Anamari Viegas de Araujo Motomiya

Utilização de sensor óptico ativo para detectar deficiência foliar de nitrogênio em algodoeiro

Visou-se com este trabalho, avaliar, em condicoes de campo, o efeito da variacao de doses de nitrogenio na deteccao do teor de nitrogenio foliar do algodoeiro (Gossypium hirsutum L. var. latifolium Hutch), utilizando-se propriedades de reflectância obtidas por um sensor optico ativo. O delineamento experimental foi o aleatorizado em blocos, com cinco tratamentos (0, 50, 100, 150 e 200 kg ha-1 de N) e quatro repeticoes. Os dados do Indice de Vegetacao Diferenca Normalizada (NDVI) e da razao simples vermelho/infravermelho proximo (V/IVP) foram coletados no periodo de 23 a 92 dias apos a emergencia (DAE) totalizando nove datas de coleta; coletaram-se tambem dados referentes ao indice de clorofila, indice de area foliar (IAF) e altura de plantas. Os valores do NDVI apresentaram tendencia crescente ao longo do periodo das leituras, enquanto a relacao V/IVP teve comportamento inverso e, a partir de 45 DAE, foram afetados significativamente pelas doses de N aplicadas. Relacoes significativas foram observadas entre os valores do NDVI, indice de clorofila e IAF; aos 92 DAE o NDVI apresentou relacao linear positiva e altamente significativa com o teor foliar de N. O sensor utilizado pode ser uma ferramenta efetiva para estimar a deficiencia foliar de nitrogenio em algodoeiro.

Spatial variability of soil fertility and its relationship with seed physiological potential in a soybean production area

The correlation of soil fertility x seed physiological potential is very important in the area of seed technology but results published with that theme are contradictory. For this reason, this study to evaluate the correlations between soil chemical properties and physiological potential of soybean seeds. On georeferenced points, both soil and seeds were sampled for analysis of soil fertility and seed physiological potential. Data were assessed by the following analyses: descriptive statistics; Pearsons linear correlation; and geostatistics. The adjusted parameters of the semivariograms were used to produce maps of spatial distribution for each variable. Organic matter content, Mn and Cu showed significant effects on seed germination. Most variables studied presented moderate to high spatial dependence. Germination and accelerated aging of seeds, and P, Ca, Mg, Mn, Cu and Zn showed a better fit to spherical semivariogram: organic matter, pH and K had a better fit to Gaussian model; and V% and Fe showed a better fit to the linear model. The values for range of spatial dependence varied from 89.9 m for P until 651.4 m for Fe. These values should be considered when new samples are collected for assessing soil fertility in this production area.

Mapeamento do índice de vegetação da diferença normalizada em lavoura de algodão

The remote sensing data obtained at field level can provide detailed information about the variability of biophysical parameters related to yield over large areas, and present potential for monitoring these parameters throughout the crop development cycle. This study aimed to map the spatial variability of the Normalized Difference Vegetation Index (NDVI) and its components in two commercial cotton ( Gossipium hirsutum L.) fields, by using an active optical sensor at the ground level. Data were collected with the aid of an optical sensor installed in a self-propelled agricultural sprayer. A GPS receiver was connected to the sensor, in order to obtain the coordinates of the sampling points. The readings were performed in rows spaced 21.0 m apart by the sensor installed on a vehicle, during the spraying operation, and data analyzed by using the classical statistics and geostatistics. Spatial distribution maps of the variables were generated by kriging interpolation. It was observed a higher spatial variability of NDVI and spectral reflectance of vegetation in the region of near infrared (NIR) (880 nm) and visible infrared (590 nm) in the crop with higher physiological stress, due to the brown bug [ Scaptocoris castanea (Hem.: Cydnidae)] attack, when compared to the healthy one.

