Teores e aporte de nutrientes na serapilheira de Pinus taeda L., e sua rela??o com a temperatura do ar e pluviosidade

摘要

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.