Effect of Rice-straw Biochar Application on Rice (Oryza sativa L.) Root Growth and Nitrogen Utilization in Acidified Paddy Soil

Transcription

1 INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY ISSN Print: ; ISSN Online: /21x/ DOI: /IJAB/ Full Length Article Effect of Rice-strw Biochr Appliction on Rice (Oryz stiv L.) Root Growth nd Nitrogen Utiliztion in Acidified Pddy Soil Yiki Zhng 1, Huizhe Chen 1, Gungmei Ji 1,2, Yuping Zhng 1*, Jing Xing 1, Sumer Anwr 1 nd Defeng Zhu 1* 1 Stte Key Lortory of Rice Biology, Chin Ntionl Rice Reserch Institute, Hngzhou, Zhejing, 316, P.R. Chin 2 Rice Reserch Institute of Guizhou Province, Guiyng, Guizhou, 556, P.R. Chin * For correspondence: cnrice@qq.com; cnrrizyp@163.com 1 These uthors contriuted eqully to this work Astrct Soil cidifiction nd low nitrogen (N) utiliztion efficiency re serious prolems in rice production. Biochr hs the potentil to provide liming effect nd strong nutrient dsorption, leding to soil improvement. This study ws conducted to investigte specific root trits in rice nd to ssess the effect of rice-strw iochr mendment on nitrogen efficient utiliztion in cidified soil. Addition of 2 g kg -1 iochr nd wshed iochr significntly promoted rice growth nd the yield incresed y over 35% nd 24%, respectively, when compred with the control. Appliction of equivlent lime did not increse the rice yield in either low or high N tretments. Biochr ppliction llevited soil cidity nd improved the ville nutrient content. Biochr mintined high ville N during the N depletion period y regulting N dsorption nd relese in the cidified pddy soil. Biochr or wshed iochr mendment ws found to significntly improve root growth when compred with the control, prticulrly root mss nd dventitious root length. However, ppliction of equivlent lime only significntly promoted the growth of root system efore pnicle initition stge. When compred with the liming effect, the dsorption properties of iochr provided persistent effect in improving cidified soil. Further studies on long-term effects of iochr ddition on crop growth s well s its ehvior in soil re required in future. 218 Friends Science Pulishers Keywords: Biochr; Liming effect; Adsorption; Root; Nitrogen efficient utiliztion Introduction Soil cidifiction nd low nitrogen utiliztion efficiency re the serious prolems for crop production nd seriously restricts sustinle griculturl development (Jnssen, 1998). Long-term oservtions hve shown tht the verge ph vlue of pddy soil declined y units in the pst 3 yers in Chin (Li et l., 214). The excessive use of nitrogen (N) fertilizer could e responsile for regionl soil cidifiction (Guo et l., 21). Nitrogen plys n importnt role in rice growth nd development, nd increses in N fertilizer ppliction hve een mjor mngement strtegy for high-yielding rice cultivtion (Cssmn et l., 23). Finlly, the verge mount of N pplied in pddy fields ws 3 kg N h -1 in some countries (Peng et l., 26). Nevertheless, N utiliztion efficiency in crop production ws reltively lower, nd more thn 55% of the pplied N ws not tken up y rice (Run nd Johnson, 1999). The residue of excessive N in the soil ccelerted soil cidifiction of griculturl ecosystems. The min direct effect of soil cidifiction is to inhiit the growth of root system (Zhng et l., 215), which reduces the N sorption of plnts, therey decresing the N use efficiency of chemicl fertilizers. It is therefore desirle to find efficient nd comprehensive strtegies tht reduce N residue in the soil nd improve N use efficiency while mitigting soil cidifiction. Biochr produced vi the pyrolysis of crop residues is novel mteril with potentil for soil improvement (Irhim et l., 213). Some reports suggest tht dding iochr to soil ws n effective pproch to gin gronomic enefits including enhncing wter holding cpcity (Bsso et l., 213), incresing the vilility of nutrients (Borchrd et l., 212) improving the soil physicl properties (Mjor et l., 21), promoting the ctivities of soil microorgnisms (Pereir et l., 215), nd controlling contminnt vilility (Brennn et l., 214). Differing from most conventionl soil orgnic mterils, iochr s soil mendment mteril could mintin higher productivity in the long-term (Chn et l., 28). Biochr still contins high quntities of sh, which directly provides some nutrients (Xu et l., 213). Additionlly, sh content provides the liming effect of iochr. The direct effect of iochr on the soil is tht the ph vlue of the soil will lso increse, which my decrese luminum (Al) iovilility nd toxicity of cidified soil nd increse the nutrients, especilly the vilility of phosphorus, clcium nd potssium (Yun nd Xu, 211). Moreover, the lrge To cite this pper: Zhng, Y., H. Chen, G. Ji, Y. Zhng, J. Xing, S. Anwr nd D. Zhu, 21x. Effect of rice-strw iochr ppliction on rice (oryz stiv L.) root growth nd nitrogen utiliztion in cidified pddy soil. Int. J. Agric. Biol. :

