Resistance to soil compaction of an Oxisol cultivated with coffee plants under different weed management systems.

摘要

The knowledge of the pressure levels that can be applied to the soil under different weed management system (WMS) is important for coffee plantations management. The objective of this study was to evaluate the influence of different weed management systems on the susceptibility to compaction of a Red-Yellow Latossol (Oxisol) (LVA) using soil support capacity (CSC) models. This study was carried out at the Epamig Research Farm in Patroc.nio, state of Minas Gerais, Brazil, in a coffee (Coffea arabica) plantation using Ruby 1192 coffee variety in a 3.8.0.7 m spacing, planted in February 1999. Four WMS were used and the soil samples were collected in-between the rows under the following management systems: (1) no weed control (SC); (2) hoe-weeded (CM); (3) weed control with post-emergence herbicide Glyphosate (HP.S); (4) weed control with pre-emergence Oxyfluorfen (HPR.). Fifteen undisturbed soil samples from each system were collected (in the layers 0-3, 10-13 and 25-28 cm) in July 2004, with a total of 180 samples. The undisturbed soil samples were equilibrated at different moisture contents and subjected to the uniaxial compression test to obtain the soil CSC models. Results suggested that the support capacity of the LVA decreases in the centre of the inter rows in the following order: HPR. in the 0-3 cm layer > CM in the 10-13 cm layer >SC in the 0-3, 10-13, 25-28 cm layers=HP.S in the 0-3, 10-13, 25-28 cm layers=CM at 0-3 and 25-28 cm layers=HPR. in the 10-13 cm layer > HPR. in the 25-28 cm layer. Weed control with HPR. in the 25-28 cm layer was most susceptible, while HPR. in the 0-3 cm layer was most resistant to soil compaction. The management systems SC and HP.S in the 0-3, 10-13, 25-28 cm layers and the managements CM in the 0-3 and 25-28 cm layers and HPR. in the 10-13 cm layer were equally susceptible to soil compaction.