Korean Journal of Environmental Agriculture Korean J Environ Agric. 2014;33(1):9-16. Korean Online ISSN: 2233-4173 Published online 2014 February 24. http://dx.doi.org/10.5338/kjea.2014.33.1.9 Print ISSN: 1225-3537 Research Article Open Access 녹비작물의파종시기와방법이무농약배과원의시기별토양화학성과엽내무기성분, 과실품질에미치는영향 임경호, 1,2 최진호, 1 김월수, 3 김현지, 2 송장훈, 1 조영식, 1 임순희, 1 정석규, 4 최현석 4* 1 국립원예특작과학원배시험장, 2 전남농업기술원친환경연구소, 3 전남대학교원예학과, 4 대구가톨릭대학교화훼원예학과 Seasonal Soil and Foliar Nutrient Concentrations, and Fruit Quality in a Pesticide- Free Pear Orchard as Affected by Seeding Timing and Method of Cover Crops Kyeong-Ho Lim, 1,2 Jin-Ho Choi, 1 Wol-Soo Kim, 3 Hyun-Ji Kim, 2 Jang-Hoon Song, 1 Young-Sik Cho, 1 Sun-Hee Yim, 1 Seok-Kyu Jung 4 and Hyun-Sug Choi 4* ( 1 Pear Research Station, National Institute of Horticultural & Herbal Science, Naju, Jeollanam-do 520-821, Korea, 2 Environmentally-Friendly Research Center, Jeollanam-do Agricultural Research & Extension Services, Naju, Jeollanam-do 520-715, Korea, 3 Department of Horticulture, Chonnam National University, Gwangju 500-070, Korea, 4 Department of Floriculture, Catholic University of Daegu, Gyeongsan, Gyeongsangbuk-do 712-702, Korea) Received: 31 October 2013 / Revised: 5 February 2014 / Accepted: 24 February 2014 Copyright c 2014 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract BACKGROUND: This study was conducted to investigate the effects of seeding timing and method of rye and/or hairy vetch on seasonal soil and foliar nutrient concentrations as well as fruit quality in a pesticide-free pear orchard. METHODS AND RESULTS: The treatments included as followed: single seeding of rye in September (Sep-Mono), November (Nov-Mono), and January (Jan-Mono), or mix seeding of rye+hairy vetch in November (Nov-Mix) and January (Jan-Mix), or sod culture as a control. Cover crops or vegetation was mown and mulched on the soil surface in April and May for two years. Nov-Mix treatment produced the highest dry matter weight of 12,070 kg ha -1, with the lowest dry matter weight for sod culture (6,520 kg ha -1 ), following Jan-Mix (7,030 kg ha -1 ). Nov-Mix treatments increased potential amount of N, P, and K from the raw * 교신저자 (Corresponding author): Hyun-Sug Choi Phone: +82-53-850-3279; Fax: +82-53-850-3279; E-mail: hchoiuark@gmail.com materials of the cover crops as well as improved soil physical properties. Nov-Mix treatments overall elevated soil ph, EC, organic matter, and P 2 O 5 in May compared to other cover crop treatments or sod culture. The difference of the seasonal nutrient concentrations in leaves or fruit qualities were not consistently occurred amongst treatments. CONCLUSION: Nov-Mix treatments showed playing role in a substitute of a chemical fertilizer. Delayed seeding of cover crops such as Jan-Mix did not increase the potential dry matter production due to the short growing period, and the seeding time would affect the dry matter production of cover crops. Key words: Cover crop, Fruit quality, Nutrient, Pear, Soil 서론 무농약인증기준의배과수원의허용시비량은일반관행농의시비량대비 30% 수준인질소 6.66 kg - 인산 4.33 kg - 가리 5.99 kg/10 a으로시비량이절대부족한현실이다 9
10 LIM et al. (Environmentally-Friendly Agriculture Research Center, 2010). 유기농업에서작물생장을위해요구되는질소공급은두과작물재배에의한질소고정이나녹비작물잔사에함유된유기물의분해로공급되는무기태질소또는추가적인유기질비료의시용으로가능하다 (Fageria et al., 2005; Barker, 2010). 하지만녹비작물의탄질율 ( 탄소 : 질소율 ) 에따라분해율이달라지는데, 탄질율이낮은헤어리베치는질소무기화율 (N-mineralization) 이높아서분해후단기간에토양에많은양의무기태질소를공급하고반대로화본과작물은탄질율이높아서소량의무기태질소를공급한다 (Rosecrance et al., 2000; Fageria et al., 2005; Sainju et al., 2005; RDA, 2009; Barker, 2010; Lawson et al., 2013). 질소고정이뛰어난헤어리베치의생육이왕성하면휴경기인겨울과봄철에질산태질소의용탈로토양수를오염시킬수있으므로, 흡비력이좋은화본과인호밀을혼파하면질소과잉을감소시키고본작물 (cash crop) 의무기태질소공급에도효과적일수있다 (Rosecrance, 2000). 호밀은토양의유기물함량을증가시키고물리성개선에도효과적이므로국내에서도가을녹비작물로많이이용되고있다. 영년생인배나무는재배기간초기 ( 봄철 ) 에는저장양분이있는수피로부터양분을이용하여영양생장을하고, 개화 30일후에는주로토양으로부터흡수되는물이나양분을이용하여영양생장과생식생장을지속시킨다 (Weinbaum, 2007). 배나무가토양으로부터양분공급이필요한시기인 5월이나 6월에겨울녹비작물이분해가빠르게진행된다면영양생장을위한수요와공급측면에서효과적이다고할수있겠다. 호밀과헤어리베치를이용하여배과원에시기별 (9 12월) 로단파하였을때또는동일시기 (10월중순 ) 에두초종을단파나혼파하였을때환원되는양분량도달라졌다 (Lim et al., 2011; Lim et al., 2012). 따라서이러한두초종을이용하여시기별로단파나혼파처리하였을때토양중무기성분량이나토양물리성또는배나무생장과과실품질에도영향을미칠것으로판단되나이에대한연구는미비한실정이다. 전남지역의배친환경인증농가수는증가추세에있으나대부분이저농약인증단계에머물러있다. 무농약이나유기재배배과수원도점차증가하고는있지만여전히무농약재배에알맞은시비관리체계와화학비료대체기술이정립되어있지않은실정이다. 따라서본연구는무농약재배배과수원에서화학비료대체를위한최적의녹비작물의파종시기와방법을규명하기위하여실시하였다. 재료및방법 시험재료및처리방법본시험은전남영암군덕진면금강리 ( 위도 ; 34.8, 경도 ; 126.7 ) 에위치한개인농가에서수행하였다. 시험수행기간인 2006, 2007, 2008년에영암인근지역의재배기간동안 (5 10월 ) 평년온도는각각 21.9 C, 22.1 C, 22.7 C (KMA, 2006 2008) 이었다 (30년간평균온도 ; 21.7 C). 강수량은 2006, 2007, 2008년에각각 1,270 mm, 1,326 mm, 795 mm(30년간평균강수량 ; 1,082 mm) 으로강수량이시험첫 2년동안은평년보다많은것으로관찰되었다. 시험재료는배 신고 품종 9년생을이용하였으며시비량은무농약재배배과수원허용시비량 (Environmental- Friendly Agriculture Research Center, 2010) 에준하여질소- 인산- 칼리를 10 a당각각 6.7-4.3-6.0 kg의화학비료를시비하였다. 대조구인방임초생구는허용시비량에서부족한량을유기질비료 ( 유박 ) 를이용하여질소량 13.3 kg/10 a에맞추어서추가로시비하였고, 녹비작물처리구는부족한시비량을추가시비없이녹비작물을재배하여과수원에환원하여주었다. 시험처리에이용된녹비작물인호밀과헤어리베치의품종은각각 단코 와 마베초 를이용하였다. 호밀과헤어리베치파종시기와방법에대한시험으로파종시기는 2006년부터 2007년까지 2년동안 9월하순, 10월중순, 11월중순, 1월하순에파종하였다. 파종방법은호밀단파는 16 kg/10 a을, 호밀과헤어리베치혼파는호밀 6.4 kg/10 a + 헤어리베치 3.0 kg/10 a로파종하여이듬해 4월과 5월에두차례예초하였다. 각각의처리내용에대한요약은다음과같다. 호밀 9 월하순파종 (9월단파 ), 호밀 11월중순파종 (11월단파 ), 호밀 1월하순파종 (1월단파 ), 호밀 + 헤어리베치 11월중순파종 (11월혼파 ), 호밀 + 헤어리베치 1월하순파종 (1월혼파 ), 방임초생 ( 대조구 ) 으로구성하였다. 