2 Zhng et l. / Int. J. Agric. Biol., Vol., No., 21x surfce re of iochr results in incresed dsorption cpcity s well s ction exchnge cpcity (CEC) of soils. This might contriute to prevention of nutrient leching, prticulrly with regrd to N moiliztion. Lehmnn et l. (23) reported tht mmonium-n (NH 4 + -N) leching ws significntly decresed fter iochr mendment, while nitrte-n leching in iochr modified soil ws higher thn tht without iochr soil. Similrly, Yoo et l. (214) oserved significnt reduction in NH 4 + -N content in rice pddy soil treted with iochr. By incresing CEC, fertilizers could e sored to the surfce of the iochr nd therey e used more efficiently y plnts. However, few studies hve een crried out to investigte the effect of the liming nd sorption chrcteristics of iochr in improvement of cidified soil. Rice is one of the min crops grown under cidic soil conditions in Chin. When the ph of pddy soil is elow 5., rice yields decresed drmticlly (Zeng et l., 214). It hs een showed tht iochr hd gret potentil for cidic soil improvement (Mrris, 26). In this pper, the effects of iochr in cidified soil on root morphology nd nitrogen utiliztion from two spects of the liming nd dsorption properties of iochr re studied, respectively, which provide theoreticl sis for the ppliction of iochr in cidified soil. Mterils nd Methods Plnt Cultivtion nd Experimentl Design The soil smple ws tken from Lngy town of Jinhu, locted in Estern Chin (N 29 '17.37", E '54.84"). The cidified pddy soil sic chemicl chrcteristics re showed in Tle 1. Prior to use, the soils were screened y 2-mm sieve. The iochr (ph 1.13, totl N g kg -1 nd totl C 62 g kg -1 ) ws produced from rice strw t 5 C in muffle furnce under oxygen-limited conditions for 2 h. The wshed iochr ws otined y rinsing with.1 mol L -1 H 2SO 4 until the queous phse reched the sme ph vlue s the cidic soil to remove of lime chrcteristics of iochr, nd then it ws rinsed thoroughly with distilled-deionized wter. The treted iochr ws dried t 8 C. A pot experiment ws conducted using the cidified pddy soils in greenhouse t the fuyng se of Chin Ntionl Rice Reserch Institute. Plnts were grown in plstic columns (25 35 cm, dimeter height) filled with 15 kg soil. The mount of nitrogen pplied s (NH 4) 2SO 4 ws 2 mg kg 1 (low N) or 3 mg kg 1 (high N), nd ech fertilizer tril consist of four tretments: the soil without iochr (), the soil meliorted with 2 g kg 1 iochr (B), the soil meliorted with 2 g kg 1 wshed iochr (WB, lkline removl nd showing the dsorption chrcteristics of iochr) nd the soil meliorted with lime equivlent to 2 g kg 1 iochr (). 5% of N fertilizer ws pplied efore trnsplnting, 3% t the tillering stge, nd the remining 2% t the pnicle stge. All the other fertilizers were pplied just efore trnsplnting. The iochr, wshed iochr nd lime were thoroughly incorported into the soil. Other nutrients were provided s follows (mg kg 1 soil): 2 P (s C(H 2PO 4) 2), 25 K (s KCl), 5 Mg (s MgSO 4), 1 C (s CCl 2). Rice seeds (Oryz stiv L., cv. Zhongzheyou 1) disinfected with 3% hydrogen peroxide for 2 min nd soked in deionized wter for 24 h. Seeds sprouted t 32 C in the drk on wet filter pper for 12 h nd were cultivted on the seedling ed on My 15, 215. The seedling ws trnsplnted on My 3, 215 with two seedlings per pot nd hrvested on 28 Septemer, 215. The crop mngement ws performed ccording to following the routine rice field production. Every tretment ws repeted y 6 times. All the pots were plced in glss greenhouse nd were re-positioned rndomly every week. The test ws set up t C (dytime) nd temperture C (night) under nturl light. Plnt Smpling nd Anlysis Plnt smpling ws crried out t the key growth stges of tillering, pnicle initition (PI), heding