PARTICULATE ORGANIC MATTER AS A SOIL QUALITY INDICATOR OF SUGARCANE PLANTATIONS IN EAST JAVA

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1 AGRIVITA VOLUME 34 No. 2 JUNE-12 ISSN : PARTICULATE ORGANIC MATTER AS A SOIL QUALITY INDICATOR OF SUGARCANE PLANTATIONS IN EAST JAVA Nurhidyti 1*), Endng Arisoesilningsih 2), Didik Supryogo 3), nd. Kurnitun Hirih 3) 1) Fculty of Agriculture, Islmic University of Mlng, Est jv, Indonesi Jl. Myjen Hryono 193 Mlng Est Jv Indonesi 2) Fculty of Mthemtics nd Sciences University of Brwijy Jl. Vetern Mlng Est Jv Indonesi 3) Fculty of Agriculture, University of Brwijy Jl. Vetern Mlng Est Jv Indonesi *) Corresponding uthor Phone: E-mil: nht_unism@yhoo.com Received: My 23, 12/ Accepted: August 1, ABSTRACT The reserch tested the degree of independence of two soil qulity indictors for sugrcne plnttions: the prticulte orgnic mtter (POM) content nd erthworm density cross five sites in Mlng district, Est Jv. Sites reflected grdient in verge nnul rinfll (14-25 mm/yer) nd two types of soil mngement: with nd without orgnic input. Soil smples tken from depth of - cm were nlyzed for totl orgnic C (TOC), totl N (TN), POM-C, nd POM-N nd erthworm density nd iomss. The TOC ws corrected y the cly content using pedotrnsfer equtions, so TOC ref ws otined. The soils treted with orgnic input hd higher TOC (18%), TN (28%), POM-C (7%), POM-N (64%), erthworm density (89%) nd iomss (92%) thn the soils without orgnic input. A sttisticlly significnt interction ws found etween vrition in nnul rinfll nd soil mngement types in their influence on TOC, TN, POM-C, POM-N, erthworm density nd iomss. Increse in TOC, TOC/TOC ref, nd POM-C tend to e ssocited with increse in erthworm density (r=.59;.667;.738) nd iomss (r=.622;.732;.581). As n esily mesured indictor of iologicl soil helth, POM-C is suited for monitoring soil qulity in sugrcne plnttions: erthworm density does provide dditionl informtion tht my justify its regulr mesurement. Keywords: totl C, prticulte orgnic mtter, erthworm, soil qulity, sugrcne plnttion INTRODUCTION Soil orgnic mtter (SOM) content is seen s n importnt indictor of soil fertility nd qulity in ddition to other indictors such s soil structure, nutrient lnce nd the popultion density of iot such s erthworms (Gregorich et l., 1994). Totl C-orgnic content reltes to soil chemicl, physicl nd iologicl properties, nd processes in the soil, ut more dynmiclly sensitive indictors my e needed s prt of mngement nd monitoring systems. Totl C- orgnic content responds to soil physicl chrcteristics (e.g. cly content) s well s soil mngement prctices (Vn Noordwijk et l., 1997; Hynes, 5). It consists of vrious frctions with vrying turn-over time nd function. The CENTURY model of soil orgnic mtter dynmics (Prton et l., 1987), distinguishes SOM pool with fst turn-over (<2 yers) such s the metolic, structurl nd ctive SOM, nd slow turn-over pool (with hlf time of round 8 yers) nd pssive (stle) pool (hlf life time out two thousnd yers) tht is not ville for soil microorgnisms. Lile SOM frctions re more responsive to lnd use nd mngement prctices thn the other frctions (Cmrdell nd Elliot, 1992; Ding et l., 6): corrections for soil texturl vrition influencing the slow nd pssive pools my e needed if totl SOM is to e used cross smple loctions. Mesurements of SOM sed on prticle size nd content of C nd N, commonly clled POM-C nd POM-N (Okleo nd Gthu, 1993), hve een used extensively to evlute the effect of orgnic fertilizer types in pddy soil (Yn et l., 7) nd in mize lnd (Mtmnengwe nd Accredited SK No.: 81/DIKTI/Kep/11

