According Wahono (2002: 3), degraded land is land that is already no longer function as a regulator of the media regulator of the water system, the element of agricultural production, as well as elements of the protection of nature and environment. Degraded land is a land that has undergone soil conditions or in the process of physical, chemical or biological ultimately endanger hydrological function, orologi, agricultural production, housing and social and economic life in the surrounding area of influence (Ade Iwan Setiawan, 1996: 19).
Land rehabilitation is an attempt to repair, restore and improve the condition of damaged lands in order to function optimally both as an element of production, media regulator the water system, as well as an element of protection of nature and environment (Wahono, 2002: 3). According to the Act – Law of the Republic of Indonesia Number 41 of 1999, Land and Forest Rehabilitation is intended to restore, maintain and improve the function of forest and land carrying capacity, productivity and role in supporting keidupan system is maintained.
Forest and Land Rehabilitation activity diselengaarakan through reforestation activities, Greening, Maintenance, Pengayan plants, or the adoption of soil conservation engineering vegetatively and civil technically on marginal lands da unproductive. According Supriyanto (1996: 1) Reforestation and afforestation in general do on degraded soil and the former logging areas. Both of these activities require seeds in large quantities and of good quality.
Selection of cover crops for land rehabilitation is based on its function, namely:
– Generate numerous forage materials and becrkadar N high (2-6%), so that in a short time can occur dekomposi and can increase soil organic matter content
– Increase soil biological activity that directly improve soil structure and aeration
– Protecting the land from the destructive force of rainwater that causes erosion; and
– Can binding element N from the air so that the need for synthetic fertilizers like urea can be suppressed.
Some cover crops that have been tested and have good prospects are Centrocema pubescen, Pueraria javanica and Pueraria phaseloides. For bare soil or nearly bare ground only need to be processed within 20 cm wide strips with a distance between lines 1 m. Seeds Centrocema deployed in rows, dennga TSP fertilizer as much as 50 kg / ha seed Centrocema required about 15 kg / ha. For land that is overgrown with reeds two weeks before processing the soil needs to be done spraying with Roundup herbicide or Dewpont.
After a cover crop one year old have usually been formed litter is thick enough so that the land is ready to be replanted. Cover crops are then cleared up on the ground surface, and then stocked in the land surface as a mulch. Combustion of the residual dry ground cover that has resulted in the rehabilitation efforts that have been made to be in vain. As known pembakalan lead to a variety of nutrients N losses quickly evaporates rapidly available K fertilizer despite the disruption of biological activity but also so that the slower the structure formation.