CALIBRATION AND TEST OF THE CROPGRO-DRY BEAN MODEL FOR EDAPHOCLIMATIC CONDITIONS IN THE SAVANAS OF CENTRAL BRAZIL 1

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1 73 CALIBRATION AND TEST OF THE CROPGRO-DRY BEAN MODEL FOR EDAPHOCLIMATIC CONDITIONS IN THE SAVANAS OF CENTRAL BRAZIL Elz Jcqueline Leite Meireles,5 *; Antonio Roerto Pereir 3,5 ; Pulo Cesr Sentelhs 3 ; Luis Fernndo Stone,5 ; Frncisco José Pfeilsticker Zimmermnn Emrp Cfé, Edifício Sede d Emrp - PqEB, Finl d Av. W3 Norte - sl 3 - CEP: Brsíli, DF. 3 Depto. de Ciêncis Exts, USP/ESALQ, C.P. 9 - CEP:3-9 - Pircic, SP. Emrp Arroz e Feijão, C. P CEP: Snto Antônio de Goiás, GO. 5 CNPq Fellow. *Corresponding uthor <jcqueline.meireles@emrp.r> ABSTRACT: Simultion models re importnt tools for the nlysis of cultivted systems to estimte the performnce of crops in different environments. The CROPGRO- model (DSSAT) ws clirted nd vlidted using Crioc en (Phseolus vulgris L.) to estimte yield nd the development of the crop, sown in three row spcings (.,.5, nd. m) nd two fertiliztion rtes (3 nd 5 kg h - of -3- N-P-K), in Snto Antônio de Goiás, GO, Brzil. To clirte the model comintion of the genetic coefficients tht chrcterize the phenology nd morphology of the dry en crop ws used to otin the est possile fit etween predicted nd oserved nthesis nd physiologicl mturity dtes, lef re index (LAI), totl dry mtter (TDM), yield components, nd grin yield for the. m row spcing. To test the model the experimentl records of the. nd.5 m row spcings were used. In oth, clirtion nd test, the performnce of the model ws evluted plotting oserved nd predicted vlues of LAI nd TDM versus time, using the r, nd the greement index (d) s sttisticl criteri. In reltion to yield nd yield components the percent difference etween the oserved nd predicted dt ws clculted. The model ppered to e dequte to simulte phenology, grin yield nd yield components for the Crioc en cultivr, relted to different levels of fertiliztion nd row spcing, either during clirtion or the testing phse. During the test, the grin yield ws overestimted y less thn 5.%, indicting potentil use for the clirted model in ssessing climtic risks in this region. Key words: DSSAT, dry en, simultion CALIBRAÇÃO E TESTE DO MODELO CROPGRO-DRY BEAN PARA AS CONDIÇÕES EDAFOCLIMÁTICAS DO BRASIL CENTRAL RESUMO: Modelos de simulção são importntes ferrments n nálise de sistems cultivdos pr estimr performnce d cultur em diferentes mientes. O modelo CROPGRO- foi clirdo e testdo, utilizndose o cultivr Crioc pr estimr produtividde e o desenvolvimento do feijoeiro (Phseolus vulgris L.) so três espçmentos (,,,5 e, m) e dus doses de dução (3 e 5 kg h - de -3- de N-P- K), em Snto Antônio de Goiás, GO. A clirção consistiu n modificção dos coeficientes genéticos crcterísticos d fenologi e morfologi do feijoeiro, visndo oter os melhores justes possíveis entre os ddos simuldos e os oservdos cmpo ds dts de ntese e mturção fisiológic, índice de áre folir (IAF), mss de mtéri sec totl (MMST), componentes de produção e produtividde de grãos pr o espçmento de, m. Pr o teste do modelo form utilizdos os ddos experimentis correspondentes os espçmentos de, e,5 m. Em mos, clirção e teste, ferição d performnce do modelo foi efetud plotndo-se os vlores oservdos e simuldos do IAF e MMST o longo do tempo (dis pós semedur), e utilizndo-se o r e o índice de concordânci (d) como critério esttístico. Pr produtividde de grãos e componentes de produção determinou-se