DISEASE CONTROL WITH QUALITY COMPOST IN POT AND FIELD TRIALS.

I Interntionl Conferene Septemer 15th 17th 24, León - Spin DISEASE CONTROL WITH QUALITY COMPOST IN POT AND FIELD TRIALS. Jques G. FUCHS, Mohmed LARBI FiBL, Reserh Institute of Orgni Agriulture, CH-Frik Akerstrsse, CH-57 Frik, emil: jques.fuhs@fil.org Introdution Different motivtions n e oserved with ompost produers. While wste mngement is the prinipl gol of some produers, others produe ompost in order to improve fertility of the soil nd growth of the plnts. These different points of view my influene ompost mngement, nd thus the qulity of the finl produt. To ensure long-term sles, omposts should e of high (miro-)iologil qulity, without hrm to the environment nd should enhne plnt vigor nd helth. Tody, vegetle growers inresingly require tht omposts not only hve no negtive influene on plnt growth, ut lso improve plnt helth nd redue disese. Compost influenes plnt growth nd helth indiretly vi the growing onditions (y providing nutrients, espeilly miro nutrients nd y improving soil onditions nd wter retention pity). Composts re not inert mterils; they re rriers of living orgnisms. If the fermenttion is orretly mnged, pthogens re killed during the het period [1, 3]. At the sme time, ntgonists develop during mturtion of the ompost. Therefore, omposts n redue the inidene of vrious plnt diseses [4, 6, 8]. If we lso onsider the positive effet of qulity ompost on soil struture, soil erosion nd wter pity, it is ovious tht n effiient ompost mngement ould inrese nd mintin soil fertility. Not ll omposts re equl Not ll omposts hve the sme pity to protet plnts ginst diseses. Wheres some omposts for exmple did not protet ress ginst Pythium ultimum, other omposts lmost fully suppressed this disese (fig. 1). Loss of the suppressive effet of ompost fter het tretment (one dy t 9 C, fig. 1) indites tht disese suppression might e linked with the miroiologil tivity of the ompost, lthough physiohemil nd iologil properties of omposts ould lso influene suppression pity [2]. I. Session 3 Pper 2 Fuhs, Lri 157

I Interntionl Conferene Septemer 15th 17th 24, León - Spin Fig. 1. Potentil of two omposts to protet ress ginst Pythium ultimum in omprison with untreted nd het treted (one dy t 9 C). The two omposts ome from the sme industril omposting plnt. Different diseses ret differently to ompost. While lmost ll omposts tested protet uumer plnts ginst Pythium ultimum (fig. 2), only some of them hve the pity to protet sili ginst Rhizotoni solni (fig. 3). We ssume generl protetion mehnism for Pythium ultimum nd speifi mehnism in the se of Rhizotoni solni [8]. Influene of ompost qulity on its enefiil effets In our oservtions, we found some ftors orrelted with disese suppressiveness. Amongst others, the omposition nd the mturity of omposts influene the potentil for plnt disese suppression, nd our experiments (dt not presented here) onfirm the results of Tuitert et l. [9]. In ddition, the mngement of the omposting proesses, in prtiulr the oxygen supply, seems to e the most importnt ftor ffeting ompost qulity. This is lso of mjor importne in ompost storge (dt not pulished). Compost qulity is not stle, if it is stored the wrong wy; ompost is living, nd it n lso die! AGood qulity ompost n eome toxi for the plnt in few weeks, if it is not treted orretly, for exmple if its ertion is too poor. So, ompost qulity is the result of reful mngement throughout the prodution hin, from olletion of the rw mteril to storge nd pplition of the finl produt. I. Session 3 Pper 2 Fuhs, Lri 158

I Interntionl Conferene Septemer 15th 17th 24, León - Spin 14 12 plnt 1 plnt 2 plnt 3 plnt 4 Plnt 5 1 Protetion [%] 8 6 4 2-2 16 18 12 29 4 56 8 38 12 13 26 26 1 12 12 12 12 17 Durtion of omposting [weeks].25 g P. ultimum / liter 1 g P. ultimum / liter Fig. 2. Cpity of different omposts to protet uumer ginst Pythium ultimum. Plnt survivl ws ssessed 2 weeks fter sowing. Pythium ultimum inoulum: 7 dys old ulture on utolved sorghum grins. 14 12 1 8 plnt 1 plnt 2 plnt 3 plnt 4 Plnt 5 4 units R. solni / pot 16 units R. solni / pot Protetion [%] 6 4 2-2 16 18 12 29 4 56 8 8 38 12 13 26 26 12 12 12 12 17 17-4 -6 Durtion of omposting [weeks] Fig. 3. Cpity of different omposts to protet sili ginst Rhizotoni solni. Protetion: redution of plnts dying, ssessed 3 weeks fter sowing. Rhizotoni solni inoulum: 14 dys old ulture on utolved sorghum grins. I. Session 3 Pper 2 Fuhs, Lri 159

