ﺑﺮرﺳﯽ اﻣﮑﺎن ﮐﺎرﺑﺮد دزﻫﺎي ﮐﺎﻫﺶ ﯾﺎﻓﺘﻪ ﻧﯿﮑﻮﺳﻮﻟﻔﻮرون+ﺗﻮ، ﻓﻮر-دي ﺑﻪ ﻫﻤﺮاه ﮐﻮد ﻧﯿﺘﺮوژن در ﺳﻮرﮔﻮم ﻋﻠﻮﻓﻪ ايSorghum bicolor (L.) Moench

Investigating the possibility of application of reduced doses of nicosulfuron+2, 4-D integrated with nitrogen fertilizer in forage Sorghum(Sorghum bicolor (L.) Moench)

از آن ﺟﺎ ﮐﻪ ﺳﻮرﮔﻮم ﺑﻪ ﺑﺴﯿﺎري از ﻋﻠﻒ ﮐﺶ ﻫﺎي راﯾﺞ ﺗﺤﻤﻞ ﮐﺎﻓﯽ ﻧﺪارد، ﺗﻌﯿﯿﻦ ﻣﯿﺰان ﻣﻨﺎﺳﺐ ﻋﻠﻒ ﮐﺶ ﺑﻪ ﻣﻨﻈﻮر ﻣﻬﺎر ﻋﻠﻒ ﻫﺎي ﻫﺮز در آن از ﺿﺮورت ﺑﺎﻻﯾﯽ ﺑﺮﺧﻮردار اﺳﺖ. ﺑﺪﯾﻦ ﻣﻨﻈﻮر آزﻣﺎﯾﺸﯽ ﺑﻪ ﺻﻮرت ﻓﺎﮐﺘﻮرﯾﻞ در ﻗﺎﻟﺐ ﻃﺮح ﺑﻠﻮك ﻫﺎي ﮐﺎﻣﻞ ﺗﺼﺎدﻓﯽ ﺑﺎ ﺳﻪ ﺗﮑﺮار ﻃﺮاﺣﯽ ﺷﺪ.ﺗﯿﻤﺎرﻫﺎي آزﻣﺎﯾﺶ ﺷﺎﻣﻞ دو ﮔﯿﺎه ﺳﻮرﮔﻮم ﻋﻠﻮﻓﻪ اي )رﻗﻢ اﺳﭙﯿﺪ(، و ﺗﺎج ﺧﺮوس، دزﻫﺎي ﮐﺎﻫﺶ ﯾﺎﻓﺘﻪ دو ﻋﻠﻒ ﮐﺶ ﻧﯿﮑﻮﺳﻮﻟﻔﻮرون+ﺗﻮ، ﻓﻮر-دي)ﺑﻪ ﺗﺮﺗﯿﺐ 2+1 ﻟﯿﺘﺮ در ﻫﮑﺘﺎر ﺑﻪ ﻋﻨﻮان دز ﺗﻮﺻﯿﻪ ﺷﺪه و ﮐﺎرﺑﺮد ﺑﻪ ﺻﻮرت ﭘﺲ روﯾﺶ در ﻣﺮﺣﻠﻪ 4-2 ﺑﺮﮔﯽ ﮔﯿﺎﻫﺎن ﻣﻮرد ﻧﻈﺮ(، ﻫﺮ ﮐﺪام در 5 ﺳﻄﺢ )0، 0/25، 0/50، 0/75 و 100 درﺻﺪ دز ﺗﻮﺻﯿﻪ ﺷﺪه( و ﮐﻮد ﻧﯿﺘﺮوژن ﺷﺎﻣﻞ دزﻫﺎي ﮐﺎﻫﺶ ﯾﺎﻓﺘﻪ در 5 ﺳﻄﺢ )0، 0/25، 0/50، 0/75 و 100 درﺻﺪ دز ﺗﻮﺻﯿﻪ ﺷﺪه )400 ﮐﯿﻠﻮﮔﺮم اوره در ﻫﮑﺘﺎر(( ﺑﻮد. ﺑﺮرﺳﯽ ﭘﺎﺳﺦ ﺳﻮرﮔﻮم و ﺗﺎج ﺧﺮوس ﺑﻪ دز ﻋﻠﻒ ﮐﺶ ﻧﯿﮑﻮﺳﻮﻟﻔﻮرون+ﺗﻮ، ﻓﻮر-دي در ﻫﺮ ﺳﻄﺢ ﮐﻮد ﻧﯿﺘﺮوژن )از ﻣﻨﺒﻊ اوره( ﺑﺎ اﺳﺘﻔﺎده از ﻣﻌﺎدﻟﻪ دز-ﭘﺎﺳﺦ اﺳﺘﺎﻧﺪارد ﻧﺸﺎن داد ﮐﻪ ﺑﺎ اﻓﺰاﯾﺶ دز ﻋﻠﻒ ﮐﺶ وزن ﺧﺸﮏ ﺳﻮرﮔﻮم و ﺗﺎج ﺧﺮوس ﮐﺎﻫﺶ ﯾﺎﻓﺖ.ﭘﯿﺶ ﺑﯿﻨﯽ ﻣﺪل از وزن ﺧﺸﮏ ﺳﻮرﮔﻮم و ﺗﺎج ﺧﺮوس ﺑﺎ ﻣﺼﺮف 0،/2 0/5و 1 ﻧﺴﺒﺖ از دز ﺗﻮﺻﯿﻪ ﺷﺪه ﻋﻠﻒ ﮐﺶ ﺑﺎ ﻣﺼﺮف ﺻﻔﺮ، 200 و 400 ﮐﯿﻠﻮﮔﺮم ﮐﻮد ﻧﯿﺘﺮوژن در ﻫﮑﺘﺎر ﺑﻪ ﺗﺮﺗﯿﺐ ﻣﻌﺎدل 1/31، 0/81 و 0/42 و 0/41 ،0/79 و 0/31ﮔﺮم در ﮔﻠﺪان ﺑﻮد. ﺑﻪ ﻃﻮرﮐﻠﯽ، ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﺑﺎ اﻓﺰاﯾﺶ ﻣﯿﺰان ﻣﺼﺮف ﮐﻮد ﻧﯿﺘﺮوژن، ﻣﻘﺪار ﻋﻠﻒ ﮐﺶ ﻣﻮرد ﻧﯿﺎز ﺑﻪ ﻣﻨﻈﻮر اﯾﺠﺎد 50 درﺻﺪ ﮐﺎﻫﺶ در وزن ﺧﺸﮏ ﺳﻮرﮔﻮم و ﺗﺎج ﺧﺮوس ﮐﺎﻫﺶ ﯾﺎﻓﺖ.

Since sorghum is not tolerated by many common herbicides, determining the right amount of herbicide to control weeds is very important. For this purpose, a factorial experiment was designed in a randomized complete block design with three replications. Experimental treatments included Sorghum and pigweed, reduced doses of nicosulfuron+2,4-D (1+2 L ha-1 as recommended dose and post-emergence at 2-4 leaf) at 5 levels (0, 0.25, 0.5, 0.75 and 100% as recommended dose) and nitrogen fertilizer including recommended dose at five levels (0, 0.25, 0.5, 0.75 and 100% as recommended dose (400 kg urea ha-1)).Evaluation of sorghum and pigweed response to the herbicide dose of nicosulfuron+2,4-D, at each level of nitrogen fertilizer using standard dose-response equation showed that dry weight of sorghum and pigweed decreased with increasing herbicide dose. Model prediction of sorghum and pigweed dry weight using 0.2, 0.5, and 1 ratios of recommended herbicide dose with 0, 200 and 400 kg N ha-1 equivalents of 1.31, 0.81 and 0.42 and 0.79, 0.41 and 0.31 g per pot, respectively. In general, the results showed that with increasing nitrogen fertilizer application, the amount of herbicide needed to cause a 50% decrease in dry weight of sorghum and pigweed was reduced