녹비작물은예초후잔사를토양안에환원시키지않고지표면위에그대로두어서자연고사시켰다. 2년간처리에따른시험조사및분석은 3년차인 2008년에수행하였다. 조사항목녹비작물의생육조사는초장은지면으로부터최장엽선단까지의길이를조사하고줄기수는 2엽이상출현된것을측정하였다. 이후수관주위 1 m 2 에서예초한녹비를수확하여 3일간 70 80 C의건조기에넣은후건물중을측정하고마쇄시켜 40mesh 체로거른후에무기성분함량측정용시료로사용하였다. 식물체분해는습식분해법 (RDA, 2000) 으로하였는데전질소는 Kjeldahl 법으로인은 Vanadate 법으로, 칼륨은 ternary용액 (HNO 3: H 2SO 4: HClO 4, 10:1:4, v/v/v) 으로가열분해하여원자흡광도 (ICP-AES, PU 9000, Pye-Unicam Ltd., Cambridge, England) 로측정한성분에녹비작물의건물중을곱하여양분환원량으로환산하였다. 배과원의 0 30 cm 깊이의토양을 4월 19일, 5월 31일, 7월 18일, 8월 3일에채취하였고, 시험토양의화학성은농촌진흥청의토양및식물체분석법 (RDA, 2000) 에따라토양 ph는초자전극으로, 유기물함량은 Walkely-Black 법, 유효인산은 Lancaster법, 치환성양이온인가리는초산암모늄추출법으로측정하였다. 토양물리성은 8월초에 core ( 용량 100 ml) 를이용하여주간에서 1.5 m 떨어진위치에서 10 cm 깊이로시료를채취하여, 토양과 core의전중량과 105 C 건조기에서건조한무게를평량한건토중량법으로용적밀도와
Soil and Foliar Nutrients, and Fruit Quality in a Pear Orchard Affected by Seeding Timing and Method of Cover Crops 11 공극률을환산하였다 (RDA, 2000). 배나무엽의질소와인, 칼륨농도는 5월 30일, 7월 6일, 그리고 8월 16일에신초의중간위치에있는엽을주당 50매정도를임의로채취하여위에서언급한녹비작물의무기성분분석방법으로측정하였다. 10월초에배과실을수확하여전자저울로과중을조사한후, 과실중간면의과피를제거하여착즙한과즙으로굴절당도계 (Refractrometer, Atago, Japan) 로당도를확인하였고, 과실경도계 (TA-XT2, Texture technologies Corp., Scarsdale, NY, USA) 로경도를조사하였다. 과피색은색차계 (Minolta CR-300, Japan) 로 Hunter value L *, a *, b * 값으로표시하였다. L * 은과피의밝기를, a * 와 b * 는각각과피의적색과황색의정도를나타내었으며, 값이클수록각값의과피색이진함을의미하였다. 통계분석배과수원의경사지중간지점에위치한배나무를무작위로선정하여 1주 1반복으로완전임의배치법 5반복으로처리하였다. 시기별무기성분분석은표준오차를이용하였고, 그이외의통계분석은 SAS 프로그램 (SAS version 8/2, NC, USA) 을이용하여처리평균간의유의성검증인 95% 신뢰수준으로 Duncan s multiple range test로분석하였다. 결과및고찰 11월단파처리 (Nov-Mono; 11월호밀파종 ) 가 4월 (1차예초 ) 과 5월 (2차예초 ) 에초장이길고줄기수가많았고, 생엽수는 11월혼파 (Nov-Mix; 11월호밀 +11월헤어리베치파종 ) 이가장많았다 (Table 1). 1월혼파 (Jan-Mix; 1월호밀 +1월헤어리베치파종 ) 는초장이짧고줄기수가적었다. 건물중은방임초생재배 (Sod) 652 kg/10 a 대비 11월혼파 1,207 kg, 11월단파 1,053 kg, 9월단파 (Sep-Mono; 9월호밀파종 ) 는 994 kg, 1월단파 (Jan-Mono; 1월호밀파종 ) 849 kg 순으로높았다 (Table 2). 1월혼파는 703 kg으로녹비작물처리구중건물중이가장낮아호밀과헤어리베치의생육특성상저온 에비교적강하긴하지만파종적기와관련이있는것으로판단된다. 전남보성지역의배과원에서는 9월과 10월의혼파가 11월혼파처리보다높은건물중을보였는데 (Lim et al., 2011), 이는장기간녹비작물의재배나파종당시강수량과지형에따른차이일것이라고언급하였다. 본시험에서는 9, 11, 1월호밀단파처리에서자연초종발생량은 1월단파에서 4배이상많았는데, 호밀의늦은파종으로초종발생량이우점한것에따른결과로생각된다. 초종별전질소농도는두과작물인헤어리베치가 3.8% 로가장높았고호밀은 1.7 2.3%, 자연초종도 1.6 2.4% 수준으로나타나서 (Table 3), 기존에제시된두녹비작물의일반적인농도수준과비슷하였다 (Environmental-Friendly Agriculture Research Center, 2010). 녹비작물의잠재적인전질소환원량은 11월혼파가 33.3 kg/10 a로가장많았으며 1월단파 (17.8 kg/10 a), 9월단파또는 1월혼파 (17.6 kg/10 a), 11월단파 (17.3 kg/10 a), 방임초생 (14.2 kg/10 a) 순으로높았다 (Table 4). 성목의배나무는당년의영양생장을하기위해서 20 kg/10 a 전후의질소량을요구하는데 (Environmental-Friendly Agriculture Research Center, 2010), 온대성기후의일반과원에서식물잔재는 3개월동안약 60 70% 만이분해되었다 (Tutua et al., 2002; Tagliavini et al., 2007) 고하여서 30 35 kg/10 a 전후의질소량이녹비작물로부터필요할것으로판단된다. 