diferenç percentul entre os vlores oservdos e simuldos. O modelo simulou stisftorimente fenologi, produtividde de grãos e os componentes de produção, pr s diferentes doses de dução e espçmentos, tnto n fse de clirção como n de teste. Durnte o teste, produtividde de grãos foi superestimd, no máximo, em 5,%, indicndo o potencil do modelo clirdo em futur nálise de riscos climáticos. Plvrs-chve: DSSAT, feijoeiro, simulção INTRODUCTION The CROPGRO-Dry Ben model, which is prt of the DSSAT system (Decision Support System for Agrotechnology Trnsfer) nd of the IBSNAT project (Interntionl Benchmrk Sites Network for Agrotechnology Trnsfer), is composed of deterministic nd mechnistic model tht simultes the durtion of vegettive nd reproductive stges, ccumultion of iomss, nd grin yield for specific cultivr ssocited Prt of the PhD Thesis of the first uthor, presented to USP/ESALQ - Pircic, SP, Brzil. Scienti Agricol, v.59, n., p.73-79, out./dez.

2 7 Meireles et l. to mngement prctices, soil nd climte conditions (Hoogenoom et l., 99). Cultivrs re represented y group of genetic coefficients derived from clirtions using dt from field experiments. These coefficients descrie the genotype chrcteristics in response to soil nd climte conditions, ffecting phenology, ccumultion of iomss nd prtitioning of ssimiltes. To simulte crop phenology, CROPGRO defines 3 stges, ech one set when phototherml ccumultor is reched (Jones et l., 99). The limits of these phototherml ccumultors re estlished through the genetic coefficients. Biomss is divided mong the plnt orgns nd its ccumultion is regulted y the photosynthesis process, which depends on light interception, photoperiod, temperture, nd wter nd nitrogen supply (Fri et l., 997). Clirtions nd tests of simultion models, tht re prt of the DSSAT, were performed for vrious crops in Brzil. For the dry en, for instnce, Fri et l. (997) clirted the BEANGRO model for the conditions of Londrin, PR - Brzil, testing its performnce under severl environmentl conditions. Although some modifictions were necessry, results indicted tht the model is dequte to estimte phenology nd grin yield for two cultivrs for severl sowing dtes nd moisture regimes, llowing its use for climtic risk nd technicl nd economicl viility studies of this crop under rid nd irrigted conditions. Bstos (999) dpted the CROPGRO model to simulte the cowpe crop (CROPGRO-cowpe) under severl mngement prctices in Piuí, Brzil, for severl loctions nd moisture conditions, in order to develop informtion out irrigtion mngement tht offers higher net return. This work hd s purpose to clirte nd test the CROPGRO-Dry Ben model for Crioc dry en, grown under severl row spcings nd fertilizer rtes, in Snto Antônio de Goiás, GO, Brzil, iming t its lter use to nlyze climtic risk for dry en growing in the Cerrdo (Svnnh-like) Goino. MATERIAL AND METHODS The CROPGRO-Dry Ben model, version., developed y Hoogenoom et l (99) requires genetic prmeters of the cultivr s well s detiled informtion on soil, climte nd crop mngement. Three files chrcterize input dt of the crop ccording to the following description: () file.eco, which chrcterizes the ecotype nd contins genetic ttriutes tht discriminte cultivrs of determinte nd indeterminte growth; () file.spe, tht chrcterizes species nd contins coefficients tht define the sic composition of tissues nd descrie the photosynthesis process, respirtion, nitrogen ssimiltion, prtition of ssimiltes, senescence, phenology nd