RESTORATION OF BIOTA IN ARABLE CHERNOZEMS BY GREEN MANURING AND PERENNIAL GRASSES

The status of biota of old-arable chernozems in conditions of the green manure and perennial grasses applications has been evaluated statistically. Two experimental sites located in the central and southern zone of the Republic of Moldova have been tested by biological indicators during 2010-2012. The application of vetch as a green manure and grassesand-legumes created conditions for the improvement of the biota’s vital activity in the soil which degraded as a result of a long-term arable use. The effect of green manure was manifested in the increase of the share of Lumbricidae family in the total number of invertebrates by 12.1-20.8% and the microbial biomass productivity of 1.4 to 1.5 times. The use of the mixture of ryegrass + lucerne during 3-5 years led to the growth of the number of invertebrates and Lumbricidae family by 2.5 and 3.0, their biomass - by 1.6-2.0 times in comparison with the control plot. Invertebrates’ diversity has improved. The microbial biomass content and dehydrogenase activity in the 0-25 cm layer were increased in average by 1.4 times. The microbial biomass accumulated in the soil in amounts of 494.6-830.1 kg ha -1 or an average of 132.5 kg ha -1 annually. The population growth of worms reached of 74.4 ex m -2 (744.000 ex ha -1 ), or 14.9 ex m -2 (149.000 ex ha -1 ) annually. An interconnection of biological parameters of the soil quality is under discussion.