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Greenhouse gas mitigation potential of the world’s grazing lands: Modeling soil carbon and nitrogen fluxes of mitigation practices

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Greenhouse gas mitigation potential of the world’s grazing lands: Modeling soil carbon and nitrogen fluxes of mitigation practices Henderson, B.B.; Gerber, P.J.; Hilinski, T.E.; Falcucci, A.; Ojima, D.S.; Salvatore, M.; Conant, R.T. This study provides estimates of the net GHG mitigation potential of a selected range of management practices in the world’s native and cultivated grazing lands. The Century and Daycent models are used to calculate the changes in soil carbon stocks, soil N2O emissions, and forage removals by ruminants associated with these practices. GLEAM is used in combination with these models to establish grazing area boundaries and to parameterize links between forage consumption, animal production and animal GHG emissions. This study provides an alternative to the usual approach of extrapolating from a small number of field studies and by modeling the linkage between soil, forage and animals it sheds new light on the net mitigation potential of C sequestration practices in the world’s grazing lands. Three different mitigation practices are assessed in this study, namely, improved grazing management, legume sowing and N fertilization. We estimate that optimization of grazing pressure could sequester 148 Tg CO2 yr−1. The soil C sequestration potential of 203 Tg CO2 yr−1 for legume sowing was higher than for improved grazing management, despite being applied over a much smaller total area. However, N2O emissions from legumes were estimated to offset 28% of its global C sequestration benefits, in CO2 equivalent terms. Conversely, N2O emissions from N fertilization exceeded soil C sequestration, in all regions. Our estimated potential for increasing C stocks though in grazing lands is lower than earlier worldwide estimates (Smith et al., 2007 and Lal, 2004), mainly due to the much smaller grazing land area over which we estimate mitigation practices to be effective. A big concern is the high risk of the practices, particularly legumes, increasing soil-based GHGs if applied outside of this relatively small effective area. More work is needed to develop indicators, based on biophysical and management characteristics of grazing lands, to identify amenable areas before these practices can be considered ready for large scale implementation. The additional ruminant GHG emissions associated with higher forage output are likely to substantially reduce the mitigation potential of these practices, but could contribute to more GHG-efficient livestock production.

Exposure of vaccinated and naive cattle to natural challenge from buffalo-derived Theileria parva

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Exposure of vaccinated and naive cattle to natural challenge from buffalo-derived Theileria parva Sitt, T.; Poole, E.J.; Ndambuk, G.; Mwaura, S.; Njoroge, T.; Omondi, G.P.; Mutinda, M.; Mathenge, J.; Prettejohn, G.; Morrison, W.I.; Toye, P. Integrative management of wildlife and livestock requires a clear understanding of the diseases transmitted between the two populations. The tick-borne protozoan parasite Theileria parva causes two distinct diseases in cattle, East Coast fever and Corridor disease, following infection with parasites derived from cattle or buffalo, respectively. In this study, cattle were immunized with a live sporozoite vaccine containing three T. parva isolates (the Muguga cocktail), which has been used extensively and successfully in the field to protect against cattle-derived T. parva infection. The cattle were exposed in a natural field challenge site containing buffalo but no other cattle. The vaccine had no effect on the survival outcome in vaccinated animals compared to unvaccinated controls: nine out of the 12 cattle in each group succumbed to T. parva infection. The vaccine also had no effect on the clinical course of the disease. A combination of clinical and post mortem observations and laboratory analyses confirmed that the animals died of Corridor disease. The results clearly indicate that the Muguga cocktail vaccine does not provide protection against buffalo-derived T. parva at this site and highlight the need to evaluate the impact of the composition of challenge T. parva populations on vaccine success in areas where buffalo and cattle are present.

An improved simulation model to predict pre-harvest aflatoxin risk in maize

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An improved simulation model to predict pre-harvest aflatoxin risk in maize Chauhan, Y.; Tatnell, J.; Krosch, S.; Karanja, J.; Gnonlonfin, B.; Wanjuki, I.; Wainaina, J.; Harvey, J. Aflatoxin is a potent carcinogen produced by Aspergillus flavus, which frequently contaminates maize (Zea mays L.) in the field between 40° north and 40° south latitudes. A mechanistic model to predict risk of pre-harvest contamination could assist in management of this very harmful mycotoxin. In this study we describe an aflatoxin risk prediction model which is integrated with the Agricultural Production Systems Simulator (APSIM) modelling framework. The model computes a temperature function for A. flavus growth and aflatoxin production using a set of three cardinal temperatures determined in the laboratory using culture medium and intact grains. These cardinal temperatures were 11.5 °C as base, 32.5 °C as optimum and 42.5 °C as maximum. The model used a low (≤0.2) crop water supply to demand ratio—an index of drought during the grain filling stage to simulate maize crop's susceptibility to A. flavus growth and aflatoxin production. When this low threshold of the index was reached the model converted the temperature function into an aflatoxin risk index (ARI) to represent the risk of aflatoxin contamination. The model was applied to simulate ARI for two commercial maize hybrids, H513 and H614D, grown in five multi-location field trials in Kenya using site specific agronomy, weather and soil parameters. The observed mean aflatoxin contamination in these trials varied from <1 to 7143 ppb. ARI simulated by the model explained 99% of the variation (p ≤ 0.001) in a linear relationship with the mean observed aflatoxin contamination. The strong relationship between ARI and aflatoxin contamination suggests that the model could be applied to map risk prone areas and to monitor in-season risk for genotypes and soils parameterized for APSIM.

Abstracts for 2015 Integrated Nutrition Conference

CRP 4 program news -

 

 

DEADLINE:  Please submit your abstract by July 3rd (11:59 PM EST).

 

Conference Details

Conference theme: 1,000 Days of Life: New Approaches for Integrated Strategies to Improve Children’s Lives

Join Catholic Relief Services (CRS) and members of the NGO, research, and donor community for a two day conference focusing on integrated solutions relevant to East Africa. Global leaders in the areas of nutrition, water and sanitation, agriculture, health and early childhood development will come together to:

  • Bring knowledge, evidence and experience on implementing integrated nutrition-sensitive programming;
  • Identify best practices in integrated nutrition-sensitive programs;
  • Identify gaps that will lead to the development of a learning agenda for East Africa; and
  • Facilitate networks among stakeholders.

Abstract Details

Add your voice. We're seeking abstracts for oral and poster presentations focusing on:

  • Effectiveness, pathways of impact and cost of integrated nutrition-sensitive programs on nutrition outcomes;
  • Strategies for implementing integrated nutrition-sensitive programs for improving nutritional outcomes.

Deadline for submitting abstracts is July 3, 11:59 PM EST.

The abstract review committee consists of experts from A4NH, Strengthening Partnerships, Results, and Innovations in Nutrition Globally (SPRING) project, and Catholic Relief Services. Rajul Pandya-Lorch, head of IFPRI’s 2020 Vision for Food, Agriculture, and the Environment Initiative and IFPRI Chief of Staff will moderate the conference.

Please join us. Visit the conference website to submit your abstract.

If you have any questions, please contact Emily Bostick, CRS’ East Africa Regional Technical Advisor for Health or Valerie Rhoe Davis, Senior Technical Advisor for Agriculture, Gender and Nutrition at EARO_Integrated_Nutrition_Conference@crs.org. We look forward to seeing you at the conference!

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