Soil Working Technique for Afforestation of Ravine Land by Direct Seeding

An experiement to evolve a suitable technique of soil working. i.e., depth and mode of refilling of trenches for raising plantations of Acacia nilotica Ssp indica (Syn. A. arabica) by direct seeding in ravine lands was carried out at the Soil Conservation Centre, Chhalesar (Agra) from 1961 to 1965. The treatment of depth of trench, in the initial stage, did not affect the seedling mortality, height and collar diameter but it significantly affected these characters from the fourth year onwards. The trenches 61.0 cm in depth (D₂) proved superior to 45.7 cm (D₁) and 76.2 cm (D₃) deep trenches. The seedling mortality decreased while the growth-in-height and collar diameter increased with the increase in the water storage capacity of the trench as influenced by the type of refilling of trenches. Refillings in the form of Ridge-Ditch (F₁) and Raised-Mound (F₂) were not found to be suitable for the locality, whereas Sunken-Mound (F₃) gave better performances. The Double-Trench (F₄) system, compared to the other three treatments of refilling of trenches, impounded maximum quantity of water, retained it for 3 to 4 days thereby increased the availability of soil moisture to the seedlings during dry spell and thus exhibited minimum seedling mortality and maximum seedling height and collar diameter growth. Further, this technique is simple to practise and does not require subsequent maintenance. At the end of fourth year the interaction of D₂ × F₄ was found to be better closely followed by D₂ × F₁. The cost for "F₄," as against of "F_l" "F₂" and "_F3" were found to be in the ratio of 4 :8. It is concluded that under the climatic, edaphic and topographic conditions such as those of Jamuna ravines, the type of refilling is more important compared to the depth of the trench for successful seedling establishment and better growth.