Paddy Field

Different weeding frequencies (WFs)―0WF, 2WF, 4WF, 6WF, and 8WF―were adopted in an organic rice field to investigate their influence on weed types, rice and weed biomass, rice tiller and weed number, N concentration, and N uptake. The study field was located in Tsuruoka, Yamagata, Japan. Rice (cv. Sasanishiki) was planted from May to September 2019, and all weeding events were carried out until 49 days after transplantation (DAT) using a rotary weeder. Rice and weed samples were collected at 60, 88, and 110 DAT. Echinochloa crus-galli (E. crus-galli), Schoenoplectus juncoides, and Monochoria vaginalis (Burm. f.) were the most commonly found weeds. High weed diversity was observed at both 6WF and 8WF, E. crus-galli was the dominant weed at 0WF. Compared to 0WF, 2WF displayed a significantly decreased weed biomass. However, at 8WF, the weed biomass was reduced by 79.0%, the rice biomass was increased by 277%, and the rice tiller number was almost three times higher than that at 0WF an...

This study is the first global effort to quantify seasonality and extent of inundation with a suite of satellite observations, including passive and active microwave along with visible and infrared measurements. A clustering technique which merges the satellite observations is used to detect inundation. Monthly flooded areas are then calculated by estimating pixel fractional coverage of flooding using the passive microwave signal and a linear mixture model with end-members calibrated with radar observations to account for vegetation cover. The global results, comprising natural wetlands, irrigated rice, and lakes/rivers, indicate a minimum inundated area for the July 1992-June 1993 period of 2.16x10 6 km 2 , about 38% of the maximum 5.75x10 6 km 2 , to be compared to maximum areas of 5.83x10 6 km 2 and 5.70x10 6 km 2 from independent data sets. Comprehensive evaluation requires substantial additions to the sparse observational record now available.

Biogenic sulfur gases emitted from Chinese rice paddies were measured with a laboratory incubation and a closed chamber method in the field. Six speciations of sulfur-containing gases were detected in both conditions: hydrogen Ž . Ž . Ž . Ž . Ž sulfide H S , carbonyl sulfide COS , methyl mercaptan CH SH , carbon disulfide CS , dimethyl sulfide CH SCH 2 3 2 3 3 . Ž . or DMS and dimethyl disulfide CH SSCH or DMDS . Among them, DMS comprised the major part of the sulfur 3 3

The spatial distributions of contaminant metals (Hg, Pb, Zn, Cd, Cu) and a metalloid (As) in vegetable plots and paddy fields located near a large scale Pb/Zn smelter in Hunan province, China, were investigated. Soil located 4 km from the smelter was severely contaminated, with maximum concentrations of Hg, Pb, Zn, Cd, Cu and As as high as 2.89, 1200, 3350, 41.1, 157 and 93 mg kg À1 , respectively. Concentrations of soil metal and As decreased with distance in the dominant wind direction. Single-factor assessment indicated pollution levels of Hg, Pb, Zn and Cd were most severe, while pollution levels for Cu and As were less severe. Results from a potential ecological risk assessment indicated high risk associated with the soil within a 4 km radius, with the contribution for each contaminant calculated as follows: Cd (70.0%), Hg (19.4%), Pb (4.8%), As (3.0%), Cu (1.7%) and Zn (1.1%). The forest soil in the nearby city park was also affected by the atmospheric depositions from smelting activities. Soil profiles demonstrated the pollutants were mostly accumulated in the upper 20 cm layer. Contamination of the topsoil with Hg, Pb, Zn, Cd, Cu and As indicated remediation should be considered.

Nitrogen (N) loss through ammonia volatilization from paddy fields at three sites in Vietnam was measured using the dynamic chamber method. Two sites were located in northern Vietnam and volatilization was measured in the summer and spring. The third site was in the Mekong Delta region in southern Vietnam and volatilization was measured in the dry and wet seasons. Urea was applied at 20–40 kg N ha−1 as a split application and a total of 80–100 kg N ha−1 was applied in the cropping season. Peaks in the NH3 flux were observed at 1 or 3 days after the application of urea, followed by a sharp decline to generally less than 1 mg N m−2 h−1 within 9 days. The estimated N losses by NH3 volatilization during the first 10-day period after fertilizer application and throughout the cropping period were 0.5–19.7% and 1.7–14.6% of the applied N, respectively, indicating that NH3 volatilization was a significant pathway of N loss from these Vietnamese paddy fields.

A number of experimental freshwater wetlands (150 m long ϫ 75 m wide) with different ages since they were abandoned as rice fields, were used to analyze the prospects of multipurpose wetland restoration for such degraded areas. Nitrogen and phosphorus removal rate of the wetlands were determined monthly during the flooding season to estimate their efficiency as filters to remove nutrients from agricultural sewage. The number of wetland birds was recorded regularly to identify their habitat preferences. Both the temporal dynamics and changes in the spatial pattern of land use cover during the last 20 years were determined from aerial photographs and field analysis. All the wetlands appeared to be very efficient in the removal of nitrogen and phosphorus exported from rice fields. Usually 50-98% of the nitrogen and less than 50% of the soluble phosphorus were removed by the wetlands at any stage of restoration. Wetland birds preferred wetlands with intermediate plant cover for resting and sleeping activities better than rice fields and either very open wetlands or very dense ones with tall vegetation. Apart from the improvement in water quality and the restoration of natural habitats, restoration of wetland belts around lagoons will increase spatial heterogeneity and diversity of the landscape.

