هدررفت خاك، كربن آلي، فسفر و پتاسيم در اثر فرسايش بين شياري متأثر از سرعت باد و سطوح مختلف خاكپوش بقاياي گياهي

ﺳﺎﺑﻘﻪ و ﻫﺪف: ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري ﯾﮑﯽ از اﻧﻮاع ﻣﻬﻢ ﻓﺮﺳﺎﯾﺶ ﺧﺎك در اراﺿﯽ ﮐﺸﺎورزي اﺳﺖ ﮐﻪ ﺑﺎﻋﺚ اﻓﺖ ﮐﯿﻔﯽ و ﻫﺪررﻓﺖ ﮐﻤﯽ ﺧﺎك ﻣﯽ ﺷﻮد. ﻫﺮﭼﻨﺪ ﭘﮋوﻫﺶ ﻫﺎي ﻣﺘﻌﺪدي در زﻣﯿﻨﻪ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري اﻧﺠﺎم ﺷﺪه، ﻣﻄﺎﻟﻌﺎت ﺑﺴﯿﺎر ﮐﻤﯽ در ﻣﻮرد ﻫﺪررﻓﺖ ﺧﺎك، ﻣﻮاد آﻟﯽ و ﻋﻨﺎﺻﺮ ﻏﺬاﯾﯽ در اﺛﺮ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري در ﺷﺮاﯾﻂ ﺑﺎران ﻣﺘﺄﺛﺮ از ﺑﺎد ﺻﻮرت ﮔﺮﻓﺘﻪ اﺳﺖ. ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﺑﺎ ﻫﺪف ﺑﺮرﺳﯽ ﺗﺄﺛﯿﺮ درﺻﺪﻫﺎي ﻣﺨﺘﻠﻒ ﺧﺎﮐﭙﻮش ﮐﺎه و ﮐﻠﺶ ﮔﻨﺪم در ﺗﻘﺎﺑﻞ ﺑﺎ ﺳﺮﻋﺖ ﻫﺎي ﻣﺨﺘﻠﻒ ﺑﺎد ﺑﺮ ﻫﺪررﻓﺖ ﺧﺎك، ﮐﺮﺑﻦ آﻟﯽ، ﻓﺴﻔﺮ و ﭘﺘﺎﺳﯿﻢ در اﺛﺮ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري روي دو ﺧﺎك زراﻋﯽ ﻣﺨﺘﻠﻒ اﻧﺠﺎم ﺷﺪ. ﻣﻮاد و روش ﻫﺎ: آزﻣﺎﯾﺶ ﺑﻪ ﺻﻮرت ﻓﺎﮐﺘﻮرﯾﻞ در ﻗﺎﻟﺐ ﻃﺮح ﮐﺎﻣﻼً ﺗﺼﺎدﻓﯽ و ﺑﺎ اﻋﻤﺎل ﺳﻪ ﻓﺎﮐﺘﻮر اﻧﺠﺎم ﺷﺪ. دو ﻧﻤﻮﻧﻪ ﺧﺎك زراﻋﯽ ﺑﺎ ﺣﺪاﮐﺜﺮ اﻧﺪازه ذرات 2 و 4/75 ﻣﯿﻠﯽ ﻣﺘﺮ، در ﺳﺮﻋﺖ ﻫﺎي ﻣﺨﺘﻠﻒ ﺑﺎد )ﺻﻔﺮ، 6 و 12 ﻣﺘﺮ ﺑﺮ ﺛﺎﻧﯿﻪ( و ﭼﻬﺎر ﺳﻄﺢ ﺧﺎﮐﭙﻮش ﮐﺎه و ﮐﻠﺶ ﮔﻨﺪم ﺷﺎﻣﻞ ﺻﻔﺮ، 30، 60 و 90 درﺻﺪ )ﻣﻌﺎدل 800، 1650 و 3300 ﮐﯿﻠﻮﮔﺮم در ﻫﮑﺘﺎر(، ﻫﺮ ﯾﮏ در ﺳﻪ ﺗﮑﺮار ﻣﻮرد آزﻣﺎﯾﺶ ﺷﺒﯿﻪ ﺳﺎزي ﺑﺎران و ﺑﺎد ﻗﺮار ﮔﺮﻓﺖ. ﺑﻪ اﯾﻦ ﻣﻨﻈﻮر، ﺑﺎران ﺑﺎ ﺷﺪت ﺛﺎﺑﺖ 40 ﻣﯿﻠﯽ ﻣﺘﺮ در ﺳﺎﻋﺖ ﺑﻪ ﻣﺪت 40 دﻗﯿﻘﻪ اﯾﺠﺎد و ﻣﯿﺰان ﻫﺪررﻓﺖ ﺧﺎك، ﮐﺮﺑﻦ آﻟﯽ، ﻓﺴﻔﺮ ﻗﺎﺑﻞ اﺳﺘﻔﺎده و ﭘﺘﺎﺳﯿﻢ ﻗﺎﺑﻞ ﺟﺬب اﻧﺪازه ﮔﯿﺮي ﺷﺪ. در ﻧﻬﺎﯾﺖ، ارﺗﺒﺎط ﺷﺪت ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري ﻣﺘﺄﺛﺮ از ﺑﺎد ﺑﺎ ﻫﺪررﻓﺖ ﮐﺮﺑﻦ آﻟﯽ و ﻋﻨﺎﺻﺮ ﻏﺬاﯾﯽ ﺑﺮرﺳﯽ ﺷﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻫﺪررﻓﺖ ﺧﺎك، ﮐﺮﺑﻦ آﻟﯽ، ﻓﺴﻔﺮ ﻗﺎﺑﻞ اﺳﺘﻔﺎده و ﭘﺘﺎﺳﯿﻢ ﻗﺎﺑﻞ ﺟﺬب در اﺛﺮ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري در ﺧﺎك ﻫﺎي ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﯿﻦ 8/1 ﺗﺎ 134/9، 0/02 ﺗﺎ 1/28، 0/03×10-3 ﺗﺎ 1/45×10-3 و 0/007 ﺗﺎ 0/160 ﻣﯿﻠﯽ ﮔﺮم ﺑﺮ ﻣﺘﺮ ﻣﺮﺑﻊ در ﺛﺎﻧﯿﻪ ﻣﺘﻐﯿﺮ ﺑﻮد. ﺑﺎ اﻓﺰاﯾﺶ درﺻﺪ ﺧﺎﮐﭙﻮش، ﻣﯿﺰان ﻫﺪررﻓﺖ ﺧﺎك، ﮐﺮﺑﻦ آﻟﯽ و ﻋﻨﺎﺻﺮ ﻏﺬاﯾﯽ ﺑﻪ ﻃﻮر ﻣﻌﻨﯽ داري ﮐﺎﻫﺶ ﯾﺎﻓﺖ. در ﻣﻘﺎﺑﻞ، اﻓﺰاﯾﺶ ﺳﺮﻋﺖ ﺑﺎد، ﺑﺎﻋﺚ اﻓﺰاﯾﺶ ﻣﻌﻨﯽ دار ﻫﺪررﻓﺖ ﺧﺎك و