RESUMO: O objetivo deste trabalho foi avaliar a produtividade de butiazeiros ( Butia odorata ) em áreas de ocorrência natural sob a influência de diferentes habitats e agroecossistemas. Três áreas correspondentes aos Municípios de Barra do Ribeiro, Tapes e Arambaré, situados no Litoral Médio do Estado do Rio Grande do Sul foram selecionadas. Nessas áreas, foram distribuídas 11 parcelas de 25x100m² e avaliada a produção nas frutificações de 2008 e 2009. Em cada parcela, também foram avaliadas as condições químicas do solo, a elevação do terreno, a altura e a densidade de butiazeiros reprodutivos. As análises dos dados revelaram uma forte relação entre as condições edáficas e a produtividade dos butiazeiros. O butiazal de Tapes apresentou maior produção de frutos, resultante do aumento de cachos produzidos por planta, estando associada aos solos mais férteis e com maior disponibilidade de cálcio e magnésio. A menor produção de frutos foi relacionada com solos pobres em nutrientes, cobertos com pastagens de braquiária, assim como em planícies arenosas, com elevados teores de sódio. Mudanças nas características do solo, associadas com o habitat e o manejo, influenciam na produção de frutos de butiazeiro.

ABSTRACT: The objective of this study was to evaluate the fruit yield of naturally occurring populations of Pindo palms ( Butia odorata ) in different habitats and agricultural ecosystems. Three areas were selected in the municipalities of Barra do Ribeiro, Tapes and Arambaré, all of which are located on the Litoral Médio in the state of Rio Grande do Sul, Brazil. Eleven 25x100m² plots were selected in the aforementioned areas, and fruit yield was evaluated in the 2008 and 2009 seasons. Chemical conditions of the soil in each plot, elevation of terrain, height, and density of the reproductive Pindo palms were also assessed. Data analysis revealed a strong correlation between the edaphic conditions and the yield from the Pindo palms. Tapes Pindo palms exhibited higher fruit yield as a result of an increase in the number of bunches produced per plant, along with highly fertile soils and greater availability of calcium and magnesium. The lowest fruit yields were linked to nutrient-poor soils in Brachiaria pastures, as well as sandy plains containing high levels of sodium. Changes in the characteristics of the soils associated with habitat and management influenced the fruit yield of Pindo palms.

Tillage and fertilization methods may affect soil fertility. With the aim of assessing changes in soil chemical properties over a period of ten years, soil samples of a Paleudult were collected over nine seasons at three layer depths (0-5, 5-10, 10-20 cm) and were chemically analyzed. Grain yield and nutrient export in two summer crops, soybean (Glycine max) and corn (Zea mays), in a field experiment set in Eldorado do Sul, in the state of Rio Grande do Sul, Brazil, were determined. Three soil tillage systems were evaluated, conventional (CT), reduced (RT) and no-tillage (NT), combined with mineral (lime and fertilizers) and organic (poultry litter) fertilization. The no-tillage system stood out as compared to the others, especially in the surface layer, in terms of values of organic matter, soil pH, available phosphorus, cation exchange capacity and base saturation. Phosphorus content was higher under organic than mineral fertilization due to the criteria used for the establishment of fertilizer doses. Under organic fertilization, soil pH values were similar to those obtained in limed soil samples because of the cumulative effect of the organic fertilizer. Soybean yield was lower under NT in comparison to the RT and CT systems. Consequently, soybean grain exported a lower content of nutrients than maize grain. Maize yield was not affected by either tillage or fertilization systems.