Biometrical applications in tropical pasture and agro-pastoral research

"Biometrical Applications in Tropical Pasture and Agro-pastoral Research" illustrates, through selected Case Studies, the contribution of Biometry to pasture and agro-pastoral research in Tropical Latin America ( TLA ) in the last two decades. Its contribution is represented in research concepts, methodology, and practical research results that help increase land and animal productivity, human welfare, and efficient conservation and management of natural resources.The selected Case Studies were conducted in various countries of TLA, on the two major ecosystems of the lowland tropics: the Savanna Ecosystem , with 250 million ha, and the Tropical Forest Ecosystem , with 44 million ha. Each Case Study was part of the research agenda and strategy of CIAT (Centro Internacional de Agricultura Tropical, or International Centre for Tropical Agriculture, based in Cali, Colombia), the RIEPT (Red Internacional de Evaluación de Pasturas Tropicales, or International Network for Tropical Pastures Evaluation), the Agro-pastoral Research Network for the Savanna Ecosystem of Tropical America, and pasture and agro-pastoral research programs from Latin American National Agricultural Research and Development Institutions. Each Case Study aimed at solving concrete research problems of pasture and agro-pastoral research in TLA and has been published in relevant scientific media, especially in those addressing needs of Latin American researchers.The different Case Studies (presented in chapters 3 to 9) show a "gradient" in research scale: --from controlled, small-plot, multilocational agronomic research conducted at the Experiment Station to characterise and evaluate a large number of forage grass and legume ecotypes, to medium-size grazing experiments conducted to evaluate a smaller number of pastures (grass-alone or grass-legume associations) both at the Experiment Station and at the farm, ending with agro-pastoral experiments aimed at integrating research findings from the two previous research phases into economically attractive pasture-crop production systems--. Chapter 2 is of a conceptual nature. It summarises the role of Biometry in pasture and agro-pastoral research. The last chapter (chapter 10) deals with organisation and resources of Biometry Units in Latin American Agricultural Research Institutions and offers practical recommendations concerning the desired role of the biometrician as a true partner in research teams.Chapter 3 illustrates the selection process for promising forage grass and legume ecotypes and identifies promising material. Chapter 4 defines "adaptation niches" for an important pasture cultivar identified as promising by the previous case study: the legume Stylosanthes guianensis 184. Chapter 5 presents concepts and methods for the planning, design and analysis of grazing experiments, with emphasis on continuous designs for evaluating beef production. Chapters 6 and 7 present concepts, methods and research solutions concerning the design and analysis of milk and dual-purpose production experiments using Bos taurus and Bos taurus × Bos indicus cows, of different genetic levels, both at the Experiment Station and at the farm. Chapters 8 and 9 discuss concepts, methodology and research results concerning the planning, design and analysis of agro-pastoral experiments for the Savanna Ecosystem of TLA.</p

Drought impact on forest carbon dynamics and fluxes in Amazonia

In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the absence of growth. We propose that weakened maintenance and defence investment may, in turn, cause the increase in post-drought tree mortality observed at our plots.Gordon and Betty Moore FoundationNatural Environment Research Council (NERC)EU FP7 Amazalert (282664) projectEU FP7GEOCARBON (283080) projectNational Council for Scientific and Technological Development (CNPq, Brazil)ARC - fellowship awardERC - Advanced Investigator AwardRoyal Society - Wolfson Research Merit AwardJackson FoundationJohn Fell Fun

Metodologia parcial de analisis proyecto "desarrollo del gusano cachon en la yuca"

Part of the methodology of the analysis applied to the project of the hornworm (Erinnyis ello) on cassava is presented. The project studies the hornworm life cycle and population dynamics and the economic impact on cassava production under 2 conditions (1) in cages with controlled ideal conditions for development and (2) under field conditions on 19 farms with biological control by the egg parasite Trichogramma sp. and predation by Polistes erythocephalus (on 10 farms only). The theoritical structure of the Markov and semi-Markov stochastis processes is given; the models used are based on the latter. (CIAT

Carbon sequestration in tropical grassland ecosystems

The increasing scientific consensus on global warming, together with the precautionary principle and the fear of non-linear climate transitions is leading to increasing action to mitigate global warming. To help mitigate global warming, carbon storage by forests is often mentioned as the only or the best way to reduce the CO2 concentration in the atmosphere. This book presents evidence that tropical grasslands, which cover 50% of the earth’s surface, are as important as forests for the sequestration of carbon. Results are reported of a large five year on-farm research project carried out in Latin America (Colombia, Costa Rica). Soil and vegetation carbon stocks of long-established pasture, fodder bank and silvopastoral systems on commercial farms were compared with those of adjacent forest and degraded land. The objective was to identify production systems that both increase livestock productivity and farm income and, at the same time, contribute to a reduction of carbon accumulation in the atmosphere. The project was carried out in four ecosystems: the Andean hillsides of the semi-evergreen forest in Colombia; the Colombian humid Amazonian tropical forest ecosystem; the sub-humid tropical forest ecosystem on the Pacific Coast of Costa Rica; and the humid tropical forest ecosystem on the Atlantic Coast of Costa Rica

Carbon sequestration in tropical grassland ecosystems

The increasing scientific consensus on global warming, together with the precautionary principle and the fear of non-linear climate transitions is leading to increasing action to mitigate global warming. To help mitigate global warming, carbon storage by forests is often mentioned as the only or the best way to reduce the CO2 concentration in the atmosphere. This book presents evidence that tropical grasslands, which cover 50% of the earth’s surface, are as important as forests for the sequestration of carbon. Results are reported of a large five year on-farm research project carried out in Latin America (Colombia, Costa Rica). Soil and vegetation carbon stocks of long-established pasture, fodder bank and silvopastoral systems on commercial farms were compared with those of adjacent forest and degraded land. The objective was to identify production systems that both increase livestock productivity and farm income and, at the same time, contribute to a reduction of carbon accumulation in the atmosphere. The project was carried out in four ecosystems: the Andean hillsides of the semi-evergreen forest in Colombia; the Colombian humid Amazonian tropical forest ecosystem; the sub-humid tropical forest ecosystem on the Pacific Coast of Costa Rica; and the humid tropical forest ecosystem on the Atlantic Coast of Costa Rica