Quality improvement of compost from oil palm empty fruit bunch by addition of boiler ash and its effect on chemical properties of red-yellow podzolic and mustard (Brassica juncea)

Abstract

Processing of oil palm fresh fruit bunch (FFB) to get crude palm oil (CPO) will produce some waste, among others is the oil palm empty fruit bunch (EFB). The EFB is abundantly produced in any plantations that without carefull handling will induce a problem to the environment. Some plantations have been using the EFB to produce compost. However, the quality of their compost from EFB is highly varies due to the use of different composting method. On the other hand, boiler ash of oil palm processing unit contains various and significance chemical elements that can be used to chemically improve the quality of EFB compost. This research was aimed to study: 1) the difference in quality of EFB composts produced by different composting methods, before and after addition of boiler ash, and 2) the influence of boiler ash-enriched EFB compost to chemical properties of Red Yellow Podzolic and mustard productivity. Each of EFB compost produced by opened method (K1) and by closed method (K2) were treated with four levels of boiler ash doses (A0 = 0%, A1 = 5%, A2 = 10%, and A3 = 15%). Both of materials are mixed and incubated for 2 weeks. Then boiler ash-enriched EFB compost were mixed with soil (compost : 20% and soil : 80% by volume) and used as medium to grow mustard in green house experiment. The experiment was designed in completely randomized design with 9 treatments and 3 replications. The treatments were comprise of control, K1A0, K1A1, K1A2, K1A3, K2A0, K2A1, K2A2 and K2A3. The results showed that the addition of boiler ash into EFB compost increased pH from 7,0 to 7,4-7,8 for K1 and from 7,6 to 7,7-7,8 for K2. The increase of compost pH was in accordance with the increase of boiler ash dose. Whereas macro and micro nutrients content was not influenced by the addition of boiler ash. Boiler ash-enriched EFB compost increased pH of Red Yellow Podzolic. K1 did not influenced C-organic, P-available, K-exchangeable, Ca-exchangeable and Mg-exchangeable content of Red Yellow Podzolic. In contrast, K2 increased P-available, K-exchangeable and Ca-exchangeable of Red Yellow Podzolic. Beside that, boiler ash-enriched EFB compost increased growth, yield and N, P, K, Ca, Mg content of mustard. The yield of mustard increased about 173,5% – 226,5% for K1 and 279% – 290% for K2 compared to control (68 g/plot).