Perubahan sifat termal tanah pasiran akibat penambahan limbah organik= (thermal properties changes of sandy soil as influenced by organic waste)

ABSTRACT Mass and heat transfer in a soil is much governed by its thermal properties. A laboratory experimentation has been done to investigate changes of thermal properties of sandy soil as influenced by organic waste mixed in the soil and the effect of the changes on soil moisture retention and evaporation. The samples of sandy soil is mixed with selected organic waste (i. e: sludge of leather industry, sludge of tapioca industry and composted green manure). The treated soil are then placed in PVC tubes, saturated with water and placed in greenhouse for measuring changes in soil properties during 50 days. Result of the experimentation shows that the organic waste mixed with sandy soil could significantly change its volumetric heat capacity and thermal regimes. The changes significantly affect the rate and amount of soil moisture loss through evaporation. During 50 days, the treated soil has lost 35 % of their soil moisture content. While the untreated (control) soil has lost 75 % of its soil moisture content. Key words: Sandy soil, thermal regimes, organic matter and soil moisture loss

Correction of time-allocation in a rotational water distribution system, based on flow characteristics in open channels

ABSTRACT A field study to determine water discharge distribution with respect to time and location as a result of rotational irrigation system has been conducted in the Maneugteung Irrigation Scheme (MIS), Cirebon, West Jawa . Data of flow characteristics in term of flow velocity and discharges under existing canal condition and system management were collected during dry season, during which a rotational water distribution system was applied in the scheme. The flow velocity and discharge of each canal section were measured by current meter. Results of the measurement then were used to develop relationships between canal length and cumulative time required to travel and to attain normal flow depth of each canal section. Result of the study reveals there was a significant time lag between the time of release and time of arrival at a particular site in the assigned open channel. This- means that irrigation water availability along the canal varies depend on water discharge, flow depth and physical condition of the canal. Attempting to obtain equity in water distribution among water users, it is suggested that the travel time and time to attain normal flow depth have to be added to the allocated time for distributing water for each irrigation block

Air Dan Masa Depan Kehidupan

Air merupakan sumberdaya alam yang sangat vital, sangat diperlukan dan menentukan keberlanjutan kehidupan di muka bumi. Bahkan menurut pandangan agama (Islam), air merupakan unsur atau elemen utama yang terlebih dahulu diciptakan Tuhan sebelum menciptakan kehidupan di bumi. Dengan air maka segala sesuatu di bumi ini menjadi hidup. Allah telah menciptakan air dan menetapkannya sebagai asal muasal kehidupan sebagaimana firmanNya : “ ...Kami telah jadikan segala sesuatu yang hidup berasal dari air” (Q.S.21: 30; 24:45 dan 25:54), bahkan air juga berperan dalam “menghidupkan” tanah (Q.S.2.164;22:5 dan 30:24). Segala sesuatu yang hidup termasuk manusia, hewan dan tumbuhan, semuanya sangat tergantung pada air untuk keberlangsungan kehidupannya (Q.S.2:164; 6:99; 22:5; 25:48-49; 56: 68-70; dan 67:30). Karena air merupakan unsur utama kehidupan, maka air adalah sumber kehidupan itu sendiri. Tak ada makhluk hidup di dunia ini yang bisa melangsungkan kehidupannya tanpa air. Air dengan volume, kualitas, lokasi dan saat tertentu sangat dibutuhkan oleh manusia dan makhluk hidup lainnya. Akan tetapi dengan volume, kualitas, lokasi dan saat tertentu yang lain, air yang bersangkutan bisa berubah menjadi ancaman yang berbahaya bagi manusia. Air dengan volume yang besar (air banjir), atau air yang bersangkutan telah tercemar oleh bahan berbahaya dan beracun, maka air tersebut berubah menjadi sesuatu yang tidak diharapkan bahkan ditakuti oleh semua orang. Air dalam keadaan yang demikian, dianggap sebagai bencana yang bisa mematikan kehidupan manusia dan makhluk hidup lainnya, bahkan bisa merubah dan menghancurkan peradaban umat manusia. Air disamping mempunyai peran dan fungsi biologis, ekologis, sosial ekonomi dan sumberdaya untuk keberlangsungan kehidupan, juga mempunyai peran dan fungsi lain seperti estetika, energi bahkan peran dan fungsi spiritual. Makalah ini membahas secara ringkas peran air untuk kehidupan, teologi pemanfaatan sumberdaya air, ketersediaan dan krisis serta konservasi air dalam perspektif ilmu

