ABSTRACT
A study was conducted to find out the effect of fertilizers on the Biological Nitrogen Fixation (BNF) and seedling growth of some potentially important agroforestry tree species of Bangladesh in the nursery. Three different types of experiments were performed during the present study. In first experiment, Biological Nitrogen Fixation (BNF) and seedling growth of Albizia chinensis, A. saman, A. lebbeck, A. procera, Acacia auriculiformis, A. nilotica, A. tortilis, Sesbania sesban, Gliricidia sepium and Leucaena leucocephala were evaluated under nursery conditions by sowing the seeds in polybags filled with the mixture of soil and sand (1:1) and treated with different fertilizer treatments [@40kg urea ha-1, 80 kg urea ha-1, 40kg TSP ha-1, 80kg TSPha-1, (40kg urea + 40kg TSP) ha-1 and (80kg urea + 80kg TSP) ha-1] after one month of seed germination. The second experiment was conducted with six months old nursery raised polybag seedlings of six selected leguminous agroforestry species, namely Acacia auruculiformis, Albizia lebbeck, A. chinensis, A. saman, A. procera and Pongamia pinnata. Six seedlings of each species were selected, the three was kept as control and the rest three were treated with fertilizers (@80kg TSP ha-1). In that way four groups of each species were formed and each of the group was harvested at every 20 days interval. In the third experiment, five leguminous species namely Acacia mangium, A. hybrid, A. auriculiformis, Albizia lebbeck and Leucaena leucocephala were raised in nursery conditions by sowing the seeds in polybags filled with different growing media namely pure sand, pure soil, soil: cowdung 1:1, 2:1 and 3:1.and then evaluated for BNF (nodulation) and seedling growth in that treatments (media).
The effects of different fertilizers (Urea, TSP and Cowdung) on seedling growth and nodulation were compared to that of the seedlings grown in unfertilized soil or sand (control). The results revealed that the seedling growth was enhanced significantly with the different fertilizer treatments. In some cases, the higher levels of fertilizers reduced the seedling growth.
The study also revealed that the nodulation in terms of nodule number was significantly inhibited by the application N fertilizer (Urea) and cowdung, while the same was increased significantly with the application of P fertilizer (TSP).
A study was conducted to find out the effect of fertilizers on the Biological Nitrogen Fixation (BNF) and seedling growth of some potentially important agroforestry tree species of Bangladesh in the nursery. Three different types of experiments were performed during the present study. In first experiment, Biological Nitrogen Fixation (BNF) and seedling growth of Albizia chinensis, A. saman, A. lebbeck, A. procera, Acacia auriculiformis, A. nilotica, A. tortilis, Sesbania sesban, Gliricidia sepium and Leucaena leucocephala were evaluated under nursery conditions by sowing the seeds in polybags filled with the mixture of soil and sand (1:1) and treated with different fertilizer treatments [@40kg urea ha-1, 80 kg urea ha-1, 40kg TSP ha-1, 80kg TSPha-1, (40kg urea + 40kg TSP) ha-1 and (80kg urea + 80kg TSP) ha-1] after one month of seed germination. The second experiment was conducted with six months old nursery raised polybag seedlings of six selected leguminous agroforestry species, namely Acacia auruculiformis, Albizia lebbeck, A. chinensis, A. saman, A. procera and Pongamia pinnata. Six seedlings of each species were selected, the three was kept as control and the rest three were treated with fertilizers (@80kg TSP ha-1). In that way four groups of each species were formed and each of the group was harvested at every 20 days interval. In the third experiment, five leguminous species namely Acacia mangium, A. hybrid, A. auriculiformis, Albizia lebbeck and Leucaena leucocephala were raised in nursery conditions by sowing the seeds in polybags filled with different growing media namely pure sand, pure soil, soil: cowdung 1:1, 2:1 and 3:1.and then evaluated for BNF (nodulation) and seedling growth in that treatments (media).
The effects of different fertilizers (Urea, TSP and Cowdung) on seedling growth and nodulation were compared to that of the seedlings grown in unfertilized soil or sand (control). The results revealed that the seedling growth was enhanced significantly with the different fertilizer treatments. In some cases, the higher levels of fertilizers reduced the seedling growth.
The study also revealed that the nodulation in terms of nodule number was significantly inhibited by the application N fertilizer (Urea) and cowdung, while the same was increased significantly with the application of P fertilizer (TSP).