I Interntionl Conferene Septemer 15th 17th 24, León - Spin Qulity ompost s plnt protetion gent in prtie The pity of qulity ompost to protet plnts ginst diseses is not sientifi uriosity, ut n hve gret signifine in prtie, where it n solve serious phytopthologil prolems. Compost for sfe sprout prodution Sprouts re produed on thin lyer of pet sustrte, nd fter sprouting pked in rdord oxes with ellophne film windows, in whih they hve to mintin their freshness for some dys in the shop (fig. 4). The high humidity in the pkge is very fvourle for the growth of mould fungi, whih develop esily nd quikly in suh n environment, where the miroiologilly inert pet nnot suppress mould growth. Infeted sprouts hve to e disrded, using importnt losses. Adding qulity ompost (3% volume of sustrte volume) solved this prolem very effiiently. The ompost miroorgnisms stilised the environment surrounding the sprouts nd prevented development of moulds. Fig. 4. The living onditions of sprouts re highly fvourle for mould invsion, if pure pet sustrte is used. By dding 3 % of qulity ompost to the pet, the system n e miroiologilly stilised, nd mould growth is suppressed.treted (one dy t 9 C). The two omposts ome from the sme industril ompost plnt. Qulity ompost in orgni ulture sustrte Industrilly used pet sustrtes re miroiologilly intive. There, very smll quntity of pthogen inoulums is suffiient to get high disese inidene (fig. 5). In these ses, dding qulity ompost n effiiently protet plnt (fig. 3). The ddition of ompost stilizes the sustrte miroiologilly, thus reduing the estlishment of pthogens. I. Session 3 Pper 2 Fuhs, Lri 16

I Interntionl Conferene Septemer 15th 17th 24, León - Spin 1 g. P. ultimum / litre sustrte:.5 1 2 4 Plnt survivl [%] 8 6 4 2 d d d d pet sustrte 2/3 pet sustrte + 1/3 ompost 1/3 pet sustrte + 2/3 ompost ompost Fig. 5. Influene of ompost on the inidene of uumer dmping off, usl gent Pythium ultimum, in pet sustrte. Plnt survivl ws ssessed 2 weeks fter sowing. Pythium ultimum inoulum: 7 dys old ulture on utolved sorghum grins. Men of three independent experiments with 6 pots per replite nd 4 uumer seeds per pot. Columns with the sme letter do not differ signifintly t P=.5 (Multiple t-test), ompring eh men with eh other men onsiders one experiment s replite. Qulity ompost for integrted soil steming Soil steming is very effiient nd rdil mesure to eliminte soil orne plnt pthogens, miro-orgnisms nd weed seeds. It is used frequently in vegetle prodution in the field nd the greenhouse. Beuse of its non-seletivity, it destroys the whole omplex of flor nd fun in the soil, irrespetive whether orgnisms re enefiil or hrmful. Sine soils re iologilly empty fter steming, they re very suseptile to miroil oloniztion. Prolemti is lso the uildup of phytotoxi ompounds in the soil, for exmple nitrite, euse of degrdtion of ded iomss fter the soil tretment. Soil from vegetle field ws stemed for 6 hours t 1 C. When ompost with ontrolled high iologil tivity ws dded to the stemed soil during the ooling proess (when its temperture rehed 4 C), the tivity of the ompost miroorgnisms drstilly redued the prolems used y steming. Alredy few hours fter steming, the nitrite level in the soil ws stilized (Fig. 6). Tomto seedlings whih were trnsplnted into the tivted soil one dy fter steming developed vigorously nd without ny symptoms of phytotoxiity (Fig. 7). Even the very sensitive lm's lettue, sown 24 hours fter steming, grew helthy nd vigorously (Fig. 7). I. Session 3 Pper 2 Fuhs, Lri 161

