Sensitivity of the agroecosystem in the Ganges basin to inter-annual rainfall variability and associated changes in land use

Type Journal Article - International Journal of Climatology
Title Sensitivity of the agroecosystem in the Ganges basin to inter-annual rainfall variability and associated changes in land use
Author(s)
Volume 34
Issue 10
Publication (Day/Month/Year) 2014
Page numbers 3066-3077
URL http://pure.iiasa.ac.at/10886/1/sensitivity of the agroecosystem in the Ganges basin to inter-annual​rainfall variability and associated changes in land use.pdf
Abstract
The rate of growth in agricultural production has been decreasing in several regions of the world in recent
years. The availability of water, which is one of the main inputs, is becoming limiting and more variable. In this article,
we study the sensitivity of the agroecosystem to rainfall variability in order to identify vulnerable areas. We applied a
longitudinal assessment of remote sensing time-series data, using the correlation between inter-annual rainfall anomalies
and anomalies in Normalized Difference Vegetation Index (NDVI), a proxy for crop production. With a novel approach, we
then identified whether the sensitivity results from a variation in crop growth or from a deliberate adjustment in the cropping
pattern, reflecting a coping strategy. In our case study area, the Ganges basin, 25% of the basin area showed a significant
correlation (p < 0.10) between rainfall and NDVI anomalies during the summer monsoon-dominated cropping season, both
positive and negative. During the consecutive dry season, 18 % of the basin area showed a significant correlation, mostly
positive. This variation in sensitivity shows the added value of spatially explicit information from remote sensing over
lumped crop statistics. Primarily in the drier western part of the basin, a coping strategy of increasing fallow land in years
with below-average rainfall was detected. Distinguishing a coping strategy from a crop yield reduction is important from
both an economic and a hydrologic perspective.

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