Analisis Kapasitas Infiltrasi Tanah pada Berbagai Penggunaan Lahan

Abstract

Kebutuhan sumberdaya lahan yang terus meningkat berdampak pada perubahan penggunaan lahan. Perubahan lahan hutan menjadi lahan garapan menyebabkan menurunnya kualitas tanah yang selanjutnya berdampak pada menurunnya kemampuan tanah meresapkan air (infiltrasi). Infiltrasi tanah merupakan salah satu faktor penting yang menentukan kondisi hidrologi suatu wilayah (DAS), sehingga perlu mendapat perhatian terutama di wilayah perkebunan sawit yang seringkali dianggap sebagai penggunaan lahan yang dapat menurunkan kualitas kondisi hidrologi wilayah. Penelitian mengenai infiltrasi dan keterkaitannya dengan sifat-sifat tanah telah dilakukan di perkebunan kelapa sawit, tegalan, dan kebun campuran. Hasil penelitian menunjukkan bahwa kapasitas infiltrasi berbeda untuk jenis penggunaan lahan yang berbeda. Kapasitas infiltrasi pada kebun kelapa sawit tergolong kelas cepat-agak cepat, kecuali pada areal gawangan hidup yang tergolong sedang. Areal gawangan mati di lahan kelapa sawit memiliki kapasitas infiltrasi tertinggi, diikuti areal tegalan, piringan di lahan kelapa sawit, non gawangan di lahan kelapa sawit, kebun campuran, dan gawangan hidup di lahan kelapa sawit. Areal gawangan mati memiliki kandungan bahan organik, pori drainase, dan permeabilitas yang lebih tinggi daripada penggunaan lahan lainnya. Hasil analisis korelasi menunjukkan bahwa kapasitas infiltrasi berkorelasi sangat kuat dan positif dengan bahan organik, pori drainase dan permeabilitas, serta berkorelasi kuat dan negatif dengan bobot isi tanah.

Land resource needs increasing impact on changes of land use. The change of forest land into arable land causes a decrease in soil quality, resulting in a reduction of the ability of the soil to absorb water (infiltration). Soil infiltration is a crucial factor to describe the hydrology cycle. Thus, it is necessary to study infiltration and its relationship to other soil properties. Soil Infiltration is an important factor determining the hydrological condition of the area (watershed). So, it needs attention, especially in oil palm plantation areas which are often considered as land uses that can reduce the hydrological conditions of the area. Research on infiltration and its relationship to soil properties has been carried out in oil palm plantation, dry fields, and mixed gardens. The results showed that the infiltration capacities are different for different land uses. The infiltration capacity in palm oil plantations is classed as fast - rather fast, except in the harvesting path, which is relatively moderate. The frond stack area in palm oil has the highest infiltration capacity, followed by the dry annual crop field, piringan in palm oil (circle around oil palm trunk), interrow zones in palm oil, mixed garden and harvesting path in palm oil. The frond stack area has higher organic matter content, drainage pores, and permeability than other land uses. The results of correlation analysis showed that infiltration capacity was strongly and positively correlated with organic matter, drainage pores and permeability, and strongly and negatively correlated with soil bulk density.