Agrometeorological analysis and crop yield modeling can help determines operations aimed at increasing and establishing agricultural production..

Huda, A K S

ICRISAT Open Access Repository

Agrartwtologi or1 r ~ l y r i a  md crop .odeling ern help detenlnr oprrrtionr r iard  a t  incrrrrinp and litrbiliaing agriculturrl probuction. The objrctiorr of thi; paper a r e  to illurtrrt., w i n g  a p a r 1  millet mobrl, ( i )  the utility of agrowt~orolopiorl drtr in rarrrring rowing dater md in rrtimrtinq ptobrbilitirr of production potential of p a r 1  millet in rrinfed agriaulturr, mb (ii) thr limitation8 experienced in uring thr model to rinulrte crop yie ld8  over large 4reae* A millet model developed a t  ICRISAT (Huda, 1987) ir bared:on 1 infornation of crop, climate, and roil? it operate8 on r dai ly  a The durationr of growth rtrgrr are determined f cultivar coeff icientr of the effccta of trmprature. Daily area progrerrion i 8  calculated by an input of mximua leaf r er i index a t  antheail. The duration8 ( t )  of three growth r t r q m '  e m r g m c e  to panicle initiation (681) , prnicle initiation to * Prepared for the Wotkrbop on Crop Yield Hodtling held rt the Indian Bpcr ApOl  icrt ia Center , ~haedahad, 27-28 July 1988. ** Agroclimatoloqirt , ReIOllrce ~ l m r g e r n t  Program, lntrrnrtionrl Cropr Rcrearch lnatitutr for thr S n l - A r i d  Tropic8 (1QIUTlr R t U ~ b a r u r  A.P. SO2 324, India* antheair  (CB2)r and r n t h e r i s  t o  phyrioloplcrl maturity (GI)) 1 - * (T - Tb) / e l ,  when T,, To or, t T average r i t  temperaturet Ttj bare tmperrture ( ~ O ~ C ) ,  To - optimum a i r  temperature (30°c) 8 thermal tire for a developlarntrl 8th (310 for CSl, 530 for  GS2, 450 for G t 3) I Daily potential  dryarrttar production is  ~ l ~ u l r t e b ~  basedon l i g h t - u r a  eff ic iency and l i g h t  i n t e r c e p t i o n  ( 2 d 2  g of dry m a t t e r  p e r  MJ o f  P h o t o r y n t h e t i c s l l y  A c t i v e  R a d i a t i o n  i n t e r c e p t e d ) .  D a i l y  n e t  dry-matter  g r i n  i r  c a l c u l a t e d  by a c c o u n t i n g  f o r  r o i l  w a t e r  deficite. The water d e f i c i t  c o e f t i c i a n t r  (WATDCO) were d e r i v e d  from f i e l d  experiment8 conducted a t  XCRISAT Center (Jarval,  1 9 8 0 ,  and the  algorithms used in tha model are ar follows: SW WATOCb = 1 . 0 ,  when (1  - --) ,( Oe2S,  UL m ox: - 0, when (1 - - > 0-75 UL I wb.rer BW simul8t.d available mil  vater on any &y 1 UL - ~vailable m t e r  holding uprc i ty  o f  the root rma. Grain yield i a  rWulr te6  by win9 input on c~lttver-rprolfia hrrvrtst i *x .  A8nrrfng 8ouiag &tar m i l y  c l i u t i c  data from 1930 to 1987 were ured t o  rrrerr rowing dr t r r  and t o  r i m u l a t e  p r r r l  m i l l e t  y i e l d  under r a i n t o d  condition#, 88 an i l l u r t r r t i o n ,  for .one reptr8.ntrt ive prrrl millet  r r e r  of India (Jodhpur, 26'1, 73%). I n  Jodhpur, monroon rain. normally r e t  in during the f i r r t  week of Ju ly  rnd the i r  withdrrwrl occur, during tha f l r r t  week of September J t h u r  there are  only two rainy months. Aowever, thare war r l r rge  v r f i r t i on  among yer r r ,  par t icular ly i n  the  onret of rain for rowing. To rtart r cropping rearon, we chore r rowing date r f t r r  1 June when ' a t  l e a s t  30 mm r a i n  f e l l  w i t h i n  t h r e e  conreoutive dry# .  