Deep Flooding Research Articles

Rice-crayfish integrated system enhances global warming potential via increasing methane emission mainly driven by continuous deep flooding

The conversion from rice monoculture (RM) to rice-crayfish integrated system (RCIS) could change soil physicochemical properties and microorganisms related to greenhouse gas (GHG) emissions. Nevertheless, it is still unclear the responses of GHG emissions and global warming potential (GWP) from paddy fields to RCIS. Here, we conducted a field experiment to investigate the changes in the emissions of methane (CH4) and nitrous oxide (N2O), GWP, soil physicochemical properties and the associated microbial abundances (methanogen, methanotrophs, denitrifier and nitrifier) under RCIS in Gaoyou City, Jiangsu Province, China from 2022 to 2023. There were three treatments, including RM, rice monoculture with continuous deep flooding (RMF) and RCIS. Compared with RM, RCIS and RMF all significantly increased CH4 emission and decreased N2O emission. But the effectiveness of increasing CH4 emission and decreasing N2O emission was larger under RCIS than RMF. The increased CH4 emission was due to the significantly higher mcrA gene abundance and ratio of mcrA/pmoA under RCIS. While the significantly higher nosZ gene abundance and ratio of nosZ/(amoA+nirK+nirS) under RCIS were responsible for its reduced N2O emission. Furthermore, the increases in gene abundances of mcrA and nosZ under RCIS were closely correlated with the significantly lower redox potential and pH as well as the significantly higher contents of dissolved organic carbon, ammonium and nitrate in soil. Averaged across two years, GWP under RCIS and RMF were 4.6-fold and 3.4-fold that under RM, respectively. This revealed that continuous deep flooding had a greater effectiveness in increasing GWP than crayfish culture under RCIS. Notably, the contribution rates of CH4 emission to the total GWP decreased in the order of RCIS (98.6%) > RMF (97.5%) > RM (86.2%). Besides, greenhouse gas intensity under RCIS was 5.1-fold that of RM due to its enhanced GWP and reduced rice grain yield. In summary, RCIS could enhance GWP from paddy fields through increasing CH4 emission mainly caused by the continuous deep flooding.

Compilation method of a catalogue of reasonable worst-case rainfall series for flash flood simulations of short, convective rainstorms

In this study, a categorisation method was developed and applied to identify, select and rank reasonable worst-case rainfall storm events with time-series resolution of one minute and duration of up to one hour. The method yields a catalogue of 24 reasonable worst-case rainfall series, i.e. potentially catastrophic events that could be used for safe-to-fail flash flood model scenarios, thus encouraging the testing of critical infrastructure and pedestrian safety for people trapped in floods. The identified 24 events were shown to be considerably more extreme than corresponding design storms, with a return interval of 100 years. In the selection of the extremes, special care was taken to consider different hazard attributes, which are associated with intrinsically different observed hyetograph shapes, including rectangular, short and long triangle, and double peak shape categories. Hydrodynamic simulations were carried out using the 2D robust shallow water model hms++ to quantify the flooding impact of the 24 rainfall scenarios in a small urbanised catchment, which enabled the ranking of the scenarios based on different hazard attributes. Overall, the rectangular and long-triangle events showed the highest total discharge, and the rectangular events comprise both the longest duration for hazard velocity and deep flooding. The long-triangle events presented the highest peak discharge and peak water depths. The short-triangle ones showed the highest flashiness (shortest time to peak), whereas the double peak events yielded the longest time to peak. The ranking emphasised the importance of the hyetograph shape characteristics of extreme storms and which needs to be taken into account in flash flood management. The novel categorisation method is easily transferable to other regions, if high-resolution rain series are available.

Water depth-dependent stem elongation of completely submerged Alternanthera philoxeroides is mediated by intra-internodal growth variations.

