Multi-temporal AWiFS and SAR data for cropping system analysis in Indian Punjab

Abstract

The analysis of cropping systems using remote sensing is crucial to the long-term sustainability of agricultural productivity, soil and environmental health through diversification and intensification of crop areas. Realizing the importance, mediumresolution satellite data from advanced wide field sensor (AWiFS: 56 m) and synthetic aperture radar (SAR: 50 m) were used to generate land use, cropping pattern and crop rotation maps for the state of Indian Punjab. To evaluate the efficiency of cropping systems at district level, various remote sensing derived efficiency indices were worked out. The spatial analysis revealed that agriculture covered 86% of the total geographical area (TGA) 5.04 M ha, while forests covered only 2.6% of TGA. Rice was the most dominant crop, occupying about 51.2% TAG of the state during the kharif season (first harvest: June to Nov). During the rabi season (second harvest: Nov to April), wheat was the most dominant crop, occupying about 3.52 M ha of state area (69.8% TAG). Summer crops (April to May), primarily vegetables, were grown in 5.3% TGA of the state. Rice followed by wheat was the main crop rotation in 43.6% of the TGAs. Apart from rice-wheat, other crops-wheat and cotton-wheat rotations also occupied a considerable agricultural area in the state (16.9% and 9.1% of TGA, respectively). In much of the region, crop intensity exceeded 200% (double cropping). The crop area diversity was considerably higher during the kharif season (ADIK: 2.23) than during the rabi season (ADIR: 1.60) and the land remained in cultivation 292 days yr-1. Incorporation of medium resolution SAR data with AWiFS data of high temporal (5 days) resolution helped to overcome the limitation of the non-availability of multispectral optical images during the kharif season because of cloud cover. This has improved the precision of the analysis of cropping systems, especially in the mapping of rice growing areas.