2 176 Mpfumo, 8). In ddition the method is lso used to study the improvement of mrginl griculturl lnd (Mo nd Zeng, 1) nd the lnd use chnge of monocropping system to groforestry (Mo et l., 11). However, mesurements of POM s n importnt indictor to evlute the productivity of sugrcne lnd hve so fr een limited. Erthworms re importnt s prt of soil mcrofun tht cts s key regultor of soil structure nd dynmics of the SOM in the groecosystem. However, in conducting their ctivities in soil, worms re influenced y vrious fctors tht regulte popultions such s climtic conditions, soil chrcteristics nd vilility of orgnic mterils s their food source (Kle et l., 1). Therefore, the erthworm popultion density hs een used to evlute the impct of ppliction of mnure nd NPK fertilizer in the long-term (Estevez et l., 1996), the effect of vrious lnd mngement prctices (Reddy et l., 1997), ssessing the productivity of ruer plnttions (Chudhuri et l., 8) nd s ioindictor of griculturl lnd mngement prctices (Suthr, 9). It is even used s n indictor of hevy metls nd pollutnts from grochemicl residues (Mhmoud, 8). To improve soil fertility of sugrcne lnd, inorgnic nd orgnic fertilizer inputs re needed. However, the evlution of its success is still limited. Evlution of soil qulity of sugrcne lnd using simple indictors of POM nd the popultion density of erthworms needs to e done. The purpose of this study ws to test the hypothesis tht the soil qulity of sugrcne plnttion is closely linked with decresed content of POM-C nd erthworm popultion. MATERIALS AND METHODS Study Site nd Time The reserch ws conducted t five sites (Wgir, Tumpng, Ngjum, Krngploso, nd Klipre) of monoculture sugrcne plnttion re in Mlng district, Est Jv, Indonesi. The selected plots were estlished s sugrcne plnttion for more thn 1 yers under conventionl soil mngement with Inceptisol soil type. The five sites were selected sed on differences in verge nnul rinfll rnges from high to low nnul rinfll. Environmentl chrcteristics of ech site re presented in Tle 1. The reserch ws conducted during the growing seson of sugrcne in Novemer 1 to July 11. Tretment Two fctors tht were intercting in this study were rinfll nd soil mngement. The five sites differed in men nnul rinfll (Tle 1). The second fctor is the type of soil mngement, nmely the orgnic fertilizer input of sugr groindustry wste (5-1 Mg h -1 ) t lest once in three yers, nd inorgnic fertilizer only with dose of 8 kg h -1 mmonium sulfte nd kg h -1 NPKs compound fertilizer 15:15:15. Bsed on crop performnce, smpling sites in ech loction included good, verge nd poor crop with two replictes nd 4 smpling points per replicte. Soil Smpling nd Anlysis Soil smpling ws crried out etween two rows of sugrcne t depth of - cm. Four soil smples were tken from ech plot, where the distnce etween the smpling points ws 1 m. The soil smples were mixed evenly nd ir-dried, crushed nd sieved to 1-mesh sieve size. Furthermore, the soil smples were nlyzed for totl orgnic cron (TOC) (Wlkley nd Blck, 1934), totl soil N (TN) with the Kjeldhl method (Jckson, 1973), soil ph, soil texture y the pipette method of mechnicl nlysis. Undistured soil smple ws used to mesure the soil ulk density (BD) y clculting the rtio of the mss of soil y volume of soil (Okleo nd Gthu, 1993). The Corrected Totl Orgnic Cron (TOC ref ) The otined dt of TOC ws corrected with soil depth, soil ph, cly nd silt content nd ltitude, in order to otin soil TOC ref using pedotrnsfer eqution (Vn Noordwijk et l., 1997). For Inceptisol, the following eqution ws used : where: Zs = depth of soil smpling, cm H = ltitude (meter ove se level) (Vn Noordwijk et l., 1997; Hirih et l., )

