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Korean Journal of Environmental Agriculture Korean J Environ Agric. 2015;34(4):253259. Korean Online ISSN: 22334173 Published online 2015 November 5. http://dx.doi.org/10.5338/kjea.2015.34.4.39 Print ISSN: 12253537 Research Article Open Access 휴경기후작물재배에의한참외장기연작비닐하우스토양의제염효과 변일수, 정종배 * 대구대학교생명환경대학생명환경학부 Desalinization Effect of Offseason Crop Cultivation in Longterm Oriental Melon Cultivated Plastic Film House Soils IlSu Byeon and JongBae Chung * (Division of Life and Environmental Science, Daegu University, Gyeongsan 38453, Korea) Received: 2 August 2015 / Revised: 19 October 2015 / Accepted: 27 October 2015 Copyright c 2015 The Korean Society of Environmental Agriculture This is an OpenAccess article distributed under the terms of the Creative Commons Attribution NonCommercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ORCID JongBae Chung http://orcid.org/0000000252842272 Abstract BACKGROUND: During the offseason, the cultivation of Chinese cabbage and water dropwort is often used to desalinize plastic film house soils. The objective of this study was to verify the effect of doublecropping systems on the salt removal in oriental melon cultivated plastic film house soils. METHODS AND RESULTS: Electrical conductivity (EC) and soluble salt contents were measured in soils collected from plastic film houses of oriental melon cultivation before and after the offseason crop cultivation. Also the same measurements were performed in the next oriental melon season to estimate the desalinization effect of doublecropping systems. During the cultivation of Chinese cabbage under openfield condition, EC e of surface soil was reduced from 6.0 to 0.8 ds/m. Doublecropping of water dropwort in flooded soil was also efficient in removing the salts accumulated during oriental melon cultivation. In the house soils where salts were removed during the offseason crop cultivation, soil EC e was maintained below 3 ds/m during the next oriental melon cultivation season. *Corresponding author: JongBae Chung Phone: +82538506755; Fax: +82538506759; Email: jbchung@daegu.ac.kr CONCLUSION: The offseason cropping under openfield or flooded condition was effective in desalinization of plastic film house soils. Since the salt removal effect is not expected to last for several years, the doublecropping system should be introduced every season to maintain soil EC below the critical level. Key words: Desalinization, Offseason cropping, Oriental melon, Plastic film house soil, Soil salt 서론 우리나라참외재배면적은 2013년기준으로 5,515 ha이며, 그중에서시설재배면적은 5,380 ha로서전체의 97.6% 를차지하고있다 (2014년농림축산식품통계연보 ). 