nd mturity. The shoots were collected nd seprted into stems, leves nd spikes (from heding) efore root smpling. The lef re ws determined y lef re nlyzer (Li-Cor 31, USA). Plnt smples dried t 7 C for 4 dys. N contents of shoot were nlyzed y micro Kjeldhl to clculte N uptke in the oveground. During the key growing periods, the rhizosphere soil ws collected. Soil minerl nitrogen including mmonium nitrogen nd nitrte nitrogen in the soil ws extrcted from soil with 2 M potssium chloride (soil/wter=1:1) nd shken for 1 h t 25 C. Then, the suspensions were filtered through filter pper, nd the concentrtions of mmonium nitrogen nd nitrte nitrogen in the filtrte were mesured y Continuous Flow Anlyzer (FOSS FIAstr 5, Denmrk). Roots were crefully wshed nd detched from the nodl ses. To mesure root length nd surfce re, the root ws plced in the glss try (3 3 cm) with shllow wter nd scnned with scnner (Epson V7, Jpn), nd then use the WinRHIZO root system to nlyze dt from digitl imges (Regent Instruments Inc., Queec, Cnd). Mesurement of grin production nd yield components followed Yoshid's procedures. Sttistics All the dt were verge vlues nd stndrd errors of verge vlues. Using vrince nlysis nd lest significnt difference (LSD) test, the effect of iochr, wshed iochr, nd lime tretment on root growth, N uptke, soil minerl N, nd rice yield were determined the sttisticl significnce using SAS ver. 9.1 (SAS Institute, Cry, NC, USA). Difference etween the vlues t P<.5 ws considered sttisticlly significnt.

3 Rice Root Growth nd Nitrogen Utiliztion y Biochr / Int. J. Agric. Biol., Vol., No., 21x Results Soil Properties The ppliction of iochr significntly improved the soil ph vlue y.77 units, while wshed iochr nd lime mendment incresed ph vlues y.33 nd.28 units, respectively, when compred with the control. The content of totl N, ville P, exchngele K, nd orgnic mtter incresed under iochr mendment when compred with the control. Biochr significntly incresed the content of totl N in soil y 51%, while soil orgnic mtter lso incresed y 86%. There were no significnt differences etween wshed versus unwshed iochrs except for the ville P nd exchngele K. In prticulr, iochr mendment significntly incresed soil ville P nd exchngele K when compred with wshed iochr. Lime mendment significntly incresed ville P y four times when compred with the control (Tle 1). Rice Root Growth Biochr nd wshed iochr mendment significntly ffected root growth (Fig. 1 nd Tle 2); root iomss, totl root length, lterl root length, dventitious root length nd root surfce re per plnt were significntly higher in the iochr mended soil compred to control with N ddition except t the tillering stge. However, totl root length, lterl root length, dventitious root length nd root surfce re per plnt were significntly greter in the lime tretment when compred with the control efore the PI stge. Root verge dimeter per plnt ws thicker in oth iochr nd wshed iochr mended soils when compred with the control. The difference in root dimeter ws minly ttriuted to dventitious roots (Fig. 1). Minerl N in Rhizosphere Soil nd its Uptke y Rice Biochr mendment ffected the soil N vilility (Tle 2 nd 3). No significnt differences in NO 3 - -N content in the iochr tretment were oserved when compred with the control under low N supply. The contents of NO 3 - -N in soil significntly incresed throughout the growth seson with the ppliction of iochr or wshed iochr compred to the control under sufficient N supply, especilly in the PI period. Menwhile, lime ppliction lso significntly incresed the NO 3 - -N content of soil. No significnt differences in NH 4+ -N content in iochr or wshed iochr mended rhizosphere soils were oserved when compred with the control under low N. NH 4 + -N content of soil decresed t the tillering nd PI stges in iochr or wshed iochr tretments when compred with the control with N ddition (P<.5). However, NH 4 + -N content of soil significntly incresed t the heding stge in iochr or wshed iochr tretments when compred with the control (P<.5). There were no significnt differences in NH 4+ -N content of soil etween the lime nd control tretments under high N. Nitrogen contents of rice were significntly ffected y either iochr or wshed iochr mendment with N ddition (Fig. 2), wheres there were no significnt