scholarly journals The relationships between the management history and vegetation types of fallow paddy field and abandoned paddy fields

2005 ◽  
Vol 24 (Special_Issue) ◽  
pp. S7-S12 ◽  
Author(s):  
Yoshinobu Kusumoto ◽  
Toshiya Ohkuro ◽  
Makoto Ide
Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 353
Author(s):  
Ya-Wen Chiueh ◽  
Chih-Hung Tan ◽  
Hsiang-Yi Hsu

In the face of climate change, extreme climates are becoming more frequent. There were severe droughts in Taiwan in 2020, 2014–2015, and 2002. In these years, the paddy fields were kept fallow to save water and transfer agricultural water to non-agricultural use. On the other hand, with global warming, the existence of paddy fields may be one of the natural solutions to regional temperature mitigation. This study used remote sensing to quantify the difference in temperature between paddy fields and urban areas. The result of overall surface temperature deductive analysis revealed that the temperature in the whole Taoyuan research area was 1.2 °C higher in 2002 than in 2003 because of fallowing of the paddy field, while in the Hsinchu research area, it was 1.5 °C higher in 2002 than in 2003, due to the same reason described above. In terms of the difference in land use, for the Hsinchu research area, the surface temperature deductive result showed that the average paddy field temperature in 2002 was 22.3 °C (sample area average), which was 7.7 °C lower than that of the building and road point and 4.3 °C lower than that of the bare land point. The average paddy field temperature in 2003 was 19.2 °C (sample area average), which was 10.1 °C lower than that of the building and road point and 8.3 °C lower than that of the bare land point. Then this study evaluated the economic valuation of the paddy field cooling effect using the contingent valuation method. Through the paddy field cooling effect and in the face of worsening extreme global climate, the willingness to pay (WTP) of the respondents in Taiwan for a decrease of 1 °C with regard to the regional microclimate was evaluated. It was found that people in Taiwan are willing to pay an extra 8.89 USD/per kg rice/year for the paddy for a decrease in temperature by 1 °C in the regional microclimate due to the paddy field. Furthermore, this study applied the benefits transfer method to evaluate the value of a decrease of 1 °C in the regional microclimate in Taiwan. The value of a decrease of 1 °C in the regional microclimate in Taiwan is 9,693,144,279 USD/year. In this regard, the economic value of 1 °C must not be underestimated. In conclusion, more caution is needed while making decisions to change the land use of paddy fields to other land uses.


2020 ◽  
Vol 12 (5) ◽  
pp. 2094
Author(s):  
Di Zhao ◽  
Junyu Dong ◽  
Shuping Ji ◽  
Miansong Huang ◽  
Quan Quan ◽  
...  

Soil organic carbon (SOC) concentration is closely related to soil quality and climate change. The objectives of this study were to estimate the effects of contemporary land use on SOC concentrations at 0–20 cm depths, and to investigate the dynamics of SOC in paddy-field soil and dry-land soil after their conversion from natural wetlands (20 and 30 years ago). We investigated the dissolved organic carbon (DOC), light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and other soil properties (i.e., moisture content, bulk density, pH, clay, sand, silt, available phosphorous, light fraction nitrogen, and heavy fraction nitrogen) in natural wetlands, constructed wetlands, fishponds, paddy fields, and soybean fields. The results indicated that the content of DOC increased 17% in constructed wetland and decreased 39% in fishponds, and the content of HFOC in constructed wetland and fishponds increased 50% and 8%, respectively, compared with that in natural wetlands at 0–20 cm. After the conversion of a wetland, the content of HFOC increased 72% in the paddy fields and decreased 62% in the dry land, while the content of DOC and LFOC decreased in both types. In the paddy fields, LFOC and HFOC content in the topmost 0.2 m of the soil layer was significantly higher compared to the layer below (from 0.2 to 0.6 m), and there were no significant differences observed in the dry land. The findings suggest that the paddy fields can sequester organic carbon through the accumulation of HFOC. However, the HFOC content decreased 22% after 10 years of cultivation with the decrease of clay content, indicating that paddy fields need to favor clay accumulation for the purpose of enhancing carbon sequestration in the paddy fields.


