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PENGELOLAAN EKOSISTEM SAWAH

KOMPENDIUM KAJIAN LINGKUNGAN DAN PEMBANGUNAN. PENGELOLAAN EKOSISTEM SAWAH. Diabstraksikan oleh : Soemarno , PSL-PPSUB 2013. Kekeringan di Serang, Banten. Minggu, 5 Agustus 2012 08:22.

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PENGELOLAAN EKOSISTEM SAWAH

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  1. KOMPENDIUM KAJIAN LINGKUNGAN DAN PEMBANGUNAN PENGELOLAAN EKOSISTEM SAWAH Diabstraksikanoleh: Soemarno, PSL-PPSUB 2013

  2. Kekeringan di Serang, Banten. Minggu, 5 Agustus 2012 08:22 Beberapa petani membuat sumur bor di tengah sawah untuk menyelamatkan padi yang kekeringan di Kampung Astana, Ds Walikukun, Kec Carenang, Serang, Banten. Puluhan hektar sawah di lokasi itu terancam gagal panen akibat dilanda kekeringan sementara untuk membuat sumur bor tak semua petani mampu melakukannya karena harus mengeluarkan biaya tambahan. Diunduh dari: http://beritadaerah.com/denyuts/getContent/57414 ….. 31/10/2012

  3. Kekeringan Landa Pemalang, Lahan Sawah Jadi Retak-retak Sabtu, 21 Juli 2012 00:57 WIB Para petani tanaman padi di daerah Pantura (Pantai Utara), Jawa Tengah, kesulitan mendapatkan air irigasi di musim kemarau. Akibatnya, ribuan hektar tanaman padi di daerah Pemalang terancam gagal panen. Untuk menyelamatkan tanamannya, petani terpaksa harus membuat sumur bor yang disedot dengan mesin pompa air diesel. Kondisi ini menyebabkan biaya produksi meningkat. Bahkan, akibat kurangnya air irigasi ke sawah para petani, tanah sawah mengering dan retak-retak, membuat kondisi tanaman padi tidak maksimal. Jika tanah sawahnya tidak mendapatkan air, dikhawatirkan petani mengalami gagal panen. Diunduh dari: http://www.lensaindonesia.com/2012/07/21/kekeringan-landa-pemalang-lahan-sawah-jadi-retak-retak.html ….. 31/10/2012

  4. Dampak kekeringan pada tanaman padi muda Irigasi Kering, Puluhan Hektar Sawah Kekeringan (Post date: 05/07/2012 - 20:19 REPORTER: ab. EDITOR:  mdika Lebak - Sedikitnya 30 hektar lahan persawan di desa Talaga Hiang, Kecamatan Cipanas, Kabupaten Lebak, kekeringan. Dinas Pertanian Kabupaten Lebak masih terus melakukan upaya mengairi sawah warga tersebut dengan cara melakukan penyedotan air di Leuwi Herang untuk disalurkan ke saluran irigasi Leuwi Dolog. Kepala Bidang Sarana Dinas Pertanian Lebak, Rahmat Yuniar didampingi Kabid Produksi, Yuntani, mengatakan, saat ini lahan tanam petani di Desa Talaga Hiang yang luasnya mencapai 30 HA dilanda kekeringan akibat kemarau, bahkan sarana irigasi yang ada di daerah setempat yaitu Irigasi Leuwi Dolog tidak jalan sehingga  tidak dapat membantu memenuhi kebutuhan air yang dibutuhkan para  petani desa setempat DIUNDUH DARI: http://mediabanten.com/content/irigasi-kering-puluhan-hektar-sawah-kekeringan ….. 31/10/2012

  5. .5100 Hektare Sawah di Bekasi Terancam Kekeringan Posted by korantrans pada Agustus 22, 2009 . Trans, Bekasi : Akibat bencana alam yang menimpa bangunan bagi sadap (BKG/4) di daerah irigasi (DI) Kedung Gede, Desa Cipayung, Bekasi, maka seluas 5100 dari 13.000 hektare lahan sawah di daerah itu akan terncam kekeringan. Apabila tidak diatasi segera maka sejumlah petani di daerah tersebut, atau yang berada di saluran Rengas Bandung tidak bisa menggarap sawahnya karena tidak tersedianya air. Menurut Kusmana, untuk mengantisipasi agar tidak terjadinya kekeringan, maka pihaknya bekerjasama dengan Perusahaan Jasa Tirta Jatiluhur akan membuat saluran pengelak (kisdam) dengan cara pemasangan cerucuk bambu dan karung pasir. Hal ini dalakukan untuk menaikan debit ar pada saluran. Sementara untuk penanganan jangka panjangnya harus dilaksanakan pembangunan baru yang biaya fisiknya saja diperkirakan antara Rp 1 sampai Rp 2 miliar.Masalah bencana alam di BKG/4 ini sudah dilaporkan ke pusat melalui Balai Pengelola Wilayah Sungai (BPWS) Citarum di Bandung. Selain itu pihak PPK Irigasi 1 sekarang sedang melakukan koordinasi dengan pihak kecamatan dan Pemkab Bekasi, terutama dalam masalah jika ada pembebasan lahan apabila adanya pembangunan saluran baru. “ Akibaat bencana alam itu, BKG/4 ini memang perlu segera diatasi dengan pembangunan baru. Namun sebagai orang lapangan, saya usulkan pembangunannya lebih baik dilaksanakan dalam dua tahap. Hal ini mengingat waktu yang sudah mepet ke akhir tahun anggaran,” (Kusmana). Diunduh dari: http://korantrans.wordpress.com/2009/08/22/5100-hektare-sawah-di-bekasi-terancam-kekeringan/….. 31/10/2012

