ECOPICS_Mx Monolith aggregate stability

Aggregate stability by mechanical breakdown by shaking after pre-wetting. 

Aggregate stability was determined on soil samples taken at 0.15 m depth without mulch. Five grams of aggregates (3.35 - 5 mm; of diameter) were gently immersed in 50 mL of ethanol for 10 minutes; ethanol was then removed gently with a pipette and the soil material was transferred gently to an 250mL Erlenmeyer flask with 50 mL deionized water and made up to 200mL, they were subjected to 20 cycles of 1 turn / second of movements, emulating the yoder apparatus; the soil material was allowed settle for 30 minutes; water was then extracted with a pipette and the soil material was rewet with 70% ethanol immersing the aggregates in a 50 micron sieve. The 50 micron sieve was gently moved five times to separate fragments < 50 µm; the >50 µm fraction was collected, allowed to aerate at room temperature and constant humidity (25 ° C ± 5 ° C; 25% ± 5%) for 24 hours then gently sieved by hand in a 6-size column (2000, 1000, 500, 200, 100 and 50 µm. The mass percentage of each size fraction was calculated, and the aggregate stability was expressed by computation of mean weight diameter (MWD) calculated as follows: 

MWD= ∑d * , where d is the mean diameter between to sieves (mm) and m the mass fraction (%) remaining in the sieve. The tests were performed on each soil sample per target species -Pinus hartwegii Lupinus montanus Oxylobus arbutifolius- (subdivided in three methodological replicates).