ﻋﻨﺎﺻﺮ ﻏﺬاﯾﯽ ﺷﺪ. ﻫﺪررﻓﺖ ﺧﺎك، ﮐﺮﺑﻦ آﻟﯽ و ﻋﻨﺎﺻﺮ ﻏﺬاﯾﯽ در اﺛﺮ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري در ﺷﺮاﯾﻂ ﻋﺪم وزش ﺑﺎد و ﻋﺪم وﺟﻮد ﺧﺎﮐﭙﻮش، ﺑﺎ اﻓﺰاﯾﺶ اﻧﺪازه ﺧﺎﮐﺪاﻧﻪ ﻫﺎ ﮐﺎﻫﺶ ﯾﺎﻓﺖ. در ﻫﺮ دو ﺧﺎك ﻣﻮرد ﻣﻄﺎﻟﻌﻪ، ﻫﺪررﻓﺖ ﮐﺮﺑﻦ آﻟﯽ ﺑﯿﺶ ﺗﺮ از ﻫﺪررﻓﺖ ﻓﺴﻔﺮ و ﭘﺘﺎﺳﯿﻢ ﺑﻮد. ارﺗﺒﺎط ﻫﺪررﻓﺖ ﺧﺎك ﺑﺎ ﻫﺪررﻓﺖ ﮐﺮﺑﻦ آﻟﯽ و ﻧﯿﺰ ﺑﺎ ﻫﺪررﻓﺖ ﻓﺴﻔﺮ، ﻗﻮي ﺗﺮ از ارﺗﺒﺎط ﺑﺎ ﻫﺪررﻓﺖ ﭘﺘﺎﺳﯿﻢ ﺑﻮد.ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﯾﺎﻓﺘﻪ ﻫﺎي اﯾﻦ ﭘﮋوﻫﺶ ﻧﺸﺎن داد ﮐﻪ وزش ﺑﺎدﻫﺎي ﻓﺮﺳﺎﯾﻨﺪه در زﻣﺎن وﻗﻮع ﺑﺎرش ﺑﺎران، ﻣﯽ ﺗﻮاﻧﺪ ﻫﺪررﻓﺖ ﺧﺎك، ﮐﺮﺑﻦ آﻟﯽ، ﻓﺴﻔﺮ ﻗﺎﺑﻞ اﺳﺘﻔﺎده و ﭘﺘﺎﺳﯿﻢ ﻗﺎﺑﻞ ﺟﺬب در اﺛﺮ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري را اﻓﺰاﯾﺶ دﻫﺪ. ﻫﺮ ﭼﻨﺪ وزش ﺑﺎد ﺑﺎﻋﺚ اﻓﺰاﯾﺶ ﻗﺪرت ﺟﺮﯾﺎن رواﻧﺎب و ﺗﺸﺪﯾﺪ ﻫﺪررﻓﺖ ﻣﯽ ﺷﻮد وﻟﯽ وﺟﻮد ﺧﺎﮐﭙﻮش ﺑﺎ اﯾﺠﺎد زﺑﺮي در ﺳﻄﺢ و ﻧﯿﺰ ﻣﺤﺎﻓﻈﺖ ﺧﺎك ﺳﻄﺤﯽ از ﺑﺮﺧﻮرد ﻣﺴﺘﻘﯿﻢ ﻗﻄﺮات ﺑﺎران، ﻣﯿﺰان ﻫﺪررﻓﺖ را ﮐﺎﻫﺶ ﻣﯽ دﻫﺪ. ﺑﺮ اﺳﺎس ﯾﺎﻓﺘﻪ ﻫﺎي اﯾﻦ ﭘﮋوﻫﺶ، ﺑﻬﺘﺮﯾﻦ ﻣﯿﺰان ﺧﺎﮐﭙﻮش ﮐﺎه و ﮐﻠﺶ ﮔﻨﺪم ﺑﺮاي ﮐﻨﺘﺮل ﻫﺪررﻓﺖ ﺧﺎك در اﺛﺮ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري ﺑﺮاﺑﺮ ﺑﺎ 60 درﺻﺪ ﺗﻌﯿﯿﻦ ﺷﺪ. ﺑﻨﺎﺑﺮاﯾﻦ ﺣﻔﻆ و ﯾﺎ اﯾﺠﺎد اﯾﻦ ﻣﯿﺰان ﭘﻮﺷﺶ ﺳﻄﺤﯽ در اراﺿﯽ ﮐﺸﺎورزي ﻣﯽ ﺗﻮاﻧﺪ ﺗﺎ ﺣﺪ زﯾﺎدي از ﻫﺪررﻓﺖ ﺧﺎك، ﮐﺮﺑﻦ آﻟﯽ و ﻋﻨﺎﺻﺮ ﻏﺬاﯾﯽ در اﺛﺮ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري ﻣﺘﺄﺛﺮ از وزش ﺑﺎد ﺟﻠﻮﮔﯿﺮي ﮐﻨﺪ.

Background and Objectives: Interrill erosion is one of the most important forms of soil erosion in agricultural lands let to decline in the quality and loss of soil. Despite many studies have been done on interrill erosion, few studies have been conducted on the losses of soil, organic carbon (OC) and nutrients due to wind-driven interrill erosion. Therefore, the purpose of this study is to investigate the effects of different percentages of wheat straw coverage and wind velocities on the losses of soil, OC, phosphorus (P) and potassium (K) following to wind-driven interrill erosion on two contrasting cropland soil samples. Materials and Methods: the experiment was conducted as factorial in a completely randomized design using three factors. Two