SOIL SURVEY REVEALS A POSITIVE RELATIONSHIP BETWEEN AGGREGATE STABILITY AND ANAEROBICALLY MINERALIZABLE NITROGEN

GARCIA, GV; CAMPOS, ME; WYNGAARD, N; REUSSI CALVO, NI; SANMARTINO, S; COVACEVICH, F; STUDDERT, GA

ECOLOGICAL INDICATORS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020

1470-160X

Anaerobically mineralized nitrogen (AN) in bulk soil (ANBS) has been described as a soil health indicator. Considering that macroaggregates are more sensitive to management practices than the bulk soil (i.e. whole soil), AN within macroaggregates (2000-8000 m, MA) (ANMA) would be a better soil health indicator than ANBS. The aim of this paper was to evaluate if ANMA is a better indicator of: i) soil (SOC) and particulate (POC) organic carbon in bulk soil (SOCBS and POCBS, respectively) and ii) aggregate stability (AS) than ANBS. Soil samples were taken at 0-5 and 5-20 cm from 46 continuous cropping plots (CC) and a reference plot for each CC (pseudo-pristine, PRIS) in Mollisols with contrasting surface textural classes. The AS, SOCBS, POCBS, ANBS, SOC (SOCMA), and POC (POCMA) within MA and ANMA were determined in 0-5 and 5-20 cm soil samples, and estimated at the 0-20 cm layer. The ANMA was a good indicator of SOCBS (R2 0.75, 0.48, and 0.61 at 0-5, 5-20 and 0-20 cm depths, respectively), POCBS (R2 0.66, 0.31 and 0.49, respectively) and AS (R2 0.80, 0.68 and 0.76, respectively). However, ANMA presented a similar capacity to predict SOCBS, POCBS, and AS as ANBS. This is because ANMA was closely related to ANBS. Since ANMA determination is more laborious than ANBS determination, its use as a soil health indicator would not be convenient. Therefore, the use of ANBS would be recommended over ANMA as a variable to monitor soil health.