Oil Palm Bulletin No. 49 (November 2004) p7-14

Performance of the poritex geotextile hose in oil palm irrigation

ABDUL RAZAK Jelani * , AHMAD Hitam * , ZULKIFLI Tumpang ** , MOHD SOLAH Deraman * , JOHARI Jamak

Drip irrigation is one of the most popular systems that offer several advantages over other irrigation systems. Ample water is slowly applied to the root zone to fully satisfy the crop needs. It is the continuous slow emission of water along a delivery line.

A Spanish made irrigation tape called the poritex geotextile hose was tested for oil palm irrigation. Made of geotextile, it allows the water to seep through its wall along its length without having to use emitters as in other drip irrigation systems.
The trial was carried out at FELCRA Inas, Kuala Johol, Negeri Sembilan on flat land of 1 ha area. It has two dry seasons with monthly rainfall of 150 mm (below evapotranspiration in January-February and June-August). The soil was clayey (ex-paddy field) and planted with 13-year-old oil palm The parameters observed were the ability of the hose to deliver water according to its specifications and its durability over time.
Two parallel poritex lines of 5 m length were buried about 15 cm to 30 cm deep. They were placed 3 m from the palm trunk, running towards the stacking rows. A pumpset of 5400 litres hr -1 at 18 m total dynamic head (TDH) was used to run the system. The irrigation time was 11 hr a day.
It was observed that the hose could deliver water at 1.2 litres hr-1 m-1 at an operating pressure of 0.24 bar as specified. A problem was that it was prone to termite attack causing leaks. It is, therefore, recommended that the hose be only used in areas without termites. Over the four years of the trial, it was concluded the poritex geotextile hose was capable of irrigating oil palm with some precautions as mentioned earlier. It was estimated that the extra FFB yield that has to be generated to justify the system is 6 t ha-1 yr-1 to 25 t ha-1 yr-1based on FFB prices of RM 400 t-1 to RM 100 t-1 , respectively.
Abstrak: Sistem pengairan titis merupakan satu sistem yang paling popular yang menawarkan pelbagai kelebihan berbanding sistem pengairan lain. Ini kerana air dibekalkan secara perlahan ke dalam kawasan akar untuk memberi jumlah air yang mencukupi bagi keperluan pokok. Ini merupakan pembekalan air secara sekata dan perlahan di sepanjang saluran pembekalan air.
Satu produk keluaran Sepanyol dikenali sebagai poritex geotextile hose telah digunakan dalam percubaan ini. Produk ini diperbuat dari bahan geotekstil, membenarkan air untuk meresap di sepanjang dindingnya tanpa menggunakan emitter seperti dalam sistem pengairan titis biasa.
Percubaan telah dijalankan di FELCRA Inas, Kuala Johol di Negeri Sembilan di sebuah ladang yang rata seluas 1 ha. Kawasan ini mengalami dua musim kering kurang dari 150 mm (di bawah keperluan sejat-transpirasi pada bulan Januari-Februari dan Jun-Ogos) setiap tahun. Tanahnya adalah dari jenis liat (bekas tanaman padi) dan telah pun ditanam dengan sawit berumur 13 tahun.
Dalam ujian ini, dua hos sepanjang 5 m dipasang secara selari dan ditanam sedalam 15 cm-30 cm. Hos ini ditanam sejauh 3 m dari pangkal pokok dan ditanam mengarah ke lorong pengumpulan pelepah. Sebuah pam berkapasiti 5400 liter jam-1dan turus tekanan 18 m digunakan untuk menjalankan sistem. Masa pengairan telah ditetapkan 11 jam sehari.
Hos ini didapati berupaya membekalkan air pada kadar 1.2 liter jam-1pada tekanan operasi 0.24 bar sebagaimana spesifikasi yang diberikan. Satu masalah diperhatikan di mana hos ini terdedah kepada serangan anai-anai yang menggigit hos dan menyebabkannya bocor. Oleh itu, hos ini hanya sesuai digunakan di kawasan yang tiada populasi anai-anai. Dalam tempoh empat tahun percubaan, sistem pengairan dalam tanah menggunakan hos poritex geotekstil disimpulkan boleh digunakan bagi mengairi sawit tertakluk kepada langkah berjaga-jaga sepertimana dinyatakan. Adalah dianggarkan bahawa lebihan buah tandan segar yang perlu dijanakan bagi keluasan 1 ha adalah 6 t thn-1– 25 t thn-1berdasarka harga buah tandan segar RM 400 t-1– RM 100 t-1masing-masing.

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