In this post in the Conversation, crop scientist Matthew Wallenstein, Associate Professor and Director at the Innovation Center for Sustainable Agriculture, Colorado State University, discusses the potential of natural microbes to improve agriculture and make it more sustainable. 

In this Nature commentary Jess Davies from Lancaster Environment Centre discusses the urgent need to deal with the degradation of our soils, focusing on the need for the private sector to take this sustainability threat seriously by taking action on soil. Today one-third of all soils and more than half of agricultural soils are moderately or highly degraded.

This review assesses the performance of organic cropping systems as an approach to sustainable agriculture, and seeks to identify the contextual considerations (such as type of cropping system) that may affect this performance. The scope of the review is constrained to the level of the farming system (i.e. excludes considerations of other components of the food system, such as packaging or transport). In order to provide an unbiased assessment of organic farming as a means of sustainable agriculture, rather than approaching the question from the usual “What does organic farming do well/badly?” angle, the authors ask “What constitutes successful sustainable agriculture?” then measure organic farming against this yardstick.

The Farm Carbon Cutting Toolkit (FCCT) has launched a crowdfunding campaign to support UK farmers in adopting Carbon Farming techniques. This approach aims to minimise carbon emissions and maximise carbon sequestration on farms, particularly in soils.

This article by agricultural researchers in Spain reviews the historical changes in land use and soil management practices, and examines how these changes have contributed to soil erosion in the past, before presenting modelling data to show how soil erosion may impact on agricultural yields in the future.

This paper in Nature addresses the question of whether a warming planet leads to increased CO2 emissions through heightened activity by soil microbes. It finds that this positive feedback mechanism exists and is likely to be of great importance in the future global carbon budget.

This paper by researchers in the US and Australia reports the findings of a long-term field-trial-based investigation into the effect of elevated carbon dioxide concentrations (CO2) on soy yield and drought tolerance. Their findings challenge the widely-held belief that crop yield will be increased by elevated CO2 (the so-called CO2 fertilisation effect) both because of increased photosynthetic rate, and because of lower susceptibility to drought: it has long been assumed that in higher CO2 conditions, stomatal conductance will be lower, leading to slower water loss from the leaves, slower water uptake from the roots, and consequently more moisture remaining in the soil for longer, thereby sustaining crops in limited rainfall.

This study compares real world observations of the age of carbon in soils, to soil carbon’s age as represented in earth system models that are used to make climate change projections. It then explores the implications of the results, by modelling expected future levels of carbon storage in global soils, occurring in response to increasing levels of atmospheric carbon dioxide. To illustrate the difference, modelled increases in soil carbon storage are contrasted both before and after updating earth systems models to reflect these real-world observations.

Alternative cropping systems such as organic or conservation agriculture are often expected to lead to enhanced soil carbon storage as compared with conventional systems, and therefore to hold potential to contribute to climate change mitigation via carbon sequestration.