differences in N uptke of rice etween equivlent lime nd control tretments under high N. No influence of the mendments on N uptke ws oserved when compred with the control under low N supply except t mturity. Rice Growth nd Yield The ppliction of iochr on the growth of rice hd positive effect nd significntly incresed shoot iomss with high N supply (Fig. 3). Similrly, rice plnts under rice strw iochr ddition exhiited significntly higher lef re thn in the control with or without N ppliction (P<.5). The ppliction of lime hd significnt impcts on rice growth t the tillering nd PI stges. Rice grin yield with iochr nd wshed iochr tretments with high N supply incresed y 35% nd 24%, respectively, when compred with the control (Tle 2 nd 4). Similr to the high N tretments, rice grin yields in iochr nd wshed iochr tretments were significntly higher t low N y 35% nd 28%, respectively, when compred with the control. Lime mendment did not increse the rice yields under either low or high N supply. The pnicle numer per plnt ws higher in oth iochr nd wshed iochr mended soil when compred with the control. The percentge of filled grins incresed y 12% nd 11%, nd grin numer per pnicle incresed y 17% nd 1% for iochr nd wshed iochr tretments thn the control, respectively. The high grin yields in iochr nd wshed iochr tretments were minly due to high percentge of filled grins, pnicle numer per plnt nd grin numer per pnicle. No significnt differences in the pnicle numer, percentge of filled grins nd grin numer per pnicle etween equivlent lime nd control tretments were oserved. Discussion Acidifiction, rtificil processes nd frming methods cuse soil degrdtion nd reduce the fertility rte of gro-ecosystems. Biochr ppliction to soil improved crop growth in cidic or cidified soil (Zhu et l., 214; Bkr et l., 215; Yu et l., 215). Results from the current study indicte tht iochr ppliction significntly incresed rice yields in cidified pddy soil (Tle 4). The contriution to rice yield ws closely relted to the improvement in soil properties. Biochr ppliction resulted in higher K content in the soil solution (Olmo et l., 215). Also, P vilility could e enhnced with the increse in ph with iochr ppliction (ph incresed from 4.6 to 5.2). Al is very toxic to plnt roots, nd n increse in ph llevites this toxic effect in cidic soil fter iochr ppliction ecuse of the liming effect s well s y the dsorption of Al 3+ on the iochr (Qin et l., 213; Zhu et l., 214).

4 Zhng et l. / Int. J. Agric. Biol., Vol., No., 21x Tle 1: Effect of iochr ppliction on cidified pddy soil chemicl properties * ph Totl N (g kg -1 ) Aville P (mg kg -1 ) Exchngele K (mg kg -1 ) Orgnic mtter (g kg -1 ) Acidified soil 4.59±.1c 1.3± ±.54c 54.95±2.78c 21.5±1.9 Lime + soil 4.87±.3 1.2± ± ±1.68c 21.59±1.88 B + soil 5.36± ± ± ± ±3.6 WB + soil 4.92± ± ±.7c 12.36± ±3.38 * ph vlue: 2.5: 1 (wter/soil); totl N content: Kjedhl method; ville P content: Bry II method; Exchngele K: NH 4OAC extrction; orgnic mtter: K 2Cr 2O 7-H 2SO 4 digestion Tle 2: Vrince nlysis of effects of N, iochr tretment, nd N iochr tretment interction on root growth, dry mtter ccumultion, N uptke, grin yield nd yield components prmeters of rice t mturity Source of vrition N level (N) Biochr tretment (B) N B Totl root length 8.15 * 5.29 * 2.52 NS Lterl root length NS 3.96 * 2.58 NS Adventitious root length *** 5.54 *.17 NS Root surfce re *** 4.35 * 1.42 NS Root dimeter *** 11.6 *** 1.14 NS Root dry weight *** 9.33 **.75 NS Shoot dry weight *** *** 5.88 * N uptke *** *** 9.41 ** Content of NH + 4 -N.85 NS 1.87 NS.1 NS Content of NO - 3 -N *** 6.35 ** 2.77 NS 1 grin weight.1 NS 3.8 NS 2.1 NS Percentge of filled grins 3.34 NS 3.22 NS 4.31 * Pnicle numer *** 3.73 * 2.24 NS Grin numer/pnicle 78.9 *** *** 1.6 NS Grin yield *** *** 5.76 ** Note: *denotes significnce t the P.5 level, **denotes significnce t the P.1 level, ***denotes significnce t the P.1 level. NS: not significnt Tle 3: Effects of iochr nd N level on the content of NH 4 + -N nd NO 3 - -N in the rhizosphere soil Tretment Tillering PI Heding Mture NH + 4 -N 3.94± ± ± ± ± ± ± ±.53 B 5.3± ± ± ±.19 WB 4.26± ± ±.1 2.9± ± ± ±.8 2.7± ± ± ± ± ±1.18c 78.15±4.26c 4.15± ±.26 W 18.92±2.12c 69.86±2.67c 4.56± ±.27 NO - 3 -N.29±.7.23±.2.23±.4.26±.5.31±.9.3±.1.59±.18.32±.5 B.34±.4.24±.2.31±.6.53±.1 