Agronomy and photosynthesis physiology of hemp (Cannabis sativa L.)

Kailei Tang

Research output: Thesisinternal PhD, WU

Abstract

Hemp (Cannabis sativa L.) is a sustainable high-yielding crop that delivers valuable fibres, seeds and psychoactive substances. However, there is a lack of field experimental data on the cultivation of hemp because its production was largely abandoned in the last century. Hemp is now considered as an ideal crop to produce innovative biomaterials, and in particular, the dual-purpose hemp production (fibre + seed) is now the norm in European countries, driven by the shift of a rapidly expanding market for hemp seeds coupled with lower quality fibre requirements for innovative biomaterials. This study brought new information on the agronomy and photosynthesis physiology for the resurging production of hemp, particularly for dual-purpose production in Europe.

The effects of important agronomic factors, i.e. cultivar, planting density, and nitrogen fertilization, on the performance of the hemp crop were investigated under contrasting European environments. Based on the experimental data, for dual-purpose hemp production, a planting density of 90–150 plants m-2 is recommended for a monoecious cultivar that gives a long vegetative phase while leaving enough time for seed growth. A nitrogen fertilization rate of 60 kg N ha-1 was generally sufficient in the tested environments whereas further optimization of nitrogen fertilization requires accurate and precise assessment of plant nutritional status. To facilitate assessing plant nutritional status, a critical nitrogen dilution curve was determined for hemp.

The responses of leaf photosynthesis to nitrogen content and temperature were quantified using a biochemical model of C3 leaf photosynthesis, based on a complete set of photosynthetic measurements for hemp leaves. Then, by combining measurements and modelling, an upscaling was made from the leaf to the canopy level to analyse hemp’s photosynthetic nitrogen-use efficiency (NUE) and water-use efficiency (WUE) in response to water and nitrogen supply. The effect of nitrogen supply level on hemp’s NUE and WUE was largely determined by its effect on canopy size or leaf area index (LAI). The effect of short-term water stress on WUE and NUE was reflected in the stomatal regulation, whereas long-term water stress enhanced leaf senescence, reduced LAI but retained total canopy nitrogen content, and thus resulted in a further increase in WUE.

Findings in this thesis provided an improved understanding of the agronomy and photosynthesis physiology of hemp, particularly in relation to the dual-purpose production of hemp in Europe. Such understanding not only provides additional evidence that hemp can be grown as a sustainable crop over a wide range of climatic and agronomic conditions, but also provides essential information for parameterizing crop growth models. Prospects for further research were discussed in view of using the findings in this thesis in combination with a crop growth model to develop strategies for optimization of hemp cultivation and breeding.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • Struik, Paul, Promotor
  • Yin, Xinyou, Co-promotor
  • Amaducci, S., Co-promotor, External person
Award date23 Mar 2018
Place of PublicationWageningen
Publisher
Print ISBNs9789463438841
DOIs
Publication statusPublished - 2018

Fingerprint

Cannabis sativa
hemp
agronomy
physiology
photosynthesis
water use efficiency
nutrient use efficiency
nitrogen
fertilization (reproduction)
biocompatible materials
crop models
leaves
canopy
crops
seeds
growth models
leaf area index
nitrogen content
nutritional status
water stress