Since the productivity of soybean in Indonesia is still low, a new innovation is needed to improve it. The objectives of this study are to determine a pattern of the stomatal opening of soybean's leaves which exposed by high-frequency sound waves with different duration time and age of soybean plants. This study was carried out at the Experimental Farm Agriculture Faculty and Biology Laboratory of Science Faculty of the Islamic University of Malang, East Java in April to August 2013.The first factor was duration time of the exposure which consist of three levels: 20 minutes (D 1), 40 minutes (D 2) and 60 minute (D 3).The second factor was the age of the soybean which consist of three levels: 15 days after planting (dap) (A 1), 25 dap (A 2) and 35 dap (A 3). The soybean plants were exposure by the 5000 hertz frequency. The variables measured consisted of stomatal opening width, plant height, leaf area, fresh weight of pods, fresh weight of seed, oven dry weight of beans and harvest index. Increase of the duration time of exposure of high frequency sound waves by 20 to 60 minutes, tends to decrease the width of stomatal opening. The treatment of duration of exposure by 40 minutes at the age of 15 dap had the highest soybean grain yield by 24.10 g.plant-1 , equivalent to 3.93 ton.ha-1. The relationship between the widths of the stomatal opening with soybean production showed no significant correlation. The results of this study suggest that maintaining stomatal opening at optimum width through the manipulation of high-frequency sound waves will increase the yield of soybean plants.

It has been stated that the quality of the aromatic rice variety, Khao Dawk Mali 105 is influenced by the environment of the production area or cultivation method. In this study, 2-acetyl-1-pyrroline content of various rice samples in Thailand was investigated. The results showed that the samples from the Northeastern region, where Khao Dawk Mali 105 was cropped in rain-fed paddy fields, were higher in 2-acetyl-1-pyrroline content. The "Tungkularonghai" area, stated as being the highest quality rice production area, had the highest content among the areas in Northeastern Thailand. Samples collected from non-drought condition areas showed lower content even in the Tungkularonghai area. However, differences in seeding method did not affect 2-acetyl-1-pyrroline content in the Tungkularonghai area. These results showed that dry climate might be a factor for 2-acetyl-1-pyrroline content in Khao Dawk Mali 105. Since Khao Dawk Mali 105 is a photosensitive variety, it was expected that the ripening stage becomes uniform at a certain period which should be suitable for 2-acetyl-1-pyrroline formation in paddy fields.

The fate and transport of tricyclazole and imidacloprid in paddy plots after nursery-box application was monitored. Water and surface soil samples were collected over a period of 35 days. Rates of dissipation from paddy waters and soils were also measured. Dissipation of the two pesticides from paddy water can be described by first-order kinetics. In the soil, only the dissipation of imidacloprid fitted to the simple first-order kinetics, whereas tricyclazole concentrations fluctuated until the end of the monitoring period. Mean half-life (DT 50 ) values for tricyclazole were 11.8 and 305 days, respectively, in paddy water and surface soil. The corresponding values of imidacloprid were 2.0 and 12.5 days, respectively, in water and in surface soil. Less than 0.9% of tricyclazole and 0.1% of imidacloprid were lost through runoff during the monitoring period even under 6.3 cm of rainfall. The pesticide formulation seemed to affect the environmental fate of these pesticides when these results were compared to those of other studies.

This paper assesses strategic water availability and use under different development pathways on a basin scale using remote sensing (RS), geographical information systems (GIS) and a spatial water budget model (SWBM). The SWBM was applied to the Upper Ing Basin in northern Thailand to investigate the spatial and temporal variations in the location of streams and water yields from different parts of the basin. The base simulation was carried out for the years 1998-2007 using a DEM and actual land-use data at 100-m resolution. The simulated stream network was compared with topographic maps under different flow conditions, which were successfully represented. The 10-year average simulated river flow rate was 1300 L/s, but it more than doubled during periods of heavy rainfall and decreased below 600 L/s in dry seasons. The total length of the streams (based on flow threshold of 25 L/s) on a typical day in the dry season differed by a factor of approx. 1.5. Agricultural water needs and possible extraction were assessed and presented by dividing the basin into 10 different zones based on the stream network. The results show that there is the potential for harvesting significant quantities of water at different spatial gradients with no initial water supply for irrigation. Monthly water yields for each zone were computed; the results varied from less than 50% to over 137% of the per hectare water yield for the entire basin. This variation was due to differences in topography and land cover. The impact of land use and climate change on streamwater availability was also studied. The basin shows very different hydrological responses. The changes in average river flow relative to the base simulation were +27.6%, −32.1%, +94% and +52.9% under deforestation, changing land use from paddy field to orchard, bare soil and increased rainfall scenarios, respectively.

