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Title: A new index to assess nitrogen dynamics in potato (Solanum tuberosum L.) production systems of Bolivia

Author
item SAAVEDRA, ANA KARINA - Foundation Proinpa
item Delgado, Jorge
item BOTELLO, RUBEN - Foundation Proinpa
item MAMANI, PABLO - Foundation Proinpa
item ALWANG, JEFF - Virginia Polytechnic Institution & State University

Submitted to: Agrociencia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2014
Publication Date: 11/5/2014
Citation: Saavedra, A., Delgado, J.A., Botello, R., Mamani, P., Alwang, J. 2014. A new index to assess nitrogen dynamics in potato (Solanum tuberosum L.) production systems of Bolivia. Agrociencia. Agrociencia 48: 667-678.

Interpretive Summary: These results suggest that the Bolivia Nitrogen Index can accurately assess nitrogen dynamics and uptake in vulnerable, high-elevation Andean potato cropping systems. As a result, it can potentially be used as a technology transfer tool to assess nitrogen management practices in such systems. Observed nitrogen uptake across these sites was also correlated with the observed yields across these studies. The mean potato tuber fresh yields in the system were correlated with the nitrogen in the system as estimated by the Nitrogen Index. This study is the first time that the Nitrogen Index tool has been used to evaluate potato systems from low-input agricultural systems in the Andean region of Bolivia. Bolivia is the poorest country in South America, and poverty and agricultural production are related to one another, but this paper shows that if we can increase the nitrogen inputs into these systems, there is potential to significantly increase yields and improve the standard of living of families across Bolivia. The Nitrogen Index is the first multilingual tool that can be used to quickly conduct an analysis across the soils of this region and help users determine how nitrogen needs to be applied to optimize yields. The tool is available as a mobile application for smartphone and tablet systems; the mobile application can be used right in the field and can email the results of a run to any desktop or laptop computer (Delgado et al 2013). As a result of this ease of access, personnel on the ground can use the tool to assess the risk for nitrogen losses from the system and increase yields. There is potential to increase nitrogen applications in these systems without increasing nitrogen losses to the environment, as long as conservation agriculture is also applied to avoid potentially increasing erosion. Future plans include testing a sustainability index that has also been added to the Bolivia Nitrogen Index tool (Monar et al 2013). The use of quick and simple assessment tools such as the Bolivia Nitrogen Index can help users identify these alternatives.

Technical Abstract: Bolivia is the poorest country in South America with over 80% of the rural population under the poverty line. Agricultural productivity is closely correlated with poverty levels across rural Bolivia. Potato (Solanum tuberosum L.) is one of the most important crops for food security in Bolivia and the rest of the Andean region. In many areas of Bolivia, this crop is grown traditionally, and, as a result, national-level yields are low. Traditional management of potato involves use of organic amendments (animal manures) to supply nitrogen. There is a lack of data about improving nitrogen management practices and the use of more advanced technologies to manage potato production areas where traditional practices predominate. We developed a Nitrogen Index for traditional agricultural systems in Bolivia. The Nitrogen Index for Bolivia was developed and tested with metadata collected from two of the few studies available in the scientific literature for high-altitude systems. The Nitrogen Index was able to predict the nitrogen uptake for potato systems at these sites and uptake was correlated with yields (P<0.05). Potato responded significantly to nitrogen inputs and to the total nitrogen available. The Nitrogen Index can be used to assess management practices for traditional potato systems in Bolivia. It can provide information to farmers and technicians, helping them improve nitrogen management to increase yields and food security.