Cite this

Tang, Kailei. / Agronomy and photosynthesis physiology of hemp (Cannabis sativa L.). Wageningen : Wageningen University, 2018. 174 p.
@phdthesis{c9f930855dd14df9aebd4f7d9163a564,
title = "Agronomy and photosynthesis physiology of hemp (Cannabis sativa L.)",
abstract = "Hemp (Cannabis sativa L.) is a sustainable high-yielding crop that delivers valuable fibres, seeds and psychoactive substances. However, there is a lack of field experimental data on the cultivation of hemp because its production was largely abandoned in the last century. Hemp is now considered as an ideal crop to produce innovative biomaterials, and in particular, the dual-purpose hemp production (fibre + seed) is now the norm in European countries, driven by the shift of a rapidly expanding market for hemp seeds coupled with lower quality fibre requirements for innovative biomaterials. This study brought new information on the agronomy and photosynthesis physiology for the resurging production of hemp, particularly for dual-purpose production in Europe. The effects of important agronomic factors, i.e. cultivar, planting density, and nitrogen fertilization, on the performance of the hemp crop were investigated under contrasting European environments. Based on the experimental data, for dual-purpose hemp production, a planting density of 90–150 plants m-2 is recommended for a monoecious cultivar that gives a long vegetative phase while leaving enough time for seed growth. A nitrogen fertilization rate of 60 kg N ha-1 was generally sufficient in the tested environments whereas further optimization of nitrogen fertilization requires accurate and precise assessment of plant nutritional status. To facilitate assessing plant nutritional status, a critical nitrogen dilution curve was determined for hemp. The responses of leaf photosynthesis to nitrogen content and temperature were quantified using a biochemical model of C3 leaf photosynthesis, based on a complete set of photosynthetic measurements for hemp leaves. Then, by combining measurements and modelling, an upscaling was made from the leaf to the canopy level to analyse hemp’s photosynthetic nitrogen-use efficiency (NUE) and water-use efficiency (WUE) in response to water and nitrogen supply. The effect of nitrogen supply level on hemp’s NUE and WUE was largely determined by its effect on canopy size or leaf area index (LAI). The effect of short-term water stress on WUE and NUE was reflected in the stomatal regulation, whereas long-term water stress enhanced leaf senescence, reduced LAI but retained total canopy nitrogen content, and thus resulted in a further increase in WUE. Findings in this thesis provided an improved understanding of the agronomy and photosynthesis physiology of hemp, particularly in relation to the dual-purpose production of hemp in Europe. Such understanding not only provides additional evidence that hemp can be grown as a sustainable crop over a wide range of climatic and agronomic conditions, but also provides essential information for parameterizing crop growth models. Prospects for further research were discussed in view of using the findings in this thesis in combination with a crop growth model to develop strategies for optimization of hemp cultivation and breeding.",
author = "Kailei Tang",
note = "WU thesis 6884 Includes bibliographical references. - With summary in English",
year = "2018",
doi = "10.18174/434837",
language = "English",
isbn = "9789463438841",
publisher = "Wageningen University",
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}

Tang, K 2018, 'Agronomy and photosynthesis physiology of hemp (Cannabis sativa L.)', Doctor of Philosophy, Wageningen University, Wageningen. https://doi.org/10.18174/434837

Agronomy and photosynthesis physiology of hemp (Cannabis sativa L.). / Tang, Kailei.

Wageningen : Wageningen University, 2018. 174 p.

Research output: Thesisinternal PhD, WU

TY - THES

T1 - Agronomy and photosynthesis physiology of hemp (Cannabis sativa L.)

AU - Tang, Kailei

N1 - WU thesis 6884 Includes bibliographical references. - With summary in English

