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12 results on '"Pachas, Anibal Nahuel"'

1. Grazing management for soil carbon in Australia: A review

Author

McDonald, Sarah E., Badgery, Warwick, Clarendon, Simon, Orgill, Susan, Sinclair, Katrina, Meyer, Rachelle, Butchart, Dominique Bowen, Eckard, Richard, Rowlings, David, Grace, Peter, Doran-Browne, Natalie, Harden, Steven, Macdonald, Ainslie, Wellington, Michael, Pachas, Anibal Nahuel Alejandro, Eisner, Rowan, Amidy, Martin, and Harrison, Matthew Tom

Published
2023
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3. Drone-Based Environmental Monitoring and Image Processing Approaches for Resource Estimates of Private Native Forest

Author

Srivastava, Sanjeev Kumar, Seng, Kah Phooi, Ang, Li Minn, Pachas, Anibal Nahuel A., Lewis, Tom, Srivastava, Sanjeev Kumar, Seng, Kah Phooi, Ang, Li Minn, Pachas, Anibal Nahuel A., and Lewis, Tom

Abstract

This paper investigated the utility of drone-based environmental monitoring to assist with forest inventory in Queensland private native forests (PNF). The research aimed to build capabilities to carry out forest inventory more efficiently without the need to rely on laborious field assessments. The use of drone-derived images and the subsequent application of digital photogrammetry to obtain information about PNFs are underinvestigated in southeast Queensland vegetation types. In this study, we used image processing to separate individual trees and digital photogrammetry to derive a canopy height model (CHM). The study was supported with tree height data collected in the field for one site. The paper addressed the research question “How well do drone-derived point clouds estimate the height of trees in PNF ecosystems?” The study indicated that a drone with a basic RGB camera can estimate tree height with good confidence. The results can potentially be applied across multiple land tenures and similar forest types. This informs the development of drone-based and remote-sensing image-processing methods, which will lead to improved forest inventories, thereby providing forest managers with recent, accurate, and efficient information on forest resources.

Published
2022

7. Fire Regime Has a Greater Impact Than Selective Timber Harvesting on Vegetation in a Sub-Tropical Australian Eucalypt Forest

Author

Lewis, Tom, Menzies, Tracey, Pachas, Anibal Nahuel, Lewis, Tom, Menzies, Tracey, and Pachas, Anibal Nahuel

Abstract

We compared selectively harvested and unharvested areas located among treatments of annual burning since 1952, triennial burning since 1973 and an area that had received no prescribed burning, but with a single wildfire in 2006 (one fire in 72 years), in a dry sclerophyll eucalypt forest, south-eastern Queensland, Australia. Historic fire regime, rather than low-intensity, selective timber harvesting (17% to 37% live tree basal area removed) had a greater impact on a range of vegetation and soil attributes. Plant taxa composition was influenced more by historic fire regime than recent harvesting; of the 25.5% of the variation in taxa composition explained, fire treatments alone accounted for 96.4% of the explained variation and harvesting alone accounted for just 4.8%. Selective harvesting of timber had a predictable influence associated with removal of tree cover and physical impacts associated with extraction of logs. In harvested areas there were increases (p < 0.05) in bare-ground cover and in coarse woody debris volumes and decreases in understorey vegetation height, particularly where woody understorey was present. However, overall, the combined effects of timber harvesting and fire regime were relatively minor. These sub-tropical dry eucalypt forests appear to be resilient to the impacts of combined, but low-intensity disturbances. View Full-Text

Published
2021

8. Species-Specific Allometric Equations for Predicting Belowground Root Biomass in Plantations: Case Study of Spotted Gums (Corymbia citriodora subspecies variegata) in Queensland

Author

Huynh, Trinh, Applegate, Grahame, Lewis, Tom, Pachas, Anibal Nahuel A., Hunt, Mark A., Bristow, Mila, Lee, David J., Huynh, Trinh, Applegate, Grahame, Lewis, Tom, Pachas, Anibal Nahuel A., Hunt, Mark A., Bristow, Mila, and Lee, David J.

Abstract

Spotted gum (Corymbia citriodora spp. variegata; CCV) has been widely planted, has a wide natural distribution, and is the most important commercially harvested hardwood species in Queensland, Australia. It has a great capacity to sequester carbon, thus reducing the impact of CO2 emissions on climate. Belowground root biomass (BGB) plays an important role as a carbon sink in terrestrial ecosystems. To explore the potential of biomass and carbon accumulation belowground, we developed and validated models for CCV plantations in Queensland. The roots of twenty-three individual trees (size range 11.8–42.0 cm diameter at breast height) from three sites were excavated to a 1-m depth and were weighed to obtain BGB. Weighted nonlinear regression models were most reliable for estimating BGB. To evaluate the candidate models, the data set was cross-validated with 70% of the data used for training and 30% of the data used for testing. The cross-validation process was repeated 23 times and the validation of the models were averaged over 23 iterations. The best model for predicting spotted gum BGB was based on a single parameter, with the diameter at breast height (D) as an independent variable. The best equation BGB = 0.02933 × D2.5805 had an adjusted R2 of 0.854 and a mean absolute percentage error of 0.090%. This equation was tested against published BGB equations; the findings from this are discussed. Our equation is recommended to allow improved estimates of BGB for this species.