growth; (c) file.cul, which contins prticulr informtion on the cultivr such s photoperiod sensitivity, photosynthetic rte, specific lef re, mximum grin weight, the mximum re of Trifolium, verge numer of grins per pod, numer of dys etween emergence nd first flower, etween first flower nd first pod, first flower nd first grin, first grin nd physiologicl mturity, nd etween first flower nd the end of lef expnsion. Wether dt, such s mximum nd minimum ir temperture, rinfll nd solr rdition, on dily sis, re in the climte files (STATION.WTH nd STATION. CLI). Soil dt such s ulk density, wter sturtion, field wter cpcity, permnent wilting point, soil ledo, grnolometry nlyses, orgnic C, texture, ph, mong others, re in the SOIL.SOL file. The X file defines ll the informtion on crop mngement (irrigtion, fertilizers, incorportion of residues, crop rottion, nd plnting dte). This work used climtologic dily series of mximum nd minimum ir temperture, rinfll nd numer of sunshine hours dt from 97 to 99 otined t Emrp Centro Ncionl de Pesquis de Arroz e Feijão (CNPAF), s well s informtion on physicl, chemicl nd wter chrcteristics of the locl soil, clssified s n Oxisol, to generte climte nd soil files used in the simultions. Phenology, grin yield nd yield component dt used in the clirtion nd test of the model were otined y Stone & Pereir (99; 99) from field experiment in which the three row spcings were evluted (E=. m; E=.5 m; nd E3=. m) nd two fertiliztion effects (A = 3 kg h - ; nd A = 5 kg h - of the formul -3-) for the Crioc en cultivr yield (Meireles, ). In this experiment, sowing ws on July st, 99 under center pivot t Emrp - CNPAF (Fzend Cpivr), in Snto Antônio de Goiás, GO, Brzil ( S; 9 o 7 W; 3 m). Stone & Pereir (99; 99) mnged the irrigtion in such wy tht the wter potentil in the soil, mesured t.5 m depth, ws not higher thn.3 MP, s recommended y Stone t l. (99). The clirtion of the CROPGRO-Dry Ben model consisted of the modifiction of numer of genetic coefficients such s the numer of dys etween emergence nd first flower, first flower nd first pod, first flower nd first grin, first grin nd physiologicl mturity, nd etween first flower nd the end of lef expnsion, mximum photosynthetic rte, specific lef re, mximum re of Trifolium, mximum grin weight, verge numer of grins per pod to chieve the est possile djustments etween predicted nd oserved dt ccording to the method proposed y Boote (99). First, flowering nd physiologicl mturity dtes were djusted, ltering the genetic coefficients relted to the crop phenology in wy tht predicted nd oserved vlues were closer to the experimentl vlues. Scienti Agricol, v.59, n., p.73-79, out./dez.

3 75 Susequently, lef re index, dry mtter yield, one grin weight, numer of grins per pod, numer of seeds per m², nd grin yield djustments were mde. At this stge, sequentil vlues were ttriuted to plnt prmeters, nd the model ws run severl times until predicted vlues were closer to those oserved for the row spcing of. m nd the two fertiliztions. The estimtes of the numer of dys to first flower, pod, nd grin s well s to physiologicl mturity in the simultions were sed on the concept of physiologicl dy (Boote et l., 99). The reltionship etween the physiologicl dy (PD) nd the clendr dy (Dy) is defined y the eqution: PD/Dy = f(t). f(p). f(w) () where f(t) is the growth restriction fctor due to ir temperture, f(p) is the growth restriction fctor due to photoperiod nd f(w) is the growth restriction fctor due to