Farhad Ghasemi Aghbash, Geshin Allah Veisi, Vahid Hosseini,
Volume 3, Issue 1 (9-2016)
Abstract
Litter decomposition is the most important way of nutrient entering to soil and soil nutrient availability is highly related to dynamics of nutrients and litter decomposition in the forest ecosystems. This study aimed to evaluate the dynamics of nutrients and litter decomposition in the northern Zagros forests using litterbag technique for 180 days in the Khul Hoare forests located in Baneh city. The litter bags were collected at intervals of 30, 60, 120 and 180 days and the rate of leaf litter decomposition and chemical compounds such as nitrogen, carbon, phosphorus, potassium and calcium were measured. The results showed there was no significant correlation between the rate of decomposition and the initial composition of nutrients and also C: N and C: P ratios. Due to the qualification of leaf litter based on the amount of nitrogen in this study, the average amount of nitrogen in Quercus libani was 1.37%. So Lebanon oak can be classified in the average group and it can be considered as a soil improver species. In the studied litter, phosphorus and nitrogen had a similar performance and their concentration increased over time (7.27 and 30.38 mg/g respectively). While concentration of elements such as calcium, potassium and magnesium was decreased. The nutrient concentration of Quercus libani leaf litter was Ca>N>P>K> Mg.
Leila Ranjbar, Payam Fayyaz, Ebrahim Adhami, Hamidreza Owliaie, Roghayeh Zolfaghari,
Volume 4, Issue 1 (12-2024)
Abstract
Background and objectives. By accelerating of the intensity and duration of the drought periods in the Zagros forests, the revival of native tree species, including the brant’s oak (Persian oak), is diminished. Despite the knowledge of the importance of phosphorus in increasing drought resistance in different species, there is little information about the role of this element in brant’s oak seedlings in facing drought.
Materials and methods: For this purpose, the main and interactive effects of two factors of soil phosphorus (at five levels of zero, 25, 50, 75 and 100 mg/kg) and soil moisture regime (at three levels of 60, 30 and 10 percent of field capacity) on performance traits of one-year-old brant’s oak seedlings, with six replications, have been examined. The studied traits include morphological traits (root and stem length, number and area of leaves, fresh weight of roots, stems and leaves), physiological traits (relative water content and electrolyte leakage rate in different organs of leaves, stems and roots, and optimum and maximum yield of photosystem II, and chlorophyll index) and nutrition uptake (concentration of potassium and phosphorus elements in leaves).
Results: The results revealed that with the decrease in soil water content, the traits of leaf number, root and leaf fresh weight, relative water content, photosystem II performance, leaf chlorophyll index and leaf potassium and phosphorus content decreased and root length and electrolyte leakage rate increased. The increase of soil phosphorus in the high irrigated seedlings (60 percent of field capacity) caused the development of aerial organs and leaf surface, and in the seedlings that were in water deficit conditions, it caused the maximum performance of photosystem II to be maintained. Increasing soil phosphorus in all water conditions increased phosphorus, potassium and chlorophyll index, in the leaves of brant’s oak, but it had no effect on reducing membrane damage caused by oxidative stress.
Conclusion: In general, application of phosphorus increased the resistance of brant’s oak seedlings to drought stress by improving nutritional status and protecting the photosynthetic apparatus. Implementing higher concentrations of phosphorus is suggested for future research in order to study the possibility of improving water relations and protecting against plasma membrane injury.
