PERANAN HUJAN TERHADAP DINAMIKA HARA DI BAWAH TEGAKAN EUCALYPTUS UROPHYLLA. S. T. BLAKE DAN ACACIA MANGIUM WILLD.

Bambang Subali, Dr. Ir. Djoko Marsono

1988 | Tesis | S2 Ilmu Kehutanan

Penelitian ini bertujuan untuk mempelajari tentan, keseimban,an antara masukan dan keluaran hara di bawah te,akan Ellcal ptus urepbylla s.T. Blake dan Acacia ma­n(ium Willd. ????eserta aspek hidroloci,snya,yan, berkaitan den,an curah hujan. Penelitian ini dilakukan di Wanar;ama I Gunungkidul pada te,akan usia 3, 5 tahun den,an kemirin,an lahan 10%. Banyaknya masukan hara yan, teriawa air hujan sampai ke tanah di bawah lantai te,akan dan keluaran hara yan, ter????awa oleh aliran permukaan diukur berdasarkan 3 para-meter, yakni unsur N, P, dan K. Berdasar aspek keharaan, hasil penelitian menunjuk­kan bahwa selama 5 kali pen,amatan den,an curah hujan rata-rata 37,50 + 5,26 mm, masukan hara ke tanah di aa­wah kedua te,akaii jauh leaih ltanyak dari pada keluaran hara yan, terbawa oleh aliran permukaan, sedan'1tan di tempat terltuka menunjukkan basil yan, sebaliknya. Seja­uh aspek hidroloci,s yang dapat diamati, hasil!.peneliti­an menunjukkan 'bahwa selama 75 hari hujan den:;an curah hujan rata-rata 21,54 + 25,84 mm terdapat perbedaan yan, ierarti dalam hal air f:em"bus, aliran batan,, dan inter­sepsi tajuk kedua te,akan, tetapi tidak dalam hal inter­sepsi seresah dan aliran permukaan. Dibandinpcan den,an tempat terbuka, aliran permukaan di 11awah kedua te,akan jauh lebih kecil. Kedua macain te,akan bersama den,an curah hujan ikut memDerikan sumban,an terhadap banyaknya air tembus, aliran Datan,, dan intersepsi tajuk den,an pola linier, dan juca terhadap banyaknya intersepsi se­resah den,an pola logaritmik. Keti,a macam penutup la­han bersama-sama den,an curah hujan ikut memberikan sum­Dan,an terhadap banyaknya aliran permukaan, meskipun re­latif sedikit.

The purpese of this research is t• study about the Dalance between nutrient input ana output under Eucalyp­tus uronbylla ani Acacia man,ium stands with re,ard. to ra1nfall, and hydrolo,ical aspect at the two stands. This research was conductea en 3.5 year old stands in Wana,.ama I Gunun????dul at 10 % slope. The nutrient input carried •Y the rainfall te the soil under ' the standfleer and output carried •Y the surface runeff were measured, aased on the parameters of N, P, and K ele­ments. Based ????n nutrient aspect, the result showed that from 5 time observations with the avera,e rainfall 37.';A) + 5.26 mm, the nutrient input to the soil under the twe stands was ,reater than the nutrient output carried eut Y surface run•ff, while at the bare area showed the op­posite result. As far as the hydrolo'1cal aspect is concerned, the result showed that as lon, as 75 days ra­infall with the avera,e rainfall 21.54 + 25.84 mm it was found the si'11ificant differences in tb.rou,hfall, stem­flow, and canopy interception at the two stands, but not in litter interception and surface runoff. Compared with the bare area, the surface runoff under the two stands was much smaller. The two kinds of stand and the rain­fall take part in ????vin, contri•ution to the amount of throu,hfal.1, stemflow, and canopy interception with li­near pattern, and also to the amount of litter intercep­tion with 10,arithmic pattern. The three kinds of cover area and the rainfall take part in '1vin, contribution to the amount of surface runoff, althou,h it is relati­vely a l.i ttle.

Kata Kunci : Hara, TEGAKAN EUCALYPTUS UROPHYLLA. S. T. BLAKE, ACACIA MANGIUM WILLD.