Effect of liming and fertilization on nutritional state and dry rubber production of rubber-tree

The effects of lime and NPK application on nutritional state and dry rubber production of clone RRIM 600 were evaluated. The experimental design was a randomized split-plot with four replicates. In the plots were tested two c ontrols (without fertilizer and without lime; without fertilizer and with l ime) and six treatments with lime and NPK fertilization (N1P1K0, N2P2K0, N1 P1K1, N2P2K1, N1P1K2 and N2P2K2). The two sub-treatments were the following tapping systems: 1/2S d/4 6 d/7 ET 2.5% LaPa 1/1 10/y (S1) and 1/2S d/6 6 d/7 ET 5.0% LaPa 1/1 10/y (S2). The NPK levels used, in kg ha(-1) y(-1), we re represented by 40 and 80 of N; 17.5 and 35.0 of P2O5 and 0, 33.2 and 66. 4 of K2O. There was a significant effect of treatments on the N, P, S, Cu a nd Zn content in leaves. The N applied to soil up to the second dosage was not enough to increase the N level in leaves. Increasing the application of K2O, in the presence of N2P2, promoted a linear decreasing effect on the Z n level. The highest rubber yield (1,778.9 kg ha(-1)), as an average of the three years, was obtained with the treatment N2P2K1 plus liming, under bot h tapping systems.