scholarly journals Potential of Controlled Irrigation and Drainage for Reducing Nitrogen Emission from Rice Paddies in Southern China

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Guang-cheng Shao ◽  
Ming-hui Wang ◽  
Shuang-en Yu ◽  
Na Liu ◽  
Meng-hua Xiao ◽  
...  
Keyword(s):  
Surface Water ◽  
Southern China ◽  
Rice Paddy ◽  
Growth Stages ◽  
N Losses ◽  
Wetting And Drying ◽  
Nitrogen Emission ◽  
Controlled Irrigation ◽  
Initiation Stage ◽  
Drying Technology

The effect of controlled irrigation and drainage (CID) at different growth stages of rice on nitrogen (N) from rice paddy was studied. Submergence at different stages was imposed in specially designed experimental tanks in 2009 and 2010 based on alternate wetting and drying technology (AWD, the control, CK). Treatments include CID treatment at tiller stage (T1), jointing-booting stage (T2), panicle initiation stage (T3), and milky stage (T4). Results showed that fertilization could significantly increase the concentration ofNH4+-N and TN in surface water but had a little influence onNO3--N. The concentrations ofNH4+-N andNO3--N in surface water increased at first and then decreased after fertilization, while the concentrations ofNH4+-N and TN in groundwater kept on being relatively stable. Compared to CK, CID significantly increased the concentration ofNH4+-N in surface water at four stages. However, it reduced the concentration ofNO3--N. Consistent with the reduction of drainage, CID at four stages could significantly decrease the amount ofNH4+-N andNO3--N losses by runoff in relation to CK.

scholarly journals The Effects of Controlled Drainage on N Concentration and Loss in Paddy Field

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Bin Lu ◽  
Guangcheng Shao ◽  
Shuang’en Yu ◽  
Shiqiang Wu ◽  
Xinghua Xie
Keyword(s):  
Surface Water ◽  
Paddy Field ◽  
Ammonia Nitrogen ◽  
Growth Stages ◽  
Controlled Drainage ◽  
Water Drainage ◽  
N Losses ◽  
Paddy Water ◽  
Waterlogged Condition ◽  
N Concentration

To relieve the situation of the agricultural nonpoint pollution (NPS) in south and east China, paddy field controlled drainage (PFCD) is applied as an important and efficient approach to agricultural water management. A series of PFCD tests at four major growth stages of rice were conducted by use of 18 lysimeters. Concentration of ammonia nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) in surface and subsurface paddy water was observed. The results indicated that the concentration ofNH4+-N andNO3--N in paddy water declined with the persistence of a waterlogged condition. Compared to traditional drainage, PFCD reduced N loss in surface water by 95.6%, 78.7%, 59.6%, and 87.4% at the stage of tillering, jointing-booting, heading-flowering, and milking, respectively. It should be noted that loads of N losses in surface water increased on the fourth day after waterlogging at the jointing-booting and milking stage, and surface water exhibited higher N concentration on the first day after waterlogging at each stage. Therefore, paddy field surface water drainage should be avoided in these periods.

Functional soil organic matter fractions in response to long-term fertilizer management in a double-cropping paddy field of southern China

2021 ◽  
pp. 1-9
Author(s):  
Haiming Tang ◽  
Chao Li ◽  
Lihong Shi ◽  
Li Wen ◽  
Kaikai Cheng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Paddy Field ◽  
Southern China ◽  
Rice Paddy ◽  
Chemical Fertilizer ◽  
Protection Mechanism ◽  
Rice Paddy Field ◽  
Double Cropping

Abstract Soil organic matter (SOM) and its fractions play an important role in maintaining or improving soil quality and soil fertility. Therefore, the effects of a 34-year long-term fertilizer regime on six functional SOM fractions under a double-cropping rice paddy field of southern China were studied in the current paper. The field experiment included four different fertilizer treatments: chemical fertilizer alone (MF), rice straw residue and chemical fertilizer (RF), 30% organic manure and 70% chemical fertilizer (OM) and without fertilizer input as control (CK). The results showed that coarse unprotected particulate organic matter (cPOM), biochemically, physically–biochemically and chemically protected silt-sized fractions (NH-dSilt, NH-μSilt and H-dSilt) were the main carbon (C) storage fractions under long-term fertilization conditions, accounting for 16.7–26.5, 31.1–35.6, 16.2–17.3 and 7.5–8.2% of the total soil organic carbon (SOC) content in paddy soil, respectively. Compared with control, OM treatment increased the SOC content in the cPOM, fine unprotected POM fraction, pure physically protected fraction and physico-chemically protected fractions by 58.9, 106.7, 117.6 and 28.3%, respectively. The largest proportion of SOC to total SOC in the different fractions was biochemically protected, followed by chemically and unprotected, and physically protected were the smallest. These results suggested that a physical protection mechanism plays an important role in stabilizing C of paddy soil. In summary, the results showed that higher functional SOM fractions and physical protection mechanism play an important role in SOM cycling in terms of C sequestration under the double-cropping rice paddy field.

