The increasing population in North Kalimantan will affect the provision of land. Agricultural land conversion cannot be avoided to meet the social and economic needs of the population. To find out land conversion and its impacts in North Kalimantan, a study of a) changes in agricultural land area, b) changes in rice production and c) the effect of changes in agricultural land area on North Kalimantan rice production. Quantitative methods of secondary data analysis were carried out to assess rice production and changes in agricultural land presented in frequency tables, graphs and maps. Analysis of the effect of agricultural land area on rice production in North Kalimantan Province was carried out using linear regression analysis. The results showed that the agricultural land area in North Kalimantan in 2012-2017 had a change of 4,955 ha or around 19.56 percent.. Rice commodities in North Kalimantan in general decreased by 25,468 tons or 0.04 percent. While for agricultural land area significantly (0.029) has an effect on rice production in North Kalimantan.

Peatland forest in the Kampar peninsula have converted into various land uses, mainly converted to palm oil plantation. The massive conversion has decreased biodiversity, changed the hydrological cycle, and increased the peatland fire that dramatically decreased the quality of the peatland ecosystem. It is essential to understand the peatland characteristics and its hydrological cycle to develop sustainable peatland management. This study aimed to determine the characteristics of peat soil and the response of groundwater level to rainfall on burned peatland, mixed plantation and primary peat swamp forests in Siak district. The study was conducted from July to December 2018 by using a hydrometeorological station equipped with rainfall and groundwater level sensors. Disturbed and undisturbed soil samples were analyzed to identify the soil characteristics. The response of groundwater level to rainfall was analyzed using simple regression. The results showed that the burned peatland and mixed plantation have increased bulk density, decreased soil porosity, and caused a decrease of water infiltration. Simple regression analysis between the rainfall and the increase of GWL on the primary peat swamp forest resulted in 0.941(P)0.5106 and an R² value 0.6189, meanwhile on the burned peatland resulted in 1.2127(P)0.7818 and an R² value 0.8616, and on the mixed resulted 0.7455 in (P)0.7831 and an R2 = 0.7557.

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Daerah Aliran Sungai (DAS) Merawu di Banjarnegara terancam kelestarian lingkungannya karena erosi dan longsor. Tanah di DAS ini merupakan tanah vulkanik yang tebal dan subur. Ancaman erosi dan longsor muncul karena tanah berada pada lahan miring, intensitas hujan tinggi, dan penutupan lahan yang rendah. Erosi dan longsor sangat berkaitan dengan proses masuknya air ke dalam tanah (infiltrasi). Tujuan dari penelitian ini adalah membandingkan tiga model infiltrasi (Horton, Philip, Kostiakov) dalam memprediksi kecepatan proses masuknya air ke dalam tanah pada dua penggunaan lahan yang berbeda di DAS Merawu. Sampel tanah dan pengukuran laju infiltrasi dilakukan pada demplot: i) lahan pertanian dan ii) agrofotesri dengan masing-masing luas 0,1 Ha. Titik pengambilan sampel tanah dan pengukuran infiltrasi ditetapkan berdasarkan metode purposive sampling yang mewakili lereng bagian atas, tengah dan bawah, masing-masing sejumlah 3 titik, sehingga total ada 18 titik sampel. Pengukuran laju infiltrasi dilakukan dengan menggunakan alat Double Ring Infiltrometer. Evaluasi model menggunakan parameter statistik MAE, Bias, dan RMSE. Penelitian ini menunjukkan bahwa tanah pada demplot pertanian dan agroforestri adalah jenis Latosol dengan kelas tekstur Sandy Loam, struktur granuler, berat jenis 1,74 – 1,92 g.cm-3, berat volume 0,48 – 0,60 g.cm-3, porositas 69 – 72%, dan kandungan bahan organik 3,6-7,5%. Laju infiltrasi pada lahan pertanian dengan model Horton, Phillip, dan Kostiakov secara berturut-turut, yaitu 340 mm.jam-1, 385 mm.jam-1 dan 390 mm.jam-1. Sedangkan pada agroforestri, dengan urutan yang sama: 254 mm.jam-1, 337 mm.jam-1, dan 435 mm.jam-1. Berdasarkan nilai MAE dan RMSE, model infiltrasi Horton lebih baik dalam memprediksi laju infiltrasi pada lahan pertanian dan agroforestri.

Merawu watershed is located at Banjarnegara district and categorized as degraded watershed in the Serayu river basin. Upstream area in the Merawu watershed is a mountainous area of 1,500 m a.s.l., with steep slopes and high rainfall intensity. Upstream Merawu has an important function as recharge area, protect the downstream and water supply for the Merica reservoir. Forest conversion to intensive farming practices have produced large portion of erosion, surface runoff and water pollutant. Understanding the surface runoff changes in the forest conversion to intensive farming practices is important. Investigations of direct runoff in the intensive farming system in upstream area of Merawu watershed were observed using two small catchment experiments. Catchment for intensive farming system was compared to non-disturbed catchment of Pine forest. Surface disturbances associated with soil tillage, fertilization, pesticides and mulching during 2-3 months of planting reduced the soil capacity to control rainfall. During 1-year investigation, total direct runoff (DRO) in intensive farming catchment was 360.05 mm or 34.4% of rainfall or 1.63 times higher than that in the Pine forest catchment. Unit hydrograph analysis found the direct runoff coefficient was 9.4% or 1.7 times higher than that in the Pine forest catchment. This study found the important function of canopy interception, forest floor interception, soil management and infiltration to control the direct runoff in the catchment.