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Site-Specific Nitrogen management in Dry Direct-Seeded Rice Using Chlorophyll Meter and Leaf Colour Chart

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Pedosphere 2015年第1期25卷 72-81页

作者： Ali Mohamed ALI Harmit Singh THIND Sandeep SHARMA YADVINDER-SINGH Department of soil Science Punjab Agricultural University Department of soil fertility and Microbiology Desert Research Centre

The need to maintain high rice yields and improve fertilizer nitrogen(N)-use efficiency has fueled the use of tools such as leaf colour chart(LCC) and chlorophyll meter(SPAD meter) in managing fertilizer N based on colour of the leaf. Field experiments were conducted during 2011 to 2013 at Ludhiana, India to assess the need for basal N application and to establish critical threshold values of leaf greenness as measured by LCC and SPAD meter for formulating strategies for in-season management of fertilizer N in dry direct-seeded rice(DDSR). Avoiding application of N at sowing did not adversely affect rice grain yield, indicating that basal N application in DDSR was not necessary and might lead to reduced N-use efficiency. Monitoring N uptake rate during the growing season of DDSR suggested that N uptake rate peaked at the two growth stages: maximum tillering(42 to 56 days after sowing(DAS))and panicle initiation stages(70 to 84 DAS). Using the Cate-Nelson procedure, critical LCC and SPAD meter values for fertilizer N application worked out to be 4 and 37, respectively. Real-time fertilizer N management strategy based on applying 30 kg N ha-1whenever SPAD meter or LCC readings fell below the critical values maintained optimum rice yields along with higher N-use efficiency than that observed by following blanket recommendation for fertilizer N in the region. The fixed-time variable-dose strategy consisted of applying prescriptive doses of 20 kg N ha-1at 14 DAS and 30 kg N ha-1at 28 DAS and corrective doses of 30, 40 or 50 kg N ha-1at 49 and 70 DAS depending upon LCC shade to be ≥ 4, 4–3.5, or < 3.5 and SPAD meter readings to be ≥ 40, 40–35, or< 35, respectively. This strategy also resulted in optimal rice yield along with higher N-use efficiency as compared to the blanket recommendation. This study revealed that in DDSR, fertilizer N could be managed more efficiently using the tools of LCC and SPAD meter than the current blanket recommendation.

关键词： basal N application critical value grain yield leaf greenness N-use efficiency

Wheat grain yield and nitrogen uptake prediction using atLeaf and GreenSeeker portable optical sensors at jointing growth stage

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Information Processing in Agriculture 2020年第3期7卷 375-383页

作者： Ali M.Ali S.M.Ibrahim Bijay-Singh Department of soil fertility and Microbiology Desert Research CenterCairo 11753Egypt Department of soil Science Punjab Agricultural UniversityLudhiana 141004India

Rapid acquisition of information about nitrogen(N)uptake and grain yield is an essential step in making site-specific in-season fertilizer N management *** objective of this study was to quantify and validate the relationships between N uptake and grain yield of wheat using in-season measurements with atLeaf chlorophyll meter and GreenSeeker optical sensor at Feekes 6 growth stage(jointing stage)of *** relationships were developed using data generated from experiments with multi-rate fertilizer N treatments and conducted in two consecutive wheat seasons(2017/2018 and 2018/2019)at two locations in the western Nile Delta of Egypt.A power function based on atLeaf measurement at Feekes 6 stage of wheat could explain 55.3%and 53.3%variations in the N uptake at this stage and grain yield at maturity,*** with GreenSeeker were related with N uptake and yield of wheat through exponential function and could explain 68.5%and 60.6%of the variation in N uptake and grain yield,*** developed models were validated on an independent data set from another field experiment on *** normalized root mean square error for the relation between atLeaf measurements and N uptake and grain yield were fair,whereas the fits were good for measurements with *** study reveals that atLeaf chlorophyll meter and GreenSeeker optical sensor can be successfully used for establishing site-specific N management strategies in wheat.