Ageratum conyzoides L. (billy goat weed), showed strong inhibition on Raphanus sativus L. (radish) germination and growth in a bioassay. The leaves exhibited a greater suppression than the stem and root. The leaves of A. conyzoides applied at 2 t ha À1 reduced about 70% of the growth of Echinochloa crus-galli var. formosensis Ohwi. and completely inhibited emergence of Monochoria vaginalis (Burm.f. Persil var. plantaginea Solms.) and Aeschynomene indica L. in calcareous soil condition. Application of A. conyzoides leaves at 2 t ha À1 in a paddy field 2 d after transplanting caused about 75% paddy weed reduction and increased yield by 14% compared with a herbicide treatment. Three phenolic compounds were identified in the leaves, stem and root including gallic acid, coumalic acid, and protocatechuic acid, and catechin was found only in the stem. p-hydroxybenzoic acid was detected in both A. conyzoides leaves and stem. Three additional putative allelochemicals were found in the leaves consisting of p-coumaric acid, sinapic acid, and benzoic acid. The greater number of growth inhibitors found in the leaves might result in the stronger inhibitory activity than the stem and root. A. conyzoides might be a natural herbicide for weed control in paddy fields to reduce the dependence on synthetic herbicides. r

Golf courses have historically been seen as places of heavy pesticide and fertilizer use, however, there are few scientific studies on the ecology of golf courses. The aim of this study was to assess the value of golf courses for conserving forest biota in urban landscapes.

The Sundarban, covering about one million ha in the delta of the rivers Ganga, Brahmaputra and Meghna is shared between Bangladesh (~60 %) and India (~40 %), and is the world's largest coastal wetland. The area experiences a subtropical monsoonal climate with an annual rainfall of 1,600-1,800 mm and severe cyclonic storms. Enormous amounts of sediments carried by the rivers contribute to its expansion and dynamics. Salinity gradients change over a wide range of spatial and temporal scales. The biodiversity includes about 350 species of vascular plants, 250 fi shes and 300 birds, besides numerous species of phytoplankton, fungi, bacteria, zooplankton, benthic invertebrates, molluscs, reptiles, amphibians and mammals. Species composition and community structure vary east to west, and along the hydrological and salinity gradients. Sundarban is the habitat of many rare and endangered animals (Batagur baska, Pelochelys bibroni, Chelonia mydas), especially the Royal Bengal tiger (Panthera tigris). Javan rhino, wild buffalo, hog deer, and barking deer are now extinct from the area. Large areas of the Sundarban mangroves have been converted into paddy fi elds over the past two centuries, and more recently into shrimp farms. The Sun-

Soil saturated hydraulic conductivity (Ks) is an important soil physical property. Some laboratory and field methods are expensive, time consuming and labour intensive. Indirect methods such as pedo-transfer functions (PTF) are available. Effective porosity or macroporosity (Øe) is approximately equals to porosity minus volumetric soil water content at the field capacity. According to Kozeny–Carman equation, Ks could be evaluated using Øe. Franzmeier estimated the Ks from Øe based on Ahuja et al. He found a strong relationship between Øe and Ks. This paper presents results of a study to characterize the effective porosity in lowland paddy fields and to show the possibility of using the effective porosity (Øe) in estimating the saturated hydraulic conductivity (Ks). Soil in lowland paddy fields forms its horizon as topsoil, hardpan and subsoil. Soil samples were collected randomly within a 2300-ha rice cultivation area where there are five dominant soil series. A total of 408 soil samples were taken from 136 sampling points and at three depths, namely, the topsoil, hardpan and subsoil. Ks values were measured in the laboratory using the falling head method. Soil bulk density and moisture content at −66 kPa were determined. The Øe was then calculated using the difference of the total porosity (Ø) minus the volumetric moisture content at −66 kPa. The Ks values ranged from 5.35×10−4 to 8.77×10−2 m day−1. The Db varied from 0.62 to 1.91 Mg m−3, and the values of the Dp ranged from 1.10 to 2.89 Mg m−3. The Ø ranged from 0.17 to 0.68 m3 m−3. The results of the Øe of the samples in this study were obtained by calculating the difference of the total porosity and volumetric moisture content at field capacity. For clayey soils, field capacity is taken at the suction of −66 kPa. The Øe varied from 0.05 to 0.55 m3 m−3, with the mean value of 0.24 m3 m−3. The regression equation of a power function shows a highly significant regression coefficient, r2 of 0.50 (n=400). This indicates that there is a strong relationship between Ks and Øe for the lowland paddy soils in the study area.

In order to analyze the mitigation of methane (CH 4 ) emissions and the global warming potentials (GWPs) of CH 4 and nitrous oxide (N 2 O) emissions from paddy fields by modifying the adopted water-management technique, we conducted field experiments to measure the CH 4 and N 2 O fluxes at nine sites across Japan.

Chakhao (Black rice; Oryza sativa L.) is one of the lesser known traditional rice varieties of Manipur which provides not only nutraceutical benefits, but also plays a significant role in socio-cultural practices of the local Meitei community. This paper describes indigenous agro-ecological knowledge and socio-cultural practices of Meitei farmers associated with black rice cultivation. A total of 72 knowledge holders were identified through chain referrals method in three representative villages in Imphal East district of Manipur. Semi-directive interview and group discussion methods were employed for documentation of their knowledge and socio-cultural practices. In all four black rice landraces (viz., Chakhao poireiton, Chakhao angouba, Chakhao amubi and Chakhao pungdol amubi) were recorded in the study area. About 57 % of the farmers in the study area cultivated black rice in < 10 % of their land holdings. According to the farmers all these landraces of black rice are relatively stress tolerant and disease resistant and require less care and energy inputs. Black rice is used in different religio-cultural feasts and rituals of Meiteis. Beside it is also used as a medicine for diabetic patients and traditionally given to pregnant women. Cultural practices of Meiteis help conserving the agro-biodiversity in the study area.

