A global project on `Alternatives to Slash and Burn’ agriculture was initiated by a consortium of international and national research institutes to facilitate intensification of the use of converted forest land, in order to help alleviate poverty and protect the remaining forest areas for their biodiversity values and their role in mitigating greenhouse gas emissions. Data for the Indonesian benchmark areas in the lowland peneplain, piedmont and mountain zone of Sumatra are presented. A significant amount of forest land, especially in the lowland peneplain, has been converted in the last ten years into agricultural use, usually following logging concessions. Soils on the peneplain are poor (oxi-and ultisols) and current intensive crop based production systems are not sustainable. In the piedmont zone on better soils (inceptisols), rubber agroforests (still) characterize the area. Agroforests have emerged during the 20th century as the major alternative to slash-and-burn agriculture, based on a shift of emphasis from food crops to cash-earning tree crops. Emphasis on food crops, however continues in government resettlement schemes. Differences in organic C content of the topsoil between forests and crop land are about 0.5% C, with agroforests and tree crop plantations in an intermediate position. A new size-density fractionation scheme for soil organic matter demonstrated larger changes in light and intermediate fractions. Forest soils can be significant sinks for methane and thus partly compensate for the methane emissions in lowland rice production. Overall, the Sumatra benchmark areas demonstrate the need to combine intensification of land use at the field/household level with effective protection of remaining forest areas at the community level and reducing other driving forces of deforestation at the national level.
Tag: forest soils
Effect of growing medium on early growth and survival of Uaparka kirkiana Môell Arg. seedlings in Malawi
The use of appropriate growing medium has been an important factor influencing growth and survival of seedlings in the nursery. Raising Uapaca kirkiana rootstocks from seeds has been a challenge as pencil-size stem thickness is required before grafting can be done. An experiment was carried out with the objective of determining an effective growing medium that ensures survival and rapid growth of U. kirkiana seedlings. Ten different combinations of sand, forest soil and sawdust amended with four different levels of nitrogen, phosphorus and potash fertilizer were evaluated. The result showed that the growing medium comprising 75% forest soil and 25% sawdust produced the tallest seedlings with larger root collar diameter and higher survival at ten months after planting. Amending the same growing medium with fertilizer improved the root collar diameter of the seedlings. It is concluded that a growing medium comprising 75% forest soil and 25% sawdust and amended with NPK fertilizer was superior in improving U. kirkiana seedling growth to attain a suitable diameter for grafting within ten months.