Summary

2. THE MONITORING SYSTEM OF AGRICULTURAL
LANDS
The State Agricultural Monitoring programme was initiated in 1992. It was based on
static observations of antropogenic load impact on agricultural lands in particular
obesrvation areas. With decree of Latvia State Land Service on February 14, 1994,
was affirmed „Regulation on monitoring of agricultural lands of the Republic of
Latvia” (Vucāns et al., 1996; 2000). In seven soil subspecies of three observation
areas, in the period from 1992 to 1998 was studied soil macrofauna, among them also
earthworms.
2.1. Descriptiom of the monitoring sampling plots
Earthworms were sampled in the following sampling plots of complex research areas-
Baldone parish, Riga region (Baldone 1- with higher relief location, Baldone 2- with
lower relief location) in sandy soil; Baldone K in drained marsh peat soil; Dobele
parish, Dobele region (Dobele 1- higher location, Dobele 2- lower) loamy soil;
Priekuli parish, Cesis region (Priekuli 1- higher location, Priekuli 2- lower) sandy
loam soil. Sampling plots were located in fields, which were used according to the
agricultural managemenet plans. Both sampling plots of Baldone were used as
perennial pasturelands. Dobele and Priekuli sampling plots during the observation
period were intensively cultivated- two times per season tilled, monocultures were
cultivated, pesticides and mineral fertilizers were applied. In each observation area, in
order to comprise the soil combinations located on different relief elements, two static
sampling plots of 10 x 10 m were established, one of a higher relief location, the
other- of a lower (in Baldone sampling plot of higher location the earthworm
population had not been formed, therefore it was excluded from data analysis). One
border of the sampling plot conformed to border of catena. In each plot randomly soil
samples were sampled with help of metal soil drill with diameter of 9.6 cm (drill
outlet area: 72.35 cm 2 ) up to 25cm depth. 30 samples were sampled once a year- at
the end of September, at the beginning of October- in the earthworm autumn activity
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