关键词： N uptake Grain yield Wheat atLeaf sensor GreenSeeker sensor

The use of woods-run chips in filter socks to control erosion and sedimentation during petroleum development in the Appalachian Basin

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International Journal of Sediment Research 2019年第6期34卷 608-615页

作者： Shawn T.Grushecky Louis M.McDonald Lawrence Osborn West Virginia University Davis College of Agriculture Natural Resources and Design School of Natural Resources Appalachian Hardwood Center at West Virginia University School of Natural Resources Energy Land Management 3. Division of Plant and Soil SciencesEnvironmental Soil Chemistry and Soil Fertility

Filter socks frequently are used for erosion and sediment perimeter control during oil and gas development activities in the Appalachian Basin of the United *** specify the use of composted wood material for sock *** specification,as opposed to non-composted or fresh wood chips(woods-run),has created inefficiencies during well site *** than use fresh wood chips created during site construction,composted chips must be procured and used as filter sock media for erosion and sedimentation *** woods-run chips could be used as filter sock media instead of composted chips,there could be a significant reduction in energy/capital costs,truck traffic,and disposal *** primary objective of this research project was to compare the effectiveness of woodsrun material versus traditionally composted wood chips in controlling sediment transport as well as other chemical and physical parameters in a laboratory *** significant differences in pH(5.96 versus 6.02) or conductivity(0.029 dS/m versus 0.035 dS/m) were found in sediment laden water filtered through woods-run versus composted chips,***,chip particle sizes were outside the allowable limits for composted sock media,and moisture content also was outside the specified limits for woods-run ***(NO) concentrations were significantly higher in woods-run,while phosphorus(P) and potassium(K) concentrations were greater in composted chips;however none of the N,P,or K concentrations were above the regulatory ***,no difference in the filtering efficiency or time was found between woods-run and composted *** laboratory results indicate that current regulations allowing the use of woods-run chips in all but the highest quality watersheds is justified.

关键词： BMP Filter socks Petroleum exploration Marcellus shale Wood chips

Root-associated(rhizosphere and endosphere) microbiomes of the Miscanthus sinensis and their response to the heavy metal contamination

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Journal of Environmental Sciences 2021年第6期33卷 387-398页

作者： Xiaoxu Sun Benru Song Rui Xu Miaomiao Zhang Pin Gao Hanzhi Lin Weimin Sun National-Regional Joint Engineering Research Center for soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China

The plant root-associated microbiomes, including both the rhizosphere and the root endosphere microbial community, are considered as a critical extension of the plant genome. Comparing to the well-studied rhizosphere microbiome, the understanding of the root endophytic microbiome is still in its infancy. Miscanthus sinensis is a pioneering plant that could thrive on metal contaminated lands and holds the potential for phytoremediation applications. Characterizing its root-associated microbiome, especially the root endophytic microbiome, could provide pivotal knowledge for phytoremediation of mine tailings. In the current study, M. sinensis residing in two Pb/Zn tailings and one uncontaminated site were collected. The results demonstrated that the metal contaminant fractions exposed strong impacts on the microbial community structures. Their influences on the microbial community, however, gradually decreases from the bulk soil through the rhizosphere soil and finally to the endosphere, which resulting in distinct root endophytic microbial community structures compared to both the bulk and rhizosphere soil. Diverse members affiliated with the order Rhizobiales was identified as the core microbiome residing in the root of M. sinensis. In addition, enrichment of plant-growth promoting functions within the root endosphere were predicted, suggesting the root endophytes may provide critical services to the host plant. The current study provides new insights into taxonomy and potential functions of the root-associated microbiomes of the pioneer plant, M. sinensis, which may facilitate future phytoremediation practices.

关键词： Tailing Miscanthus sinensis Root endosphere Metal(loid)s contamination

Bacterial Community Structure and Diversity in a Black soil as Affected by Long-Term Fertilization

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Pedosphere 2008年第5期18卷 582-592页

作者： WEI Dan YANG Qian ZHANG Jun-Zheng WANG Shuang CHEN Xue-Li ZHANG Xi-Lin LI Wei-Qun Harbin Institute of Technology Harbin 150001 （China）. The Institute of soil fertility and Environmental Sources Heilongjiang Academy of Agricultural Sciences Harbin 150086（China）

Black soil （Mollisol） is one of the main soil types in northeastern China. Biolog and polymerase chain reactiondenaturing gradient gel electrophoresis （PCR-DGGE） methods were used to examine the influence of various fertilizer combinations on the structure and function of the bacterial community in a black soil collected from Harbin, Heilongjiang Province. Biolog results showed that substrate richness and catabolic diversity of the soil bacterial community were the greatest in the chemical fertilizer and chemical fertilizer＋manure treatments. The metabolic ability of the bacterial community in the manure treatment was similar to the control. DGGE fingerprinting indicated similarity in the distribution of most 16S rDNA bands among all treatments, suggesting that microorganisms with those bands were stable and not influenced by fertilization. However, chemical fertilizer increased the diversity of soil bacterial community. Principal com- ponent analysis of Biolog and DGGE data revealed that the structure and function of the bacterial community were similar in the control and manure treatments, suggesting that the application of manure increased the soil microbial population, but had no effect on the bacterial community structure. Catabolic function was similar in the chemical fertilizer and chemical fertilizer＋manure treatments, but the composition structure of the soil microbes differed between them. The use of chemical fertilizers could result in a decline in the catabolic activity of fast-growing or eutrophic bacteria.

