Kajian pola pembasahan pada tanah pasiran sebagai dasar penentuan jarak optimum penetes

NGADISIH, Prof. Dr. Ir. Muhjidin Mawardi

2008 | Tesis | S2 Teknik Pertanian

Tujuan penelitian ini adalah mendeskripsikan pola sebaran air dalam tanah pasiran (pola pembasahan) pada berbagai variasi bahan organik dan debit tetesan kaitannya dengan jarak optimum penetes/emitter. Pola pembasahan diamati secara eksperimental di dalam laboratorium dengan bak kaca berukuran panjang 100 cm lebar 100 cm serta tebal 20 cm yang dilengkapi dengan sensor pembaca kadar lengas tanah (blok gipsum). Adapun data yang diperoleh dari hasil penelitian dianalisis secara deskriptif kuantitatif berdasarkan factor-faktor yang mempengaruhi pola pembasahan tanah. Sedangkan jarak optimum emitter ditentukan dengan menganalisa pola pembasahan pada berbagai skenario penempatan emitter sehingga diperoleh zona kering, zona overlapping dan zona perkolasi sekecil mungkin. Hasil penelitian menunjukkan bahwa pola pembasahan tanah pasiran dipengaruhi oleh jumlah penambahan bahan organic dalam tanah serta debit tetesan. Hal tersebut selanjutnya berdampak pada jarak optimum antar penetes tiap tanaman. Adapun jarak optimum emitter per tanaman Cabai (Capsium annum sp) pada tanah tanpa penambahan bahan organic adalah 5 cm untuk debit tetesan 9 ml/menit, 10 cm untuk debit 5 ml/menit, dan 10 cm untuk debit tetesan 3 ml/menit. Jarak optimum emiter pada tanah yang diberi bahan organik dengan takaran 1 : 1 adalah 10 cm untuk debit tetesan 9 ml/menit, 10 cm untuk debit 5 ml/menit, dan 10 cm untuk debit tetesan 3 ml/menit. Sedangkan jarak optimum emiter pada tanah pasiran yang diberi bahan organik dengan takaran 1 : 2 adalah 10 cm untuk debit tetesan 9 ml/menit, 10 cm untuk debit 5 ml/menit dan 10 cm untuk debit tetesan 3 ml/menit.

The aim of this research is to describe distribution pattern of the water in the soil concerning with the optimum distance of the emitter. Wetting pattern was examined experimentally in the laboratory using glass box which has length of 100 centimeters, width of 100 cm and thickness of 20 centimeters completed with sensor of soil moisture. The data obtained from the research were analyzed throught descriptive quantitative analysis based on the factors that influencing soil wetting pattern. Meanwhile, the optimum distance of the emitter was determined by analyzing wetting pattern in the various scenario of the emitter’s allocation due to gain the dry zone, overlapping zone and percolation zone as minimum as possible. The result of the research shows that movement and distance of the wetting which direct lateral is wider as much as the adding of organic material in the soil. However, movement and the distance of wetting which is down vertically is not always more shallow by means of increasing of orgnic material. The movement and the distance of wetting which is down vertically is much deeper, and, which directs to lateral becomes wider by the increasing of the emitter’s debit. However, it does not occur for soil which is added with organic material. The optimum distannce of the emitter for control threatment with debit 9 ml/minute is 5 centimeters; debit 5 ml/minute is 10 centimeters; debit 3 ml/minute is 10 centimeters. The optimum distance of the emitter on the soil whic is put organic material with comparison 1 : 1, for debit 9 ml/minute is 10 centimeters, 5 ml/minute is 10 centimeters; and 3 ml/minute is 10 centimeters. The optimum distance of the emitter on sandy soil which is added organic material with comparison 1 : 2, for debit 9 ml/minute is 10 centimeters; 5 ml/minute is 10 centimeters; and 3 ml/minute is 10 centimeters.

Kata Kunci : wwetting pattern,sandy soil,debit,organic material,the optimum distance of the emitter, wetting pattern, sandy soil, debit, organic material, the optimum distance of the emitter