Korean J. Soil Sci. Fert. Vol.51, No.3, pp.296-305, 2018 Korean Journal of Soil Science and Fertilizer Article https://doi.org/10.7745/kjssf.2018.51.3.296 pissn : 0367-6315 eissn : 2288-2162 Estimation of Optimum Organic Fertilizer Application under Fertilizer Recommendation System Seok cheol Kim, Byong Gu Ko 1, Seong Jin Park, Myung Sook Kim, Seong Heon Kim, and Chang Hoon Lee* Soil & Fertilizer Management Division, National Academy of Agricultural Sciences, Rural Development Administration, Wanju 55365, Korea 1 Organic Agriculture Division, National Academy of Agricultural Sciences, Rural Development Administration, Wanju 55365, Korea *Corresponding author: chlee915@korea.kr This author contributed equally to this works as corresponding authors A B S T R A C T Received: July 27, 2018 Revised: August 29, 2018 Accepted: August 31, 2018 Organic fertilizer has been one of soil management to improve crop productivity and soil fertility. Unfortunately, there is little information on optimum level of organic fertilizer for crop cultivation. In this study, we were tried to use the fertilizer recommendation system for determining organic fertilizer application under upland soil condition. This work was carried out; 1) to compare the effects of organic fertilizer and compost application on yields of Chinese cabbage, and 2) to estimate optimum levels on three types of organic fertilizer of 0, 50, 100, 200, and 400% with 320 kg N ha -1. The yield of Chinese cabbage in organic fertilizer plots was ranged from 71.3 to 74.1% compared to yield index of NPK. which was 2-7 times higher than in compost treatments due to improvement of N uptake efficiency. However, organic fertilizer was required addition of about 1.5-2.0 times amount to the 4 Mg ha -1 to gain the same yield of NPK treatment, these was similar soil properties of NPK treatments. This result indicated that fertilizer recommendation system could be alternative to calculate optimum levels of organic fertilizer for crop cultivation in upland soil. Keywords: Organic fertilizer, Nitrogen use efficiency, Optimum replacement rate Investigation of optimum application rate by organic fertilizers types. C The Korean Society of Soil Science and Fertilizer. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non- Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Estimation of Optimum Organic Fertilizer Application under Fertilizer Recommendation System 297 Introduction 유기질비료는화학비료를절감하거나대체하는방안이되기도하며, 친환경농업에서는유기질비료의사용을추천하고있다 (Yun et al., 2011). 유기질비료는동 식물성원료및퇴비등을혼합하여만들어지며비료공정규격상부산물비료로구분된다 (RDA, 2017). 퇴비화과정을거친부숙유기질비료 ( 퇴비 ) 와달리, 유기태화합물이다량함유하고있는유기질비료는토양중에서무기화과정을거쳐작물생육에필요한질소및인등의양분을공급할수있다 (Cho et al., 2009). 