Study on Land Rehabilitation at Mined Lands of PT Trubaindo Coal Mining, West Kutai, East Kalimantan

Abstract

In many cases, mined lands is not immediately ready to support plant growths due to bad drainages, soil structure disturbances, high temperature, uncontrollable overland flow, high erosion rate, lack understanding of suitable plant species, planting techniques and its maintenance. The study objective is to find out applicable design - procedure - techniques of mined-out lands revegetation to support and accelerate the ecological recovery of mined-out lands. Land revegetation is conducted by planting 10 trees species (3.000 seedlings) at mined-out lands after reclamation works. Plants species are selected based on previous studies and expected ecological function. Plant height, diameter, and growth performance are used as parameters associated with physical and chemical soil characteristics. The plant growth percentage is 93% with the lowest of Artocarpus champedens (84%) and the highest of Peronema canescens (86%) consecutively. Moreover, Terminalia catappa, Annona muricata, and Muntingia calabura show the strongest growth performance, while Shorea balangeran, Artocarpus champedens, Pterocarpus indicus are found weak. Soil is found being high compacted but no significant difference of fertility status between upper and lower layers, and also recognized being acid with moderate CEC and very high base saturation. Organic fertilizing reduces soil compactness, increasing soil porosity, CEC and its water content. Fertilizing of 100g NPK (16-16-16) stimulates biggest diameter and height increments of Shorea balangeran, Terminalia catappa, Annona muricata, Ficus variegata, Schima walichii. Moreover, Shorea balangeran, Entrolobium cyclocarpum, Terminalia catappa, Annona muricata, Ficus variegata, Schima walichii, Peronema canescens, and Muntingia calabura are still responsive to fertilizer application. Considering low nutrients contents, chemical fertilization are still needed to immediately increase macro nutrients content. Suggested dosage of NPK (16-16-16) fertilizer is 100 gr for Entrolobium cyclocarpum, Peronema canescens, Muntingia calabura, Terminalia cattapa, and Schima walichii; 150 gr for Annona muricata, Ficus variegata, Shorea balangeran; and 50 gr for Pterocarpus indicus and Artocarpus champedens. Simultaneously with revegetation works, the phenomenon of soil erosion potential dynamic is depend on influencing factors upon soil erosion occurences that are rainfall erosivity, soil erodibility, landform slope-lengths, vegetation cover, practical soil and water conservation. Vegetation growth cover is the most significant factor related with soil erosion dynamic at revegetated mined-out lands.