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First Harvest (first + harvest)
Selected AbstractsBeyond Reaping the First Harvest: Management Objectives for Timber Production in the Brazilian AmazonCONSERVATION BIOLOGY, Issue 4 2007DANIEL J. ZARIN manejo de bosques; producción sostenida; sustentabilidad; tala de impacto reducido Abstract:,Millions of hectares of future timber concessions are slated to be implemented within large public forests under the forest law passed in 2006 by the Brazilian Congress. Additional millions of hectares of large, privately owned forests and smaller areas of community forests are certified as well managed by the Forest Stewardship Council, based on certification standards that will be reviewed in 2007. Forest size and ownership are two key factors that influence management objectives and the capacity of forest managers to achieve them. Current best ecological practices for timber production from Brazil's native Amazon forests are limited to reduced-impact logging (RIL) systems that minimize the environmental impacts of harvest operations and that obey legal restrictions regarding minimum diameters, rare species, retention of seed trees, maximum logging intensity, preservation of riparian buffers, fire protection, and wildlife conservation. Compared with conventional, predatory harvesting that constitutes >90% of the region's timber production, RIL dramatically reduces logging damage and helps maintain forest cover and the presence of rare tree species, but current RIL guidelines do not assure that the volume of timber removed can be sustained in future harvests. We believe it is counterproductive to expect smallholders to subscribe to additional harvest limitations beyond RIL, that larger private forested landholdings managed for timber production should be sustainable with respect to the total volume of timber harvested per unit area per cutting cycle, and that large public forests should sustain volume production of individual harvested species. These additional requirements would improve the ecological sustainability of forest management and help create a stable forest-based sector of the region's economy, but would involve costs associated with lengthened cutting cycles, reduced harvest intensities, and/or postharvest silviculture to promote adequate growth and regeneration. Resumen:,Bajo la nueva ley forestal aprobada en 2006 por el Congreso Brasileño, millones de hectáreas de bosques públicos están destinadas a constituir futuras concesiones madereras. Millones de hectáreas adicionales de extensos bosques privados y áreas reducidas de bosques comunitarios están certificadas por el Forest Stewardship Council por su buen manejo, con base en estándares de certificación que serán revisados en 2007. La extensión y tenencia del bosque son dos factores clave que influyen en los objetivos de manejo y en la capacidad de los manejadores para alcanzarlos. Las mejores prácticas ecológicas actuales para la producción de madera en los bosques de la Amazonía Brasileña están limitadas a sistemas de tala de impacto reducido (TIR) que minimizan los impactos ambientales de las operaciones de cosecha y que obedecen restricciones legales en relación con los diámetros mínimos, las especies raras, la retención de árboles semilla, la máxima intensidad de tala, la preservación de amortiguamientos ribereños, la protección del fuego y la conservación de vida silvestre. En comparación con la cosecha convencional, depredadora, mediante la cual se obtiene >90% de la producción de madera en la región, la TIR dramáticamente reduce el daño y ayuda a mantener la cobertura del bosque y la presencia de especies de árboles raras, pero los actuales lineamientos de TIR no aseguran que el volumen de madera removida pueda ser sostenido en futuras cosechas. Consideramos que es contraproducente esperar que los pequeños propietarios suscriban límites a la cosecha más allá de la TIR; que los bosques privados manejados para la producción de madera debieran ser sustentables respecto al volumen total de madera cosechada por unidad de área por ciclo de corte; y que los bosques públicos deberían sustentar el volumen de producción de especies individuales. Estos requerimientos adicionales mejorarían la sustentabilidad ecológica del manejo de bosques y ayudaría a crear un sector forestal estable en la economía regional, pero implicarían costos asociados con la prolongación de los ciclos de corte, la reducción de las intensidades de cosecha y/o la silvicultura postcosecha para promover el crecimiento adecuado y la regeneración. [source] Forage and biomass feedstock production from hybrid forage sorghum and sorghum,sudangrass hybridsGRASSLAND SCIENCE, Issue 4 