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1.
This experimental study assesses the effects of event rainfall on soil erosion characteristics in terraced rice paddy fields. A 0.75-ha terraced paddy field located in Northern Taiwan was used to investigate the soil erosion under the regular cultivation of rice during two crop seasons. The environmental changes were investigated in the neighboring areas in which terraced paddy fields have been converted to other land usages. The annual rate of soil erosion calculated from the observed rainfall runoff and suspended solid contained was 0.77 ton/ha, which is significantly less than the erosion rate associated with upland crop cultivation reported by other research conducted in Taiwan. Experimental results also showed that the terraced paddy field retained the highest percentages of clay, silt, and organic matter's content, as compared to those of other upland crops, indicating that the topsoil was less susceptible to rainfall erosion under flooded conditions of rice-cultivation. The results of this study show that the rice-planted terraced paddy offers the highest level of soil conservation. The function of soil and water conservation in terraced paddy fields could be further increased by effective maintenance of embankment and to raise the height of the bund. Poor management, abandoned cultivation, and converse to other upland crops of terraced paddy fields are regarded as major contributors to increased soil erosion in mountainous areas. The government in Taiwan should formulate effective measures and maintain sustainable rice cultivation in the terraced paddies. 相似文献
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Ratan Kumar Ganapati Shahzad Amir Naveed Sundus Zafar Wang Wensheng Xu Jianlong 《水稻科学》2022,29(5):412-434
Salinity-alkalinity is incipient abiotic stress that impairs plant growth and development. Rice (Oryza sativa) is a major food crop greatly affected by soil salinity and alkalinity, requiring tolerant varieties in the saline-alkali prone areas. Understanding the molecular and physiological mechanisms of saline-alkali tolerance paves the base for improving saline-alkali tolerance in rice and leads to progress in breeding. This review illustrated the physiological consequences, and molecular mechanisms especially signaling and function of regulating genes for saline-alkali tolerance in rice plants. We also discussed QTLs regarding saline-alkali tolerance accordingly and ways of deployment for improvement. More efforts are needed to identify and utilize the identified QTLs for saline-alkali tolerance in rice. 相似文献
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以昌江黎族自治县(昌江县)为研究区,借助于空间分析手段,分析区内第2次土壤普查期间到2009年土壤耕层土壤pH的时空变异特征,并阐述其主要成因.结果表明,在气候、地形、母质、植被等自然因素共同作用下,20世纪80年代研究区土壤pH在西北到东南方向上有逐级降低的特征.区内2009年土壤pH值低于第2次普查期间,且空间变异度变小,平均值由6.0降至5.8;土壤pH分布受施肥、工矿等人为生产活动的影响,原有的空间分布格局有所改变,主要表现在昌化、海尾、乌烈等地土壤出现酸化特征. 相似文献
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1995～2006年,淮安市水稻种植面积、单产、总产随着农业产业结构调整、价格波动以及良种补贴、粮食直补等惠农政策的实施,呈现同步变化特征。水稻种植面积占粮食种植面积的41.21%～47.46%,总产占粮食总产的54.11%～62.16%。淮安市水稻生产具有良好的自然条件,土壤肥沃、水资源丰富,机械化程度高,但也存在着缺少与高产优质多抗相协调的品种,生产规模化程度低、产业化经营不发达、专业化服务不配套等问题,制约了淮安市水稻的可持续发展。提出了将淮安建成国家级水稻生产基地和优质稻米基地的对策。 相似文献
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Wise use of paddy rice fields to partially compensate for the loss of natural wetlands 总被引：1，自引：0，他引：1
Chun G. Yoon 《Paddy and Water Environment》2009,7(4):357-366
This paper reviews the scientific information related to climate change impacts on wetlands and functions of human-made wetlands
such as paddy rice field and treatment wetland are described to partially compensate for the loss of natural wetlands. Wetlands
are among the world’s most productive environments and are cradles of biological diversity, providing the water and primary
productivity upon which countless species of plants and animals depend for survival. Considerable evidence suggests that some
global warming is occurring, which has important implications for wetland system as well as human life and wildlife. Direct
effects of climate change on wetlands are likely to be accentuated by human induced changes that will increase stress to wetland
ecosystems. The Ramsar Classification System for Wetland Type provides three broad categories: marine/coastal wetlands, inland
wetlands, and human-made wetlands. Human-made wetlands are as important as natural wetlands, and the largest human-made wetland
is a paddy rice field (130,000,000 ha) taking about 18% of total global wetland, which is second only to natural fresh wetlands.