Paddy (Oryza sativa L. var. Taiching-127) fields of Kirtipur, central Nepal, were studied to evaluate the effects of weeds on crop yield during June to October 2003. Weed community was recorded in permanently marked plots (2 x 2 m 2 each), and grain and straw yields were measured. The effect of aqueous extracts (2 to 10%) of leaf, stem and root of dominant weeds (Echinochloa colona, E. crusgalli, Cyperus iria and Ageratum conyzoides) on germination and seedling growth of the paddy (Taiching-127) was examined in the laboratory. Altogether 52 weed species (27 dicot and 25 monocot) belonging to 32 genera and 15 families infested the paddy. The maximum weed density was observed in September (105 pl/m 2 ). There was significant reduction in straw and grain yield of paddy in weedy plots and negative correlation between weed species richness and straw yield. Crop weed competition reduced straw yield by 13% to 38% and grain yield by 25% to 47%. Weed growth changed pH and reduced soil nitrogen and phosphorus content. Aqueous extracts of root, stem and leaf of dominant weeds (Echinochloa colona, E. crus-galli, Cyperus iria and Ageratum conyzoides) showed a weak effect on seeds germination however most of them had inhibitory effect on root and shoot elongation of paddy seedlings. Root elongation was more sensitive to allelopathic inhibition than shoot elongation. Stem extract of these weeds showed higher inhibition on seedling growth of paddy than leaf and root extract except in Ageratum conyzoides in which root extract showed highest inhibition.

The Sundarban, covering about one million ha in the delta of the rivers Ganga, Brahmaputra and Meghna is shared between Bangladesh (~60 %) and India (~40 %), and is the world's largest coastal wetland. The area experiences a subtropical monsoonal climate with an annual rainfall of 1,600-1,800 mm and severe cyclonic storms. Enormous amounts of sediments carried by the rivers contribute to its expansion and dynamics. Salinity gradients change over a wide range of spatial and temporal scales. The biodiversity includes about 350 species of vascular plants, 250 fi shes and 300 birds, besides numerous species of phytoplankton, fungi, bacteria, zooplankton, benthic invertebrates, molluscs, reptiles, amphibians and mammals. Species composition and community structure vary east to west, and along the hydrological and salinity gradients. Sundarban is the habitat of many rare and endangered animals (Batagur baska, Pelochelys bibroni, Chelonia mydas), especially the Royal Bengal tiger (Panthera tigris). Javan rhino, wild buffalo, hog deer, and barking deer are now extinct from the area. Large areas of the Sundarban mangroves have been converted into paddy fi elds over the past two centuries, and more recently into shrimp farms. The Sun-

The Vercelli rice district in northern Italy plays a key role in the agri-food industry in a country which accounts for more than 50% of the EU rice production and exports roughly 70%. However, although wealth and jobs are created, the sector is said to be responsible for environmental impacts that are increasingly being perceived as topical. As a complex and comprehensive environmental evaluation is necessary to understand and manage the environmental impact of the agri-food chain, the Life Cycle Assessment (LCA) methodology has been applied to the rice production system: from the paddy field to the supermarket. The LCA has pointed out the magnitude of impact per kg of delivered white milled rice: a CO 2eq emission of 2.9 kg, a primary energy consumption of 17.8 MJ and the use of 4.9 m 3 of water for irrigation purposes. Improvement scenarios have been analysed considering alternative rice farming and food processing methods, such as organic and upland farming, as well as parboiling. The research has shown that organic and upland farming have the potential to decrease the impact per unit of cultivated area. However, due to the lower grain yields, the environmental benefits per kg of the final products are greatly reduced in the case of upland rice production and almost cancelled for organic rice. LCA has proved to be an effective tool for understanding the eco-profile of Italian rice and should be used for transparent and credible communication between suppliers and their customers.

This paper reviews archaeobotanical records on the beginning and spread of rice agriculture in the Korean peninsula. Argument for the earliest evidence of domesticated rice at the Sorori site, 15,000 years ago, is invalid. The evidence for rice cultivation in the Neolithic (Chulmun) is still insufficient although rice remains have been reported from a few late Neolithic sites in central-western Korea which dated to about 3000 BC. The existence of rice agriculture in the Bronze Age (Early and Middle Mumun: c.1300∼300 BC), on the other hand, is demonstrated by the high percentage and/or frequency of rice remains among crops recovered from various sites, as well as through the numerous findings of paddy fields. Rice appears to have been introduced from the Liaodong region, China, while so called 'southern diffusion route' that the beginning of rice cultivation was first stimulated by influences from Southeast Asia or South China is no more valid. Charred rice remains recovered from the Bronze Age dwellings consist of dehusked clean grains and weedy seeds are very rare among samples containing rice grains, which could be related with the harvesting and processing methods of rice. Measurements of charred rice grains also will be reported in this paper. Agricultural villages disappear from the archaeological records from the third century BC, which corresponds to the beginning of the Early Iron Age (Late Mumun), and reappear from the late first century with the emergence of urban societies.