Agriculture and Irrigation System in Java During the Cultivation System

ABSTRAK Pengaruh pelaksanaan Tanam Palma terhadap perkembangan sistern irigasi dan pertanian di Jawa, merupakan pokok bahasan tulisan ini. Bahan-bahan untuk analisis dalam tulisan ini diperoleh melalui penelusuran pustaka serta laporan-laporan yang tersedia. Hasil analisis menunjukkan bahwa pelaksanaan Tanam Paksa telah secara nyata merubah pola pergiliran tanaman serta produksi tanaman pangan di lahan sawah beririgasi. Perubahan ini sebagai akibat daRI terlalu lamanya lahan sawah dikuasai oleh pabrik gula untuk tanaman tebu, prioritas pembagian air untuk tebu dan pabrik gula serta pengerahan tenaga kerja petani yang berlebihan untuk kegiatan-kegiatan yang berkaitan dengan produksi gula. Disamping itu, pada satu sisi, Tanam Paksa telah mendorong berkembangnya sistem irigasi modern di Jawa yang mempunyai ciri-ciri sistem keteknikan dan manajemen yang berbeda dengan sistem irigasi tradisional. Akan tetapi pada sisi lain, semakin menghilangkan hak dan keterlibatan petani dalam kegiatan-kegiatan operasional sistem irigasi moder

Kajian kehandalan teknologi irigasi air tanah untuk usaha tani sistem sorjan di Kabupaten Kulon Progo=A study reliability of ground water irrigation for ste sorjan ...

A technology of ground water irrigation for sorjan farming system has been applied by farmers in Kecamatan Panjatan, Kabupaten Kulonprogo for years. The technology is simple and indigenous but there is no such infOrmation concerning it reliability and appropriateness. The aims of the study are to examine the reliability of the ground water irrigation for soda\u27, farming Spiem and factors influence performance of the technology. The reliability is examined by the productivity of land and waler use, irrigation effectiveness and farmers income from the sorjan farming system. The study is conducted by survey and field observation method, includes physical characteristics of the sorjan land, ground water level, interval of wells ernd cropping pattern. Labour used for irrigation perday, time consumed for one irrigation, irrigation capacity perday and irrigation effectiveness are observed in the field during the working days. Crops production and irrigation cost, crops yield and famers income from sorjan farming are investigated through field survey. Two locations of sorjan farming are selected as the the sample locations for the study. The study concludes that the sorjan farming under crops rotation of rice and vegetable in the furrows and vegetable crops for all season on the ridges performs as a productive and adaptive land and water use for agriculture. The technology of ground water irrigation for the sorjan farming is considered as a reliable technology from the point view of adaptability to the local environment, water availability, irrigation effectiveness and farmers income per year from sorjan farming . Besides that. the technology is developed by the local farmers based on their wise and experiences to local circumstances and therefore, more appropriate and sustainable. Key words :Ground water irrigation, adaptive, reliable and appropriate technology

The Clay Content Effect on The Formation of Shallow Mole Drainage and The Rate of Lowering Soil Moisture Content

Installing shallow mole drainage in the soil is infl uenced by various factors, namely; the physical properties of soil and tools which are used. One of the physical properties of soil that infl uences the formation of the mole drainage is the clay content of soil. This study aimed to explore the condition of the mole drainage formed in paddy soil with different clay contents. The study was conducted in a laboratory scale using a soil bin, a model of mole plough, and soil which was kept homogeneous in the boxes. The experiment was conducted at the Laboratory for Energy and Agricultural Engineering, Agricultural Engineering Department, Universitas Gadjah Mada, Yogyakarta. Mole drainage was installed in 3 paddy soils with different clay content, namely; 13.12% (soil A; loam soil), 41.17% (soil B; clay soil) and 53.36% (soil C; clay soil). The study was conducted by analyzing the geometry of the mole drainage and observing the soil deformation which occurred due to the formation of the mole drainage. The study showed that perfect mole drainages were installed in all of those three types of soil. The mole drainages were quite good and stable with little cracks. Based on the soil crack and fi ssuring of soil, the largest soil deformation has occurred in soil with the highest clay content and the smallest one in soil with the lowest clay content. The characteristics of those three installed mole drainages were almost the same, but they had different effect on the rate of lowering soil moisture content. Here, the mole drainage installed in loam soil is different from which of installed in clay soil. The mole drainage installed in the loam soil did not infl uence the rate of lowering soil moisture content. Contrary, the mole drainage installed in clay soil has effected to increase the rate of lowering soil moisture content

Kesesuaian Model Infiltrasi Philips untuk Prediksi Limpasan Permukaan Menggunakan Metode Bilangan Kurva