3 177 Tle 1. Loction nd soil chrcteristics of the study sites Environmentl Sites Prmeters Wgir Tumpng Ngjum Krngploso Klipre Altitude (m) Ltitude (S) nd Longitude (E) Men Annul rinfll (mm) Men Annul Temp. ( o C) Soil Texture % snd % silt % cly 7 o o 5 S nd 112 o o 37 4 E 8 o 58 8 o 2 5 S nd 112 o o 5 8 E 7 o o 7 5 S nd 112 o o 37 5 E 8 o o 1 26 S nd 112 o o E 8 o o 15 5 S nd 112 o o 3 8 E Lom-clyey lom Lom Lom-clyey lom Lom-clyey lom Lom-clyey lom % Soil C-orgnic , Soil ph (H 2O) Source : Nurhidyti et l. (11) POM-Frctiontion The processed smples from ech plot were tken for Prticulte Orgnic Mtter (POM) nlysis. POM nlysis ws done y seprting the SOM frctions sed on wet sieving technique developed y TSBF (Hirih, 1996). The ir-dry soil (5 g) which hs een re-wetted, ws seprted y using wet sieve with size of, 25, 15, nd 5 μm dimeter. The mterils which retined on >5, 15, 25 µm sieves were dried in the oven t 65 o C for 24 hours, weighted, nd referred s POM-corse frction (>25μm-2 mm), POM-intermedite frction (15-25μm), nd POM-fine frction (>5-15μm). Totl orgnic cron (Wlkley nd Blck) nd totl N (Kjehldhl) were determined y every frction s prticulte orgnic mtter-c (POM-C C,I,F ) nd prticulte orgnic mtter-n (POM-N C,I,F ) (Okleo nd Gthu, 1993). Erthworm Smpling nd Assessment The popultion density (D) of erthworms ws determined from soil monoliths (25cm x 25cmx cm size), t 1 point mesurements of the 1 m x 1 m trnsect, ccording to smpling procedure descried y Huising et l., (8). Erthworm smples were collected y hnd sorting nd weighed for fresh weight (iomss, B g indiv. -1 ) mesurement. Weight per individul ws estimted y erthworm iomss nd density rtio (B/D). Sttisticl Anlysis The otined dt were sujected to nlysis of vrince (ANOVA) using progrm Minit Version to compre the interction effects of sites with different nnul rinfll nd soil mngement on the mesured prmeters. The Duncn t-test (5%) procedure ws used to seprte the mens of selected prmeters t p=.5. For sttisticl nlysis of dt (regression, correltion, nd chrts) Microsoft Excel ws used. The Person correltion ws used to relte erthworm vriles with the soil vriles. RESULTS RESULTS AND DISCUSSION Totl Soil C nd N Interction etween the sites with different rinfll nd the type of soil mngement did not significntly (p<.5) influence the totl orgnic cron (TOC org ) nd totl N (TN) of soil. Seprtely, the effect of different chrcteristics of sites nd type of soil mngement significntly (p<.5) ffected the TOC nd TN in the soils. At ll sites of the selected sugrcne plnttions, the soils treted with orgnic input were higher thn the tretments without orgnic input (Figure 1). The soils of sugrcne plnttion with orgnic input tretment contined n verge of 18.3 % C nd 27.2 % N more thn the soils of sugrcne plnttion without orgnic input. Wgir

4 178 site, the wettest res (2514 mm per yr ), hd the highest verge of TOC (16.23 g per kg) for the tretment with orgnic input, ut ws not significntly different from three other sites tht hd lower nnul rinfll such s Tumpng (14.51 g per kg), Ngjum (15.53 g per kg), nd Krngploso (14.27 g per kg) with n verge nnul rinfll s 31, 194, nd 1644 mm per yr, respectively. Klipre site hd the lowest TOC (8.5 g kg -1 ), while the highest TN due to the ddition of orgnic mtter ws found in sugrcne lnd t Tumpng site (1.62 g per kg), ut not significntly different from Ngjum (1.58 g per kg) nd Krngploso (1.53 g per kg). The Corrected Soil Orgnic Mtter (TOC/TOC ref ) The ddition of orgnic mtter into soil of sugrcne plnttions did not significntly influence (p<.5) the corrected SOM (TOC ref ). The differences in TOC ref were only significntly influenced (p<.5) y the site's fctor which hd vrious ltitude nd soil properties. The highest TOC of g kg -1 ws found t Klipre site nd the lowest vlue ws found t Tumpng site (Figure 2). 