  6. Dampak kekeringan parah pada tanaman padi sawah SMJ

  7. PENANAMAN PADI SISTEM LEGOWO Pola TanamPada areal beririgasi, lahan dapat ditanami padi 3 x setahun, tetapi pada sawah tadah hujan harus dilakukan pergiliran tanaman dengan palawija. Pergiliran tanaman ini juga dilakukan pada lahan beririgasi, biasanya setelah satu tahun menanam padi.Untuk meningkatkan produktivitas lahan, seringkali dilakukan tumpang sari dengan tanaman semusim lainnya, misalnya padi gogodengan jagung atau padi gogo di antara ubi kayu dan kacang tanah. Pada pertanaman padi sawah, tanaman tumpang sari ditanamdi pematang sawah, biasanya berupa kacang-kacangan.

  8. SAWAH BER-TERAS-BANGKU Analysis of percolation and seepage through paddy bunds Han-Chen Huang, Chen-Wuing Liu, Shih-Kai Chen, Jui-Sheng Chen. Journal of Hydrology. Volume 284, Issues 1–4, 22 December 2003, Pages 13–25. This study investigates percolation and seepage through the bunds of flat and terraced paddies. Field experiments were conducted in Hsin-Pu of Hsin-Chu County, Taiwan, to measure the soil water content of various types of bund. Measurements revealed that the soil was unsaturated along the sloped surface of the terrace. Experimental results also indicated that seepage face flow did not develop even after 2 days of heavy rainfall. A three-dimensional model, FEMWATER, was adopted to simulate percolation and lateral seepage under various bund conditions. In a flat paddy, the rate of percolation of bunds under which a plow sole was located, was 0.40 cm d−1, close to the average infiltration rate of a flooded paddy. The percolation of the bund without plow sole was 0.85 cm d−1, or double the average infiltration rate of a flooded paddy. Infiltration in the central area of a terraced paddy is mainly vertically downward, whereas flow near the bund is predominantly lateral. The paddy field near the bund has a high hydraulic gradient. The simulated infiltration flux into the bund (1.47 cm d−1) after 85 days of rice cultivation exceeded that into the central area (0.54 cm d−1) by a factor of 2.72. The final percolation flux from the bund (1.24 cm d−1) also exceeded the final percolation from the plow sole (0.68 cm d−1) by a factor of 1.82. The lateral seepage fluxes through the bund, downward and upward along the slope surface, are 2.01 and −2.12 cm d−1, respectively. However, the lateral seepage flux does not fully saturate the surface of the hillside soil. A simulation clearly shows that the seepage upstream of the paddy field does not move water downstream and is reused as subsurface return flow. Both experimental and simulation results clarify the mechanisms of water movement in the terraced paddy and reveal the existence of an unsaturated seepage face along the sloping surface of the terraced field. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0022169403002282…….. 29/10/2012

  9. SAWAH BER-TERAS-BANGKU Analysis of percolation and seepage through paddy bunds Han-Chen Huang, Chen-Wuing Liu, Shih-Kai Chen, Jui-Sheng Chen. Journal of Hydrology. Volume 284, Issues 1–4, 22 December 2003, Pages 13–25. Two types of lateral seepage flow through bunds Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0022169403002282…….. 29/10/2012

  10. SAWAH BER-TERAS-BANGKU Analysis of percolation and seepage through paddy bunds Han-Chen Huang, Chen-Wuing Liu, Shih-Kai Chen, Jui-Sheng Chen. Journal of Hydrology. Volume 284, Issues 1–4, 22 December 2003, Pages 13–25. Schematic representation of a cross-sectional view of terraced rice field and the terminology used herein. Open arrows indicate soil water sampling locations and directions Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0022169403002282…….. 29/10/2012

  11. SAWAH BER-TERAS-BANGKU Analysis of percolation and seepage through paddy bunds Han-Chen Huang, Chen-Wuing Liu, Shih-Kai Chen, Jui-Sheng Chen. Journal of Hydrology. Volume 284, Issues 1–4, 22 December 2003, Pages 13–25. Cross-section in the vicinity of the bund of a typical flooded rice field Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0022169403002282…….. 29/10/2012

  12. SAWAH BER-TERAS-BANGKU Analysis of percolation and seepage through paddy bunds Han-Chen Huang, Chen-Wuing Liu, Shih-Kai Chen, Jui-Sheng Chen. Journal of Hydrology. Volume 284, Issues 1–4, 22 December 2003, Pages 13–25.  Model of terraced rice paddy Darcy velocity flow field for lateral seepage in the terraced paddy (cm d−1). Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0022169403002282…….. 29/10/2012

