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Evaluation of the throwing sowing of native forest species for recovery of degraded areas.

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Author(s):
Denis Faquim Araki
Total Authors: 1
Document type: Master's Dissertation
Press: Piracicaba.
Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
Defense date:
Examining board members:
Ricardo Ribeiro Rodrigues; Sergius Gandolfi; Adriana de Fatima Rozza
Advisor: Ricardo Ribeiro Rodrigues
Abstract

Through the sowing of native species of different ecological groups, it will be possible to raise information on the constitution, the growing and enrichment of the bank of seeds as possible practical of recovery of degraded areas, mainly aiming at: 1) the first covering of the ground; 2) the possible enrichment of the area (increase of the species number) with the direct sowing. The general objective of this work was to analyze the methodological viability of the artificial constitution of bank of seeds of native forest species, as strategy of recovery of degraded areas. This work had as objective specific: A) To study the potential species for use of direct sowing of native species in degraded areas, how much to the emergency of seedlings and if the number of individuals established after one year of the sowing is enough for forest occupation of a degraded area; B) to determine different conditions (treatments) of the throwing sowing of native forest species to increase the emergency of seedlings. Two experiments in different periods had been carried through in this work. The experiment "A" was installed in February of 2003, in a randomized blocks design with 36 treatments and 3 repetitions, resulting in 108 parcels in factorial project (3x2x3x2) objectifying to test 20 species forest, being 10 fulfillment groups and 10 diversity groups. The experiment “B" was installed in February of 2003 with a randomized blocks design and 4 treatments with eight repetitions, resulting in 32 parcels in factorial project (2x2) objectifying to test 20 forest pioneer species. In this experiment the seeds of the native forest species (20 species) beyond sown in the field had also its germination tested in nursery, for posterior comparison with the germination of the species in field conditions. In accordance with the gotten results the methodology revealed viable obtaining in the “A" experiment, to the 360 days after the sowing up to 874 individuals ha -1 of fulfillment groups (4 species) and 1.902 individuals ha -1 of diversity groups (7 species). The Platypodium elegans and Pterogyne nitens of fulfillment groups and of the diversity groups Jacaranda cuspidifolia had been the more distinguished in the experiment "A" with 292, 318, 574 individuals ha -1 respectively. Although the species in experiment "B" have not germinated in field conditions, its germination data in nursery had demonstrated that the seeds were viable, except Cecropia pachystachya. The ambient factors in field conditions had been the causers of this ungermination seeds of the studied forest species, mainly competition with Brachiaria decumbens. This results demonstrates that the handling of this grassy after-sowing is basic for the success of this methodology. (AU)