Paddy rice fields provide not only rice production for food, but also diverse multi-functionalities such as flood control,
groundwater recharge, soil erosion control, water quality purification, air purification and cooling, wildlife habitat, amenity
and social benefits. The economic value of multi-functionalities estimated by contingent valuation method (CVM) and travel
cost method was in the range of U$ 9.75–11.46 billion, which is greater than the value of rice production itself in Korea.
Unfortunately, there is an indication of decreased area in paddy rice field in Korea after 1990 showing about 20% decrease
in 15 years. Another human-made wetland type is a constructed wetland for water purification, and thousands hectares of wetlands
are scheduled to be constructed for reservoir water quality improvement in next 5 years in Korea, and their application is
expected to be more common in near future. There is a growing consensus that wetlands are critically important ecosystems
that provide globally significant social, economic and environmental benefits. Wise use of human-made wetlands is as important
as conservation of natural wetlands, which can be a viable element to overall climate change mitigation and can partially
compensate for the loss of natural wetlands. 相似文献
9.
Soil erosion by water is a common environmental problem which can affect the sustainable development and the agriculture of
developing countries especially. Therefore, several countries, threatened by this phenomenon, adopt different measures to
preserve and protect their natural resources. The main purpose of this study was to identify vulnerable areas to establish
a soil erosion risk map in Tunisia. In order to do so, an approach based on a combination of the Revised Universal Soil Loss
Equation (RUSLE) as an erosion model, Geographic Information System (GIS) and Remote Sensing was applied. RUSLE, which is
a model to predict soil loss, is composed of five factors. Erosivity factor (R factor), erodibility factor (K factor), topography factor (LS factor), crop management factor (C factor), and supporting practices factor (P factor). Furthermore, in order to get the most accurate C factor for each land use, times series Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation index (MODIS-EVI)
were used. MODIS-EVI time series was helpful for distinguishing vegetation dynamics with taking into account phenological
variation of the crops. The results indicated that Tunisia has a serious risk of soil erosion. Indeed, about 24.57% of our
study area had a soil loss rate more than 30 t/ha. In these areas, suitable and urgent measures and treatments should be required.
Finally, this approach which is based on remote sensing techniques, GIS and erosion model can be useful for planning appropriate
environmental decision-making policy in a global scale. 相似文献
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Rice fields are ecosystems with many types of plants, microbes, invertebrates, birds and animals. The rice farming protects the biodiversity of the region and maintains the ecosystem for the benefit of environment. Some rice varieties release biocidal allelochemicals which might affect major weeds, microbial and pathogenic diversity around rice plants, even soil characteristics. A large number of compounds such as phenolic acids, fatty acids, indoles and terpenes have been identified in rice root exudates and decomposing rice residues, as putative allelochemicals which can interact with surrounding environment. Since these allelopathic interactions may be positive, they can be used as effective contributor for sustainable and eco-friendly agro-production system. Genetic modification of crop plants to improve their allelopathic properties and enhancement of desirable traits has been suggested. Development of crops with enhanced allelopathic traits by genetic modification should be done cautiously, keeping in view of the ecological risk assessment(non-toxic and safe for humans and ecosystem, crop productivity, ratio of benefit and cost, etc.). 相似文献
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随着种植业结构的调整,景宁畲族自治县农业部门在部分高山探索出以传统作物,春马铃薯、赤皮稻、萝卜进行新布局,引进新良种、推广新技术,得到山区农民的直观效果,取得了明显社会和经济效益。通过＂春马铃薯—赤皮稻—萝卜＂三熟制的种植,山区农民易接受,其产品适应市场的需求,尤其在高山生产无化学污染,为农产品安全提供得天独厚的条件。通过水旱轮作,能保持土壤的团粒结构,具有保水保肥能力,增强土壤里的通透性,有利农作物的根系生产。该整套的春马铃薯、赤皮稻、萝卜的栽培技术要点,可供同纬度的种植地带借鉴。 相似文献
12.
