China: A Virtual Centre for Monitoring the Rhizosphere

Lead Research Organisation: Rothamsted Research
Department Name: Sustainable Agriculture Sciences-H

Abstract

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Description Year 1
Plant roots release various organic materials that may change soil structure and modify heat and mass transfer processes. Paired soil samples were mixed with distilled water and synthetic root exudates (Paterson et al., 2007) at a bulk density of 1.61 g cm-3 and a water content of 0.13 g g-1, packed into cylinders, and then incubated for 7 days at 17±1°C and a relative humidity of 90%. The samples then went on a drying process, and the changes of soil penetrometer resistance and thermal conductivity were monitored continuously. No difference in soil bulk density was observed between the samples treated with water and root exudates. However, the soil samples with root exudates had significantly greater penetrometer resistance (10-900 kPa) and thermal conductivity (about 0.1-0.6 W m-1 K-1) than the water-only samples. The root exudates might have acted as binding agents, which increased soil strength and heat conduction by enhancing the contacts among soil particles.
Year 2
Rothamsted has hosted one short visit by Prof Gao to set up a system to measure soil density. In addition we have published an opinion paper in "Trends in Plant Science", which considers the relation ship between roots and soil structure.

Xin Wang from CAU is the middle of a 12 month visit to Rothamsted to measure the effects of rhizosphere conditions on root and shoot growth. Xin has identified an interaction between phosphorus availability and root impendence; both root impedance and phosphorous availability stunt root and shoot growth, but the effects are not additive.

In joint work on soil structure with Prof Gao we have found that biochar can alter the cracking pattern and shrinkage characteristics of lime concretion black soil. However, the e?ects of biochar on the shrinkage of lime concretion black soil are dependent on the number of wetting and drying cycles. This has important implication for soil-root interactions.

Year 3

We have submitted an opinion paper on the "Contribution of the heterogeneous rhizosphere to sustainable farming " to Trends in Plant Science. This paper concludes

"The current rhizosphere research and applications have encountered bottlenecks, but there are opportunities to break through. Future rhizosphere research needs to understand the root-soil interactions in an integrated manner with consideration of heterogeneity. The heterogeneity in soil structure and resource distribution is crucial for better understanding how to integrate the rhizosphere knowledge with the farming practices. Rhizosphere studies focusing on a single process without considering the complexity of soil heterogeneity can limit our ability to understand root-soil interactions. For the plant, one challenge is to understand the integration of the multiple sensing processes occurring in the rhizosphere. Exploring the key molecular components integrating multiple rhizosphere sensing pathways could be a most important future research objective. Moreover, the root-soil interactions are bi-directional and dynamic processes. Thus, non-invasive, real-time, and in situ investigations of rhizosphere processes are urgently required. Interdisciplinary approaches are urgently needed to further integrate plant biology and soil science to better explore root function and soil modification in rhizosphere processes. Exploring integrated root-soil interactions in the heterogeneously structured rhizosphere can provide us with a potential strategy to achieve rhizosphere engineering to increase nutrient use efficiency, crop productivity and below ground carbon sequestration for more sustainable production."

A paper has just been accepted in Geoderma. We have proposed an approach to estimate soil penetrometer resistance using measured water content, shear wave velocity and soil bulk density, which can be implemented with sensors buried in the soil. Having established the scientific and technical feasibility of using sensed water content, shear wave velocity and soil bulk density to estimate penetrometer resistance, the next stage will be to develop a field deployable sensing system. This will have the distinct advantage that matric potential, which is needed by existing models of penetrometer resistance, will not need to be measured. We will seek joint funding with CAU to continue this research.

We submitted a paper "Wheat growth responses to soil mechanical impedance are dependent on phosphorus supply" to Soil and Tillage Research by Wang et al. We found that mechanical impedance reduced wheat shoot and root growth under sufficient P supply, whereas under low P supply the effects of mechanical impedance on wheat growth were restricted. Shoot and root biomass, tiller number, leaf elongation, and nodal root number were significantly decreased in impeded plants under HP supply but not under LP supply, suggesting that wheat growth restriction in response to mechanical impedance is dependent on P supply. The contrasting responses to mechanical impedance under different P supply indicate an evident interaction between mechanical impedance and P supply. These findings providing new insights into the integrated adaptation of plants to both soil physical and nutritional stresses, implying the need to consider coupling of soil physical and nutritional management in agricultural practice.
Exploitation Route We hope that we will develop new proposals within this project to take the work forward. The project will benefit others from the papers we publish and from the new contacts we make.
Sectors Agriculture, Food and Drink