scholarly journals Modelling the effects of changing climate and nitrogen deposition on nitrate dynamics in a Scottish mountain catchment

2009 ◽  
Vol 40 (2-3) ◽  
pp. 153-166 ◽  
Author(s):  
M. N. Futter ◽  
R. C. Helliwell ◽  
M. Hutchins ◽  
J. Aherne
Keyword(s):  
Surface Water ◽  
N Deposition ◽  
Mountain Lake ◽  
N Losses ◽  
Changing Climate ◽  
Warming Climate ◽  
Mountain Catchment ◽  
Constant Rate ◽  
Using Data ◽  
Historical Levels

The effect of changing climate and N deposition on montane ecosystems is a topic of considerable importance. Mountains are vulnerable environments and their ecosystems are often in a delicate balance. An application of the INCA-N model is presented to simulate current-day nitrate dynamics in a Scottish mountain lake and to project the possible future effects of climate change and reductions in N deposition on lake nitrate concentration ([NO3−]). The INCA-N model is calibrated using data from 1996–2006 in an attempt to determine the controls on [NO3−] in Lochnagar and process sensitivities to changing climate. Predictions were sensitive to hydrologic, vegetation-related and in-soil processes. Over the longer term, surface water [NO3−] in this mountain ecosystem is expected to increase. From 2020 to 2100, when N deposition is modelled at a constant rate, warmer temperature exerts a stronger effect on N losses to the lake surface than the N deposition. While the effects of a warming climate are projected to lead to increased surface water [NO3−], concentrations are not projected to either return to, or exceed, historical levels.

scholarly journals Effects of Biochar Amendment on CO2 Emissions from Paddy Fields under Water-Saving Irrigation

2018 ◽  
Vol 15 (11) ◽  
pp. 2580 ◽  
Author(s):  
Shihong Yang ◽  
Zewei Jiang ◽  
Xiao Sun ◽  
Jie Ding ◽  
Junzeng Xu
Keyword(s):  
Co2 Emissions ◽  
Rice Yield ◽  
Rice Paddy ◽  
C Sequestration ◽  
Sensitivity Coefficient ◽  
Water Saving ◽  
Paddy Fields ◽  
Flood Irrigation ◽  
Controlled Irrigation ◽  
Biochar Amendment

The role of carbon pool of biochar as a method of long-term C sequestration in global warming mitigation is unclear. A two-year field study was conducted to investigate the seasonal variations of CO2 emissions from water-saving irrigation paddy fields in response to biochar amendment and irrigation patterns. Three biochar treatments under water-saving irrigation and one biochar treatment under flooding irrigation were studied, and the application rates were 0, 20, 40, and 40 t ha−1 and labeled as CI + NB (controlled irrigation and none biochar added), CI + MB (controlled irrigation and medium biochar added), CI + HB (controlled irrigation and high biochar added), and FI + HB (flood irrigation and high biochar added), respectively. Results showed that biochar application at medium rates (20 t ha−1) decreased CO2 emissions by 1.64–8.83% in rice paddy fields under water-saving irrigation, compared with the non-amendment treatment. However, the CO2 emissions from paddy fields increased by 4.39–5.43% in the CI + HB treatment, compared with CI + NB. Furthermore, the mean CO2 emissions from paddy fields under water-saving irrigation decreased by 2.22% compared with flood irrigation under the same amount of biochar application (40 t ha−1). Biochar amendment increased rice yield and water use efficiency by 9.35–36.30% and 15.1–42.5%, respectively, when combined with water-saving irrigation. The CO2 emissions were reduced in the CI + MB treatment, which then increased rice yield. The CO2 emissions from paddy fields were positively correlated with temperature. The highest value of the temperature sensitivity coefficient (Q10) was derived for the CI + MB treatment. The Q10 was higher under water-saving irrigation compared with flooding irrigation.

