) on herbaceous plant species composition and diversity (grasses and forbs) in understory of Quercus spp. and Pistacia spp. forest in Kebirkouh Mountain, Darehshahr city, Ilam Province, ...
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This study aimed to investigate the effects of livestock grazing intensities (lenient, moderate, heavy and no-grazing) on herbaceous plant species composition and diversity (grasses and forbs) in understory of Quercus spp. and Pistacia spp. forest in Kebirkouh Mountain, Darehshahr city, Ilam Province, Iran. Vegetation sampling was carried out with randomized-systematic method at flowering time of the dominant plant species in April 2017. Within each quadrat, number of species, name of plants, density, life form and palatability class were recorded for herbaceous plants. Species diversity with the Simpson’s and Shannon-Weiner indices, species richness with Margalef and Menhinick indexes, and evenness with Peet and Sheldon indices were calculated in Ecological Methodology software version 6.1.4. The highest value of Simpson index for grasses and forbs was 0.972 (moderate grazing) and 96.95 (exclosure). Also, the highest value of Shannon index for grasses and forbs was 4.51 (heavy grazing) and 4.56 (heavy grazing), respectively. The highest richness of grasses and forbs was observed in grazed area with moderate intensity and no-grazing area, respectively. In the area without grazing, the richness of forbs was 4.4 and 2.75 according to Margalef and Menhinick indexes. The values of the Margalef and Menhinick richness indexes for grasses in grazed area with a moderate intensity were18 and 15 percent higher than the grazed area with heavy intensity. Peet and Sheldon evenness indexes were the highest for grasses and forbs in heavily grazed area and the lowest for grasses in the moderate grazing intensity and for forbs in the exclosure.
Majid Ajorlo; Mahboubeh Ebrahimian; Ramdzani Abdullah
Abstract
Root morphological and distribution responses of signal grass (Brachiaria decumbens) to long-term cattle grazing were examined in a tropical pasture in Malaysia. The treatments were no grazing by cattle and grazing at a moderate stocking density (2.7 animal unit/ha) under rotational grazing for 33 years. ...
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Root morphological and distribution responses of signal grass (Brachiaria decumbens) to long-term cattle grazing were examined in a tropical pasture in Malaysia. The treatments were no grazing by cattle and grazing at a moderate stocking density (2.7 animal unit/ha) under rotational grazing for 33 years. The method consists of taking soil core using a soil corer to a depth of 30 cm and extracting roots from cores by hand-washing and subsequent measuring of root morphological characteristics including length, surface area, average diameter and volume using WinRhizo Root Scanner. Root length density, mass density, surface area density, and volume density were calculated as indicators of root distribution pattern in the soil volume. Data were analyzed using repeated measure analysis of variance and independent t-test. Root diameter, length and length density were affected neither by grazing treatment nor the interaction between them (P > 0.05). Root diameters in the middle (10–20 cm) and lower (20–30 cm) soil layers of grazed site were 50% and 72% greater than that in the ungrazed site. Root volume, surface area and their densities were not affected (P > 0.05) by grazing and the interaction between grazing and soil depth. Mean root mass and mass density were affected (P < 0.05) by moderate grazing and soil depth, and the interaction between them. Mean root mass in all soil depths in grazed site was greater than that in the ungrazed site. Long-term rotational moderate grazing has no negative impact on root variables of signal grass in tropical pasture.