유기질비료는 2003년 208천톤에서 2007년 549천톤으로공급이증가하는추세에있지만 (Lee et al., 2009), 작물재배를위한유기질비료의시용방법은농가경험에의존하고있는실정이다. 농경지에서벼, 옥수수, 상추, 쑥갓재배에유기질비료시용효과에대한평가는많이이루어졌다 (Lim et al., 1990; Lim et al., 1983; Kim et al., 1998). Cho et al. (2009) 은유기질비료 1.46, 2.92, 4.38 Mg ha -1 를논에시용한결과, 벼정조지수는 NPK 대비약 102, 121, 90% 로유기질비료시용량에따라수량의차이가난다고하였다. 또한유기질비료시용은용적밀도, 투수성및통기성, CEC, ph 및유효인산등토양특성에영향을미치기도한다 (Mader et al., 2002; Diacono and Montermurro, 2012; Lim et al., 2011; Choi et al., 2010; Yun, 2009). 그러나유기질비료의과다시용은토양중염류를축적시켜작물의수분흡수를저해하고, 이온독성을유발하여작물생육장애를초래한다 (Cho and Park, 2002). 또한관개및강우등에의한축적된양분이주변수계로이동할경우에는수질에영향을줄수있다 (Lee et al., 2011). 이러한측면에서유기질비료의적정시용은지속적작물생산및환경보전을위한방안이될수있다. 현재농경지에적정한비료를시용하는방법으로작물별표준시비추전량또는토양검정시비체계를활용하고있다 (RDA, 2017). 특히, 토양검정시비는토양비옥도와작물수량간에관계를고려하기때문에, 비료의적정시용을유도하고작물수량감소를예방할수있다. 이러한장점으로토양검정시비체계는유기질비료의시용을결정하는데이용되었다 (Yoon et al., 2012; Uhm et al., 2012). 그러나유기질비료는무기화과정을통해양분을작물에공급하기때문에 (Alexandratos, 1995; Kim et al., 2014; Tei, 1999), 작물에대한유기질비료시용효과를검정할필요가있다. 많은연구에서작물수량및양분흡수율을대상으로유기질비료의시용효과를평가하고있다 (Simamoto and smith, 2000; Kim et al., 1998; Lim et al., 2011). 그럼에도불구하고유기질비료의시용에따른작물의질소이용효율를평가한연구는미미한실정이다. 본연구는부산물비료로구분되는유기질비료와퇴비의시용효과를비교하였고, 유기질비료종류별시용수준에따른작물수량과토양특성을평가하여유기질비료의적정시용을위한토양검정시비체계의활용가능성을검토하였다 Materials and Methods 포트재배본시험에사용된부산물비료는유기질비료 3종 ( 혼합유박, 혼합유기질, 유기복합비료 ) 과퇴비 2종 ( 가축분퇴비, 퇴비 ) 으로총 5종을사용하였고, 시험토양은식양토로국립농업과학원내시험포장에서채취하여포트재배에이용하였다 (Table 2). 와그너포트 (1 5000a -1 ) 에모래를 5 cm 깊이로채우고, 토양충진은용적밀도 1.2 g cm -3 및높이 20cm 조건을적용하였다. 배추재배시험을위한부산물비료의시용량은토양검정질소시비량을이용하여 Eq. (1) 과같이산정하였다 (Yun et al., 2009). 부산물비료시비 (kg ha -1 ) = 토양검정 N 시비 (kg ha -1 ) [100/ 부산물비료질소함량 (%)] (1)
298 Korean Journal of Soil Science and Fertilizer Vol. 51, No. 3, 2018 본시험에서부산물비료의시용효과비교와시비수준별수량과토양특성평가는 4반복의완전임의배치법으로수행되었다. 우선부산물비료의시용효과비교시험은토양검정 320 kg ha -1 에상응하는각부산물비료의시용량을산정하였다. 이때, 혼합유박 3.74 Mg ha -1, 혼합유기질비료 4.2 Mg ha -1 및유기복합비료 3.78 Mg ha -1 로, 부숙유기질비료인가축분퇴비는 22 Mg ha -1 및퇴비 35 Mg 10a -1 을전량밑거름으로시용하였다. 또한또한유기질비료 3종의시비수준에따른작물생산성과토양특성변화를평가는 320 kg ha -1 에상응하는유기질비료시용량을 100% 으로하여 0, 50, 100, 200, 400% 의 5수준을전량밑거름으로시용하였다. 대조구 (NPK) 는 N-P 2 O 5 -K 2 O : 320-78-198 kg ha -1 을요소, 용성인비, 염화가리을사용하였으며, 밑거름은 110-78-110 kg ha -1 을, 웃거름은 210-0-88 kg ha -1 로시비하였다. 물관리는 2016년 9월부터 11월까지중량수분 25% 범위로관수하였다. 질소이용효율포트재배 70일경과후배추를수확하였고, 엽폭및엽장, 생체중을조사하였고, 70 건조기에서 48시간건조한다음수분을정량하였다. 질소의이용효율을조사하기위해국립농업과학원에서발간한토양및식물체분석법 (NIAST, 2000) 에준하여실시하였으며, T-N은습식분해 (HClO 4 ) 하여전처리후킬달분석하였다. 부산물비료의질소이용효율 (%) 은아래와같이 Eq. (2) 식을이용하여산출하였다 (Yoon et al., 2012). 질소이용효율 (%) = 각처리구배추질소흡수량 (kg/ha) 무비구질소흡수량 (kg/ha) 질소총시비량 (kg/ha) 100 (2) 토양분석토양분석은국립농업과학원에서발간한토양및식물체분석법 (NIAST, 2000) 에준하여실시하였다. 토양의 ph 및 EC는풍건조건에서건조한시료와증류수를 1:5 (w/v) 비율로 30분교반하여 ph meter (Orion star A121) 및 EC meter (Orion star A121) 로각각측정하였다. 