2018 ◽  
Vol 16 (4) ◽  
pp. 352-358 ◽  
Author(s):  
Junichi Kashiwagi ◽  
Koji Hamada ◽  
Yutaka Jitsuyama

AbstractDirect sowing of rice in a flooded paddy field is a beneficial cultivation practice for water use and labour efficiency, compared to the transplanted cultivation. However, a drastic reduction in seedling emergence under flooded paddy fields is a serious constraint especially when the seeds fell at deeper soil layers. Suitable rice germplasm for the direct sowing in flooded paddy fields could ensure the success of this cultivation practice. Instead of laborious field-based screening systems, a pot-based screening method was adopted for simplicity and efficient evaluation of seedling emergence of a subset of world rice germplasm (n = 75) at different sowing depths. As a result, two rice genotypes, ‘Vary Futsi’ (landrace from Madagascar, non-glutinous, subspecies Indica) and ‘Dahonggu’ (landrace from China, non-glutinous, subspecies Indica), with consistently better seedling emergence were identified from a wide range of rice germplasm. These genotypes could serve as excellent parents for the breeding program in developing new rice cultivars with the improved seedling emergence in flooded paddy fields. There were no significant differences in the seedling emergence rate in flooded paddy conditions among the groups from various agro-geographical regions.


2020 ◽  
Vol 2 (1) ◽  
pp. 48-54
Author(s):  
Mhd Zakaria

The purposes of this research are to know the level of paddy field degradation, mapping level of paddy field degradation and analyze effort of paddy field rehabilitation in Beringin Subdistrict of Deli Serdang Regency of North Sumatera Indonesia to increase rice productivity. This research was conducted in Medan Krio Village, District Sunggal Regency Deli Serdang of North Sumatera. The study was conducted in March to July 2017. This research used nonfactorial Randomized Block Design (RBD) with 5 levels organic dosage treatment of Compost Waste City, i.e: B0: Control, B1: Dose 1.5% (36,00 ton/ha), B2: Dose 3% (72,00 ton/ha), B3: Dose 4.5% (108,00 ton/ha), B4: Dose 6% (144,0 ton/ha). The parameters that will be analyzed are the physical, chemical and biological properties of soil in paddy fields. The result showed, treatment with Dose 6% (B4) can (1) improve physical properties of soil Bulk Density, Porosity and the effective depth of soil; (2) increase the C-organic content, N-Total levels of P-Available, CEC soil, and low C/N Ratio; (3) increase Soil organic matter and total Microbes. So, Treatment Dose 6% (B4) of compost waste city gives the best effect to the physical, chemical and biological properties of soil in paddy fields


Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4082 ◽  
Author(s):  
Zhengjun Qiu ◽  
Nan Zhao ◽  
Lei Zhou ◽  
Mengcen Wang ◽  
Liangliang Yang ◽  
...  

Using intelligent agricultural machines in paddy fields has received great attention. An obstacle avoidance system is required with the development of agricultural machines. In order to make the machines more intelligent, detecting and tracking obstacles, especially the moving obstacles in paddy fields, is the basis of obstacle avoidance. To achieve this goal, a red, green and blue (RGB) camera and a computer were used to build a machine vision system, mounted on a transplanter. A method that combined the improved You Only Look Once version 3 (Yolov3) and deep Simple Online and Realtime Tracking (deep SORT) was used to detect and track typical moving obstacles, and figure out the center point positions of the obstacles in paddy fields. The improved Yolov3 has 23 residual blocks and upsamples only once, and has new loss calculation functions. Results showed that the improved Yolov3 obtained mean intersection over union (mIoU) score of 0.779 and was 27.3% faster in processing speed than standard Yolov3 on a self-created test dataset of moving obstacles (human and water buffalo) in paddy fields. An acceptable performance for detecting and tracking could be obtained in a real paddy field test with an average processing speed of 5–7 frames per second (FPS), which satisfies actual work demands. In future research, the proposed system could support the intelligent agriculture machines more flexible in autonomous navigation.


2011 ◽  
Vol 8 (12) ◽  
pp. 3809-3821 ◽  
Author(s):  
A. Meijide ◽  
G. Manca ◽  
I. Goded ◽  
V. Magliulo ◽  
P. di Tommasi ◽  
...  

Abstract. Rice paddy fields are one of the greatest anthropogenic sources of methane (CH4), the third most important greenhouse gas after water vapour and carbon dioxide. In agricultural fields, CH4 is usually measured with the closed chamber technique, resulting in discontinuous series of measurements performed over a limited area, that generally do not provide sufficient information on the short-term variation of the fluxes. On the contrary, aerodynamic techniques have been rarely applied for the measurement of CH4 fluxes in rice paddy fields. The eddy covariance (EC) technique provides integrated continuous measurements over a large area and may increase our understanding of the underlying processes and diurnal and seasonal pattern of CH4 emissions in this ecosystem. For this purpose a Fast Methane Analyzer (Los Gatos Research Ltd.) was installed in a rice paddy field in the Po Valley (Northern Italy). Methane fluxes were measured during the rice growing season with both EC and manually operated closed chambers. Methane fluxes were strongly influenced by the height of the water table, with emissions peaking when it was above 10–12 cm. Soil temperature and the developmental stage of rice plants were also responsible of the seasonal variation on the fluxes. The measured EC fluxes showed a diurnal cycle in the emissions, which was more relevant during the vegetative period, and with CH4 emissions being higher in the late evening, possibly associated with higher water temperature. The comparison between the two measurement techniques shows that greater fluxes are measured with the chambers, especially when higher fluxes are being produced, resulting in 30 % higher seasonal estimations with the chambers than with the EC (41.1 and 31.7 g CH4 m−2 measured with chambers and EC respectively) and even greater differences are found if shorter periods with high chamber sampling frequency are compared. The differences may be a result of the combined effect of overestimation with the chambers and of the possible underestimation by the EC technique.


