Sonora, Windy Ellprimus and Dr. Eng. Donny Harisuseno, ST., MT. and Jadfan Sidqi Fidar, ST. MT. (2021) Prediksi Laju Infiltrasi Berdasarkan Porositas Tanah dan Komposisi Tanah di DAS Lesti Kabupaten Malang. Sarjana thesis, Universitas Brawijaya.
Abstract
Infiltrasi merupakan proses masuknya air ke dalam tanah dan banyaknya air yang masuk ke dalam tanah per satuan waktu disebut dengan laju infiltrasi. Laju infiltrasi berperan penting dalam mengoptimalkan ketersediaan air bagi pertumbuhan tanaman serta meminimalisir limpasan permukaan dan erosi. Ada banyak faktor yang mempengaruhi laju infiltrasi, dan salah satu yang paling berpengaruh adalah sifat fisik tanah yaitu tekstur tanah dan porositas tanah. Dalam menentukan laju infiltrasi, diperlukan pengukuran laju infiltrasi dilapangan. Pengukuran di lapangan membutuhkan banyak waktu, biaya dan tenaga, sehingga diperlukan prediksi laju infiltrasi berdasarkan faktor yang mempengaruhinya agar penentuan laju infiltrasi menjadi lebih mudah dan efisien. Dengan demikian, penjelasan ini dijadikan sebagai dasar untuk memprediksi laju infiltrasi berdasarkan porositas tanah dan komposisi tanah di DAS Lesti Kabupaten Malang. Dalam penelitian ini, pengukuran laju infiltrasi di lapangan menggunakan alat Double Ring Infiltrometer dan sampel tanah dianalisa di laboratorium. Komposisi tanah diperoleh dari analisa distribusi ukuran butir tanah dan porositas tanah dihitung berdasarkan persamaan hubungan antara bulk density dengan berat jenis tanah. Selanjutnya, analisa regresi linier berganda digunakan untuk memprediksi laju infiltrasi dimana laju infiltrasi lapangan dijadikan sebagai variabel dependent dan porositas tanah dan komposisi tanah dijadikan sebagai variabel independent. Terdapat tiga alternatif variabel yang diajukan sebagai model prediksi dan alternatif variabel terbaik akan dipilih berdasarkan nilai koefisien determinasi tertinggi. Kemudian untuk melihat tingkat akurasi hasil model prediksi dilakukan analisa perbandingan antara laju infiltrasi hasil prediksi dengan laju infiltrasi pengukuran di lapangan Penelitian ini telah menghasilkan : (1) Nilai laju infiltrasi lapangan yang diukur menggunakan alat Double Ring Infiltrometer memiliki nilai laju infiltrasi konstan yang berkisar diantara 0,100 mm/menit hingga 3,000 mm/menit dengan nilai laju infiltrasi rata- rata sebesar 1,883 mm/menit. (2) Prediksi laju infiltrasi menghasilkan model persamaan regresi dari alternatif variabel terbaik yaitu berdasarkan porositas tanah dan komposisi tanah lanau dengan porositas tanah memiliki nilai berkisar diantara 33,691% hingga 75,671% dan komposisi tanah lanau berkisar diantara 18,665% hingga 61,936%. Adapun hasil model prediksi yang diperoleh yaitu IRp = 1,893 + 0,032(PO%) - 0,049(SI%) dimana PO adalah Porositas Tanah dan SI adalah Komposisi Tanah Lanau sehingga diperoleh nilai laju infiltrasi hasil prediksi berkisar diantara diantara 0,093 mm/menit hingga 3,177 mm/menit dengan nilai laju infiltrasi rata-rata sebesar 1,831 mm/menit.(3) Berdasarkan analisa perbandingan antara nilai laju infiltrasi lapangan dengan nilai laju infiltrasi prediksi diperoleh nilai koefisien determinasi sebesar sebesar 0,989 yang berarti akurasi nilai laju infiltrasi prediksi sangat baik. Lalu diperoleh nilai uji NSE sebesar 0,724 yang berarti model prediksi tergolong memenuhi. Nilai RMSE yang diperoleh sebesar 0,495 dan uji Bland Altman plot menunjukkan nilai perbedaan antara laju infiltrasi lapangan dengan laju infiltrasi prediksi berada dalam batas kesesuaian 95% interval kepercayaan dan dengan perbedaan rerata yang sangat rendah (bias) yaitu sebesar 0,209, yang berarti secara statistik tidak terdapat perbedaan yang bermakna antara nilai laju infiltrasi lapangan dengan nilai laju infiltrasi prediksi. Sehingga model prediksi yang dibangun oleh porositas tanah dan komposisi tanah lanau dapat dikatakan layak dijadikan sebagai model prediksi laju infiltrasi.
