Biochar--based soil amendment as an ecotechnology for restoration of salt affected soil:A case study in Shangqiu Henan,China

摘要

Salinity is the most extending land degradation problem in the arid and semi arid regions of theworld due to climate change and a severe environmental factor limiting the productivity ofagriculture.Currently, half of the world irrigated land resources and approximately 20％ of theagricultural land has been affected by salinity.Moreover, every year 1.5 million hectares ofproductive land severely affected by salinity and becomes unproductive.Accumulations of salts,particularly salts of sodium exert physiological threats to ecosystem, prevent normal metabolicfunctions, and hinder water absorption, nutrient uptake of the plant and soil biota.Salinity hasdrastic effects on plant, secondary effects of toxic salts causes injury of leaf cell, furtherreduces growth by specific ion toxicity.Salinity may also effects on the physical and chemicalproperties of soil, such a way increase soil compaction reduce the aeration.Thus, high levels ofsalts can dehydrate soil microbes and reduces soil microbial functions and nutrienttransformation.Considering all inferior effects of soil salinity a study was designed withbiochar based technology to reclaim salt-affected soil as a sustainable source for cropproduction and utilization of saline soil.
　　This study is to address the potential of using biochar-based technology to ameliorate saltstressed soil with a number of experiments on soil and plant health changes.A two-year fieldexperiment with soil amendment of biochar-poultry manure compost (BPC) and pyroligneoussolution (PS) was conducted in a moderately salt stressed Entisol from Central China.The soilwas amended with BPC at 12 t ha-1 following treatment with diluted PS solution at 0.15 t ha-1 1week before winter wheat sowing.Samples of topsoil (0-20 cm) were collected for thedetermination of detailed soil physical and chemical properties, bulk and maize rhizosphere soilwas collected for soil microbial community structure and soil enzymes activity.Plant sampleswere collected for major nutrient and sodium content in plant biomass while the yield of wheatand maize was measured when crop harvested.Plant samples for bio-molecules enzymes werecollected at vegetative growth stage of maize crop.
　　The detailed analysis of soil physical properties, leaching of salts from the root zone of crop,improvement in nutrient content in soil and plant biomass with the (BPC-PS) amendment anduntreated salt-affected soil were determined through adopted laboratory techniques.Scanningelectron microscopy (SEM) was used to examine the salt content in fresh and aged biocharparticles collected from the salt-affected field.Soil microbial biomass and enzymes weredetermined by usual method.Microbes in bulk soil and maize rhizosphere (bacterial and fungal)community structure and abundances were assessed by culture-independent moleculartechniques including polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real-time (qPCR), respectively.Moreover, important band retrievedfrom DGGE gel were analyzed using sequencing and phylogenetic analysis for further detailsof soil organisms.

目录

声明

Table of Contents

ABSTRACT

List of Abbreviations

Chapter 1 Introduction and Research Background

1．1 Rationale and working hypotheses

1．1．1 Objectives of the study

1．1．2 Research pathway or routines

1．2 The issue of saIt stressed soil and soil salinization

1．2．1 Soil salinity and salt affected soil

1．2．2 Salinity types and characterization

1．2．3 Saline soils

1．2．4 Sodie Soil

1．2．5 Saline Sodic soil

1．2．6 Major causes and current features of soil salinity

1．2．7 Adaptive measurement and mechanisms of salinity stress

1．3 Soil salinity effects on plant growth and health

1．3．1 Soil salinity and seed germination

1．3．2 Salinity stress and plant growth

1．3．3 Photosynthetic activity under salt-stress

1．3．4 Relationship between Salt stress and water

1．3．5 Salinity and plant nutrition

1．3．6 Salinity and crop yield

1．3．7 Technologies available for alleviating or desalting soil

Chapter 2 Effects of biochar-based amendment on reduction of soil salinity，nutrient improvement and wheat grain yield