토양의전탄소 (TC) 및전질소 (TN) 는토양시료를 10 g을막자사발로곱게갈은다음에원소분석기 (Vario Max, Elementar) 로정량하였다. 가용성질소함량은 2M KCl로추출한여액을이용하여질소자동분석기 (Bran-Luebbe, AutoAnalyzer 3) 로여액중 NH 4 -N 및 NO 3 -N을측정하였다. 통계분석모든데이터는 ANOVA 분석을실시하였고, 각처리간에평균비교는유의수준 5% 로 Duncan 분석하였다. 또한유기질비료의시용에따른작물수량반응을예측하기위해유의수준 5% 로회귀분석을하였다. Results and Discussion 부산물비료시용효과부산물비료의무기화는성상및탄질비차이로달라지며, 작물생산성에영향을미치기도한다 (Kang et al., 2002; Cho and Chang, 2007; Yang et al., 2008; Cho et al., 2009). Table 1의결과와같이, 유기질비료의배추수량은평균 219 g plant -1 로퇴비에비해약 2-7배높았다. Uhm et al. (2012) 은토양에시용되는유기질비료의무기화는 30일경에는 61.2-65.0%, 60일후에는 71.4-75.6% 가이루어진다고보고하였다. 또한 Kim et al. (2000) 은토성에따라무기화차이가있다고보고하였고, 특히식양토에서가축분퇴비및퇴비의질소무기화는 16-48% 이라고하였다. 부산물비료종류에관계없이토양검정시비체계의질소시비에대응한부산물비료를농경지에시용한다면, 토양중질소무기화가촉진되는유기질비료가배추수량의증수효과가높을것으로사료된다. 또한
Estimation of Optimum Organic Fertilizer Application under Fertilizer Recommendation System 299 발효및부숙공정을거친안정화된퇴비는토양중무기화가낮기때문에배추의수량증대효과는미미할것으로판단된다. Table 1. Yield characteristics of Chinese cabbage in soil applied with different various organic fertilizer types. Treatments Control NPK Organic fertilizer Fertilizer types Height Periphery Quantity (cm) (cm) (g ea -1 ) Index - 10.8 e 12.8 c 24.0 d 8.0-25.3 a 43.0 a 303.0 a 100.0 MEC 20.0 b 42.8 a 220.0 b 73.2 MOM 21.0 b 40.3 a 223.5 b 74.1 OCF 20.5 b 42.0 a 214.3 b 71.3 AMC 15.8 c 29.5 b 103.8 c 34.5 Compost CM 13.8 d 17.0 c 30.8 d 10.2 Note) MEC : mixed expeller cake, MOM : mixed organic matter, OCF : organic complex fertilizer, AMC : animal manure fertilizer, CM : compost. Different letters indicate statistics significance at 5% level. 부산물비료종류별배추의질소이용효율을평가하였다 (Table 4). 유기질비료를시용한배추의질소함량은 1.6-2.1% 로, 유기질비료종류는배추의질소함량에영향을주었다 (p<0.01). 배추의질소이용효율은무기질비료가 4.4% 로가장높았고, 혼합유박 (3.7%) > 혼합유기질 (2.6%) 유기복합비료 (2.6%) > 가축분퇴비 (0.8%) > 퇴비 (0.3%) 순으로낮았다. 부산물비료중배추의질소이용효율이가장높은혼합유박처리구는 NPK 대비할경우 84.1% 이었고, 혼합유기질및유기복합처리구에비해질소이용효율은약 30% 향상되었다. 토양의질소공급은작물생육및수량반응에주요인으로작용한다 (Schulten and schnizer, 1998). 특히유기질비료는다양한유기태질소를함유하고있기때문에, 유기질비료의원료에따른토양중무기화속도가달라질수있다 (Cho and Chang, 2007). Table 2와같이, 유기질비료종류에따른배추의질소이용효율차이를유도한것으로판단되며 (Lee et al., 2011), 유기질비료의종류에따라무기화속도가다르기때문에배추의질소이용효율이차이가난것으로판단된다. Table 2. Nitrogen use efficiency of Chinese cabbage in soil applied with different various organic fertilizer types Treatments Control NPK Organic fertilizer Fertilizer types T-N Nitrogen use efficiency (%) (%) Index - 1.2 c - - - 1.9 ab 4.4 a 100 MEC 2.1 a 3.7 b 84.1 MOM 1.6 bc 2.6 c 59.1 OCF 1.6 bc 2.6 c 59.1 AMC 1.3 c 0.8 d 18.2 Compost CM 2.0 ab 0.3 e 6.8 Note) MEC : mixed expeller cake, MOM : mixed organic matter, OCF : organic complex fertilizer, AMC : animal manure fertilizer, CM : compost. Different letters indicate statistics significance at 5% level.