The p r o b a b i l i t y  of roving m i l l e t  i r  28, by 1 J u l y ,  658 by 15 July (Pigurr  1). Simulated rowing d a t e r  matched t h e  a c t u a l  roving date. in Jodhpur during IS71 t o  1985, wi th  one exception. Wo r s t i u t e d  from long-term c l i u t i c  analyrir that crop8 rhould have boan mrom i n  5 of  tho SO y a r t r  baaure there war no rain for wrs thur 20 dryr a f t e r  tb f i r r t  rrowing, the cr i t e r ion  for f a i l u r e  of crop e#tablirh.*nt. Figure 2 rbowr the p t o b r b i l i t y  of rece iv ing  l o r  thrn r 8p.cifi.d amount of r a i n  during  t h e  r imula ted  grovlng period bared on data from 1930 to  1987. RaL.lnf111 ranged fro l  71 r t o  710 m wi th  a maan of 27a mr. I n  70* o f  tha y a r r r ,  rrinfrll during the proving 8earon war lerr thrn 320 m. Yiald 8Ulat ion Grain y i e l d r  o f  a rtrndasb p a r 1  millet c u l t i v a r  (7s &yr to luturity) were rinu1at.d urlnp c l iu t f c  &tr of Jodhpur f r a  1930 to 1987, and rrruming optimm plant rtrnd, adequate notrienta, mb plant protection. The rimulated yield ranged frm nothing to 3.2 t hawf, mrtchinp the rrnge of actual yield.'obtained a t  Jodhpur ftom 1971 to 1905 ( t i p u r e  3 ) .  Though tb rimulrted yield 4 matchad the rc t u r l  yield in v e r y  d r y  y e a r 8  r n d  i n  well dirtributsd rrinf~ll year#, in 80% o f  th. ycrrr rimulrted y ie ldr  were greatst  than r c t u r l  yieldr. Tb*re comparirenr ruggert  that t h o u g h  t h e  model rimulated the effect8 of v r t c t  drticitr rarronrbly well8 mom of  the rrruaptionr mda in tbir  rirulation rtody are  not correct8 and t h e  model need8 rsfini~g. -1 miinlag (i) Thr arrumption 02 the optima plant rtand m ~ u l t l n g  in 90% or aoto light interception a t  anthamis my k obtained in well blstributeb r a i n y  rearona, but for tbore yearr when long dry up118 occur, rppropriate correction in the model eonputation o f  daily leaf area prog~earion &r to be mde (light verroa water as limiting factor). ( i i )  The use o f  458 harvert  index to convert rimulated total dry matter to grain yie ld  may be cocrect i n  yearn where r a i n f a l l  i s  well distributed, but  rpproprirte c h a n g e r  in t b e  sodelled dirtr ibut ion  of the  dry u t t e r  t o  gra in  needr t o  k made for tho8e year8 vben reverr  drought r t re88 O C C u t r  during the grain-filling period. (iii) W t i o  of 6 t y ~ t t . t  rcarrulrtlon and vatrc rupply mad# to be computed by acoountlng for saturation d e f i c i t  of the air .  Saturat ion hficft i 8  l inked with 8errlonrl rrifiFa11 (Uonteith, 1986). ( i v )  The rodel ahould recount fot nuttient and b i o t i c  r t te l i re8 and t h e i r  i n t e rac t  ionr w i t h  m v i t o m n t a .  For rxamplr, if  t h a t .  i a  n o t  enough r o i l  m o i s t u r e  i n  the t o p  r o i l ,  nu t r i en t8  applied through f q r t i l i t e r  vould not hrvr been r v a i l r b l e  t o  the plrnta .  