wter stress, ll three undimensionl. For optiml temperture, photoperiod, nd soil wter f(t), f(p), nd f(w) re = nd in this cse the physiologicl dy equls the clendr dy; for other conditions PD Dy. Eqution () is sed on sl temperture (T), optiml tempertures (To nd To ), nd limit temperture (Tl) vlues for ech phse (Tle ). In this work, f(p) nd f(w) were considered to e one, since the dry en crop ws not ffected y photoperiod, nd there ws no wter restriction during simultion. In the test, the vlues predicted y the clirted model were compred to those mesured, not used in the clirtion (row spcings of. m nd.5 m) s suggested y Jones et l. (97) nd Hoogenoom et l. (99). This comprison ws relted to nthesis nd physiologicl mturity dtes, lef re index, totl dry mtter, yield components, nd yield. The performnce of the model ws evluted ccording to grphic nd sttisticl methods, plotting oserved nd predicted vlues of lef re index (LAI) nd totl dry mtter (TDM) versus time. As sttisticl criteri, the regression nlysis - which shows the precision of the estimtes through coefficient of determintion (r²) - nd the index of greement (d) (Wilmott et l., 95) - which indictes the ccurcy of estimtes in reltion to oserved vlues - were used, Tle - Bsl temperture (T), optiml tempertures (To e To ) nd limit temperture (Tl) for the dry en crop cycle ccording to the CROPGRO-Dry Ben model, v... Stge T To To Tl C Vegettive Before reproductive stge After reproductive stge Source: Hoogenoom et l. (99). Scienti Agricol, v.59, n., p.73-79, out./dez. rnging from zero which indictes null result to one which indictes perfect ccurcy. The d index ws determined s follows: d = - [(Σ (P i O i ) / Σ ( P i - O + O i - O ) ] () where: O i = mesured vlue of LAI nd TDM, P i = estimted vlue of LAI nd TDM, O = verge of mesured vlues of LAI nd TDM, nd i = numer of oservtions. Anlysis of vrince ws run for predicted nd oserved LAI nd TDM vlues of the dry en crop for ll row spcings nd fertiliztions. For grin yield nd yield components the percent difference etween the oserved nd predicted dt ws clculted. The model still does not consider the effects of pests nd diseses, which ffect the experimentl results. In order to minimize this prolem, the experimentl vlues re shown s verges nd stndrd devitions. The simultion in the intervl of stndrd devition ws considered good. RESULTS AND DISCUSSION Clirtion of the model The comintion of the genetic coefficients tht etter predicted phenology nd morphology of Crioc en is shown in Tle. With these coefficients, good fit etween the nthesis ( dys fter sowing, DAS) nd the physiologicl mturity dtes ( DAS) predicted nd oserved in the field for the two fertiliztion rtes. This is regulted y genetic chrcteristics nd ffected y temperture. There ws no effect of fertiliztion rte. These results re different from those of Mrtins et l. (99) in the utumn-winter seson in the region of Lvrs, MG, Brzil, where Crioc en needed DAS to rech nthesis nd DAS to rech physiologicl mturity. In Lvrs, there ws n extension of the crop cycle due to colder tempertures s compred to Snto Antônio de Goiás. The simultion of TDM ws good with good prediction, s well s n lmost perfect ccurcy of TDM estimtes in reltion to the oserved vlues, d =.99 (Figure ) nd d =.9 (Figure ). A etter djustment for fertiliztion A (Figure ) during lmost the whole cycle. For fertiliztion A (Figure ), the model underestimted until the physiologicl mturity (7 DAS) nd n overestimted therefter. A similr sitution ws descried y White et l. (995) in the BEANGRO model pplied to the Crioc en cultivr with overestimtes during the grin filling period. Compring the predicted nd oserved LAI nd their respective stndrd devitions, the djustments were stisfctory, with r =.9 for fertiliztion A nd. for A. Although the ccurcy of the estimtes of LAI, expressed y r, ws lower for the two fertiliztion, rtes the ccurcy of the estimtes of LAI in reltion to the oserved vlues rnyed from.9 to.95 for the