시설재배참외는일반적으로 121월경에정식하여 3월부터 7월까지수확하는데, 그후원줄기로부터다시순을키워 10월까지연장하여재배하기도한다. 시설농업은기술집약적이며여러농가가밀집하여주산지를형성하여특정작물을재배하므로동일포장에서다년간연작을하게된다. 따라서참외를비롯한각종시설재배작물주산지에서는염류의과다한집적과뿌리혹선충밀도의증가등연작에따른피해가심각하다 (Kang et al., 1996; Ha et al., 1997; Cho et al., 2000; Jun and Park, 2001; Kim, 2001). 전국의시설재배지를대상으로조사된결과를보면 (2004년농촌진흥청농업환경조사보고서 ), 전기전도도 (electrical conductivity, EC) 는표토와심토에서평균적으로각각 3.5 및 2.2 ds/m로심토에비해 253

254 Byeon et al. 표토에염류가많이집적되어있는것으로나타났고, 분포비율은 2 ds/m 이하가 41%, 24 ds/m 32%, 4 ds/m 이상이 27% 로서장해기준인 2 ds/m를초과하는비닐하우스가 59% 였다. 작물별로는오이, 참외, 호박등과채류재배지에서염류집적현상이더욱심한것으로조사되었다. 강우의유입이차단된비닐하우스토양에염류가집적되는것은불가피한현상이며, 화학비료와퇴비의과다시용, 작물생육에필요한수준의제한된관수등으로인해재배연수가길어질수록토양의염류집적현상이가중된다 (Jung et al., 1994; Jung et al., 1998; Jun and Park, 2001; Kim et al., 2006b). 비닐하우스토양에축적되는주요이온은 Ca 2+, Mg 2+, K +, NH + 4 등의양이온과 NO 3, SO 2 4, Cl, PO 3 4 등의음이온이다 (Jung et al., 1994; Ha et al., 1997; Chung et al., 2005; Kim et al., 2006b; Oh et al., 2010). 토양에과다하게염류가집적되면주로토양용액의삼투포텐셜저하로인한작물의수분흡수장해, 양분상호간농도차이에서따른길항적양분흡수장해, 식물체내의양분불균형에서나타나는각종영양생리장해등으로인해작물의생육이저해된다 (Marschner, 1986; Sparks, 1995; Kang et al., 1996). 하우스시설을철거하고일정기간벼나기타노지작물을재배한후다시시설재배로전환하는것이토양에집적된염류를충분히제거할수있는방법이지만재배용지의확보와시설이전에따른비용문제가제한요인이된다. 염류집적경감대책으로표토제거, 객토, 심토반전, 암거배수, 담수, 녹비작물재배등이이용되고있으나, 처리와시설에따른노동력과비용이농가에부담이되며염류재집적등문제점을가지고있는실정이다 (Kim et al., 2001; Jun et al., 2002; Kim et al., 2006a; Lee et al., 2013). 담수또는토양세척을통해시설재배토양의염류를효과적으로제거할수있는것으로보고되어있는데 (Jung and Yoo, 1975; Chung et al., 2008; Oh et al., 2010), 작은토주를이용한실험이나비닐 하우스내에서수행된소규모모형실험의결과이다. 담수는 1 회에 100 mm 내외로 2회이상반복해야염류제거효과있는것으로알려져있으며, 물소요량이많고배수나하층으로물의침투가원활한토양에만적용할수있는단점이있다. 토양을물로세척하는방법이염류제거에매우효과적이라고하는데 (Chung et al., 2008), 실제로농가에서작토층의토양전체를세척하는것은불가능하다. 한편주작물을수확한후휴경기에옥수수, 수단그라스, 호밀등의녹비작물이나기타작물을재배하여시설내토양중의잔류양분을제거함으로써토양염류집적을 1060% 저감시키는효과를거둘수있다 (Hwang et al., 1993; Kim et al., 2013; Lee et al., 2013). 최근전국적으로농업기술지도기관에서연작장해와염류제거를위해휴경기에녹비작물을재배하도록시설재배농가에권장하고있으며, 염류의집적정도가심한경우에는재배작물을수거하여반출하는것이바람직하다. 지금까지제시된여러가지염류제거방법가운데실제농가에서쉽게활용할수있는효과적인방법은없으며, 적정시비를통해과다한염류의투입을사전에차단하고농가별로활용가능한다양한방법을통해염류집적문제를해결해야한다. 휴경기에토양을담수상태로유지하거나강우에노출시킨조건에서녹비작물등을재배하면용탈작용과함께작물의흡수작용을통해더욱효과적으로비닐하우스토양의염류를제거할수있을것이다. 경북경산시압량면지역의참외시설재배단지에서는집적된염류를제거하기위해휴경기에후작으로비닐하우스에서담수상태로미나리를재배하거나천창비닐을걷어내고노지환경에서배추를재배한다. 