تأثير عمليات پرورشي بر جست‌زني تاغ به منظور تعيين بهترين زمان و ارتفاع هرس (مطالعۀ موردي: تاغزارهاي دست‌كاشت اشتهارد)

The effect of Silviculture on Tillering Haloxylon to determine the best height and time pruning (Case study: haloxylon plantation in eshtehard)

ﮔﻮﻧﮥ ﺗﺎغ از ﮔﯿﺎﻫﺎن ﻣﻘﺎوم در روﯾﺸﮕﺎهﻫﺎي ﻣﻨﺎﻃﻖ ﺑﯿﺎﺑ ـﺎﻧﯽ اﺳ ـﺖ ﮐ ـﻪ از زﻣ ـﺎن ﮐﻨﺘ ـﺮل ﻣﺎﺳﻪﻫﺎي روان ﺑﻪﻋﻨﻮان ﯾﮑﯽ از راهﺣﻞﻫ ـﺎي ﻣﺒ ـﺎرزه ﺑﺎ ﻓﺮﺳﺎﯾﺶ و ﺗﺜﺒﯿﺖ ﺷﻦ ﺑﺎ روش ﺑﯿﻮﻟﻮژﯾﮏ ﻫﻤﻮاره ﻣ ـﺪ ﻧﻈ ـﺮ ﻣﺤﻘﻘﺎن و دﺳ ـﺖاﻧ ـﺪرﮐﺎران ﺑ ـﻮده اﺳ ـﺖ. در اﯾﻦ ﺗﺤﻘﯿﻖ ﮐﻪ در ﺟﻨﮕﻞﻫﺎي دﺳﺖﮐﺎﺷﺖ اﺷﺘﻬﺎرد ﺻﻮرت ﮔﺮﻓﺖ، اﺛﺮ زﻣﺎن و ارﺗﻔﺎع ﻫﺮس ﺑﺮ ﭘﺎﯾﻪﻫﺎﯾﯽ از ﺗﺎغ ﮐﻪ آﺛﺎر ﭘﮋﻣﺮدﮔﯽ و ﺧﺸﮑﯿﺪﮔﯽ در آنﻫﺎ ﻗﺎﺑﻞ ﻣ ﺸﺎﻫﺪه ﺑﻮد، ﻣﻮرد ﺑﺮر ﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. اﯾﻦ ﭘﮋوﻫﺶ در ﻗﺎﻟﺐ آزﻣﺎﯾﺶ ﻓﺎﮐﺘﻮرﯾﻞ ﺑﺮ ﻣﺒﻨﺎي ﻃﺮح ﮐﺎﻣﻼً ﺗ ﺼﺎدﻓﯽ ﺑﺎ ﭼﻬﺎر ﺗﯿﻤﺎر ا ﺻﻠﯽ زﻣﺎن ﻫﺮس )ﻣﺮداد، آﺑﺎن، دي، ا ﺳﻔﻨﺪ( و ﭼﻬﺎر ﺗﯿﻤﺎر ﻓﺮﻋﯽ ارﺗﻔﺎع ﻫﺮس )ﻫﺮس ﮐﻒﺑﺮ، 25 ﺳﺎﻧﺘﯽﻣﺘﺮ، 50 و 75 ﺳﺎﻧﺘﯽﻣﺘﺮ( اﺟﺮا ﺷﺪ. ﻗﺒﻞ از اﻋﻤﺎل ﻫﺮس، ﺟﻬﺖ ﻫﻤﮕﻦ و ﻫﻢ اﻧﺪازه ﺑﻮدن ﭘﺎﯾﻪﻫﺎ، ﻣﺘﻐﯿﺮﻫﺎي ارﺗﻔﺎع، ﻗﻄﺮ ﺗﺎج و ﻗﻄﺮ ﯾﻘﻪ در ﻣﻮرد ﻫﺮ ﭘﺎﯾﻪ اﻧﺪازهﮔﯿﺮي ﺷـــﺪ. اواﺧﺮ ﺗﯿﺮ ﻣﺎه ﻫﻤﺎن ﺳﺎل وﺿﻌﯿﺖ ﭘﺎﯾﻪﻫﺎ از ﻟﺤﺎظ ﺟﺴﺖزﻧﯽ ﯾﺎ ﻋﺪم ﺟﺴﺖ ﺑﺮرﺳﯽ ﮔﺮدﯾﺪ و وﯾﮋﮔﯽﻫﺎي ﮐﻤﯽ ﺟﺴﺖ، ﻫﻤﭽﻮن ﺗﻌﺪاد، ارﺗﻔﺎع و ﻗﻄﺮ ﺟﺴﺖﻫﺎ در ﻫﺮ ﭘﺎﯾﻪ اﻧﺪازهﮔﯿﺮي ﺷﺪ. ﻧﺘﺎﯾﺞ ﺣﺎﮐﯽ از آن ﺑﻮد ﮐﻪ ﻫﺮس ﺑﺎﻋﺚ ﺗﺤﺮﯾﮏ ﺟﺴﺖزﻧﯽ ﺷﺪه اﺳﺖ، ﭼﺮا ﮐﻪ 97/5 درﺻﺪ از ﭘﺎﯾﻪﻫﺎ داراي ﺟﺴﺖ ﺑﻮدﻧﺪ. ﻫﺮس در دي ﻣﺎه از ارﺗﻔﺎع 75 ﺳﺎﻧﺘﯽﻣﺘﺮ ﺑﺎ ﺗﻌﺪاد 100 ﺟﺴﺖ ﺑﯿﺸﺘﺮﯾﻦ ﺗﻌﺪاد ﺟﺴﺖ را دارا ﻣﯽﺑﺎﺷﺪ. ﮐﻤﺘﺮﯾﻦ ﺗﻌﺪاد ﻣﺮﺑﻮط ﺑﻪ ﻫﺮس ﮐﻒﺑﺮ در آﺑﺎن ﻣﺎه ﺑﺎ ﺗﻌﺪاد 5 ﺟﺴــﺖ ﻣﯽﺑﺎﺷــﺪ. از ﻟﺤﺎظ ارﺗﻔﺎع ﺟﺴــﺖ، ﻫﺮس در دي ﻣﺎه از ارﺗﻔﺎع 50 و 75 ﺳــﺎﻧﺘﯽﻣﺘﺮ ﺑﺰرﮔﺘﺮﯾﻦ ﺟﺴﺖﻫﺎ را دارا ﺑﻮد. ﺣﺪاﻗﻞ ارﺗﻔﺎع ﺟﺴﺖ ﻧﯿﺰ ﻣﺮﺑﻮط ﺑﻪ ﻫﺮس ﮐﻒﺑﺮ در زﻣﺎنﻫﺎي ﻣﺨﺘﻠﻒ ﻣﯽﺑﺎﺷﺪ. از ﻟﺤﺎظ ﻗﻄﺮ ﺟﺴﺖ ﺗﻔﺎوت ﻣﻌﻨﯽداري ﺑﯿﻦ ﺗﯿﻤﺎرﻫﺎ وﺟﻮد ﻧﺪارد، اﻣﺎ در ﮐﻞ ﻫﺮس در دي ﻣﺎه ﻗﻄﻮرﺗﺮﯾﻦ ﺟﺴـﺖﻫﺎ را ﺑﻪ ﺧﻮد اﺧﺘﺼـﺎص داده اﺳـﺖ. ﺑﻨﺎﺑﺮاﯾﻦ ﻣﯽﺗﻮان ﮔﻔﺖ ﻫﺮس در دي ﻣﺎه از ارﺗﻔﺎع 75 ﺳﺎﻧﺘﯽﻣﺘﺮ ﺑﻪ ﻋﻨﻮان ﺑﻬﺘﺮﯾﻦ زﻣﺎن و ارﺗﻔﺎع ﻫﺮس ﻣﯽﺑﺎﺷﺪ.

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.