Desiccation can play a very important role in the changes of soil biological properties. Reinecke et al. (2002) studied the impact of different herbicides on biological activity in several vineyard soils, with and without cover crops. A comparison of microbial activity after treatment with paraquat, simazine, glyphosate and a glyphosate-terbutylazine mixture showed (with the exception of simazine) that herbicide application had a positive influence on it. Any possible negative effects of applied herbicides (Hiller et al. 2009) are mainly due to chemical and textural parameters of treated soil. Roundup desiccation had a retardation effect on mineralization of C org , N org and S org . Total soil organic carbon content and its qualitative characteristics, in particular, are the most important factors affecting sorption-desorption of herbicides in soil (Hiller et al. 2009). Chernozems of Central Europe have been used for cereals production for 7000 years without substantial decreases in fertility (Kunzova and Hejcman 2009). The quoted paper confirms extraordinary stability and certainty in achieved yields of cereals in Chernozems. Therefore their 'settling to rest' (set-aside) occurs less frequently than in less stable soils.The article responds to the question how to maintain or improve the biological properties of luvic chernozem, when was transformed into a land setaside for many years. Different variations of vegetation cover treating, mowing or mulching, followed by all-over black (= Roundup) fallow and re-grassing by a mowed Italian ryegrass monoculture (Lolium multiflorum Lam.), were evaluated. A variant is recommended, in which the biological properties of luvic chernozem were preserved at the best.
ABSTRACTLuvic chernozem (set-aside from 1996) was evaluated. The first period, before Roundup desiccation (2002)(2003), was characterized by black, spontaneous and controlled fallows (mowed with the removal of plant biomass or mulched); the following period (2003)(2004) by black fallow with repeated Roundup applications; and the last period (2004)(2005)(2006) involved re-grassing by a mowed Lolium multiflorum Lam. monoculture. The characterization included microbial biomass, available organic carbon, basal respiration, metabolic quotient, biomass-specific available organic carbon, arylsulfatase activity, soil organic matter carbon and total nitrogen. Mulching of pure cultures of grasses and legumes contributed to a high soil organic matter accumulation. Repeated Roundup desiccation caused a strong (highly significant) decrease of arylsulfatase activity (-28%), however highly significant increase of microbial biomass (+69%) and nitrate-nitrogen (+86%) were determined. The subsequent re-grassing compensated the changes described. The soil biological properties were best preserved on mulched fallow with Lotus corniculatus L. and Festuca pratensis L., also in regard to contamination with weeds.
89Soils set-aside can be mulched, cut, desiccated, sown with pure cultures, sown with mixtures, maintained as spontaneous...