scholarly journals Investigation of pesticide residues in surface water in some areas of agricultural production at Ho Chi Minh city

2013 ◽  
Vol 16 (3) ◽  
pp. 106-119
Author(s):  
Phu Ly Sy Nguyen ◽  
Nguyen Duc Do ◽  
Hien Thi To
Keyword(s):  
Surface Water ◽  
Pesticide Residues ◽  
Agricultural Production ◽  
Chromatographic Method ◽  
Organophosphorus Pesticides ◽  
Ho Chi Minh City ◽  
Growth Stages ◽  
High Concentrations ◽  
Gas Chromatographic Method ◽  
Agricultural Areas

Residual levels of organochlorine and organophosphorus pesticides in surface water in some agricultural areas at Ho Chi Minh City were investigated in 2012. Four organophosphorus pesticides including Malathion, Parathion, Ethion and Trithion and seven organochlorine pesticides including Alpha - HCH, beta-HCH, gammaHCH, aldrin, Heptachlor – epoxide, AlphaEndosulfan and Endosulfan-sulfate were determined in the surface water in four dicstricts : Binh Chanh, Hoc Mon, Cu Chi and Binh Tan using gas chromatographic method with electron capture detector (GCECD). The results showed that residues of pesticide were found with high concentrations in surface water in agricultural areas and pesticide residues changed depending on growth stages of crops. The concentration and distribution of pesticides were different in the water samples at different sites. Residues of pesticides such as Parathion, Ethion and Trithion were detected in surface water although these chemicals had been banned.

scholarly journals Pinus massoniana Introgression Hybrids Display Differential Expression of Reproductive Genes

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 230 ◽  
Author(s):  
Jiaxing Mo ◽  
Jin Xu ◽  
Yuting Cao ◽  
Liwei Yang ◽  
Tongming Yin ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Southern China ◽  
Pinus Massoniana ◽  
Growth Stages ◽  
Reproductive Process ◽  
Clusters Of Orthologous Groups ◽  
Ripening Rate ◽  
Pine Cones ◽  
Insight Into ◽  
Gene Expression Levels

Pinus massoniana and P. hwangshanensis are two conifer species located in southern China, which are of both economic and ornamental value. Around the middle and lower reaches of the Yangtze River, P. massoniana occurs mainly at altitudes below 700 m, while P. hwangshanensis can be found above 900 m. At altitudes where the distribution of both pines overlaps, a natural introgression hybrid exists, which we will further refer to as the Z pine. This pine has a morphological character that shares attributes of both P. massoniana and P. hwangshanensis. However, compared to the other two pines, its reproductive structure, the pinecone, has an ultra-low ripening rate with seeds that germinate poorly. In this study, we aimed to find the reason for the impaired cone maturation by comparing transcriptome libraries of P. massoniana and Z pine cones at seven successive growth stages. After sequencing and assembly, we obtained unigenes and then annotated them against NCBI’s non-redundant nucleotide and protein sequences, Swiss-Prot, Clusters of Orthologous Groups, Gene Ontology and KEGG Orthology databases. Gene expression levels were estimated and differentially expressed genes (DEGs) of the two pines were mined and analyzed. We found that several of them indeed relate to reproductive process. At every growth stage, these genes are expressed at a higher level in P. massoniana than in the Z pine. These data provide insight into understanding which molecular mechanisms are altered between P. massoniana and the Z pine that might cause changes in the reproductive process.

scholarly journals The Optimal Image Date Selection for Evaluating Cultivated Land Quality Based on Gaofen-1 Images

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4937 ◽  
Author(s):  
Ziqing Xia ◽  
Yiping Peng ◽  
Shanshan Liu ◽  
Zhenhua Liu ◽  
Guangxing Wang ◽  
...  
Keyword(s):  
Regression Models ◽  
Vegetation Index ◽  
Southern China ◽  
Regional Scale ◽  
Growth Stages ◽  
Maturity Stage ◽  
Cultivated Land ◽  
Flowering Stage ◽  
Area Index ◽  
Land Quality