15 TOC, g kg -1 TOC/TOC ref Rtio 1 5 Totl N, g kg -1 2,5 2, 1,5 1,,5, - orgnic + orgnic c WGR TMP NGJ KRP KPR c Figure 1. The effect of orgnic mtter input to the verge totl orgnic C (TOC) nd totl soil N (TN) t five sites of sugrcne plnttions. The mgnitude of the r shows the stndrd devition (n = 6). Br vlues followed y different letters re significntly different (p <.5). (Remrks: WGR = Wgir; TMP = Tumpng ; NGJ = Ngjum; KRP = Krngploso; KPR = Klipre.) - orgnic + orgnic WGR TMP NGJ KRP KPR C-concentrtion, g kg ,5,4,3,,1, TOC Figure 2. Averge TOC nd TOC ref (A) nd the effect of orgnic input to the TOC / TOC ref (B) t five sites of sugrcne plnttions. The mgnitude of the r shows the stndrd devition (n = 6). Br vlues followed y different letters indicte significnt differences (p <.5). (Remrks: WGR = Wgir; TMP = Tumpng = Ngjum; KRP = Krngploso; KPR = Klipre) TOC-ref WGR TMP NGJ KRP KPR cd cd d d c c - orgnic + orgnic WGR TMP NGJ KRP KPR

5 C-Concentrtion, g kg -1 soil WGR TMP NGJ KRP KPR WGR TMP NGJ KRP KPR C-Proportion, (% of POM-C T ) WGR TMP NGJ KRP KPR WGR TMP NGJ KRP KPR 179 The results of clcultion of TOC/TOC ref from ll sites showed n verge vlue of less thn.5 (Fig.2), which mens tht the sugrcne lnds of the five sites cn e regrded s less helthy soil. According to Vn Noordwijk et l., (1997), the soil is clssified s helthy soil when the TOC /TOC ref is close to 1., such s in nturl forest soils. The soils of sugrcne plnttion t Tumpng site showed the highest TOC /TOC ref, ut were not significntly different from Wgir. The soil of sugrcne plnttions with orgnic input tretment hd 14% TOC/TOC ref higher thn the soil of sugrcne plnttions treted without orgnic inputs (.23). The highest increse in TOC /TOC ref ws found t Klipre site (25%), while the lowest increse t Krngploso site (1.5%) (Figure 2). POM-C nd POM-N The interction etween sites with different nnul rinfll nd the type of soil mngement in sugrcne cultivtion significntly (p<.5) ffected the C concentrtion of corse frction (POM-C C ) nd totl POM-C (POM-C T ). However, the interction effect did not ffect the POM-C I nd POM-C F. Seprtely, the influence of differences in nnul rinfll nd type of soil mngement significntly (p<.5) ffected POM-C I nd POM- C F. The ddition of orgnic mtter in the sugrcne lnds incresed POM-C C - POM-C I, nd POM-C F y 94.2, 61.4, 66.4%, respectively compred to sugrcne lnds without orgnic inputs, except for POM-C C t Klipre site (Tle 2). Tle 2. The effect of orgnic mtter input on the C concentrtion of ech frction nd its proportion of the POM-C T t five sites of sugrcne plnttion Site Tretment POM-C (g per kg soil) POM-C T POM-C (% of POM-C T) C I F (g per kg soil) C I F Wgir - Orgnic cd Orgnic cd cde 26.6 Tumpng - Orgnic de 38.9 c +Orgnic 2.29 cd e de 27. Ngjum - Orgnic c Orgnic 2.74 d e 61.2 c Krngploso - Orgnic c.2 c.9 +Orgnic de Klipre - Orgnic c 21.9 cd Orgnic e 34.7 Duncnt 5 % s ns ns S s s S Remrks: Mens followed y the different letter re significntly different (P<.5). s significnt (P<.5) ; ns non-significnt; C corse frction, I intermedite frction, F fine frction 3, 2,5 2, 1,5 1,,5, COARSE INTERMEDIATE FINE ORGANIC + ORGANIC - ORGANIC + ORGANIC Figure 3. The effect of orgnic mtter input on the C concentrtion of ech frction nd its proportion of totl POM-C t five sites of sugrcne plnttions (Remrks: WGR = Wgir; TMP = Tumpng ; NGJ = Ngjum; KRP = Krngploso; KPR = Klipre)