개별농가에서실행하고있는이러한염류제거노력이얼마나효과적인지그리고그효과가얼마나지속될수있는지에대한검정이필요하다. 본연구에서는참외재배비닐하우스에서휴경기에담수조건에서후작물을재배하거나노지조건에서후작물을재배할 Table 1. Description of the cropping systems included in the experiment, and the numbers of plastic film house where soil samples were collected Cropping system Oriental melon single cropping Oriental melon Chinese cabbage double cropping Oriental melon water dropwort double cropping Soybean single cropping Description Longterm (more than 10 years) continuous orientalmelon single cropping exclusively under plastic film house conditions Oriental melon Chinese cabbage double cropping in longterm melon growing plastic film houses Oriental melon was grown under plastic film house conditions from DECember to July, and offseason crop Chinese cabbage was grown under openfield conditins from September to November. Oriental melon water dropwort double cropping in longterm oriental melon growing plastic film houses In plastic film houses, oriental melon was grown from December to July, and offseason crop water dropwort was grown from November to January under completely flooded conditions. Soybean single cropping system under open field conditions for more than 5 years No. of plastic film house or field 5 4 4 3

Desalinization Effect of Offseason Crop Cultivation 255 Table 2. Characteristics of soils collected after season of oriental melon single cropping system in plastic film houses and soybean single cropping system in open fields Cropping system Depth ph EC e* Organic matter Available P cm ds/m g/kg mg P 2O 5/kg Melon single cropping 020 7.63 ± 0.44 4.23 ± 1.55 28.3 ± 2.50 557.9 ± 104.3 2040 7.64 ± 0.37 1.79 ± 0.64 14.4 ± 1.93 221.1 ± 81.34 020 6.41 ± 0.83 1.08 ± 0.80 19.4 ± 6.68 371.9 ± 84.21 Soybean single cropping 2040 6.48 ± 0.63 0.84 ± 0.71 8.2 ± 5.94 100.7 ± 19.41 LSD 0.05 0.79 1.31 10.9 182.2 * EC e: Electrical conductivity of the saturation extract 경우잔류양분의흡수와용탈을통한토양염류제거효과를실제포장조건에서조사하였으며, 이러한작부체계가장기연작시설재배토양에대한효과적인염류제거수단으로활용될수있는지를평가하였다. 재료및방법 작부체계와토양시료채취경북경산시압량면지역참외재배단지에서 Table 1과같이다년간참외를단작으로재배해온비닐하우스, 참외와노지상태에서배추를재배한비닐하우스및참외와담수상태에서미나리를이모작한비닐하우스에서단기윤작의토양염류제거효과를조사하였다. 그리고배추나미나리재배를통한염류제거효과가다음작기참외재배기간에지속될수있는지를조사하였다. 조사대상참외단작비닐하우스 5개소에는참외 배추이모작농가와참외 미나리이모작농가에서동일한조건으로관리하는참외단작비닐하우스 1개소씩을포함시켜참외단작의경우와비교하여이모작체계의염류제거효과를조사하였다. 참외단작비닐하우스와콩재배노지포장의토양시료는참외와콩재배가종료된후인 2011년 10월초순에조사대상비닐하우스및포장별로 3개지점을선정하여 020 cm 및 2040 cm 깊이별로 500 g 정도의토양을채취하였다. 