Estudos sobre a alimentação do cafeeiro: XIV. efeitos da adubaçao mineral e orgânica na produção e na composição das folhas

Abstract

This paper deals with the results of a 2 x 2 x 2 N P K experiment designed to study the effect of fertilizers on yield and a chemical composition of coffee leaves; the effect of organic matter supplied as stable manure was ascertained by using the split plot technique. Yield data refer to the six harvests obtained from 1958 to 1963 only chemical data obtained in 1962 are discussed. Both N and K raised significantly the yields, their positive interaction being also significant; no affect of P was observed; organic matter did increase total yield; its effect cannot be atributed to additional supply of N, P or K. Yields are diminishing in a significant rend; several suggestions are discussed in an stempt to explain this finding. The doses of N and K which have been applied proved to be suficient to maintain an adequate level of said elements in the leaves.