“Spatial
Variability in Crop Yields: The Case of Cereals Across
Districts of Andhra Pradesh”
Citation: Ganesh-Kumar, A. 1999. “Spatial
Variability in Crop Yields: The Case of Cereals Across
Districts of Andhra Pradesh”. Indian Journal of
Agricultural Economics, 54(1), pp.53-78.
Abstract: Spatial variability in crop yields,
defined as the variations in crop yields across different regions during a
given time period, is studied in this paper for five major cereal crops (rice, jowar, bajra, ragi
and maize) across the districts of Andhra Pradesh in South India. As measured
by the coefficient of variation across the districts, spatial variability in
rice and jowar yields is found to be low and has
remained unchanged over time. Spatial variability in maize yields is found to
be low and increasing over time while in the case of ragi
and bajra yields it is high and increasing over time.
Factors influencing the spatial variability in crop yields are studied by
relating the coefficient of variation in crop yields to the coefficient of
variation in source-wise irrigation intensities, cropping intensity, fertilizer
availability and seasonal rainfall. It is found that (1) spatial variability in
rainfall has a direct effect on the spatial variability of yields of all crops
except bajra; (2) spatial variability in source-wise
net irrigation proportions affects the spatial variability in yields of all
crops except jowar; (3) spatial variability in
surface water sources of irrigation (canals + tanks) has a direct effect on the
spatial variability in yields of rice, bajra and ragi; particularly spatial variability in tank irrigation
has a direct influence on the spatial variability in bajra
and ragi yields; (4) spatial variability in ground
water irrigation (tubewells + other wells) has an
inverse effect on the spatial variability in bajra
and maize yields; (5) spatial variability in aggregate cropping intensity has
an inverse relation with the spatial variability in bajra
and ragi yields; and (6) spatial variability in
fertilizer use has a direct effect on spatial variability in rice yields and an
inverse effect on ragi and maize yield spatial
variabilities.