Complete submergence, especially deep submergence, poses a serious threat to the growth and survival of plants. One study previously showed that Alternanthera philoxeroides (a herbaceous perennial plant) submerged at depth of 2m presented fast stem elongation and reduced stem elongation as water depth increased. In the present study, we aimed to figure out from the morphological and anatomical perspective how the differential growth response of the plant to water depth was achieved. We investigated the elongation of different stem parts and the relationship of stem elongation to cell size and number in A. philoxeroides by conducting experiments using a series of submergence depths (0m, 2m, 5m, and 9m). The results showed that, in comparison with unsubmerged plants, completely submerged plants exhibited enhanced elongation at depths of 2m and 5m but suppressed elongation at depth of 9m in immature stem internodes, and displayed very little elongation in mature stem internodes at any depths. The stem growth of A. philoxeroides at any submergence depth was chiefly caused by the elongation of the basal parts of immature internodes. The elongation of the basal parts of immature internodes was highly correlated to both cell proliferation and cell enlargement, but the elongation of the middle and upper parts of immature internodes correlated nearly only with cell enlargement. This study provided new information on the growth responses of A. philoxeroides to heterogeneous submergence environments and deepened our understanding of the growth performance of terrestrial plants in habitats prone to deep floods.

Creation of Rice Doubled Haploids Resistant to Prolonged Flooding Using Anther Culture.

Flood resistance in rice is very important in weed control, as weeds cannot overcome deep water. At present, there are no released varieties in Russia that would meet these requirements. The creation of such varieties will reduce production costs and pesticide load on the ecosystem. The object of the study was second-generation rice hybrids obtained by crossing the best varieties for economically valuable traits with samples carrying genes for resistance to prolonged flooding with water. To create double rice haploids resistant to prolonged flooding, the anther culture method was used, followed by molecular genetic evaluation of dihaploids for the presence of genes for resistance to prolonged flooding. An estimate of the growth energy under deep flooding was carried out according to our own method. As a result of the cultivation of anthers, 130 androgenic regenerated plants were obtained in 14 hybrid combinations. In terms of responsiveness to neoplasms, 60% of the panicles showed a positive result, while the rest 40% did not demonstrate callus formation. In total, 30 green regenerative lines were obtained from four rice hybrids, differing in visual morphological assessment. Large genotypic differences between the samples were revealed. These lines carry long-term flood resistance genes and can be used in rice breeding programs using dihaploids. As a result of the assessment of the growth energy in a number of obtained samples, the potential for rapid elongation of the first leaves, overcoming a large layer of water and accumulation of vegetative mass, was revealed.

Risk assessment of individuals exposed to urban floods

Risk assessment of individuals in urban flooding events requires quantitative criteria of human instabilities and hazard identifications. The existing guidelines might not be representative of some inundation situations in urban settings without considering the risks associated with human behaviors. Current guidelines may be under or over-estimated to be applied during a natural urban flooding disaster. This work proposes a hybrid model by coupling an efficient hydrodynamic model with a physics-based model to quantify individuals’ instabilities in urban flood events, both children and adults, based on the flow regimes and human physical characteristics. The model accounts for human behavior and the failure mechanism caused by physical instabilities of toppling, sliding, and drowning. The hazard degree is identified in terms of flow velocity and water depth in floodwaters. The hydrodynamic model is calibrated in a densely urbanized area in the city of the UK and the instabilities threshold curves for adults and children are validated using existing measurements in the literature. Applications of extreme precipitation events that occurred in Wuhan city of China showed that adults are relatively safe in most of the study sites with a low hazard except in the areas where the flood water depth exceeds the low limit of hazard criteria. However, the distribution of flood hazard degrees for children is significantly increased compared to that for adults. Furthermore, hazardous zones were observed in the vicinity of critical facilities such as the government house, supermarket, hospital, metro station, and primary school, consistent with the deep flood depth distribution. Overall, this work develops a hybrid model for risk assessment of individuals exposed to urban floods and the hazard criteria that could be implemented in urban flood risk management for sustainable cities.

