J. Jpn. Soc. Soil Phys.
土壌の物理性No. 156, p.3 ∼ 5 (2023)

Advancing your career in soil physics

Tusheng REN

It is my pleasure to accept Dr. Yuki Kojima’s invitation of writing an article for the Journal of Japanese Society of Soil
Physics, focusing on encouraging young scientists to engage in soil physics and to advance their career. Although I read
only a few papers (from Prof. Kosuke Noborio) of this journal, I have a high respect on it because to my knowledge,
this is the only journal in the world specializing in the discipline of soil physics and it has already published 155 volumes
in the 65-year history (four years older than me!). In the following I put together a few pieces of advice based on theexperiences and challenges during my early time of soil physics research.
Actively integrate into the new community
For young scholars who have just embarked on the academic path, the ﬁrst challenge is how to integrate into the newcommunity, which may require an adjustment of the research direction. During the postgraduate studies, you deﬁned theresearch topic and completed your studies by working together with your supervisor and committee members. You may
need to make adjustment or even change the focus of your research to meet the requirements of the new institute. As ateam member, it is important to actively communicate and negotiate with the program leader, and to decide your research
topic that ﬁts to the overall direction of the team without losing your own values and long-term goals. In this process, it isworthy to seek guidance from senior professors with rich experience and deep academic achievements. If your study areaaligns with their interests in some way, it is good to seek their support and/or look for cooperative research work withthem.
Follow the rhythm of scientiﬁc research
Like the evolution of living things, the process of scientiﬁc research has its own rhythm. For an early career researcher,
you have a small group and your resource for doing research is very limited. At this stage, in addition to teaching, you arerequired to spend much of the time on writing proposals, recruiting students, equipping the laboratory, and looking foropportunities and roles that are beneﬁcial to your career. This can lead to a huge amount of stress in the day-to-day life. Insuch case, it is advisable to keep the early research work on relatively narrow topics that demand less resources. With thegrowth of research team and buildup of laboratory facilities after a few years, you may consider extending the research
program to more complicated ﬁeld studies and combining theoretical work with applied issues. In my ﬁrst 3 to 4 years
at China Agricultural University, I had 1–2 graduate students, the laboratory was essentially empty, and the only support
came from a program funded by the Natural Science Foundation of China (NSFC). Thus, I had to limit my research mainlyon improving the thermo-TDR technology for measuring soil thermal properties, water content, electrical conductivity,and water ﬂux (e.g., Ren et al., 2005; Gao et al., 2006; Lu et al., 2007; Ju et al., 2008), which was basically a continuationof my postdoc research at Iowa State University. A few years later, with the support of two national projects and another
NSFC program, my group had been expanded to 6-8 students and the laboratory facilities were updated signiﬁcantly.
Then I was able to start long-term ﬁeld studies in Northeast China and the North China Plain, where the thermo-TDR
technology was applied to monitor in situ soil thermal and hydraulic properties and processes, e.g., soil bulk density,
surface energy balance, dynamics of evaporation and transpiration, and thermal and hydraulic properties of frozen soils(Liu et al., 2008; Lu et al., 2008; Du et al. 2009; Du et al. 2010; Zhang et al. 2012; Du et al. 2013; Liu et al. 2014; Zhanget al., 2014; Peng et al. 2015; Tian et al. 2016; Peng et al., 2017; Wang et al., 2017). More recently, we have extended
the application of thermo-TDR technology further to the real world, e.g., monitoring in situ soil water retention curves
Department of Soil & Water, China Agricultural University, Beijing, China.

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第 154 号(2023)

during welting/drying processes and quantiﬁcation of soil structure and hydrothermal processes in the root zone (Zhanget al., 2018; Fu et al. 2020; Fu et al. 2021; Huang et al., 2021; Liu et al., 2023), which are rarely touched in traditionalsoil physics.
It is important to note that conduction of academic research is like running a marathon, one needs determination to reachthe ﬁnish line. Young scholars are full of vigor, often interested in many topics of various ﬁelds, and are anxious to act
immediately, but they are prone to make the mistake that treats all topics equally. While it is useful to broaden knowledge
and build professional network, working on parallel topics simultaneously may degrade the ﬁgure of your academic
integrity. You may consider broadening your research and working on different programs after you become more senior.
In the past 20 years, I have led and participated in 13 national research programs in the ﬁelds of soil structure, ﬁeld waterbalance, farming system, and soil-crop root interaction, the focus of my research, however, has primarily been on thequantiﬁcation of soil hydrothermal properties and processes under either laboratory or ﬁeld conditions.
Establish your own academic network and expand your visibility
For young scholars, it is of vital importance to build an academic network by participating in national and international
conferences, organizing scientiﬁc workshops, communicating with peers, and providing social service (e.g., as society
members, journal editors, and program coordinators). Academic network provides you the opportunity to present yourresearch results and lets more people know you, which is essential for establish good cooperation links. Through academic
networking, you can also follow what others are doing, obtain useful information, learn more about funding channels, andobtain the evaluation of your research work by others. In my early academic years, I served as the deputy director of theChinese Society of Soil Physics for 8 years, organized several national soil physics meetings, and did my best to attend
the ASA-CSSA-SSSA International Annual Meeting and the ISTRO Congress every year. I also served as editors andassociate editors for the Soil Science Society of America Journal, Agronomy Journal, Canadian Journal of Soil Science,and Soil Use and Management, from which I learned a lot from others and met many new colleagues. In addition, Iestablished long-term working relationships with Dr. Robert Horton of Iowa State University, Dr. Rainer Horn of the Kiel
University, Dr. Joshua Heitman of North Carolina State University, Dr. Tyson Ochsner of Oklahoma State University,and Dr. Richard Walley of the Rothamsted Research through joint research programs, student training, exchange visit,and joint publication of scientiﬁc papers. which has been of great help in the academic growth of myself and my graduate
students.
Leave time for thinking and reﬂection
Have you ever estimated your time distribution among daily issues (e.g., teaching, lab work, meeting, and short-termdeadlines), reference reading, self-learning, and independent thinking? I must admit that much of my daily time is spenton preparing proposals, writing reports, reviewing manuscripts, ﬁlling all kinds of forms, and unexpected interruptions,and there is always a shortage of time for reading new references and thinking independently. In today’s ﬁerce competitive
world of research, time management can make a big difference between progress and retreat. In my experience, the key
issue is to free enough time for creative thinking and reﬂection independently. After a period of busy and intense work,
make an appointment with yourself, get out of the pressure and exhaustion by thinking and reﬂection in silence, which isvery useful for capturing new knowledge, generating inspiration, ﬁne-tuning emotion, and recognizing your strengths andweaknesses more clearly.

