OIL PALM BIOMASS ASH IMPREGNATED WITH PHOSPHORUS IN Lactuca sativa CULTIVATION
Agro-industrial waste, fertility, phosphorus increasing
The need to recycle nutrients, reincorporating them into agricultural systems, and the proper destination of residues produced in agro-industries, demand studies to define the potential of these residues as soil conditioners. Oil palm ash (CPO) is an agro-industrial residue from oil extraction plants and has chemical quality that makes it a material with potential for use in agriculture. The by-product originates from the incineration of fibers, fruit and seed skins, in boilers with a firing temperature that varies from 450 to 1000 ºC. Burning is the fuel for the generation of steam used in the heating process of fresh bunches and, in some cases, the generation of electrical energy. The state of Pará is responsible for 97% of the Brazilian production of palm oil, which means a significant production of CPO. It was studied the effect of ashes impregnated or not, with different sources of P on the soil fertility and the residual effect, using the culture of lettuce (Lactuca sativa L.) as a test plant. The physical-chemical characteristics of the ashes, the fertility of the soil after application and the growth of the alaface were evaluated. The two ashes showed similar results in terms of pH and electrical conductivity, while C1 (400 to 500 oC) had a higher CTC (1386.82 cmol g-1) and C2 (± 800 oC), a higher particle density (0.396 g cm-3). Significant total levels of P, K, Ca, Mg, Mn, Mo, Cu, Zn and B were observed, with C2 being richer in nutrients. Both CPO increased inorganic carbon and the application of C1 increased organic carbon and presented a higher CTC. It was observed that the ash has a neutralizing power for the exchangeable Al, raised the pH and reduced the potential acidity, in addition to increasing P, K, Ca and Mg to the soil.