<span lang="IN">One of the efforts to solve the decreasing of agriculture land area caused by land use change </span><span>is through</span><span lang="IN"> agroforestry system (AF), such as the cultivation among the Albizia chinensis trees. This research, along with the experiment, aims</span><span> at </span><span lang="IN">study</span><span>ing</span><span lang="IN"> the light characteristic of 1.5 years old</span><span lang="IN">Albizia c and the effect of fertilization on the growth of soybean</span><span> and</span><span lang="IN"> test</span><span>ing</span><span lang="IN"> the soybean yield of Dega 1 varieties in agroforestry system based on Albizia c. </span><span>Using the</span><span lang="IN"> split-plot Randomized Block Design (RBD)</span><span> as the experiment</span><span lang="IN">, the intensity of light was</span><span> employed as</span><span lang="IN"> the main plot</span><span> whereas </span><span lang="IN">the fertilizer was </span><span>used as </span><span lang="IN">the subplot</span><span> in this study</span><span lang="IN">. There were four levels of light intensity: land with high light intensity (lands outside AF), rather high light intensity (radiation transmission fraction (RTF) among Albizia c 1425 ha<sup>-1</sup> density), medium-high light intensity (RTF among 2850 Albizia c density with pruned canopy), rather low light intensity (RTF among 2850 Albizia c density with unpruned canopy). As the subplot were some various fertilizers such as Albizia c litter, Albizia c litter + phosphorus (P) + potassium (K), and without any fertilization. </span><span>Totally </span><span lang="IN">12 treatments </span><span>were </span><span lang="IN">obtained</span><span> and</span><span lang="IN"> each of </span><span>those</span><span> <span lang="IN">treatments was replicated three times, consequently</span></span><span> consisting of </span><span lang="IN">36 experiment units. The result of this research shows that Albizia c was exceedingly potential for the soybean cultivation with AF system. The passing light under the canopy (RTF) depended on the distance between each tree and could be improved by pruning the canopy. The increasing RTF increased vegetative and generative growth. The </span><span>highest soybean</span><span> <span lang="IN">production (3.3 tons ha<sup>-1</sup>) could be achieved in 2850 trees ha<sup>-1</sup> density with pruned canopy (RTF: 49% equals to 28440 lux) compared with biomass production in open land (3.9 ton</span></span><span>s</span><span lang="IN"> ha<sup>-1</sup>).</span>