참외 배추및참외 미나리이모작체계의경우는각각배추재배가종료된 2011년 12월초순및미나리재배가종료된 2012년 1 월말에참외단작비닐하우스의경우와동일하게토양시료를채취하였다. 참외 배추및참외 미나리이모작체계에서다음작기참외재배기간동안토양염류집적변화를조사하기위하여참외단작, 참외 배추이모작및참외 미나리이모작체계를이용한농가의비닐하우스에서 2012년 4월부터 7월까지월 1회 020 cm 깊이토양시료를조사대상비닐하우스별로 3개지점에서채취하였다. 채취한토양시료는각각잘혼합한후일부를 NH + 4 과 NO 3 의분석을위해냉장보관하였으며, 나머지는풍건시킨후 2 mm 체에통과시켜분석용시료로사용하였다. 토양분석 ph는토양시료와증류수의 1:5 현탁액을이용하여유리전극 ph meter(mettler Delta 350, MettlerToledo GmbH, Urdorf, Switzerland) 로측정하였다. 토양포화침출액의전기전도도 (EC e) 는토양시료 250 g 정도를 500 ml 비커에담고증류수를가하여포화반죽상태로만든다음 10시간후원심분리기를이용하여토양용액을추출하여 conductivity meter(mate 90, Corning Co., Corning, New York, USA) 로측정하였다 (Rhoades, 1982). 유기물함량은 WalkleyBlack 방법으로측정하였고 (Nelson and Sommers, 1982), 유효인산은 Bray No. 1 침출용액으로추출한후몰리브덴청법으로발색시켜 spectrophotometer (UV1800, Shimadzu, Japan) 로정량하였다 (Olsen and Sommers, 1982). 토양의가용성염류를구성하는이온은토양시료와증류수를 1:5 비율로혼합하여 60분간진탕한다음 membrane filter(0.45μm pore size) 로여과하여추출하였다 (Rhoades, 1982). Ca 2+, Mg 2+, Na +, K + 는 ICP atomic emission spectrometer(varian 720ES Series, Varian, USA) 로측정하였다. 그리고 Cl 과 SO 2 4 는 ion chromatograph (DX120, Dionex, Germany) 로, NH + 4 과 NO 3 는 flow injection autoanalyzer(fiastar5000, FOSS Tecator, Höganäs, Sweden) 로측정하였다. 결과및고찰 참외연작비닐하우스와노지콩재배포장토양특성비교참외연작비닐하우스토양의특성을인근의노지콩재배포장과비교하여조사한결과는 Table 2와같았으며, 토성은비닐하우스별로대부분미사질식토이었고일부미사질식양토인경우도있었다. 참외를재배하는데적당한토양 ph는 6.06.5 정도인데 ( 고품질참외표준재배매뉴얼, 한국참외생산자협의회 ), 참외연작비닐하우스토양의 ph는 7.5 내외로높게나타났다. 참외연작비닐하우스토양에서 ph가이와같이높은것은염류의집적과함께퇴비시용량이많고참외재배후잔류작물체를태워서그재를토양에혼입시키거나석회물질을이용한토양열소독등에기인하는것으로판단된다.

256 Byeon et al. Table 3. Waterextractable ion contents in surface soils (020 cm) after season of oriental melon single cropping system in plastic film house and soybean single cropping system in open field Cropping system K + Ca 2+ Mg 2+ Na + NH 4 + cmol/kg Melon single cropping 0.38 1.11 0.66 0.43 0.17 0.41 1.19 0.62 Soybean single cropping 0.25 0.30 0.15 0.19 0.09 0.08 0.79 0.28 NO 3 SO 4 2 Cl Table 4. Comparison of soil characteristics after season of oriental melon single cropping system and oriental melonchinese cabbage double cropping system Cropping system Depth ph EC e* Available P cm ds/m P 2O 5 mg/kg Melon single cropping 020 7.57 ± 0.02 6.04 ± 0.31 562.6 ± 187.5 2040 7.42 ± 0.05 2.24 ± 0.11 202.1 ± 69.40 020 7.15 ± 0.13 0.80 ± 0.22 331.9 ± 16.50 MelonChinese cabbage double cropping 2040 7.06 ± 0.25 0.83 ± 0.18 67.90 ± 42.18 * EC e: Electrical conductivity of the saturation extract 참외연작비닐하우스의표토에서토양 EC e 는최고 6.0 ds/m까지조사되었으며, 노지콩재배포장의표토에비해평균값으로 4배정도높았다. 