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.
Integrating soil physical and biological properties in contrasting tillage systems in organic and conventional farming
Crittenden, S.J. ; Goede, R.G.M. de - \ 2016
European Journal of Soil Biology 77 (2016). - ISSN 1164-5563 - p. 26 - 33.
Earthworms - Non-inversion tillage - Organic agriculture - Soil physical quality - Structural equation modelling
Though soil physical and soil biological properties are intrinsically linked in the soil environment they are often studied separately. This work adds value to analyses of soil biophysical quality of tillage systems under organic and conventional farming systems by correlating physical and biological data otherwise left unexplored. Multivariate redundancy analysis was used to relate data on soil water, soil structure, soil carbon, crop yield, and earthworm species abundances (Aporrectodea caliginosa, Aporrectodea rosea, Eiseniella tetraedra, Lumbricus rubellus). Structural equation modelling was then used to infer causal relations amongst the variables. Effects of tillage system (i.e., mouldboard ploughing (MP) and non-inversion tillage (NIT)) on soil physical parameters and on the earthworm species Lumbricus rubellus were similar in organic and conventional farming. Despite sampling times in different seasons and different crops present at the time of sampling NIT correlated positively with L. rubellus, soil organic matter content, plant-available water content, soil aggregate stability, soil water content, and penetration resistance. Field-saturated hydraulic conductivity was negatively correlated with NIT and was negatively, or not correlated at all, with earthworm species abundances, possibly due to the absence of Lumbricus terrestris in these fields. In the comparison of organic fields, earthworms were positively correlated with the soil's ability to hold water but loosening by ploughing appears to have benefited the conduction of water through soil more than earthworms. Tillage systems and farming systems were found to have both direct and indirect influences on soil parameters. Organic farming increased soil organic matter content, soil water content, and both endogeic and epigeic earthworm species abundances. Non-inversion tillage increased crop yield, soil organic matter content, and soil penetration resistance. This study demonstrates that multivariate techniques can integrate and add value to data otherwise analysed separately.