6 18 POM-C proportions of ech frction were influenced y the interction etween site nd type of soil mngement. Ngjum site showed the lrgest verge proportion of POM- C C to POM-C T, ut ws not significntly different from Klipre nd Krngploso site. The lrgest proportion of the POM-C I reltive to POM-C T ws found in the soil of sugr cne plnttion t Tumpng, Wgir nd Klipre sites, while the lrgest proportion of POM-C F ws found t Tumpng nd Klipre sites. The ddition of orgnic mtter only incresed the proportion of POM-C C reltive to POM-C T in the soil of sugrcne plnttion t Tumpng site. However, the ddition of orgnic mtter incresed the proportion of POM- C I reltive to POM- C T t ll sites (Tle 2 nd Figure 3), ut not for the proportion of POM- C F to POM- C T. Overll POM-C T for the soils of sugr cne plnttions treted with the orgnic input t five sites were higher thn the soils treted without orgnic input (Tle 2), except t Klipre site. The soil of sugrcne plnttions treted with orgnic input hd 7 % POM-C T higher thn the soil treted without orgnic input (2.46 g per kg). Similr results re shown in POM-N. The highest verge of POM-N C ws found in the soil of sugrcne plnttion t Ngjum site with orgnic inputs, ut it ws not significntly different from Krngploso site with orgnic input (Tle 3). The N proportion of ech frction ws influenced y the interction etween site nd type of soil mngement. Ngjum site shows the lrgest proportion POM- N C of POM-N T, ut it ws not significntly different from Krngploso site. The ddition of orgnic mtter incresed the proportion POM- N C of POM-N T t Tumpng site. The lrgest proportion POM-N I of the POM-N T ws found t Wgir, Tumpng, Krngploso, nd Klipre, while Ngjum hd the lowest proportion of POM- N I of POM-N T. However, the ddition of orgnic mtter does not increse the proportion of POM- N I of POM- N T t ll sites. The ddition of orgnic mtter incresed the proportion of POM- N F of POM- N T significntly (P<.5) t Klipre site (Tle 3). Overll POM-N T for the tretment with the orgnic input t five sites ws higher thn the tretment without orgnic input (Tle 3), except t the Klipre nd Wgir sites. Sugrcne lnds with orgnic inputs hd POM- N T 63.8% higher thn the sugrcne lnds without orgnic inputs (.26 g per kg). The highest increse in POM-C T nd POM-N T s the result of the ddition of orgnic mtter ws found t Tumpng site y 97.7% nd 96.%, respectively. Tle 3. The effect of orgnic mtter input on the N concentrtion of ech frction nd its proportion of the POM-NT t five sites of sugrcne plnttion Site Tretment POM-N (g kg -1 soil) POM-N T POM-N (% of POM-N T) C I F (g kg -1 soil) C I F Wgir - Orgnic d Orgnic d Tumpng - Orgnic d +Orgnic.21 cd cd Ngjum - Orgnic de Orgnic.29 e e Krngploso - Orgnic cde 26.6 c Orgnic.25de cde Klipre - Orgnic e Orgnic Duncnt (5%) s ns ns s s s S Remrks: Mens followed y the different letter re significntly different (P<.5). S significnt (P<.5) ; ns non-significnt; C corse frction, I intermedite frction, F fine frction

7 POM-NT (% of TN) POM-C T (% of TOC) A - orgnic + orgnic WGR TMP NGJ KRP KPR B - orgnic + orgnic e d cd cd d WGR TMP NGJ KRP KPR Figure 4. The effect of orgnic mtter input on POM-C T reltive to TOC (A) nd POM-N T reltive to totl N (B). The mgnitude of the r shows the stndrd devition (n = 6). Br vlues followed y different letters indicte significnt differences (p <.5). (Remrks: WGR = Wgir; TMP = Tumpng; NGJ = Ngjum; KRP = Krngploso; KPR = Klipre) Figure 4 shows tht the sugrcne lnd with orgnic input tretment hd higher percentge of POM-C T reltive to TOC nd POM-N T reltive to TN thn the soils of sugrcne plnttion without orgnic input. The verge of increse rte ccounted for 45.9% (POM-C T ) nd 25.4% (POM-N T ). The