r.pliortionr (i) To a r r e r a  t h e  effect8 of b a t e s  of rowing on f i n r l  g r r l n  y i e l d  of p e a r l  millet e . .  r i r k r  i n  rbrndoning  f i r r t  p l a n t i n g ,  i f  i t  i a  fol lowed by a long  ~ r i  r p r l l ,  vareur plan t ing  again upon r@ceivlng r u i i i c t e n t  rub,.quent ra in ) ,  ( t i )  Adopting appropr ia te  management p rac t i ce r  t o  improve the actual  yie ld# .  ( i i i)  To car ry  out  preliminary r t u d i e r  on genotype x environment i n t e r a c t i o n  by a raaar tng  b o t h  p o t a n t i r l  y i e l d  and a t a b i l i t y  of y i e l d  over ysazr. Dlfflmltiee in Sztanding Yield Simulatioa met. Utg. A r u m  (i)  Tbe need for  model refinement, am alrardy dircumed.  (ii) Anong t h e  climatic data, only d r i l y  r a i n f a l l  drtr are n o r v l l y  available for longer ternml data on other  rrpctr are u w a l l y  in6ufficirnt. Data need. are given i n  table 1. (i i l)  S p t i a l  v a r i a b i l i t y  of ra infa l l  and aoilr. ~ l ~ t 8  I would like t o  exprerr my rincere tbrnkr and gratitude t o  Dr. Y.8. Rur Zri ~ h n r ,  C8nttrl Arid tone Re8mrch fnrtitute, Jodhpur for #upplying th. c l i ~ t i c  data, to Clt. 0.V. Ramam ko, Central M#~&scR Snatitute for Dtylmd Agrf c ~ l t u ~ e ~  f o r  mupplying actual y i e ld  &t& of prc l  millet, t o  Dr. J.L. h n t e f t h  for h i s  valuable commntr, to nr.  D. Mtdyr for h i 8  rralrtcnce i n  anrlyring tbe data. an8 to Us. f . P . C . 8 .  Raju for typing t h e  uauscr ip t .  lhf e t e w r  1 B u d ,  A . I . S .  1907. Simulating y i e l d s  of r o ~ g h u a  bnd perf1 i a i l l e t  in the #)mi-arid t r o p i c e .  F i e l d  crop8 Rerarrch 1 s t  309-325.  2. J&rwal, S.D. 1984. Canopy archit*cture, l i p &  interception, r4t.r use, and dry u t t e r  ptoduction r c l a t i ~ n r l i i p  in pearl millet (- (L.) Leak*). Ph*Do The8it a u k i t t e d  to Baryanr Agricultural Univerrity, Iirac.  189pp. 3. Ilontrith. J.L. 1986. Signi f icance of the coupling between rrturrtion vrpour ptarrure d e f i c i t  and rainfall in mnroon t e a  Expsimental Agriculture 22r 329-338. -&la 1. mta mad8 for d.ttrloprrcnt and tertinq of  r p r r l  millet v Rrinfrll Temprrtatuta U d i e t  ion Oprn prn Refstivr hunidit  r Saturation &@Fie tSail i n f o r u t  c h m  Wpr, h p t h  Wrtw - holding capacity Spwirl ptoblan Plant atrnd Nutrient8 Biotic Irr iga t ion ,  Crop y i e l d r  ti-. m*iacl Pigurrr 1. Cc#pri&on k t w w a  actor1 md 8inulrt.d prabbilitier ot rowing prr l  millat (on r day) kt-en Z 3um rnb 31 Augurt i n  Jodhpur. Figure 2. Probability o f  lrrr than r rprrcfffad uount of rrtntrll during the rimulrted growing rarron of paan millet in Jodhp~  t . Figure 3.  Prob.bilitiea of lea8 than a rpc l f i8d  w u n t  of actual end rimulrteb p r r l  millet grain y i e l d  in Jodhpur. Biaulrted Grrin Y i a l d  o f  Pearl  nillet and Serron@l ltciaL11l S t r t i o n  t Jodhpur Yer r 

Agrometeorological aspects of crop yield modeling: data needs and limitations

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Agrometeorological aspects of crop yield modeling: data needs and limitations

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