Seed biology of alkali barnyardgrass (Echinochloa crus-galli var. zelayensis) and junglerice (Echinochloa colona) for improved management in direct-seeded rice

AbstractAlkali barnyardgrass [Echinochloa crus-galli var. zelayensis (Kunth) Hitchc] and junglerice [Echinochloa colona (L.) Link] are problematic annual weeds in direct-seeded rice (Oryza sativa L.) fields in China. The emergence ecology of the two weed species may differ in response to environmental factors. Laboratory and screenhouse experiments were conducted to evaluate the effects of light, burial depth, mulching with wheat (Triticum aestivum L.) residue, and time and depth of flooding on the emergence of the two weed species collected from Nanjing, China. Light strongly increased seed germination. Under dark conditions, E. crus-galli seed germination (85%) was higher than that of E. colona (70%). The seeds of both species exhibited the greatest germination (90% for E. crus-galli and 80% for E. colona) when sown on the soil surface, and emergence decreased with increasing soil burial depth. Burial depths of 2.2 and 1.4 cm reduced seedling emergence by 50% for E. crus-galli and E. colona, respectively. No emergence was found at a depth of 6 cm. The seedling emergence for E. colona was lower than for E. crus-galli at the same soil burial depth. Mulching with wheat residue considerably reduced the seedling emergence and aboveground biomass of both species. The inhibitory effect of mulching with wheat residue on E. colona was more notable than on E. crus-galli. Early and deep flooding significantly suppressed the emergence, height, and biomass of E. crus-galli and E. colona, especially E. colona. The results gained from this study could provide fundamental ecological knowledge for managing Echinochloa species in direct-seeded rice systems.

Hydrodynamic Modeling of Inundation Patterns of a Large African Floodplain Indicates Sensitivity to Waterway Restoration

AbstractLarge‐scale floodplains are important features of the African continent. Regular inundation provides the means to support large populations but can also present problems such as access to health facilities and water body formation that sustain malaria vectors. Modeling of these floodplains is therefore important, but complex. In this research, we develop, calibrate, and validate a hydrodynamic model of the Barotse Floodplain, of the Upper Zambezi, Zambia. The floodplain has seen recent infrastructure developments including the restoration of the canal network and construction of a cross floodplain causeway. In order to create a robust model, a multiobjective calibration uses a time slice approach based on available Landsat satellite image overpasses. An emulator‐based sensitivity analysis indicates the significance of hydrological processes in the model. Model evaluation is undertaken for two events in the gauge record (2009 and 2018), of similar magnitude that occur before and after modifications to the floodplain. Results indicate a complex impact of infrastructure development on the hydrodynamics of the floodplain, with a higher peak flow, but with a redistribution of water throughout the floodplain. Deeper flooding is observed in some areas while others experience lower water levels. The sensitivity results also reflect a change in processes, where floodplain flows dominate the 2009 event, whilst channel process dominate the 2018 event. Overall, we show that relatively modest modifications to the floodplain have impacted flood water levels, which in turn will influence access route availability and alter malaria transmission rates.

Impact of waterlogging and heat stress on rice rhizosphere microbiome assembly and potential function in carbon and nitrogen transformation

ABSTRACT The impacts of rhizosphere microorganisms on the turnover of nutrients are affected by many environmental factors. In this study, rice plants were subjected to deep flooding and heat stress for one week at the jointing stage. Rhizospheric soil was sampled for the analysis of rice rhizosphere bacterial assembly and functional groups responsible for carbon and nitrogen transformation. Compared with the control, both deep flooding and heat stress increased bacterial alpha diversity. Moreover, heat stress and the interactions of heat stress and deep flooding improved the bacterial cooperation. Heat stress reduced the relative abundance of Actinobacteria and Firmicutes, which are responsible for organic carbon decomposition. The relative abundance of the gene encoding lignin-degrading catalases under deep flooding and heat stress treatments reduced by 6% and 8%, respectively. The interaction of heat stress and deep flooding increased the relative abundance of the nifD gene by 5%, may slowed down nitrate reduction to nitrite. Our results highlight the effects of heat and flooding stress on the bacteria-mediated mechanisms responsible for regulating organic carbon sequestration and nitrogen cycling in rhizosphere of paddy fields.

