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Abstract

Abstract

Dry land farmers in Jatinangor only able to plant during the growing season twice a year. Runoff harvesting systems for agriculture is expected to answer the problems of water availability in drylands. This study aimed to explore the period of water deficit in the soil, which is used as the basis for determining the scheduling and amount of irrigation water needed for the planting pattern recommended in runoff harvesting systems for dryland agriculture. The method used in this research is descriptive method, by analyzing the water balance of dry land in order to determine the frequency of irrigation and irrigation needs. Parameters required in the analysis of soil water balance are: precipitation, evapotranspiration, soil water availability on the condition of field capacity and permanent wilting point based on the value of MAD (Maximum Allowable depletion) are permitted. The results showed a total water deficit of 217.42 mm in the cropping pattern of sweet corn - sweet corn - sweet potato, where the period of water deficit occurs during planting sweet potato in the third decade of May to the first decade of September.Irrigation scheduling is determined by the selection of fixed interval irrigation between interval 2 days, 4 days and 5 days. With an area of fields to be watered amounted to 264 meter square (57.4 metercubic water needs), 60 meter cubic of runoff that was collected in the storage pond capable to irrigate the entire of land planted with sweet potato, it indicates that the runoff water harvesting systems can increase cropping intensity dry land farming.

Abstrak

Petani lahan kering di Kecamatan Jatinangor hanya mampu menanam dua kali dalam setahun. Sistem pemanenan air limpasan permukaan untuk pertanian diharapkan mampu menjawab permasalahan ketersediaan air di lahan kering. Penelitian ini bertujuan untuk mencari periode defisit air di lahan penelitian yang digunakan sebagai dasar dalam menentukan penjadwalan dan kebutuhan air irigasi pada pola tanam yang direkomendasikan pada sistem pemanenan air limpasan untuk pertanian lahan kering. Metode yang digunakan dalam penelitian ini adalah metode deskriptif, yaitu dengan menganalisis neraca air lahan kering guna menentukan frekuensi irigasi dan kebutuhan air irigasi. Parameter yang dibutuhkan dalam analisis neraca air lahan terdiri dari curah hujan, evapotranspirasi, ketersediaan air tanah pada kondisi kapasitas lapang dan titik layu permanen berdasarkan nilai MAD (Maximum Allowable Depletion) yang diijinkan. Hasil penelitian menunjukkan total defisit air sebesar 217,42 mm pada pola tanam jagung manis – jagung manis – ubi cilembu, dimana periode defisit air terjadi pada saat penanaman ubi cilembu pada dasarian ketiga Mei hingga dasarian pertama September. Penjadwalan irigasi ditentukan secara fix interval dengan pilihan interval irigasi antara 2 hari sekali, 4 hari sekali dan 5 hari sekali. Dengan luas bidang yang harus diairi adalah sebesar 264 m2 (kebutuhan air 57,4 m3) maka kolam tampungan sebesar 60 m3 mampu mengairi seluruh lahan yang ditanami ubi cilembu, hal ini menunjukkan bahwa sistem pemanenan air limpasan dapat meningkatkan intensitas tanam pertanian lahan kering

Keywords

runoff harvesting irrigation water balance scheduling irrigation dry land farming

Article Details

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