اثر ﻣﺎﻟﭻﻫﺎي ﻣﺨﺘﻠﻒ ﺑﺮ ﮐﺎﻫﺶ ﺗﺒﺨﯿﺮ و ﺗﻐﯿﯿﺮات ﺷﻮري در ﺧﺎك ﻫﺎﯾﯽ ﺑﺎ ﺑﺎﻓﺖ ﻣﺘﻔﺎوت

Effect of different mulches on evaporation reduction and salinity changes in soils with different texture

ﮐﺎﻫﺶ ﺗﻠﻔﺎت آﺑﯿﺎري ﺗﺒﺨﯿﺮ ﺳﻄﺤﯽ ﺑﺎ اﺳﺘﻔﺎده از ﻻﯾﻪ ﻣﺎﻟﭻ در ﺳﻄﺢ ﺧﺎك ﻣﯽﺗﻮاﻧﺪ ﮐﻤﮏ ﻗﺎﺑﻞﺗﻮﺟﻬﯽ در ﺣﻔﻆ آب در ﺷﺮاﯾﻂ ﮐﻨﻮﻧﯽ ﮐـﻪ ﮐﺸـﻮرﻣﺎن دﭼﺎر ﮐﻤﺒﻮد آب اﺳﺖ، داﺷﺘﻪ ﺑﺎﺷﺪ. در ﭘﮋوﻫﺶ ﺣﺎﺿﺮ، اﺛﺮ ﺳﻪ ﻧﻮع ﻣﺎﻟﭻ در ﮐﺎﻫﺶ ﺗﺒﺨﯿﺮ در ﺳﻪ ﺧﺎك ﻟﻮم ﺷﻨﯽ، ﻟﻮم و ﻟﻮم رﺳﯽ ﺑﺮرﺳﯽ ﺷﺪ. ﺑﺪﯾﻦ ﻣﻨﻈـﻮر ﻻﯾﻪ ﺳﻪ ﺳﺎﻧﺘﯽﻣﺘﺮي از ﻣﺎﻟﭻﻫﺎ )ﻻﯾﻪ آﺑﮕﺮﯾﺰ، ﺳﻨﮕﺮﯾﺰه رﯾﺰ و ﮐﻮد داﻣﯽ( در ﺳﻄﺢ ﺧﺎك ﻗﺮار داده ﺷﺪه و اﺛﺮ آنﻫﺎ ﻫﻤﺮاه ﺑﺎ ﯾﮏ ﺷﺎﻫﺪ )ﺑﺪون ﻻﯾﻪ ﻣﺎﻟﭻ( ﺑـﺮ ﻣﯿﺰان ﺗﺒﺨﯿﺮ از ﻻﯾﺴﯿﻤﺘﺮﻫﺎي ﮐﻮﭼﮏ در ﻣﺰرﻋﻪاي در ﺷﻬﺮﺳﺘﺎن ﯾﺰد ﺑﺮرﺳﯽ ﮔﺮدﯾﺪ. آزﻣﺎﯾﺶﻫﺎ ﺑﻪﺻﻮرت ﻓﺎﮐﺘﻮرﯾﻞ در ﻗﺎﻟﺐ ﻃﺮح ﺑﻠﻮكﻫﺎي ﮐﺎﻣﻞ ﺗﺼﺎدﻓﯽ ﺑﺎ ﭼﻬﺎر ﺗﯿﻤﺎر و در ﺳﻪ ﺗﮑﺮار اﺟﺮا ﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎندﻫﻨﺪه ﮐﺎﻫﺶ ﻣﻌﻨﯽدار ﻣﻘﺪار ﺗﺒﺨﯿﺮ در ﻫﺮ ﺳﻪ ﺧﺎك داراي ﻻﯾﻪ ﺳﻄﺤﯽ ﻣﺎﻟﭻ ﺑـﻮد. ﻫﻤﭽﻨـﯿﻦ ﺑﯿﺸـﺘﺮﯾﻦ ﻣﯿﺰان ﮐﺎﻫﺶ ﺗﺒﺨﯿﺮ در ﻣﺎﻟﭻ ﺳﻨﮕﺮﯾﺰه رﯾﺰ ﻧﺴﺒﺖ ﺑﻪ ﺗﯿﻤﺎر ﺷﺎﻫﺪ در ﺧﺎكﻫﺎي ﻟﻮم ﺷﻨﯽ، ﻟﻮم و ﻟﻮمرﺳﯽ ﺑﻪﺗﺮﺗﯿﺐ 58/2 ،59/8 و 61/4 درﺻﺪ ﺑﻮد. ﭘـﺲ از ﻣﺎﻟﭻ ﺳﻨﮕﺮﯾﺰه رﯾﺰ، ﮐﺎراﯾﯽ ﻣﺎﻟﭻ ﮐﻮد داﻣﯽ ﺑﯿﺸﺘﺮ از ﻣﺎﻟﭻ ﻻﯾﻪ آﺑﮕﺮﯾﺰ ﺑﻮد. اﺛﺮ ﻣﺎﻟﭻ ﻫﺎ ﺑﺮ ﺗﻐﯿﯿﺮات ﺷﻮري در ﻋﻤﻖ ﺧﺎك ﻣﺘﻔﺎوت ﺑﻮد ﺑﻪ ﻃـﻮر ي ﮐـﻪ در ﺗﯿﻤـﺎر ﻣﺎﻟﭻ ﺳﻨﮕﺮﯾﺰه رﯾﺰ و ﮐﻮد داﻣﯽ ﮐﻤﺘﺮﯾﻦ ﻣﻘﺪار ﺷﻮري در ﺳﻄﺢ ﻫﺮ ﺳﻪ ﺧﺎك ﻣﺸﺎﻫﺪه ﺷﺪ. ﻣﺎﻟﭻ آﺑﮕﺮﯾﺰ اﺛﺮ ﮐﻤﺘﺮي در ﮐﺎﻫﺶ ﺷﻮري ﺧﺎك ﺳﻄﺤﯽ ﻧﺴـﺒﺖ ﺑﻪ دو ﻣﺎﻟﭻ دﯾﮕﺮ داﺷﺖ و ﻣﻘﺪار ﺑﯿﺸﺘﺮي از ﻧﻤﮏ ﻫﺎ از ﻋﻤﻖ ﺑﻪ ﺳﻄﺢ ﺧﺎك اﻧﺘﻘﺎل ﯾﺎﻓﺘﻪ ﺑﻮدﻧﺪ.

Reducing irrigation losses due to surface evaporation using mulch layer on soil surface can help in maintaining water in the current situation that our country is suffering from water deficit. In this research, the effect three types of mulch layer on evaporation reduction was evaluated on three soil textures (sandy loam, loam and clay loam). For this purpose, a layer of three centimeters mulches (water repellent layer, fine gravel and manure) was placed on the soil surface, and their effect and control (without mulch layers) on the evaporation rate of small lysimeters in Yazd city was investigated. The experiments were performed in a in a factorial experiment with completely randomized design with four treatments and three replications. The results showed that the surface mulch layer significantly decreased evaporation in the mentioned three soils. The maximum evaporation reduction in fine gravel layer compared to the control was 59.8, 58.2 and 61.4% in the sandy loam, loam and clay loam soil, respectively. After fine gravel, the manure was more effective than the water repellent layer mulch in evaporation reduction. The effect of mulches on salinity changes in soil depth was different, so that the lowest amount of salinity was observed in the treatment of fine gravel and manure mulches on the surface of the three soils. Water repellent mulch had less effect on reducing the salinity of topsoil than the other two mulches and more salts were transferred from the depth to the soil surface.