Nitrogen levels and its correlation with the chlorophyll content in three coffee cultivars.

Three trials were conducted under greenhouse conditions using seedlings of 3 coffee cultivars Mundo Novo and Catuai (both Coffea arabica L.) and Apoata (Coffea canephora Pierre)and a range of N supply treatments from 0 to 98 mg/seedling. The chlorophyll contents were estimated using the SPAD 501 chlorophyll meter. Nitrogen supply and chlorophyll content were poorly related up to 20 days after N application. Subsequent to this, chlorophyll content of arabica cultivars correlated well with N supply, presumably as the seedlings became more dependent on soil N. Chlorophyll contents were maximal from 30 days after N addition at a N supply of 74 mg/seedling for the arabica cultivars and 84 mg/seedling for the Apoata cultivar. As N supply increased above these levels, chlorophyll content decreased.