Responses of soil biota to non-inversion tillage and organic amendments : An analysis on European multiyear field experiments
Hose, Tommy D'; Molendijk, Leendert ; Vooren, Laura Van; Berg, Wim van den; Hoek, Hans ; Runia, Willemien ; Evert, Frits van; Berge, Hein ten; Spiegel, Heide ; Sandèn, Taru ; Grignani, Carlo ; Ruysschaert, Greet - \ 2018
Pedobiologia 66 (2018). - ISSN 0031-4056 - p. 18 - 28.
Earthworms - Microbial biomass - Multiyear field experiments - Nematodes - Non-inversion tillage - Organic amendments
Over the last two decades, there has been growing interest on the effects of agricultural practices on soil biology in Europe. As soil biota are known to fluctuate throughout the season and as agro-environmental conditions may influence the effect of agricultural practices on soil organisms, conclusions cannot be drawn from a single study. Therefore, integrating the results of many studies in order to identify general trends is required. The main objective of this study was to investigate how soil biota are affected by repeated applications of organic amendments (i.e. compost, farmyard manure and slurry) or reduced tillage (i.e. non-inversion tillage and no till) under European conditions, as measured in multiyear field experiments. Moreover, we investigated to what extent the effects on soil biota are controlled by soil texture, sampling depth, climate and duration of agricultural practice. Experimental data on earthworm and nematode abundance, microbial biomass carbon and bacterial and fungal communities from more than 60 European multiyear field experiments, comprising different climatic zones and soil texture classes, were extracted from literature. From our survey, we can conclude that adopting no tillage or non-inversion tillage practices and increasing organic matter inputs by organic fertilization were accompanied by larger earthworm numbers (an increase between 56 and 125% and between 63 and 151% for tillage and organic amendments, respectively) and biomass (an increase between 108 and 416% and between 66 and 196% for tillage and organic amendments, respectively), a higher microbial biomass carbon content (an increase between 10 and 30% and between 25 and 31% for tillage and organic amendments, respectively), a marked increase in bacterivorous nematodes (an increase between 19 and 282% for organic amendment) and bacterial phospholipid-derived fatty acids (PLFA; an increase between 31 and 38% for organic amendment). Results were rarely influenced by soil texture, climate and duration of practice.
Effects of elevated CO2 and drought on the microbial biomass and enzymatic activities in the rhizospheres of two grass species in Chinese loess soil
Xue, Sha ; Yang, Xiaomei ; Liu, Guobin ; Gai, Lingtong ; Zhang, Changsheng ; Ritsema, Coen J. ; Geissen, Violette - \ 2017
Geoderma 286 (2017). - ISSN 0016-7061 - p. 25 - 34.
Drought stress - Elevated atmospheric CO - Enzymatic activities - Interactive effect - Microbial biomass - Rhizospheric soil
Elevated CO2 and drought are key consequences of climate change and affect soil processes and plant growth. This study investigated the effects of elevated CO2 and drought on the microbial biomass and enzymatic activities in the rhizospheres of Bothriochloa ischaemum and Medicago sativa in loess soil. Drought exerted significant species-specific negative effects on root and shoot biomass and microbial properties except for the soil basal respiration in the rhizospheres of B. ischaemum and M. sativa. Increased CO2 exerted weak effects on plant biomass and enzymatic activities but demonstrated significant effects on the amounts of carbon and nitrogen in soil microbial biomass, basal respiration, substrate-induced respiration, and the metabolic quotients in the rhizospheres of M. sativa and B. ischaemum. The rhizosphere soil microbial index was a good aggregative indicator of the general state of the microbial properties of the rhizospheres. The interactive effects of elevated CO2 and drought on plant growth and microbial properties significantly differed, indicating that elevated CO2 significantly alleviated the effects of drought stress on the microbial properties of the rhizosphere. In addition, the effects of elevated CO2 and drought on microbial biomass and enzymatic activities considerably varied between the two selected species. M. sativa generally experienced a better ameliorative effect than B. ischaemum.