Darly Geraldo de Sena Júnior

Discriminação entre estágios nutricionais na cultura do trigo com técnicas de visão artificial e medidor portátil de clorofila

Sidedress nitrogen fertilization is currently discussed throughout the world due to its economical and environmental implications. The cereal crops strongly respond to N application and there is a lack of current methods to determine N availability on the soil. The aim of this work was to evaluate the discrimination among three nutritional levels in wheat crop using digital images and a portable chlorophyll meter. Data were collected in plots with three levels of N (0; 30 and 60 kha-1) in three dates (8; 14 and 20 days after sidedress fertilization). The images were processed using nine spectral indices and elaborated multivariate classifiers based on the mean pixel values. The chlorophyll data and leaf nitrogen concentration were used in univariate classifiers. The classification using the machine vision techniques were better than the chlorophyll meter (SPAD) at 8 DAF, since the Kappa coefficient was better than a random classification. At 14 and 20 DAF there were no statistical differences between this type of data and the data from images. Using digital images it was possible discriminate the nutritional levels eight days after sidedress fertilization.

Growth and nodulation of soybean plants fertilized with poultry litter

Nowadays much of the chemical fertilizers used in Brazil come from imports, what creates the necessity to seek for alternative fertilizers. One possibility is organic fertilizers, including poultry litter, which presents increasing availability in various regions of the country, due to the expansion of the poultry industry. Despite its availability, there are no enough studies that show the benefits of using poultry litter on soybeans in substitution of mineral fertilizer. The present study aimed to evaluate the effect of different doses of poultry litter on leaf chlorophyll content, nodulation, and development of soybean plants. It was used a completely randomized design with five doses of poultry litter (0, 1, 2, 4 and 8 t ha-1) and a control with mineral fertilizer with four repetitions. On stages R1 and R5, chlorophyll readings were done using a portable meter and also the measurement of plant height. Plants were cut near the surface, roots were washed and the nodules were detached and counted. After that, it was determined the dry weight of plant roots, nodules, and shoots. Soybean fertilization with poultry litter increases the chlorophyll content of leaves, plant height, shoot dry matter, root dry matter, and nodulation. The use of poultry litter on soybean favors its growth with decreasing increments, except for root dry matter, and with an optimum dose for each variable. The supply of poultry litter can replace mineral fertilizers in terms of soybean growth.

ADUBAÇÃO NITROGENADA PARA MILHO SAFRINHA EM SUCESSÃO À CULTURA DO FEIJOEIRO

O nitrogenio e um dos nutrientes limitantes para a cultura do milho, o elemento extraido em maior quantidade e o que mais onera o custo de producao. O objetivo com este trabalho foi avaliar epocas de aplicacao e parcelamento do adubo nitrogenado em cobertura para a cultura do milho safrinha, em sucessao a cultura do feijoeiro, na regiao de Jatai, GO. Utilizou-se o delineamento em blocos casualizados com quatro repeticoes. Os tratamentos avaliados foram:adubacao em cobertura no estadio V1; no estadio V6; parcelamento nos estadios V4 e V10; estadios V4, V6 e V10 e uma testemunha sem nitrogenio em cobertura. As caracteristicas avaliadas foramclorofila no estadio VT, altura de plantas e de espiga, diâmetro de colmo, numero de fileiras por espiga, numero de graos por fileira, numero de graos por espiga, diâmetro de sabugo, diâmetro de espiga, massa de mil graos e produtividade. Procedeu-se ainda a uma analise economica dos resultados obtidos. O parcelamento da adubacao nitrogenada nas condicoes estudadas influenciou apenas a clorofila foliar e o diâmetro do colmo. Economicamente, a nao aplicacao de nitrogenio em cobertura foi a melhor opcao para esse ano agricola, mas os riscos e a reducao no diâmetro do colmo podem nao justificar o uso dessa estrategia.