 
Description We held the start-up project workshop at the CAU campus in Beijing on 31/07-02/08/2017. The entire project team was present including Delta-T Devices who supported the initial project proposal. Outcomes: 1. We have established a soil column system to screen crop cultivars for their ability to take up nitrate. 2. We constructed an instrumented rhizotrons at RRes. They included ERT imaging (Binley, Lancaster), soil density measurement (Ren, CAU) and we grew wheat with a visiting student from Shen's group and Ren's group ( both CAU). This work was shown at the "Rothamsted Festival of Ideas" public event at RRes (23-24/06/2018). 3. Zhang (CAU) received the Chinese Scholarship Scheme, and spent 18 months with Whalley's soil physics group at RRes. This exchange has been made possible by this Partnering Award. We have just had a paper accepted in Geoderma. We proposed an approach to estimate soil penetrometer resistance using measured water content, shear wave velocity and soil bulk density, which can be implemented with sensors buried in the soil. Having established the scientific and technical feasibility of using sensed water content, shear wave velocity and soil bulk density to estimate penetrometer resistance, the next stage will be to develop a field deployable sensing system. This will have the distinct advantage that matric potential, which is needed by existing models of penetrometer resistance, will not need to be measured. 4. Weida Gao (CAU) visited RRes in December 2018 to develop ideas on measuring soil structure. 5. The team submitted an outline proposal for the GCRF Hubs call. Unfortunately, this did not progress to stage 2. 6. Gregory (RRes) attended a Workshop on Green Development in Agriculture at CAU (23-27/04/2018), in part organised by Shen (CAU), to continue collaborations in rhizosphere research. 7. Rothamsted hosted Xin Wang (CAU) to investigate the role of root-shoot signalling in response to abiotic stress sensed by the root. In this project we collabrated with the Institute of Experimental Botany & Palacký University, ┼álechtitelu 27, CZ-78371 Olomouc, Czech Republic to obtain a global hormone profile which was compared witn RNAseq data. This is now been prepared for publication. 8. We submitted a paper "Wheat growth responses to soil mechanical impedance are dependent on phosphorus supply" to Soil and Tillage Research by Wang et al. We found that mechanical impedance reduced wheat shoot and root growth under sufficient P supply, whereas under low P supply the effects of mechanical impedance on wheat growth were restricted. Shoot and root biomass, tiller number, leaf elongation, and nodal root number were significantly decreased in impeded plants under HP supply but not under LP supply, suggesting that wheat growth restriction in response to mechanical impedance is dependent on P supply. The contrasting responses to mechanical impedance under different P supply indicate an evident interaction between mechanical impedance and P supply. These findings providing new insights into the integrated adaptation of plants to both soil physical and nutritional stresses, implying the need to consider coupling of soil physical and nutritional management in agricultural practice. 9. We held a workshop at Rothamsted in October 2019 with the following: Andy Binley (Lancaster), Tony Miller (JIC), Tusheng Ren (CAU), Andy Gregory ( Rothamsted), Richard Whalley (Rothamsted), Wencan Zhang (CAU), Xin Wang(CAU), Guillaume Blanchy (Lancaster), Weida Gao (CAU), Kamrun Suravi (Rothamsted), Kemo Jin (CAU), Di Wang (Rothamsted), Peter Hedden (Rothamsted),Shahram Taherzadeh (Open University), Xiaoxian Zhang (Rothamsted), Ian Dodd (Lancaster), Dick Jenkins (Delta-T), Martin Goodchild (Delta-T) and Wenying Zhang (CAAS). 10. We have been invited to write an option article "The contribution of plant responses in a heterogeneously structured rhizosphere to sustainable farming" for Trends in Plant Science.
First Year Of Impact 2019
Sector Agriculture, Food and Drink
Impact Types Societal

 
Description GCRF-IAA investments
Amount £9,000 (GBP)
Funding ID S6168 
Organisation Rothamsted Research 
Sector Academic/University
Country United Kingdom
Start 02/2018 
End 02/2018
 
Description Strenghtened community links between UK and China 
Organisation Delta T Devices Ltd
Country United Kingdom 
Sector Private 
PI Contribution This project is highly synergistic with Designing Future Wheat Project (BBSRC) and the ASSIST project (NERC/BBSRC). We are contributiing expertise on soil physicla measurements and root growth.
Collaborator Contribution Professor Ren (CAU, Beijing) works on sensors for soil heat, water, density, and water flux, Professor Shen (CAU, Beijing) works on root responses to soil nutrient conditions Dr. Miller (JIC) works on soil nutrient sensing technology, Professor Binley (Lancaster) has been applying geophysical methods to sense the rhizosphere conditions, Dr. Whalley (RRes) works on the measurement of matric potential of soil water, measurement and monitoring of soil penetrometer resistance. Dick Jenkins (Delta-T devices) attended the start-up workshop and supplied water content sensors to the project
Impact 1. Outline proposal to GCRF hub call. 2. A poster at the "International Workshop of Soil Physics and the Nexus of Food, Energy and Water", which was held in Shenyang, China in August 2017. "Soil Thermal Conductivity and Penetrometer Resistance in Rhizosphere and Bulk Soil" 3. Ms Wencan Zang has won a Chinese Scholarship to spend 18months at Rothamsted. 4. Xin Wang, a PhD student from China Agriculture University, has been researching the effects of the rhizosphere conditions on root and shoot elongation at Rothamsted. This placement was party funded by this partnering award, China Agriculture University and project BBS/OS/NW/000004
Start Year 2017