Abstract:
Soil fertility is very important for sustainable agriculture. But modem agricultural
practices cause soil fertility losses and also soil degradation. So that the agroforestry
concept helps prevent soil degradation and also maintain soil fertility. Therefore this
study was carried out to find out the effects of agroforestry on soil fertility by
evaluating the N, P and K states of soils.
Two agroforestry land use systems namely alley cropping system and mix farming
system have been selected. For the comparison, adjacent two land plots without any
cropping system were selected as controls. Representative soil samples were taken
from 0-10, 10'20. 20-30, 30-40, 40-50 and 50-60cm depths from plots having two
different cropping systems and two control plots. Soils were brought to the laboratory
to be analyzed for total nitrogen, potassium, phosphorus and available nitrogen,
phosphorus and exchangeable potassium
When comparing the results, there was an increase of some nutrients in agroforestry
land use systems than control land. Total nitrogen, total phosphorus, total potassium
and available nitrogen, available phosphoms and exchangeable potassium were high
in mix fanning system than its control. Available nitrogen, available phosphorus and
total potassium were high in alley cropping system than its control. All the amounts of
nutrients decreased with depth. Because of that much of the nutrients accumulate in
the surface layer of soils. Total nitrogen, available nitrogen, available phosphorus and
exchangeable potassium were significantly high in mix cropping system than control.
From the results it can be concluded that the agroforestry systems could be practiced
to improve and maintain soil fertility by increasing N, P, and K status of soils.