PY - 2018

Y1 - 2018

N2 - Hemp (Cannabis sativa L.) is a sustainable high-yielding crop that delivers valuable fibres, seeds and psychoactive substances. However, there is a lack of field experimental data on the cultivation of hemp because its production was largely abandoned in the last century. Hemp is now considered as an ideal crop to produce innovative biomaterials, and in particular, the dual-purpose hemp production (fibre + seed) is now the norm in European countries, driven by the shift of a rapidly expanding market for hemp seeds coupled with lower quality fibre requirements for innovative biomaterials. This study brought new information on the agronomy and photosynthesis physiology for the resurging production of hemp, particularly for dual-purpose production in Europe. The effects of important agronomic factors, i.e. cultivar, planting density, and nitrogen fertilization, on the performance of the hemp crop were investigated under contrasting European environments. Based on the experimental data, for dual-purpose hemp production, a planting density of 90–150 plants m-2 is recommended for a monoecious cultivar that gives a long vegetative phase while leaving enough time for seed growth. A nitrogen fertilization rate of 60 kg N ha-1 was generally sufficient in the tested environments whereas further optimization of nitrogen fertilization requires accurate and precise assessment of plant nutritional status. To facilitate assessing plant nutritional status, a critical nitrogen dilution curve was determined for hemp. The responses of leaf photosynthesis to nitrogen content and temperature were quantified using a biochemical model of C3 leaf photosynthesis, based on a complete set of photosynthetic measurements for hemp leaves. Then, by combining measurements and modelling, an upscaling was made from the leaf to the canopy level to analyse hemp’s photosynthetic nitrogen-use efficiency (NUE) and water-use efficiency (WUE) in response to water and nitrogen supply. The effect of nitrogen supply level on hemp’s NUE and WUE was largely determined by its effect on canopy size or leaf area index (LAI). The effect of short-term water stress on WUE and NUE was reflected in the stomatal regulation, whereas long-term water stress enhanced leaf senescence, reduced LAI but retained total canopy nitrogen content, and thus resulted in a further increase in WUE. Findings in this thesis provided an improved understanding of the agronomy and photosynthesis physiology of hemp, particularly in relation to the dual-purpose production of hemp in Europe. Such understanding not only provides additional evidence that hemp can be grown as a sustainable crop over a wide range of climatic and agronomic conditions, but also provides essential information for parameterizing crop growth models. Prospects for further research were discussed in view of using the findings in this thesis in combination with a crop growth model to develop strategies for optimization of hemp cultivation and breeding.

AB - Hemp (Cannabis sativa L.) is a sustainable high-yielding crop that delivers valuable fibres, seeds and psychoactive substances. However, there is a lack of field experimental data on the cultivation of hemp because its production was largely abandoned in the last century. Hemp is now considered as an ideal crop to produce innovative biomaterials, and in particular, the dual-purpose hemp production (fibre + seed) is now the norm in European countries, driven by the shift of a rapidly expanding market for hemp seeds coupled with lower quality fibre requirements for innovative biomaterials. This study brought new information on the agronomy and photosynthesis physiology for the resurging production of hemp, particularly for dual-purpose production in Europe. The effects of important agronomic factors, i.e. cultivar, planting density, and nitrogen fertilization, on the performance of the hemp crop were investigated under contrasting European environments. Based on the experimental data, for dual-purpose hemp production, a planting density of 90–150 plants m-2 is recommended for a monoecious cultivar that gives a long vegetative phase while leaving enough time for seed growth. A nitrogen fertilization rate of 60 kg N ha-1 was generally sufficient in the tested environments whereas further optimization of nitrogen fertilization requires accurate and precise assessment of plant nutritional status. To facilitate assessing plant nutritional status, a critical nitrogen dilution curve was determined for hemp. The responses of leaf photosynthesis to nitrogen content and temperature were quantified using a biochemical model of C3 leaf photosynthesis, based on a complete set of photosynthetic measurements for hemp leaves. Then, by combining measurements and modelling, an upscaling was made from the leaf to the canopy level to analyse hemp’s photosynthetic nitrogen-use efficiency (NUE) and water-use efficiency (WUE) in response to water and nitrogen supply. The effect of nitrogen supply level on hemp’s NUE and WUE was largely determined by its effect on canopy size or leaf area index (LAI). The effect of short-term water stress on WUE and NUE was reflected in the stomatal regulation, whereas long-term water stress enhanced leaf senescence, reduced LAI but retained total canopy nitrogen content, and thus resulted in a further increase in WUE. Findings in this thesis provided an improved understanding of the agronomy and photosynthesis physiology of hemp, particularly in relation to the dual-purpose production of hemp in Europe. Such understanding not only provides additional evidence that hemp can be grown as a sustainable crop over a wide range of climatic and agronomic conditions, but also provides essential information for parameterizing crop growth models. Prospects for further research were discussed in view of using the findings in this thesis in combination with a crop growth model to develop strategies for optimization of hemp cultivation and breeding.

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DO - 10.18174/434837

M3 - internal PhD, WU

SN - 9789463438841

PB - Wageningen University

CY - Wageningen

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