4 7 Meireles et l. smller nd lrger fertiliztion, rtes respectively. There ws n underestimte until pproximtely 3 DAS, comprehending the eginning of flowering, with susequent overestimte (Figures nd ). The overestimtes my e relted to pests nd diseses, not considered y the model. The predicted mximum LAI ws out % higher thn the oserved (3.7) with dely of 3 dys for fertiliztion A. In reltion to A, the predicted mximum LAI occurred dys in dvnce, eing out 7% smller (5.9). Adequte wter, solr energy nd nutrient conditions fvored the most intense vegettive growth of the crop, resulting in higher LAI for the lrger fertiliztion. High mximum LAI ws lso otined y Urchei (99) with cultivr Aporé under no-till system (5.3) nd in conventionl till system (.9) out 5 dys fter emergence, in the flowering stge, in the region of Sendor Cnedo, GO, Brzil. Using F test, no differences etween the predicted nd oserved LAI nd TDM vlues for dry en, row spcing of. m nd fertiliztions A nd A, were. Yield prediction ws good found with difference of +,% for fertiliztion A (3 kg h - os./3 kg h - sim.), nd +7.% for fertiliztion A ( kg h - os./377 kg h - sim.). The numer of grins per pod incresed with the fertiliztion rte (A =.9; A = 5.), which ws lso reported y Grrido (99), nd well predicted in our simultion (Tle 3). However, the mss of grins (M) ws reduced with the increse in fertiliztion rte (A =.3 x - kg/ grins; A =.9 x - kg/ grins), contrry to the findings of Grrido (99), positive liner reltionship etween N rte nd M, where ws found with increses of 3. x -5 kg kg - pplied N. Tle - Modified genetic coefficients resulted from the clirtion of the CROPGRO-Dry Ben model for the Crioc dry en cultivr, row spcing of. m, nd fertiliztion rtes of 3 nd 5 kg h -, in Snto Antônio de Goiás, GO, Brzil. Genetic coefficients CROPGRO- Dry Ben Physiologicl dy (PD) it corresponds to the clendr dy when in optiml conditions for plnt development. Experimentl vlues, Emrp Centro Ncionl de Pesquis de Arroz e Feijão, Snto Antônio de Goiás, GO, Brzil. 3 Portes, T. A. Personl comuniction. Universidde Federl de Goiás, Goiâni, GO, Brzil, 999. Genetic coefficient file gcrules.fle of DSSAT 3.5. Modified vlues Fertiliztion kg h Numer of dys etween emergency nd first flowe (PD ) Numer of dys etween first flower nd first pod (PD) Numer of dys etween first flower nd first grin (PD) Numer of dys etween first grin nd physiologicl mturity (PD) Numer of dys etween first flower nd the end of lef expnsio (PD) Photosynthetic mximum rte ( - kg CO m - s - ).9.. Specific lef re in mientl growth conditions (m kg - ) Mximum re of trifolium ( - m ) 33 Mximum grin weight ( - kg) Averge numer of grins per pod r =.99 d=.99 r =.97 d= Figure - Oserved nd predicted totl dry mtter (TDM) of the dry en crop, Crioc cultivr, row spcing of. m, nd fertiliztion of 3 () nd 5 kg h - (), t Snto Antônio de Goiás, GO, Brzil. The mplitude of the verticl lines corresponds to stndrd Scienti Agricol, v.59, n., p.73-79, out./dez.

