The Centre for Applied Ecology "Prof. Baeta Neves" (CEABN InBIO), from the Institute of Agronomy (ISA), from the University of Lisbon in a protocol with the Infraestruturas de Portugal SA (IP) worked in a slope stabilization and landscape integration project, implemented in 2014, at Malveira junction of A21 highway in Portugal.

Several landslides and deep gully erosions characterized the slope, 40m high and 250m of base, divided in three steps, with no vegetation. The project joined usual geotechnical solutions, as superficial drainage and slope reshaping, with soil bioengineering technics, to achieve a new slope configuration covered by new vegetation, to avoid rock falling on the road and future erosions. The project aim was to implement soil bioengineering techniques, some of which have not yet been applied in Portugal, like a pilot project on a new soil with a new geometric slope configuration, without any humus available.

These techniques were planned and implemented to:

• Protect slopes from superficial erosion:

- Sowings with straw mulch and straw mat;

- Hydroseedings;

- Hydroseedings on geogrid.

• Stabilize slopes:

- Hedge brush layers;

- Shrub planting.

• Consolidate slopes:

- Live gabions;

- Live wooden check-dams.

• Protect from erosion temporary water runoffs:

- Live rough bed channels;

- Live combs;

- Live mattress.

Plants, cuttings and herbaceous species defined in the project plan were chosen based on tests carried out by CEABN InBIO, with plants of the mainland Portugal flora. CEABN InBIO cooperated with the IP in the project management during the execution and nowadays is in charge of its monitoring. Project implementation was planned to start in September 2013 in order to have a better period for the soil bioengineering constraints. However the effective start was in February 2014, whereby the project work plan had to be redefined considering this delay.

Actually the soil bioengineering project was implemented in the worst period of the year for this kind of works. Despite this delay, sowings with straw mulch and mat made in June and July, never irrigated, were able to produce seedlings already in July, which gave rise with September rains, to a dense herbaceous cover by all over the slope, reaching its green best aspect in the period between November and March. Cuttings used in other techniques were installed between May and July. It was decided to irrigate these cuttings with drip watering, until September to avoid their death. Rooting of cuttings installed in live gabions and in live wooden check-dams had a great success. However, some of the cuttings, installed at the end of July, died so they are going to be substituted in the next winter. Also the hedge brush layers, implemented in July, had a drip watering until September. Within this layer were used cuttings and small shrub plant with root-ball, installed with buried stems, creating dense shrub vegetation barriers. Between the hedge brush layers was also performed two hydrossedings, executed in September and repeated in December 2014. Some of these seeds didn’t remain pasted to the soil, getting trapped in the hedge brush layers and contributing in this way to create denser green barriers.

An eroded and instable slope, with imminent risk of falling rocks on the road, is now replaced by a new one. Junction construction in 2008 created a landscape disrupted, that today new highway manager tries to improve with the construction of a new, functional, and green landscape. The Project was already visited by students from the Escola Superior Agrária de Viseu and also by Palermo University students. Also is already planned another technical visit of students from the Lisbon University (Instituto Superior Técnico and Instituto Superior de Agronomia) and from the Algarve University.