Nutrients Metabolism of Agricultural Production in Argentina: NPK Input and Output Flows from 1961 to 2015

Abstract

Argentina has historically collected large amounts of nutrients in harvested products for worldwide consumption, relying on the high productivity of its soils. We estimated NPK nutrient flows and partial balance based on historical data for biomass production and fertilizer use, from 1961 to 2015, to better understand intensity and temporal variability of nutrient dynamics in Argentina. Estimated NPK output accumulated 113.6Mt. (78.4Mt. N, 10.8Mt. P, 24.4Mt. K), or an annual average of 67kg N, 9kg P and 21kg K per harvested hectare. Cumulate NPK supplied in fertilizers explained 15% N, 44% P and 4% K total extraction. Nutrient balance shows 53% (60Mt) of total NPK outputs came from sources other than fertilizer, fixation or deposition, implying soil depletion. Nutrient deficits cumulate −30Mt. N, −6Mt. P and −24Mt. K, equal to −26kg N, −5kg P and −20kg K per harvested hectare each year. Soybean was the most extractive crop, with 54% of accumulated NPK removed. The estimation approach is robust because it focuses on NPK major sinks and sources from long and reliable data sets, as an indirect way to assess soil nutrient use and stock tendency.