따라서 11월혼파를제외하고는모든처리구에서질소요구량을충족시키지못한것으로여겨져서 4월과 5월에 2회예초하여이용시에는화학비료대체가불가능할것으로판단되었다. 녹비의질소환원량은 11월혼파를제외하고는녹비건물중과비례하지는않았는데, 이는두초종의질소농도가달라서영향을크게받지는않았던것으로분석된다. 녹비작물의잠재적인인환원량은 11월혼파 (9.0 kg/10 a) > 1월단파 (6.2 kg/10 a) > 1월혼파 (6.0 kg/10 a) > 방임초생 (5.9 kg/10 a) > 11월단파 (3.5 kg/10 a) > 9월단파 (2.7 kg/10 a) 순으로나타났다 (Table 4). 호밀의경우일반자연초종보다인농도가낮아서건물중이높더라도환원되는총 Table 1. Cover crop growth at a Niitaka pear orchard as affected by seeding time and method Treatment Cover crop growth Height (cm) Leaf (No/plant) Stem (No/m 2 ) Seeding Cover crop Apr. May Apr. May Apr. May Sep-Mono Rye 97 c 84 bc 6.7 b 4.5 c 804 b 319 b Nov-Mono Rye 131 a 99 a 6.3 bc 4.5 c 1,044 a 963 a Jan-Mono Rye l74 e 91 ab 5.6 cd 4.4 c 363 c 337 b Nov-Mix Rye 118 b 92 ab 6.2 bc 4.3 c 737 b 904 a Vetch 85 d 61 d 11.2 a 9.0 a 193 d 81 d Rye 58 f 75 c 5.3 d 4.4 c 137 de 193 c Jan-Mix Vetch 0 g 48 e 0.0 e 7.1 b 0 e 41 d Sep-, Nov-, or Jan-Mono are referred as rye seeding in Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Means separation within columns by Duncan s multiple range test at P < 0.05.
12 LIM et al. Table 2. Cover crop dry weight at a Niitaka pear orchard as affected by seeding time and method Treatment Cover crop dry wt. (kg/10 a) Seeding Cut time Rye Vetch Vegetation Total Sep-Mono Nov-Mono Jan-Mono Nov-Mix Jan-Mix Apr. 701 0 0 701 May 170 0 123 293 Apr+May 871 a 0 c 123 e 994 b Apr. 783 0 0 783 May 160 0 110 270 Apr+May 943 a 0 c 110 e 1,053 b Apr. 214 0 330 544 May 107 0 198 305 Apr+May 321 c 0 c 528 b 849 c Apr. 470 254 110 834 May 174 66 133 373 Apr+May 644 b 320 a 243 d 1,207 a Apr. 132 0 245 377 May 87 61 178 326 Apr+May 219 d 61 b 423 c 703 d Apr. 0 0 454 454 Sod May 0 0 198 198 Apr+May 0 e 0 c 652 a 652 d Sep-, Nov-, or Jan-Mono are referred as rye seeding in Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Sod is referred as a sod culture. Means separation within columns by Duncan s multiple range test at P < 0.05. Table 3. Nutrient concentration of cover crop at a Niitaka pear orchard as affected by seeding time and method Treatment Sep-Mono Nov-Mono Jan-Mono Nov-Mix Crop Nutrient concentration (%) T-N P K T-N P K April May Rye 1.9 0.2 3.0 1.6 0.5 2.0 Vege. - - - 1.6 0.5 2.3 Rye 1.7 0.3 2.1 1.5 0.5 2.1 Vege. - - - 1.6 0.4 3.2 Rye 2.3 0.8 2.0 1.8 0.5 2.3 Vege. 2.4 1.0 2.8 1.6 0.4 2.9 Rye 2.1 0.8 2.1 1.8 0.5 2.4 Vetch 4.8 0.9 3.5 3.0 0.4 2.8 Vege. 3.2 1.1 3.7 1.9 0.5 3.2 Rye 2.6 0.8 1.7 2.1 0.5 2.6 Jan-Mix Vetch - - - 3.2 0.4 0.9 Vege. 2.8 1.0 3.0 2.0 1.0 3.4 Sod Vege. 2.4 0.9 2.4 1.7 1.0 4.0 Sep-, Nov-, or Jan-Mono are referred as rye seeding in Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Sod is referred as a sod culture. 