WB.34±.5.46±.8.28±.8.47±.2.33±.2.23±.2.21±.3c.43±.4c.61±.1.3±.2.6±.8.74±.6c.53±.1.87±.7.48± ±.17 W.92±.29.63±.14.33±.6c 1.68±.51 Note: Tillering (the ctive tillering stge), PI (the pnicle initition stge), Heding (8% of the first spike stge), Mture (the filling ripening stge). without iochr, lime ddition (), iochr (B), wshed iochr (WB) with low N fertiliztion nd,,, W refer to high N fertiliztion ppliction. Ech vlue is the verge ± stndrd error of four replictes. Different letters indicte significnt different mening (P.5) Biochr improves the physicl properties of soil, which is eneficil to the growth of root system nd the crops (Olmo et l., 215). In the present study, iochr mendment improved rice root growth in cidified pddy soil, nd the totl root length, lterl root length nd dventitious root length significntly incresed (Fig. 1). The lterl roots ccount for the vst mjority of the totl root length, nd their sptil distriution nd density ply n importnt role in the cquisition of nutrients (Li et l., 26). Olmo et l. (215) reported tht iochr ddition promoted the increse of the specific root length nd reduction of root dimeter, indicting fine root prolifertion. Nevertheless, verge root dimeter ws thicker in iochr mended soils, nd the difference in root dimeter ws minly ttriuted to dventitious roots (Fig. 1). The distriution of dventitious roots determines the rchitecture of the root system. Long dventitious roots cn increse the distriution of verticl or horizontl roots. Aiven et l. (215) showed tht iochr mendment resulted in more extensive root systems nd improved N uptke in deep soil.

5 Rice Root Growth nd Nitrogen Utiliztion y Biochr / Int. J. Agric. Biol., Vol., No., 21x Tle 4: Effects of iochr ppliction nd N level on rice yield nd its components 1 grin weight (g) Percentge of filled grins (%) Pnicle numer/plnt Grin numer/pnicle Grin yield(g/plnt) 25.3± ± ± ± ± ± ± ± ± ±1.46 B 25.2± ± ± ± ±1.52 WB 25.3± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±.5 4.1± ± ±6.2 W 25.7± ±1. 4.3± ± ±3.64 Note: without iochr, lime ddition (), iochr (B), wshed iochr (WB) with low N fertiliztion nd,,, W refer to high N fertiliztion ppliction. Ech vlue is the verge ± stndrd error of four replictes. Different letters indicte significnt different mening (P.5) Totl root length (m/plnt) B WB W c c c Lterl root length (m) B WB W c c c 3 3 Adventitious root length (m/plnt) cc c c Root surfce re (cm 2 /plnt) Root dimeter (mm) cc c c Root dry weight (g/plnt) Tillering PI Heding Mture Tillering PI Heding Mture Fig. 1: Effects of iochr ppliction nd N level on the root morphology vriles during different growth periods. Tillering (the ctive tillering stge), PI (the pnicle initition stge), Heding (8% of the first spike stge), Mture (the filling ripening stge). without iochr, lime ddition (), iochr (B), wshed iochr (WB) with low N fertiliztion nd,,, W refer to high N fertiliztion ppliction. Ech vlue is the verge ± stndrd error of four replictes. Different letters indicte significnt different mening (P <.5) Biochr is reltively inert nd decomposes slowly nd might not supply N to plnts directly (Xu et l., 213); however, it cn chnge the soil minerl N vilility ecuse of its porous nture. In this study, iochr mendment incresed NO 3- -N content of the rhizosphere in the cidified soil. The level of NO 3 - -N ws directly influenced y the ir-filled pore spce s well s neutrl ph vlues of soil (out ph 6.7) (Olness et l., 21). The effect of lrge mcropore re nd high ph on iochr my hve role effect on N dynmics. The ddition of lime could lso promote n increse in the NO 3 - -N content (Tle 3). However, iochr mendment decresed the content of NH 4+ -N in the cidified soil t the tillering nd PI stges, nd mintined higher NH 4+ -N content t the lter growth stges. The decrese in NH 4 + -N content might e cused y the incresed ph, leding to voltile mmoni formtion (Xu et l., 213). Biochr could lso sor NH 4+ -N directly nd decrese its soluility y surfce inding of ions when the soil NH 4+ -N concentrtion ws high (Chen et l., 212). When N ws depleted during the lter growth stges of rice, the iochr tretment still mintined reltively high content of ville N in the soil. Tghizdehtoosi et l. (212) showed tht NH 4 + -N dsored y iochr ws redily ioville nd could e cptured y crops.