Grasslands in ‘Old World’ and ‘New World’ Mediterranean‐climate zones: past trends,current status and future research priorities 
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下载免费PDF全文 C. Porqueddu S. Ates M. Louhaichi A. P. Kyriazopoulos G. Moreno A. del Pozo C. Ovalle M. A. Ewing P. G. H. Nichols 《Grass and Forage Science》2016,71(1):1-35
Despite their ecological, economic and social importance, grasslands in areas with Mediterranean climates continue to receive limited scientific, political and media attention. The main objectives of this review are to compare and contrast dryland grasslands in the ‘Old World’ regions of the Mediterranean basin (southern Europe, western Asia and North Africa) with those of ‘New World’ regions with Mediterranean climates (Australia and Chile) and to identify common research priorities. The common characteristics and differences in climate, soils, native vegetation, importance of the livestock sector and the socio‐economic background for the different Mediterranean environments are examined. Past trends and the current status of temporary and permanent Mediterranean grasslands are also described. Some common issues between these regions are as follows: (i) adaptation to climate change; (ii) increasing persistence and drought survival of both annual and perennial species; (iii) the important role of forage legumes; (iv) maintaining grassland plant diversity; and (v) improved ecosystem services, such as carbon sequestration, control of soil erosion and wildfires, and preservation of both wild and domestic biodiversity. The favourable climate in these regions, which allows year‐round grazing and the growth of legumes, should be exploited to improve the sustainability of grassland‐based, extensive farming systems and the quality of their animal products, while at the same time improving ecosystem services. The decreasing support for grassland research and development programmes requires increased international scientific and technical cooperation among the few institutions operating in the different Mediterranean‐climate areas of the World to provide innovative and sustainable solutions to farmers. 相似文献
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苍梧县崩岗洪积扇农田土壤理化特性 总被引：1，自引：0，他引：1
崩岗是中国南方最严重的土壤侵蚀类型之一，给土地资源带来了相当大的威胁，尤其是崩岗产生的洪积物严重影响到洪积扇农田的土壤性质。分别选择苍梧县龙圩镇崩岗洪积扇果园和稻田为研究对象，探讨洪积扇土壤理化特性。结果表明：崩岗侵蚀导致洪积扇农田土壤退化，土壤性质均显著弱于对照区，同时由扇顶到扇缘，土壤容重呈现减小的趋势，孔隙度和饱和含水量呈增加的趋势，土壤砾石和砂粒含量均逐渐减少，粉粒和粘粒含量则逐渐增加，养分也随之呈增加趋势。Pearson相关分析显示，土壤容重、砾石、砂粒与土壤养分指标呈负相关关系，土壤孔隙度、饱和含水量、粉粒、粘粒与土壤养分指标呈正相关关系。 相似文献
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《Journal of Crop Improvement》2013,27(1):41-48
Summary Southern China has abundant natural resources and is a major region of agricultural production. However, soil erosion is increasingly threatening the agricultural productivity of this region. Increases in soil erosion are caused by improper land use practices with soils of high rainfall erosivity. Much of the area prone to accelerated erosion was previously forested and subsequently logged four times since the 1920s. This paper discusses the effects of biological control practices on soil erosion according to erosion types, soil properties, and terrain. 相似文献
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生物可降解膜覆盖对机插水稻生长和稻米品质的影响 总被引：1，自引：0，他引：1
