TILLAGE EFFECT ON SOIL ORGANIC MATTER, MYCORRHIZAL HYPHAE AND AGGREGATES IN A MEDITERRANEAN AGROECOSYSTEM

arbuscular mycorrhizal fungi (amf) and their product glomalin (grsp) play a decisive role in the soil aggregation, affecting the carbon (c) dynamics in agroecosystems. tillage affects the amf activity and grsp content, influencing the stability and the soil c forms as well. the aim of this study was to compare the effect of no tillage (nt) and conventional tillage (ct) on: i) arbuscular mycorrhizal hyphal length and grsp content; ii) the nature of soil organic matter by means of physical fractionation (free paniculate organic matter [fpom]; occluded paniculate organic matter [opom] and mineral-associated soil organic matter [mineral]), as well as chemical fractionation (fulvic acid, humic acid and humin), and iii) the relationships between amf parameters, soil carbon and water stable aggregates (wsa) in a mollisol of central chile managed for 6 years under nt and ct using a wheat-corn rotation. higher values in the amf hyphal length, grsp and wsa in nt compared with ct were observed. significant relationships were found between grsp and wsa (r = 0.66, p < 0.01) and total mycelium and grsp (r = 0.58, p< 0.05). the total carbon increased 44% under nt compared with ct. the chemical fractionation showed percentage greater than 95% for humim in both treatments. physical fractionation indicates that the higher part of the soc (89.4 - 95.1%) was associated with the mineral fraction.