3D Inundation Mapping: A Comparison Between Deep Learning Image Classification and Geomorphic Flood Index Approaches

Inundation mapping is a critical task for damage assessment, emergency management, and prioritizing relief efforts during a flooding event. Remote sensing has been an effective tool for interpreting and analyzing water bodies and detecting floods over the past decades. In recent years, deep learning algorithms such as convolutional neural networks (CNNs) have demonstrated promising performance for remote sensing image classification for many applications, including inundation mapping. Unlike conventional algorithms, deep learning can learn features automatically from large datasets. This research aims to compare and investigate the performance of two state-of-the-art methods for 3D inundation mapping: a deep learning-based image analysis and a Geomorphic Flood Index (GFI). The first method, deep learning image analysis involves three steps: 1) image classification to delineate flood boundaries, 2) integrate the flood boundaries and topography data to create a three-dimensional (3D) water surface, and 3) compare the 3D water surface with pre-flood topography to estimate floodwater depth. The second method, i.e., GFI, involves three phases: 1) calculate a river basin morphological information, such as river height (hr) and elevation difference (H), 2) calibrate and measure GFI to delineate flood boundaries, and 3) calculate the coefficient parameter (α), and correct the value of hr to estimate inundation depth. The methods were implemented to generate 3D inundation maps over Princeville, North Carolina, United States during hurricane Matthew in 2016. The deep learning method demonstrated better performance with a root mean square error (RMSE) of 0.26 m for water depth. It also achieved about 98% in delineating the flood boundaries using UAV imagery. This approach is efficient in extracting and creating a 3D flood extent map at a different scale to support emergency response and recovery activities during a flood event.

Interpreting landscapes of pre-Columbian raised-field agriculture using high-resolution LiDAR topography

Extensive areas of seasonally flooded savannas in South America are covered with vestiges of pre-Columbian raised fields. The present-day state of these vestiges depends on both initial human agency and the balance between erosion and accumulation by soil organisms. We investigated the taphonomic determinants of mound-shaped raised fields in the Llanos de Mojos, Bolivia, using high-resolution digital terrain models produced by LiDAR mounted on an unmanned aerial vehicle, allowing fine-scale characterization of topographic gradients and of shapes of hundreds of mounds. We found that pre-Columbian farmers built larger and more widely spaced mounds at lower elevation, where seasonal flood level is higher. However, mound size depended also on natural forces that are still in play. As for earthworks everywhere, these forces include the landscape-smoothing process of erosion. But in seasonally flooded savannas, positive feedbacks between topography and activities of soil engineer organisms can drive accumulation of material on mounds. The erosion/accumulation balance hypothesis posits that the balance between erosion and accumulation depends on whether conditions favor local accumulation of soil by engineer organisms. These conditions vary along elevational gradients. At the lowest end of the gradient, deep flooding prevents activity of soil engineers and erosion is unopposed. In intermediate positions, where mounds constitute islands of well-drained soil, soil engineers concentrate their activities on mounds, leading to accumulation that may counter erosion. At the top of the gradient, where all soil is well-drained, conditions for soil engineers are favorable everywhere, and thus no force drives local accumulation in mounds. Erosion is thus again unopposed. Patterns of variation in mound size and shape revealed by analysis of LiDAR imagery were consistent with the erosion/accumulation balance hypothesis. Mounds were largest at intermediate positions along topographic gradients and smaller towards both extremes, until they finally became undetectable. Relative height of mounds (maximal height/ radius at base) decreased as mound size decreased, consistent with the expectation that as mounds erode, they also become flatter. Finally, trees occurred preferentially on mounds, and mounds bearing a tree were less eroded (higher and less flat) than mounds without trees. Data generated by LiDAR thus contributed to archaeological interpretation, supporting inferences about how raised fields were initially constructed and how natural processes have modified their size, shape, and distribution in the centuries since.

