Greening of India: Forests or Croplands?

Abstract

There are substantial changes in global green cover owing to anthropogenic activities and climate change. Here, we estimate the long-term changes in India's green cover, and its contribution from croplands and forests using satellite-based Normalised Difference Vegetation Index (NDVI) and Leaf Area Index (LAI) for the period of 2000–2019. The change in Solar Induced Fluorescence (SiF) is also estimated to understand the variability in the photosynthetic activity and productivity. The increase in NDVI (10%), LAI (11%) and SiF (13%) suggests that India has been greening in the past two decades, which added 996640 km² of new leaf area during the period. The net vegetated land in India is substantially greening (62.5% area) and marginally browning (14% area). Interestingly, the magnitude of greening in croplands is twice the forests, and is predominant in Zaid (70% area) agricultural season. Therefore, the croplands drive (86.5% contribution) greening of India in the past two decades. The enhanced greening of croplands can be attributed to improved irrigation facilities, as demonstrated by the larger Net Irrigated Area (NIA) and Irrigated Sown Area (ISA). In addition, the effective cropland management, farm mechanisation and use of nitrogen fertilisers are also key to this cropland-based greening in India.