A minimum tillage technique is required for reducing the labor requirements to prepare a level rice seedbed in Korea. Thus this study was aimed at determining the strip tillage characteristics of rotary tiller blades for use in a dryland direct rice seeder. The experiments were carried out in a laboratory soil bin. The USDA textural classification of the experimental soil was sandy loam. Soil hardness measured by cone penetrometer ranged from 245 to 1442 kPa depending on the depth, and the soil moisture content was 34.6%.The effects of rotary blade shape, rotational direction, number of rotary blades around the periphery, with and without soil-cutting disc blades on soil break up and torque requirements were investigated. Three different types of rotary blade were used, two general purpose rotary blades used with tractors and power tillers, and a leveling rotary blade for tractor use in wetland paddy fields. Rotation in the opposite direction to travel and cutting upwards resulted in soil being scattered out of the seeding furrow. A down-cut process is therefore necessary for effective seedbed preparation of a rice field by strip tillage using a rotary tiller. Of the three types of rotary blade, the rotary blade for the power tiller was considered most satisfactory for strip tillage on a basis of its torque requirement and the ratio of soil breaking. The rotor shaft with four rotary blades had the lowest torque variation and torque requirement and ratio of soil breaking was 24.4%. The width of seedbed prepared by the rotary tiller with four blades during the down-cut process was 80 mm which was enough for direct seeding of rice and applying fertilizer. Though a soil-cutting disc blade helped produce a better seedbed furrow, the increased friction between the disc blade and the soil block generated a much higher torque requirement. The soil-cutting disc blade was not necessary for the strip tillage direct rice seeder. Based on the results a strip tillage technique by the power tiller blade with a down-cut process could be effectively used for a dryland direct rice seeder.

Golf courses have historically been seen as places of heavy pesticide and fertilizer use, however, there are few scientific studies on the ecology of golf courses. The aim of this study was to assess the value of golf courses for conserving forest biota in urban landscapes. The biota occurring in 12 Japanese golf courses and their surrounding areas was investigated. Investigations were done at golf course sites located on the green, fairway, rough, green belts between holes, and the out of bounds forest. Roadside, paddy fields, park and forest sites were investigated outside the golf courses. Presence/absence data for plants, arthropods and vertebrates in each sample habitat were analysed by TWINSPAN. As a result, communities in golf courses were classified by the part of course (e.g. green, fairway), and not by the location of the course nor chemical use. However, differences between golf courses in urban and rural landscapes were detected in the biota of the whole course. The out of bounds forest of golf courses was similar to forests that exist outside the courses, and this area held more flora and fauna than turf vegetation and artificial biotopes outside the course such as roadside and paddy. This suggests that golf courses in urbanised areas can be a refuge for flora and fauna, since forest cover occurs in only limited proportions in urban landscapes. Furthermore, the application of regulations for golf course construction seemed to be useful in maintaining forest species on golf courses. This may contribute to the conservation of native forest biota within Japanese urban landscapes.

A study was undertaken to determine the freeliving culturable diazotrophic bacteria of paddy soils from a long-term fertilizer management experiment. Long-term application of different fertilizers significantly affected the population of free-living diazotrophs. Out of 165 distinct bacterial morphotypes observed during the isolation process, only 32 were positive for both acetylene reduction assay (ARA), and nifH gene screening. The ARA activity of the isolates ranged from 1.8 to 2,844.7 nmol ethylene h −1 mg protein −1. The 16S rRNA analysis identified the isolates to be members of 13 different genera viz.

In recent years, environmental impacts of energy consumption in different production systems have become more adverse. Agricultural systems, as results of food security and production growth, are nowadays significant energy consumers. Owing to various reasons, energy consumption in these systems , especially those in developing countries, are often inefficient. As such, there are three objectives in this study. The first objective is the assessment of energy flow, cumulative exergy demand and life cycle of paddy fields. The second goal is the optimization of energy consumption by employing Data Envel-opment Analysis (DEA) and Multi-Objective Genetic Algorithm (MOGA) for enhancement of energy efficiency (reduction in energy consumption and increase performance in paddy production) and reduction of adverse environmental effects in paddy production. The third objective is the provision of the optimum pattern of energy consumption in paddy production in Guilan Province of Iran. Optimization results indicate that energy savings by employing DEA and MOGA are 21.15% and 71.63%, respectively. They indicate that the enhancement of the efficiency of paddy production is mainly in terms of toxins and chemical fertilizers. Besides, all adverse environmental impacts by MOGA are significantly less than from its counterparts by DEA and present farms. The most significant difference between MOGA and DEA is associated to ozone layer depletion. As a result, MOGA can be introduced as an adequate optimization method to determine the best mix of paddy production inputs, minimizing adverse environmental impact and maximizing performances of farms and energy efficiency simultaneously. This study highlights the utilization and the performance of MOGA in paddy production systems to determine the optimized composition for mixing energy, yield and environmental impacts. The implementation of the recommended consumption patterns will be able to attain sustainable development in paddy production in Guilan province of Iran, owing to the protection of non-renewable resources, the reduction of adverse environmental effects and the improvement of economic conditions for rice farmers.

Morphological changes on Sagar Island are occurring at an alarming rate due to both natural and anthropogenic activities. The eastern part of the island is rapidly eroding due to destabilization and growth of tidal flats in the Muriganga estuary and the gradual shifting of water current towards the island. Over the last four years (1996)(1997)(1998)(1999), the rate of coastal erosion has been much higher (11.35 km 2 ) than accretion (2.65 km 2 ), compared with the conditions prior to 1996. Coastal places like Dublat, Basantpur, Gobindapur, Collectorganj, and Sumatinagar have become the critical zones of erosion. The shorelines along the eastern and south-western sides are receding. The extent of coverage of the paddy field, sandy beaches, and land vegetation has decreased from 1996 to 1999 by 15.7, 1.1, and 3.5 km 2 , respectively. An integrated database of the island was generated using spatial and non-spatial data collected through field survey, satellite images of IRS-1C LISS III, and topomaps. Spatial data include coastal geomorphological landforms, land-use and land cover, shoreline change, sandy beaches, coastal erosion sites, agricultural fields, aquaculture sites, and coastal riparian vegetations. Non-spatial data include the demography and evolution of the island. The main critical environmental issues of the island are: (1) degradation of mangrove forests and coastal erosion; (2) overpopulation and over-exploitation of living resources; and (3) destruction of seawalls. Further degradation may lead to extinction of a variety of species and scarcity of marine food unless properly managed and regulated.