6 Zhng et l. / Int. J. Agric. Biol., Vol., No., 21x 5 Nitrogen ccumultion (mg/plnt) B WB W cc c Tillering PI Heding Mture d c Fig. 2: Effects of iochr ppliction nd N level on N uptke y rice during different growth periods. Tillering (the ctive tillering stge), PI (the pnicle initition stge), Heding (8% of the first spike stge), Mture (the filling ripening stge). without iochr, lime ddition (), iochr (B), wshed iochr (WB) with low N fertiliztion nd,,, W refer to high N fertiliztion ppliction. Ech vlue is the verge ± stndrd error of four replictes. Different letters indicte significnt different mening (P <.5) Shoot dry weight (g/plnt) B WB W d c Tillering PI Heding Mture Lef re (cm 2 /plnt) BC WBC W PI c c c c Heding Fig. 3: Effects of iochr ppliction nd N level on shoot dry weight nd lef re during different growth periods. Tillering (the ctive tillering stge), PI (the pnicle initition stge), Heding (8% of the first spike stge), Mture (the filling ripening stge). without iochr, lime ddition (), iochr (B), wshed iochr (WB) with low N fertiliztion nd,,, W refer to high N fertiliztion ppliction. Ech vlue is the verge ± stndrd error of four replictes. Different letters indicte significnt different mening (P <.5) The ddition of iochr could optimize NH 4+ -N nd NO 3 - -N supply in the soil y regulting N dsorption nd relese, nd improve the nutrient use efficiency of nutrients from soil nd fertiliztion. Biochr ppliction significntly incresed N uptke in rice, s noted in erlier findings of Hung et l. (214). Biochr ppliction induced the production of lrge root system nd higher root ctivity of rice in lte stge, nd then p romoted grin filling (Prtiwi nd Shinogi, 216). In our study, higher percentge of filled grins ws oserved, esides, the increse in pnicle numer nd grin numer per pnicle my explin the reson of the high grin yields in iochr tretments. Rice strw iochr provided liming nd nutrient dsorption effects, nd shows gret potentil for improving cidified pddy soil. The ddition of iochr improved rice yield y 35%, wheres the equivlent lime mendment showed no significnt yield increse when compred with the control. The liming effect of iochr contriuted to the reduction of cidity nd improved the ville nutrient content, however, the effects of those processes ws short lived when compred with the dsorption. There were no significnt differences in the grin yield etween iochr nd wshed iochr mendments. The wshed iochr hd low minerl nutrient content nd lost liming effects, however, the dsorption cpcity of iochr would e enhnced y cid tretment ecuse of the decrese in inorgnic frctions nd dissolved orgnic C (Peng et l., 216). Qin et l. (213) reported the dsorption effect of iochr showed more sustinle effect on the mitigtion of luminum toxicity thn the lime effect.

