Effects of organic vs. conventional management on soils
Thirteen organic (commercial and experimental) farms were selected randomly on different soil types throughout The Netherlands. Neighbouring conventional farms were selected under similar cropping on fields with the same soil type. All organic farms were accredited and, thus did not use chemical fertilizer, pesticides or genetically modified organisms for at least the last 2 years.
A healthy soil is defined as a stable system with resilience to stress, high biological diversity, and high levels of internal nutrient cycling (Van Bruggen and Semenov, 2000). In this study the effects of long-term organic management under Dutch conditions on soil health were researched and were determined by physical, chemical, and especially biological parameters of the soil.
The organic soils had a higher biodiversity in both nematodes (roundworms) and eubacteria and a higher biological activity in the soil. The reason for the higher diversity in the organic soil seems to be the lower plow depth and especially the use of the organic improvements and the absence of artificial fertilizer. This results in significantly lower levels of both nitrate and nitrogen and larger species richness in both bacteria and roundworms and higher numbers of bacteria in organic soils.
In conclusion organically managed soils on average are more stable systems with a larger soil health as defined by Van Bruggen and Semenov (2000).
> From: Diepeningen et al., Applied Soil Ecology 31 (2016) 120-135. All rights reserved to Elsevier B.V.. Click here for the online summary.