A six-year field study was conducted to evaluate water management practices of level-terraced paddy fields draining by surface drainage pipe. Field monitoring was conducted to measure rainfall, irrigation, and drainage. Field data revealed that rain water was not efficiently used in some cases. The runoff curve number (CN) was estimated from measured rainfall and runoff data to quantify runoff potential of paddy fields managed by surface drainage pipes. The CN values were determined from the maximum retention storage values at probabilities of 10, 50, and 90%, from a fitted lognormal distribution. The CN values at the antecedent moisture condition (AMC) I, II, and III were found to be 69, 86, and 95, respectively. CN values implied that runoff potential of paddy field managed by drainage pipes would be higher than those of paddy fields using weir type drainage outlets. Appropriate drainage facilities should be introduced for water management and saving labor.

Il volume racconta gli uccelli delle risaie veronesi, l'importanza dell'acqua e delle risorgive, le possibilità di birdwatching tra le vasche allagate o meno, suggerisce un itinerario ornitologico. Tutte le specie note per le risaie sono elencate in una dettagliata check-list, ricordando le specie più rare, mentre una sessantina delle più comuni sono illustrate nel dettaglio in 51 diverse schede, dove per ognuna si ricorda l'abbondanza, la frequenza e le abitudini in Italia e soprattutto nel Veronese e in queste risaie, indicando i nomi dialettali (e il loro perché) e quando è più facile incontrarla.

A 12-month field study was conducted between April 2004 and March 2005 to determine the association between irrigated rice cultivation and malaria transmission in Mwea, Kenya. Adult mosquitoes were collected indoors twice per month in three villages representing non-irrigated, planned, and unplanned rice agro-ecosystems and screened for blood meal sources and Plasmodium falciparum circumsporozoite proteins. Anopheles arabiensis Patton and An. funestus Giles comprised 98.0% and 1.9%, respectively, of the 39,609 female anophelines collected. Other species including An. pharoensis Theobald, An. maculipalpis Giles, An. pretoriensis Theobald, An. coustani Laveran, and An. rufipes Gough comprised the remaining 0.1%. The density of An. arabiensis was highest in the planned rice village and lowest in the non-irrigated village and that of An. funestus was significantly higher in the non-irrigated village than in irrigated ones. The human blood index (HBI) for An. arabiensis was significantly higher in the non-irrigated village compared with irrigated villages. For An. funestus, the HBI for each village differed significantly from the others, being highest in the non-irrigated village and lowest in the planned rice village. The sporozoite rate and annual entomologic inoculation rate (EIR) for An. arabiensis was 1.1% and 3.0 infective bites per person, respectively with no significant difference among villages. Sporozoite positive An. funestus were detected only in planned rice and non-irrigated villages. Overall, 3.0% of An. funestus samples tested positive for Plasmodium falciparum sporozoites. The annual EIR of 2.21 for this species in the non-irrigated village was significantly higher than 0.08 for the planned rice village. We conclude that at least in Mwea Kenya, irrigated rice cultivation may reduce the risk of malaria transmission by An. funestus but has no effect on malaria transmission by An. arabiensis. The zoophilic tendency of malaria vectors in irrigated areas accounts partly for low malaria transmission rates despite the presence of higher vector densities, highlighting the potential of zooprophylaxis in malaria control.

A study was undertaken to determine the freeliving culturable diazotrophic bacteria of paddy soils from a long-term fertilizer management experiment. Long-term application of different fertilizers significantly affected the population of free-living diazotrophs. Out of 165 distinct bacterial morphotypes observed during the isolation process, only 32 were positive for both acetylene reduction assay (ARA), and nifH gene screening. The ARA activity of the isolates ranged from 1.8 to 2,844.7 nmol ethylene h −1 mg protein −1 . The 16S rRNA analysis identified the isolates to be members of 13 different genera viz. Bacillus, Pseudomonas, Paenibacillus, Serratia, Ochrobactrum, Lysinibacillus, Burkholderia, Brevundimonas, Herbaspirillum, Novosphingobium, Sphingomonas, Xanthomonas, and Azorhizobium. Though partial nifH gene sequencing of diazotrophic isolates showed good consistency with that of 16S rRNA-based identification, some nifH sequences were similar to a variety of uncultured nitrogen-fixing bacteria. The diversity of free-living diazotrophic bacteria and the wide distribution of nifH sequences indicate the potential contribution of these microorganisms to nitrogen input to paddy fields.

