Carbon and Nitrogen Dynamics of Potato Residues and Sheep Dung in a Two‐Year Rotation Cultivation in the Bolivian Altiplano

Abstract

Abstract In the high Andes, the traditional rotation is two or three years cropping with potatoes and cereals after 5 to 10 years of fallow. In the Bolivian Altiplano, the balance of available soil nitrogen (N) was monitored during 2 years of cultivation after 3 years of fallow. Two varieties of potato were planted in the first year as the head of the rotation. Potatoes or barley were planted in the second year. Fertilization with sheep dung was only applied for potato cropping. The dynamics of decomposition and N‐release of the amendment and the plant residues were measured using litterbag incubation in the field. Using the N‐release rates provided by the litterbag experiment, we modeled the fate of the mineralizable N originating from the sheep dung and the potato residues decomposition of a 2‐year succession to assess if the N supply from fertilization covered the plant demand. Keywords: DecompositionN releaseorganic fertilizationtropical high mountains Acknowledgments We are very grateful to Bruno Buatois (CEFE, CNRS, France) and Claudio Rosales (Institute of Ecology, La Paz, Bolivia) who were the technical assistants in France and in Bolivia for this study. This work was performed in the framework of the TROPANDES programme entitled ‘Fertility management in the tropical Andean mountains: agroecological bases for a sustainable fallow agriculture’ funded by the EU (INCO‐DC No. ERBIC18CT98‐0263).