Soil physico-hydrical properties changes induced by weed control methods in coffee plantation

Weed management between coffee inter rows plays a key role in minimizing soil degradation processes. Soil structure and, consequently, its pore size distribution (PSD), water retention (SWRC) and availability can be greatly affected by the weed control methods. In this study, the effect of six different weed control methods on pore size distribution of a Haplustox was analyzed. Two soil depths (0-3 and 10-13 cm) were investigated. Weed control methods in the inter row area were: no weed control; post-emergence herbicide (Glyphosate); mechanical mower; hand-hoe weeding; rotary tiller; pre-emergence herbicide (Oxyfluorfen). An adjacent area of native forest close to the field experiment was used as a reference. The application of different weed control methods produced alterations in the soil structure in relation to the native forest as observed by measurements of SWRC and PSD. The upper soil surface layer (0-3 cm) was more sensitive to changes than the lower surface layer (10-13 cm). In the inter row area (between coffee rows), the weed control methods hand hoe weeding, mechanical mower (both mechanical methods) and pre-emergence herbicide decreased the volume of pores responsible for water drainage, with equivalent pore radius > 25 mu m, in the layer 0-3 cm in relation to the 10-13 cm layer.