2008Brad Venuto Abstract As the bioenergy industry expands, producers choosing to shift current forage crop production to dedicated biomass crops can benefit from growing lower risk multipurpose crops that maximize management options. Hybrid forage sorghums (HFS) and sorghum,sudangrass hybrids (SSG) are capable of impressive biomass yields and tolerance to environmental stress. Multiple vegetative harvests (ratoon harvests) of sorghum are possible and there are photoperiod-sensitive sorghums that remain vegetative. However, the response of newer HFS and SSG cultivars to harvest management practices designed for forage or cellulosic feedstock production has not been fully investigated in all environments. The objectives of this study were to: (i) determine biomass production and quality characteristics of a genetically diverse range of HFS, SSG and sudangrass cultivars and evaluate their interaction with harvest system; and (ii) provide data to aid selection of sorghum cultivars for both forage and biofuel uses. Mean yield across all entries and years for a single late season harvest was 27.1 Mg ha,1 of dry matter per year. Mean total yield for a first harvest plus a ratoon crop was 25.5 Mg ha,1 of dry matter per year. However, entries varied for yield and interacted with harvest system. Mean caloric value was 16.5 Gj Mg,1 and modest differences were observed among cultivars evaluated. The best performing entry (cv. Tentaka) yielded 40.3 Mg ha,1 of dry matter for a single late season harvest, demonstrating the biomass potential of existing sorghum cultivars, specifically those possessing photoperiod- and/or thermosensitive genotypes. [source] Effect of an arbuscular mycorrhizal fungus, Glomus mosseae, and a rock-phosphate-solubilizing fungus, Penicillium thomii, on Mentha piperita growth in a soilless mediumJOURNAL OF BASIC MICROBIOLOGY, Issue 3 2005Marta Cabello Dr. Rock phosphate effect on English mint (Mentha piperitaL.) grown on steamed perlite:vermiculite (1:1, v:v) substrate, with and without rock phosphate, was evaluated in greenhouse experiments. Five treatments were carried out by inoculation with an arbuscular mycorrhizal fungus Glomus mosseae and a phosphorus solubilizing microorganism Penicillium thomii. Plant aerial biomass, phosphorus concentration in plant tissue, and P available in the substrate, were evaluated upon two harvests. After the first harvest, plant aerial biomass did not show significant differences between treatments using rock phosphate as fertilizer, although P content in plants inoculated with P. thomii was higher. The second harvest revealed a higher biomass and plant tissue P content in treatments inoculated with G. mosseae. P. thomii increased P available in the substrate, whereas in the absence of G. mosseae, it did not enhance plant tissue P content. Mycorrhizal colonization was not affected by P. thomii. Microbial inoculation effect on English mint growth was also evaluated. The microbial effect was positive in all treatments when compared with the control without rock phosphate. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effect of Salt Stress on Carbon Metabolism and Bacteroid Respiration in Root Nodules of Common Bean (Phaseolus vulgaris L.)PLANT BIOLOGY, Issue 4 2000A. Ferri Abstract: In the present work, we examined the effect of salinity on growth, N fixation and carbon metabolism in the nodule cytosol and bacteroids of Phaseolus vulgaris, and measured the O2 consumption by bacteroids incubated with or without the addition of exogenous respiratory substrates. The aim was to ascertain whether the compounds that accumulate under salt stress can increase bacteroid respiration and whether this capacity changes in response to salinity in root nodules of Phaseolus vulgaris. The plants were grown in a controlled environment chamber, and 50, 100 mM or no NaCl (control) was added to the nutrient solution. Two harvests were made, at the vegetative growth period and at the beginning of the reproductive period. The enzyme activities in the nodule cytosol were reduced by the salt treatments, while in the bacteroid cytosol the enzyme activities increased at high salt concentrations at the first harvest and for ADH in all treatments. The data presented here confirm that succinate and malate are the preferred substrates for bacteroid respiration in common bean, but these bacteroids may also utilize glucose, either in control or under saline conditions. The addition of proline or lactate to the incubation medium significantly raised oxygen consumption in the bacteroids isolated from plants treated with salt. [source] Effect of partial harvesting strategies on Artemia biomass production in Vietnamese salt worksAQUACULTURE