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Markus Pahlow - One of the best experts on this subject based on the ideXlab platform.
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Water footprint assessment of Citrus Production in South Africa: A case study of the Lower Sundays River Valley
Journal of Cleaner Production, 2016Co-Authors: Samantha A. Munro, Gavin Fraser, Jen Snowball, Markus PahlowAbstract:Abstract Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary Citrus Production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of Production across all climatic years, followed by soft Citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft Citrus and navels, in that they provided higher net income and more employment hours per m 3 of water in comparison to other Citrus crops. In an average season, lemons generated approximately 39% more income per m 3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for Citrus in the catchment was calculated to be 58.7 Mm 3 for an average season and 89.2 Mm 3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
T.a. Obreza - One of the best experts on this subject based on the ideXlab platform.
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Delineating productivity zones in a Citrus grove using Citrus Production, tree growth and temporally stable soil data
Precision Agriculture, 2011Co-Authors: K. K. Mann, A. W. Schumann, T.a. ObrezaAbstract:The productivity of a Citrus grove with variation in tree growth was mapped to delineate zones of productivity based on several indicator properties. These properties were fruit yield, ultrasonically measured tree canopy volume, normalized difference vegetation index (NDVI), elevation and apparent electrical conductivity (EC_a). The spatial patterns of soil series, soil color and EC_a, and their correspondence with the variation in yield emphasized the importance of variation in the soil in differentiating the productivity of the grove. Citrus fruit yield was positively correlated with canopy volume, NDVI and EC_a, and yield was negatively correlated with elevation. Although all the properties were strongly correlated with yield and were able to explain the productivity of the grove, Citrus tree canopy volume was most strongly correlated ( r = 0.85) with yield, explaining 73% of its variation. Tree canopy volume was used to classify the Citrus grove into five productivity zones termed as ‘very poor’, ‘poor’, ‘medium’, ‘good’ and ‘very good’ zones. The study showed that productivity of Citrus groves can be mapped using various attributes that directly or indirectly affect Citrus Production. The productivity zones identified could be used successfully to plan soil sampling and characterize soil variation in new fields.
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Accumulation and downward transport of phosphorus in florida soils and relationship to water quality
Communications in Soil Science and Plant Analysis, 2001Co-Authors: M. A. Elrashidi, Ashok K. Alva, Y. F. Huang, D. V. Calvert, T.a. ObrezaAbstract:Accumulation of phosphorus (P) for Florida soils under Citrus Production may have an impact on groundwater and nearby streams and lakes. Six extracting solutions including Mehlich3, Bray1, double-acid, ammonium bicarbonate-DTPA (ABDTPA), neutral NH4OAc, and water were used to investigate P accumulation for 44 surface soils. The samples have been collected from old groves in 7 major Citrus Production counties in Florida. The results indicated P accumulation in most soils investigated. Either Mehlich3, Bray1, or double-acid was a good test to evaluate P accumulation. The average amount of P extracted was 121, 97, and 101 mg kg 21 soil for Mehlich3, Bray1,
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Classification of land suitability for Citrus Production using DRAINMOD
Journal of Soil and Water Conservation, 1993Co-Authors: T.a. Obreza, H. Yamataki, Leonard G. PearlstineAbstract:ABSTRACT: Land area used for Citrus (Citrus sinensis L. Osbeck) Production in Southwest Florida has expanded. The location of this expansion is a concern of water use and environmental regulatory agencies. Citrus requires well-drained conditions for optimum growth, but the soils in the region are primarily poorly to very poorly drained with seasonal high water tables. Drainability is the major factor which determines soil suitability for Citrus Production. The objectives of this study were to use the DRAINMOD soil water management/drainage model to 1) simulate water table behavior for artificially-drained flatwoods, slough, and de-pressional soils, 2) determine differences in soil drainability using an index calculated by DRAINMOD, 3) categorize soils as to suitability for Citrus Production, and 4) evaluate the accuracy of the method. Mean SEW30 of depressional soils was higher (indicating lower drainability) than flatwoods or slough soils. Empirical water table data from Citrus groves agreed with this result. Mean SEW30 varied most for the slough soils. Soil suitability for Citrus was ranked in the order flat-woods > sloughs > depressions. Comparison to current Citrus grove locations showed that groves exist on the lands rated high to intermediate in drainability.
