DRIS FOLIAR NORMS FOR COFFEE

Foliar diagnosis norms for coffee (Coffea Arabica L.) were developed through a DRIS approach by searching for, selecting and sampling, the most productive individuals of four coffee varieties (Mundo Nuevo, Caturra, Catuai Rojo, Catuai Amarillo) of different ages. Nutrient data of plants with yield over 7 kg per plant of cherry coffee, corresponding to the top 36% of the trees sampled, were computer stored to develop a data bank. Processing such data through conventional statistical methods, the norms were developed. According to DRIS system reports, mean values of each of the studied nutrients were developed as the norms. Finally, DRIS norms corresponding to the nutrient content in g per kg of dry matter of N (32.3); P (1.5); K (13.5); Ca (19.4); Mg (4.7) and on mg per kg of Zn (21); Fe (101); Cu (16) and Mn (196), plus the 36 binary relationships of quotients and products among those 9 nutrients were developed. Standard deviations and variation coefficients for each norm are also reported. Developed norms were compared with previously published values showing close values with previously reported coffee nutritional data. The close general agreement among the published values and the norms developed here plus the short length of time (2 years) used in this work for norms development, suggests the approach used could become an economic, relatively fast and reliable method for developing foliar diagnostic norms on perennial fruit plants, even without previous data.