Submitted to: International Soil Tillage Research Organization Abstracts
Publication Type: Proceedings
Publication Acceptance Date: 6/5/2003
Publication Date: 6/27/2003
Citation: Brown, G.G., Norton, L.D., Alberton, O., Brandao, O., Saridakis, G.P., Torres, E. Scarabl beetle-grub holes and their importance for soil porosity and water infiltration in various tillage and crop management systems at EMBRAPA Soybean, Londrina, Brazil. CD-ROM. Brisbane, Australia: International Soil Tillage Research Organization Abstracts. 2003.
Technical Abstract: Scarab beetle (white) grubs are not only pests, but they can also have important beneficial effects on the soil by burying litter and creating vertical holes that act as preferential pathways for water infiltration in large storms. With the aim of studying the effect of white-grubs on the physical and hydrological properties of an Oxisol at the Embrapa Soybean Research Station, the number, diameter and depth of beetle-grub holes opened at the soil surface were measured in a long-term (13-year old) tillage and cropping systems trial. The measurements were performed in experimental plots submitted to conventional (CT) and no (NT) tillage, or scarification (chisel-plowing) every 3 years. All plots were either in continuous double-cropping (wheat/soybean) or a rotation including lupine/maize-oats/soybean-wheat/soybean. The results revealed that the beetle grub holes were much more abundant in NT (8, 8-9, 6 m-2) than CT (0, 7-1, 3 m-2) plots, where tillage destroys them. The largest and deepest holes were also found in NT (up to 33, 5 mm diameter and 117 cm deep). Consequently the total volume of pores opened in NT was up to almost 10 times greater than in CT. However, the mean diameter and depth of the few holes found in CT tended to be greater than in NT, probably due to the looser soil, and/or the need to go beyond the plow layer. The potential beneficial effect to soil function of these holes in NT systems deserves more attention.