Samantha A. Munro - One of the best experts on this subject based on the ideXlab platform.
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Water footprint assessment of Citrus Production in South Africa: A case study of the Lower Sundays River Valley
Journal of Cleaner Production, 2016Co-Authors: Samantha A. Munro, Gavin Fraser, Jen Snowball, Markus PahlowAbstract:Abstract Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary Citrus Production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of Production across all climatic years, followed by soft Citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft Citrus and navels, in that they provided higher net income and more employment hours per m 3 of water in comparison to other Citrus crops. In an average season, lemons generated approximately 39% more income per m 3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for Citrus in the catchment was calculated to be 58.7 Mm 3 for an average season and 89.2 Mm 3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
Kelly T. Morgan - One of the best experts on this subject based on the ideXlab platform.
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Nutrient Management Options for Florida Citrus: A Review of NPK Application and Analytical Methods
Journal of Plant Nutrition, 2015Co-Authors: Davie M. Kadyampakeni, Kelly T. Morgan, Peter Nkedi-kizza, Gabriel N. KasoziAbstract:Citrus Production in Florida is ranked first in the United States. Success of the Citrus industry in the state relies heavily on sound water and nutrient management practices. Recently, Citrus Production has been declining due to the escalating prevalence of the Citrus greening (Liberibacter asiaticus) and canker (Xanthomonas axonopodis) diseases. One option being explored is the manipulation of nutrient management scenarios to increase and enhance tree productivity. The paper presents a review of the management, analytical and application methods of three major nutrients Nitrogen (N), Phosphorus (P), and Potassium (K) on Florida's sandy soils with low organic matter (OM) and high leaching potential due to heavy annual rains (∼1200 mm). The NPK management options for Florida Citrus are compared with those of other Citrus producing regions around the world. Also, the critical tissue and soil nutrient concentrations for optimal and high Citrus Production are discussed. The review paper should provide import...
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Ammonium and Nitrate Distribution in Soil Using Drip and Microsprinkler Irrigation for Citrus Production
Soil Science Society of America Journal, 2014Co-Authors: Davie M. Kadyampakeni, Arnold W Schumann, Kelly T. Morgan, Peter Nkedi-kizza, Kamal MahmoudAbstract:Soil Sci. Soc. Am. J. 78:645–654 doi:10.2136/sssaj2013.07.0319 Received 31 July 2013. *Corresponding author (dkadyampakeni@ufl.edu). © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Ammonium and Nitrate Distribution in Soil Using Drip and Microsprinkler Irrigation for Citrus Production Nutrient Management & Soil & Plant Analysis
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Implementing Advanced Citrus Production Systems in Florida—Early Results
2009Co-Authors: Arnold W Schumann, James P. Syvertsen, Kelly T. MorganAbstract:ADDITIONAL INDEX WORDS. open hydroponics, early Production, water and nutrient effi ciency, Citrus greening The advanced Citrus Production system (ACPS) is a short- to medium-term approach to Citrus water and nutrient management now being evaluated in Florida Citrus groves for sustainable, profi table Citrus Production in the presence of greening and canker diseases. The goal of ACPS is to compress and enhance the Citrus Production cycle so economic payback can be reached in fewer years to offset some of the disease losses. Early economic fruit Production (producing annual net profi ts) should be reached in as little as 3 years, thus achieving early return on investment with its associated economic advantages. The early high yields will be achieved primarily with high-density planting and optimum nutrition and water management using computerized daily fertigation, commonly referred to as “open hydroponics.” Additionally, the Production of an ACPS grove could be sustained by higher tree density (built-in redundancy) since removed diseased trees will simply be compensated for by additional growth of adjacent trees in the high density planting. Two fi eld experiments evaluating ACPS using newly planted and mature trees are described. Descriptions include fi eld plot layouts, automated fertigation system design, equipment selection, irrigation scheduling, monitoring, remote control, fertilizer formulations, and preliminary results from tree measurement and fruit yield. The information will be useful for growers wanting to convert Citrus blocks to ACPS, and will update the research and grower community on the latest Florida-specifi c