I Interntionl Conferene Septemer 15th 17th 24, León - Spin 3 25 without ompost with 1% ompost Nitrite [ppm in extrt 2:1] 2 15 1 5 5 1 15 2 25 3 35 4 Dy fter soil steming Fig. 6. Influene of ompost on the development of the nitrite level in the soil fter steming. Compost ws dded to the soil fter steming. Eh vlue is the men of three independent experiments. Disese inidene on uumer sown in stemed soil without ompost ws high even with smll inoulum quntities of Pythium ultimum. However, the ddition of 1% of ompost signifintly redued plnt deth. Five to ten times more inoulum would hve een neessry to otin pproximtively the sme disese inidene in the soil with ompost s in the soil without ompost (Fig. 8). Fig. 7. Influene of ompost on the phytotoxiity of tomto seedlings () nd of lm s lettue ().. I. Session 3 Pper 2 Fuhs, Lri 162

I Interntionl Conferene Septemer 15th 17th 24, León - Spin [g P. ultimum /liter soil]: 1 2 4 8 h gh Fig. 8. Plnt weight [g/pot] 3 2 1 ef d d f d d non treted stemed stemed + ompost Influene of ompost on the reeptivity to Pythium ultimum using dmping off on uumer in the stemed soil. Compost ws dded to the soil fter steming. Eh vlue is the men of three independent experiments with six pots nd four uumer seed per pot. Columns with the sme letter do not differ signifintly t P=.5 (Multiple t-test), ompring eh men with eh other men onsiders one experiment s replite. fg e Qulity ompost for improvement of soil fertility in the field For the ssessment of long term effets of ompost on plnt disese, fields were divided into two plots. On one hlf of the field ompost ws pplied eh yer (1 tons dry weight per h), while the other hlf ws used s hek. After five yers, soil smples were tken on the different field plots. The disese reeptivity of the soils for Pythium ultimum ws lower in the plots with ompost ompred to those without ompost (fig. 9). The sme effet ws lso found for Rhizotoni solni. Suppressive effets of ompost ould still e lerly oserved one yer fter ompost pplition We lso found negtive orreltion etween more intensive soil ultivtion nd disese reeptivity (dt not shown). This is no surprise: the iologil equilirium is more distured in intensively worked fields, nd therefore the positive influene of ompost eme more distint. I. Session 3 Pper 2 Fuhs, Lri 163

I Interntionl Conferene Septemer 15th 17th 24, León - Spin 1 g. P. ultimum / litre sustrte: 1 2 4 8 16 Plnt survivl [%] 8 6 4 2 soil without ompost soil with ompost (lst mendment 1 yer go) soil with ompost (lst mendment 1 week go) Fig. 9. Influene of qulity ompost mendments on the reeptivity of soil to Pythium ultimum, pthogeni gent of uumer dmping off. Twenty tons of ompost were given eh yer to one hlf of vegetle field in Fehrltorf (CH), on the other hlf of the field no ompost ws pplied. Soil smples were tken fter five yers efore nd fter mendment with new ompost. Plnt survivl ws ssessed 2 weeks fter sowing. Pythium ultimum inoulum in lortory tests: 7 dys old ulture on utolved sorghum grins. Eh vlue is the men of three independent experiments with 6 pots with 4 uumer seeds per pot. Columns with the sme letter do not differ signifintly t P=.5 (Multiple t-test), ompring eh men with eh other men onsiders one experiment s repetition. Qulity ompost nd indued resistne The effets of qulity omposts dded to soil re not restrited to suppression of soil orne disese. They lso redue the development of folir pthogens suh s Blumeri (Erysiphe) grminis f.sp. hordei, the usl gent of rley powdery mildew (fig. 1). The potentil to indue disese resistne in rley plnts, vried onsiderly from ompost to ompost, depending on their iologil qulity (fig. 1). No orreltion etween nitrogen ontent or nitrogen vilility of the omposts nd pthogen suppression ws found. I. Session 3 Pper 2 Fuhs, Lri 164