Trapped between drowning and desiccation: Riverine plants under hydropeaking

Hydropeaking is part of hydropower production. The discontinuous release of turbined water during hydropeaking generates sudden rise and falls of the water levels, as well as extended droughts. These artificial flow fluctuations impose challenging growing conditions for riverine vegetation. In order to identify vulnerable/resistant plant species to hydropeaking and to evaluate the impact of contrasting hydropeaking scenarios (simplified (i.e., sudden deep floods, frequent soil saturation and drought) and real-life, power plant-induced scenarios), we measured germination, survival, and morphological and physiological attributes of a selection of 14 plant species commonly found along riparian areas. Species were subject to different hydropeaking scenarios during three months (vegetative period) in the field and in a greenhouse. Half of the species performed worse under hydropeaking in comparison to the control (e.g., less germination and biomass, lower growth rates, reduced stem and root length, physiological stress) but none of the tested hydropeaking scenarios was clearly more disruptive than others. Betula pubescens, Alnus incana and Filipendula ulmifolia showed the largest vulnerability to hydropeaking, while other species (e.g., Carex acuta) were resistant to it. Both in the field and in the greenhouse, plants in perturbed scenarios accumulated more 13C than in the control scenario indicating limited capacity to perform 13C isotope discrimination and evidencing plant physiological stress. The highest 13C abundances were found under drought or flooding conditions in the greenhouse, and under the highest hydropeaking intensities in the field (e.g., Betula pubescens). Our results suggest that any hydropeaking scheme can be equally detrimental in terms of plant performance. Hydropeaking schemes that combine periods of severe drought with long and frequent flooding episodes may create a hostile environment for riverine species. Further research on “hydropeaking-tolerant” plant traits is key to draw the boundaries beyond which riverine species can germinate, grow and complete their life cycle under hydropeaking.

Adaptability Analysis of Deep Profile Control and Flooding Formula System in Water Injection Oilfield

Adaptability Analysis of Deep Profile Control and Flooding Formula System in Water Injection Oilfield

Effects of Hydrological Regime on Foliar Decomposition and Nutrient Release in the Riparian Zone of the Three Gorges Reservoir, China.

Foliar decomposition has significant effects on nutrient cycling and the productivity of riparian ecosystems, but studies on the impact of related hydrological dynamics have been lacking. Here, the litterbag method was carried out to compare decomposition and nutrient release characteristics in situ, including three foliage types [two single-species treatments using Taxodium distichum (L.) Rich., Salix matsudana Koidz., or a mixture with equal proportions of leaf mass], three flooding depths (unflooded, shallow flooding, and deep flooding), two hydrodynamic processes (continuous flooding and flooded-to-unflooded hydrological processes), and one hydrological cycle (1 year) in the riparian zone of the Three Gorges Reservoir. The results showed that both hydrological processes significantly promoted foliage decomposition, and all foliage types decomposed the fastest in a shallow flooding environment (P < 0.05). The mixed-species samples decomposed most quickly in the flooded hydrological process in the first half of the year and the unflooded hydrological process in the second half of the year. Flooding also significantly promoted the release of nutrients (P < 0.05). Mixed-species samples had the fastest release rates of carbon and nutrients in the flooded hydrological process in the first half of the year and the unflooded hydrological process in the second half of the year. Foliage decomposition was also closely related to environmental factors, such as water depth, temperature, and hydrological processes. Our research clarified the material cycling and energy flow process of the riparian ecosystem in the Three Gorges Reservoir area. It also provided a new reference for further understanding of foliage decomposition and nutrient release under different hydrological environments.

