Interações entre microclima, parâmetros de crescimento da planta e informações espectrais em cultivo de milho irrigado sob plantio direto

• Autor(a) principal: Silva, Marcos Antonio Vanderlei
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1494
• topic: Milho; Análise de crescimento; Radiação fotossinteticamente ativa; Índice de vegetação; Corn; Growth analysis; Active photosynthetically radiation; Vegetation index; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::AGROMETEOROLOGIA

By the nutritive value, the maize (Zea mays L.) is one of the most widespread grain in the world, with great social and economic importance. In Brazil, about 14 million hectares, is the most widely planted crop, representing 30% of the agricultural area of the country. The yield of grains in Brazil and in Minas Gerais State is around 3652 kg ha-1 and 4341 kg ha-1, respectively, well below the desired values, considering its production potential, which, with the use of high technology, beyond 16,000 kg ha-1. However, the corn crop is experiencing significant advances in several fields of science agronomic, enabling better understanding of the production process and its interactions with the environment, which has generated significant increases in productivity. Despite of complexity of the production system, agriculture seeks to understand it to maximize the productivity of crops. However, to succeed, they require knowledge and understanding of the factors that affect the physiology and hence the productivity of plants. From thesepropositions, this paper aimed to study the behavior of ecophysiological indicators at different stages of corn grown under no-till depending on the microclimatic variables and spectral indices, characterizing the micro climate of the culture, and assess biomass estimates based on these indices. The experiment was conducted at the experimental area of Embrapa Milho e Sorgo in Sete Lagoas-MG, with the variety BR 106, grown under no-tillage. To mark out the analytical process of growth quantitative analysis of the phenological stages were divided into four periods: P1 (emergency-8 sheets), P2 (12-leaf Flowering), P3 (dolly bubble formation water) and P4 (Grand milky-Physiological Maturation). The growth of the BR 106 was affected by changes in the microclimate of the canopy, which were characterized by extended periods of cloudiness, reducing the potential for vapor in the atmosphere and fluctuations in the energy, especially light and air temperature, thereby ensuring that the maximum the main attributes ecofiological growth were observed in P2. However, the senescence of leaves below the middle third, more significant in the transition from P2 to P3, increased RAF (leaf area ratio) and SLA (specific leaf area) and reduce the RLM (ratio leaf matter) dependent LAI (leaf area index), CGR (crop growth rate) and NAR (net assimilation rate), which led to a 13% decrease in the assimilation of CO2 over the reproductive period. This behavior of the ratings and did not affect the grain yield of the BR 106 that had a value close to potential. The accumulation of PARI (photosynthetic active radiation intercepted) had satisfactory relationship with biomass production and accumulated dry matter air can be a suitable parameter to quantify the biomass production of BR 106, using the coefficient "a". The responses morphophysiological and physiological in relation to environmental variables, in terms of growth, and strong correlations have been proven by the associations between groups established by canonical correlation. Using the estimate of leaf conductance as a function of PAR (photosynthetic active radiation), an indicator of gas interaction may be important in monitoring the growth of the BR 106, as reported behavior by analyzing correlation with environmental factors such as light, CO2 and temperature and VPD (vapor pressure deficit). Finally, the estimate of DMa (dry matter aerea) through the Monteith model, considering the vegetation indices derived from the relationship with the IAF, when evaluated through statistical indices showed good precision and good accuracy according to model agreement Willmott. Whereas the index "c" of confidence, the results for the MSa estimated by NDVI (Normalized Difference Vegetation Index) and SAVI (vegetation index adjusted for soil), using the band 1 and 2 of the product MOD09GQ showed performance within the criteria of "good" and is therefore applicablefor use in simulation growth of corn, which have as input for the IAF, to climatic conditions, moisture and management studied.