highest percentge of the increse in POM-C T of TOC nd POM-N T of TN ws the sugrcne lnd t Tumpng site s 78.8% nd 41.5%, respectively. Erthworm Density nd Biomss The interction etween the sites with different nnul rinfll nd the type of soil mngement in sugrcne cultivtion significntly (P<.5) ffected the erthworm density nd iomss. Tle 4 nd Figure 5 show tht the sugrcne lnd t Tumpng site with orgnic input tretment hd the highest popultion density of erthworms (269.3 individuls m -2 ), while the sugrcne lnd t Klipre site hd the lowest popultion density of erthworms either with orgnic inputs (33.3 individuls m -2 ) or without the input of orgnic (13.3 individuls m -2 ). Orgnic input into sugrcne lnds improved the erthworm density nd iomss. The verge increse in popultion density of erthworms in the tretment with orgnic input compred to the tretment without orgnic input t Wgir ws 163.8% nd Tumpng ws 169.3%, Ngjum ws 63.5%, Krngploso ws 12 % nd Klipre ws 38.8 %. The verge increse in erthworm iomss in the tretments with orgnic input compred to the tretments without orgnic input t Wgir ws 77.8%, Tumpng ws 12% nd Ngjum ws 13.6%, Krngploso ws 14% nd Klipre ws 34.8%. The interction etween the sites with different nnul rinfll nd the type of soil mngement significntly (P<.5) ffected the verge weight per individul erthworm (B/D). However, seprtely, the ddition of orgnic mtter did not significntly ffect the verge weight per individul erthworm. The highest verge weight per individul erthworm ws found t Wgir site with tretment without the input of orgnic mtter (Tle 4). DISCUSSION The soil of sugrcne plnttion with the orgnic mtter input of the five sites studied hd higher totl orgnic C (TOC) (18.3%), TOC/TOC ref (14%) nd POM-C T (7%) thn without orgnic inputs (TOC = g per kg; TOC/TOC ref =.3; POM-C T = 2.47). However, the gretest improvement ws otined in the POM-C T compred with other mesurements. The reltionship etween the three mesurements nd vrile erthworms re presented in Figure 6.

8 182 Tle 4. The effect of orgnic mtter input on the popultion density, iomss nd weight per individul (B/D) of erthworms t five sites of sugrcne plnttions Site Tretments Erthworm density (D) (individul m -2 ) Erthworm iomss (B) (g m -2 ) B/D (g individul -1 ) Wgir - Orgnic d + Orgnic 17.7 d 5.3 c.31 c Tumpng - Orgnic c + Orgnic e 6.8 c.23 Ngjum - Orgnic c Orgnic d Krngploso - Orgnic Orgnic c c Klipre - Orgnic Orgnic Duncnt 5% s s s Remrks: Mens followed y the different letter re significntly different (P<.5). S significnt (P<.5) ; ns non-significnt Erthworm Density, indiv. m Density Biomss WGR TMP NGJ KRP KPR WGR TMP NGJ KRP KPR Erhworm Biomss, g m -2 -orgnic + orgnic Figure 5. The effect of orgnic mtter input on the popultion density nd iomss of erthworms. (Remrks: WGR = Wgir; TMP = Tumpng; NGJ = Ngjum; KRP = Krngploso; KPR = Klipre) Regression nlysis showed tht the vriles TOC, TOC/TOC ref, nd POM-C T were closely relted nd significnt (p <.5) with popultion density nd iomss of erthworms, however, there is no significnt reltionship with n verge weight per individul (B/D) erthworms (Fig. 6). Third of the correltion nlysis etween these vriles, POM-C T ws more closely relted to the erthworm popultion density compred with other vriles. Vrile TOC/TOC ref ws more closely ssocited with erthworm iomss (Tle 5). Bsed on the increse in vrile TOC, TOC/TOC ref nd POM-C T in the tretment of orgnic inputs compred with the tretment without orgnic input, correltion, nd regression nlysis indicted tht the indictors of POM-C T nd TOC/TOC ref were more sensitive to ssess chnges in soil qulity nd productivity in sugrcne plnttions.