soil samples with maximum aggregate sizes of 2 and 4.75 mm covered by four levels of wheat straw mulch including 0 (as control), 30, 60, 90% (equal to 800, 1650, and 3300 kg ha-1) were examined at different wind velocities (0, 6 and 12 m s-1), each at three replicates under simulated rain and wind. Therefore, a constant intensity rainfall of 40 mm/h was generated for 40 minutes and the amount of soil losses, as well as OC, P and K losses were measured. Finally, the relationship of wind-driven interrill erosion rate with the OC, P, and K losses was evaluated. Results: The results showed that the loss of soil, OC, P, and K In the studied soils ranged from 8.1 to 134.9, 0.02 to 1.28, 0.03×10-3 to 1.45×10-3, and 0.007 to 0.160 mg m-2 s-1, respectively. With increasing the percentage of mulch, the losses were reduced significantly as nonlinear trends. In contrast, higher wind velocities increased the losses of soil and the nutrients. In the absence of wind and coverage, fewer losses were found in the soil containing coarser aggregates. The OC loss in the soils was higher than the P and K losses. The relationship of soil loss with OC and P losses was closer than that with the K loss. Conclusion: The findings of this study showed that blowing of erosive winds during a rainfall can intensify the loss of soil and nutrients. However, wind velocity enhances stream power; the presence of surface mulch can reduce the losses by enhancing the surface roughness and conserving the soil surface from the direct impact of raindrops. Moreover, the presence of larger aggregates at the soil surface has an effective influence on the interrill erosion control. Based on the findings of this study, 60% was determined as the optimal coverage of wheat straw to control soil loss due to interrill erosion. Therefore, keeping this amount of plant residue coverage on agricultural soils can considerably constrain the losses of soil and nutrients due to interrill erosion