Influence of tree canopy on microclimate modification and understory crop productivity

Abstract:

Imagine a smallholder field where trees shade half the ground yet the farmer harvests more total value per hectare than the neighbour who cleared every tree. This research measured how two levels of tree canopy cover dense (>70%) and moderate (40–70%) modified microclimate and affected understory crop yields in a Leucaena leucocephala-based agroforestry system at Sri Venkateswara Veterinary and Agricultural University, Tirupati, India, during 2021–22 and 2022–23. Dense canopy reduced photosynthetically active radiation (PAR) by 65.8% and air temperature by 3.8 °C but raised relative humidity by 12.7%. Understory groundnut yield was 28.4% lower under dense canopy compared with the open field, yet moderate canopy reduced yield by only 11.6% while cutting soil temperature by 2.9 °C. Land equivalent ratio (LER) peaked at 1.47 under moderate canopy. These findings indicate that managing canopy at 40–70% cover optimises the microclimate–productivity trade-off in semi-arid agroforestry.