Weeds/weed seedbank and soil fungi responses to tillage and cropping systems

Abstract

Listen

Translate article

The influences of tillage, crop rotation, and weed management regimes on the weed seedbank in land previously under CRP were determined from 1994 through 1997. The study followed a split-plot design with four replications, two tillage, two cropping systems, and three weed management regimes. Eleven weed species were recorded in 1994 and 1995, and 13 in 1996 and 1997. The seedbank was dominated by broadleaf species throughout the duration of the study. In the first year out of CRP, the seedbanks for common lambsquarters and pigweeds were 10,365 and 31,925 seeds m'^, respectively. The pigweed seedbank increased over time and climaxed at 51,670 seeds m'^ in 1996. The seedbank for foxtail species was only 417 seeds m'^ m 1994, but increased to 7,820 seeds m'^ in 1997. The dramatic buildup of foxtail species seedbank over the 4 yr period was mainly due to a large population increase in the no herbicide weed management regime. Band and broadcast herbicides had similar effects on the weed seedbank. Tillage and crop rotation did not influence the weed seedbank or Shannon's diversity index, nor did they interact with the ' Received for publication . Accepted for publication . Journal Paper no. of the Iowa Agriculture and Home Economics Experiment Station Ames, Iowa. Project no. , and supported by Hatch Act and State of Iowa. 37 weed management regimes in any of the years. The weed seedbank varied with years and time of soil sampling. Fall sampling tended to have a larger seedbank which declined significantly by the spring sampling. The no herbicide treatment also tended to have a more diverse weed seedbank compared to the weed seedbank from band and broadcast weed management regimes. There was an average of one grass and three broadleaf weed species in the three weed management regimes. The use of band and broadcast herbicides reduced the weed seedbank density but did not affect the ntmiber of broadleaf weed species. Nomenclature: Conmion lambsquaters, Chenopodium album L. CHEAL; pigweed species, Amaranthus spp; foxtail species, Setaria spp.