The Effect of Omission Fertilizer Application on Rubber Yield of PB 260

Fertilizer application on mature rubber trees is sometimes neglected especially when the rubber price is low. The experiment to demonstrate the effect of fertilizer on rubber yiled was conducted for two years. The treatments impose were control, without fertilizer application, fertlizer application with straight fertilzer with general recommended dose and fertlizer applicakan with NPK tablet where the nutrient content were as much as 75%, 50%, 20% and 15% comapred with straight fertilizer. The experiment showed that the yiled was similar between control and fertilizer appplication during the first year observation, but at the secon year, continued fertilizer application gave better yield compared with control. The renewal bark thickness was also better in fertilizer appplication compared with control. The NPK tablet as much 75% Straight fertilizer gave he highest yield. This meant that NPK tablet is more efficent taken up by rubber tree comapred with straight fertilizer.