关键词： bacteria community black soil chemical fertilizer diversity manure

Experimental determination of sediment transport capacity of rill flow over sandified loess slope

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International soil and Water Conservation Research 2023年第2期11卷 301-310页

作者： Ren Feng Jiacun Chen Zhenyue Xie Dingqiang Li Zaijian Yuan National-Regional Joint Engineering Research Center for soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou510650China Meizhou International Institute of soil and Water Conservation Meizhou514000China

Rill erosion is affected by the sand particle content in soil,especially in the wind and water erosion transition region of the Loess *** sediment transport capacity(STC)is a key parameter in rill erosion research,assessing the impact of aeolian sand intrusion on the STC of rill flow is of importance for a better understanding of rill *** study aimed to assess the effect of aeolian sand intrusion on the STC on sandified loess slopes,with typical slopes and flow discharges,using a flume system which consisting of a sediment-feeding and a sediment-supply/settlement *** sediment feeding flume was jointed by 10°higher than that of the sediment measurement flume *** flow discharges(2,4,and 8 L min^(-1))and four slope gradients(5°,10°,15°,and 25°)were used to represent the natural hydrological conditions under three intrusion rates(SIR)of aeolian sands(10%,20%,and 50%).The results show that STC increased with slope gradient and flow discharge,and the relationship between the STC and the SIR was significantly affected by the slope gradient;the STCs decreased with the SIR on a slope of 5°but increased with the SIR on steep slopes of 15°-25°,implying a significant impact of slope gradient on the relationship between SIR and *** SIR of 50%resulted in the highest sediment concentration nearly 1200 kg m^(-3)on slopes of 25°.On sandified loess slopes of 10%,20%,and 50%SIR,the STC were about 30%,46%,and 57%higher than on loess slopes,indicating an increased erosion rate by sand particle intrusion into loess *** results highlight the impact of sand intrusion on STC of rill flow and provide deeper insights into the soil loss process on the sandified loess slope.

关键词： Sand intrusion Loess soil Rill flow Transport capacity

Preliminary investigation on rodent–ectoparasite associations in the highlands of Tigray, Northern Ethiopia:implications for potential zoonoses

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Integrative Zoology 2011年第4期6卷 366-374页

作者： Meheretu YONAS Kiros WELEGERIMA Anne LAUDISOIT Hans BAUER Kindeya GEBREHIWOT Seppe DECKERS Abdul KATAKWEBA Rhodes MAKUNDI Herwig LEIRS Department of Biology Mekelle UniversityMekelleEthiopia Evolutionary Ecology Group University of AntwerpBelgium Institute of Integrative Biology University of LiverpoolBiosciencesLiverpoolUK Institutional University Cooperation project Mekelle UniversityMekelleEthiopia Department of Land Resources management and Environmental Protection Mekelle UniversityMekelleEthiopia Division of soil and Water management K.U.LeuvenHeverleeBelgium Pest management Center Sokoine University of AgricultureMorogoroTanzania Department of integrated Pest management University of AarhusSlagelseDenmark

We studied associations between rodents and their arthropod ectoparasites in crop fields and household compounds in the highlands of Tigray,Northern *** infestation indices,such as percent infestation,mean abundance,prevalence and host preferences,were calculated for each *** total,172 rodents from crop fields and 97 from household compounds were *** species and numbers trapped from the crop fields and household compounds were Mastomys awashensis(Lavrenchenko,Likhnova&Baskevich,1998)(88 and 44),Arvicanthis dembeensis(Ruppel,1842)(63 and 37)and Acomys sp.(21 and 16),respectively.A total of 558 insects and acarids(belonging to 11 taxa)were recovered from the rodents trapped in the crop fields,and 296 insects and acarid(belonging to 6 taxa)from the rodents trapped in the household *** 66%of the rodents trapped from the crop fields and 47%of those trapped from the household compounds were infested with *** sp.(64.9%)and Xenopsylla sp.(20.6%)comprised the highest proportion of the ectoparasites recovered in the crop fields,and the same ectoparasites,but in reverse order,comprised the highest proportions in the household compounds(Xenopsylla[50.3%]and Laelaps sp.[29%]).Our study revealed that crop fields and household compounds in the highlands share similar rodents and several ***,at least 1 of the rodent species and some of the ectoparasites identified in this study were reported to have posed medical and veterinary threats in other parts of Ethiopia and neighboring countries.

