Sérgio Parreiras Pereira

Crescimento, produtividade e bienalidade do cafeeiro em função do espaçamento de cultivo

The objective of this work was to evaluate the consequences of spacing reduction between rows and between plants in the planting row on growth, productivity and bienniality of coffee plants (Coffea arabica). The experimental design was a randomized complete block, with three replicates, in a 4x3 factorial arrangement. Four distances between rows (2.0, 2.5, 3.0 and 3.5 m) and three distances between plants in the planting rows (0.50, 0.75 and 1.00 m) were used, which totalized 12 treatments. The productivity and the production per plant were assessed annually between 1994 and 2001, and the growth was evaluated in 2002. The reduction of spacing between rows and between plants in the planting row increases the productivity of coffee plants. The spacing between the rows and plants influences the growth and architecture of the coffee plant.

O alto teor de silício no solo inibe o crescimento radicular de cafeeiros sem afetar as trocas gasosas foliares

Several studies have confirmed the benefits of silicon (Si) for crop growth. The purpose of this study was to evaluate the effects of Si on the initial growth of coffee plants cv. Catuai Vermelho. This study was carried out with potted plants grown in a greenhouse, without water deficiency. Dry matter partitioning of roots, stems and leaves as well as the chemical composition of plant tissues and soil and leaf gas exchange were evaluated in plants treated with 0 (control), 1.5 and 6 Mg ha-1 of calcium silicate. The experiment was arranged in a randomized block design, with three treatments, and 3, 4 or 18 replications, depending on the evaluated variable. Each plot consisted of one plant. Regarding height and total dry matter, the plant growth was satisfactory in all treatments, with daily increases similar to the expected for well-fertilized coffee plants. The treatments resulted in increased soil and plant Ca and Si concentrations. Considering that only leaf Ca concentration was affected by treatments and its concentration was not deleterious, the observed responses are consequences of the high soil Si concentrations. Root dry matter of plants treated with 6 Mg ha-1 of calcium silicate decreased and the ratio between shoot and root dry matter increased 130 days after the beginning of the experiment. Despite the decreases in root growth and in Ca use efficiency, leaf CO2 assimilation and stomatal conductance of the coffee plants were not affected. In summary, high soil concentrations of calcium silicate decrease the root growth of Arabica coffee plants cv. Catuai Vermelho; however, the functionality and development of shoots in well-nourished plants growing under well-watered conditions are not affected.