Agricultural practices indirectly influence plant productivity and ecosystem services through effects on soil biota

Abstract

Abstract. It is well established that agricultural practices alter the composition and diversity of soil microbial communities. However, the impact of changing soil microbial communities on the functioning of the agroecosystems is still poorly understood. Earlier work showed that soil tillage drastically altered microbial community composition. Here we tested, using an experimental grassland (Lolium, Trifolium, Plantago) as a model system, whether soil microbial communities from conventionally tilled (CT) and non-tilled (NT) soils have different influences on plant productivity and nutrient acquisition. We specifically focus on arbuscular mycorrhizal fungi (AMF), as they are a group of beneficial soil fungi that can promote plant productivity and ecosystem functioning and are also strongly affected by tillage management.Soil microbial communities from CT and NT soils varied greatly in their effects on the grassland communities. Communities from CT soil increased overall biomass production more than soil communities from NT soil. This effect was mainly due to a significant growth promotion of Trifolium by CT microorganisms. In contrast to CT soil inoculum, NT soil inoculum increased plant phosphorus concentration and total plant P content, demonstrating that the soil microbial communities from NT fields enhance P uptake. Differences in AM fungal community composition resulting, for instance, in twofold greater hyphal length in NT soil communities when compared to CT, are the most likely explanation for the different plant responses to CT and NT soil inocula.A range of field studies have shown that plant P uptake increases when farmers change to conservation tillage or direct seeding. Our results indicate that this enhanced P uptake results from enhanced hyphal length and an altered AM fungal community. Our results further demonstrate that agricultural management practices indirectly influence ecosystem services and plant community structure through effects on soil biota.

Understanding and Enhancing Soil Biological Health: The Solution for Reversing Soil Degradation

“…Tillage represents a disturbance of the soil habitat and can mechanically disrupt filamentous organisms, decrease soil structure, temporarily increase organic matter decomposition, and alter water and nutrient content and distribution [143,144]. Tillage-induced disturbance often has a negative impact on soil biota and the services that they supply [144][145][146]. Tillage most noticeably impacts large soil biota like earthworms [144] and filamentous organisms like fungi, particularly AM fungi [147].…”

Contribution of organic farming to public goods in Denmark

“…Surface dwelling earthworms and soil microarthropodes are negatively influenced in number and species diversity by mechanical soil cultivation, especially ploughing (Crittenden et al 2015;Ernst and Emmerling 2009;Peigné et al 2009). Tests in other countries have shown that ploughing reduces the biodiversity of arbuscular mycorrhiza in the soil (Köhl et al 2014;Säle et al 2015), and the fields in rotation are generally ploughed more in organic than in conventional agriculture. However, research has shown that the diversity of microorganisms is higher in soils with organic compared to conventional production (Oehl et al 2004;Stagnari et al 2014), so other factors may have greater influence on the soil biodiversity than ploughing.…”

Arbuscular mycorrhizal fungal dynamics following change of land use from mature forest to Eucalyptus plantation

“…Soil disturbances can disrupt the existing mycorrhizal network that connects mycorrhizae and plants together (Sheng et al, 2012;Kohl et al, 2014). Once disturbed, the AMF network will take a long time to restore back to its original state.…”