  13. Jaring-jaring Makanan dalam Ekosistem Sawah Trophic relationships in a rice ecosystem showing the importance of detritivores and non crop vegetation components. Source: The three planks for ecological engineering (Heong et al 2012) Diunduh dari sumber: http://allplantprotection.blogspot.com/2012/05/cultivating-flowers-on-rice-field-edges.html …….. 28/10/2012

  14. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Nutrient Status of Paddy Soils General Redox Transformations under Waterlogged Conditions The most characteristic management practice in paddy rice cultivation is waterlogging, or submergence of the land surface. This brings about anaerobic conditions in the soil, due to the very slow diffusion rate of oxygen through water. Biologically, after the oxygen reserve in the soil is exhausted and aerobic microorganisms have all died, facultative anaerobes dominate for some time. As the anaerobioc conditions continue, these microorganisms are gradually replaced by obligate or strict anaerobes. The biological changes are accompanied by a very characteristic succession of chemical transformations of materials. Following the disappearance of molecular oxygen, nitrate is used as a substrate for denitrifiers. Manganic oxides are solubilized as a result of reduction to manganous ions, likewise orange yellow to reddish colored iron oxides are reduced to soluble ferrous ions, decolorizing the soil. Many fermentation reactions based on various organic substrates proceed along with these mineral transformations, producing carbon dioxide, ammoniacal nitrogen, low molecular weight organic acids, and so forth. As the soil becomes even more reductive, sulfate reducers, which are strict anaerobes, produce sulfides; and methanobacteria, also strict anaerobes, produce methane. Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  15. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 All these biochemical changes occur vigorously for the first month after submergence, when readily decomposable organic matter, the energy source for microorganisms, is abundantly available. Past this stage, there will be a period when the supply of oxygen by diffusion, though extremely slow, exceeds its consumption at the soil/water interface. As all the oxygen is trapped by such reduced substances as ferrous and manganous ions at the interface, a thin oxidized, orange colored layer (normally a few millimeters thick) is differentiated from the underlying bulk of the strongly reduced, bluish-gray plow layer. Successive Chemical Transformations in Submerged Soils Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  16. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Supply of Basic Cations through Irrigation Water At least 1000 to 1500 mm of water is used to irrigate paddy fields during one rice cropping season. Nutrients dissolved in water, particularly basic cations such as calcium, magnesium and potassium, as well as silica, are supplied to rice in the water. If we assume that 1000 mm of water is used for one crop of rice, 1 mg kg -1 or 1 ppm of a substance dissolved in water amounts to 10 kg/ha. According to the mean water quality of Japanese rivers, irrigation of 1000 mm of water brings to a paddy field 88 kg/ha of Ca, 19 kg/ha of Mg, 12 kg/ha of K, and 190 kg/ha of SiO 2. Usually more than 1000 mm of water is used for irrigation, so the amount of nutrients supplied to rice is larger. Water Quality of Japanese and Thai Rivers Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  17. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Supply of Nitrogen through Biological Nitrogen Fixation There are paddy areas where rice has been cultivated for hundreds of years without receiving any fertilizer, but where yields are sustained at 1.5 to 2 mt/ha. It is estimated that about 20 kg of N is required to harvest 1 mt of paddy. Thus, it is difficult to explain how rice yields can be sustained for so long without any application of N. The greater part of N in paddy soils exists in soil organic matter. This tends to be conserved more in paddy soils than in upland soils, because of the anaerobic conditions. Microbial decomposition of the organic matter gradually releases ammoniacal N (NH 4 +-N). As NH 4 +-N is stable under anaerobic conditions, it is retained as a cation on negatively charged soil mineral and organic particles, until the time when rice roots take it up. Thus, the leaching of NH 4 +-N from paddy fields into the environment is not significant. Besides soil organic matter, there is another important source of N, i.e. biological N fixation. In paddy soils there are many microbes that are capable of fixing atmospheric N, such as blue-green algae, Clostridia, photosynthetic bacteria, and many of the heterotrophic bacteria in the rice rhizosphere. Estimates of the amount of biologically fixed N per crop of rice vary quite widely, but 30 to 40 kg/ha would be a reasonable figure. This amount of N is two or three times higher than the amount of N fixed in ordinary upland soils planted in non-leguminous crops. Interestingly enough, this amount of fixed N can explain the average yields of paddy obtained in unfertilized fields in southeast Asia (1.5 to 2 mt/ha) on the basis of 20 kg of N for 1 mt of paddy. Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  18. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Paddy soils are equipped with an excellent N cycling mechanism, with an input through biological N fixation and an output through denitrification. This appears to set the basis for sustainability of rice cultivation as an efficient food production system. Schematic Diagram of Nitrogen Cycle in Paddy Soil Ecosystem Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  19. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Negative Aspects of Soil Reduction Rice is known to suffer some physiological disorders under strongly reduced conditions. The best known is a root rot, caused by hydrogen sulfide evolved in soils that are poor in readily reducible iron oxides. These soils are often derived from pale colored, sandy, granitic sediments. They are poor, not only in iron oxides, but also in some other plant nutrients such as Mg, K and SiO 2. It is now known that root rot due to hydrogen sulfide is an acute case of the more general "akiochi" phenomenon observed in these "degraded paddy soils", as characterized above. In Japan, a nationwide project was carried out during the post-war period to ameliorate degraded paddy soils by dressing the soil with Fe-rich, more juvenile materials. With the aid of a government subsidy, the project was successfully completed, so that "akiochi" is no longer seen in Japan. There are large areas of paddy fields in southeast Asian countries that are characterized by the very low inherent potentiality of the soil. In fact, some of these deserve the name of "degraded" paddy soils. However, because of the generally low levels of both fertilizer inputs and rice yields, at present they may not be clearly differentiated from "normal" soils. Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  20. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Advantages of Paddy Rice Cultivation Comparison of Paddy Soils and Upland Soils The high level of resistance of paddy soils to erosive forces is even more important, from the viewpoint of sustainability. Upland soils tend to be eroded away unless they are properly protected. This is particularly true in the tropics, where the erosivity of rainfall is very high, and where upland soils usually have poor resistance to erosion. Paddy soils are most resistant to erosion when they are terraced and there are ridges around the field, as measures to retain surface water. In addition, paddy fields in the lowlands receive new sediments deposited from run-off that carries eroded topsoil down from the uplands, thus perpetuating soil fertility and productivity. Paddy soils have other advantages. In upland farming, crop rotation is a necessity to avoid a decline in yield due to diseases and pests that arise from a monoculture situation (soil sickness). In paddy fields, on the other hand, rice can be grown year after year without any clear sign of yield decline, over a considerable length of time. The alternation from aerobic to anaerobic conditions in a yearly cycle of rice farming is the best measure to remove the causes of soil sickness. No pathogens or soil-borne animals can survive such a drastic change in the redox environment. Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  21. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Intensification of Paddy Rice Cultivation and the Environment Rice is the staple food for more than two billion people, most of whom live in developing countries where the population is still rapidly increasing. A study conducted by the International Rice Research Institute (IRRI 1989) reveals that to meet the projected growth in the demand for rice, the world's annual rough rice production must increase from 458 million mt in 1987 to 556 million mt by 2000 and to 758 million tons by 2020. This represents a 65% increase. For the leading rice-growing countries of south and southeast Asia, the same study indicates that the increase needed in rice production by 2020 is even higher, at about double the present level. The potential for expanding the area planted in rice seems to have become very restricted in south and southeast Asia. Most land resources have already been exploited to their fullest extent, and most of the readily manageable water resources also have been developed to irrigate paddy fields. Therefore, any further increase in the production of rice depends heavily on intensification in existing rice lands. Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  22. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Impact of Irrigation/Drainage and Chemical Inputs Intensifying rice cultivation could have various impacts on the environment. If good irrigation and drainage are provided, improved rice cultivars may be introduced, along with better management of fertilizer, weeds and pests. The construction of dams, and of irrigation and drainage canals, would normally bring more benefits than disadvantages to the regional environment, as long as they are properly planned and implemented. It improves water use efficiency, regulates floods and droughts, and, through these, improves the environmental quality. Increased use of chemical preparations, such as fertilizers, pesticides and herbicides, could be more hazardous. It is possible that they might pollute irrigation water and soil, and sometimes cause human health problems. This must, however, also be evaluated in comparison with the upland cultivation of other crops. Generally speaking, paddy rice cultivation could be less hazardous to the environment if it is intensified, with a high level of chemical inputs, than upland crop cultivation. Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  23. Ecological Sustainability of the Paddy Soil-Rice System in Asia Kazutake KyumaDepartment of Environmental ScienceThe University of Shiga Prefecture2500 Hassaka-cho, Hikone CityJapan 522, 1995-09-01 Impact of Gas Emissions from Paddy Fields In relation to the global environment, air pollution from soil emissions is receiving more and more attention. The production of nitrous oxide (N 2O) from N fertilizers and manures is now considered to have an environmental impact. The gas is evolved in both nitrification and denitrification processes. The former is considered more important at present. It affects the destruction of ozone to oxygen, and also acts as a greenhouse gas. However, N 2O emissions from paddy fields are considered to be very low (De Datta and Buresh 1989). Paddy fields have been emitting methane since time immemorial. Therefore, the issue at the present time is the reason for the recent rapid increase in the atmospheric methane concentration of about 1% annually. Certainly, there was a large increase in the area planted in rice during the early postwar period, but if we take the most recent decade, 1980 to 1990, the world-wide annual rate of increase in rice area has been only 0.23% (IRRI 1993). Diunduh dari sumber: http://www.agnet.org/library.php?func=view&id=20110721171053&type_id=4 …….. 28/10/2012

