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1.
A field experiment was performed at two Korean research sites to evaluate water and nutrient behavior in paddy rice culture operations for 2 years. One site was irrigated with groundwater, whereas the other site was irrigated with surface water. Both sites received average annual rainfall of about 1,300 mm, and about 70–80% of it was concentrated during July–September coinciding with rice growing season. Although most of the nutrient outflow was attributed to plant uptake, nutrient loss by surface drainage was substantial. The simplified computer model, PADDIMOD, was developed to simulate water and nutrient behaviors in the paddy rice field. The model predicts daily ponded water depth, surface drainage, and nutrient concentrations. It was formulated with a few equations and simplified assumptions, but its application and a model fitness test indicated that the simulation results reasonably matched the observed data. It is a simple and practical planning model that could be used to evaluate nutrient loading from paddy rice fields alone or in combination with other complex watershed models. Further validation might be required for general application of the PADDIMOD to the simulation of paddy rice fields with various agricultural environments.  相似文献   

2.
Curbing nutrient loads from rice cultivation has been an issue for the water quality management of surface water bodies in the Asian monsoon region. The objectives of this study were to develop paddy BMP scenarios and to evaluate their effectiveness on nutrient loads reduction using long-term model simulation. Totally five BMP scenarios were developed based on the three paddy farming factors of drainage outlet height, fertilizer type, and application amount and were compared with conventional practices. CREAMS-PADDY model was chosen for the paddy nutrient simulation, and two-year field experimental data were used for the model calibration and validation. The validated model was used to evaluate the developed BMP scenarios for the 46 years of simulation period. The observed nutrient loads were 15.2 and 1.45 kg/ha for nitrogen and phosphorus, respectively, and mainly occurred by early season drainage and rainfall runoff in summer. The long-term simulation showed that the soil test-based fertilization and drainage outlet raising practice were the two most effective methods in nutrient loads reduction. The combination of these two resulted in the greatest loads reduction by 29 and 37 % for T-N and T-P, respectively (p value < 0.001). Overall the effectiveness of the BMP scenarios was decreased in the wet season. As the conclusion, outlet height control and soil nutrient-based fertilization were suggested as the effective practices in paddy loads reduction and their combination can be a practicable BMP scenario for the paddy nutrient management.  相似文献   

3.
Two water management practices, an intermittent irrigation scheme using automatic irrigation system (AI) and a spillover-irrigation scheme (SI), were compared for the fate and transport of commonly used herbicides, mefenacet (MF) and bensulfuron-methyl (BSM) in experimental paddy plots. Maximum mefenacet concentrations in paddy water were 660 and 540 μg L−1 for AI and SI plot, respectively. The corresponding values for bensulfuron-methyl were 46.0 and 42.0 μg L−1. Dissipation of the herbicides in paddy water appeared to follow the first-order kinetics with half-lives (DT50) of 1.9–4.5 days and DT90 (90% mass dissipation) of 7.8–11.3 days. The AI plot had no surface drainage, hence no herbicide was lost through paddy-water discharge. However, SI plot lost about 38 and 49% of applied mefenacet and bensulfuron-methyl, respectively. The intermittent irrigation scheme using automatic irrigation system with a high drainage gate was recommended to be a best management practice for controlling the herbicide losses from paddy fields. The paddy field managed by spillover-irrigation scheme may cause significant water and herbicide losses depending on the volume of irrigation and precipitation. The water holding period after herbicide application was suggested to be at least 10 days according to the DT90 index.  相似文献   