인은 11월혼파를제외하고는오히려비슷하거나낮았다. 매해성목의배나무가요구하는인은 13 kg/10 a (Environmentally- Friendly Agriculture Research Center, 2010) 로모든처리구에서기준량보다낮아서추가적인인산시비가필요하였다. 보성지역에서의헤어리베치와호밀의단파혹은혼파처리시험에서도인은시기에상관없이약 5 kg/10 a 전후의환원량을나타내어서 (Lim et al., 2011; Lim et al., 2012), 연령별배나무의인산추가량을달리해서공급해야할것으로판단된다. 칼륨환원량은 11월혼파처리가 33.1 kg/10 a로가장높았다 (Table 4). 그다음으로 9월단파 (27.4 kg/10 a) > 11월단파 (23.2 kg/10 a) > 1월단파 (21.6 kg/10 a) > 방임초생 (18.9 kg/10 a) > 1월혼파 (18.6 kg/10 a) 순으로호밀의건물중이높을수록칼륨환원량이높아서호밀의칼륨농도가어느정도영향을끼쳤을것으로풀이된다 (Table 3). 배나무가생장을위해요구되는가리량은 18 kg/10 a(environmentally- Friendly Agriculture Research Center, 2010) 으로녹비작물분해량으로환산하면약 30 35 kg/10 a의칼륨이필요하는데 (Tagliavini et al., 2007; Tutua et al., 2002), 11월혼파를제외하고는모든처리구에서기준이하여서추가적인가리를시용하여야할것으로판단된다. 토양 0 10 cm 깊이의토양용적밀도와고상은방임초생이가장높았고, 1월단파또는 1월혼파처리도높은수준이
Soil and Foliar Nutrients, and Fruit Quality in a Pear Orchard Affected by Seeding Timing and Method of Cover Crops 13 Table 4. Estimated Total Nitrogen, P, and K production at a Niitaka pear orchard as affected by seeding time and method Seeding Sep-Mono Nov-Mono Jan-Mono Nov-Mix Jan-Mix Treatment Estimated nutrient production (kg/10 a) Cut time T-N P K Rye Vetch Vege. Total Rye Vetch Vege. Total Rye Vetch Vege. Total Apr. 13.0 0.0 0.0 13.0 1.1 0.0 0.0 1.1 21.1 0.0 0.0 21.1 May 2.7 0.0 1.9 4.6 0.9 0.0 0.6 1.5 3.4 0.0 2.9 6.3 Apr+May 15.7 a 0.0 c 1.9 d 17.6 b 2.0 c 0.0 b 0.7 d 2.7 d 24.5 a 0.0 b 2.9 d 27.4 b Apr. 13.2 0.0 0.0 13.2 2.3 0.0 0.0 2.3 16.3 0.0 0.0 16.3 May 2.4 0.0 1.7 4.1 0.7 0.0 0.5 1.2 3.4 0.0 3.5 6.9 Apr+May 15.6 a 0.0 c 1.7 d 17.3 b 3.0 b 0.0 b 0.5 d 3.5 c 19.8 b 0.0 b 3.5 d 23.2 c Apr. 4.9 0.0 7.9 12.8 1.8 0.0 3.2 5.0 4.2 0.0 9.2 13.4 May 1.9 0.0 3.1 5.0 0.5 0.0 0.7 1.2 2.5 0.0 5.7 8.2 Apr+May 6.8 c 0.0 c 11.0 b 17.8 b 2.3 c 0.0 b 3.9 b 6.2 b 6.7 d 0.0 b 14.9 b 21.6 cd Apr. 10.0 12.1 3.5 25.6 3.6 2.3 1.2 7.1 9.9 8.9 4.1 22.9 May 3.2 1.9 2.6 7.7 0.9 0.3 0.7 1.9 4.2 1.8 4.2 10.2 Apr+May 13.2 b 14.0 a 6.1 c 33.3 a 4.5 a 2.6 a 1.9 c 9.0 a 14.1 c 10.7 a 8.3 c 33.1 a Apr. 3.4 0 6.8 10.2 1.0 0.0 2.5 2.6 2.3 0.0 7.4 9.7 May 1.9 1.9 3.6 7.4 0.4 0.2 1.8 2.4 2.3 0.6 6.0 8.9 Apr+May 5.3 c 1.9 b 10.4 b 17.6 b 1.5 d 0.2 b 4.3 b 6.0 b 4.6 d 0.6 b 13.4 b 18.6 d Apr. 0.0 0.0 10.8 10.8 0.0 0.0 3.9 3.9 0.0 0.0 11.0 11.0 Sod May 0.0 0.0 3.4 3.4 0.0 0.0 2.0 2.0 0.0 0.0 7.9 7.8 Apr+May 0.0 d 0.0 c 14.2 a 14.2 c 0.0 e 0.0 b 5.9 a 5.9 b 0.0 e 0.0 b 18.9 a 18.9 d Sep-, Nov-, or Jan-Mono are referred as rye seeding in Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Sod is referred as a sod culture. Means separation within columns by Duncan s multiple range test at P < 0.05. T-N, Total Nitrogen Table 5. Soil