On the concentration of acetic acid in straw and soil

Summary

Freshly harvested wheat straw contained 0.096 g water g⁻¹ dry straw and 180 mM acetic acid. The straw absorbed water more rapidly from wet soil. The concentration of acetic acid fell to about 10 mM within 6 h of incorporation of straw in the soil and then remained relatively constant for a period of 12 days, irrespective of soil moisture content. In soil at its maximum water holding capacity after gravitational drainage, the decline in acetic acid concentration (c) with distance (d) from wheat or barley straw was exponential, with c=c_o e^−nd where c_o is the concentration of acetic acid at the straw surface and n is a constant (0.46 for barley and 0.42 for wheat straw). The presence of acetic acid seems to be a major cause of poor establishment and growth when seeds and seedling roots come into contact with straw.