4.
The fertilization management of the rice crop in Piedmont was analyzed at a regional scale, and the agronomic and environmental sustainability of the actual fertilization strategy of rice was evaluated through the analysis of its effect on the soils and waters quality. On average, a total amount of 127 kg ha−1 of N, 67 kg ha−1 of P2O5 and 161 kg ha−1 of K2O were supplied to the rice crop. In most cases N and P fertilization was rather well balanced with crop removal. The N balance was in the range ±50 kg for 77% of the surface. The low concentration of N in the groundwater reflected the small N surplus. P fertilization resulted to be smaller than removal for 53% of the surface. Nevertheless, the soil extractable P was very high, probably because of former higher P inputs. This resulted in a high concentration in water courses and aquifers. The K fertilization was excessive (surplus >100 kg ha−1) for 53% of the surface, but most soils showed a low K content. K is probably contributing to nutrient leaching to a great extent. The average soil organic matter (SOM) content of paddy fields was higher than that of normally-cultivated soils in Piedmont, and the C/N was higher, owing to the low mineralization rate in waterlogged conditions. The SOM content was in relation with the management of the crop residues, as the tradition of burning straw after harvest was still widespread on 65% of the paddy surface.  相似文献   

5.
稻鸭共作有机稻生产中几个关键问题的技术探讨   总被引：1，自引：0，他引：1  
2011-2013年在江苏省江阴市开展了稻鸭共作有机稻生产与鸭子安全放养技术的研究。结果表明,提高栽插密度是稻鸭共作有机稻取得高产的关键;40.0℃是稻田鸭子生存的极限高温,在36.0℃～38.5℃的连续高温条件下,通过灌20 cm左右的深水层,并采用边灌边排的方法可有效防止鸭子中暑死亡;将两块稻田隔成一个围养单元,通过两块稻田轮流搁田的方法可有效解决水稻中后期的水分管理。  相似文献   

6.
An experiment was conducted in three fallow paddy fields situated on the mid-tropical plain zone of a northeastern Indian state(Tripura) to provide rice fallow management options using leftover soil moisture and nutrients. The three experimental fields were managed by growing rice under the system of rice intensification as the rainy season crop and then groundnut, lentil, rapeseed and potato as the post-rainy season crops. Fertilization under the integrated nutrient management system and lifesaving irrigation at critical stages of each post-rainy season crop were provided. Results showed that the field water use efficiency values were 5.93, 2.39, 2.37 and 59.76 kg/(hm2·mm) and that the yield of these crops increased by approximately 20%, 34%, 40% and 20% after applying two lifesaving irrigations in groundnut, lentil, rapeseed and potato, respectively. Therefore, fallow paddy field can provide possible profitable crops during the post-rainy season by utilizing the residual moisture and minimum supplemental irrigation under improved nutrient management practices.  相似文献   

7.
Due to the recent regulation of rice production in Japan, it has become necessary to convert rice paddy to other field crops production. To achieve this, drainage conditions, especially for surface drainage, must be improved. We propose the introduction of a slight slope to improve surface drainage, but the optimal slope must be determined in order to prevent soil erosion caused by excessive slope, as well as increased cost. In Japan, a 0.1% slope has recently come into widespread use and, therefore, the impact on surface drainage must be quantified. In this report, observations were carried out to quantify the impact of a 0.1% slope for converted rice paddy and the following results were obtained: (1) An approximate 0.1% slope enables improvement of 46% of the soil surface saturation area as compared to flat conditions about 10 h after inundation; and (2) Inundated water remains on a flat field, while it moves downward toward the end on a sloped field. These results give a basis for determining a slope on a rice paddy in terms of surface drainage improvement. However, the optimal slope should be decided from various perspectives including engineering, agronomy, and economics etc.  相似文献   

8.
Suitable and practicable best management practices (BMPs) need to be developed due to steadily increasing agricultural land development, intensified fertilization practices, and increased soil erosion and pollutant loads from cultivated areas. The soil and water assessment tool model was used to evaluate the present and future proper BMP scenarios for Chungju dam watershed (6,642 km2) of South Korea, which includes rice paddy and upland crop areas. The present (1981–2010) and future (2040s and 2080s) BMPs of streambank stabilization, building recharge structures, conservation tillage, and terrace and contour farming were examined individually in terms of reducing nonpoint source pollution loads by applying MIROC3.2 HiRes A1B and B1 scenarios. Streambank stabilization achieved the highest reductions in sediment and T-N, and slope terracing was a highly effective BMP for sediment and T-P removal in both present and future climate conditions.  相似文献   