참외연작비닐하우스표토의평균 EC e 값은참외표준재배매뉴얼에서제시한적정 EC의상한값 2 ds/m를 2배이상초과하였다. 심토의 EC e 평균값은노지콩재배포장에서 1 ds/m 이하로조사되었고, 참외연작비닐하우스에서는 2 ds/m에근접한수준으로높게조사되었다. 이러한결과를보면, 비닐하우스환경에서다년간연작함으로써참외재배에적절한토양 EC 범위를훨씬초과하는수준으로토양에염류가집적된것이다. 유기물은참외연작비닐하우스의표토와심토에서평균함량이각각 2.83 및 1.44% 로노지콩재배포장에비해훨씬높았는데, 이는참외재배토양에는퇴비등유기물을지속적으로시용하기때문일것이다. 유효인산은참외연작비닐하우스포장표토에서평균 557.9 mg/kg이고최대 785.7 mg/kg까지측정되었는데, 노지콩재배포장의유효인산함량과비교하면거의 2배에해당된다. 참외에대한토양유효인산적정함량은 300500 mg/kg인데, 경북성주군과채류재배지토양의경우에유효인산함량이평균 413 mg/kg으로조사되어있다 ( 성주과채류시험장자료 ). 본연구에서조사한경산지역참외연작비닐하우스토양의유효인산함량은평균적으로적정치를초과하는수준이며, 인산을포함한시비량의조절이필요할것으로판단된다. 참외연작비닐하우스토양과노지콩재배토양의수용성이온함량은 Table 3과같았으며, EC와의관계를고려하여 cmole 단위로나타내었다. 조사대상이온들의함량은모두콩재배노지토양에비해참외연작비닐하우스토양에서높았으며, 비닐하우스토양에서는 Ca 2+ 과 SO 2 4 의함량이가장높았으며, Mg 2+, Cl, Na +, NO 3 등도노지토양에비해많 이집적된것으로나타났다. 시설재배지토양에집적되어작물에장해를유발하는염류는주로 Na +, K +, NH + 4, Ca 2+, Mg 2+ 등의양이온과 Cl, NO 3, SO 2 4, PO 3 4 등의음이온으로구성되어있으며, 조사대상비닐하우스에따라서다소차이는있으나 Ca 2+, Mg 2+, NO 3, SO 2 4, Cl 의함량이높고 EC와의상관관계도높은것으로밝혀져있다 (Yuk et al., 1993; Jung et al., 1994; Ha et al., 1997; Jung et al., 1998; Kim et al., 2006b). 대구근교상추재배비닐하우스토양에서는여러이온들중에서 NO 3 가가장높은농도로축적되어있다 (Chung et al., 2005). 해수의영향을받지않는노지환경의염류토양에서는가용성염류를구성하는이온이주로 Ca 2+, Mg 2+, SO 2 4 이며, K +, Na +, Cl, CO 2 3, HCO 3, NO 3 는소량포함되어있다 (Richards, 1954; Sparks, 1995). 이러한노지환경의염류토양과비교하면우리나라시 설재배지토양에서는 NO 3 형태의질소와인산의축적현상이뚜렷한데, 시설재배지토양의염류집적현상이상당부분화학비료와퇴비의과다시용에따른잔류양분의축적에기인함을의미하는것이다. 참외 배추및참외 미나리이모작에따른염류제거효과비닐하우스에서참외재배후천창비닐을제거한노지상태로배추를이모작으로재배한비닐하우스토양과참외를단작으로재배한비닐하우스토양특성을비교하였다 (Table 4). 참외재배후노지상태로배추를재배한경우참외단작비닐하우스토양에비해 ph는소폭낮아졌으며, 노지상태로배추를재배함으로써염류가제거되었기때문인것으로추정된다. 비닐하우스에서참외를재배한후천창을제거하고노지상태에서배추를재배한경우토양의 EC e 평균값은표토와심토에서모두 1 ds/m 이하로측정되었으며, 비닐하우스환

Desalinization Effect of Offseason Crop Cultivation 257 Table 5. Comparison of soil characteristics after season of oriental melon single cropping system and oriental melonwater dropwort double cropping system Cropping system Depth ph EC e* Available P cm ds/m mg P 2O 5/kg Melon single cropping 020 7.71 ± 0.16 3.26 ± 0.02 327.9 ± 102.0 2040 7.83 ± 0.10 1.88 ± 0.03 102.7 ± 31.20 020 7.63 ± 0.37 0.75 ± 0.29 216.3 ± 80.56 Melonwater dropwort double cropping 2040 7.77 ± 0.33 0.64 ± 0.27 163.1 ± 19.20 * EC e: Electrical conductivity of the saturation extract Table 6. Waterextractable ion contents in soils after season of oriental melon single cropping system and oriental melonchinese cabbage