ABSTRACT
In the agricultural sector, companies involved in the production of plastic greenhouses are currently searching for a suitable covering adapted for every climate in the world. For this purpose, this research work has determined the chemical, radiometric and mechanical properties of 53 polymeric films samples from Europe and South America. The chemical tests carried out with these samples were elemental analysis (C, H and N) and FT-IR spectrometry. The radiometric properties here studied were the transmission, absorption and reflection coefficients along the spectrum between 300 and 1100 nm. For the mechanical properties, tensile strength, tear strength and dart impact strength, tests were carried out. Finally, all these data were collected, and a multivariate statistical analysis was carried out using the SPSS statistical to group the samples into statistical groups adapted to specific climatic regions. The elemental analysis and FT-IR spectrometry allowed group the samples into nine groups. The samples were grouped according to their chemical (elemental analysis), radiometric and mechanical properties by multivariate analysis. The dendrogram separated five very different groups in terms of number of samples. These groups have specific chemical, radiometric and mechanical characteristics that separate them from the rest. These groups make it possible to narrow down the applications and correlate with the radiometric properties to see in which geographical area of the world they are most effective in increasing yields and achieving higher quality production.
ABSTRACT
Borage is a well-known plant of great importance in human nutrition and health. Expanding knowledge of particular plants that have anti-cancer products is a global concern. There is substantial information regarding the benefits, presence and extraction of gamma linolenic acid (GLA; 18:3n6) in different plants around the world, especially in borage seeds. However, there is little information concerning the effects of the salinity of the nutrient solution on the growth and presence of GLA in borage seeds. The objective of this work was to determine the optimal salinity of the nutrient solution for obtaining GLA in soilless cultivation systems. Borage plants were grown in coconut fibre and provided three treatments of nutrient solution of 2.20, 3.35 and 4.50 dS m-1, increasing solution salinity with the standard nutrient solution of concentrated macronutrients as a reference. Vegetative growth, seed production and GLA ratio were measured. The results of vegetative development and GLA production doubled and tripled with the increase in salinity of the nutrient solution, respectively.
Subject(s)
Borago/growth & development , Plant Oils/metabolism , Seeds/growth & development , Soil/chemistry , gamma-Linolenic Acid/metabolism , Borago/metabolism , Electric Conductivity , Seeds/metabolismABSTRACT
ABSTRACT: The irrigation water consumption of a soilless cucumber crop under greenhouse conditions in a humid tropical climate has been evaluated in this paper in order to improve the irrigation water and fertilizers management in these specific conditions. For this purpose, a field experiment was conducted. Two trials were carried out during the years 2011 and 2014 in an experimental farm located in Vinces (Ecuador). In each trial, the complete growing cycle of a cucumber crop grown under a greenhouse was evaluated. Crop development was monitored and a good fit to a sigmoidal Gompertz type growth function was reported. The daily water uptake of the crop was measured and related to the most relevant indoor climate variables. Two different combination methods, namely the Penman-Monteith equation and the Baille equation, were applied. However, the results obtained with these combination methods were not satisfactory due to the poor correlation between the climatic variables, especially the incoming radiation, and the crop's water uptake (WU). On contrary, a good correlation was reported between the crop's water uptake and the leaf area index (LAI), especially in the initial crop stages. However, when the crop is fully developed, the WU stabilizes and becomes independent from the LAI. A preliminary model to simulate the water uptake of the crop was adjusted using the data obtained in the first experiment and then validated with the data of the second experiment.
RESUMO: Com o objetivo de melhorar a gestão da água de irrigação e fertilizantes em condições específicas, foi avaliado, neste trabalho, o consumo de água de irrigação de pepinos cultivados sem solo em casa de vegetação. Para avaliar este efeito, conduziu-se um experimento de campo. O trabalho de pesquisa foi composto de dois ensaios realizados durante os anos de 2011 e 2014 em Vinces (Equador), onde predomina o clima tropical. Em cada ensaio, avaliou-se o ciclo de crescimento completo da cultura do pepino cultivada em estufa.O desenvolvimento da cultura foi monitorado e um bom ajuste para a função de crescimento tipo sigmoidal Gompertz foi encontrado. A absorção de água diária da cultura foi medida e relacionada às variáveis climáticas mais relevantes. Com o objetivo de modelar o consumo de água das culturas, dois métodos de combinação diferentes, isto é, a equação de Penman-Monteith e a equação Baille, foram aplicadas. No entanto, os resultados obtidos com estes métodos de combinação não foram satisfatórios devido a fraca correlação entre as variáveis climáticas, especialmente, a radiação incidente e absorção de água pela cultura (WU). Por outro lado, foi encontrada uma boa correlação entre a captação de água da cultura e o índice de área foliar (LAI), especialmente, nos estágios iniciais da cultura. No entanto, quando a cultura está completamente desenvolvida, o WU estabiliza e torna-se independente do LAI. Um modelo preliminar para simular a absorção de água da cultura foi ajustado e utilizado e, os dados obtidos do primeiro experimento foram comparados com os dados do segundo.