5 77 Testing the model When testing the clirted model for row spcings E nd E, no differences etween the predicted nd oserved dt t the nthesis ( DAS) for the two fertiliztions were found nd the dte of the predicted physiologicl mturity ( DAS) differed only y one dy in reltion to tht oserved for E nd A. These results show good performnce of the CROPGRO-Dry Ben model when simulting the dry en phenology. TDM ws underestimted during the whole cycle for the row spcing E with fertiliztion A (Figure 3). There ws difference in phse etween the predicted nd oserved vlues. Nonetheless, r =.9 nd d =.9 were stisfctory. In reltion to the fertiliztion rte A, the simultion ws little etter ecuse the stndrd devitions of the oserved vlues were lrger, including the predicted curve during most prt of the cycle, resulting r =.9 nd d =.9 (Figure 3). In reltion to the row spcing E, the simultion ws etter with two fertiliztions, resulting in r =.97 nd.95, nd d =.99 nd.9 (Figure ). At the end of the cycle, the mximum vlues of TDM were overestimted for fertiliztion A. Overestimtes of TDM were lso otined y White et l. (995) with the BEANGRO model. LAI, ws underestimted during the whole cycle for tretment E A. However, r ws.9, indicting stisfctory precision nd d ws.93, expressing good ccurcy etween the predicted nd oserved dt (Figure 5). Concerning tretment E A, the overestimte ws until 55 DAS, including the period of flowering, with susequent overestimte until the end of the cycle (Figure 5). Although the coefficient of determintion ws lower (r =.7), the index of greement ws stisfctory (d =.9). These differences my e relted to pests nd diseses tht the model does not consider s well s to the sptil vriility of the experimentl dt. In the cse of tretment E A, the underestimte occurred during the vegettive stge nd prt of the flowering stge, tht is, until pproximtely 5 DAS, ut fter this stge there ws n overestimte until the end of the cycle (Figure ). A similr sitution occurred for tretment E A, with n inversion next to DAS, t the eginning of flowering (Figure ). In reltion to the coefficients of determintion (Figure ), the ccurcy of estimtes were reduced with increses in fertiliztion, s well s the index of greement (d E A =.99; d =.9), showing lower ccurcy of the E A estimtes of LAI in reltion to the oserved vlues. The nrrower row spcing (E) showed higher mximum LAI, (.) for fertiliztion A, nd.7 for A, row spcing E with.7 for fertiliztion A nd 3. for A. F test, reveled no differences etween the predicted nd oserved LAI nd TDM vlues for row spcings E nd E nd fertiliztion A e A were oserved. The predicted yields of grins were higher thn those in field under ll conditions (Tle ). Differences of +.9% in tretment E A nd of +.7% for tretment E A were oserved. The difference ws of +.% in tretment E A wheres in tretment E A it incresed y + 5.%. Similr results were reported y White et l. (995) with the BEANGRO model, lthough with higher overestimtes for the sme Crioc en cultivr. Tle 3 - Oserved nd predicted yield nd yield components of the dry en crop, Crioc cultivr, row spcing of. m, nd fertiliztion of 3 e 5 kg h -, in the clirtion phse of the model, for Snto Antônio de Goiás, GO, Brzil. Component Difference (%) = [(Predicted Oserved) / Oserved]x LAI (m m - ) r =.9 d=.9 Scienti Agricol, v.59, n., p.73-79, out./dez. Fertiliztion (kg h - ) 3 5 Predicted Oserved Dif (%) Predicted Oserved Dif (%) Yield (kg h - ) Numer of grin/pod Weight grins (kg).3 x -.3 x -.9 x -.9 x Figure - Oserved nd predicted lef re index (LAI) of the dry en crop, Crioc cultivr, row spcing of. m, nd fertiliztion of 3 () nd 5 kg h - (), t Snto Antônio de Goiás, GO, Brzil. The mplitude of the verticl lines corresponds to stndrd LAI (m m - ) r =. d=.95

6 7 Meireles et l. r =.9 d= r =.9 d= Figure 3 - Oserved nd predicted totl dry mtter (TDM) of the dry en crop, Crioc cultivr, row spcing of. m, nd fertiliztion of 3 () nd 5 kg h - (), t Snto Antônio de Goiás, GO, Brzil. The mplitude of the verticl lines corresponds to stndrd Tol dry mtter (kg h - ) Figure - Oserved nd predicted totl dry mtter (TDM) of the dry en crop, Crioc cultivr, row spcing of.5 m, nd fertiliztion of 3 () nd 5 kg h - (), t Snto Antônio de Goiás, GO, Brzil. The mplitude of the verticl lines corresponds to stndrd LAI (m m - ) r =.97 d= r =.9 d=.93 LAI (m m - ) r =.95 d= r =.7 d= Figure 5 - Oserved nd predicted lef re index (LAI) of the dry en crop, Crioc cultivr, row spcing of. m, nd fertiliztion 3 () nd 5 kg h - (), t Snto Antônio de Goiás, GO, Brzil. The mplitude of the verticl lines corresponds to stndrd For numer of grins per pod, the simultions were lmost perfect for ll tretments, except for E A in which the difference ws of +5.% (Tle ). The numer of grins per pod vried little, due to row spcings nd popultions, similr to tht reported y Vlério (99) in the trils mde during the riny seson, drought nd of winter/spring in the region of Lvrs, indicting tht it is yield component little ffected y the environment. For M, lrger differences etween predicted nd oserved vlues were found in tretments E A with +7.5%, nd E A with +.5% (Tle ). M vried little etween the tretments, from.3x - kg/ grins to.x - kg/ grins, result similr to tht otined y Roch (99). The CROPGRO-Dry Ben model, fter clirted nd tested for Crioc dry en, under contrsting row spcings nd fertiliztion rtes in Snto Antônio de Goiás, performed well in predicting phenology, yield components, nd yield, indicting tht it cn e used in ssessing climtic risks for the cultivtion of this crop in the Cerrdo Goino. Scienti Agricol, v.59, n., p.73-79, out./dez.