Hydraulic and morphological patterns in a riparian vegetated sandy compound straight channel

Emergent vegetation or trees are important riverine features and essential in hydraulic engineering including flood management and river restoration. Clearing up trees along river banks has been pointed out as a contributing factor to the severity of flood damages including financial losses and even fatalities. Thus, the effect of riparian vegetation on river flow must be clearly understood. The hydraulics and morphological patterns in a riparian vegetated sandy compound straight channel were carried out in the Hydraulics Laboratory, School of Civil Engineering, Universiti Teknologi Malaysia. Two-line steel rods with tandem and staggered arrays to simulate as rigid emergent vegetation were placed along the riparian zone of an asymmetrical straight channel. The Manning’s n, depth-averaged velocity, boundary shear stress and morphological changes during shallow and deep floods are discussed in this paper. The findings prevailed that the staggered array riparian vegetation generated 4.5% flow resistance higher than the tandem array. The vegetation also altered velocity distribution which contributed to the boundary shear stress patterns in a compound straight channel. The flow velocity profiles were also related to the morphological changes in the channel.

Comparative Analysis of Economic Effects of Soft Microgel Flooding and Polymer Flooding

Soft microgel is discontinuous phase. Profile control and flooding technique of soft microgel, deferent from polymer flooding, is a technical method of secondary development of old oil fields. In this paper, we further enrich the flooding mechanism of soft microgel and propose the mechanism of targeting of oil displacement on the basis of synchronous flooding. Profile control and flooding technique of soft microgel has been applied in many oil fields at home and abroad and achieved significant effect of reducing water production and increasing oil. For evaluating the technical and economic effects, firstly, we summarize and analyse the field test results of SMG flooding technology in five oilfield blocks including Huabei oilfield, Changqing oilfield and son on. What’s more, the field data of polymer flooding is investigated by consulting scientific papers. At last we compare and analyse the economic effects of soft microgel and polymer flooding by using EOR value and barrel oil cost as evaluation indexes, According to the incomplete statistical data, the economic effect of soft microgel deep flooding technology is better than that of polymer flooding technology.

Flood Risk and Its Effect on Property Value in Kuala Krai, Kelantan

The effect of flood risk on property value is vital because property is the most asset coveted by people for ownership. The attraction to live in a location induces people to give less priority to environmental threat such as flood. This study investigates whether the value of the properties was affected by flood risk by taking Kuala Krai, Kelantan, as a case study. By combining spatial analysis, Geographic Information System mapping and statistical analysis, this study included flood risk as one of the tested variables to determine whether it has affected property value. The statistical methods used were the Ordinary Least Squares regression model (OLS) and Geographically Weighted Regression (GWR). Market prices of a total of 811 transacted properties in the district of Kuala Krai were used to generate statistical model and property maps. The ArcGIS software was used to display and store modeled flood in the study area. The findings showed that higher property values were found around urban centers such as Kuala Krai, Dabong, and Manik Urai, although these areas were among the areas with deep flood inundation. The study disclosed that despite living in areas exposed to flood, the value of property was unaffected. On the other hand, the strategic location in the population concentration area has made it a more important factor than flood risk in determining the impact on property value. Furthermore, people’s receptiveness, adaptability, and risk-taking attitudes were likely to have caused flood to have failed to dislodge the population from flood-prone areas. Another possibility was that flood-prone areas were important economic activity zones so much so that people were more interested to live and work there rather than responding to flood risk.

Solutions to deal with flooding by using green buildings in Vietnamese urban areas from Japanese experience

One of the major problems of big cities in Vietnam is deep flooding in the rainy season, frequent traffic jams, fewer green areas, green parks are narrowed or exploited for commercial exploitation and services. The above consequences are due to many reasons such as rapid urban development, encroachment of rivers and streams that break the natural landscape, lack of synchronous planning … there is still a lack of reasonable technical solutions. Japan is a country with a lot of experiences in flood prevention, about preserving a safe and close environment to nature. These solutions can be an idea for strategic decision makers, governments and the whole community to refer to Vietnam, especially big cities like Ho Chi Minh City learning and applying. Here are some experiences from Japan analyzed and opened by the author to contribute ideas for our city to become more civilized and worth living.

