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Abstract

Abstract
Increasing cultivation area in a watershed has implications on increase of runoff and erosion rate. Agroforestry system can reduce erosion rate through management of agricultural crops under the stand of annual plant of white teak (Gmelina arborea sp.). This study aims to assess the runoff and erosion rate
in watershed area in some types of agroforestry cropping systems. In Cianten-Cipancar watershed area there are several crops cultivated i.e. maize, turmeric, red bean and local chili. In order to assess the runoff and erosion rate in watershed area is designed 3 experimental plots involving 4 types of horticultural crops. Plot 1 uses intercropping turmeric, maize, red bean, local chili. Plot 2 uses intercropping turmeric, corn, red beans. Plot 3 uses pattern of monoculture planting of local chili. The average rainfall of 21.6 mm is resulted in runoff 0.28 mm (Plot 1), 0.55 mm (Plot 2) and 0.94 mm (Plot 3). Intensity of rainfall on each plot (63.4 mm/h, 51.6 mm/h, 63.4 mm/h) resulted in runoff and erosion 0.83 mm, 29.67 kg/ha, 1.59 mm, 275.01 kg/ha, 5.0 mm, 464.78 kg/ha, respectively. Average erosion occurring was 9.27 kg/ha (Plot 1), 55.65 kg/ha (Plot 2) and 101.23 kg/ha (Plot 3). The rain events in the study was 30 times with a total rainfall of 647.11 mm. The smallest rainfall of 0.2 mm resulted in runoff on Plot 3 of 0.01 mm and erosion of 1.13 kg/ha but in Plot 1 and Plot 2 there was no runoff and erosion.

Abstrak
Peningkatan kawasan budidaya pada suatu Daerah Aliran Sungai (DAS) berimplikasi pada peningkatan laju limpasan dan erosi. Sistem agroforestry dapat menurunkan tingkat erosi melalui pengelolaan tanaman pertanian di bawah tegakan tanaman tahunan Jati putih (Gmelina arborea sp.). Penelitian ini bertujuan untuk mengkaji tingkat laju limpasan permukaan dan erosi yang terjadi di DAS pada beberapa jenis sistem tanam agroforestry. Di kawasan DAS Cianten-Cipancar terdapat beberapa tanaman yang dibudidaya petani yaitu jagung, kunyit, kacang merah dan cabe rawit lokal. Guna mengkaji tingkat laju limpasan permukaan dan erosi pada kawasan DAS tersebut maka didesain 3 plot percobaan yang melibatkan 4 jenis tanaman hortikultura. Plot 1 menggunakan pola tanam tumpangsari (kunyit, jagung, kacang merah, cabe rawit lokal). Plot 2 menggunakan pola tanam tumpangsari (kunyit, jagung, kacang merah). Plot 3 menggunakan pola tanam monokultur cabe rawit lokal. Hasil penelitian menunjukkan bahwa limpasan rata-rata pada masing-masing plot (1-3) adalah 0.28 mm, 0.55 mm, 0.94 mm pada tingkat curah hujan rata-rata 21.6 mm. Intensitas hujan pada masing-masing plot (63.4 mm/jam, 51.6 mm/jam, 63.4 mm/jam) menyebabkan terjadinya limpasan dan erosi masing-masing sebesar 0.83 mm, 29.67 kg/ha, 1.59 mm, 275.01 kg/ha, 5.0 mm, 464.78 kg/ha. Erosi rata-rata yang terjadi adalah 9.27 kg/ha (Plot 1), 55.65 kg/ha (Plot 2) dan 101.23 kg/ha (Plot 3). Jumlah kejadian hujan selama penelitian adalah 30 kali dengan total curah hujan 647.11 mm. Curah hujan terkecil sebesar 0.2 mm mengakibatkan limpasan pada Plot 3 sebesar 0.01 mm dan erosi
1.13 kg/ha namun pada Plot 1 dan Plot 2 tidak terjadi limpasan dan erosi.

Keywords

Agroforestry system runoff erosion intercropping monoculture

Article Details

Author Biography

Devianti Devianti, Universitas Syiah Kuala

Program Studi Teknik Pertanian, Fakultas Pertanian

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