  24. .. Methane emission from a simulated rice field ecosystem as influenced by hydroquinone and dicyandiamide Xingkai Xu, Yuesi Wang, Xunhua Zheng, Mingxing Wang, Zijian Wang, Likai Zhou, Oswald Van Cleemput. Science of The Total Environment, Volume 263, Issues 1–3, 18 December 2000, Pages 243–253. A simple apparatus for collecting methane emission from a simulated rice field ecosystem was formed. With no wheat straw powder amended all treatments with inhibitor(s) had so much lower methane emission during rice growth than the treatment with urea alone (control), which was contrary to methane emission from the cut rice–soil system. Especially for treatments with dicyandiamide (DCD) and with DCD plus hydroquinone (HQ), the total amount of methane emission from the soil system and intact rice–soil system was 68.25–46.64% and 46.89–41.78% of the control, respectively. Hence, DCD, especially in combination with HQ, not only increased methane oxidation in the floodwater–soil interface following application of urea, but also significantly enhanced methane oxidation in rice root rhizosphere, particularly from its tillering to booting stage. Wheat straw powder incorporated into flooded surface layer soil significantly weakened the above-mentioned simulating effects. Regression analysis indicated that methane emission from the rice field ecosystem was related to the turnover of ammonium-N in flooded surface layer soil. Diminishing methane emissions from the rice field ecosystem was significantly beneficial to the growth of rice. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0048969700007129…….. 28/10/2012

  25. .. Methane emission from a simulated rice field ecosystem as influenced by hydroquinone and dicyandiamide Xingkai Xu, Yuesi Wang, Xunhua Zheng, Mingxing Wang, Zijian Wang, Likai Zhou, Oswald Van Cleemput. Science of The Total Environment, Volume 263, Issues 1–3, 18 December 2000, Pages 243–253. Relationship between CH4 emission from rice field ecosystem amended with wheat straw and NH4+-N concentration in the floodwater (mg N l−1). Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0048969700007129…….. 28/10/2012

  26. .. Methane emission from a simulated rice field ecosystem as influenced by hydroquinone and dicyandiamide Xingkai Xu, Yuesi Wang, Xunhua Zheng, Mingxing Wang, Zijian Wang, Likai Zhou, Oswald Van Cleemput. Science of The Total Environment, Volume 263, Issues 1–3, 18 December 2000, Pages 243–253. Relationship between CH4 emission from rice field ecosystem without applying wheat straw and NH4+-N concentration in the floodwater. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0048969700007129…….. 28/10/2012

  27. SAWAH = WETLANDS Atmospheric methane (CH4) is an important greenhouse gas. On a scale of 100 years, it is approximately 20 times more effective than carbon dioxide (CO2). The total annual CH4 emission both from natural and anthropogenic terrestrial sources to the atmosphere is about 580 Tg (CH4) yr-1. The contribution of natural and man-made wetlands (e.g. rice paddy) to this global total varies between 20 and 40%. Thereby, natural wetlands are the major non-anthropogenic source of methane at present and rice agriculture accounts for some 17% of the anthropogenic CH4 emissions. This is because of the prevailing anaerobic conditions in these ecosystems, their high organic matter contents and their global distribution. Northern wetlands (>30° N) for example constitute about 60% of the global wetland area and emit a quarter to a third of the total CH4 originating from wet soils. Microbial turnover of methane and transport pathways of gases in wetlands. Diunduh dari sumber: http://www.ibp.ethz.ch/research/environmentalmicrobiology/research/Wetlands …….. 28/10/2012

  28. The value of gas exchange as a service by rice paddies in suburban Shanghai, PR China Yu Xiao, Gaodi Xie, Chunxia Lu, Xianzhong Ding, Yao Lu. Agriculture, Ecosystems & Environment. Volume 109, Issues 3–4, 1 September 2005, Pages 273–283 Valuating ecosystem services is crucial for making the importance of ecosystem functioning explicit to the public and decision makers as well as scientists. Investigations of the value of agricultural ecosystems have focused mainly on value food and fibre production and been carried out at relatively coarse scales. However, such studies may have underestimated services provided by agricultural ecosystems because they did not consider additional services such as gas regulation, pollination control, nutrient transformation, and landscape aesthetics. We present the results of a field experimental study of gas regulation services and their economic values provided by rice paddy ecosystems in suburban Shanghai, China. Two major components of gas regulation by paddy fields are O2 emissions and greenhouse gases (GHGs) regulation (including the uptake of CO2 and emissions of CH4 and N2O). Seasonal emissions of O2 from experimental plots with different urea application rates ranged from 25,365 to 32,612 kg ha−1 year−1, with an economic value of 9549–12,277 RMB ha−1 year−1 (Chinese currency; 1 euro = 10.7967 RMB, Jan 18, 2005). The net GHGs regulation ranged from 705 to 2656 kg CO2C ha−1 year−1, with an economic value ranging from 531 to 2000 RMB ha−1 year−1. Thus, the overall economic value of gas regulation provided by the rice paddy ecosystems ranged from 10,080 to 14,277 RMB ha−1 year−1. Our results refined, and in some cases, modified previous estimates of agricultural ecosystem services based mainly on coarse-scale studies. Our study also demonstrated a systematic method to valuate the gas regulation services provided by rice paddy ecosystems, which will be useful for understanding regulation of atmospheric chemistry and greenhouse effects by other agriculture ecosystems.. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0167880905001374…….. 28/10/2012

