The year wise total food grain production in the state for the years 1981 to 2007 is shown in Figure 7. It is generally observed that the total food grain production in the state was
- less than 12 million tons during the period up to 1987
- between 11 to about 13 million tons during the years 1988 to 1995 and
- between 10 to 19 million tons after the year 1996 onwards, Therefore, there was an increasing trend in the total food grain production in the state during the study period considered.
However, it is interesting to note that the total food grain production in the state during El Niño years fluctuated only between 9 million tons to 12 million tons up to the year 2002, although it ranged from about 9.5 to 15.0 million tons during the normal years. Therefore, there is an obvious signal that the total food grain production decreases by at least 0.5 million tons to 3 million tons during the years with El Niño, despite the increasing trend in the total food grain production in the state up to the year 2002. It was only during the recent two El Niño years 2004 and 2006, the total food grain production was above average. However, these two years were years with weak El Niño.
But the total food production during the years 2004 and 2006 declined compared to the corresponding preceding year, thereby confirming the fact that achieving an increased growth rate in food grain production may be a difficult task during El Niño years.
Figure 7. Year-wise total food grain production (‘000 tonnes) in Andhra Pradesh
The year wise yields of total food grains in the state for the study period are shown
in Figure 8. It can be noticed that the yields
– were 1100 to 1300 kg/ha up to 1987,
– increased to 1500 kg/ha up to 1992 from the year 1988, and
– varied from 1600 kg/ha 2400 kg/ha during the years 1993 to 2007
Figure 8. Average yield (kg/ha) of food grains in Andhra Pradesh (1981-2009)
It is interesting to note that above average yield of total food grains were achieved during the two El Niño years 2004 and 2006 which were weak El Niño years. However, it is interesting to note that yields during El Niño years were less than the preceding higher values thereby indicating the possibility of decline in productivity during the years with El Niño compared to previous year. Therefore, moderate and strong El Niño is a signal for declining trend in the yield, in general and weak El Niño events have exerted lesser influence on food grain productivity so far.
District-wise production and yield of total food grains
As El Niño suggests the possibility of decline in production and productivity of total food grains in the state, the district wise data were also analyzed to identify the districts which are more vulnerable to El Niño effect.
- the production was not affected only in S.P.S Nellore district which receives predominantly more northeast monsoon rainfall,
- the production decreased by 10 to 20 per cent in most of districts barring West Godavari and S.P.S Nellore districts, and
- Production declined by more than 15 per cent in Adilabad, Nizamabad, Karimnagar, Medak, Nalgonda, Mahabubnagar, Prakasam, Anantapur, Y.S.R Kadapa, Chittoor, Srikakulam, Vizianagaram and Visakhapatnam districts.
Therefore, the effect of decreasing tendency of the southwest monsoon rainfall on food grain production during El Niño years appears to be more in larger part of the state barring West Godavari, Guntur, Ranga Reddy and S.P.S Nellore districts.
Figure 9. Per cent change in average total food grain production during El Niño years compared to normal years in Andhra Pradesh (1981 – 2007)
The per cent decline in yield during the years with El Niño compared to the remaining years in different districts of Andhra Pradesh is shown in Figure 10. In general, the tendency is that the regions better served by northeast monsoon rainfall are comparatively less vulnerable to decline in productivity during El Niño years as the southwest monsoon rainfall has a tendency to decline in the state. The yields declined by more than 10 per cent in western parts of the state and as well as in Vizianagaram and Visakhapatnam districts which have lesser irrigated area.
Figure 10. Per cent change in average total food grain yield during El Niño years compared to normal years in Andhra Pradesh (1981 – 2007)
Therefore, it is obvious that El Niño is not a desirable signal from the point of view of total food grain production and productivity as well in larger part of the state, although the magnitudes vary geographically. In view of the above, detailed analysis was also carried out to find the changes due to El Niño effect in area, production and productivity of some crops rice, groundnut and pearl millet in different districts of the state for making an assessment of the El Niño factor on the performance of predominately irrigated and rainfed crops. The results were presented and discussed as follows.
- Central Institute of Dryland Agriculture