Ana Carolina Feitosa de Vasconcelos

Land use dynamics in Brazilian La Plata Basin and anthropogenic climate change

The La Plata Basin (LPB) is one of the most important regions for agriculture and livestock production in South America, playing a central role in the world food production and food security. Within its borders is also located the whole Brazilian Pantanal region. Identifying the most important land use sectors in LPB as well as the changes observed in the past years is fundamental to recognize which areas of the basin might be more vulnerable to climate change in order to design adaptation strategies. A general characterization of land use and livestock production of Brazilian LPB was done by using the System of Automatic Retrieving (SIDRA) of Brazilian Institute of Geography and Statistics (IBGE) platform as the major source of data. It was observed expressive increases in land areas used for temporary crops, such as soybean, sugarcane, and maize, as well as increases in poultry and swine production. These important changes in agricultural land use and livestock production are currently associated to non-climatic drivers, but this dynamic might be strongly affected by the consequences of climate change and variability, with negative socio-economic impacts for the whole region.

Estimativa da acidez potencial pelo método do pH SMP em solos da Microrregião Homogênea Brejo Paraibano

The use of the pH SMP to estimate the potential acidity has advantages in relation to the 0.5 mol L-1, pH 7, calcium acetate method, but requires previous edaphic regionalization to estimate the potential acidity. The objectives of this study were to evaluate the soil-water-buffer ratio more adapted to soils from the homogeneous micro-region of Brejo Paraibano and to establish an equation to estimate the potential acidity of these soils by determination of the equilibrium pH of the soil suspension with the SMP solution. One hundred and twenty representative soils samples of the region were analyzed by the conventional calcium acetate method. Also determined was the pH SMP in the equilibrium suspensions soil-water-buffer 10:10:5, 10:20:10 and 10:25:5. The results have demonstrated that the best correlation between H + Al values and pH SMP was obtained with the 10:10:5 suspension and that the equation y = 164.31 - 47.26 x + 3.4717 x2, expressing H + Al (y) values in cmolc dm2, can be used to estimate H + Al values of the studied soils.

Alterações de atributos químicos do solo e do crescimento de plantas de milho pela aplicação de xisto

The objective of this work was to evaluate the effects of schist processing waste on soil chemical attributes and on vegetative growth of corn. The experiment was conducted in Regosol Eutrophic under greenhouse conditions. The treatments consisted of five rates of schist processing waste (0, 3, 6, 9 and 12 t ha-1) in a completely randomized experimental design with three replications. The schist was incorporated in the soil in each experimental unit, constituted by pots with 2 dm3 of soil, which remained incubated during 10 days. After this period the corn was sown and after 60 days the plant height, the stem diameter and the fresh and dry matter of the shoots were evaluated. Soil samples were taken from each experimental unit before and after sowing for chemical analysis. Application of schist promoted a significant increase in sulfur and silicon content in soil as well as in the total exchangeable bases, but there was no increase in soil pH. The growth of the maize was not influenced by the treatments.

Nutritional Analysis of BRS Topázio Cotton Plants with Omission of Macronutrients

In order to verify the nutritional disorders caused by the lack of macronutrients in the BRS Topazio cotton plants, an experiment was carried out in a greenhouse of diagnosis by subtraction, in which the following nutrients were omitted: N, P, K, Ca, Mg and S, with three replications totaling 21 experimental units. The omission of nutrients affected the production of phytomass in all treatments. The N content in cotton plants increased and decreased in the absence of K and Ca, respectively. The content of P increased with the omission of N, K, Mg, and decreased with omission of S. Regarding the content of K, it increased in the absence of S and decreased in the absence of N, P, K and Ca. The higher levels of Ca, Mg and S in cotton plants were observed with the absence of K.

Crambe Growth in a Soil Amended with Biochar and under Saline Irrigation

ABSTRACT Biochar is the term given to biomass subjected to the process of change in the composition by the action of high temperatures. Advantages of biochar in soil quality have been reported, including amelioration of salinity effects. Crambe has great potential to figure as raw material for biofuel, since it naturally contains up to 60% of erucic acid. This study evaluated crambe growth in a soil amended with biochar and irrigated with saline waters. A greenhouse experiment was conducted following a completely randomized design with five levels of biochar, two irrigation water supplies, and four replications. Parameters related to soil chemical properties, crambe growth, oil, and macronutrient contents were evaluated. Biochar presented significance for pH, electrical conductivity (EC), organic matter (OM), phosphorus (P), sodium (Na), and potassium (K) contents. Crambe growth parameters decreased with the doses of biochar. Oil and macronutrient contents were in accordance to previous studies.