Agronomical performance and profitability of exploitation systems in four rubber tree clones in São Paulo state

Abstract

The exploitation or tapping of the rubber tree, Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. Arg. is one of the most important cultural practices in determining useful life, yield and accounts for a major part of the total production costs in rubber farming. The objective of this work was to evaluate yield performance and economic aspects of rubber tree clones submitted to diverse tapping systems. The trial was placed in Guararapes city, São Paulo State, Brazil, in a randomized block design with split-plot in time. The plots consisted of the IAN 873, PR 261, RRI M 600 and RRI M 701 clones. The tapping systems consisted the subplots, where: ½S = tapping of half spiral cut; d/2, d/3, d/4, d/5 and d/7 = tapping every 2, 3, 4, 5 and 7 days, respectively; 11 m/y = tapping during eleven months per year; ET = ethephon (stimulant); Pa = panel application; La = lace application; 8/y = eight applications per year. The five experimental years were the sub-subplots and the ½S d/2 system was used as control. The analyzed variables were girth, dry rubber yield, tapping panel dryness and economic profitability. The ½S d/3 ET 2.5% and ½S d/4 ET 2.5% tapping systems provide the highest yield and profitability per hectare per year for the RRI M 600 and PR 261 clones. For the IAN 873 and RRI M 701 clones the yield superiority occurs in high tapping frequency; however the best profitability is obtained in the ½S d/7.ET 2.5% system.