Alexsandro Oliveira da Silva

Crescimento e componentes de produção da mamoneira sob estresse salino e adubação nitrogenada

The research was carried out to evaluate the growth and components of production of the castor bean cv. BRS Energia under different levels of salinity of the irrigation water (CEa) and nitrogen doses under field conditions in an eutrophic Usthorthent of sandy loam texture in the municipality of Pombal, PB. The experimental design consisted of randomized blocks, testing five levels of salinity of irrigation water - CEa (0.4-control, 1.4, 2.4, 3.4 and 4.4 dS m-1) and five N doses (50, 75, 100, 125 and 150 mg kg-1) in a 5 x 5 factorial scheme with three replications. The increase of CEa from 0.4 dS m-1 reduced the number of leaves (NF), plant height (AP), stem diameter (DC), dry mass of the shoots (MSPA), cluster length (CRP), effective cluster length occupied by female flowers (CREFF), total number of seeds in primary cluster (NSRP) and total seed production (PSemT) of the studied castor bean cultivar. The interaction between water salinity and nitrogen dose for NF, DC, MSPA, CRP and CEes - electrical conductivity of the saturation extract of the soil was significant while the increase of nitrogen doses reduced the negative effects of salinity up to the level of 2.4 dS m-1. The CEes increased with increase in CEa and nitrogen doses.

Relações hídricas em cultivares de beterraba em diferentes níveis de salinidade do solo

The excess of salts in the soil can directly affect the development and yield of the plants, therefore, studies on water relationships of crops in such conditions are necessary to prevent or solve the problem. The study was conducted in a greenhouse at Universidade Estadual Paulista, Department of Agricultural Engineering, Botucatu, Brazil. The statistical design used was randomized blocks with four replications, consisting of five levels of soil salinity (1.0, 3.0, 6.0, 9.0, 12.0 dS m-1), two cultivars of sugar beet (Early Wonder and Itapua) and two types of management of fertigation, totaling in all 80 plots. Measurements of water content of the leaves, diffuse resistance to water vapor, transpiration, leaf area and the water consumption of crop were determined. There was a decrease according to increasing salinity for the analysed physiological parameters in the Early Wonder variety while for the Itapua variety a gradual increase was observed up to a salinity of 6 dS m-1. The water consumption by plants showed a reduction with increase of soil salinity for the two varieties.

Simulação do saldo de radiação na Serra da Mantiqueira

The influence of deforestation of the Atlantic Forest on the microclimate of the mountain Mantiqueira is not yet fully understood. To understand the consequences of deforestation on the highland climate research is needed about the surface radiation balance. The lack of data allows combining satellite images with meteorological data in a Geographic Information System in determining the radiation balance. The study aimed to evaluate the MTCLIM model in cloudless days or cloudy sky and simulate the radiation balance in the Mantiqueira mountain, between Sao Paulo, Minas Gerais and Rio de Janeiro, Brazil. Daily images, weekly and sixteen days MODIS available in 2003 were used in specific routines from MTCLIM. Specific targets were selected to evaluate the behavior of the radiation balance. It was observed that the radiation balance followed the local topography and is influenced by the type of land use. It follows that the surface temperature contributes to elevate the air temperature, resulting in lesser radiation balance on pasture. The MTCLIM model showed good correlation for air temperature (R2 = 0.82) and solar radiation (R2 = 0.71).

Nitrate and potassium movement in a sandy loam soil cultivated with fertigated grapevine (Vitis vinifera /L.) in the Brazilian semiarid

ertigation can increase the efficiency of fertilizer application and facilitate the nutritional management of a crop. Thus, nitrate and potassium movements in a sandy loam soil were evaluated as function of fertilizer doses during three growing seasons of the grapevine cv. Syrah grafted on Paulsen 1103 rootstock (June to October 2013, February to June 2014, and August to November 2014) in Petrolina, state of Pernambuco, Brazil. Five doses of N (0, 15, 30, 60 and 120 kg ha-1) and five doses of K2O (0, 15, 30, 60 and 120 kg ha-1) were combined in a fractional 52 factorial design, totaling 13 combinations, in a randomized blocks experiment with four replications. The concentrations of nitrate and potassium in the soil solution were determined. Samples were collected by porous cup extractors installed at 0.4 and 0.6 m depths. The movement of these ions was obtained by the product between their concentration in the soil solution and the soil water flux density. The increase in nitrogen fertilization promoted a greater movement of NO3- (62.2 kg ha-1) in the soil. The movement of K+ was also observed in two growing seasons .

Desenvolvimento de cultivares de beterraba sob diferentes tensões da água no solo

O deficit hidrico gerado pelo manejo inadequado da irrigacao pode afetar o desenvolvimento e producao das culturas. Com o objetivo de avaliar os efeitos de niveis de tensao da agua no solo sobre o desenvolvimento da beterraba, foi conduzido um experimento em casa de vegetacao em Botucatu, SP, entre abril e junho de 2012, em um delineamento em blocos casualizados com 4 repeticoes. Os tratamentos compreenderam seis niveis de tensoes de agua no solo (-15, -25, -35, -45, -55, -65 KPa) e duas cultivares de beterraba (Early Wonder e Itapua 202), totalizando 48 parcelas experimentais. Foram avaliadas a massa fresca e seca da parte aerea e da raiz, altura das plantas e o diâmetro da raiz. O aumento da tensao da agua no solo levou a reducao da producao e crescimento das plantas. De acordo com os tratamentos utilizados, o melhor desenvolvimento da cultura da beterraba, foi obtido com irrigacoes realizadas com valores de tensao da agua no solo em torno de -15 kPa e profundidade de 0,20 m do solo. A cultivar Itapua 202 apresentou menor crescimento das plantas e rendimento das raizes do que a Early Wonder, porem a reducao percentual em funcao da tensao de agua no solo foi equivalente para ambas as cultivares, plantas submetidas a tensao de -65 KPa apresentaram menores valores de producao e crescimento.

Acúmulo de micronutrientes em beterraba submetida a diferentes manejos de fertirrigação e niveis de salinidade

Knowledge of the amount of nutrients accumulated in the plant provides important information that can assist in the fertil ization of crops program. To study the salt effect caused by high amounts of fertilizers a pplied by fertigation, an experiment was conducted in a greenhouse at the FCA/UNESP, Bot ucatu, SP. The experiment lasted 90 days (01/11/11 to 29/01/12) constituting f ve levels of electrical conductivity (1.0, 3.0, 6.0, 9.0, and 12.0 dS m ), fertigation two management (M1: traditional management, M2: management by controlling the ionic concentration of the soil solution) and two varieties of beets (Early Wonder and Itapuã) blocks with 4 repeats forming a 5x2x2 factorial. From the dry weight of s hoots and roots was determined the levels of micronutrients (B, Cu, Fe, Mn, Zn mg kg ), and by multiplying the dry matter accumulation was determined in these plant . The ac cumulation of micronutrients in different parts of the plant followed the order: Fe > Mn> Zn> B> Cu for the different