9.
Intensive use of chemical fertilizer for crops may be responsible for nitrogen and phosphate accumulation in both groundwater and surface waters. The return flow polluted by nutrients not only results in the limitation of water reuse goals but also creates many environmental problems, including algal blooms and eutrophication in neighboring water bodies, posing potential hazards to human health. This study is to evaluate the N-fertilizer application of terraced paddy fields impacting return flow water quality. Water quality monitoring continued for two crop-periods around subject to different water bodies, including the irrigation water, drainage water at the outlet of experimental terraced paddy field, and shallow groundwater were conducted in an experimental paddy field located at Hsin-chu County, Northern Taiwan. The analyzed results indicate that obviously increasing of ammonium-N (NH4 +-N) and nitrate-N (NO3 ?-N) concentrations in the surface drainage water and ground water just occurred during the stage of basal fertilizer application, and then reduced to relatively low concentrations (<0.1 mg/l and <3 mg/l, respectively) in the remaining period of cultivation. The experimental results demonstrate the potential pollution load of nitrogen can be reduced by proper drainage water control and fertilizer application practices.  相似文献   

10.
Abstract

Rice grain production in a long- term unfertilized paddy field was compared with that in an adjacent paddy field which had been supplied with the standard level of fertilizers in 1980-1998 to elucidate the mechanism of maintained grain production in the unfertilized field. Average grain yield (brown rice) in the unfertilized paddy field was 382.7 g m–2 while that in the fertilized field in the adjacent field was 480.0 g m–2, indicating that 80% of grain production was constantly maintained without supplying any nitrogen fertilizer. The amount of nitrogen absorbed by rice plants for producing 1 g grain was estimated to be 14.1 mg, 55% higher than that in the fertilized field in terms of grain production efficiency. The amount of nitrogen absorbed by rice plants per year in the unfertilized field was calculated to be 5.4 g m–2. This amount of nitrogen should have been supplied annually to maintain the stable grain production for the period of 18 years. Quantitative analysis of nitrogen in the unfertilized field demonstrated that 1.4 g m–2 of nitrogen was supplied from irrigation water containing suspended solids, 0.68 g m–2 from biological fixation, and 9.0 g m–2 from soil, respectively, to maintain the stable grain production. Total nitrogen of soil in the unfertilized paddy field had been maintained at a constant level during these 18 years, suggesting that grain production of around 380 g m–2 (brown rice) could be supported without fertilization for an extended period of time.  相似文献   

11.
《Plant Production Science》2013,16(2):232-241
Abstract

Water availability is one of the determinants of productivity of rainfed lowland rice (Oryza sativa L.). Quantifying water losses from a paddy field, such as deep percolation and lateral seepage, assists estimation of water availability to the rice crop and development of appropriate water management in the lowlands. The main objective of this study was to evaluate paddy water availability and productivity across various soils in Northeast Thailand. The daily rate of downward water flow from standing water in the field (D) varied between 0 and 3 mm day-1 from clayey to sandy soils when the standing water was connected to groundwater table. However, when the standing water was separated from groundwater table, D increased up to 5 mm day-1 on soils with very low clay content in the topsoil. Daily net lateral water flow from the field (L) averaged over the season varied between 5 and 24 mm day-1 for the outflow and between 3 and 16 mm day-1 for the inflow. Both the inflow and outflow tended to be associated negatively with the soil clay content. The seasonal water loss through D plus L during the growing season in the lowlands was also negatively related to the soil clay content. The yield of a major rainfed lowland rice cultivar in Northeast Thailand (KDML105) varied from 2 to 4 t ha-1 across the region, and the water productivity (the ratio of grain yield to cumulative rainfall from transplanting/seedling establishment to maturity) ranged from 3 to 9 kg ha-1 mm-1. High clay soils could provide good standing water until late in the growing season, so the high production efficiency was measured on such soils.  相似文献   

