Management of nitrogen nutrient flow under legume practice from La Teresa basin to the Batabanó Gulf

Abstract Nitrogen management in a karst basin is examined through the establishment of legumes Leucaena leucocephala and Phaseolus vulgaris in pasture and crop areas respectively, with the objective of enriching the nutrient flow interrupted by the construction of dams and canals built during the 1990s, which have altered the natural patterns of hydrological variation and transport to the sea. The different soil treatments show low values of overland fluxes to the sea between 0.9623 and 0.9624 kg ha−1 yr−1 for crops, discretely increasing by 0.02% in pasture and by 0.28% for crop + pasture according to the geomorphic potential of the basin. For land use conditions, a positive economic nitrogen balance was estimated in the range of 55–1560 for crops and 22–2400 USD ha−1 yr−1 for pastures, the latter showing positive balances at the lowest fixation rates, confirming that cover management with legumes maximizes gains and minimizes losses for both agricultural and marine ecosystems, providing a source of indirect fertilization downstream where agricultural areas are located. Article highlights In the flat karst region, geomorphological potential is the main factor in predicting the dynamics of sediment movement. Leguminous land use has a weak effect on alleviating pressures on the island's oligotrophic marine ecosystems. In both crop and pasture, a positive annual economic balance of N was found in the range of 55–2400 USD ha−1 yr−1.