Effect of organic fertilizers on soil chemical properties and performance of blackberry (Rubus adenotrichus) in two agroecology zones of Costa Rica

The effect of two organic fertilizers on soil chemical properties and plant performance blackberry (Rubus adenotrichus cv.Vino) in two areas of Costa Rica were evaluated. For this purpose, two experiments were established, one in Buena Vista of Perez Zeledon (BVPZ) and another in San Martin of Leon Cortes (SMLC), both in the province of San Jose, Costa Rica. The research was conducted between August 2005 and July 2008. Three treatments were evaluated in each experiment: Compost (C) and Vermicompost (L), at the rate of 4 kg/plant and 3 kg/plant respectively, and a control without fertilizer (T). The frequency of application of fertilizer at planting was given at 6, 12, 18 and 24 months for a total of 6,6 t/ha for C and 4,9 t/ha for L. Soil samples were taken at 0, 6, 12, 18, 24 and 35 months, after planting for analysis. The results have shown that in both agro-ecosystems, the application of C and L has increased soil pH, reduced acidity, has increased the availability of Ca, Mg, K, N, and P, and has favored the effective cation exchange capacity (ICC) and the percentage of organic matter. The accumulation of Mn, Cu and Zn was not observed. Performance-wise, in BVPZ only significant have found differences (P = 0,00188) between C (1,8 t/ha) and T (0,9 t/ha), while in SMLC, found no differences statistical significant (P <0,05) between treatments. (author)