Revista Árvore (Feb 2010)
Teores e aporte de nutrientes na serapilheira de Pinus taeda L., e sua relação com a temperatura do ar e pluviosidade Contents and input of nutrients in Pinus taeda L. Litter related to air temperature and rainfall
Abstract
O objetivo deste estudo foi avaliar os teores e o aporte de nutrientes ao piso florestal num povoamento de Pinus taeda L. e sua relação com a temperatura do ar e pluviosidade, implantado em área anteriormente ocupada por campo nativo, na cidade de Cambará do Sul, RS, através da queda de serapilheira, avaliado durante um período de três anos, contados a partir do quinto ao sétimo ano de idade do povoamento. A serapilheira foi coletada mensalmente através de coletores de 1,0 m² (1,0 x 1,0 m), durante o período compreendido de abril/2004 a março/2007. Após cada coleta, as amostras de serapilheira foram analisadas quimicamente, quanto aos teores de macro e micronutrientes. Os teores de K, Mg e Cu correlacionaram-se positivamente (p The objective of this study was to evaluate the contents and input of nutrients to forest floor in a Pinus taeda L. stand and the relation with rainfall and air temperature, in an area previously occupied with native grass, in Cambará do Sul, RS, through litterfall, evaluated during a three-year period, from the 5th to the 7th year of the stand. Litter was monthly collected in 1.0 m² (1.0 x 1.0 m) collectors, from April/ 2004 to March/2007. After each collection, litter samples were chemically analyzed for macro and micronutrients. The contents of K, Mg and Cu showed a positive correlation (p < 0,05) with air temperature, while Fe (p< 0.01), Mn and Zn (p < 0,05) showed a negative correlation with this climatic variable. The contents of N and K showed a negative correlation (p < 0.01 e p < 0,05, respectively). The contents of K, Mg and Cu showed a positive correlation (p < 0,05) with rainfall and the contents of S showed a positive correlation (p < 0,05) with air temperature, while the contents of Fe (p < 0.01), Mn and Zn (p < 0,05) showed a negative correlation with this variable.The contents of N and K showed a negative correlation (p < 0.01 and p < 0,05, respectively) with litter amount monthly deposited. Macronutrient mean annual input to soil, through litter deposition, in kg ha-1 was: 18.8 of Ca; 13.0 of N; 3.0 of Mg; 1.6 of K; 1.3 of S and 1.1 of P and for micronutrients the transference, in g ha-1 was: 4,708.3 of Mn; 592.3 of Fe; 74.1 of Zn; 34.0 of B and 7.6 of Cu. The results demonstrate the importantance of keeping the litter over the soil to maintain nutrient cycling.
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