bulk density, particle size, and porosity at a 0-30 cm depth at a Niitaka pear orchard as affected by seeding time and method Treatment Bulk density Particle size (%) (Mg/m 3 ) Solid Liquid Air Porosity (%) Sep-Mono 1.39 bc 52.5 bc 31.5 a 16.0 a 47.5 ab Nov-Mono 1.39 bc 52.4 bc 28.9 a 18.8 a 47.6 ab Jan-Mono 1.44 abc 54.4 abc 26.7 a 18.9 a 45.6 abc Nov-Mix 1.38 c 52.1 c 29.3 a 18.6 a 47.9 a Jan-Mix 1.46 ab 55.1 ab 26.2 a 18.7 a 44.9 bc Sod culture 1.47 a 55.6 a 30.2 a 14.3 a 44.4 c Sep-, Nov-, or Jan-Mono are referred as rye seeding in Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Means separation within columns by Duncan s multiple range test at P < 0.05. 었다 (Table 5). 녹비작물처리방법에상관없이빠른시기의녹비작물처리 (9월또는 11월파종 ) 는토양내부에뿌리잔사량을축적시켜 (Table 2) 토양의용적밀도감소와공극률증가로이어져서토양물리성개선에효과적인것으로관찰되었다 (Fageria et al., 2005). 토양샘플은 0 10 cm 깊이에서취 하였기때문에녹비작물의처리방법에따른토양물리성효과는뚜렷하게나타나지않았는데, 이후연구에서는배나무뿌리가 70% 이상잔존하는 (Faust, 1989) 0 90 cm의심토에서도조사가이루어져야할것으로판단된다. 토양 0 30 cm 깊이에서 ph는관찰시기 (4, 5, 7, 8월 ) 에
14 LIM et al. 상관없이방임초생보다녹비작물처리구에서높았는데 1월혼파는녹비작물처리간비교에서다소낮은수준을보였다 (Fig. 1). 토양 ph는모든시험구에서 6.0 7.5 사이의중성으로배나무가생장하기에좋은토양이화학성을나타내었다 (Reil, 2007). 4월과 5월에예초된녹비작물은지표면에서분해되어질소의무기화작용 ( 질산화작용 ) 이촉진되면서 (Koehn et al., 2002) 7월과 8월의토양 ph를낮추는데부분적으로영향을미쳤을것으로판단된다. 또한예초후녹비작물의환원은토양 EC (Electrical conductivity, EC) 를급격히증가시켰으며, 특히 9월단파와 11월단 혼파는 1.0 1.5 ds/m의높은수준을보여주었다 (Fig. 1). 토양용액중에용해되어있는염을나타내는 EC가높으면무기성분농도가상대적으로높음을추정할수있으며, 일반적으로 1.0 ds/m 이상의 EC는과수생장과수량을감소시켰다는보고가있었다 (Mass, 1993). 본시험에서토양 EC가높았던 9월단파와 11월단 혼파는 7월과 8월조사에서모든처리에서 0.5 ds/m 이하를나타내어수체생장을위한장기간의염류장 해는없었을것으로판단되었다. 토양유기물은녹비작물의건물중함량이가장높았던 11 월단 혼파의 5월조사에서 4.2% 로가장높았고, 방임초생과 1월혼파가각각 2.3, 2.2% 로가장낮았다 (Fig. 2). 그외의관찰시기에는방임초생을포함한처리간에비슷한유기물수준인 2 3% 를나타내어무농약배과수원도기존의관행과원에서요구하는유기물적정수준을보여주었다. 토양인산과가리도 5월예초후에조사한시기에모든처리구에서방임초생보다높았으며, 11월단파또는혼파에서가장높았다 (Fig. 2). 7, 8월의토양중인산과가리농도는처리간에경향이나타나지않았다. 11월혼파처리는칼륨환원량이가장높았지만 (Table 4) 토양중가리농도가다른처리구와비교하여시기에상관없이비슷하거나낮은수준을보였다. 가리는토양에서이동성이높은원소로알려져서 (Fasut, 1989) 환원량수준과별다른상관관계를보이지않는것으로판단되었다. 또한토양중마그네슘이나칼슘과같은다른양이온농도가상대적으로높아서경쟁작용에의해용탈되었을가 Sep-, Nov-, or Jan-Mono are referred as rye seeding in Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Means separation within columns by Duncan s multiple range test at P < 0.05. Fig. 1. Soil ph and electrical conductivity at a 0-30 cm depth at a Niitaka pear orchard as affected by seeding time and method. Sep-, Nov-, or Jan-Mono are referred as rye seeding in Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Means separation within columns by Duncan s multiple range test at P < 0.05. Fig. 2. Soil organic matter, P 2O 5, and K 2O at a 0-30 cm depth at a Niitaka pear orchard as affected by seeding time and method.
