Exploring relations between plant photochemical quantum parameters and unsaturated soil water retention for biochars and pith amended soils

Himanshu Kumar; Suriya Prakash Ganesan; Huang Sang; Lingaraj Sahoo; Ankit Garg; Sreedeep Sekharan; Anthony K Leung

doi:10.1016/j.scitotenv.2021.150251

Exploring relations between plant photochemical quantum parameters and unsaturated soil water retention for biochars and pith amended soils

Sci Total Environ. 2022 Jan 15:804:150251. doi: 10.1016/j.scitotenv.2021.150251. Epub 2021 Sep 9.

Authors

Himanshu Kumar¹, Suriya Prakash Ganesan², Huang Sang³, Lingaraj Sahoo⁴, Ankit Garg⁵, Sreedeep Sekharan⁶, Anthony K Leung⁷

Affiliations

¹ Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear water Bay, Hong Kong Special Administrative Region. Electronic address: hkumar@connect.ust.hk.
² Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear water Bay, Hong Kong Special Administrative Region. Electronic address: spganesan@connect.ust.hk.
³ College of Civil Engineering and Architecture, Guangxi University, China.
⁴ Department of Bioscience and Bioengineering, Indian Institute of Technology, Guwahati, India. Electronic address: ls@iitg.ac.in.
⁵ Guangdong Engineering Center for Structure Safety and Health Monitoring, Department of Civil and Environmental Engineering, Shantou University, China. Electronic address: ankit@stu.edu.cn.
⁶ Department of Civil Engineering, Indian Institute of Technology, Guwahati, India. Electronic address: srees@iitg.ac.in.
⁷ Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear water Bay, Hong Kong Special Administrative Region. Electronic address: ceanthony@ust.hk.

PMID: 34798756
DOI: 10.1016/j.scitotenv.2021.150251

Abstract

Sustainable biomaterials such as natural fibers and biochars have been increasingly used in green infrastructures such as landfill covers for its dual-advantages of climate change mitigation and waste management. The existing studies did not systematically discuss the comparison on how biochar (stable carbon) and fiber (likely degradable), influence plant growth and water retention abilities in unsaturated soils. Also, the effect of photochemistry in the amended soils has rarely been investigated. This study addresses the limitations of previous investigations by exploring plant parameters such as photochemical yield, stomatal conductance, root area index, and unsaturated soil hydraulic parameters, including soil water retention curves (SWRC) of amended soils. Pot experiments were conducted in an environmentally controlled greenhouse. Two biochars from different plant-based feedstocks (Eichhornia crassipes, Prosopis juliflora) and one natural fiber (coir pith fiber) were mixed with soil at 5% and 10% application rate (by weight). Grass species of Axonopus compressus was planted to study the effects of different amendment materials and its corresponding plant responses during an applied drought period. The test results show that biochar amended soils increased the shoot growth by up to 100-200%. The stomatal conductance of the grass leaves increased by 54%-101% during the drought period for both biochars and coir amended soil. Furthermore, at low suction, the coir had a high water retention capacity than the biochars, explaining the observed higher stomatal conductance values. Importantly, it was discovered that the plant photochemical quantum yield responses associated with plant wilting was found to vary between 1500 and 1800 kPa for all the soil treatments. The study concludes with a newly developed mathematical expression based on the measurements of plant parameters and soil suction. The new equation could be used to optimize the irrigation frequency in order to apply any informed measures to maintain green infrastructures.

Keywords: Biomaterials; Photochemical yield; Plant growth; Soil suction; Stomatal conductance.

MeSH terms

Charcoal
Plant Development
Soil Pollutants* / analysis
Soil*
Water

Substances

Soil
Soil Pollutants
biochar
Water
Charcoal