40 soil samples were collected from 13 cotton, 12 paddy, 3 coconut, 2 tomato and forest and each one from groundnut, coriander, jack fruit, zee mays, potato, blackgram and castor fields. The number of fungal isolate population was highest (1.8×107) and lowest (1.6×107) in the samples 11 (S11) and 15 (S18), which were collected from the coriander and paddy fields in Pavoorchathiram, Tirunelveli district and Sathoor, Virudunagar districts, respectively. Among the 40 samples collected from different areas, 21 samples consisted of Metarhizium anisopliae (Metsch.) Sorokin. Minimum M. anisopliae colonies (21 colonies) were recorded from the cotton field soil sample (S14) of Vilupuram District. But the highest fungal population (4.8×104) among cotton fields was also recorded from the samples of Thoothukudy district. M. anisopliae strain could not be isolated from the soil samples collected in Trichy, Madurai, Virudunagar, Kanchipuram, Tiruvallur, Dharmapuri, Salem, Namakkal, Chennai, Cuddalore, Pondicherry, Sivagangai, Dindhugal, Ramanathapuram and Karur Districts. The impact of all the 21 M. anisopliae isolates and also the standard MTCC892 were tested against Dysdercus cingulatus (Fab.) (Hemiptera: Pyrrhocoridae) adults and the LC50 values ranged from 2.25×105 to 3.66×108 spores/ml. The lowest (2.25×105) and the highest (3.66×108) LC50 values were recorded for the isolates CPRC16, and CPRC17, respectively. 11 sporulated D. cingulatus cadavers were observed with the isolate CPRC18.

Recently, agriculture production systems have benefited from incorporation of technological advances primarily developed for other industries. Site-specific crop management, well-established in some developed countries, is now being considered in other places such as Malaysia. The application of site-specific management principles and techniques to diverse crops and small-scale farming systems in Malaysia will present new challenges. Describing within-field variability in typical Malaysian production settings is a fundamental first step toward determining the size of management zones and the interrelationships between limiting factors, for establishment of site-specific management strategies. Measurements of rice (Oryza Sativa L.) SPAD readings was obtained in a Malaysian rice paddy field those were manually collected on 2 different rice growth stages (55 DAT and 80 DAT) and measured using a Minolta SPAD 502. Analysis of variance, variogram and kriging were conducted to determine the variability of the measured parameter. Finally, SPAD reading maps were created on the interpretation of the data was investigated.

A B S T R A C T The spatial and temporal patterns of CO 2 and CH 4 fluxes in China's croplands were investigated and attributed to multifactor environmental changes using the agricultural module of the Dynamic Land Ecosystem Model (DLEM), a highly integrated process-based ecosystem model. During 1980-2005 modelled results indicated that China's croplands acted as a carbon sink with an average carbon sequestration rate of 33.4 TgC yr −1 (1 Tg = 10 12 g). Both the highest net CO 2 uptake rate and the largest CH 4 emission rate were found in southeast region of China's croplands. Of primary influences were land-cover and land-use change, atmospheric CO 2 and nitrogen deposition, which accounted for 76%, 42% and 17% of the total carbon sequestration in China's croplands during the study period, respectively. The total carbon losses due to elevated ozone and climate variability/change were equivalent to 27% and 9% of the total carbon sequestration, respectively. Our further analysis indicated that nitrogen fertilizer application accounted for 60% of total national carbon uptake in cropland, whereas changes in paddy field areas mainly determined the variability of CH 4 emissions. Our results suggest that improving air quality by means such as reducing ozone concentration and optimizing agronomic practices can enhance carbon sequestration capacity of China's croplands.

Nitrogen balance in a paddy field planted with whole crop rice (Oryza sativa cv. Kusahonami) during two rice-growing seasons Abstract This paper focuses on N balance in a paddy field planted with whole crop rice (Oryza sativa cv. Kusahonami). The experiment was conducted with two treatments during two rice-growing seasons: one was fertilized with N (160 kg N ha −1 ; 16N plot) and the other unfertilized (0N plot); both plots were fertilized with P and K. The N input from precipitation was 15 and 12 kg N ha −1 in 2002 and 2003, respectively. The N input from irrigation water reached as much as 123 and 69 kg N ha −1 in 2002 and 2003, respectively. This was because irrigation water contained higher NO 3 − concentrations ranging from 4 to 8 mg N l −1 . The N uptake by rice plants was the major output: 118 and 240 kg N ha −1 in the 0N and 16N plots in 2002 and 103 and 238 kg N ha −1 in 2003, respectively. N losses by leaching were 4.8-5.3 and 6.5-7.3 kg N ha −1 in 2002 and in 2003, respectively.

