Pembuatan dan Analisa Peta Persebaran pH Kebun Pendidikan Cikabayan, Dramaga, Institut Pertanian Bogor

Abstract

Pengelolaan lahan pertanian dan perkebunan yang berkelanjutan memerlukan informasi spasial karakteristik tanah yang andal, salah satunya adalah sebaran spasial pH tanah. Sebaran spasial pH tanah saat ini didekati menggunakan berbagai teknik interpolasi geostatistik. Namun, berbagai teknik interpolasi tersebut memiliki sumber kesalahan tersendiri yang biasanya bersifat spesifik lokasi sebagai akibat dari keragaman sifat kimia dan fisik tanah. Penelitian ini bertujuan mempelajari sebaran pH tanah di lokasi penelitian dan melakukan pengujian akurasi pada enam teknik interpolasi, yaitu IDW, kriging, local polynomial, spline, radial basis, dan topo to raster menggunakan 950 data pH tanah, untuk mengetahui teknik intepolasi mana yang menghasilkan data sebaran pH tanah yang akurat dan dapat diandalkan. Selain itu, dikaji pula hubungan antara sebaran pH dengan kelerengan di area kebun pendidikan IPB, di Cikabayan, Dramaga. Uji akurasi dilaksanakan melalui perhitungan RMSE (Root Mean Square Error) dengan mengggunakan 50 titik uji. Pola sebaran kemasaman (pH) tanah pada area penelitian dari hasil 6 teknik interpolasi memiliki kemiripan satu dengan yang lain. Rentang pH terbesar didapatkan pada hasil interpolasi spline, sedangkan kriging menunjukkan rentang pH terkecil. Uji akurasi RMSE pada enam metode interpolasi sebaran pH tanah tersebut menghasilkan urutan radial basis < spline < IDW < local polynomia l< kriging < topo to raster. pH tanah di daerah penelitian cenderung meningkat seiring dengan penurunan persentase kelerengan. kata kunci: geostatistik, interpolasi, kelerengan, pH tanah, uji akurasi.

Sustainable agricultural and plantation land management requires reliable spatial information on soil characteristics, which is the soil pH. The current spatial distribution of soil pH is approximated using various geostatistical interpolation techniques. However, these various interpolation techniques have their own sources of error which are usually site specific as a result of the diversity of soil chemical and physical properties. This study aims to observe the distribution of soil pH at the research site and perform accuracy testing on six interpolation techniques including IDW, kriging, local polynomial, spline, radial base, and topo to raster using 950 soil pH data, to check for the most accurate technique which results reliable soil pH distribution data. In addition, the relationship between the pH distribution and the slope in the Cikabayan educational farm area of IPB in Dramaga Bogor was also studied. The accuracy test is carried out by calculating the RMSE (Root Mean Square Error) using 50 test points. The patterns of soil acidity (pH) in the study area resulted from the six interpolation techniques are similar to each others. The largest pH range was obtained from the spline interpolation, while the kriging has resulted ini the smallest pH range. Based on the RMSE accuracy test, the ascending sequence results were radial basis <spline <IDW <local polynomial <kriging <topo to raster. Soil pH in the study area tended to increase with the decrease in slope percentage. keyword: geostatistic, interpolation, slope, soil pH, accuracy test.