Suhardi Suhardi
University of Bengkulu

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PENGARUH PENGGUNAAN TANAH GAMBUT SEBAGAI LAHAN PERTANIAN TERHADAP PERUBAHAN POLA LAJU MINERALISASI NITROGEN Suhardi Suhardi
Jurnal Ilmu-Ilmu Pertanian Indonesia Vol 7, No 2 (2005)
Publisher : Program Studi Ilmu Tanah Fakultas Pertanian UNIB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31186/jipi.7.2.104-110

Abstract

The objective of this research was to determine the change of peat nitrogen mineralization rate under influence of peat land transformation on land culture. Four types of peat land transformation were used in this study. They were : low intensive paddy field (STI), high intensive paddy field (SI), dry land crop (LKS), and palm oil plantation (LKT). Four parameters were used to measure the rate of nitrogen mineralized for this necessity : cumulative of nitrate mineralized (Nt), nitrogen mineraliztion potential (N0), half time of mineralization (Tc), and nitrogen mineralization coefficient (K). This research was carried out in laboratory by incubating followed by leaching the peat by using Stanford and Smith (1972) method. The research revealed that the highest intensity of nitrogen mineralization was reached during first to fourth weeks of incubation. On the other hand, the transformation of peat land to culture land enhanced the rate of nitrogen mineralized which was showed by decrease the value of N0 and Tc, while its K value increased. This research showed that control (undistubed peat land) had the highest value of N0 and Tc (44,094 me NO3 100 g-1 peat and 20,586 weeks) and the lowet K value (0,033 week-1); while the lowest of N0 and Tc values and the highest of K value was obtained by peat land that was transformed to dryland crop (GB7). 
PERUBAHAN PENUTUPAN LAHAN DAN PENGARUHNYA TERHADAP CADANGAN AIR PADA DAERAH TANGKAPAN AIR DANAU DUSUN BESAR Suhardi Suhardi
Jurnal Ilmu-Ilmu Pertanian Indonesia Vol 7, No 1 (2005)
Publisher : Program Studi Ilmu Tanah Fakultas Pertanian UNIB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31186/jipi.7.1.51-58

Abstract

The aim of this research was to determine the change of regions covered by vegetation in catchment area of Dusun Besar Lake. The research was conducted by analyzing Landsat TM Datas obtained in 1994, 1997 and 2003 and supported with field observation in 2003. Analyzed was conducted by using of Er Mapper 5.5 with RGB 542 bands. This research revealed that the decrease of regions covered by vegetation was observed from 1994 to 2003. The width of this area in 1994 was 2039.50 ha, while in 1997, this area became 1375.97 ha and decreased to 282.26 ha in 2003. The reduce of this region caused, undoubtedly, the shrink of areas covered by flood around lake site. In fact, this research showed the decrease of this flood area from 627.34 ha in 1994, and became 160.67 ha in 1997 and 44.29 ha in 2003. This reduction of vegetation area was probably due by high intensity of deforestation by resident who changed this area to became paddy rice or other types of land culture. This deforestation was intensified by road construction from Nakau to Air Sebakul in 1990 that split this area.