Organic acids exudates and enzyme activities in the rhizosphere based on distance from the trunk of oil palm in peatland
2017
Maswar | Sutandi, Atang | Sabiham, Supiandi | Harianti, Mimien | Saraswati, Rasti
Enzyme activity in oil palm rhizosphere could be used as a quality indicator of peatland. Roots play an important role in producing exudates of organic acids that are deposited in the rhizosphere. This research aims to study root exudates and enzyme activities in oil palm rhizosphere based on the distance from the tree trunk. The research was done in an oil palm plantation at Koto Gasib, Siak District, Riau Province, Indonesia (0.74°–0.77° N and 101.77°–101.74° E) using the explorative method. The observation of oil palm rhizospheres was done by dismantling the root zone of the selected oil palm tree trunk. Oil palm root was collected at distances of 0–1, 1–2, and 3–4 m from the tree trunk while the adhered peat samples were taken at the surface layer of 0–25 cm depth within a quarter circle area of the canopy. The results showed that enzyme activities in oil palm rhizosphere decreased with increasing distance from the tree trunk. This decrease is attributed to the increase in organic acid root exudates and water content and a decrease in soil pH. Thickness of peat did not influence enzyme activity and organic acid content. Enzyme activities in the rhizosphere of severely degraded forest and shrubs were lower than those in oil palm rhizosphere. The organic acid exudates in the rhizosphere of oil palm, forest and shrubs consisted mainly of aliphatic compounds. Fertiliser application at 1–2 m from oil palm trees decreased organic acid content in the exudates. Results from this study also showed that the large N uptake by plants mainly originated from fertiliser application. Thus, nutrient supply for oil palm growth originated from fertiliser application rather than from peat decomposition.
显示更多 [+] 显示较少 [-]