Estimates of nitrogen and phosphorus in leachate from agricultural soils with high saturation of exchangeable magnesium

Contextualization: The quantification of chemical parameters in the leachate provides technical information for the state of soil health in the face of nutrient loss, therefore, these results are part of the institutional research management of the UNAD in the project called “Effect of amendments and nitrogen fertilization on sugarcane productivity in soil conditions of Valle del Cauca with high saturation of exchangeable Mg+2.

Knowledge gap: In the problem of agricultural soils with a tendency to salinity and high saturation of exchangeable magnesium (Mg+2), the productivity of crops such as sugar cane is limited, and this is how questions are raised about the lack of knowledge of some interactions. of chemical properties of leachates that could contribute to soil management; In this sense, nitrogen (N) and phosphorus (P) are 2 of the most limiting nutrients in sugarcane cultivation systems and their available forms, therefore, a question associated with this problem is: could they be lost through leaching in the soil with different management of amendments?

Purpose: Laboratory determination of the amounts of nitrates and phosphates in leachates from soils with high saturation of exchangeable magnesium to define the agronomic management of different amendments.

Methodology: In soils from Valle del Cauca, soil samples were used with doses and applications of agricultural amendments (calcium sulfate and cachaça compost. The estimation of forms of nitrogen (nitrates) and phosphorus (phosphates) was carried out by colorimetric determination in a time 5-week monitoring.

Results and conclusions: The nitrates and phosphates in the leachates were obtained in soils without the application of amendments; Treatments with cachaça compost determined the lowest losses of phosphates.
Keywords: nitrates, phosphates, soil salinity, sugar cane
55