Efficient Nitrogen Management in the Tropics and Subtropics

Nitrogen (N) management is a serious problem especially in the tropics and sub-tropics, where heavy rains can come in short spells of time and lead to large runoffs and soil erosion; in well N fertilized fields about 5–8% of applied N could be lost from the point of placement to inland waters and estuaries. N lost as surface runoff is responsible for the eutrophication of inland water, estuaries, and the sea leading to the mortality of fish and other marine life. N leached from agricultural fields leads to nitrate pollution of groundwater leading to ailments such as Blue Baby Syndrome. Nitrous oxide produced due to denitrification leads to depletion of the ozone layer and global warming. It is important that improved N management practices, such as placement at seeding, split applications especially using leaf color chart or soil-plant analyses development meters, and foliar application need to be encouraged for increasing N use efficiency in the tropics and sub-tropics.