This study proposes a method for determining the optimal image date to improve the evaluation of cultivated land quality (CLQ). Five vegetation indices: leaf area index (LAI), difference vegetation index (DVI), enhanced vegetation index (EVI), normalized difference vegetation index (NDVI), and ratio vegetation index (RVI) are first retrieved using the PROSAIL model and Gaofen-1 (GF-1) images. The indices are then introduced into four regression models at different growth stages for assessing CLQ. The optimal image date of CLQ evaluation is finally determined according to the root mean square error (RMSE). This method is tested and validated in a rice growth area of Southern China based on 115 sample plots and five GF-1 images acquired at the tillering, jointing, booting, heading to flowering, and milk ripe and maturity stage of rice in 2015, respectively. The results show that the RMSEs between the measured and estimated CLQ from four vegetation index-based regression models at the heading to flowering stage are smaller than those at the other growth stages, indicating that the image date corresponding with the heading to flowering stage is optimal for CLQ evaluation. Compared with other vegetation index-based models, the LAI-based logarithm model provides the most accurate estimates of CLQ. The optimal model is also driven using the GF-1 image at the heading to flowering stage to map CLQ of the study area, leading to a relative RMSE of 14.09% at the regional scale. This further implies that the heading to flowering stage is the optimal image time for evaluating CLQ. This study is the first effort to provide an applicable method of selecting the optimal image date to improve the estimation of CLQ and thus advanced the literature in this field.

Effect of silicon at panicle initiation on the growth of rice (Var. ADT-36) plants at different growth stages

2002 ◽  
Vol 50 (2) ◽  
pp. 179-184
Author(s):  
P. M. Arthanari ◽  
P. Gnanamoorthy ◽  
S. Ramasamy
Keyword(s):  
Tamil Nadu ◽  
Dry Matter ◽  
Field Experiments ◽  
Dry Matter Production ◽  
Growth Stages ◽  
Maturity Stage ◽  
Maturity Stages ◽  
Matter Production ◽  
Initiation Stage ◽  
Different Growth Stages

Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India during the Rabi (November 1997-March 1998) and Kharif (July 1998-November 1998) seasons to identify the effect of silicon at panicle initiation on the growth of rice plant (Variety ADT-36) at different growth stages. Furnace slag was applied as a silicon source at 2 t/ha at the panicle initiation stage along with other nutrients. The dry matter production was recorded at the active tillering, panicle initiation, booting, flowering, one week after flowering and maturity stages in both the seasons. The total dry matter production was greater in the Kharif season than in the Rabi season. The application of slag at the panicle initiation stage along with N and K at the flowering stage had a significant influence over the dry matter production. A similar trend was observed in both the seasons. The silicon uptake was recorded at the panicle initiation and maturity stages. About 30-40% of the silicon absorbed during the early stages and the maturity stage was present in the shoot, whereas 20-30 % of the silicon absorbed during the maturity stages was present in the leaf blades. Based on the results, it is concluded that the supply of silicon during the panicle initiation stage is most important for plant growth.

scholarly journals Research on Land Surface Thermal-Hydrologic Exchange in Southern China under Future Climate and Land Cover Scenarios

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Jianwu Yan ◽  
Baozhang Chen ◽  
Min Feng ◽  
John L. Innes ◽  
Guangyu Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Land Cover ◽  
Land Cover Change ◽  
Land Surface ◽  
Southern China ◽  
Future Climate ◽  
Land Surface Water ◽  
Hydrologic Exchange ◽  
Heat Exchanges

Climate change inevitably leads to changes in hydrothermal circulation. However, thermal-hydrologic exchanging caused by land cover change has also undergone ineligible changes. Therefore, studying the comprehensive effects of climate and land cover changes on land surface water and heat exchanges enables us to well understand the formation mechanism of regional climate and predict climate change with fewer uncertainties. This study investigated the land surface thermal-hydrologic exchange across southern China for the next 40 years using a land surface model (ecosystem-atmosphere simulation scheme (EASS)). Our findings are summarized as follows. (i) Spatiotemporal variation patterns of sensible heat flux (H) and evapotranspiration (ET) under the land cover scenarios (A2a or B2a) and climate change scenario (A1B) are unanimous. (ii) BothHand ET take on a single peak pattern, and the peak occurs in June or July. (iii) Based on the regional interannual variability analysis,Hdisplays a downward trend (10%) and ET presents an increasing trend (15%). (iv) The annual averageHand ET would, respectively, increase and decrease by about 10% when woodland converts to the cultivated land. Through this study, we recognize that land surface water and heat exchanges are affected greatly by the future climate change as well as land cover change.

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