7 79 LAI (m m - ) r =.93 d=.99 LAI (m m - ) r =. d= Figure - Lef re index (LAI) oserved nd predicted of the dry en crop, Crioc cultivr, spcing.5 m, nd fertiliztion 3 () nd 5 kg h - () t Snto Antônio de Goiás, GO, Brzil. The mplitude of the verticl lines corresponds to ± stndrd Tle - Oserved nd predicted yield nd yield components of the dry en crop, Crioc cultivr, row spcings of. m nd.5 m, nd fertiliztion of 3 e 5 kg h -, for Snto Antônio de Goiás, GO, Brzil. Fertiliztion (kg h - ) Component 3 5 Predicted Oserved Dif (%) / Predicted Oserved Dif (%) Yield (kg h - ) Row spcing. m Row spcing.5 m N of grins per pod Row spcing. m Row spcing.5 m M (kg) Row spcing. m.3x -.x x -.7x -.9 Row spcing.5 m.3x -.3x -.5.x -.5x -.9 Difference(%)=[(Predicted-Oserved)/Oserved]x. REFERENCES BASTOS, E.A. Adptção do modelo CROPGRO pr simulção do crescimento e desenvolvimento do feijão cupi Vign unguicult (L.) Wlp. so diferentes condições hídrics, no Estdo do Piuí. Pircic, p. Tese (Doutordo) - Escol Superior de Agricultur Luiz de Queiroz, Universidde de São Pulo. BOOTE, K.J. Concepts for clirting crop growth models. Crop simultion course. S.l.: s.n., 99, 3p. BOOTE, K.J.; JONES, J.W.; HOOGENBOOM, G. Simultion of crop growth: CROPGRO model. In: PEART, R.M.; CURRY, R.B. (Ed.) Agriculturl systems modeling nd simultion. New York: Mrcel Dekker, 99. p FARIA, R.T. de; OLIVEIRA, D. de; FOLEGATTI, M.V. Simulção d fenologi e produção do feijoeiro pelo modelo BEANGRO. In: CONGRESSO BRASILEIRO DE AGROMETEOROLOGIA,., Pircic, 997. Anis. Pircic: Sociedde Brsileir de Agrometeorologi, 997. p.-. FARIA, R.T. de; FOLEGATTI, M.V.; FRIZZONE, J.A.; SAAD, A.M. Determintion of long-term optiml irrigtion strtegy for dry ens in Prná stte, Brzil. Scienti Agricol, v.5, p.55-, 997. Número especil. GARRIDO, M.A.T. Resposts do feijoeiro às lâmins de águ e dução nitrogend. Lvrs, 99. 5p. Tese (Doutordo) Universidde Federl de Lvrs. HOOGENBOOM, G.; JONES, J.W.; BOOTE, K.J. Modeling growth, development, nd yield of grin legumes using soygro, pnutgro, nd engro: review. Trnsctions of the ASAE, v.35, p.3-55, 99. HOOGENBOOM, G.; WHITE, J.M.; JONES, J.W.; BOOTE, K.J.; BOWEN, W.T.; PICKERING, N.B.; BATCHELOR, W.D. CROPGRO Dry en. In: TSUJI, G.Y.; UEHARA, G.; BALAS, S. (Ed.) Crop models. DSSAT version 3. Honolulu: University of Hwii, 99, p.95-. JONES, J.W.; MISHOE, J.W.; BOOTE, K.J. Introduction to simultion nd modeling. Ginesville: ASPAC Food & Fertilizer Technology Center, 97. 