BBSRC study highlights cover crop benefits for soil health

The farming industry is coming under unprecedented pressure as the population grows and climate change threatens our world. Farmers need to produce more crops using fewer resources while remaining profitable. To help with this challenge, write Professor Wilfred Otten and Dr Csilla Hudek, the unique soil health facilities at Cranfield brings together businesses and universities to develop cutting-edge innovations.

Study Title: Improving Soil Health – Using Roots to Bioengineer Soils

Challenge: In order to sustainably increase crop yields to feed the growing world population – and considering the challenges we are facing today due to climate change – we need to carefully manage our soil resources. Promoting measures to manage soils better while reducing costs will also help farming businesses remain competitive and profitable. Instead of burning fossil fuels to drag more steel through the ground, this research will harness the power and properties of plant roots to engineer soil for optimised crop growth and improved soil health.

Methodology: Cover crops are a way for UK growers to improve soil health by maintaining minimum soil cover, thus minimising the land management required to limit erosion and maintain organic matter levels. They are fast-growing species, planted between two cash crops, which have the ability to boost soil health and reduce the negative impact of agro-management on the environment. In this BBSRC funded project we ask the question how best to exploit root traits of cover crops to improve soil health.

Different cover crops have different root traits, so they bring different benefits to soil. Recent studies demonstrated their important effects on several single soil functions such as aggregate stability and water availability. To date, no study has looked at the effects of root properties of cover crops to synergistically enhance multiple soil functions and no study has provided a robust methodology to combine complementary root traits in plant communities and to model their effects on multiple soil functions.

Roots improve soil because they can bind soil particles together, providing resistance against soil erosion by water. Roots can also improve soil infiltration and hence prevent runoff. Roots absorb and release nutrients into the soil, allowing soils to improve their nutrient status and to reduce environmental side-effects of intensive farming practices. Last but not least, roots break up the soil and create pore spaces when they decay. These macro-pores aerate the soil and make its structure crumblier. So, roots can act as a surrogate for machinery and hence reduce the number of tillage operations.

Root screening was performed and seven cover crop species (oat, rye, buckwheat, vetch, radish, mustard and phacelia) were grown in the large CHAP soil monoliths (1m3) with a sandy-clay loam soil at predefined structural conditions and wetness maintained through automated irrigation. The plants were grown in different environments prone to soil degradation. A series of root properties (e.g. rooting depth, root hair density) was determined, and a DNA technique, qPCR, was used to determine the proportions of root biomass of each species within a plant community.

Following the trials selected treatments are being tested in the field with project partner ADAS. The project will run till January 2021.

The trial is conducted in the Crop Health and Protection Centre’s Phenotyping and Soil Health Facility located at Cranfield University, which brings the latest scientific knowledge and understanding to 21st century farming. This Capability is unique in allowing precision control and monitoring of soil, water, crop and climate conditions under a range of tillage operations at pilot scale. Supported by a leading team of soil and crop scientists this enables farmers and Agri-Tech companies to develop and test innovative technologies to improve soil and crop health at pilot scale and evidence technologies designed to improve soil health.

Conclusion: The CHAP Soil Health Facility played a pivotal role in the screening of root traits that would allow for the optimal selection of mixtures of cover crop species to bring maximum benefit to soil health by evidencing the effect on multiple soil functions. Early results indicate that total root length and root surface area improve aggregate stability and soil porosity, and that fine roots penetrating the soil are more beneficial for creating pore space than thick taproots.

The key deliverable of this research will be a novel model that will allow the design of combinations of plant species with complementary root traits that prevent soil erosion, mitigate runoff and improve soil structure and nutrient status for optimised crop growth.

Wilfred Otten is Professor of Soil Biophysics at Cranfield University’s Soil and Agrifood Institute (CSAFI), which hosts the CHAP Phenotyping and Soil Health Facility. Dr Csilla Hudek is a Research Fellow in Modelling Root Traits to Bio-engineer Soil, also at CSAFI.

For more information go to our Phenotyping and Soil Health Facility and Soil Health Solution pages. For more details on this study go to Using Roots to Bio-engineer Soil for more details on the project; or visit YouTube for a brief overview of the Phenotyping and Soil Health facilities.


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