double cropping system Cropping system Depth K + Ca 2+ Mg 2+ Na + NH 4 + cm cmol/kg Melon single cropping 020 0.60 2.37 1.03 0.54 0.33 0.56 2.50 0.66 MelonChinese cabbage double cropping 020 0.14 0.25 0.39 0.34 0.25 0.16 0.22 0.31 NO 3 SO 4 2 Cl Table 7. Waterextractable ion contents in soils after season of oriental melon single cropping system and oriental melonwater dropwort double cropping system Cropping system Depth K + Ca 2+ Mg 2+ Na + NH 4 + cm cmol/kg Melon single cropping 020 0.54 2.40 0.88 0.39 0.29 0.74 1.53 0.97 Melonwater dropwort double cropping 020 0.11 0.52 0.19 0.32 0.26 0.32 0.30 0.40 NO 3 SO 4 2 Cl 경을계속유지한참외단작토양에비해 EC가현저히낮아졌다. 이러한결과를보면, 천창비닐을제거하고노지상태에서배추를재배함으로써참외재배기간동안축적된염류의상당부분이용탈과후작물의흡수에의해제거된것으로판단된다. 유효인산측정결과에서도노지상태에서배추를재배함으로써참외재배기간에토양에축적된유효인산의 50% 정도가제거되는것으로나타났다. 배추를재배한 9월부터 11 월사이의강수량은 200 mm 내외이었다 ( 대구및영천기상대자료 ). 참외재배후하우스시설을그대로유지한채토양전체를담수하고이모작으로미나리를재배한경우를보면 (Table 5), 참외단작비닐하우스토양에비해 ph의차이는없었으나표토와심토에서모두 EC e 는 1 ds/m 이하로현저히낮아졌고표토의유효인산함량역시미나리를후작물로재배한후크게낮아졌다. 미나리이모작비닐하우스에서심토의유효인산함량은참외단작비닐하우스토양에비해높게조사되었는데, 이는담수상태가 23개월지속되면서표토에서용탈된후심토에집적되었거나환원조건에서불용성인산화합물의가용화에따른결과로추정된다. 비닐하우스에서참외를재배한후천창을제거하고노지상태로배추를재배하거나하우스환경에서토양전체를담수하고미나리를재배한포장에서조사한토양의수용성이온함량변화는 Table 6 및 7과같았다. 천창비닐을제거하고배추를이모작으로재배한포장의경우, 참외단작후하우스 시설을그대로유지한포장에비해주요염류구성이온인 Ca 2+ 과 SO 2 4 가 90% 정도제거되었다. Na + 과 NH + 4 의제거율이상대적으로낮았지만나머지이온들도 4080% 범위에서제거되었다. 참외재배후미나리를재배한포장의경우에도참외단작하우스토양과비교하여 Ca 2+, Mg 2+, K + 2, SO 4 가 80% 정도제거되었으며, 배추를후작물로재배한경우와마찬가지로 Na + 과 NH + 4 의제거율은낮았다. 참외재배후천창을제거하고배추를재배한경우와하우스시설을유지한채로담수상태로미나리를재배한경우를비교하면, 작물의흡수와용탈에따른염류구성주요이온들의제거효율은거의동일하였다. 그리고각각의이모작체계에서주요가용성염류의제거효율과 EC 저감효과는각각 8090% 로서로잘일치하였다. 비닐하우스의천창을개방하고녹비작물을재배하였을때토양의 EC는 4 ds/m에서 2 ds/m 이하로낮아졌으며 ( 시설원예연구소미발표자료 ), 담수처리한토마토재배비닐하우스에서표토의 EC가 2.80 ds/m에서 0.38 ds/m로낮아지는것으로보고되어있다 (Oh et al., 2010). 그리고담수처리에따른염류제거율은토성에따라서차이가있지만 1 회에 100 mm씩 2회처리하였을때표토의염류를 4055% 제거할수있는것으로밝혀져있다 (Jung and Yoo, 1975). 이러한여러선행연구들의결과와본연구의결과를보면, 염류집적비닐하우스토양을자연강우에노출시키거나담수처리를하고이모작작물을재배함으로써다음작기주작물에

258 Byeon et al. Table 8. Changes in electrical conductivity of soil during the oriental melon growing season with oriental melonchinese cabbage double cropping system and oriental melonwater dropwort double cropping system Cropping system Before melon cropping April May June July ds/m MelonChinese cabbage double cropping 0.80 ± 0.22 2.15 ± 0.58 3.16 ± 1.31 2.97 ± 1.43 2.89 ± 0.22 Melonwater dropwort double cropping 0.75 ± 0.29 1.78 ± 0.77 1.91 ± 0.83 2.28 ± 1.41 2.63 ± 1.95 염류장해를유발하지않는수준까지염류를제거할수있는것으로판단된다. 