7 Rice Root Growth nd Nitrogen Utiliztion y Biochr / Int. J. Agric. Biol., Vol., No., 21x When compred with the liming effect, the dsorption of iochr mrkedly improved the growth of rice over the whole growth period in the cidified soil. Conclusion Biochr providing oth sorption nd liming effects llevited soil cidity nd improved the ville nutrient content in cidified pddy soil. Addition of iochr or wshed iochr mintined high ville N in the soil y regulting N dsorption nd relese during the lter rice growth stges. Biochr nd wshed iochr stimulted N uptke nd incresed grin yield. However, ppliction of equivlent lime did not increse the rice yield. Root growth in cidified pddy soils ws enhnced y iochr mendment, wheres the ppliction of equivlent lime significntly incresed the length nd surfce re of root only efore the PI stge. The dsorption of iochr exhiited persistent effect in improving cidified soil when compred with the liming effect. Acknowledgments This reserch ws supported y the Ntionl Nturl Science Foundtion ( ), Zhejing Provincil Nturl Science Foundtion (LY16C136), Ntionl Key Reserch nd Development Pln of Chin (216YFD281, 216YFD352), Specil Funds for the Construction of Modern Agriculturl Technology System (CARS-1-26) nd Bsic Reserch Foundtion of Ntionl Commonwel Reserch Institute (217RG4-4). References Aiven, S., A. Hund, V. Mrtinsen nd G. Cornelissen, 215. Biochr mendment increses mize root surfce res nd rnching: shovelomics study in Zmi. Plnt Soil, 395: Bkr, R.A., Z.A. Rzk, S.H. Ahmd, B.J. Sehrdn, L.C. Tsong nd C.P. Meng, 215. Influence of oil plm empty fruit unch iochr on floodwter ph nd yield components of rice cultivted on cid sulphte soil under rice intensifiction prctices. Plnt Prod. Sci., 18: Bsso, A.S., F.E. Miguez, D.A. Lird, R. Horton nd M.E. Westgte, 213. Assessing potentil of iochr for incresing wter holding cpcity of sndy soils. Gc Bioeng., 5: Borchrd, N., A. Wolf, V. Ls, R. Aeckerserg, H.W. Scherer, A. Moeller nd W. Amelung, 212. Physicl ctivtion of iochr nd its mening for soil fertility nd nutrient leching greenhouse experiment. Soil Use Mnge., 28: Brennn, A., E. Jimenez, M. Puschenreiter, J.A. Alurquerque nd C. Switzer, 214. Effects of iochr mendment on root trits nd contminnt vilility of mize plnts in copper nd rsenic impcted soil. Plnt Soil, 379: Cssmn, K.G., A. Doermnn, T.D. Wlters nd H. Yng, 23. Meeting cerel demnd while protecting nturl resources nd improving environmentl qulity. Annu. Rev. Environ. Resour., 28: Chn, K.Y., L. Vn Zwieten, I. Meszros, A. Downie nd S. Joseph, 28. Agronomic vlues of greenwste iochr s soil mendment. Soil Res., 45: Chen, C., I.R. Phillips, L.M. Condron, J.B. Golorn, Z. Xu nd K.Y. Chn, 212. Impcts of greenwste iochr on mmoni voltilistion from uxite processing residue snd. Plnt Soil, 367: Guo, J.H., X.J. Liu, Y. Zhng, J.L. Shen, W.X. Hn, W.F. Zhng, P. Christie, K.W.T. Goulding, P.M. Vitousek nd F.S. Zhng, 21. Significnt cidifiction in mjor Chinese croplnds. Science, 327: Hung, M., L. Yng, H.D. Qin, L.G. Jing nd Y.B. Zou, 214. Fertilizer nitrogen uptke y rice incresed y iochr ppliction. Biol. Fertil. Soils, 5: Irhim, H.M., M.I. Alwel, A.R.A. Usmn nd A. Alomrn, 213. Effect of conocrpus iochr ppliction on the hydrulic properties of sndy lom soil. Soil Sci., 178: Jnssen, B., Efficient use of nutrients: An rt of lncing. Field Crops Res., 56: Lehmnn, J., J.S.P.D. Silv, C. Steiner, T. Nehls, W. Zech nd B. Glser, 23. Nutrient vilility nd leching in n rcheologicl