  29. The value of gas exchange as a service by rice paddies in suburban Shanghai, PR China Yu Xiao, Gaodi Xie, Chunxia Lu, Xianzhong Ding, Yao Lu. Agriculture, Ecosystems & Environment. Volume 109, Issues 3–4, 1 September 2005, Pages 273–283 . Illustration of the static chamber used to measure gas fluxes in the rice paddy fields.. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0167880905001374…….. 28/10/2012

  30. The value of gas exchange as a service by rice paddies in suburban Shanghai, PR China Yu Xiao, Gaodi Xie, Chunxia Lu, Xianzhong Ding, Yao Lu. Agriculture, Ecosystems & Environment. Volume 109, Issues 3–4, 1 September 2005, Pages 273–283 The estimated economic values of CO2 uptake, CH4 emission, N2O emission, and overall GHGs regulation from the rice paddy ecosystems during the growing season with different urea application rates in suburban Shanghai, China. The bars are the means of eight measurements ± S.D., each of which is the average of three reduplicate plots. Letters a, b, and c beside the same legend denote the significant difference in Duncan's multiple range test (at the 5% significant level) across four N treatments for CH4 emissions, or N2O emissions, or CO2 uptake or integrated CHGs regulation. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0167880905001374…….. 28/10/2012

  31. DINAMIKA NITROGEN EKOSISTEM SAWAH A coupled soil water and nitrogen balance model for flooded rice fields in India V.M. Chowdary, N.H. Rao, P.B.S. Sarma. Agriculture, Ecosystems & Environment. Volume 103, Issue 3, August 2004, Pages 425–441. In the present study a simple model for assessing concentration of nitrate in water percolating out of the flooded rice (Oryza Sativa) fields is presented. The model considers all the important nitrogen (N) transformation processes that take place in flooded rice fields such as urea hydrolysis, volatilization, nitrification, mineralization, immobilization, denitrification, crop uptake and leaching. It is based on coupling of soil water and N-balance models. The coupled model also accounts for weather, and timings and amounts of water and fertilizer applications. All the N-transformations except plant uptake and leaching are considered to follow first-order kinetics. The simulation results show that urea hydrolysis is completed within 7 days of fertilizer application. It was also observed that the volatilization loss of N varies from 25 to 33% of the applied fertilizer and 75% of the total volatilization loss occurs within 7 days of urea application. The modeled leaching losses from the field experiments varied from 20 to 30% of the applied N. The N-uptake by the crop increased immediately after the application of fertilizer and decreased at 60 days after transplanting. The model is sufficiently general to be used in a wide range of conditions for quantification of nutrient losses by leaching and developing water and fertilizer management strategies for rice in irrigated areas. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S016788090300433X …….. 29/10/2012

  32. DINAMIKA NITROGEN EKOSISTEM SAWAH A coupled soil water and nitrogen balance model for flooded rice fields in India V.M. Chowdary, N.H. Rao, P.B.S. Sarma. Agriculture, Ecosystems & Environment. Volume 103, Issue 3, August 2004, Pages 425–441. . Schematic representation of the N-transformations in flooded rice field. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S016788090300433X …….. 29/10/2012

  33. DINAMIKA NITROGEN EKOSISTEM SAWAH A coupled soil water and nitrogen balance model for flooded rice fields in India V.M. Chowdary, N.H. Rao, P.B.S. Sarma. Agriculture, Ecosystems & Environment. Volume 103, Issue 3, August 2004, Pages 425–441. . Zoning of ideal paddy field for N-balance studies. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S016788090300433X …….. 29/10/2012

  34. DINAMIKA NITROGEN EKOSISTEM SAWAH A coupled soil water and nitrogen balance model for flooded rice fields in India V.M. Chowdary, N.H. Rao, P.B.S. Sarma. Agriculture, Ecosystems & Environment. Volume 103, Issue 3, August 2004, Pages 425–441. Schematic representation of nitrogen balance model. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S016788090300433X …….. 29/10/2012

  35. DINAMIKA NITROGEN EKOSISTEM SAWAH A coupled soil water and nitrogen balance model for flooded rice fields in India V.M. Chowdary, N.H. Rao, P.B.S. Sarma. Agriculture, Ecosystems & Environment. Volume 103, Issue 3, August 2004, Pages 425–441. Nitrogen uptake in rice at Pantnagar, Uttar Pradesh, India. (a) Basal application (80 kg N ha−1) and (b) split application (40+20+20 kg N ha−1). Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S016788090300433X …….. 29/10/2012

