Leonardo Elias Ferreira

Adubação orgânica da batata com esterco bovino no município de Esperança - PB

In the Paraiba state the potato shows a low yield, due to the rain seasonality allied to the low soil fertility. This study aimed to evaluate the bovine manure efficiency in the organic fertilization of potato. The experiment was carried out in Esperanca county, in a Regolithic neossoil. The design used was randomized blocks, with bovine manure application in quantities of 0; 3; 6; 9; 12; 15; 18; 21 and 24 t ha -1 and 10 t ha -1 of bovine manure + NPK with percentages of 0; 12.5; 25; 37.5; 50; 62.5; 75; 87.5; and 100% of the formula 120-80-90 ( N-P2O5-K2O ), calculated by the soil analysis. The variables evaluated were: number and weight of tubers per plant, total yield and commercial; yield losses and dry matter of tubers. The use of bovine manure and bovine manure + NPK provided an increase in weight of tubers per plant, total yield and commercial potato tubers. This way, it is observed that the bovine manure is a good alternative as organic fertilization to the potato producers of this county.

Diâmetro de estacas e substratos na propagação vegetativa de maniçoba, Manihot glaziovii Muell. Arg

Objetivou-se com este trabalho estudar a influencia do diâmetro das estacas e dos substratos na propagacao vegetativa de manicoba, Manihot glaziovii Muell. Arg. Utilizou-se o delineamento em blocos casualizados em esquema fatorial 10 x 3, sendo 10 substratos e 3 diâmetros de estacas, totalizando 30 tratamentos, oriundos das combinacoes entre substratos e diâmetros de estacas, com 4 repeticoes e 8 estacas por parcela. Os diâmetros das estacas corresponderam a: 0,5 a 1,0 cm (D1); 1,1 a 2,0 cm (D2) e 2,1 a 3,0 cm (D3). Foram utilizados 10 substratos: terra (S1); areia (S2); terra+areia: 1:1 (S3); terra+areia: 2:1 (S4); terra+areia: 1:2 (S5); terra+esterco: 1:1 (S6); areia+esterco: 1:1 (S7); terra+esterco: 2:1 (S8); areia+esterco: 2:1 (S9) e terra+areia+esterco: 1:1:1 (S10). As estacas lenhosas foram retiradas de plantas matrizes em repouso vegetativo, com comprimento de 25 cm e base cortada em bisel. Avaliou-se: percentual de estacas enraizadas; numero de raizes; numero de brotacoes; diâmetro e comprimento das brotacoes; numero de folhas; massa seca das brotacoes e massa seca das raizes, obtidos aos 70 dias apos instalacao do experimento. Os melhores resultados para todas as variaveis estudadas foram obtidos com estacas de diâmetros entre 1,1 a 2,0 cm e entre 2,1 a 3,0 cm, com substratos que incluiram areia + esterco na sua composicao. Tais tratamentos proporcionaram percentagens de enraizamento da ordem de 70 a 80%.

Propriedades físicas e químicas em diferentes usos do solo no Brejo Paraibano

The substitution of the native vegetation of marshlands in Paraiba, initially by sugarcane and more recently by pastures, in a strongly undulated relief, has caused serious problems of soil degradation. Currently, some of these pastures are being replaced by plantations of sabia (Mimosa caesalpiniaefolia Benth). The objective was to analyze the effect of these changes on the soil physical and chemical properties and root development. The experiment was conducted in Areia-PB, in a dystrophic Ultisol. The three treatments were represented by three land uses:secondary native forest, sabia plantation, and brachiaria pasture grass (Brachiaria decumbens). Soil samples were collected from three slope positions: top, middle, and bottom. For physical properties and root studies, in each position soil was collected at three different points and in four depths (0.0-2.5, 2.5-5.0, 5.0-10.0, and 10.0-20.0 cm). Composite samples were made to assess the chemical properties and clay content. The experiment was conducted in a completely randomized design with repeated measures in space. The results showed better aggregation, density, and porosity in the area of native secondary forest. The replacement of pasture by sabia lead to a decrease in the aggregation but did not affect bulk density or soils total porosity. Nutrient levels were higher in the sabia area, although statistically different just for K and saturation of exchangeable bases. Changes in land use invariably degrade soil physical and chemical properties, but when a less aggressive system is introduced, changes are hardly detectable in the short term.

Growth and gas exchange in cowpea plants under different managements and saline conditions

The cowpea is one of the main crops of economic and social importance in the northeast of Brazil. However, the growing need to increase crop yield has prompted the use of irrigation water with high levels of salts. The aim of this study therefore, was to evaluate the effects of different irrigation depths and rates of liquid biofertilizer on growth and gas exchange in cowpea plants under saline conditions. The experiment was conducted in a randomized block design, using a scheme of split lots consisting of four irrigation depths with saline water (75, 100, 125 and 150% of crop evapotranspiration - ETc) and sub-lots of four different doses of biofertilizer (0; 5,000; 10,000 and 15,000 L ha-1). At 75 days after sowing (DAS), readings were taken of gas exchange in the plants (photosynthesis, stomatal conductance, internal CO2 concentration and transpiration), and growth analyses were carried out (plant height, leaf area and total dry matter). An increase in irrigation depth gives an increase in total dry weight and leaf area. Increasing irrigation depth causes a significant increase in gas exchange, with quadratic behavior noted for photosynthesis and stomatal conductance, and linear behavior for internal CO2 concentration and transpiration. The application of high doses of biofertilizer gives increased stomatal opening of the cowpea leaves.