Anthrosol nd Ferrlsol of the Centrl Amzon sin: fertilizer, mnure nd chrcol mendments. Plnt Soil, 249: Li, A.F., W.Z. M nd M.K. Zhng, 214. Chrcteristics nd cuses of cidifiction of pddy soil. Act Agric. Jingxi, 26: Li, L., J. Sun, F. Zhng, T. Guo, X. Bo, F.A. Smith nd S.E. Smith, 26. Root distriution nd interctions etween intercropped species. Oecologi, 147: Mjor, J., M.A. Rondon, D.R. Molin, S.J. Rih nd J. Lehmnn, 21. Mize yield nd nutrition during 4 yers fter iochr ppliction to Colomin svnn oxisol. Plnt Soil, 333: Mrris, E., 26. Putting the cron ck: Blck is the new green. Nture, 442: Olmo, M., R. Villr, P. Slzr nd J.A. Alurquerque, 215. Chnges in soil nutrient vilility explin iochr s impct on whet root development. Plnt Soil, 399: Olness, A., D.R. Lopez, D.W. Archer, J.S. Cordes, C. Sweeney, N.S. Mttson, J. Rinke nd W.B. Voorhees, 21. Fctors ffecting microil formtion of nitrte-nitrogen in soil nd their effects on fertilizer nitrogen use efficiency. Sci. World J., 1: Prtiwi, E.P.A. nd Y. Shinogi, 216. Rice husk iochr ppliction to pddy soil nd its effects on soil physicl properties, plnt growth, nd methne emission. Pddy Wter Environ., 14: Peng, P., Y.H. Lng nd X.M. Wng, 216. Adsorption ehvior nd mechnism of pentchlorophenol on reediochrs: ph effect, pyrolysis temperture, hydrochloric cidtretment nd isotherms. Ecol. Eng., 9: Peng, S.B., R.J. Buresh, J.L. Hung, J.C. Yng, Y.B. Zou, X.H. Zhong, G.H. Wng nd F.S. Zhng, 26. Strtegies for overcoming low gronomic nitrogen use efficiency in irrigted rice systems in Chin. Field Crops Res., 96: Pereir, E.I.P., E.C. Suddick, I. Mnsour, F.N.D. Mukome, S.J. Prikh, K.M. Scow nd J. Six, 215. Biochr lters nitrogen trnsformtions ut hs miniml effects on nitrous oxide emissions in n orgniclly mnged lettuce mesocosm. Biol. Fertil. Soils, 51: Qin, L.B., B.L. Chen nd D.F. Hu, 213. Effective llevition of luminum phytotoxicity y mnure-derived iochr. Environ. Sci. Technol., 47: Run, W.R. nd G.V. Johnson, Improving nitrogen use efficiency for cerel production. Agron. J., 91: Tghizdehtoosi, A., T.J. Clough, R.R. Sherlock nd L.M. Condron, 212. Biochr dsored mmoni is ioville. Plnt Soil, 35: Xu, G., L.L. Wei, J.N. Sun, H.B. Sho nd S.X. Chng, 213. Wht is more importnt for enhncing nutrient iovilility with iochr ppliction into sndy soil: direct or indirect mechnism? Ecol. Eng., 52: Yoo, G., H. Kim, J. Chen nd Y. Kim, 214. Effects of iochr ddition on nitrogen leching nd soil structure following fertilizer ppliction to rice pddy soil. Soil Sci. Soc. Amer. J., 78:

8 Zhng et l. / Int. J. Agric. Biol., Vol., No., 21x Yu, Y.L., L.H. Xue, L.Z. Yng, S.Y. He, Y.F. Feng nd P.F. Hou, 215. Effect of iochr ppliction on pkchoi (Brssic chinensis L.) utilizing nitrogen in cid soil. Act Pedol. Sin., 52: Yun, J.H. nd R.K. Xu, 211. The meliortion effects of low temperture iochr generted from nine crop residues on n cidic Ultisol. Soil Use Mnge., 27: Zeng, Y.J., Q.H. Zhou, S.L. Wei, X.M. Tn, X.H. Pn nd Q.H. Shi, 214. Effects of soil cidifiction on the yield of doule seson rice. Act Agron. Sin., 4: Zhng, Y.K., D.F. Zhu, Y.P. Zhng, H.Z. Chen, J. Xing nd X.Q. Lin, 215. Low ph-induced chnges of ntioxidnt enzyme nd ATPse ctivities in the roots of rice (Oryz stiv L.) seedlings. Plos One, 1: e116971: 1 12 Zhu, Q.H., X.H. Peng, T.Q. Hung, Z.B. Xie nd N.M. Holden, 214. Effect of iochr ddition on mize growth nd nitrogen use efficiency in cidic red soils. Pedosphere, 24: (Received 28 Mrch 218; Accepted 11 June 218)