STABILITY AND SORPTIVITY OF SOIL AGGREGATES IN GRASSED AND CULTIVATED SLOPING VINEYARDS

摘要

The physical characteristics of soil aggregates influence soil tilth, surface sealing, water infiltration and root growth. Soil management and compaction significantly affect these characteristics. The aim of this work was to determine the effects oftractor traffic across the slope on bulk density, water stability, tensile strength and sorptivity of aggregates from grass covered and cultivated sloping (18%) vineyard soils. The grass covered (G) treatment included periodical mowing and cutting back of herbage and cultivation (C) treatment consisting of autumn ploughing (18 cm) and spring and summer rotary hoeing in the vineyard inter-row zones (2.7 m). A crawler tractor (2.82 Mg) was used in the inter-row zones, moving across the slope for all tillage and chemical operations. Soil aggregates were taken from the inter-rut and the upper and lower rut areas (0-10 and 20-30 cm) in the inter-row zones and then air-dried. Bulk density and tensile strength were lowest in the inter-rut areas and highest inthe lower crawler rut. Aggregate water stability was greater under the lower rut and sorptivity in the inter-rut area in comparison to the remaining inter-row areas. In comparable inter-row areas, water stability and sorptivity of soil aggregates were greater and lower under G than C, respectively. The differences in bulk density and tensile strength between G and C were not consistent and varied depending on the inter-row zone and depth.