Nitrogen Mineralization Potential of Soil's Inter-Andean Valley of Huanuco

Abstract

Introduction: fertility diagnosis improves by including the contribution of mineralizable nitrogen (N) from the soil organic fraction. In this work, we estimate the N mineralization potential of representative soils of the Huánuco region. Materials and methods: the management effect on the contents and surface distribution of total organic matter (MOT) and Nan, in relation to the temperature and precipitation of the sites, was studied. Eighteen agricultural soils and 6 pristine soils representative of the region, and samples were taken from two superficial soil strata (0-10 and 10-20 cm). MOT, Nan, and total N were determined. Results: agricultural soils presented higher MOT and Nan than pristine soils, possibly due to the greater contribution of biomass under agriculture. The surface distribution of the Nan followed the trend of the MOT, with a higher concentration in the most superficial stratum. This occurred independent of agricultural or pristine management, although the latter presented greater stratification as a result of non-tillage. The soils studied were grouped into three, according to the mineralization potential of N. Through the Nan:total N relationship, N mineralizations of 0.9 %, 2.5 % and 5 % were estimated for the different groups, related to the environmental conditions of the sites (higher mineralizations in warmer and more humid sites). Conclusions: the evaluated soils presented different potential to mineralize N depending on temperature and precipitation. These results contribute to a better estimation of the N contribution of soils to calculate the N doses.