12.
Promoting biomass utilization, the objectives of this study were to clarify the spatial distribution of nitrogen, one of the most important fertilizer components in the methane fermentation digested slurry (i.e., the digested slurry), and to establish an effective method to apply spatial-uniformly digested slurry with irrigation water in the rice paddy field. A numerical model describing the unsteady two-dimensional flow and solution transport of paddy irrigation water was introduced. The accuracy of this model was verified with a field observation. The tendencies of the TN simulated in inlet and outlet portions had good agreement with the measured data and the accuracy of the numerical model could be verified. Using the numerical model, scenario analyses were conducted to determine the method for spatial-uniform application of the digested slurry with irrigation water. The simulated results indicated that drainage of the surface water and trenches at the soil surface were effective for spatial-uniform application of the digested slurry with irrigation water in the rice paddy fields. The effect of the trenches was maximized when the surface water of the rice paddy field was drained adequately.  相似文献   

13.
This paper reviews the constraints and challenges of paddy farming in Taiwan. Based on those evidences, a set of eco-friendly rice farming practices raised by SRI principles are proposed from exploratory SRI trials conducted in Taiwan. The trials show that even with less exact leveling in the SRI field than is ideally provided, the average yield for SRI was higher than for CP; with an aerobic soil situation, the combination of biocontrol agent application and SRI management was seen to give better rice blast control; and the highest paddy yield was obtained from single-seedling transplants from potted nursery trays which protect the young seedlings’ roots from shock or twisting, compared with the planting of more numerous seedlings grown on flat nursery trays by a mechanical rice transplanter. In conclusion, a conceptual framework for eco-friendly paddy farming is formulated to encourage farmers to practice SRI principles. Among the participants in this collaboration, a co-operating group of SRI farmers is organized under investor sponsorship to guarantee the quality and safety of food, integrating an inspection service and food-source traceability from field to market with the production process. It is seen that in Taiwan, SRI principles can be adopted by local farmers without need for additional premiums through eco-friendly collaboration that can raise simultaneously the productivity of land, capital, and irrigation water. In addition, this collaboration can take advantage of increasing consumer demand for safe food with fewer chemicals and for supporting a greater level of biodiversity.  相似文献   

14.
This paper introduces an irrigation system developed in the floodplain of a lake and studies the water management technique of the irrigation system by estimating the total water balance of the whole system. The system is characterized by a reservoir combined with a dike system in the floodplain of the Tonle Sap Great Lake and an irrigation system. Two main models are used for calculating the total water balance. The first model is the water balance of the reservoir. The inputs to the model are water level of the reservoir, precipitation, lake evaporation, infiltration, and area–volume curve of the reservoir. The outputs are inflow and outflow of the reservoir. The supply from the reservoir to paddy fields is computed from the outflow. The second model is the water balance of paddy fields, based on which the water requirement in paddy fields is derived. The reference evapotranspiration needed to calculate the water requirement is simulated for monthly time series using the FAO Penman–Monteith model. Since there is no drainage network in the irrigation system, surface drainage and runoff are not included in the calculation of the water balance, and seepage is considered negligible in the flat floodplain area. The evapotranspiration, rice variety, soil type and irrigated area are used to simulate water consumption in paddy fields. Finally, the two models are connected to produce the total water balance from the reservoir to paddy fields. The total outflow from the reservoir is estimated and the total water consumption for dry season cultivation is also determined. Finally, the efficiency of the whole system is examined.  相似文献   