Impacto energético da irrigação por gotejamento no cultivo de mamona

Irrigation is a technique with high potential to increase crop yield , however, it is necessary to evaluate the energetic efficiency of irrigated agriculture. So, this study aimed at evaluating the irrigation impact on grain yield and energetic balance of two castor bean cultivars submitted to supplementary drip irrigation with different water depths. The experiment was conducted in a clayey Dystrophic Purple Latosol, in Dourados, Mato Grosso do Sul State, Brazil. The experimental design was randomized blocks in a bifactorial scheme, with five water depths (0%, 25%, 50%, 100% and 150% of evapotranspiration for localized irrigation) and two castor bean cultivars (IAC 2028 and IAC 80), with four replications. The irrigation interval was of up to two irrigations per week, except for the days when rainfall occurred. Crop yield and the relation energy produced in the form of grains/energy used in cultivation were evaluated. It was concluded that the supplementary irrigation increased yield, as well as the relationship between energy production and consumption.

Diagnose nutricional com o uso de sensor óptico ativo em algodoeiro

This research aimed to evaluate the spectral response to variation of nitrogen levels and its relationship with leaf nitrogen, chlorophyll and yield in cotton crop. The experiment was conducted in Chapadao do Ceu, MS, in a randomized block design with four replications. The treatments consisted of five N rates of 0, 30, 70, 110 and 150 kg ha-1, divided in two applications at 28 and 41 days after emergence, using urea fertilizer as a source. The highest correlations of the chlorophyll index and normalized difference vegetation index with yield were observed in the fourth observation, at 56 days after emergence, indicating that in this period, yield may already be compromised if there is shortage in the supply of N to the crop. The results obtained indicated that the sensor becomes more sensitive to variations of nitrogen levels as the crop grows, but not when it reaches a high leaf area index and in the begining of the senescence. It is concluded that ground level remote sensing permits to estimate indirectly the amount of N absorbed, chlorophyll index and cotton yield.

Análise econômica e viabilidade energética da cultura do feijoeiro comum sob irrigação

This study was conducted to evaluate the economic and energetic viability of the third season of common bean under irrigation depths in the northwestern region of Parana. The experiment was established with six irrigation levels and four replications in a randomized block design. The bean crop was not economically viable without irrigation. Operating profit increased with increasing irrigation depths, reaching a total operating profit of R

Produção de almeirão em função de níveis de fertirrigação nitrogenada e disposição de mangueiras gotejadoras nos canteiros

1,427.24 ha-1 by 333 mm irrigation depth. The equilibrium price without irrigation was R

Test procedure for variable rate fertilizer on coffee

134.06 and R

Vegetation index in cotton under rates of nitrogen and growth regulator

152.65 bag-1, short and long term, respectively. The irrigation favored the energy balance extracted (energy/used energy), reaching 1.63 in the application of greater depth (333 mm).

Spatial variability of soil properties and cotton yield in the Brazilian Cerrado

O objetivo deste trabalho foi avaliar os efeitos de diferentes niveis de fertirrigacao nitrogenada na produtividade e nas caracteristicas agronomicas de plantas de almeirao, irrigadas por gotejamento. O delineamento experimental foi o de blocos casualizados em esquema de parcelas subdivididas, sendo avaliadas nas parcelas duas formas de disposicao das mangueiras gotejadoras (superficialmente sobre o solo do canteiro e subsuperficialmente) e nas subparcelas seis doses de nitrogenio: 0, 30, 60, 90, 120 e 150kg ha-1. A forma de disposicao das mangueiras afetou a producao apenas da massa fresca, com o melhor resultado sendo obtido com a irrigacao subsuperficial. A producao e as caracteristicas agronomicas do almeirao foram influenciadas pelas doses de nitrogenio aplicadas na agua de irrigacao nas duas formas de disposicao das mangueiras nos canteiros. A maior eficiencia financeira da adubacao foi obtida com a dose de 30kg ha-1 de N nas duas formas de disposicao das mangueiras gotejadoras.