ROOT ASSESSMENT IN DIVERSIFIED AGRICULTURAL SYSTEMS: A METHODOLOGICAL CONTRIBUTION

Soil organic matter (SOM) is a key component in the agricultural soils, being strongly influenced by carbon (C) inputs derived from roots systems. However, the quantification of root-derived C remains limited, largely due to methodological challenges associated with root sampling and the efficient separation of roots from soil. This study aimed to describe and apply a standardized methodology for root sampling and washing across different crop diversification systems. The field experiment was established four years ago in Sorriso-MT, Brazil, on a clay-textured Oxisol, evaluating three treatments during the off-season followoing soybean, arranged in a randomized complete block design with four replications: 1)maize; 2)maize+brachiaria; and 3)maize +brachiaria+crotalaria. Soil round monoliths were collected using a 7,5 cm diameter iron cylinder to a depth of 50 cm, divided into five 10 cm layers, at three equidistant positions. Roots were separated from the soil using a well-established washing protocol, adapted to the study conditions, involving soil disaggregation in water, fine-mesh sieving (0,5 mm), suspension and manual separation with trays and tweezers, followed by root preservation in alcohol. The method proved to be applicable to different systems with diversified root architectures and suitable for field or laboratory conditions, showing good repeatability and enabling the recovery of fine root fractions. Methodological standardization contributes to reducing sampling variability and reinforces the potential role of roots in contributing to soil C accumulation in tropical agricultural systems.