The various organic materials and proportions used as substrates for the production of guava seedlings can make a difference in the final quality benefits to the producer and the environment. The experiment aimed at to evaluate the effect of sources and proportions of organic materials on seed germination and growth of guava seedlings. The experiment was carried out during the period of September 2010 to March 2011, in the Experimental Farm of the Instituto Federal de Educação, Ciência e Tecnologia da Paraíba, located in the São Gonçalo Irrigated Perimeter, Sousa-PB, northeastern Brazil. It was used a randomized complete-blocks experimental design, with the treatments arranged in a 3 x 4 factorial scheme (bovine manure, ovine manure and earthworm humus in the following proportions: 0, 20, 40 and 60% v/v-1), four replications, and ten plants per experiment unit. The evaluated traits were: shoot length, stem diameter, shoot dry mass, root system dry mass, total dry mass, and macronutrient (N, P, K, Ca, Mg and S) contents in shoot dry masses. The ovine manure and earthworm humus are organic sources that provide the highest averages to the evaluated morphological traits. Independently of the organic source added to the substrate, 40% of the organic matter favored seedlings growth. Increasing proportions of organic sources in the substrate causes reduction in phosphorus content.
Psidium guajava; manure; macronutrient; substrate
