Plantas herbáceas nativas do Brasil para controle da erosão do solo

Abstract

Erosion is one of the main processes that leads to soil degradation and is considered one of the major environmental problems on a global scale. Nature-based solutions (NBS) are important tools to mitigate and restore soil affected by degradation processes. The role of vegetation in protecting soil from erosion has long been recognized. However, the effectiveness of plants in controlling erosion depends on their functional traits, both above and below ground. Thus, the selection of suitable species to control soil erosion should be made based on knowledge of their morphological and functional traits, ecological, reproductive, socioeconomic, and cultural aspects. The main objective of this work was to investigate the functional and ecological traits of native Brazilian herbaceous species and their potential to control erosive processes, and for that, it was divided into three studies. The herbaceous species selected for these studies were Axonopus affinis Chase, Alternanthera philoxeroides (Mart.) Griseb., Arachis pintoi Krapov. & W.C. Gregory, Paspalum notatum Flüggé, Paspalum plicatulum Michx., Sphagneticola trilobata (L.) Pruski and Tripogandra diuretica (Mart.) Handlos. The study 1 was conducted in rhizobox containers in a greenhouse with the objective to investigate and compare the morphological characteristics of native Brazilian species and their growth strategies and nutritional demands, as well as to evaluate their potential to reduce soil erosion and sediment trapping. The study 2 was conducted in an experimental area in the city of Santa Maria-RS, where seedlings of the seven species were planted in 1.5m x 1.5m plots. The objectives of this study were to evaluate the cover index and the development of the species and to investigate the functional traits of the root system by a non-destructive method at two seasons of the year. The study 3 was carried out in the laboratory, in which samples with plants propagated in the greenhouse were submitted to the Inderbitzen test to evaluate the effectiveness of the species in reducing soil loss rates during concentrated flow and to determine the relationship between plant functional traits and soil loss rates. The results obtained in these studies demonstrate that all species, to a greater or lesser degree, are able to control the erosive processes. However, it was evident that there is a wide variation in the plant functional traits and that these traits are influenced by environmental factors, which proves the importance of knowledge of the functional traits of each specie and their ecological aspects to choose the most appropriate ones for each location and type of intervention. Thus, it is suggested the use of a mixture of species in projects that aim to control soil erosion, contributing not only to greater protection and soil stability, but also to increase the diversity of species and ecosystem balance.