Kandungan Unsur Hara dalam Daun Jati yang Baru Jatuh pada Tapak yang Berbeda

Abstract

Seresah di lantai hutan memegang peranan penting dalam menjaga produktivitas dan kelestarian hutan selain dapat mengendalikan erosi, mempengaruhi daur hidrologi dan unsur hara juga berfungsi sebagai penyimpan karbon. Kandungan unsur hara dalam seresah/daun sangat dipengaruhi oleh: spesies, genetik, bahan induk, tanah, dan iklim. Penelitian ini bertujuan untuk mengetahui kandungan unsur-unsur hara C, N, P, K, Ca, Mg, Na, Fe, Mn, dan Cu dalam seresah daun jati yang baru jatuh pada beberapa tapak. Sampel seresah (daun) diambil dari tanaman jati berumur 10 tahun, dari klon-klon unggul yang berasal dari tapak yang berbeda di Jawa. Analisis C dilakukan dengan metode Walkley dan Black dan N dengan metode Kjeldahl. Analisis P, K, Ca, Mg, Na, Fe, Mn, dan Cu dilakukan dengan mengekstrak sampel dengan campuran asam keras (HClO4 + HNO3), P terekstrak diukur dengan spektrofotometer sedangkan unsur logam dengan Atomic Absorption Spectroscopy (AAS).Hasil penelitian menunjukkan bahwa kandungan C tidak jauh berbeda berkisar 46,49-52,32%, sedangkan kandungan N dan P agak berbeda dengan nilai 0,52-1,28% dan 0,04-0,14%, sedangkan kandungan K, Ca, dan Mg agak berbeda secara berturutan mempunyai nilai 0,06-0,52%, 1,69-2,64% dan 0,10-0,45%, sedangkan Na hampir tidak berbeda berkisar antara 0,018-0,025%. Kandungan Fe dan Mn mempunyai perbedaan yang cukup besar berkisar antara 185-898 ppm dan 63-202 ppm, sedangkan Cu dan Zn tidak banyak berbeda berkisar antara 54-126 ppm dan 32-58 ppm. Hubungan antara kadar unsur yang bersifat mobile (C, N, dan P) pada seresah dan tanah tidak menunjukkan tren yang nyata, sebaliknya unsur yang bersifat immobile (K, Ca, Mg, dan Na) selalu konsisten antara kadar unsur hara di seresah dengan kadar unsur hara di tanah.Kata kunci: : jati, seresah daun, unsur hara, tapak, JawaNutrients content from new fallen leaves of teak from different sitesAbstractLitter on forest floor plays a very important role to maintain forest productivity and sustainability. The litter can control soil erosion, hydrology and nutrient cycles and has a function as carbon storage. The nutrients content in the leaf litter is affected by species, genetic, parent material, soil and climate. The objective of this research was to investigate the nutrient content of C, N, P, K, Ca, Mg, Na, Fe, Mn, and Cu in the litter from different sites. The newly fallen leaves samples were taken from the clonal teak plantation at ten years old, which planted at seven different sites in Java. The carbon (C) analysis was done with Walkley and Black and N with Kjeldahl method. Meanwhile for total P, K, Ca, Mg, Na, Fe, Mn, and Cu, the samples were extracted with mixture between HClO4 and HNO3, extracted P was measured with spectrophotometer and the metals of K, Ca, Mg, Na, Fe, Mn, and Cu were measured with Atomic Absorption Spectroscopy (AAS). The result showed that carbon content was not much different, valued 46.49-52.32%, and N and P had a little bit different value 0.52-1.28% and 0.04-0.14%, respectively. K, Ca, and Mg content was slightly different valued 0.06-0.52%, 1.69-2.64%, and 0.10-0.45%, respectively, while Na almost had not different ranged between 0.018-0.025%. Fe and Mn content were much different among the sites ranged 185-898 ppm and 63-202 ppm, respectively, while Cu and Zn were not much different valued 54-126 ppm and 32-58 ppm, respectively. The relationship between levels of elements that are mobile (C, N, and P) on litter and soil do not indicate a real trend. Otherwise immobile elements (K, Ca, Mg, and Na) are always consistent between the levels of nutrients in the litter with high levels of nutrients in the soil.