9 183 Erthworm density, indiv.m -2 Erthworm iom, g m y = 39,24x 2-62,967x + 98,817 R² =, POM-C C, g kg -1 y = 12,257x 2-3,795x + 38,98 R² =,2676 Erthworm density, indiv.m -2 Erthworm iomss, g m y = 286,19x 2-227,79x + 123,99 R² =,32,,5 1, 1,5 POM-C I,g kg -1 y = 77,772x 2-62,514x + 29,249 R² =,3554 y = 29,471e 1,2968x R² =, ,,5 1, 1,5,,5 1, 1,5 2, POM-C C, g kg -1 POM-C I, g kg -1 POM-C F, g kg-1 Figure 6. The reltionship etween POM-C C, POM- C I, nd POM-C F with the erthworms vriles Erthworm iomss, g m -2 Erthworm density, indiv.m ,,5 1, 1,5 2, POM-C F, g kg -1 y = 25,15x 1,146 R² =,3135 POM is lile frction of soil orgnic mtter. It is mjor frction of the SOM in surfce soil nd more sensitive to chnges of lnd mngement (Cmrdell nd Elliott 1992; Zhng et l., 6). In ddition, POM is uncomplexed frction of the SOM so tht it cn e sustrte for microil ctivity, nd it is lso n importnt gent in the formtion mcro-ggregte (Frnzlueer, 2; Cusrno et l., 8). POM is lso n intermedite frction of litter (with rpid turnover) nd minerl ssocited with SOM (with slow turnover). Active frction of orgnic mtter plys n importnt role in the plnt nutrient supply, decomposition of orgnic residues, nd the development of soil structure (Frnlzlueers, 2). Heightened levels of POM-C nd POM-N will increse the potentil vilility of C nd N, thus, they will increse soil fertility nd qulity (Hndyni et l., 1). The mesurement of POM-C on sugrcne lnds t five sites with two types of soil mngement rnged from g kg -1 soil. The vlues were considered slightly higher compred to the results from Hndyni et l., (1) for monoculture lnd s much s 2.24 g kg - 1 soil, while on mixed plnt lnd s much s 4.2 g kg -1 soil. These vlues were in the rnge s reported y Koutik et l., (1) nd Oedrogo et l., (6) which rnged from g kg -1 nd g kg -1. Difference in the vlues cn e cused y severl fctors such s differences in the soil mngement, climte condition nd soil chrcteristics. The reltionships etween TOC/TOC ref nd iomss of erthworms nd the high correltion coefficient were lso provided (Tle 5). This suggests tht the mesurement of these indictors cn e used to ssess the soil qulity nd helth in sugrcne plnttions. Ortiz- Cellos nd Frgoso (4) reported tht in 33% soil moisture conditions, undnce nd iomss of erthworms were higher in the soil receiving orgnic mtter input compred to conventionl soil mngement without the orgnic mtter input. This is cused y the mount of orgnic mtter nd N content is higher. Sugrcne lnd with the low TOC/TOC ref rtio showed low popultion density nd iomss of erthworms too, which indicted n unhelthy soil. Helthy soil s forest lnd usully shows TOC /TOC ref out 1. (Vn Noordwijk et l., 1997; Hirih et l., 3). Every yer, tretment of orgnic input my increse TOC/TOC ref rtio nd erthworm density nd iomss. This suggests tht to mintin the soil qulity nd helth in sugrcne plnttions in Est Jv, the ddition of orgnic