그리고투수성이불량하거나작토층아래에경반층이존재하는토양에서는용출된염류를하우스외부로배출시킬수있는암거배수시설등을갖추면자연강우나관수또는담수처리를통한염류제거효율을더욱증대시킬수있을것이다 (Kim et al., 1997; Oh et al., 2010; Kim et al., 2006a) 이모작후참외재배기간중토양 EC의변화참외 배추및참외 미나리이모작하우스에서다음작기의참외를재배하는동안토양 EC 변화를 4월부터 7월까지 4회조사한결과는 Table 8과같았다. 배추를이모작한하우스에서는노지상태로배추를재배한후 0.80 ds/m 수준으로낮아졌던 EC가다음작기참외를재배하면서 4월에염류장해기준인 2 ds/m를상회하였고 5 월부터 7월까지 3 ds/m 내외로유지되었다. 참외 미나리이모작하우스에서도마찬가지로미나리재배후 0.75 ds/m 수준으로낮아졌던 EC가참외를재배하면서 4월에 1.78 ds/m로증가하였고이후계속증가하여 2 ds/m를훨씬상회하는수준으로조사되었다. 이러한결과를보면, 비닐하우스에서참외를재배한후후작물로노지배추나담수미나리재배를도입하더라도단기적으로이전참외재배기간에축적된염류를 EC 1 ds/m 이하수준으로제거할수있었지만다음작기참외를재배하는동안이모작재배이전과비슷한수준으로염류농도가다시높아지는것으로나타났다. 이는화학비료와퇴비를기비로과다시용하고재배기간동안관행적으로수용성비료를관주시스템을통해수시로공급하는데기인할수있으며 (Ha et al., 1997), 또한이모작기간에자연강우노출이나담수처리를통해하층토양으로용탈되었던염류들이참외재배기간에다시표층토양으로상승하기때문일것이다 (Kim et al., 1997; Oh et al., 2010). 따라서토양검정을통한적정시비와함께매년지속적으로노지배추재배와담수미나리재배등의이모작체계를도입함으로써비닐하우스장기연작토양의과다한염류집적문제를해소할수있을것으로판단된다. 결론 비닐하우스에서작물을재배할경우토양에염류가집적되는현상은피할수없는데, 경비나부지의문제로하우스시설의이전이어려운실정에서는다양한방법을통해장기연작에따른염류집적문제를해결해야한다. 비닐하우스참외재배농가에서활용하고있는참외 노지배추또는참외 담수미나리이모작체계는자연강우나담수를통해참외재배기간에집적된하우스토양의염류를후작물을재배하는동안 EC e 1 ds/m 이하로제거할수있었으며, 다음작기참외를재배하는동안 EC e 는 23 ds/m 수준으로유지되어과다한염류집적에따른피해를방지할수있었다. 그러나이러한이모작체계의염류제거효과는다년간지속될수없는것으로추정되었으며, 참외재배기간에집적된염류를매년제거하도록이모작작부체계를지속적으로유지하는것이바람직한염류장해해결수단으로판단된다. 자연강우나담수를통해표층토양에서용탈된염류가하층토양에집적되었다가다음작기참외재배기간에다시표층으로상승하는염류재집적현상을해결하기위해서는염류를하우스외부로배출시킬수있는암거배수시설을도입하는방안도적극적으로고려해야한다. 물론비닐하우스토양에집적된염류를제거하는노력에앞서토양검정에의한적정수준의시비관리와관개용수의관리를통해과도한염류의유입을사전에차단하는노력이먼저필요할것이다. Acknowledgment This research was supported by the Daegu University Research Fund in 2013. References Cho, M. R., Lee, B. C., Kim, D. S., Jeon, H. Y., Yiem M. S., & Lee, J. O. (2000). Distribution of plantparasitic nematodes in fruit vegetable production areas in Korea and identification of rootknot nematodes by enzyme phenotypes. Korean Journal of Applied Entomology, 39(2), 123129. Chung, J. B., Jin, S. J., & Cho, H. J. (2005). Low water potential in saline soils enhances nitrate accumulation of lettuce. Communications in Soil Science and Plant Analysis, 36(1314), 17731785. Chung, B. Y., Lee, K. S., Kim, M. K., Choi, Y. H., Kim, M. K., & Cho, J. Y. (2008). Salt accumulation and desalinization of rainfall interception culture soils of Rubus sp. in Gochanggun, Jeollabukdo. Korean Journal of Soil Science and Fertilizer, 41(5), 310317.

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