Published
2021

10. Leucaena feeding systems in Argentina. II. Current uses and future research priorities = Sistemas de alimentación con leucaena en Argentina: II. Situación actual y prioridades de investigación futura

Author

Radrizzani Bonadeo, Alejandro, Pachas, Anibal Nahuel, Gandara, Luis, Nenning, Fernando Ramon, and Pueyo, Joaquin Dante

Subjects
Silvopastoral Systems, Research, Investigación, Argentina, Alimentación de los Animales, Sistemas Silvopascícolas, Animal Feeding, Ganado de Carne, Leucaena leucocephala, Beef Cattle
Abstract

This paper presents the current status of Leucaena leucocephala (leucaena) feeding systems and proposes research priorities for leucaena development in Argentina. Although research on leucaena as forage for cattle production began in the late 1960s, it was not widely adopted until 2010 (5 decades later). The recent adoption is related to the incorporation of the ‘Australian technology package’, previously adapted for use by farmers in the neighboring region of the Paraguayan Chaco. In June 2018, we surveyed 8 properties with about 2,400 ha of leucaena in silvopastoral systems for beef cattle production in the Argentinean Chaco region, as well as 10 smallholder farms with about 10 ha of leucaena protein banks for dairy cattle in the northeast of Argentina. In the silvopastoral systems, leucaena condition was excellent on most properties in the 750‒1,350 mm/year rainfall zone and low/poor on only 1 farm due to low rainfall (600 mm/year). In protein banks, leucaena condition was excellent or good on 6 of the properties and low/poor on the remaining 4, attributed to ingress of weeds and/or overgrazing. Grass condition was good in most of the systems but was low/poor in 2 silvopastoral systems due to very high stocking rates imposed to restrict leucaena height. Although there is high potential for leucaena development in Argentina, expansion should take place carefully with leucaena planted only on areas suitable for successful establishment, and using appropriate management practices to reduce establishment failures and costs, restrict leucaena height, enhance grass persistence, improve grazing strategies and manage mimosine toxicity problems. Este trabajo presenta la situación actual de sistemas de producción ganadera que utilizan Leucaena leucocephala (leucaena) en Argentina. Aunque la investigación en leucaena como forrajera para la producción ganadera comenzó a fines de los 60s, la especie fue adoptada en mayor escala recién a partir del 2010 (5 décadas después). Esta reciente adopción se relaciona con la incorporación del ‘paquete tecnológico australiano’, también adoptado y adaptado por productores de la región vecina del Chaco paraguayo. En junio de 2018 identificamos y avaluamos unas 2,400 ha (8 propiedades) de leucaena en sistemas silvopastoriles de bovinos de carne en la región del Chaco argentino. Al mismo tiempo, evaluamos unas 10 ha (10 pequeños productores) con leucaena como bancos de proteína para vacas lecheras en el noreste argentino. En los sistemas silvopastoriles, la condición de leucaena fue calificada como excelente en la mayoría de los campos ubicados en áreas con precipitación anual de 750 a 1,350 mm/año, a excepción de una propiedad con mala condición de leucaena asociada a la baja precipitación (600 mm/año). En los bancos de proteína, la condición de leucaena fue valorada como excelente y buena en el 60% de los campos y fue mala en el 40% restante, atribuida a la falta de control de malezas y/o sobrepastoreo. La condición de las gramíneas fue buena en la mayoría de los sistemas, pero fue mala en 2 de los sistemas silvopastoriles donde se aplicó alta presión de pastoreo para evitar el crecimiento excesivo de leucaena. Si bien existe un gran potencial para el desarrollo de leucaena en Argentina, la expansión debe hacerse cuidadosamente, seleccionando solo aquellos sitios apropiados para su crecimiento, y aplicando prácticas de manejo adecuadas para reducir riesgos y costos de implantación, restringir la altura excesiva, aumentar la persistencia de las gramíneas, mejorar las estrategias de pastoreo y manejar los problemas de toxicidad por mimosina. Instituto de Investigación Animal del Chaco Semiárido Fil: Radrizzani Bonadeo, Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Animal del Chaco Semiárido; Argentina. Fil: Pachas, Anibal Nahuel. The University of Queensland. School of Agriculture and Food Sciences; Australia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; Argentina. Fil: Gandara, Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Corrientes; Argentina Fil: Nenning, Fernando Ramon. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria El Colorado. Agencia De Extensión Rural Formosa; Argentina Fil: Pueyo, Joaquin Dante. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria El Colorado; Argentina