【目的】研究并明确不同生态区生物可降解膜覆盖对机插水稻生长和稻米品质的影响,为实现水稻生态种植提供方法。【方法】以生产上大面积应用的五优稻4号、鄂早18及甬优538为试验材料,在北方单季稻、南方早稻及单季稻三种种植类型中设置生物可降解膜覆盖处理及不覆膜处理,研究不同生态区水稻生物可降解膜覆盖机插对土壤温度、水稻生长和稻米品质的影响。【结果】1)增温效果：北方覆膜水稻增温效果更好,增温效应主要集中在生育前期,特别是在移栽到穗分化期这段时间。与对照相比,土壤日平均增温2.76℃;2)生育期变化：南北方覆膜水稻均缩短了水稻生育期,北方覆膜水稻提前7 d成熟,南方两种种植方式覆膜处理均提前3 d;3)叶龄：无论南北方覆膜均能促进水稻叶片生长,增加出叶速率,在生育前期北方覆膜水稻的出叶数比对照多0.6~0.9叶;4)株高：南北方覆膜水稻均降低水稻株高,北方覆膜水稻显著降低了5.7cm;5)茎蘖数:北方单季稻覆膜处理促进了水稻分蘖的早发快长,与对照相比,显著提高有效茎蘖数35.7万个/hm2;6)干物质积累量：北方覆膜水稻在穗分化期、齐穗期及成熟期干物质积累量均显著大于对照,南方覆膜早稻在成熟期的干物质积累显著大于对照;南方单季稻在齐穗期的干物质积累显著小于对照;7)增产效果：南北方覆膜水稻都有显著增产效果,北方增产效果更好,增产达到了8.7%,南方早稻增产7.9%,南方单季稻增产4.1%;8)稻米品质：北方覆膜水稻显著提高了糙米率、精米率及蛋白质含量;南方单季稻覆膜处理显著提高了整精米率,南方早稻也得到相同结果,但未达到显著水平。【结论】生物可降解膜覆盖机插种植模式在两个生态区均能促进水稻的生长发育,提高水稻产量;对于稻米品质,北方覆膜水稻提高了稻米加工品质,而食味品质下降,南方覆膜水稻提高了加工品质,而外观品质变劣;将南北覆膜水稻进行比较发现,生物可降解膜覆盖机插种植模式对北方水稻有更好的促进生长作用及增产效果,并且降低了水稻覆膜生产中塑料薄膜对环境的污染,为水稻绿色优质生产提供新的途径。 相似文献
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Li-Ling Lin Chao-Wen Wang Cheng-Lung Chiu Yung-Chuan Ko 《Paddy and Water Environment》2011,9(2):257-266
In recent years, frequent attacks of heavy rain and typhoon have severely devastated the vulnerable mountains of Taiwan; slopelands
are artificially disturbed by improper development and utilization. People are getting more aware of the importance of slopeland
preservation as well as disaster prevention and mitigation. The government, realizing the criticality of gradually worsened
land safety issues, has also set forth the “Draft of National Land Planning Act” and the “Draft of Regulations on Land Preservation
Act” in the purposes of rehabilitating the excessively explored ecosystems and diminishing the development extent of environmentally
susceptible areas, so as to effectively preserve soil, water, and organism resources and to achieve perpetual development
of national lands. “Classification of Slopeland Utilization Limitations” is a critical link to national land preservation.
The classification is based on four factors, namely average slope, effective soil depth, soil erosion, and parent rock, with
different utilization zones defined as bases of landuse planning. However, current classification results of the environmentally
susceptible and disaster-prone mountain lands are mostly defined as suitable for forestry or husbandry. Scattered allocation
of these lands results in critical issues such as segmented landuse and impaired landscape and ecotype. It is necessary to
re-adjust land resources planning and usage management. Therefore a review of the current standards for classifying slopeland
utilization limitations is proposed to facilitate rational allocation of slopeland use. Jhuoshuei River is selected as the
scope of the case study, with data of debris flows induced by the typhoon Toraji in 2001 as the training data. Eight susceptibility
factors, which include form factor of watershed, integral hypsometric, slope of main stream, density of stream network, density
of road network, area ratio of historical landslide, and area ratio of triggered landslide, together with the total rainfall
of the storm event as the triggering factor, are selected for creating the debris flow susceptibility model by employing the
logistic regression within the multivariate geostatistics analysis. This model interprets the curve of success ratio of debris
flows triggered by typhoon Toraji, of which the area under the curve is as high as 74.3%. The debris flow susceptibility model
created in the study takes the Feng-Chiu section of Sinyi Township, Nantou County, Taiwan within the Jhuoshuei River as the
scope of research. GIS technology has been applied in the feasibility study of classification standards. New concepts have
been further proposed in view of national land preservation addressing the medium and high elevation disaster-prone areas
that are not suitable for agricultural use, for standard revision reference. 相似文献
17.
