Respostas bioquímico-fisiológicas e agronômicas em alface e milho em função da aplicação de „água de xisto‟.

Abstract

Historically, the aim of agronomic efforts has been focused on yield, using fertilizers that, due to the production processes, have become increasingly free of trace elements and micronutrients, limiting the demand for plants, causing soil depletion, and consequently, limiting the quality of crops. Thus, the search for foliar supplementary fertilizers, able to biofortify crops and to deal with plant micronutrient deficiency, has been the subject of several studies. In this context, the water extracted from shale rock (shale water) throughout the pyrolysis process to obtain fuel oil and other products represent an environment safety alternative. In this study, shale water was characterized physical-chemically and evaluated the security and potential of its use in agriculture delivered with or without micronutrient enrichment. The results showed a great variety of organic compounds, mineral nutrients and trace elements in this by-product, which represent a complex matrix that could be of interest for plant nutrition and induction of primary ans secondary metabolisms. The foliar application of different doses of shale water in lettuce showed an absence of toxic contaminants, indicating its security to use in food production. Furthermore, the increase on yield and in certain nutrients in lettuce as well as the improvement of maize plants growth and grains yield and quality, including primary and secondary metabolites, were also observed by the foliar application of shale water. The enrichment with micronutrients also shows improvements on yield, amino acids content as well as of some minerals accumulation in maize grains. However, micronutrient supplementation did not increase carotenoids content, suggesting that shale water could be used in agriculture without de necessity of enrichment, representing an appropriate alternative to provide nutrients and biofortify crops.