9p. (Technicl Bulletin, ) JONES, J.W.; WHITE, J.W.; BOOTE, K.J.; HOOGENBOOM, G.; PORTER, C.H. Phenology Module - CROPGRO v.3.7 documenttion nd source code listing. Ginesville: University of Florid, 99. p. (Reserch Report, 9-5). Scienti Agricol, v.59, n., p.73-79, out./dez. MARTINS, L.A.; SOUSA, F.F. de; RAMALHO, M.A.P.; ABREU, A.F.B. Vriilidde d tx e d durção do período de cúmulo de mtéri sec nos grãos do feijoeiro (Phseolus vulgris L.) Ciênci e Prátic, v., p.5-7, 99. MEIRELES, E.J.L. Utilizção do modelo CROPGRO dry en n nálise de risco climático d cultur do feijoeiro (Phseolus vulgris L.) n região de cerrdos. Pircic,. 5p. Tese (Doutordo) Escol Superior de Agricultur Luiz de Queiroz, Universidde de São Pulo. ROCHA, J.A.M. Produção do feijoeiro (Phseolus vulgris L.) cultivdo em populções vriáveis qunto o número e o rrnjmento de plnts. Pircic, 99. p. Dissertção (Mestrdo) Escol Superior de Agricultur Luiz de Queiroz, Universidde de São Pulo. STONE, L.F.; PEREIRA, A.L. Sucessão rroz-feijão irrigdos por spersão: efeitos de espçmento entre linhs, dução e cultivres n produtividde e nutrição do feijoeiro. Pesquis Agropecuári Brsileir, v.9, p.5-533, 99. STONE, L.F.; PEREIRA, A.L. Sucessão rroz-feijão irrigdos por spersão: efeitos de espçmento entre linhs, dução e cultivr no crescimento, desenvolvimento rdiculr e consumo d águ do feijoeiro. Pesquis Agropecuári Brsileir, v.9, p , 99. STONE, L.F.; MOREIRA, J.A.A.; SILVA, S.C. d. Efeitos d tensão d águ no solo sore produtividde e crescimento do feijoeiro: I. Produtividde. Pesquis Agropecuári Brsileir, v.3, p.-7, 9. URCHEI, M.A. Efeitos do plntio direto e do prepro convencionl sore lguns triutos físicos de um Ltossolo Vermelho-Escuro rgiloso e no crescimento e desenvolvimento do feijoeiro (Phseolus vulgris L.) so irrigção. Botuctu, 99. 3p. Tese (Doutordo) Universidde Estdul Pulist Júlio de Mesquit Filho. VALÉRIO, C.R. Comportmento de cultivres de feijão tipo Crioc em diferentes populções de plnts e espçmentos entre linhs. Lvrs, 99. 9p. Dissertção (Mestrdo) Universidde Federl de Lvrs. WHITE, J.W.; HOOGENBOOM, G.; JONES, J.W.; BOOTE, K.J. Evlution of the dry en model BEANGRO V. for crop production reserch in tropicl environment. Experimentl Agriculture, v.3, p.-5, 995. WILMOTT, C.J.; ACKLESON, S.G.; DAVIS, R.E.; FEDDEMA, J.J.; KLINK, K.M.; LEGATES, D.R.; O DONNELL, J.; ROWE, C.M. Sttistics for the evlution nd comprison of models. Journl of Geophysicl Reserch, v.9, n.c5, p , 95. Received Jnury 3,