Inhong Song Ik-Jae Kim Dae Ho Han Myeong-Seop Byeon Jae-Kwan Lee Moon-Seong Kang 《Paddy and Water Environment》2012,10(1):49-58
A majority of streams in Korea have been channelized and their adjacent flood plains have been converted for anthropogenic
land use, especially in urbanized areas. Fortunately, recent elevated public recognition to the stream ecosystem has led to
governmental efforts to conserve riparian areas. In this study, a simple method to prioritize locations for riparian establishment
was developed at a watershed scale based on spatiotemporal change of riparian forest area. The developed method was applied
for the Ansung and Sapkyo watersheds, which were under consideration for the stream riparian area establishment by the Korean
Ministry of Environment. Two riparian forest indices, Riparian Forest Index (RFI) and Riparian Forest Change Index (RFCI)
were developed to represent spatial and temporal change of watershed riparian forest, respectively. LANSAT satellite images
with a 30 m × 30 m resolution were used to estimate the two riparian forest indices. A precautionary approach, which intends
to preserve the existing riparian forests as much as possible, was applied by ranking sub-watersheds based on the two riparian
forest indices to prioritize locations for the riparian establishment at a sub-watershed level. The results showed that overall
urban land cover in riparian areas increased while forests and cropland decreased over the past 25 years. More importantly,
riparian forest removal occurred more rapidly in the riparian area, which is one of the most important niches for riparian
ecosystems, as compared to the entire watershed. Most riparian forests appeared to be located upstream of the watersheds,
and thus it is important to develop management measures to preserve existing riparian forests from human activities. The developed
approach could be a useful tool that can assist policy makers to prioritize locations for the riparian area establishment.
However, this method has limitations of only considering riparian forest area and therefore, other aspects such as stream
morphology as well as ecology needs to be incorporated into riparian area determination process as they become available in
the future. In addition, considering that substantial portions of riparian areas have already been disturbed, the restoration
aspect of the impaired riparian also needs to be investigated further. 相似文献
18.
Quynh Vu Angelee F. Ramal James M. Villegas Alexandra Jamoralin Carmencita C. Bernal John M. Pasang Maria Liberty P. Almazan Daniel Ramp Josef Settele Finbarr G. Horgan 《Paddy and Water Environment》2018,16(2):379-390
The diversification of farming landscapes is proposed as a method to increase farm productivity while at the same time enhancing pest regulation services provided by the natural enemies of insect herbivores. In this study, areas of diversified and conventional rice fields (with 2–14 fields per area?=?0.42–1.31 ha) were established at three sites in the Philippines. The diversified areas had a series (>?40 per hectare) of small (<?2 m2) vegetable patches interspersed along rice bunds (levees). The abundance of planthopper and lepidopteran pests in these areas was monitored during two consecutive cropping seasons using sweep nets with rice yield and damage recorded at the end of each season. Mortality of brown planthopper (Nilaparvata lugens) and yellow stemborer (Scirpophaga incertulas) eggs was monitored through field exposures of infested rice plants. There were no differences in rice yields between the conventional and diversified areas; however, a range of vegetables were produced as a supplementary product from the diversified rice areas. Diversification had no effect on planthopper or leaffolder (Cnaphalocrocis medinalis) abundance at the sites. Adult stemborers (Scirpophaga incertulas) were more abundant in the diversified areas; however, stemborer damage was similar between area treatments in both years. Vegetable patches did not increase parasitism of planthopper eggs; however, egg parasitism was highest close to the vegetable patches, suggesting that egg parasitoids interacted with the patches. Mortality of stemborer eggs was higher in the diversified areas than in the conventional areas. Parasitism due to Trichogramma japonicum and other egg parasitoids was also higher in the diversified areas. These results indicate the potential for vegetable patches to enhance the biological control services provided by egg parasitoids in rice fields; however, the study also indicates a need to carefully select vegetable crops that avoid any potential benefits for rice pests. We discuss the need for further research into diversified farms as a means of achieving sustainable rice production in Asia. 相似文献
19.
Yoshiyuki Shinogi Yutaka Kanri Yuichi Hirose Kaneto Inoue 《Paddy and Water Environment》2005,3(3):165-170
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