Spatio-temporal Pattern of Agro Ecosystem Net Primary Productivity of India: a Preliminary Analysis Using Spot Vgt Data

Indian landmass with 1.45% of the world’s total geographical area accounts for approximately 2.7–5.5% to the global NPP estimates with agriculture contributing to more than sixty percent. This paper reports the spatio-temporal pattern of agricultural NPP in India using SPOT VGT 10-day composite NPP product for 2002-03 to 2004-05 agricultural years. Detailed analysis was carried out for the Indo-Gangetic Region to analyse the temporal pattern of NPP for major cropping systems like rice-wheat, cotton-wheat, rice-rice, rice-potato etc. Results showed that total average crop year (June-May) NPP of Indian landmass was a little higher than 2000 TgC (Terra gram carbon) with more than 60 per cent contribution from agricultural vegetation. Annual rate of fixation for India in a normal monsoon year was high in forest ecosystems (a little more than 1300 gC/m) than cropland (a little more than 750 gC/m). Average rate of fixation varied from 900 to 1100 gC/m for rice-rice, rice-potato and sugarcane-based cropping systems in the Indo-Gangetic Plain (IGP). Significant year-to-year variation (22-25 per cent) in annual NPP was observed depending upon weather condition as it varied from 1881.64 TgC in 2002-03 (a monsoon deficit year) to 2515.22 TgC in 2004-05 (a normal monsoon year). Both agriculture and forest NPP showed a decline of 20-26 per cent in abnormal years.