Pemanfaatan Indeks Vegetasi Dan Sistem Informasi Geografis (Sig) Untuk Pemetaan Kandungan Bahan Organik Tanah Di Kecamatan Turen, Kabupaten Malang

Sudharta, Khanza Amaladewi (2019) Pemanfaatan Indeks Vegetasi Dan Sistem Informasi Geografis (Sig) Untuk Pemetaan Kandungan Bahan Organik Tanah Di Kecamatan Turen, Kabupaten Malang. Sarjana thesis, Universitas Brawijaya.

Abstract

Luas lahan pertanian di Kecamatan Turen hampir setengah dari total luasan kecamatan yang ditanami komoditas tanaman pangan, khususnya tanaman padi dan jagung. Selama kurun waktu 4 tahun, produktivitas tanaman pangan di Kecamatan Turen mengalami penurunan, yang diduga karena adanya perbedaan status kesuburan tanah dan perbedaan praktek budidaya. Kesuburan tanah dapat diketahui dari kandungan bahan organik tanah. Umumnya, petani di Kecamatan Turen tidak mengetahui kandungan bahan organik tanah sebelum mengolah tanah dan menggunakan pupuk kimia buatan untuk meningkatan produktivitas tanah. Oleh karena itu, agar petani dapat mengetahui status kesuburan tanah maka diperlukan pendekatan secara spasial untuk mengetahui sebaran bahan organik tanah. Penelitian ini bertujuan untuk mengetahui pengaruh perbedaan penggunaan lahan dan nilai NDVI terhadap kandungan bahan organik tanah, menganalisis nilai indeks vegetasi dalam penentuan kandungan serta pola sebaran bahan organik tanah dan pengaruh kandungan bahan organik tanah terhadap produktivitas tanaman. Penelitian ini dilaksanakan pada bulan April – Juli 2019 di Kecamatan Turen, Kabupaten Malang. Penelitian ini menggunakan metode survei pada 21 Satuan Peta Lahan (SPL). Satuan Peta Lahan (SPL) dibedakan berdasarkan: bentuk lahan (landform), lereng, relief, penggunaan lahan (sawah irigasi dan sawah tadah hujan) dan kelas indeks vegetasi (rendah, sedang, tinggi). Setiap perbedaan satuan lahan ditentukan titik pengamatan dan diulang sebanyak 3 kali. Contoh tanah diambil di setiap titik pengamatan pada kedalaman 0-20 cm. Analisis kandungan bahan organik tanah dilakukan di Laboratorium Kimia Tanah, menggunakan metode Walkley & Black. Interpolasi data menggunakan Inverse Distance Weighted (IDW) digunakan untuk pemetaan bahan organik tanah. Analisis statistik dilakukan menggunakan software Genstat Discovery Edition 18 th, yang terdiri dari tiga tahapan: (a) uji korelasi untuk mengetahui hubungan nilai NDVI terhadap kandungan bahan organik tanah serta kandungan bahan organik tanah terhadap produktivitas tanaman; (b) uji regresi untuk mengetahui pengaruh nilai NDVI terhadap kandungan bahan organik tanah serta kandungan bahan organik tanah terhadap produktivitas tanaman; (c) uji akurasi antara nilai kandungan bahan organik tanah lapangan terhadap nilai estimasi kandungan bahan organik tanah dengan menggunakan uji persamaan regresi, uji perbandingan dan uji-t berpasangan. Hasil penelitian menunjukkan terdapat perbedaan kandungan bahan organik tanah pada penggunaan lahan sawah irigasi dengan sawah tadah hujan. Kandungan bahan organik tanah pada sawah irigasi dengan kelas NDVI rendah, sedang dan tinggi berturut-turut sebesar 1,6%, 4,4% dan 4,2%, sedangkan pada sawah tadah hujan berturut-turut sebesar 1,6%, 2,8% dan 3,9%. Perbedaan manajemen yang ditemukan pada lokasi penelitian berupa pengolahan tanah, pembakaran jerami dan rotasi tanaman. Sebaran kandungan bahan organik tanah digolongkan dalam 5 kelasii sangat rendah (264 ha), rendah (542 ha), sedang (162 ha), tinggi (250 ha) dan sangat tinggi (94 ha). Terdapat hubungan yang kuat antara nilai NDVI dengan kandungan bahan organik tanah (r = 0,9387) dan nilai NDVI memberikan pengaruh sebesar R2 = 0,7808 dengan persamaan regresi y= 8,5048x + 0,0237. Berdasarkan hasil pendugaan kandungan bahan organik tanah menggunakan persamaan regresi diperoleh lima kelas sebaran bahan organik tanah, yaitu kelas sangat rendah (26,31 ha), rendah (229,82 ha), sedang (341,51 ha), tinggi (529 ha) dan sangat tinggi ( 257,28 ha). Hasil uji akurasi pertama dengan menggunakan persamaan regresi didapatkan nilai sebesar 68,21%, uji akurasi kedua dengan uji perbandingan nilai bahan organik lapangan dengan estimasi bahan organik tanah didapatkan nilai sebesar 62,2% dan uji akurasi ketiga yaitu uji-t berpasang menunjukkan tidak ada perbedaan antara bahan organik lapangan dengan estimasi bahan organik tanah. Selain itu, terdapat hubungan yang kuat juga ditunjukkan oleh kandungan bahan organik tanah terhadap produktivitas tanaman (r = 0,8322) dan bahan organik tanah memberikan pengaruh sebesar R2 = 0,6926 dengan persamaan y = 0,0608 + 2,963. Hasil tersebut menunjukkan bahwa kenaikan bahan organik tanah akan diikuti oleh peningkatan produktivitas tanaman.

