Nitrate Reduction Approaches

Resource /Energy Economics and Policy, Q25,

Estimation of the Optimal Nitrogen Dose in a \u3ci\u3eBrachiaria humidicola\u3c/i\u3e-Corn Rotation System in the Colombian Eastern Plains

Improving nitrogen (N) use efficiency by optimizing the N fertilizer application dose is one way to reduce greenhouse gas (GHG) emissions in agriculture and livestock production, especially in higher demanding crops such as corn. Taking a Brachiaria humidicola (Bh)-corn rotation system in the Colombian Eastern Plains, we seek to determine both the optimal economic dose (OED) and the optimal technical dose (OTD) of N, which allow to maximize income at producer level and minimize environmental impacts. This particular rotation system was chosen as research subject given the presence of the residual effect of Biological Nitrogen Inhibition (BNI) in permanent lots of Bh, which has positive impacts on corn production such as increased yields and better N efficiency. The data for this study was obtained from trials conducted between 2013 and 2017, where corn production in a Bh-corn rotation system (with residual BNI effect) was compared with conventional corn production (without residual BNI effect). For determining the OED and OTD of N, three response models were applied: a pseudo-quadratic model (PQM), a quadratic model (QM) and a discontinuous-rectilinear model (DRM). The results show that the PQM and DRM models turn out to be the most suitable for estimating the OTD producing a better fit for the data, thus the required N doses are not overestimated. Bh-corn treatments require lower OTD and OED compared to the control scenario, which results from the residual BNI effect. The OED is lower than the OTD in the QM and PQM models for the three treatments. Thus, for maximizing profits a lower N dose is required. Both N input and corn sales price variables determine the optimum dose for maximizing the producer\u27s profits. In general, estimating the correct doses of N in a Bh-corn rotation system contributes to improving both efficiency in production and profitability, helping to avoid excessive application of N fertilizers and its associated negative effects on the environment

What and Who Has Determined Adoption? A Study on Improved Forage Technologies in Colombia from an Agricultural Innovation System (AIS) Perspective

The complex process behind the adoption of improved forages in Colombia remains largely unexplored. Despite governmental and scientific efforts to promote and disseminate the implementation of improved forages for the sake of sustainable livestock production, local livestock producers continue to extensively use native species and adoption rates of more efficient forages remain low. This study explores the dynamics behind the development and diffusion of improved forage technologies in Colombia, from the 1960\u27s to the present through an Agricultural Innovation Systems (AIS) perspective. Here we map the agents involved, classify the roles they exerted over time and reconstruct the historical context in which the creation and dissemination of forage technologies in the country took form. Through the use of qualitative research tools such as in-depth interviews, and extensive archival work, we were able to identify various factors determining the course of improved forage adoption processes. First, a gradual decline on public and private investment destined to agricultural research hindered national scientific agendas and affected the continuity of ongoing projects. Second, the primacy of interpersonal relationships further complicates this panorama as it can either interfere with or promote the use of improved forages, subjecting technology dissemination to a non-institutional realm. Thirdly, released technological packages remain incomplete and impede rising adoption rates, mainly due to both Colombia’s low-latitude (and its restrictions for national seed production) and ineffective processes of training and support aimed at local livestock producers. Aside from the identification of key actors and historical trends, the study concludes by suggesting the implementation of a systematic (AIS) approach that gives account of the complex and ever-changing process of forage adoption, its agents, roles, strengths and limitations so that a comprehensive diagnosis can serve as a guideline for future adoption policies in the subject

From Theory to Practice: What Should We Have in Mind When Building Effective and Sustainable Payments for Ecosystem Services (PES) Schemes for Silvo-Pastoral Systems? Evidence from Colombia

In most Latin American countries, payment for ecosystem services (PES) can be a useful strategy for restoration and conservation of the environment, increasing productivity and promoting sustainable development in rural areas. Despite these plausible benefits, PES implementation can be challenging due to the contextual framework in which it takes place (e.g. institutional weakness in the implementation and monitoring stages, limited connectivity among stakeholders, low adoption levels of agricultural technology). This study aims at evaluating PES schemes for silvo-pastoral systems in Colombia by considering six dimensions based on an extensive literature review: policy and governance; social context; environmental context; risks and challenges; dynamics; and monitoring and evaluation approaches. A literature meta-analysis and semi-structured interviews with decision makers were carried out. The results suggest that: 1) It is necessary to restructure PES schemes given their limited scope in developing countries; 2) A new approach towards successful PES schemes should be adopted, transitioning from temporary conservation-oriented PES to schemes focused on the articulation of value chains and thus, transmitting costs to the final consumers; 3) Although policies regarding PES have been increasing, governance systems and responsibility assignments remain unclear; and 4) PES are more likely to be efficient when accompanied by complementary strategies (e.g. technical assistance, mechanisms for market inclusion) and conservation strategies that last in time. This study revealed the difficulties in monitoring territories as well as the underlying dynamics of implementing PES schemes in farms with nettle aptitude to receive them (despite the willingness of the producers). It also highlights the importance of analyzing the cultural and economic dimensions of the producers to assess the assigned importance of nature conservation. This work enriches the debate and informs the dialogue among PES experiences in order to guide public and private strategies in developing countries