关键词： ectoparasites Northern Ethiopia rodents zoonoses

soil and Land Suitability Assessment for Rice Cultivation at Tono Irrigation Area in the Upper East Region, Ghana

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Open Journal of Applied Sciences 2021年第11期11卷 1230-1239页

作者： Prince M. Gyekye Charles Y. F. Domozoro Mohammed Musah Felix O. Ababio Adams Sadick soil Survey GIS and Mapping CSIR-Soil Research Institute Accra Ghana Natural Resources management CSIR-Animal Research Institute Accra Ghana soil fertility and Nutrition CSIR-Soil Research Institute Kwadaso Ghana Directorate/soil fertility CSIR-Soil Research Institute Accra Ghana Analytical Services Laboratory CSIR-Soil Research Institute Kwadaso Ghana

Agriculture is one of the livelihood supports for the people of Upper East Region of Ghana. soil evaluation research was conducted at Tono Irrigation Scheme to assess soil and land suitability for rice cultivation in the irrigable area of Tono Irrigation Scheme. A total of eleven (11) soil samples were collected and analysed for their chemical and physical properties. Based on field observation and criteria for soil suitability assessment, the different soil types that were identified were classified at the series level based on their position, parent material and the observed physical characteristics. The results indicated that the pH of the soils was within the acceptable range for crop production;however, the overall fertility level of the soils was very low. Physically, the upland soils were well to moderately well-drained, consisting of coarse-grained sandy loams topsoil overlying similar sandy loams and sandy clay loams at depth. They included Leptosols and Lixisols. The soils of the Scheme under lowlands and valley bottom sites, however, included Eutric Gleysol, Calsic Vertisol, Eutric Fluvisol and Eutric Plinthosol, which were heavily textured and relatively poor drained, or medium-textured and moderately to imperfectly well-drained. They showed a low to a very low rate of water percolation losses, which is good for the current farming system of cropping rice within the lowlands and valley bottom sites of the Scheme.

关键词： soil Classification Lowland Upland Irrigation Valley Bottom

Chromium transformation driven by iron redox cycling in basalt-derived paddy soil with high geological background values

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Journal of Environmental Sciences 2023年第3期125卷 470-479页

作者： Ke Zhang Yang Yang Wenting Chi Guojun Chen Yanhong Du Shiwen Hu Fangbai Li Tongxu Liu Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China National-Regional Joint Engineering Research Center for soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China University of Chinese Academy of Sciences Beijing 100049China

The flooding and drainage of paddy fields has great effects on the transformation of heavy metals, however, the transformation of Cr in basalt-derived paddy soil with high geological background values was less recognized. The typical basalt-derived paddy soil was incubated under alternating redox conditions. The Cr fractions and the dynamics of Fe/N/S/C were examined. The HCl-extractable Cr increased under anaerobic condition and then decreased during aerobic stage. The UV-vis spectra of the supernatant showed that amounts of colloids were released under anaerobic condition, and then re-aggregated during aerobic phase. The scanning transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS) revealed that Fe oxides were reduced and became dispersed during anaerobic stage, whereas Fe(Ⅱ) was oxidized and recrystallized under aerobic condition. Based on these results, a kinetic model was established to further distinguish the relationship between the transformation of Cr and Fe. During anaerobic phase, the reduction of Fe(Ⅲ) oxides not only directly released the structurally bound Cr, but also enhanced the breakdown of soil aggregation and dissolution of organic matter causing indirect mobilization of Cr. During aerobic phase, the oxidation of Fe (Ⅱ) and further recrystallization of newly formed Fe(Ⅲ) oxides might induce the re-aggregation of soil colloids and further incorporation of Cr. In addition,the kinetic model of Cr and Fe transformation was further verified in the pot *** model-based findings demonstrated that the Cr transformation in the basalt-derived paddy soil with high geological background values was highly driven by redox sensitive iron cycling.

关键词： Chromium Paddy soil Iron oxides Redox High geological background