RESEARCH, Issue 9 2010Nguyen Thi Ngoc Anh Abstract The effect of partial harvest strategies on the production of Artemia biomass was evaluated for 12 weeks under Vietnamese salt farm conditions. The initial stocking density was 100 nauplii L,1. After 3 weeks of inoculation, Artemia adults were partially harvested at intervals of 1, 3, 6 and 9 days starting with an initial quantity of 30 kg ha,1 day,1 at first harvest, and then the quantity of harvestable biomass was adjusted according to the standing stock present in the culture pond, combined with the time needed to harvest these quantities and with the weight of biomass harvested in each pond. The results showed that in most cases, the total densities were not significantly different among harvesting frequencies (P>0.05). However, a relatively higher Artemia adult density and its standing stock were better maintained in the 3-day than in the 1-day interval, and were significantly higher compared with the other two harvesting frequencies. The total biomass yields were the highest (1587 kg ha,1) in the 3-day harvesting interval, followed by 1-, 6- and 9-day harvesting interludes, corresponding to 1323, 1091 and 975 kg ha,1 respectively. However, no statistical difference was observed between the 1- and the 3-day interval as well as between the 6- and the 9-day harvest schemes (P>0.05). The results of this study suggest that partial harvest of Artemia biomass performed every 3 days appears to be an appropriate strategy to enhance biomass productivity. [source] Feasibility of pacific white shrimp Litopenaeus vannamei culture in southern Brazil: effects of stocking density and a single or a double CROP management strategy in earthen pondsAQUACULTURE RESEARCH, Issue 2 2010Dariano Krummenauer Abstract Marine shrimp culture at southern Brazil is restricted to the warmer season (November to April). Therefore, farmers must consider culture strategies and competition with shrimp landings from artisanal fishery. The fishing season starts every 1 February; in order to obtain higher prices, farmers may consider shrimp culture in two crops, with a first harvest before the start of the fishing season, and a second harvest after the end of the landings. The present study evaluated the performance and feasibility of Litopenaeus vannamei reared at 10, 25 and 40 shrimp m,2 either in two short consecutive culture cycles or one longer cycle (LC). The experimental design consisted of two sets of nine pens installed in a 3.8 ha earthen pond. In one set of pens, shrimp were harvested after 75 days and pens were restocked for another 75-day-long rearing period. In the second set of pens, shrimp were cultured for 150 days. Shrimp survival and final weight ranged from 79% to 91% and 6.67 to 14.53 g respectively. Feasibility analysis pointed towards culture at higher densities (25 and 40 shrimp m,2) in a LC as productivity (2274,4227 kg ha,1) and shrimp final weight (13.05,13.21 g) resulted in higher profitability (US$7761,12 379). [source] Simulation of optimal harvesting strategies for small-scale mixed-sex tilapia (Oreochromis shiranus Boulenger 1896) ponds using a bio-economic modelAQUACULTURE RESEARCH, Issue 4 2007Francis Saiti Abstract A cohort-based bio-economic biomass growth and economic model, validated with data from experiments conducted in Malawi, was used to identify an optimal harvesting strategy for mixed-sex tilapia ponds. Three harvesting scenarios (baseline, economic optimum time +10 days and economic optimum time) were used. In each harvesting scenario four options were explored: (i) no further harvest, harvest every (ii) 60 days, (iii) 90 days and (iv) 120 days after initial harvest. The lowest simulated yield (487 kg ha,1 year,1) was obtained when no partial harvesting was carried out and fish were harvested after 365 days. Maximum yield (4416 kg ha,1 year,1) was obtained when partial harvests were carried out every 90 days starting with a first harvest of fish weighing 60 g or more at day 90. Maximum financial returns (US$2561 ha,1 year,1) were obtained when partial harvests were carried out every 120 days starting with the first harvest at day 90 and removing all fish ,60 g. The model simulations indicate that mixed-sex tilapia culture may be profitable for tilapia farmers in Africa where markets accept small (60,150 g)-sized fish. The study further shows that a cohort-based population growth model can be reliably incorporated in tilapia production models to simulate fish yields in mixed-sex tilapia production systems. However, incorporation of intergenerational competition effects could improve the model's utility as a decision support tool for managing mixed-sex tilapia production. [source] | |||||||||||||