300 Korean Journal of Soil Science and Fertilizer Vol. 51, No. 3, 2018 수확기토양의화학적특성을조사한결과는 Table 3과같다. 토양 ph는배추의질소이용효율이가장높았던혼합유박 (MEC) 시용은토양 ph 에영향을미쳤다. 혼합유박처리구의토양 ph는 4.87로 NPK에비해약 6.9% 감소되었다. 혼합유기질 (MOM) 과유기복합 (OCF) 는토양 EC를 0.26 ds m -1 이었고, 혼합유박 0.19 ds m -1 에비해높았다. 유기질비료시용은토양 EC를 5.8~16.1% 증가되는경향을나타낸다 (Uhm et al., 2012). 이러한유기질비료종류에따른토양 ph와 EC의변화는유기질비료시용에따른무기화와작물의양분이용효율에의해영향을받을수있다. 혼합유박처리구에서배추의질소이용효율과가용성 NH 4 -N 함량은 3.7% 와 20.8 mg kg -1 로유기질비료중가장높았다 (Table 2와 3). 이는유기질비료의무기화가영향을미친것으로판단된다. 유기질비료의시용은토양탄소및질소함량을증가시키지않았으나, 부숙유기질비료 ( 퇴비 ) 는증가되었다. 또한토양유효인산은부숙유기질비료에의해증가되었는데, 이는가축분, 음식물등원료에포함된인산함량과관련이있을것으로추정된다. 이상의결과에서토양검정질소시비량320 kg ha -1 에부합하는유기질비료의시용은질소공급이가능하지만 NPK 배추수량의약 70% 수준을나타내었고, 특히토양 ph와 EC 변화에영향을미치는것으로조사되었다. 따라서유기질비료의적정시용량산정방법으로토양검정시비체계를활용하기위해서는유기질비료의시용에따른배추수량의반응을예측할필요가있을것으로판단되었다. Table 3. Chemical properties in soil applied with different fertilization at harvesting stage ph EC TC TN Av.P 2 O 5 Ex.cation (cmol kg -1 ) Extractable N (mg kg -1 ) (1:5) (ds m -1 ) (%) (%) (mg kg -1 ) K Ca Mg Na NH 4 -N NO 3 -N Control - 5.88 b 0.16 c 5.90 c 0.72 b 64.7 c 0.27 c 4.54 b 2.08 cd 0.10 c 13.7 b 1.1 c NPK - 5.23 bc 0.15 c 6.14 c 0.61 b 65.4 c 0.13 d 4.23 b 1.92 d 0.05 c 16.9 ac 4.5 a Organic fertilizer MEC 4.87 c 0.19 bc 6.40 bc 0.69 b 66.0 c 0.13 d 4.30 b 1.99 d 0.08 c 20.8 a 3.2 ab MOM 5.38 bc 0.26 ab 6.88 bc 0.59 b 66.8 c 0.13 d 4.38 b 2.04 cd 1.01 a 14.2 b 3.2 ab OCF 5.49 bc 0.27 ab 7.59 b 0.73 b 83.2 b 0.15 d 4.30 b 2.19 c 1.03 a 13.5 b 1.7 bc AMC 6.93 a 0.35 a 10.57 a 1.06 a 175.0 a 0.50 a 6.33 a 2.79 a 0.17 b 16.6 ab 0.3 d Compost CM 6.90 a 0.32 a 9.60 a 1.02 a 73.8 bc 0.39 b 20.27 a 2.45 b 0.20 b 15.6 b 2.2 bc Note) MEC : mixed expeller cake, MOM : mixed organic matter, OCF : organic complex fertilizer, AMC : animal manure fertilizer, CM : compost. Different letters indicate statistics significance at 5% level. 유기질비료시용수준별수량반응토양검정질소시비에대비한유기질비료종류에따른시용수준별배추수량반응을예측한결과는 Fig. 1과같다. 유기질비료에시용량이증감함에따라배추수량은증가하는경향을나타내었다. 그러나 NPK와동일한배추수량을얻기위해서는토양검정질소시비 320 kg ha -1 에대비한유기질비료 ( 약 4 Mg ha -1 ) 의 1.5 2배를시용해야했다. 논에유기질비료를약 4 Mg ha -1 를시용할경우, 벼정조수량은 NPK 수량대비 10% 감소되었다 (Cho et al., 2009). 그러나본시험에서는최대 8 Mg ha -1 의유기질비료를밑거름으로시용하더라도배수의수량은감소되지않았는데, 이는논과밭토양조건에서환원장애발달의차이일수있다 (Kim et al., 1997). 또한 Table 1과같이낮은토양비옥도가유기질비료의무기화속도에영향을미친것으로판단된다. 유기질비료종류에따른시용수준별배추의질소이용효율을평가한결과는 Fig. 2와같다. 혼합유박을약 4 Mg ha -1 시용할경우에배추의질소이용율은가장높았다. 이후혼합유박시용이증가함에따라배추의질소이용효율은
