crop yield in india in relation to ei-ninometnet.imd.gov.in/mausamdocs/54622.pdfmawam. (1995). 46,...

Mawam. (1995). 46 , 2, 127-132

551.526.6 : 633.1

Crop yield in India in relation to EI-Nino

A CHOWDHURYMeteorological Office. Pune

(Received 20 Novem ber 1989. Modified J1 May 1992)

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ABSTRACT. Associat ion between the El-Nino evems in the Pacific Ocean and the crop yields in Indiahas been examined. Five distrieu. riz. Cburu, Gwalicr , Rewa, Pala mau and Banku,.. 10C11ted on the normalmon soon trouJh zo ne and cul tiv8tine a1together different, mostly rainfed crops. were selected (or the study.Crop and 5e850na) rainfall data from 19S1 ·8~ "'.~~ util ised in Ute analysis.

The results indicate that the EJ-Nino phenomenon does nOI exert much influence on the kharifcrops in India.

Kry worm - 8-Ni no. Annawari system. Yield, Variability, SUl'ies. Sea surface temperatu re (Ssn.La-Nina. Trend.

1. Introduction

Variable climatic condition is wcll recognised 10

exert dramatic impact on the food production. Nodoubt, recent agro-tech nological inno vations. suchas. appropriate choice of crop stra in, intensiveirrigation, judicious water manage ment, pest anddisease control, large scale applicatio n of fertiliseretc, strongly influ ence crop yield and oftenameliorate the consequence of short term clima ticvariability. However, as sho wn by Me Quigg et al.(1973), the variations in crop yield are function s ofweather variability.

Largest climatic fiuctuations observed in recentyears are, perhaps. the ocean 's near sea-surface tem­perature (SSn field which occur over equatorialPacific Ocean. These interannual variations areoften referred to as EI-Mno and were recogniseddecades ago. Occurrence of EI-Mno events is ack­nowledged as associ ated with major changes inocean-atmosphere system across many parts ofthe globe,

Quinn et al. (I978) have shown that droughts inIndonesia coincide with El-Nino episodes. Droughtsin Australia have been observed in association withthese warm temperature events (Angell 1981).Bhalmt> (1984), Sarter (1987), Chowdhury andMhasawade (1991) etc., investigated associa tion

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between El-Nino and rainfall and droughts in India.However. stud ies linking the warm sea surfa ceepisodes of the Pacific with agricultu ral productionin partic ular. have, unfortunately, not attracted theattention of scientists in India.

In this pape r, possible associa tion between cropyield in selected locat ions and El-Nino have beenexplored to find out if the crop data coul d act asproxy for the monsoon climate.

2. Oa'a

Reliable crop data are available in India onlyafter 1950. Prior to that, crop estimation was don eby what is known as "a nnawari" system, which washighly subjective. We have, as such , used data from1951 to 1988. Five districts located on the norm alpositio n of monsoon trou gh zone, viz; Churu,Gwalio r, Rewa, Palamau and Banlrura were selec­ted in the study, These districts have tra ditio nallyrainfed agriculture with bajra, jowar and paddy asthe major crops. The yield data have been collectedfrom Agricultural Situations in Ind ia published byMinistry of Food and Agriculture. New Delh i.

Quinn et al: (I978) have categorised years withwarm episodes. A comparison of the same with thatgiven by Rasmusson and Carpenter {I983) revealedthat many of the cases do not agree. We have used