Economic Benefits of Sustainable, Forage-Based Cattle Systems in Colombia and Nicaragua

Forage-based cattle systems play a key role in rural economies of developing countries in terms of food security and poverty alleviation, particularly in tropical Latin America. However, they are often related to being a major cause of negative environmental impacts by contributing to increased greenhouse gas emissions, land degradation, and the reduction of biodiversity. Significant resources have been allocated to research and development in forage material improvement, including selection and breeding. A broad range of improved materials were released by private and public sector actors showing superior characteristics in terms of productivity and environmental impacts compared to native or naturalized materials. Profitability is a fundamental attribute to incentivize or generate adoption of new systems by cattle producers, but this information is often not available to the livestock producer or the extension agents supporting decision-making processes. This research provides an overview on the economic viability of integrating different improved forage varieties in sustainably intensified cattle production systems in Colombia and Nicaragua. Our evaluations show that, despite higher establishment and management costs, integrating improved forage technologies (and management practices) in sustainably intensified cattle systems, either as monoculture, grass-legume associations, silvo-pastoral systems, or in combination with improved management strategies (e.g., intensive, or rotational grazing), not only make sense from the environmental and productive perspectives but also in terms of economic viability. In nearly all evaluated scenarios, the economic indicators improve by integrating improved forage technologies. Strong increases were observed for the following indicators: a) net income, b) unit profit margin, c) Net Present Value, d) Internal Rate of Return, and f) benefit-cost ratio. Strong decreases were observed for the following indicators: a) unit production cost, b) risk of obtaining economic loss, c) payback time, d) minimum area required for a profitable system, and e) sensitivity of the system to external shocks. This information will help cattle producers, extensionists and policymakers to make more holistic and informed land-use decisions that include productive, environmental, economic, and social benefits, and by this contributes to the broader adoption of more sustainable production systems

A convergent interaction engine: vocal communication among marmoset monkeys

To understand the primate origins of the human interaction engine, it is worthwhile to focus not only on great apes but also on callitrichid monkeys (marmosets and tamarins). Like humans, but unlike great apes, callitrichids are cooperative breeders, and thus habitually engage in coordinated joint actions, for instance when an infant is handed over from one group member to another. We first explore the hypothesis that these habitual cooperative interactions, the marmoset interactional ethology, are supported by the same key elements as found in the human interaction engine: mutual gaze (during joint action), turn-taking, volubility, as well as group-wide prosociality and trust. Marmosets show clear evidence of these features. We next examine the prediction that, if such an interaction engine can indeed give rise to more flexible communication, callitrichids may also possess elaborate communicative skills. A review of marmoset vocal communication confirms unusual abilities in these small primates: high volubility and large vocal repertoires, vocal learning and babbling in immatures, and voluntary usage and control. We end by discussing how the adoption of cooperative breeding during human evolution may have catalysed language evolution by adding these convergent consequences to the great ape-like cognitive system of our hominin ancestors. This article is part of the theme issue ‘Revisiting the human ‘interaction engine’: comparative approaches to social action coordination’

Putting the cart before the horse? The origin of information donation

Heintz & Scott-Phillips propose that the partner choice ecology of our ancestors required Gricean cognitive pragmatics for reputation management, which caused a tendency toward showing and expecting prosociality that subsequently scaffolded language evolution. Here, we suggest a cognitively leaner explanation that is more consistent with comparative data and posits that prosociality and eventually language evolved along with cooperative breeding

Defining and predicting heat waves in Bangladesh

This paper proposes a heat-wave definition for Bangladesh that could be used to trigger preparedness measures in a heat early warning system (HEWS) and explores the climate mechanisms associated with heat waves. A HEWS requires a definition of heat waves that is both related to human health outcomes and forecastable. No such definition has been developed for Bangladesh. Using a generalized additive regression model, a heat-wave definition is proposed that requires elevated minimum and maximum daily temperatures over the 95th percentile for 3 consecutive days, confirming the importance of nighttime conditions for health impacts. By this definition, death rates increase by about 20% during heat waves; this result can be used as an argument for public-health interventions to prevent heat-related deaths. Furthermore, predictability of these heat waves exists from weather to seasonal time scales, offering opportunities for a range of preparedness measures. Heat waves are associated with an absence of normal premonsoonal rainfall brought about by anomalously strong low-level westerly winds and weak southerlies, detectable up to approximately 10 days in advance. This circulation pattern occurs over a background of drier-than-normal conditions, with below-average soil moisture and precipitation throughout the heat-wave season from April to June. Low soil moisture increases the odds of heat-wave occurrence for 10–30 days, indicating that subseasonal forecasts of heat-wave risk may be possible by monitoring soil-moisture conditions