15.
【目的】旨在通过优化水稻生育进程的水肥供给来促进水稻的生长发育。【方法】大田试验于2016—2017年在黑龙江省八五二农场进行,以垦稻24 (主茎叶片数为12) 为材料,采用2种灌溉模式和2种施肥模式的正交试验设计：叶龄灌溉模式 (LI) 与常规灌溉模式 (RI),叶龄调控侧深施肥模式 (SF) 与常规施肥模式 (RF)。【结果】LI+SF模式对水稻形态特征、光合特性、水肥利用效率及产量具有显著影响(P<0.05)。与RI+RF相比,LI+SF模式使叶面积指数、单株不定根数、总根长、总根表面积及总体积显著提高了21.2%、22.7%、20.8%、45.2%和17.8%,灌浆期水稻光合速率、净光合速率、叶绿素含量及气孔导度显著提高了17.4%、18.4%、26.8%和40.1%,水稻结实率、千粒重和理论产量显著提高了6.3%、2.4%和28.2%,实收产量平均增加5.2%,纯收入增加13.2%,氮肥农学利用率、籽粒吸氮量、产谷利用效率、氮肥偏生产力及氮收获指数被显著提高了11.1%、6.9%、5.8%、13.6%和8.0%。LI模式可以节约灌溉水用量1 000 t/hm2。RI+SF对水稻植株形态、光合特性、生物学产量和水肥利用率具有一定的促进作用,实收产量平均增加2.3%,没有充分发挥水肥耦合作用。【结论】LI+SF模式为本研究最佳的精准灌溉施肥模式,也是适合在我国北方推广的寒地水稻节水、节肥、丰产技术模式。  相似文献   

16.
【Objective】The objective is to improve the growth and development of rice by optimizing water and fertilizer supply in rice growing duration.【Method】A field experiment of fertilization and irrigation under leaf age regulation was conducted in 2016 and 2017 at 852 Farm in Heilongjiang Province. Rice variety Kendao 24 was used as material under two irrigation modes (leaf age irrigation mode, LI; conventional irrigation mode, RI) and two fertilization modes (leaf age regulation side deep fertilization mode, SF; conventional fertilization mode, RF).【Result】Rice morphological traits, photosynthetic characteristics, water and fertilizer use efficiency and grain yield were significantly affected by LI+SF (P< 0.05). Compared with RI + RF, LI+SF significantly increased leaf area index, adventitious root number per plant, total root length, total root surface area and total root volume by 21.2%, 22.7%, 20.8%, 45.2% and 17.8%, respectively. Photosynthetic rate, net photosynthetic rate, chlorophyll contents and stomatal conductance were significantly increased by 17.4%, 18.4%, 26.8% and 40.1%, respectively. Seed setting rate, 1000-grain weight and theoretical yield were significantly increased by 6.3%, 2.4% and 28.2%, respectively. Average yield was increased by 5.2%, and net income was increased by 13.21%. Agronomic efficiency of nitrogen fertilizer, grain nitrogen uptake, grain yield and utilization efficiency, partial productivity of nitrogen fertilizer and nitrogen harvest index were significantly increased by 11.1%, 6.9%, 5.8%, 13.6% and 8.0%, respectively. In addition, 1 000 t/hm2 irrigation water can be saved by LI mode. RI+SF mode can exert a positive influence on plant morphology, photosynthetic characteristics, biological yield and water and fertilizer use efficiency. The average yield was increased by 2.3%. However, the coupling effect of water and fertilizer was not fully exerted.【Conclusion】LI + SF mode is the best precise irrigation and fertilization mode in this study, and it is also suitable to be popularized as a water-saving, fertilizer saving and high-yield technology for rice in the cold area of northern China.  相似文献   

17.
Ponded water convection kinetics should be altered by growth stages of rice plants. We investigated the convective velocity of ponded water in a vegetated paddy field. The convective velocity was measured using the equipment through use of the principle of a hot-wire anemometer, and the temperature profile of the ponded water was measured using lysimeters with and without paddy rice vegetation. The maximum convective velocity in a vegetated plot was 0.7 mm s−1, slower than the maximum velocity in an unvegetated plot, which was 1.6 mm s−1. The convective velocity in a vegetated plot increased slightly when the temperature of the surface water was higher than that near the soil, between 09:00 and 17:00.  相似文献   