English Abstract

The area of agricultural land in Turen sub-district is almost half of the total area of the sub-district planted with food crop commodities, especially rice and corn. For the past 4 years, the productivity of food crops in the district Turen decreased, presumably due to differences in soil fertility status and differences in cultivation practices. Soil fertility can be known from the soil organic matter contenct. Generally, farmers in Turen Subdistrict did not know the soil organic matter content before tilling the soil and using artificial chemical fertilizers to increase soil productivity. Therefore, in order for farmers to know the status of soil fertility, a spatial approach is needed to determine the distributin of soil organic matter. This study aims to determine the effect of land management on soil organic matter content, analyze the value of vegetation index in determining the content and distribution patterns of soil organic matter and the effect of soil organic matter content on plant productivity. This research was conducted in April – July 2019 in Turen District, Malang Regency. This research used a survey method, covering 15 Land Mapping Units (LMU). The land mapping units (LMU) are distinguished by: landform, slope, relief, landuse (irrigated rice field and non irrigated rice field) and vegetation index class (low, medium, high). Each difference in land units is determined by observation point and it is repeated in 3 times. Soil samples were taken at each observation point in the depth of 0 – 20 cm. Analysis of soil organic matter content was carried out at the Soil Chemical Laboratory, using the Walkley & Black method. Data interpolation using Inverse Distance Weighted (IDW) was used for mapping soil organic matter. Statistical analysis was performed using software Genstat Discovery Edition 18th, which consisted of three stages (a) correlation test to determine the relationship between NDVI values with soil organic matter and soil organic matter with productivity (b) regression test to determine the effect of NDVI values on soil organic matter and soil organic matter on productivity (c) accuracy test between the value of field organic matter against estimates value of soil organic matter using the regression equation test, comparison test and paired sample t test. The results showed there were differences in the content of soil organic matter in irrigated rice field and non irrigated rice field. The soil organic matter in irrigated rice field with low, medium and high of NDVI classes respectively were 1.6%, 4.4% and 4.2%, while in non irrigated rice fields 1.6%, 2.8% and 3.9%. The differences of management found in location were intensive soil cultivation, straw burning and crop rotation. The distribution of soil organic matter is classified into five classes, very low (264 ha), low (542 ha), moderate (162 ha), high (250 ha) and very high (94 ha). There is a strong relationship between NDVI classes and soil organic matter (r = 0.9387) and the NDVI’s class gives an effect on soil organic matter (R2 = 0.7808) with a regression eqution y = 8.5048x + 0.0237. Based on theiv estimation of soil organic matter using a regression equation obtained five classes of soil organic matter distribution, in very low (26.31 ha), low (229.82 ha), moderate (341.51 ha), high (529 ha) and very high (572.28 ha). The first accuracy tes results using the regression equation obtained a value of 68.21%, the second accuracy test with a comparison test between field’s soil organic matter with estimation of soil organic matter obtained a value of 62.2% and the third accuracy test using paired sample t test showed no difference between field’s soil organic matter with estimation of soil organic matter. In addition, the correlation was also shown by the relationship between soil organic matter with produtivity (r = 0.8322) and the soil organic matter gives an effect on productivity (R2 = 0.6926) with a regression eqution y = 0.0608 + 2.963. These results indicate that an increase of soil organic matter will be followed by an increase of crop productivity.

Other obstract

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Item Type: Thesis (Sarjana)
Identification Number: SKR/FP/2019/870/052000954
Subjects: 600 Technology (Applied sciences) > 631 Specific techniques; apparatus, equipment materials > 631.4 Soil science > 631.47 Soil and land-use surveys
Divisions: Fakultas Pertanian > Ilmu Tanah
Depositing User: Nur Cholis
Date Deposited: 02 Oct 2020 02:46
Last Modified: 25 Oct 2021 07:26
URI: http://repository.ub.ac.id/id/eprint/179465
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