Divina Gracia P. Rodriguez

Research Scientist

(+47) 904 07 276

Ås R9

Visiting address
Raveien 9, 1430 Ås




I earned my Ph.D. in Agricultural and Applied Economics from the University of Illinois at Urbana-Champaign (USA) in 2014. My research relates to environmental and production economics. I assess the impacts of the adoption of agricultural technologies on farmer's productivity and the environment. I also quantify the benefits people gain from ecosystem services.  

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The site-specific nutrient management (SSNM) strategy provides guidelines for effective nitrogen, phosphorus and potassium management to help farmers make better decisions on fertilizer input and output levels in rice (Oryza sativa) production. The SSNM fertilizer recommendations are based on the yield goal approach, which has been frequently cited in empirical studies. This study evaluates the assumptions underlying the SSNM strategy for rice in the top rice-producing countries around the world, including India, Indonesia, the Philippines, Thailand, and Vietnam. Using a generalized quadratic production function, I explore whether major nutrients are substitutes as inputs and if there are complementarities between inorganic fertilizer and soil organic matter (SOM). The results suggest the relationships among major nutrients vary across sites—some inputs are complements, some are substitutes, and some are independent. The SOM also significantly affects the nitrogen fertilizer uptake. I conclude by suggesting that the SSNM strategy can be made to be more adaptive to farmer’s fields if these relationships are accounted for in the fertilizer recommendation algorithm.

To document


We examine the origins, implications, and consequences of yield-based N fertilizer management. Yield-based algorithms have dominated N fertilizer management of corn (Zea mays) in the United States for almost 50 yr, and similar algorithms have been used all over the world to make fertilizer recommendations for other crops. Beginning in the mid-1990s, empirical research started to show that yield-based rules-of-thumb in general are not a useful guide to fertilizer management. Yet yield-based methods continue to be widely used, and are part of the principal algorithms of nearly all current “decision tool” software being sold to farmers for N management. We present details of the theoretical and empirical origins of yield-based management algorithms, which were introduced by George Stanford (1966, 1973) as a way to make N fertilizer management less reliant on data. We show that Stanford’s derivation of his “1.2 Rule” was based on very little data, questionable data omissions, and negligible and faulty statistical analysis. We argue that, nonetheless, researchers, outreach personnel, and private-sector crop management consultants were obliged to give some kind of N management guidance to farmers. Since data generation is costly, it is understandable that a broad, “ball park” rule-of-thumb was developed, loosely based on agronomic principles. We conclude by suggesting that technology changes now allow for exciting new possibilities in data-intensive fertilizer management research, which may lead to more efficient N management possibilities in the near future.


Mapping and valuating ecosystem services has gained increasing attention over the last years and remains high in the research agenda. In this paper, a mixed methods approach is used to valuate ecosystem services provided by the Divici-Pojejena wetland in Romania. A qualitative part relied on focus group discussions and interviews to identify key stakeholders and the ecosystem services provided by the wetland site. The benefit transfer (BT) method was used for the monetary valuation of the identified ecosystem services that the wetland provides. Bird watching opportunities, water quality, and flood prevention services are among the highest valued services, while the amenity services are the least valued among all wetland services.

To document


We determine the production risk effects and welfare implications of single-trait Bt corn adoption in the Philippines. We use a stochastic production function estimation approach that allows for examining the skewness effects of Bt within a damage abatement specification. Our results indicate that Bt corn has a statistically significant yield increasing, risk-increasing (i.e., variance-increasing) and downside risk-reducing (i.e., skewness-increasing) effects. Based on risk premium, certainty equivalent, and loss probability welfare measures, Bt corn farmers in the Philippines are better-off (in absolute terms) relative to non-Bt farmers given Bt corn's dominant yield increasing effect and downside risk-reducing effect.

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Refined forage legumes as local sources of protein feed for monogastrics and high quality fibre feed for ruminants in organic production

Protein supplementation is a challenge in organic livestock production. Use of imported protein feeds on organically managed farms limits the recycling of nutrients. Fractionation of forage legumes, through novel harvesting and biorefining techniques, into protein- and fibre-rich feeds for monogastrics and ruminants, respectively, can increase farm self-sufficiency with feed. Economic, environmental and social sustainability needs to be taken into account when developing concepts for localised food systems.
Mathematical models will be developed for protein yields of lucerne and red clover. Leaf stripping and juice production will be studied in experiments located in different regions in Europe and Turkey and assessed for feed value in monogastrics and ruminants. Concepts of local food systems based on fractionation of lucerne and red clover will be assessed for sustainability. A participatory approach will be used to involve stakeholder groups in the project, and to ensure an effective dissemination of the results. Farmers will be interviewed to study attitudes towards self-sufficiency and barriers for cooperation that may be required in implementing localised food systems.
The proposed project will establish important knowledge about how to improve self-sufficiency in organic livestock production. Farmers and feed industry will learn how to produce local feed for both monogastrics and ruminants by fractionating forage legumes. An assessment of economic, environmental and social aspects can be used to adapt sustainable local food systems in different regions.
Through this new knowledge, the organic agricultural sector will be able to reduce the amount of imported feeds in Europe by increased utilisation of regional biological resources. This complies also with the social demand from consumers requesting 100% of the feeds to be derived from the farm or region (EC, 2013), and the Bioeconomy Strategy of the European Commission (EC, 2015).

Active Updated: 29.11.2020
End: mar 2021
Start: apr 2018

Division of Environment and Natural Resources

RESILIENCE: Building Climate Resilience of Indian Smallholders through Sustainable Intensification and Agroecological Farming Systems to Strengthen Food and Nutrition Security

The overall goal of the project is to improve agricultural productivity, adaptive capacity and livelihoods of smallholders to climate and economic changes. This will be done by building resilience and strengthening the agri-product market value chains.

Active Updated: 13.11.2020
End: sep 2022
Start: oct 2018