A. Kanal, EFFECT OF INCORPORATION DEPTH AND SOIL CLIMATE ON STRAW DECOMPOSITIONRATE IN A LOAMY PODZOLUVISOL, Biology and fertility of soils, 20(3), 1995, pp. 190-196
Several studies on the decomposition of straw using the mesh bag techn
ique were carried out under field conditions in south Estonia. Straw o
f spring and winter cereals (Hordeum vulgare L., Secale cereale L., Tr
iticum aestivum L.) was compared over different periods and at two dep
ths (5 and 20 cm). Calculation of straw decomposition was based on the
ash-free organic matter weight loss. Depending on experimental and cl
imatic conditions the decomposition rate fluctuated from 42% to 75% du
ring the Ist year. The three experimental factors incorporation period
, incorporation depth and straw species all had a significant effect o
n the decomposition of straw. The decaying processes proceeded more ra
pidly in the upper layer and during the initial months; later there we
re no differences in decomposition rate between the two depths. During
the period without vegetation, i.e. from freezing (December) to thawi
ng (April) of the soil, the decomposition rate was 6-7% and during aut
umn it was about 10%. Greater loss of straw occurred early in the grow
ing season and in the upper layer. The release of nitrogen from straw
was slow and N quantity in straw increased due to microbiological immo
bilization during the 1st year.