English Abstract
Infiltration is the process of water entry into the soil and the amount of water entering into the soil per unit of time is called infiltration rate. Infiltration rate is an important role in optimizing the availability of water for plants and also minimizing runoff and erosion. There are so many factors that affect the infiltration rate, and the most crucial one is the physical properties of the soil, such as soil texture and soil porosity. To determine the infiltration rate is necessary to measure the infiltration rate in the field. Measuring infiltration rate requires more time, cost money, and energy so it’s necessary to predict infiltration rate based on the factor that affects it. So in that determination, it would be easy and efficient. Therefore, this explanation is used as the basis for the prediction of infiltration rate based on soil porosity and soil content in Lesti watershed Kabupaten Malang. In this study, the measuring infiltration rate in the field is used Double Ring Infiltrometer and the soil sample was collected and analyzed in Laboratory to determine soil porosity and soil content. Soil content is obtained from the analysis of the soil particle size distribution and soil porosity is calculated from the equation of the relationship between bulk density and particle density of the soil. Furthermore, the analysis of multiple linear regression is used to predict the infiltration rate in which the field measured infiltration rate as a dependent variable and soil porosity and soil content as the independent variable. There are three alternative variables proposed as model prediction and the best alternative variable would be selected based on the highest value of the coefficient determination. Afterward, to see the accuracy of the prediction model results, the comparison analysis was carried out between the predicted infiltration rate and the field measured infiltration rate. The result of this study are as follow : (1) The value of the field measured infiltration rate use Double Ring Infiltrometer have the steady infiltration rate that ranged from 0,100 mm/minute to 3,000 mm/minute and the average of the infiltration rate is 1,883 mm/minute. (2) The prediction of infiltration rate give the regression equation model that is coming from the best alternative variables, namely based on the soil porosity and the silt content. Which the value of soil porosity ranged from 33,691% to 75,671% and the silt content ranged from 18,665% to 61,936%. The results of the prediction model are obtained IRp = 1,941 + 0,032(PO%) - 0,051(SI%) where PO is Soil Porosity and SI is Silt Content so that the value of the predicted infiltration rate ranged from 0,093 mm/minute to 3,177 mm/minute with the average of the infiltration rate was 1,831 mm/minute. (3) The comparison analysis betweenthe field measured infiltration rate and the predicted infiltration rate has obtained the value of coefficient determination was 0,989, which means the accuracy of the predicted infiltration rate to the field measured infiltration rate is great, the NSE value was 0,724 that its indicated qualify, the RMSE value was 0,495 which means the error level was low. The Bland Altman Plot test showed the difference value between the field measured infiltration rate and the predicted infiltration rate was within the 95% confidence interval with the low mean difference (bias) was 0,209, which means the difference between the field measured infiltration rate and predicted infiltration rate was not statistically significant. Therefore, the prediction model built by soil porosity and silt content can be suitable as a prediction model for infiltration rate
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| Item Type: | Thesis (Sarjana) |
|---|---|
| Identification Number: | 0521070108 |
| Uncontrolled Keywords: | Kata Kunci: Laju Infiltrasi, Prediksi, Porositas Tanah, Komposisi Tanah |
| Subjects: | 600 Technology (Applied sciences) > 627 Hydraulic engineering > 627.5 Reclamations, Irrigation, related topics > 627.52 Irrigation |
| Divisions: | Fakultas Teknik > Teknik Pengairan |
| Depositing User: | yulia Chasanah |
| Date Deposited: | 23 Dec 2021 02:09 |
| Last Modified: | 01 Oct 2024 08:50 |
| URI: | http://repository.ub.ac.id/id/eprint/187607 |
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