N2(C2H2−C2H4) fixation in two species of Ceanothus seedlings in second year postfire chaparral

Research paper by B. A. Ellis, J. Kummerow

Indexed on: 01 Jul '88Published on: 01 Jul '88Published in: Plant and soil


Nitrogen fixation in excised root nodules of 2-year-old, postfireCeanothus tomentosus andC. leucodermis seedlings was measured over an 8-month period using the acetylene reduction method. High levels of NO3−N and NH4−N present in postfire soils were limited to the upper 10 cm and did not inhibit nodulation in these deeper-rooting seedlings. Decreases in acetylene reduction activity occurred with decreased soil moisture and increased soil temperature. Nitrogen gains from these two Ceanothus shrub seedlings totalled 1.6 kg N ha−1 yr−1.