2．1 Introduction

2．2 Materials and methods

2．2．1 Experiment site and Soil

2．2．2 Biochar and pyroligneous solution used

2．2．3 Biochar poultry manure compost(BPC)

2．2．4 Experiment design

2．2．5 Soil sampling and analysis

2．2．6 Wheat yield measurement

2．2．7 Statistical analysis

2．3 Results

2．3．1 Soil physical and chemical property

2．3．2 Soil Nutrient status

2．3．3 Wheat grain yield

2．4 Discussions

2．4．1 Mutual effects of BPC-PS on soil salinity

2．4．2 Effect of BPC-PS on soil nutrient supply and yield

2．5 Conclusions

Chapter 3 Effects of biochar-based amendment on maize growth and bio-molecules activity

3．1 Introduction

3．2 Materials and methods

3．2．1 Experimental site climate and Soil

3．2．2 Maize cultivation and fertilization

3．2．3 Soil sampling and analysis

3．2．4 Field observations and plant sampling

3．2．5 Determination of plant relative water content and electrolytes leakage(％)

3．2．6 Leaf chlorophyll content

3．2．7 Determination of proline and lipid peroxidation(MDA)

3．2．8 Soluble sugar，amino acids and ascorbic acids

3．2．9 Ion content in leaf sap of maize

3．2．10 Scanning electron microscopy of biochar particles

3．2．11 Statistical analysis

3．3 Results

3．3．1 Soil salinity and plant salt concentration with BPC-PS amendment

3．3．2 Improvement in plant growth

3．3．3 Plant nutrition and leaf bioactivity

3．3．4 Reaction of the biochar after added to soil

3．4 Discussion

3．4．1 Effect of the BPC-PS treatment on plant growth and soil properties

3．4．2 Effect of BPC-PS amendment on maize bioactivity and proline osmolyte

3．4．3 Salt absorption in biochar particles

3．5 Conclusions

Chapter 4 Effects of biochar-based amendment on nutrient uptake，biomass yield and crop quality

4．1 Introduction

4．2 Materials and methods

4．2．1 Experiment site climate and soil

4．2．2 Plant sampling and analysis

4．2．3 Protein content of maize grain

4．2．4 Grain yield and nutrient uptake

4．2．5 Disease infection and morphological characters

4．2．5 Statistical analysis

4．3 Results

4．3．1 Biomass production and grain protein content of maize crop

4．3．2 Nutrient uptake and translocation

4．3．3 Disease infection and grain morphological conditions

4．4 Discussion

4．4．1 Effects of amendment on crop growth and nutrient uptake

4．4．2 Effect of amendments on crop quality and grain yield

4．5 Conclusions

Chapter 5 Effects of biochar-based amendment on soil microbial community structure and enzymes activity

5．1 Introduction

5．2 Materials and methods

5．2．1 Experimental site climate and soil

5．2．2 Soil sampling and analysis

5．2．3 Determination of microbial biomass carbon and nitrogen

5．2．4 Soil enzymes activity measurement

5．2．5 DNA extraction and real-time quantitative PCR

5．2．6 Bacterial and fungal community analysis using DGGE

5．2．7 Phyiogenetic analysis and gene sequencing

5．2．8 DGGE profile analysis

5．2．9 Statistical analysis

5．3 Results

5．3．1 Soil Cmic，Nmic and soil enzyme activity

5．3．2 Bacterial and fungai gene abundance and community structure

5．3．3 Phylogenetic analysis

5．4 Discussion

5．4．1 Microbial biomass and diversity changes in BPC-PS treated salt soil

5．4．2 Changes in soil enzyme activity with BPC-PS

5．4．3 Soil microbial community structure

5．4．4 Year changes

5．5 Conclusions

Chapter 6 Findings，gaps and future perspective of the study

6．1 Major finding of the study

6．2 Gaps of the study

6．3 Future perspective

References

List of Publications

Project funding

Picture gallery

Acknowledgement