research results for this intensively managed Production system. The rapid spread of the Citrus greening disease or huanglongbing (HLB), thought to be caused by the bacterium Candidatus Liberibacter asiaticus, to all Florida Citrus producing counties has prompted researchers and growers to evaluate an Advanced Citrus Production System (ACPS) in order to survive the disease and remain competitive until a long-term solution is developed. Citrus canker disease caused by the bacterium Xanthomonas axonopodis pv. citri (Hasse) is also spreading rapidly in Florida. Canker causes fruit drop and results in unsalable fruit; HLB reduces fruit quantity and quality and may kill the Citrus trees over a few years. Current recommendations for HLB management in Florida require the infected trees to be removed as soon as possible after detection, in order to reduce the disease inoculum which can be spread via Asian Citrus psyllid insects (Diaphorina citri) (Brlansky et al., 2009). Therefore, the productive life time of Florida Citrus groves infected with HLB and canker is being severely constrained to perhaps as short as 10 years. Thus, the economic payback period of about 12 years required with conventional management practices will be increasingly diffi cult to achieve. The ACPS is based on the Open Hydroponics System (OHS) already being used for intensive Production of Citrus and
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Citrus Production Systems to Survive Greening: Economic Thresholds
2009Co-Authors: Fritz M. Roka, Arnold W Schumann, Kelly T. Morgan, Ronald P. Muraro, R. Allen Morris, Peter Spyke, William S. Castle, Ed StoverAbstract:ADDITIONAL INDEX WORDS. net present value, yields, planting density, costs, effi ciency Advanced pr oduction systems (APS) and open hydroponic systems (OHS) are proposed strategies for Citrus Production that could increase early Production and sustain Production at higher levels through at least the fi rst 15 years of grove life. Higher tree densities, automated irrigation, and intensive nutrient management will increase costs per acre for establishment and annual cultural care. Estimated cost increases are based on the APS/OHS specifi cations outlined in a companion paper (Morgan et al., 2009). This paper utilizes net present value (NPV) as a framework to evaluate the costs and benefi ts of AP/OH systems. Per acre yields must increase suffi ciently to cover establishment costs. Suffi ciently increasing yields within the fi rst 5 to 7 years of a new grove could make it more likely that an AP/OH system will return positive profi ts over a wider range of fruit prices.
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Citrus Production on the Sandy Soils of Southwest Florida
2006Co-Authors: R. M. Muchovej, H. Yamataki, Thomas A. Obreza, Edward A. Hanlon, Monica Ozores-hampton, Fritz Roka, Sanjay Shukla, Kelly T. MorganAbstract:SL-234, a 7-page illustrated fact sheet by R.M. Muchovej, E.A. Hanlon, T. Obreza, M. Ozores-Hampton, F.M. Roka, S. Shukla, H. Yamataki, and K. Morgan, reviews those challenges facing Citrus growers dealing with soils, water management, and nutrients. The authors describe evolving strategies to efficiently produce Citrus in southwest Florida on variable mineral soils. Published by the UF Department of Soil and Water Science, February 2006.
Willie G. Harris - One of the best experts on this subject based on the ideXlab platform.
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Particulate copper in soils and surface runoff from contaminated sandy soils under Citrus Production.
Environmental science and pollution research international, 2013Co-Authors: Santanu Bakshi, Willie G. HarrisAbstract:Soil contamination by copper (Cu) is a worldwide concern. Laboratory incubation and soil Cu characterization were conducted to examine the effects of external Cu loading and liming on Cu speciation in both bulk soil and particulates of an Alfisol and Spodosol under Citrus Production. Also, drainage water from the sites was evaluated for dissolved and particulate forms of Cu. Soil available Cu estimated by CaCl2, NH4OAc, or Mehlich-3 extraction significantly increased with external Cu loads and decreased with soil pH. Most increases in soil Cu occurred in the exchangeable and oxide-bound fractions. Organically bound Cu was the dominant fraction in both bulk soil and particulates, but more in particulates than bulk soil (P ≤ 0.001). Organically bound Cu was highly correlated with total recoverable Cu (P ≤ 0.01), increased significantly with external Cu loads (P ≤ 0.001), and decreased with soil pH (P ≤ 0.05). Lime addition converted part of Cu from available pools to more stable forms. Organically bound Cu complexes were found to dominate in soil solution or surface runoff. These results indicate that most Cu accumulated in the contaminated soils is highly mobile, and thus may impact Citrus Production and the environment.