10 184 mteril hs to e done every yer. These results re consistent with those reported y Hirih et l., () suggesting tht in order to mintin soil productivity in the tropics, the SOM content should e mintined etween %. It required the orgnic mtter input s much s 8 to 9 Mg h -1 yr -1. Orgnic mtter input comined with N fertilizer every yer on the sugrcne lnd in North Lmpung cn improve soil orgnic mtter sttus in the fourth yer (Hirih et l., 3). Regression nd correltion nlysis etween the C concentrtion of ech frction (POM-C C,I,F ) indicted tht the POM-C C, POM-C I, nd POM-C F were closely relted nd were significnt (p <.5) with popultion density nd iomss of erthworm. However, there ws no significnt reltionship with n verge weight per individul (B/D) of erthworms (Tle 5 nd Figure 5). Third of the correltion nlysis etween these vriles, POM-C C were more closely relted to the erthworm popultion density compred with other vriles. This mens tht erthworm in the sugrcne plnttion is more responsive to the ddition of new orgnic mtter. Corse frction is the lile frction nd is mtter tht hs not decomposed yet (Bossuyt et l., 4; Pullemn et l., 5.). This orgnic mtter is n energy source of soil microorgnisms nd is esily degrded (Gregorich et l., 6). Similrly, erthworms prefer the new orgnic mtter, ut re prtilly decomposed to e prticle with intermedite size (> 5 μm) (Lvelle nd Spin, 1). Tle 5. Correltion coefficient of the reltionship etween soil properties nd erthworm vriles Vriles ED EB TOC.59 *.622 * TOC/TOC ref.667 **.732 ** POM-C C.63 *.42 * POM-C I.494 *.536 * POM-C F.588 *.5 * POM-C T.738 **.581 * ED 1.863** EB.863** 1 Remrks: ns = non-significnt ; *= Significnce level P <.5 ; **= Significnce level P<.1 ED = Erthworm density ; EB = Erthworm iomss ; BD = Soil ulk density ; BD ref= the corrected BD These results explin tht the presence of erthworms s io-indictor of soil qulity is lrgely determined y chnges in soil C- orgnic content, totl soil N, the lile frction of orgnic mtter (prticulte orgnic mtter), nd the vilility of N relesed y the prticulte orgnic mtter. Topolintz et l., (2) reported tht erthworm popultion density ws positively correlted with totl soil N through the positive influence of erthworms (Pontoscolex corethrurus) of N minerliztion (González nd Zou, 1999). CONCLUSIONS AND SUGGESTIONS Soil qulity of sugrcne plnttion cn e mesured y severl indictors of the TOC, the TOC/TOC ref rtio nd POM-C. Among the indictors, the TOC/TOC ref, POM-C, popultion density nd iomss of erthworms show high sensitivity to ssess chnges in soil qulity of sugrcne plnttion due to the ddition of orgnic mtter; the indictors show lrge increse when compred with the soil of sugrcne plnttion without orgnic input (conventionl) minly on sugrcne plnttions with high reltively rinfll nd low cly content. It is suggested tht to fcilitte the ssessment of soil qulity of sugrcne plnttion sed on these indictors cn e done y oserving the popultion density of erthworms in the field. For further study, the ddition of orgnic mtter nd erthworms on the productivity of sugrcne needs to e tested. ACKNOWLEDGMENTS We thnk the frmers for the soil smples s well s to provide informtion on lnd mngement, Directorte of Higher Eduction, Ministry of Eduction nd Culture of Indonesi nd the stff of the Deprtment of Soil Science, Brwijy University who contriuted in the soil nlysis in the lortory. REFERENCES Bossuyt, H., J. Six, P.F. Hendrix. 4. Rpid incorportion of fresh residue-derived cron in to newly formed stle microggregtes within erthworm csts. Eur.J.Soil Sci., 55: Cmrdell, C. A. nd E.T. Elliott Prticulte soil orgnic-mtter chnges

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