sadegh hoseinniaee; Hossein Azarnivand; Mohammad Jafari; Mohammad Ali Zare Chahouki
Abstract
Haloxylon is one of the resistant plants in desert areas, which has always been considered by researchers and practitioners since controlling sandy soils as one of the solutions to erosion and sand fixation by biological methods. In this study was conducted in forest plantations eshtehard, Bases of haloxylon ...
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Haloxylon is one of the resistant plants in desert areas, which has always been considered by researchers and practitioners since controlling sandy soils as one of the solutions to erosion and sand fixation by biological methods. In this study was conducted in forest plantations eshtehard, Bases of haloxylon thate wilting and drying effects are visible, was chosen and pruning them. This factorial experiment based on completely randomized design with four treatments, pruning time (September, October, December, February) and four sub-plots pruning height (Complete pruning, 25 cm, 50 and 75 cm) were implemented. Before applying pruning, for homogeneous and the same size the bases, Variable height, canopy cove diameter and crown diameter was measured on every base. The end of July condition bases was investigated in terms of Tillering and not tillering. Results showed that pruning stimulates been tillering. Because 97.5 percentage of bases was tillering. Pruning in January from height of 75 cm with 100 tiller hade the greatest number tiller. The lowest tiller regarding of November with 5 tiller. There is no significant difference between treatments in term of tiller diameter, but in general thickest tiller was for pruning in January. Therefore, it can be said that pruning is about 75 centimeters in December as the best pruning time and heigh.
Morteza Khodagholi; Razieh Saboohi
Abstract
The genus of Astragalus accounts for 31.4 percent of area of Isfahan Province with Astragalus verus Olivier as a foremost species. This study aimed to investigate the contributing climatic variables to distribution of this species. Moreover, the trends of climatic variables and their influence on the ...
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The genus of Astragalus accounts for 31.4 percent of area of Isfahan Province with Astragalus verus Olivier as a foremost species. This study aimed to investigate the contributing climatic variables to distribution of this species. Moreover, the trends of climatic variables and their influence on the species mortality. In doing so, 56 climatic variables relating to January, March, July, and the entire year were utilized. The Principal Component Analysis was employed to trim down the number of variables and their trends were analyzed using the Mann-Kendall test. The correlation analysis was ultimately used to investigate the association between climatic changes and mortality of Astragalus verus. Results showed that cooling temperature contributed most in the distribution of the species. The trend of temperature also indicated that mean temperature followed an upwards trend in most months of the year. Except Ardestan, Isfahan, Eastern Isfahan, and Kaboutar-Abad, annual precipitation declined but not significantly at the level of 1 and 5 percent. The dried up stands observed in Naeen region was estimated to be around 25 percent where the largest decreasing precipitation and increasing temperature was recorded. This estimate was only around 8 percent in Khansar and Chadegan whose increasing temperature and wind speed as well as decreasing precipitation were compensated by having a good growing potential.