2019 ◽  
pp. 91-125
Author(s):  
Jaeho Ahn

Songgungni Culture, formed in the late Bronze Age of Korean peninsula, is characterized by the increased power of chieftains, uses of bronzeware, and constructions of huge burial mounds known as Guhoekmyo. The discussion on the difference of Songgungni Culture from previous cultural forms has been divided into the view to see it as foreign influences and that to see it derived from the previous local cultures. The author suggested the latter view first in 1992 but the findings accumulated since then lead us to rethink the origin of Songgungni Culture from a perspective that conjoins these two oft-conflicting views. The Zhou Dynasty and paddy field agrarian culture in the lower area of the Yangtze River influenced the formation of Songgungni Culture given the following findings. First, the Zhou Dynasty’s ceramic art called Beating Technique was discovered in Songgungni Culture with other artifacts such as weights made of stone, bottom parts of Chinese earthenware, and the jar coffins indicating the existence of ascribed status. Second, the excavations of paddy fields, Yunnan- style kilns, independent pillar structures, flask-shaped storage holes, and pestles suggest the propagation of the paddy field rice culture of the lower Yangtze along the coastline of the Shandong Peninsula. Under these foreign influences, Songguk-ri type potteries and other creative agricultural tools were produced. The differentiation of the previous joint family system into the nuclear produced lots of downsized dwelling areas which characterize Songguk-ri culture. And the innovation in the yielding capacity made possible by paddy fields also shows an aspect of Chiefdom settled into this area during the time. The surplus production of this period was not enough to advance towards the autonomous production of bronzeware. The increased size of chieftains’ tombs did not contain enough burial goods. Given the aforementioned findings, Songgungni Culture could be understood as an early stage of Chiefdom, just getting out of the state of fragmented society.


Nematology ◽  
2010 ◽  
Vol 12 (3) ◽  
pp. 373-380
Author(s):  
Katsumi Togashi ◽  
Shigeru Hoshino

AbstractThis study aimed to determine the spatial distribution patterns of Aphelenchoides besseyi among Oryza sativa seeds on panicle, plant hill, and paddy field spatial scales and to present a three-stage sampling method for estimating the mean density per seed in paddy fields. Living and dead nematodes were extracted individually from 20 seeds sampled from each of five panicles, which were sampled from each of six rice plant hills in each of eight paddy fields, where all plants had leaves exhibiting the 'white tip' symptom. Nested ANOVA indicated that A. besseyi density per seed was significantly different among the eight paddy fields, among rice plant hills in paddy fields, and among panicles in rice plant hills. The proportion of nematode-infested seeds (prevalence) increased and reached an upper limit as the mean density per seed on the panicle scale increased, whereas linear relationships were observed between nematode prevalence and the mean density on plant hill and paddy field scales. Relationships between mean density and mean crowding of nematodes per seed indicated that the nematodes exhibited clumped distribution on each of panicle, plant hill and field scales. Using these relationships, a three-stage sampling plan for estimating nematode density per seed at a specified precision level is presented.


Author(s):  
Yunqiang Xu ◽  
Baolin Su ◽  
Hongqi Wang ◽  
Jingyi He

Abstract. Infiltration is one of the major procedures in water balance research and pollution load estimation in paddy fields. In this study, a new method for indirectly estimating infiltration of paddy fields in situ was proposed and implemented in Taihu Lake basin. Since when there were no rainfall, irrigation and artificial drainage, the water depth variation process of a paddy field is only influenced by evapotranspiration and infiltration (E+F). Firstly, (E+F) was estimated by deciding the steady decreasing rate of water depth; then the evapotranspiration (ET) of the paddy field was calculated by using the crop coefficient method with the recommended FAO-56 Penman-Monteith equation; finally, the infiltration of the paddy field was obtained by subtracting ET from (E+F). Results show that the mean infiltration of the studied paddy field during rice jointing-booting period was 7.41 mm day−1, and the mean vertical infiltration and lateral seepage of the paddy field were 5.46 and 1.95 mm day−1 respectively.


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