I Interntionl Conferene Septemer 15th 17th 24, León - Spin 1 8 1% ompost 3% ompost 5% ompost 6 Protetion [%] 4 2 d * d * d * e * ompost 1 ompost 2 ompost 3 ompost 4-2 Fig. 1. Influene of omposts on the inidene of the rley powdery mildew, used y Blumeri grminis f.sp. hordei. Composts from different thes were dded to the sustrtes (Brill No. 5, Ger. BRILL, D- Georgsdorf) efore sowing (1, 3 or 5% of sustrte volume). After ten dys, the first leves of rley were inoulted with B. grminis onidi. Protetion: redution on the olony units formed on the leves one week fter inoultion. Eh vlue is the men of three independent experiments with 4 pots with 1 rley plnts per pot. Columns with the sme letter do not differ signifintly t P=.5 (Multiple t- test), ompring eh men with eh other men onsiders one experiment s repetition. Columns with * do not differ signifintly t P=.5 ompred to the hek Qulity insurne: the key to suess Although not ll mehnisms nd ftors tht influene iologil ompost qulity re known s yet, our knowledge is rod enough to llow the prodution of good qulity ompost. The three most importnt ftors to ontrol during fermenttion re the moisture of the mteril, the ir omposition nd temperture. At the end of mturtion, the following qulity prmeters hve to e nlyzed: ph, slt ontent, mmonium, nitrite nd nitrte ontent. In ddition, we propose to rry out plnt tests [5] for two resons: (i) plnts ret to ompost qulity s whole, nd so hidden prolems n pper; (ii) plnts ret during the entire test period (out two weeks), thus the evolution of some prmeters n e oserved. This is prtiulrly importnt for nitrogen vilility. For omposts used in hortiulturl nd vegetles prodution, testing their disese suppressive potentil with the Rhizotoni nd Pythium tests is reommended. With this informtion, it is possile to hoose the most pproprite ompost for eh utiliztion. The ASCP Guidelines 21 Qulity riteri for omposts nd digesttes from iodegrdle wste mngement (pulished y the Assoition of Swiss Compost Plnts (ASCP) in ollortion with the Swiss Biogs Forum) provides support for ompost produers nd ompost users in this respet [7]. I. Session 3 Pper 2 Fuhs, Lri 165

I Interntionl Conferene Septemer 15th 17th 24, León - Spin Conlusions Qulity ompost n hve positive effet on soil fertility nd plnt growth nd helth. This positive effet is not only oservle in the lortory, ut lso y growers. Phytopthologil prolems ould e solved with the use of ompost. Durle suess n only e otined if qulity mngement is resolutely followed. Further reserh is needed to optimize the qulity mngement of ompost prodution nd utiliztion. For exmple, very little is known out the long-term effet of the different omposts on soil fertility nd disese reeptivity. Referenes [1] Bollen, G. J. (1993). Ftors involved in intivtion of plnt pthogens during omposting of rop residues. In Siene nd Engineering of Composting: Design, Environmentl, Miroiologil nd Utiliztion Aspets., edited y H. M. Keener. Worthington, Ohio: Renissne pulitions. [2] Boulter, J.I.; Bolnd, G.J.; Trevors, J.T. (2). Compost: A study of the development proess nd endprodut potentil for suppression of turfgrss disese. Word Journl of Miroiology & Biotehnology 16: (2): 115-134. [3] Engeli, H.; Edelmnn, W; Fuhs, J.; Rottermnn, K. (1993). Survivl of plnt pthogens nd weed seeds during neroi digestion. Wter Siene nd Tehnology 27 (2): 69-76. [4] Fuhs, J. (1995). Effet of ompost mendments on the reeptivity of soils to diseses: first results. OT: Influene d'mendements de omposts sur l reeptivite de sols ux mldies: premiers resultts. Revue Suisse de Vitiulture, d'aroriulture et d'hortiulture 27 (4) [5] Fuhs, J.G.; Bieri, M. (2). Neue Pflnzentests, um die Kompostqulität zu hrkterisieren. Agrrforshung 7: 314-319. [6] Fuhs, J.G. (22). Prtil use of qulity ompost for plnt helth nd vitlity improvement. In Miroiology of Composting, edited y S. Klmmer. Berlin Heiselerg: Springer-Verlg. [7] Fuhs, J.G.; Glli, U.P.; Fisher, C.M.; Shleiss, K.E. (23). Qulity egins t home: the swiss strtegy to improve the imge of ompost. Offiil Proeedings of the Environment Eonomy Equlity, 1th-13th June 23, Pington, Tory, UK, CIWM ed. Tuesdy Workshop Session A: Pper 4: 1-4. [8] Hoitink, H. A. J., A.; Stone, G.; Hn, D.Y. (1997). Suppression of plnt diseses y omposts. HortSiene 32:184-187. [9] Tuitert, G.; Szzeh, M.; Bollen, G.J. (1998). Suppression of Rhizotoni solni in potting mixtures mended with ompost mde from orgni household wste. Phytopthology 88 (8):764-773. I. Session 3 Pper 2 Fuhs, Lri 166