Afforestation techniques for Albizia lebbeck Linn. (Benth.) on degraded lands.
Studies were made on the depth of soil working and soil amendments required for successful establishment of Albizia lebbeck on torrent land with a thin loamy soil mantle over boulders and gravels of various sizes and shapes (which constituted 80% of the soil) at a site on the Selakui Research Farm of the Central Soil Water and Conservation Research and Training Institute at Dehra Dun, Uttar Pradesh, in 1992. Growth and survival of planted seedlings were measured over 2 yr, during which brushwood cuttings, weedings and hoeings were carried out. Mixing of 30% partially decomposed leaf litter with excavated soil (with boulders removed) in planting holes of 26 cm diameter gave significantly better height growth than refilling the holes with top soil and excavated soil. Growth in holes of 50 cm depth was comparable with that in 100 cm deep holes refilled with top soil or a mixture of leaf manure and excavated soil. Height growth was 105 cm in 50 cm deep holes and 129 cm in 100 cm deep holes but statistically similar at 2 yr old. It is inferred that in torrent lands, 50 cm deep holes refilled with excavated soil mixed with 30% partially decomposed leaf litter reduces the cost of soil working and gives good growth and establishment of Albizia lebbek.