Hydraulic control on the development of megaflood runup deposits

Runup deposits are veneers of alluvium that drape floodway valley side walls above the height of giant bars deposited during megafloods. Given sufficient sediment supply, the highest giant bars, deposited in re-entrants along the flood margins, tend to grow to close to the maximum time-averaged water level of the flood. However, considerable fluctuations in the water level, caused by sediment-charged floodwaters surging over shorter time-scales, are responsible for the higher runup deposits. Here, the theoretical calculations of the expected maximum runup heights are compared with surveyed heights of six runup deposits in the Chuja Valley, Altai, Siberia. The limitations and strengths of the theoretical approach are identified and modified parameters proposed that can be used to provide partial explanation for the differences between theory and observation. Conceptually, surging can be viewed as caused by four interrelated elements: (1) propagation of undular weir flow; (2) macroturbulence; (3) flow separation; and (4) standing, reflection and interference waves. The heights of the observed runup deposits primarily are related to the depth of the flood water above the bar tops and, to a lesser extent, the Froude number, but tend to lie below the maximum surge heights of the modelled flow. Changes in the effective geometry of the flow re-entrant, mediating flow patterns, as water depth increases is likely the cause of mismatch between theory and observation. Runup deposits may also lie at lower elevations than predicted because of sediment supply considerations and the return flow of surges ‘combing’ down deposits. Nonetheless, the difference between observed and predicted runup heights is often only a few tens of metres such that, for deep floods, runup deposits potentially are useful palaeostage indicators. The analysis also indicates that upper-stage plane beds do not dominate bar tops, rather bar top deposition was primarily to lower-stage plane beds, from dense suspensions.

Combining deep flooding and slow-release urea to reduce ammonia emission from rice fields

Abstract The high risk of ammonia (NH3) emission from rice fields limits the efficient and cleaner production of rice (Oryza sativa L.). Currently, little is known about the combined effects of irrigation and fertilization on NH3 emission from rice fields. Specially, the contributions of different field factors to NH3 emission and the role of the rice canopy in NH3 emission are not fully understood. This study aimed to (i) determine the best combination of irrigation and fertilization for reducing NH3 emission from rice fields and (ii) elucidate the mechanisms involved based on the data from 17 field factors. A 2-year field experiment (2017 and 2018) was performed consisting of nine treatments: the full combination of three irrigation treatments (deep flooding (DF), moderate flooding (MF), and shallow flooding (SF)) and three fertilization treatments (the control test (N0), urea (U), and slow-release urea (SU)). The results indicated that nitrogen (N) application significantly increased NH3 emission from rice fields (p

Yield Response and Water Productivity for Rice Growth With Several Irrigations Treatment in West Java

As the challenges toward increasing water for irrigation and water scarcity threats become more prevalent, knowledge of crop yield response to water can facilitate the development of irrigation strategies for improving agricultural productivity. Experiments were conducted to to compare water usage of several irrigation treatment on rice growth performance and productivity and its water use efficiency. These experiments were conducted using Situbagendit rice variety (115 day length periode), Urea and Tri Super Phospate fertilizer. Fertilizer dosage follows fertilizer recommendations for rice, i.e : Urea 250 kg/ha, SP-36 100 kg/ha and 100 kg KCl/ha. Irrigation started from land preparation. controll block (deep flooding) was flooded by a water height of 7 cm. Low level continues flow block was flooded by a water height of 3-5 cm. The volume of water used to saturate the soil of the saturated block was estimated. The number of days of non-flooded soil in AWD before irrigation is applied can vary from 1 day to more than 5 days. The results showed that total volume of water supplied during the rice growing period in the control block was 2,761.91 m3. Total water volume related to the low level continous flow irrigation block was about 1,217.03 and only about 638.98 m3 for the alternate wet and dry irrigation block. Total volume supplied for soil saturation treatment was about 549.74 m3. Regardless the performance of rice crop growth, it’s the most efficient treatment in terms of water use. It only required an amount of water around14-20 % of amount of water consumed by the continuous deep flooding treatment. The rice yield of deep flooding irrigation treatment was equivalent to 5.6 tons/ha of dry paddy while the yields of low level continuous flow irrigation,alternate wet and dry irrigation and soil saturation treatments reached 5,3 tons/ha,3.36 tons/ha and 2.80 tons/ ha respectively