Soil and Foliar Nutrients, and Fruit Quality in a Pear Orchard Affected by Seeding Timing and Method of Cover Crops 15 능성도추정된다. 배나무엽내질소와칼륨농도는 5월조사에서 11월단 혼파에서방임초생보다높았으나, 7월과 8월의엽중질소와칼륨그리고인농도는녹비작물처리구와방임초생이비슷하였다 (Fig. 3). 이는조사된배나무가성목이어서처리구간에비슷한엽농도를보였을것으로판단되며, 전체적인양분함량을나타내는엽함량 ( 엽농도 * 엽중 ) 조사가추가적으로필요할것으로판단된다. 엽중질소와인그리고칼륨농도는 7 월에서 8월에처리에관계없이감소하였는데, 이는위의세가지무기성분이대사작용이왕성한어린엽부위로이동하였기때문에시기적으로농도가감소 (Faust, 1989; Westwood, 1993) 한것으로판단되었다. 유기재배한사과나무의엽내질소와인그리고칼륨농도가시기적으로감소하였다는이전보고와일치하였다 (Nagy and Holb, 2006; Choi et al., 2011). 배과실특성조사에서는대체적으로처리간에일관성있는결과를보이지는않았다 (Table 6). 9월단파와 11월단 혼파에서 800 g 이상의평균과중을보였고방임초생과 1월 단 혼파는 770 g 전후를나타내었지만, 처리간에통계적으로유의성있는결과는나타나지않았다. 과실당도는 9월단파에서 12.3 Bx로높았고 11월단파가 11.2 Bx로가장낮았다. 과실경도와과형은처리간에별다른차이가나타나지않았다 (P > 0.05). 과피의밝기와푸른색을나타내는착색도도처리간에차이가없었으며 (P > 0.05), 과피의적색도는방임초생과 11월단파처리에서가장낮은색도를보였다. Table 6. Fruit characteristics at a Niitaka pear orchard as affected by seeding time and method Treatment Weight SSC Firmness Hunter value Shape (g) ( Bx) (N) L * a * b * Sod culture 769 a 11.8 b 2.56 a 1.21 a 63.8 a 4.59 ab 34.9 a Sep-Mono 868 a 12.3 a 2.62 a 1.16 a 65.1 a 5.22 a 36.1 a Nov-Mono 813 a 11.2 c 2.84 a 1.15 a 64.9 a 4.18 b 34.9 a Jan-Mono 772 a 11.7 bc 2.62 a 1.17 a 65.1 a 5.06 a 35.4 a Nov-Mix 801 a 12.1 ab 2.77 a 1.17 a 64.0 a 5.15 a 35.8 a Jan-Mix 771 a 11.6 bc 2.79 a 1.22 a 64.2 a 5.35 a 36.4 a Sep-, Nov-, or Jan-Mono are referred as rye seeding in September, November, or January. Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Means separation within columns by Duncan s multiple range test at P < 0.05. 본시험에서는이전에보고된이른시기 (9월) 의호밀또는헤어리베치의단파처리는양분환원량을증가시켰다는결과 (Lim et al., 2011) 와다소다르게나타나서기후와같은환경적인요인이나파종방법이녹비작물생육과양분공급량에어느정도영향을미치는것으로판단되었다. 11월혼파처리는다량의녹비작물건물중을생산하여부족한비료량을추가시용한방임초생구와같이질소와인그리고칼륨의잠재적인공급량을증가시켜서전반적으로토양의화학성과물리성을개선하였다. 이는화학비료를 30% 만사용하는무농약인증과원에서적절한녹비작물재배시기와파종방법은건전한배나무로생육하는데충분히가능하다는것을보여주는것으로풀이된다. 늦은시기의호밀이나헤어리베치의파종은파종방법에상관없이녹비작물의생장기간이짧아서토양이나수체생장에영향을크게끼치지는못한것으로판단되었다. 결론 Sep-, Nov-, or Jan-Mono are referred as rye seeding in Nov- and Jan-Mix are referred as rye+hairy vetch seeding in Means separation within columns by Duncan s multiple range test at P < 0.05. Fig. 3. Leaf N, P, and K concentrations at a Niitaka pear trees as affected by seeding time and method. 본연구는무농약배과원에서녹비작물파종시기와방법에따라토양에공급되는환원량과이에따른토양과배나무의잎의무기성분의변화와과실품질에미치는영향을조사하였다. 각각의처리내용에대한요약은다음과같다. 호밀 9 월하순파종 (9월단파 ), 호밀 11월중순파종 (11월단파 ), 호밀 1월하순파종 (1월단파 ), 호밀 + 헤어리베치 11월중순파종 (11월혼파 ), 호밀 + 헤어리베치 1월하순파종 (1월혼파 ), 방임초생 ( 대조구 ) 으로구성하였고, 녹비작물과방임초생은총
16 LIM et al. 2년동안 4월과 5월에두차례예초하여서토양에멀칭하였다. 11월혼파처리는녹비작물의건물중생산량을 1,207 kg/10 a으로가장크게증가시켰고방임초생구가 652 kg/10 a 으로가장낮았고, 1월혼파도 703 kg/10 a으로낮은수준을보였다. 11월혼파처리는녹비작물의잠재적인질소와인그리고칼륨공급량을향상시켰고토양물리성또한개선시켰다. 이에따라 11월혼파는예초후 5월조사에서전체적으로토양의 ph, EC, 유기물, 그리고인산농도를다른처리구또는방임초생구보다증가시키는경향을나타내었다. 배나무의엽의시기별무기성분농도와배과실품질비교는처리간에일관성있는결과가나타나지않았다. 11월혼파는화학비료를대체하는역할을보여주었다. 