References

Du, Z., Ren, T. and Hu, C. (2010): Tillage and residue removal effects on soil carbon and nitrogen storage in the North China Plain.
Soil Sci. Soc. Am. J., 74: 196–202.
Du, Z., Liu, S., Li, K. and Ren, T. (2009): Soil organic carbon and physical quality as inﬂuenced by long-term application of residue
and mineral fertiliser in the North China Plain. Aust. J. Soil Res., 47: 585–591.
Fu, Y., Lu, Y., Heitman, J. and Ren, T. (2020): Root-induced changes in soil thermal and dielectric properties should not be ignored.
Geoderma, 370: 114352.
Fu, Y., Lu, Y., Heitman, J. and Ren, T. (2021): Root inﬂuences on soil bulk density measurements with thermo-time domain
reﬂectometry. Geoderma, 403: 115195.
Gao, J., Ren, T. and Gong, Y. (2006): Correcting wall ﬂow effect improves the heat-pulse technique for determining water ﬂux insaturated soils. Soil Sci. Soc. Am. J., 70: 711–717.

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5Huang, X., Wang, H., Zhang, M., Horn, R. and Ren, T. (2021): Soil water retention dynamics in a Mollisol during a maize growing
season under contrasting tillage systems. Soil Till. Res., 209: 104953.
Ju, Z., Ren, T. and Horton, R. (2008): Inﬂuences of dichlorodimethylsilane treatment on soil hydrophobicity, thermal conductivity,and electrical conductivity. Soil Science, 173(7): 425–432.
Liu, L., Lu, Y., Horton, R. and Ren, T. (2023): Determination of soil water retention curves from thermal conductivity curves,texture, bulk density, and ﬁeld capacity. Soil Till. Res., 237: 105957.
Liu, X., Lu, S., Horton, R. and Ren, T. (2014): In situ monitoring of soil bulk density with a thermo-TDR sensor. Soil Sci. Soc. Am.
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Liu, X., Ren, T. and Horton, R. (2008): Determination of soil bulk density with thermo-time domain reﬂectometry sensors. Soil Sci.
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Lu, S., Ren, T., Gong, Y. and Horton, R. (2007): An improved model for predicting soil thermal conductivity from water content atroom temperature. Soil Sci. Soc. Am. J., 71: 8–14.
Lu, S., Ren, T., Gong, Y. and Horton, R. (2008): Evaluation of three models that describe soil water retention curves from saturation
to oven dryness. Soil Sci. Soc. Am. J., 72: 1542–1546.
Peng, X., Wang, Y., Heitman, J., Ochsner, T., Horton, R. and Ren, T. (2017): Measuring surface soil heat ﬂux with a multi-needle
heat-pulse probe. Euro. J. Soil Sci., 68: 336–344.
Peng, X., Heitman, J., Horton, R. and Ren, T. (2015): Field evaluation and improvement of the plate method for measuring soil heatﬂux density. Agric. Forest Meteo., 214–215: 341–349.
Ren, T., Ju, Z., Gong, Y. and Horton, R. (2005): Comparing heat-pulse and time domain reﬂectometry soil water contents fromthermo-time domain reﬂectometry probes. Vadose Zone J., 4: 1080–1086.
Tian, Z., Lu, Y., Horton, R. and Ren, T. (2016): A simpliﬁed de Vries-based model to estimate thermal conductivity of unfrozen andfrozen soil. Euro. J. Soil Sci.,doi:10.1111/ejss.12366.
Wang, Y., Ochsner, T., Heitman, J., Horton, R., Xue, X. and Ren, T. (2017): Weighing lysimeter data conﬁrm the accuracy andprecision of the heat-pulse technique for measuring daily soil evaporation. Soil Sci. Soc. Am. J., 81: 1074–1078.
Zhang, M., Lu, Y., Heitman, J., Horton, R. and Ren, T. (2018): Temporal changes of soil water retention behavior as affected bywetting and drying following tillage. Soil Sci. Soc. Am. J., 81: 1288–1295.
Zhang, X., Heitman, J., Horton, R. and Ren, T. (2014): Measuring near-surface soil thermal properties with the heat-pulse method:correction of ambient temperature and soil–air interface effects. Soil Sci. Soc. Am. J., 78: 1575–1583.
Zhang, X., Lu, S., Heitman, J., Horton, R. and Ren, T. (2012): Measuring subsurface soil-water evaporation with an improved
heat-pulse probe. Soil Sci. Soc. Am. J., 76: 876–879.