Agricultural waste composting: a source of humic substances

Faced with a scenario where the sustainability is increasingly sought, the waste composting plays a key role in the recycling of organic waste from agriculture. Waste composting is the process of decomposition of organic matter by microorganisms under controlled conditions forming a biologically stabilized final compound. This organic compound can be used in soil to improve its physical, chemical and biological characteristics. Humic substances are complex molecules produced in this transformation process of organic matter and they contribute to the regulation of important ecological and environmental processes. In this review, we will comment the main aspects of the waste composting and the main activities of the humic substances in plants

Use of light-emitting diode (LED) in the physiology of cultivated plants – review

The objective of this study was to demonstrate the effects of the use of LED bulbs in the physiology of cultivated plants. Light-emitting diodes (LEDs) have been proposed as a light source for controlled environments or in plant growth chambers, since they have desirable characteristics for plant development. The development and physiology of plants are strongly influenced by the environment light spectrum provided by the LEDs, among which we can mention the blue, red, green, and their combinations. The blue light, for example, is responsible for a number of important photomorphogenetic features in plants, including stomatal control. Studies indicate that the red wavelength is efficiently absorbed by the pigments present in the plants, since its wavelength is very close to the absorption peak of chlorophyll. The relevance of green light responses is based on the assumption that there are situations in nature that the plant may find conditions of increased green radiation in its growing environment. LED bulbs offer many advantages as radiation sources for plants, but there are difficulties that delay their implementation for applications in the plant cultivation. With the advancement of technologies, the characteristics and performance of LED bulbs, as a source of radiation for plants, tend to be improved. However, this efficiency varies among the light spectra and the species. Thus, the advancement in the use of LEDs in the protected cultivation of cultivated plants is linked to specific physiological responses of each species