Maria Sueli Heberle Mafra

Estado nutricional, vigor e produção em videiras cultivadas com plantas de cobertura

Perennial or annual species of cover crops can be grown in vineyards to protect the soil surface and to reduce the availability of water and nutrients to the vine. The study aimed to evaluate the nutritional status, vigour and yield of grapevines intercropped with some species of cover crops under two different managements. A field experiment was conducted for two years, 2009 through 2011, in a vineyard of cv Cabernet Sauvignon in a Haplumbrept soil. The following treatments were evaluated: a control, where weeds were controlled by chemical drying in the grapevine row and by mowing in the inter row; a perennial species, tall fescue (Festuca arundinacea); two sequences of annual species, ryegrass-moha (Lolium multiflorum-Setaria italica) and oat-buckwheat (Avena sativa-Fagopyrum esculentum); and two types of crop residues management, with and without its transfer of the grapevine row to the inter row. The grapevine leaves were sampled at flowering and at berries softening stages for analysis of N, P, K, Ca and Mg contents. It was determined the branches and internodes lengths, branches pruned mass, grape bunches length, width and mass, yield per plant and the weight of 100 berries and it was also calculated the Ravaz index of the grapevines. Grapevines intercropped with succession of annual cover crops showed higher total N content in leaves at flowering, vigour and grape yield. The transfer of the crop residue from the row to the inter row, did not affect the grapevine vigour and yield, but decreased the total content of N in the leaves at flowering. The tall fescue as soil cover crop in vineyard can be an effective alternative to reduce the vigor of the grapevine.

Acúmulo de carbono em Latossolo adubado com dejeto líquido de suínos e cultivado em plantio direto

The objective of this work was to estimate organic C storage rates in an Typic Hapludox fertilized with soluble fertilizer and pig slurry and cropped under no-tillage. The experiment was carried out in the municipality of Campos Novos, in the state of Santa Catarina, Brazil, and the following treatments were applied annually: no fertilization; soluble fertilizer; 25 m3 ha-1 pig slurry + soluble fertilizer; and rates of 25, 50, 100, and 200 m3 ha-1 pig slurry. The following were determined: organic carbon (OC) stocks in the 0-20 cm soil layer; C inputs by crop biomass and pig slurry; annual C fixation rates; and the soil OC humification (k1) and mineralization (k2) coefficients. The real and apparent C fixation rates increased according to pig slurry rates, ranging from 0.6 to 1.7 and from 0.05 to 1.0 Mg ha-1 per year, respectively. The k1 and k2 coefficients were 0.17 and 0.011, respectively, whereas the C input required to maintain the initial stock of OC is of 4.14 Mg ha-1 per year. Pig slurry applied annually on a Typic Hapludox cropped with the maize-black oat succession under no-tillage increases soil OC in rates of up to 200 m3 ha-1.