Published
2019

11. Leucaena feeding systems in Argentina. I. Five decades of research and limitations for adoption = Sistemas de alimentación con leucaena en Argentina: I. Cinco décadas de investigación y limitantes para su adopción

Author

Radrizzani Bonadeo, Alejandro, Pachas, Anibal Nahuel, Gandara, Luis, Goldfarb, Maria Cristina, Perticari, Alejandro, Lacorte, Santiago María, and Pueyo, Joaquin Dante

Subjects
Forage, Research, Investigación, Argentina, Alimentación de los Animales, Animal Feeding, Forrajes, Ganado de Carne, Leucaena leucocephala, Beef Cattle
Abstract

This review describes the history of research in Leucaena leucocephala (leucaena) feeding systems carried out by the National Institute of Agricultural Technology (INTA) over the last 5 decades and discusses the main limitations resulting in poor adoption in Argentina. Leucaena was introduced in the subtropical region of the north of the country in the late 1960s and early 1970s. Since then, INTA has conducted research to evaluate forage and animal productivity, leucaena accessions, rhizobial strains, contribution to soil carbon and total nitrogen and density effects on competition and other ecosystem interactions in silvopastoral systems. In spite of the convincing research results showing the excellent potential of leucaena to increase forage quality and animal production in suitable areas, there has been poor adoption of this forage tree legume on a broad scale. Esta revisión describe la historia de investigación conducida por el Instituto Nacional de Tecnología Agropecuaria (INTA) en la utilización de Leucaena leucocephala (leucaena) en sistemas ganaderos en las últimas 5 décadas, y analiza las principales limitantes que resultaron en su escasa adopción en Argentina. Leucaena fue introducida en la región subtropical del norte de Argentina a finales de la década de 1960 y comienzos de los 70s. Desde entonces, INTA ha conducido investigaciones para evaluar la productividad forrajera y ganadera, accesiones de leucaena, cepas de rizobio, contribución de carbono y nitrógeno al suelo, y efectos de la densidad de leucaena sobre competencia y otras interacciones ecosistémicas en sistemas silvopastoriles. A pesar de los alentadores resultados de dichas investigaciones, que mostraron el excelente potencial de leucaena para incrementar la producción forrajera y ganadera en áreas aptas para su crecimiento, se observa escasa adopción de esta leguminosa forrajera arbórea en gran escala. Instituto de Investigación Animal del Chaco Semiárido Fil: Radrizzani Bonadeo, Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Animal del Chaco Semiárido; Argentina. Fil: Pachas, Anibal Nahuel. The University of Queensland. School of Agriculture and Food Sciences; Australia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; Argentina. Fil: Gandara, Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Corrientes; Argentina Fil: Goldfarb, Maria Cristina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Corrientes; Argentina Fil: Perticari, Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; Argentina Fil: Lacorte, Santiago María. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cerro Azul; Argentina. Fil: Pueyo, Joaquin Dante. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria El Colorado; Argentina

Published
2019

12. Water use, root activity and deep drainage within a perennial legume-grass pasture: a case study in southern inland Queensland, Australia = Uso de agua, actividad radicular y drenaje profundo en una pastura leguminosa-gramínea perenne: Un estudio de caso en el sur de Queensland, Australia

Author

Pachas, Anibal Nahuel, Shelton, H. Max, Lambrides, Christopher J., Dalzell, Scott A., Macfarlane, David C., and Murtagh, G. John

Subjects
Plantas Perennes, Leucaena Leucocephala, Leguminosas, Legumes, Perennials, Chloris Gayana, Uso del Agua, Agroforesteria, Drainage, Drenaje, Grasses, Agroforestry, Water Use, Queensland, Australia, Gramineas
Abstract

Water use and depth of water extraction of leucaena (Leucaena leucocephala) and Rhodes grass (Chloris gayana) pasture, irrigated with desalinated coal seam water (a by-product of the coal seam gas industry), were monitored to provide background information on root activity, spatial and temporal water use and deep drainage over a 757-day period from August 2011 to August 2013. Methodology comprised measurement of soil water from surface to 4 m depth using 8 EnviroSCAN probes connected to dataloggers positioned within leucaena twin rows and within the Rhodes grass inter-row. Just over 581,000 individual moisture measurements were collated and are reported here. Water extraction (and by inference root activity) of leucaena and Rhodes grass showed marked seasonal fluctuation with deepest and highest water extraction occurring during the first growing season; water extraction was greatly diminished during the following drier and cooler seasons due to the negative influences of lower soil moisture contents, lower temperatures and increased defoliation on pasture growth. The highest values of deep drainage below 4 m depth occurred when high rainfall events corresponded with high soil water storage in the entire profile (0–4 m depth). Given that water usage by both leucaena and Rhodes grass was greatest in the upper layers of soil (

Published
2016

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