18.
为探究养分专家系统推荐施肥下磷肥用量的减施潜力,进而为不同肥力水平稻田磷肥减施提供理论依据,在高、中、低肥力稻田上,通过在养分专家系统推荐施肥基础上增减15%、30%、45%磷肥用量开展双季稻田间试验,并分析磷肥用量与水稻产量的量化关系。结果表明,在高、中、低肥力稻田上,养分专家系统推荐施肥处理的早、晚稻产量均呈高肥力>中肥力>低肥力的趋势,而与之比较,在其基础上磷肥增施15%、30%、45%处理对早、晚稻产量均无显著增产效应,减施15%处理未显著减产,但磷肥减施45%处理在各肥力水平稻田上均显著减产,降幅为4.06%~15.15%。高、中、低肥力稻田上早、晚稻产量潜力对应磷肥合理用量呈低肥力>高肥力>中肥力稻田的趋势,且在95%的产量潜力下,在养分专家系统推荐施肥量基础上,早稻季不同肥力水平稻田上可减施磷肥27.09%~57.58%,晚稻季可减施磷肥33.25%~50.53%,其中早、晚稻磷肥可减施比例高肥力稻田为27.09%、49.51%,中肥力稻田为36.20%、50.53%,低肥力稻田为33.25%、57.58%。在养分专家系统推荐施肥量基础上,可在不同肥力水稻田上实现磷肥减施,但减施比例有所差异,整体上高肥力稻田磷肥可减施比例较中、低肥力稻田低。  相似文献   

19.
South Korea is located in the Asian monsoon region, and paddy rice farming is one of the important agricultural activities, which may contribute to the non-point source pollution of inland water bodies along with rainfall runoff. The status of water quality in rural streams located throughout South Korea was examined in this study by water quality monitoring and statistical analysis. Totally six surveys were conducted in 2003 and 2005 to monitor 300 streams located in rural subwatersheds; these streams are affected by agricultural activities and water supply for agricultural practices. The monitoring was performed at the terminal point of each subwatershed. In each study year, the streams were monitored in the three hydrological periods (April, July, and October) to observe differences in the impacts of agricultural activity and rainfall pattern. During the surveys, 15 water quality parameters were measured and interpreted using multivariate statistical methods including factor analysis and cluster analysis. Results show that the water quality of the rural streams monitored in this study appeared to meet the Korean water quality criteria for agricultural use, which are 8.0 and 100 mg/L for biochemical oxygen demand and suspended solids, respectively. In terms of organic contamination and suspended solids, the best stream water quality was observed in October compared to other periods. This can be attributed to the fact that October follows the rice-harvesting period and has low rainfall; thus the streams are probably less affected by agricultural activities and surface runoff. The three hydrological periods did not show much variation in the nitrogen and phosphorus parameters related to stream water nutrient conditions. Factor analysis indicates that the first five factors for April explained about 67% of the total sample variance. In July, the first four factors explained about 60% of the total variance, while the first four factors for October explained about 65%. Cluster analysis reveals that the streams could be divided into four groups in April and October and five groups in July. The box-and-whisker plots of the physicochemical variables indicate that Group A had the best water quality among the groups. This study demonstrates that the rural stream water quality of South Korea in the Asian monsoon region can be greatly affected by agricultural activities such as paddy rice farming and rainfall patterns.  相似文献   

20.
Rice husk charcoal (RC) produced from the pyrolysis of rice husk (RH) can be one of the cost-effective biochars for use in rice-based farming systems. This study investigated changes in rice yield and soil carbon sequestration over three years of RC application to an Andosol paddy field. The treatments were RC application at 0.02, 0.2, and 2 kg m?2 (RC0.02, RC0.2, and RC2, respectively), RH application at 0.2 kg m?2 (RH0.2), and a control with no RC or RH application (CONT). The results showed that RC2 increased culm length by 4% and straw weight by 14% on average over the three years. These increases in plant growth coincided with a higher level of silicon uptake by the rice plants, although they did not significantly affect grain yield. The soil carbon content was progressively increased by RC2 over the three years, whereas it was not significantly affected by RC0.02 or RC0.2. A considerable amount (>72%) of the applied carbon with RC2 remained in the soil by taking account of its downward movement below the 10 cm layer of the paddy field after three consecutive years of RC application. We conclude that rice husk charcoal application to Andosol paddy fields is an effective option for increasing carbon sequestration. Furthermore, the increase in silicon uptake by rice plants suggests that rice husk charcoal can also be functioning as a silicon fertilizer.  相似文献   

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