Fate of Avena sterilis ssp. ludoviciana seeds under different burial depths and wheat residue loads

Abstract

Ludo wild oats (Avena sterilis ssp. ludoviciana) is a problematic winter weed across both conventional and conservation agriculture systems where soil disturbance and crop residue retention differ. To better understand its persistence, we compared the fate of primary and secondary seeds placed at 0, 2, 8, or 15 cm burial depths, and under 0, 2, or 3 t/ha wheat (Triticum aestivum L.) residue loads over a 16-month period. The experiment revealed both burial depth and wheat residue load affected the fate of both types of seed. Seedlings of primary and secondary seeds were able to emerge from 15 cm burial depth (17 %), however maximum emergence occurred from the 2 cm depth (71 %) and under 3 t/ha wheat residue (80 %). After 16 months, it was observed that 17 % of the primary and 24 % of the secondary seeds remained viable, but in a quiescent or dormant state. Burying seeds to a depth of >15 cm will be required to help prevent A. sterilis ssp. ludoviciana seedling emergence and possibly to reduce seed viability in the soil. When strategic tillage is applied, it will reduce the surface residue load and thereby reduce seedling emergence.