The objective of this study was to determine suitability and applicability of the Philips infi ltration model for predicting surface runoff using the Curve Number method. The data of infi ltration rate obtained from direct measurements in the fi eld on a variety of land use in the upper Progo sub watershed using double ring infi ltrometer method. Soil samples also taken for determination of physical properties at each location of infi ltration measurement. Data of landuse, rainfall, and river discharge were collected from the available data at Balai PSDA Progo Bogowonto Luk ulo and BP DAS Serayu Opak Progo. Test results showed that Philips infi ltration model was suitable for predicting surface runoff using curve number method. The suitability was examined by signifi cancy of deterministic coeffi cient, correlation coeffi cient, the mass balance, and the distribution of t.ABSTRAKPenelitian ini bertujuan untuk menganalisis kesesuaian model infi ltrasi Philips untuk prediksi limpasan permukaan menggunakan metode bilangan kurva. Data laju infi ltrasi diperoleh dari pengukuran langsung di lapangan pada berbagai macam penggunaan lahan di Sub DAS Progo Hulu menggunakan metode double ring infi ltrometer. Dilakukan pula pengambilan contoh tanah untuk penentuan sifat fi siknya di masing-masing lokasi pengukuran infi ltrasi. Sedangkan data luas penggunaan lahan, hujan, debit sungai digunakan data yang tersedia di Balai PSDA Progo Bogowonto Luk ulo dan BP DAS Serayu Opak Progo. Hasil pengujian menunjukkan bahwa model infi ltrasi Philips cukup sesuai digunakan untuk prediksi limpasan permukaan menggunakan metode bilangan kurva. Kesesuaian ini dilihat dari nilai koefi sien deterministik, koefi sien korelasi, imbang massa, dan distribusi t yang signifi kan

Aplikasi Model AVSWAT2000 untuk Prediksi Limpasan Permukaan, Erosi, dan Sedimentasi di Sub DAS Keduang: DAS Bengawan Solo Hulu

Data laju erosi yang diperoleh dari model hidrologi dapat digunakan dalam pengambilan keputusan untuk menentukanusaha konservasi lahan yang dapat mengurangi laju erosi yang terjadi di DAS. Model hidrologi yang dipergunakan dalam penelitian ini adalah model AVSWAT2000 (Arc View Soil and Water Assessment Tools 2000) yang dapatmemprediksi limpasan permukaan, erosi dan sedimentasi. Penelitian ini dilakukan di sub DAS Keduang (36.574,34Ha). Hasilnya menunjukkan bahwa, besarnya limpasan permukaan, erosi dan sedimentasi di sub DAS Keduang padakondisi saat ini masing-masing sebesar 424,09 mm, 87,87 ton/ha/th, dan 375,07 ton/th. Dengan melakukan Perubahanpenggunaan lahan jumlah limpasan permukaan, erosi dan sedimentasi bisa mengalami penurunan, di sub DAS Keduanglaju limpasan permukaan, erosi dan sedimentasi menurun masing-masing menjadi 412,61 mm, 36,78 ton/ha/th, dan353,60 ton/th

Aplikasi Model AVSWAT2000 untuk Prediksi Limpasan Permukaan, Erosi, dan Sedimentasi di Sub Das Keduang: Das Bengawan Solo Hulu

Erosion rate data obtained from the hydrological model can be used in making decisions to determine which landconservation efforts can reduce the rate of soil erosion in the watershed. The hydrologic model applied is AVSWAT2000(Arc View Soil and Water Assessment Tools 2000) to predict surface runoff, erosion, and sedimentation. This studywas conducted at sub watershed Keduang (36.574,34 Ha). The results indicated that surface runoff, erosion, andsedimentation in Keduang watershed at the existing condition are 424,09 mm, 87,87 ton/ha/th, and 375,07 ton/th,respectively. By simulation be adjusting the land use scenario, the surface runoff, erosion, and sedimentation rate couldbe reduce to become : 412,61 mm, 36,78 ton/ha/th, 353,60 ton/th, respectively, In Keduang watershed.ABSTRAKData laju erosi yang diperoleh dari model hidrologi dapat digunakan dalam pengambilan keputusan untuk menentukanusaha konservasi lahan yang dapat mengurangi laju erosi yang terjadi di DAS. Model hidrologi yang dipergunakan dalam penelitian ini adalah model AVSWAT2000 (Arc View Soil and Water Assessment Tools 2000) yang dapatmemprediksi limpasan permukaan, erosi dan sedimentasi. Penelitian ini dilakukan di sub DAS Keduang (36.574,34Ha). Hasilnya menunjukkan bahwa, besarnya limpasan permukaan, erosi dan sedimentasi di sub DAS Keduang padakondisi saat ini masing-masing sebesar 424,09 mm, 87,87 ton/ha/th, dan 375,07 ton/th. Dengan melakukan perubahanpenggunaan lahan jumlah limpasan permukaan, erosi dan sedimentasi bisa mengalami penurunan, di sub DAS Keduanglaju limpasan permukaan, erosi dan sedimentasi menurun masing-masing menjadi 412,61 mm, 36,78 ton/ha/th, dan353,60 ton/th