  36. AIR DAN PADI SAWAH Rice and Water B.A.M. Bouman, E. Humphreys, T.P. Tuong, R. Barker. Advances in Agronomy. Volume 92, 2007, Pages 187–237. . Rice environments also provide unique—but as yet poorly understood—ecosystem services such as the regulation of water and the preservation of aquatic and terrestrial biodiversity. Rice production under flooded conditions is highly sustainable. In comparison with other field crops, flooded rice fields produce more of the greenhouse gas methane but less nitrous oxide, have no to very little nitrate pollution of the groundwater, and use relatively little to no herbicides. Flooded rice can locally raise groundwater tables with subsequent risk of salinization if the groundwater carries salts, but is also an effective restoration crop to leach accumulated salts from the soil in combination with drainage. Water scarcity is expected to shift rice production to more water‐abundant delta areas, and to lead to crop diversification and more aerobic (nonflooded) soil conditions in rice fields in water‐short areas. In these latter areas, investments should target the adoption of water‐saving technologies, the reuse of drainage and percolation water, and the improvement of irrigation supply systems. A suite of water‐saving technologies can help farmers reduce percolation, drainage, and evaporation losses from their fields by 15–20% without a yield decline. However, greater understanding of the adverse effects of increasingly aerobic field conditions on the sustainability of rice production, environment, and ecosystem services is needed. In drought‐, salinity‐, and flood‐prone environments, the combination of improved varieties with specific management packages has the potential to increase on‐farm yields by 50–100% in the coming 10 years, provided that investment in research and extension is intensified. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0065211304920044 …….. 29/10/2012

  37. AIR DAN PADI SAWAH Rice and Water B.A.M. Bouman, E. Humphreys, T.P. Tuong, R. Barker. Advances in Agronomy. Volume 92, 2007, Pages 187–237. . Water balance of a lowland (paddy) rice field. C, capillary rise; E, evaporation; I, irrigation; O, overbund flow; P, percolation; R, rainfall; S, seepage; T, transpiration. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0065211304920044 …….. 29/10/2012

  38. AIR DAN PADI SAWAH Rice and Water B.A.M. Bouman, E. Humphreys, T.P. Tuong, R. Barker. Advances in Agronomy. Volume 92, 2007, Pages 187–237. . Emissions of CH4 (A) and N2O (B), and combined global warming potential (C) of rice fields under continuous flooding (control), under plastic film with unsaturated soil underneath, and under straw mulch with aerobic soil conditions underneath, at three sites in China. Source: Dittert et al. (2002). Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0065211304920044 …….. 29/10/2012

  39. AIR DAN PADI SAWAH Rice and Water B.A.M. Bouman, E. Humphreys, T.P. Tuong, R. Barker. Advances in Agronomy. Volume 92, 2007, Pages 187–237. Surface and subsurface water flows across lowland rice fields. D, drainage (overbund flow); I, irrigation; P, percolation; S, seepage. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0065211304920044 …….. 29/10/2012

  40. HEMAT AIR PADI SAWAH .On-farm strategies for reducing water input in irrigated rice; case studies in the Philippines D.F. Tabbal, B.A.M. Bouman, S.I. Bhuiyan, E.B. Sibayan, M.A. Sattar. Agricultural Water Management. Volume 56, Issue 2, 30 July 2002, Pages 93–112. This paper reports results of on-farm experiments in the Philippines to reduce water input by water-saving irrigation techniques and alternative crop establishment methods, such as wet and dry seeding. With continuous standing water, direct wet-seeded rice yielded higher than traditional transplanted rice by 3–17%, required 19% less water during the crop growth period and increased water productivity by 25–48%. Direct dry-seeded rice yielded the same as transplanted and wet-seeded rice, but can make more effective use of early season rainfall in the wet season and save irrigation water for the subsequent dry season. Direct seeding can further reduce water input by shortening the land preparation period. In transplanted and wet-seeded rice, keeping the soil continuously around saturation reduced yields on average by 5% and water inputs by 35% and increased water productivity by 45% compared with flooded conditions. Intermittent irrigation further reduced water inputs but at the expense of increased yield loss. Under water-saving irrigation, wet-seeded rice out-yielded transplanted rice by 6–36% and was a suitable establishment method to save water and retain high yields. Groundwater depth greatly affected water use and the possibilities of saving water. With shallow groundwater tables of 10–20 cm depth, irrigation water requirements and potential water savings were low but yield reductions were relatively small. The introduction of water-saving technologies at the field level can have implications for the hydrology and water use at larger spatial scale levels. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0378377402000070 …….. 29/10/2012

  41. HEMAT AIR PADI SAWAH .On-farm strategies for reducing water input in irrigated rice; case studies in the Philippines D.F. Tabbal, B.A.M. Bouman, S.I. Bhuiyan, E.B. Sibayan, M.A. Sattar. Agricultural Water Management. Volume 56, Issue 2, 30 July 2002, Pages 93–112. . Schematic presentation of rice growth under four establishment systems: transplanting with seedbed in main field (A), transplanting with separate seedbed (B), direct wet seeding (C) and direct dry seeding (D). Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0378377402000070 …….. 29/10/2012

  42. HEMAT AIR PADI SAWAH .On-farm strategies for reducing water input in irrigated rice; case studies in the Philippines D.F. Tabbal, B.A.M. Bouman, S.I. Bhuiyan, E.B. Sibayan, M.A. Sattar. Agricultural Water Management. Volume 56, Issue 2, 30 July 2002, Pages 93–112. Components of the water balance of a flooded, puddled rice field. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0378377402000070 …….. 29/10/2012