Estimation of Optimum Organic Fertilizer Application under Fertilizer Recommendation System 301 감소되었다. 혼합유박을제외한유기질비료는시용량이증가하더라도배추의질소이용효율의감소는미미하였다. 유기질비료의시용량이증가함에따른질소이용효율의감소는토양중질소등양분이축척될수있음을의미하며 (Cho and Park, 2002), 결국장기간유기질비료의시용으로작물생육을저해하거나환경부하를가중시키는원인이되기도한다. 따라서토양검정시비체계를이용한유기질비료의적정시용은작물의질소이용효율증가에따른작물생산성향상과환경보전을위한합리적인유기질비료시용방법의대안이될수있을것으로여겨진다. Fig. 1. Change of yields by organic fertilizer replacement rates.
302 Korean Journal of Soil Science and Fertilizer Vol. 51, No. 3, 2018 Fig. 2. Variation of nitrogen use efficiency by replacement rate of organic fertilizers. 유기질비료의시용수준에따른토양의화학적특성변화에대해평가하였다 (Fig. 3). 유기질비료시용은 ph를감소시키는경향을나타내었다. 그럼에도불구하고 NPK 처리구의토양 ph와는뚜렷한차이를나타내지않았으며, Yang et al. (2008) 이보고한결과와유사하였다. 토양 EC의경우에는유기질비료의시용에영향을받았다. 유기질비료의시비량이증가할수록토양 EC도동반증가하는경향을보였으며, 특히혼합유기질비료의경우는과량 (16 Mg ha -1 ) 시용함에따라토양 EC는 NPK처리구대비약 2배가량증가되었다. 토양중 TC와 TN은 8 Mg ha -1 이상의유기질비료를시용할경우에높아졌고, 가용성질소인 NH 4 -N 및 NO 3 -N 함량또한유기질비료의시용량에영향을받는것으로조사되었다. 유기질비료의경우발효가잘되어진퇴비와달리발효가진행되지않는미부숙 (Kang et al., 2002) 상태이고, C/N비가퇴비에비해낮고이로인해미생물에의한질소무기화가빨라 (Cho el al., 2000), 토양중으로 NH 4 -N 및 NO 3 -N의공급이증가된다. 토양중가용성질소가과다한경우는토양 EC증가에영향을준다는보고가있다 (Kang et al., 1997). 본실험의경우도유기질비료의과다시용으로 EC 및가용성질소의농도가증가됨을확인하였다. 이는유기질비료를과다하게시비할경우에토양에잔류되는양분으로인해작물생산에영향을미칠수있을것으로판단된다. Conclusions 토양검정으로산정된질소시비량을기준으로토양에시용된유기질비료의시용효과와더불어적정유기질비료의시용량을추정하였다. 토양검정질소시비기준으로시용된유기질비료는 NPK 배수수량대비 71.3-74.1% 생산성을보였고, 배추의질소이용효율의향상으로퇴비의배추수량보다약 2-7배높았다. 그러나 NPK의배추수량을얻기위해서는토양검정질소시비 320 kg ha -1 로산정된유기질비료의시용량의 1.5-2배더시용해야하는것으로평가되었다. 이때, 토양 ph, EC 등의토양특성은 NPK 처리구와유사하였다. 토양검정질소시비산정체계는적정유기질
Estimation of Optimum Organic Fertilizer Application under Fertilizer Recommendation System 303 Fig. 3. Chemical properties in soil applied different organic fertilizers after harvesting. MEC : mixed expeller cake, MOM : mixed organic matter, OCF : organic complex fertilizer. 비료시용량을산정방법으로활용할수있었다. 그러나유기질비료의종류에따라적정시용량이차이를나타내어이를보완하기위해유기질비료의질소무기화에대한평가도함께이루어져할것으로여겨진다.
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