The Sundarban, covering about one million ha in the delta of the rivers Ganga, Brahmaputra and Meghna is shared between Bangladesh (~60%) and India (~40%), and is the world’s largest coastal wetland. The area experiences a subtropical monsoonal climate with an annual rainfall of 1,600–1,800 mm and severe cyclonic storms. Enormous amounts of sediments carried by the rivers contribute to its expansion and dynamics. Salinity gradients change over a wide range of spatial and temporal scales. The biodiversity includes about 350 species of vascular plants, 250 fishes and 300 birds, besides numerous species of phytoplankton, fungi, bacteria, zooplankton, benthic invertebrates, molluscs, reptiles, amphibians and mammals. Species composition and community structure vary east to west, and along the hydrological and salinity gradients. Sundarban is the habitat of many rare and endangered animals (Batagur baska, Pelochelys bibroni, Chelonia mydas), especially the Royal Bengal tiger (Panthera tigris). Javan rhino, wild buffalo, hog deer, and barking deer are now extinct from the area. Large areas of the Sundarban mangroves have been converted into paddy fields over the past two centuries, and more recently into shrimp farms. The Sundarban has been extensively exploited for timber, fish, prawns and fodder. The regulation of river flows by a series of dams, barrages and embankments for diverting water upstream for various human needs and for flood control has caused large reduction in freshwater inflow and seriously affected the biodiversity because of an increase in salinity and changes in sedimentation. Heritiera fomes (locally called Sundari, from which Sundarban derives its name), Nypa fruticans and Phoenix paludosa are declining rapidly. During the past three decades, large parts of the remaining Sundarban have been protected for wildlife, particularly tiger, through the creation of several sanctuaries and a biosphere reserve. Parts of the Sundarban in both India and Bangladesh have been declared World Heritage sites. However, its biodiversity continues to be threatened by a growing human population that not only places pressure on its biological resources, but also impacts on the freshwater inflows from upstream areas. Oil exploration in coastal areas is also emerging as a new threat. Further threats arise from global climate change, especially sea level rise. The future of the Sundarban will depend upon the management of freshwater resources as much as on the conservation of its biological resources.

Site-specific crop management, well-established in some developed countries, is now being considered in developing countries such as Malaysia. The apparent electrical conductivity (ECa) of the soil can be used as an indirect indicator of a number of soil physical properties and even crop yield. Commercially available ECa sensors can efficiently develop the spatially dense data sets desirable in describing within-field spatial soil variability for precision farming. The main purpose of this study was to generate a variability map of soil ECa within a Malaysian paddy field using a VerisEC sensor. The ECa values were then compared with some soil variables within classes after delineation. Measured parameters were mapped using the kriging technique and their correlation with soil ECa was determined. The study showed that the VerisEC can determine soil spatial variability, and can acquire soil ECa information quickly. Spatial variability of shallow and deep ECa showed the same patterns. Estimation of soil properties based on ECa varied from one soil parameter to another and all could be estimated better by deep ECa. Cross-validation results showed that shallow and deep ECa, and also bulk density, gave more accurate estimates compared with other variables.

Following the national policy, the Department of Agriculture of Thailand has implemented a crop diversification program in several provinces of the country. This study, which was conducted in Nakhon Pathom Province, analyzed the extent of crop diversification and its determinants using primary information collected from 245 farm households using a structured questionnaire, and from selected farmer leaders and agricultural development officials. The study also assessed the effects of crop diversification on income and the inputs used. The findings of the study revealed that nearly three fourths of the land is still being used for rice mono-cropping, indicating little success in the promotion of the crop diversification program. Paddy fields, including farms for cultivating rice under mono-cropping and diversified system, still account for 90% of the total farmland in the country. The limited impact of the program on the farming sector is attributed primarily to the variation in land and labor resources available at the farmers' disposal as well as soil suitability. The farmers' attendance in training and interaction with farmer groups are the other influential factors. Although cropping diversification has provided attractive financial return particularly to the small farmers, it has also accelerated the use of inorganic fertilizers and pesticides. Broad policy instruments are therefore suggested for the effective implementation of future crop diversification programs in Thailand and perhaps elsewhere in Southeast Asia.

Microalgae were isolated during a screening program from soil samples collected from paddy-fields of Fars province, south of Iran. The protein content was assayed by the Kochert method. Total genomic DNA were isolated and used for PCR amplification of the 18S rRNA gene. The sequences were determined for 12 species of microalgae. Some bioinformatic tools were used for more investigation on these biologic data. Total lipids from five microalgal species were extracted and used for determination of different types of fatty acids by gas chromatography-mass spectrometry method. In our experiments the green algae yielded a maximum protein of about 42% ± 1.64. The DNA sequences were published in the NCBI under specific accession numbers. The composition of fatty acids was mainly, myristic acid, palmitic acid, oleic acid, a-linolenic acid, and c-linolenic acid.

The biodiesel production from a naturally isolated strain of Chlorella in 2 L bubble-column photobioreactor was studied. The microalgal strain was isolated from the rice paddy-field soil samples during a screening program. After 17 days, at the end of exponential phase of growth, the total content of the lipids was extracted. The extracted fatty acids were first esterified and then identified using GC/MS analysis. Several types of fatty acid methyl esters (FAMEs) were identified in the isolated microalga and the presence of saturated fatty acids in Chlorella sp. MCCS 040 was approved. The composition of fatty acids in the studied species of microalga was mainly palmitic acid methyl ester, myristic acid methyl ester, stearic acid methyl ester and undecanoic acid methyl ester. This strain because of its highly saturated fatty acids content can be an ideal candidate for biodiesel production.

Introduction of irrigation projects in developing nations has often been blamed for aggravating the problem of mosquito-borne diseases by creating ideal larval habitats for vector mosquitoes. However, whereas several studies have demonstrated the relationship between malaria vectors and irrigation, little work has been done on culicine mosquitoes despite their potential in transmission of filariasis and arboviruses and their significant biting nuisance in these areas. This study examined the diversity of Culex mosquito fauna and their larval habitats at two sites (Murinduko and Kiamachiri) in Mwea, Kenya over a 12-month period. The habitat types present at each site within a 200-meter radius around the study village, including randomly selected paddies and canals, were sampled every two weeks to examine the relationship between vegetation cover, water depth, turbidity, and Culex larval counts. Ten culicine species belonging to four genera were identified, with 73.1% of the total col...