  43. HEMAT AIR PADI SAWAH .On-farm strategies for reducing water input in irrigated rice; case studies in the Philippines D.F. Tabbal, B.A.M. Bouman, S.I. Bhuiyan, E.B. Sibayan, M.A. Sattar. Agricultural Water Management. Volume 56, Issue 2, 30 July 2002, Pages 93–112. Graphical presentation of the water-saving irrigation treatments of experiment 1. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0378377402000070 …….. 29/10/2012

  44. NERACA AIR SAWAH TADAH-HUJAN Water balance simulation model for optimal sizing of on-farm reservoir in rainfed farming system Dipankar Roy, Sudhindra N. Panda, B. Panigrahi. Computers and Electronics in Agriculture. Volume 65, Issue 1, January 2009, Pages 114–124. . The on-farm reservoir (OFR) is used to harvest the surplus water from the diked crop field and recycle the stored water as supplemental irrigation to rice in monsoon (rainy) and non-rice (dry) crops in winter season under rainfed farming system. A user-friendly software, using Visual Basic 6.0 program, is developed to find out the optimal size of the OFR in terms of percentage of field area (here in called as OFR sizes throughout the manuscript) by simulating the water balance model parameters of the crop field and the OFR. The software is meant for all the concerned including the engineers, planners and farming community for any monsoon influenced cropping area, which uses rainfed agriculture. The menu driven system is flexible enough to simulate the OFR sizes for various combinations of the OFR geometry, field sizes, and the cropping systems. The user has to specify the crops to be grown in the fields, irrigation management practices of the crops, types of OFR (lined or unlined), side slope, depth of OFR, and field sizes. Evapotranspiration sub-model is embedded with the main model to compute the ET from the meteorological data. As model application, the developed model is used to simulate the OFR sizes for the rice–mustard and rice–groundnut cropping systems using the experimental observed and meteorological data of the study area located at Indian Institute of Technology, Kharagpur in eastern India. The water balance model parameters of the crop field are validated with 2 years of observed data from the experimental field of above mentioned study area. The study reveals that rice–groundnut cropping system requires higher OFR sizes than rice–mustard cropping systems. Moreover, it is observed that as the field areas increase, the OFR sizes for each cropping systems is found to decrease. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0168169908001968…….. 29/10/2012

  45. NERACA AIR SAWAH TADAH-HUJAN Water balance simulation model for optimal sizing of on-farm reservoir in rainfed farming system Dipankar Roy, Sudhindra N. Panda, B. Panigrahi. Computers and Electronics in Agriculture. Volume 65, Issue 1, January 2009, Pages 114–124. Schematic presentation of water balance parameters of the rice field and the OFR with their respective control volumes. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0168169908001968…….. 29/10/2012

  46. NERACA AIR SAWAH TADAH-HUJAN Water balance simulation model for optimal sizing of on-farm reservoir in rainfed farming system Dipankar Roy, Sudhindra N. Panda, B. Panigrahi. Computers and Electronics in Agriculture. Volume 65, Issue 1, January 2009, Pages 114–124. Flow chart for computation of OFR size. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0168169908001968…….. 29/10/2012

  47. NERACA AIR SAWAH TADAH-HUJAN Water balance simulation model for optimal sizing of on-farm reservoir in rainfed farming system Dipankar Roy, Sudhindra N. Panda, B. Panigrahi. Computers and Electronics in Agriculture. Volume 65, Issue 1, January 2009, Pages 114–124. Variation of actual evapotranspiration, AET in rice field. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0168169908001968…….. 29/10/2012

  48. NERACA AIR SAWAH TADAH-HUJAN Water balance simulation model for optimal sizing of on-farm reservoir in rainfed farming system Dipankar Roy, Sudhindra N. Panda, B. Panigrahi. Computers and Electronics in Agriculture. Volume 65, Issue 1, January 2009, Pages 114–124. Variation of deep percolation in rice field. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0168169908001968…….. 29/10/2012

  49. KEHILANGAN AIR DARI SAWAH .Causes of high water losses from irrigated rice fields: field measurements and results from analogue and digital models S.H. Walker. Agricultural Water Management. Volume 40, Issue 1, 1 March 1999, Pages 123–127. In places where rice is grown in paddy fields with permanent bunds, considerable quantities of water are lost through lateral seepage of water into the bund and from there vertically to the groundwater. Lateral percolation losses increase with increases in field water depth, bund width, aquifer thickness and depth to groundwater. These losses do not occur in systems where the bunds are reformed every year. The paper discusses the areas of research required to quantify the magnitude of these `losses' at a scheme level and suggests management interventions to improve the efficiency of water use. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0378377498000924…….. 29/10/2012

  50. KEHILANGAN AIR DARI SAWAH .Causes of high water losses from irrigated rice fields: field measurements and results from analogue and digital models S.H. Walker. Agricultural Water Management. Volume 40, Issue 1, 1 March 1999, Pages 123–127.  Hypothesis: lateral percolation into and down through the bunds greatly exceeds vertical percolation through the impermeable bed of the rice fields. Diunduh dari sumber: http://www.sciencedirect.com/science/article/pii/S0378377498000924…….. 29/10/2012

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