Browsing by Author "Stehouwer, R."
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- Nutrient cycling and uptake in conservation agriculture production systems in the Andean regionStehouwer, R.; Webber, K.; Gallagher, R.; Alvarado, S.; Barrera, Victor H.; Delgado, Jorge A.; Alwang, Jeffrey R. (2014)Our project conducted multi-year cropping system experiments in two sub-watersheds in Ecuador: a pasture-potato system in the Illangama (3400 m), and a beans-maize system in the Alumbre (2000 m). All experiments included treatments involving tillage, crop residue management and fertilizer inputs. Here we report on yields, nutrient removal and uptake in these CAPS experiments.
- Soil-Plant System Response to Lime and P Fertilizer Amendments in an Andisol in the Ecuadorean AndesWebber, K.; Alvarado Ochoa, S.; Stehouwer, R.; Farías, D. (2014)Poster presented at SANREM IL Annual Meetings, Washington, DC, May 2014. Andisols are soils derived from volcanic ash that make up a mere 1% of the world’s soils. They are geographically localized to regions marked by volcanic activity, including the Andean Highlands of Ecuador, part of the Ring of Fire. Andisols have high organic matter content, high water holding capacity, and high overall native fertility as a result of their unique parent material. However, high rates of phosphorus sorption are also characteristic of many volcanic soils (Andisols) and can limit agronomic productivity. Acid Andisols, like those evaluated in this experiment, experience phosphorus sorption as a result of ligand bonding with amorphous minerals and organic matter, and fixation of phosphate with aluminum and iron oxides. Phosphate removed from the soil solution is strongly held by soil minerals and is not available to plants.