늦은시기 (1 월 ) 의녹비작물파종은재배시기가짧아서녹비작물로서의기능을보여주지못하여파종시기가녹비환원량에영향을미친것으로판단된다. Acknowledgment We would like to thank to Pear Research Station, National Institute of Horticultural & Herbal Science and Jeonnam Agricultural Research and Extension Services for financial support and assistance of this project. Additional thanks go to the Catholic University of Daegu for providing assistance. References Barker, A.V., 2010. Management of green manuring, in: Science and Technology of Organic Farming, CRC press, Boca Raton, USA, pp. 105-112. Choi, H.S., Rom, C.R., Gu, M., 2011. Plant performance, and seasonal soil and foliar nutrient variations in an organic apple orchard under four ground cover management systems, J. Am. Pom. Soc. 65, 130-146. Environmental-Friendly Agriculture Research Center, 2010. Organic rice manual, in: Nutrient Management Manual for Dynamic Natural Farming System, Chonnam National University Publication, Gwangju, Korea, pp. 1-166. Fageria, N.K., Baligar, V.C., Bailey, B.A., 2005. Role of cover crops in improving soil and row crop productivity, Commun. Soil Sci. Plant Anal. 36, 2733-2757. Faust, M., 1989. Physiology of Temperate Zone Fruit Trees, pp. 53 132 A Wiley-InterScience Publication, Beltsville, USA. Koehn, A.C., Peryea, F.J., Neilsen, D., Hogue, E.J., 2002. Temporal changes in nitrate status of orchard soils with varying management practices, Commun. Soil Sci. Plant Anal. 33, 3621 3634. Lawson, A., Fortuna, A.M., Cogger, C., Bary, A., Stubbs, T., 2013. Nitrogen contribution of rye-hairy vetch cover crop mixtures to organically grown sweet corn, Renew. Agr. Food Syst. 28, 59-69. Lim, K.H., Choi, H.S., Kim, H.J., Kim, B.S., Kim, D.I., Kim, S.G., Kim, J.S., Kim, W.S., Lee, Y., 2011. Effects of seeding time on growth and nutrient contribution of ryegrass and hairy vetch, J. Bio-Environ. Control 20, 134-138. Lim, K.H., Choi, H.S., Na, Y.G., Song, J.H., Cho, Y.S., Choi, J.J., Choi, J.H., Jung, S.K., 2012. Nutrient contribution and growth of Niitaka pear trees as affected by mix-seeding and single-seeding of rye and hairy vetch, Korean J. Intl. Agri. 24, 70-75. Mass, E.V., 1993. Salinity and citriculture, Tree Physiol. 12, 195-216. Nagy, P.T., Holb, I.J., 2006. Study on the macronutrient content of apple leaves in an organic apple orchard, J. Cent. Eur. Agric. 7, 329 336. Reil, W.O., 2007. Orchard establishment, in: Mitcham, E.J., Elkins, R.B. (Eds), Pear: Production and handling manual, University of California Agriculture and Natural Resources Publication, Oakland, USA, pp. 45-50. Rosecrance, R.C., McCarty, G.W., Shelton, D.R., Teasdale, J.R., 2000. Denitrification and N mineralization from hairy vetch (Vicia villosa Roth) and rye (Secale cereale L.) cover crop monocultures and bicultures, Plant Soil, 227, 283-290. Sainju, U.M., Whitehead, W.F., Singh, B.P., 2005. Biculture legume-cereal cover crops for enhanced biomass yield and carbon and nitrogen, Agron. J. 97, 1403-1412. Tagliavini, M., Tonon, G., Scandellari, F., Quiñones, A., Palmieri, S., Menarbin, G., Gioacchini, P., Masia, A., 2007. Nutrient recycling during the decomposition of apple leaves (Malus domestica) and mowed grasses in an orchard, Agric. Ecosyst. Environ. 118, 191-200. Tutua, S.S., Goh, K.M., Daly, M.J., 2002. Decomposition and nitrogen release of understorey plant residues in biological and integrated apple orchards under field conditions in New Zealand. Biol. Fertil. Soils 35, 277-287. Weinbaum, S.A., 2007. Nitrogen fertilization, in: Mitcham, E.J., Elkins, R.B. (Eds), Pear: Production and handling manual, University of California Agriculture and Natural Resources Publication, Oakland, CA, USA, pp. 131-134. Westwood, M.N., 1993. Temperate-Zone Pomology, pp. 192 199 Timber Press, Portland, USA.