潮土中氮素利用效率与土壤肥力的关系

发布时间：2023-04-25 05:38

　　氮是植物生长需求最重要的元素之一,是农业生产中影响作物产量最关键的限制因子,稳定的有机碳(SOC)供应对于植物的养分循环和改善土壤物理、化学和生物性质(Rasool et al.2008),SOC因为其和作物产量之间的密切关系而成为土壤质量的重要指标(Lal 1997),本研究于2016-2017年在河南郑州实施,目的是想得到在冬小麦-夏玉米耕作系统中5个氮肥施用梯度下的氮肥利用效率(NUE)和土壤肥力的关系。土壤处理在小麦季和玉米季都为五个不同的肥力梯度(非常低,低,中,高,非常高),每个处理都有4个重复,采用随机整组设计。结果显示,相对非常低水平,较高的土壤肥力水平(高和非常高)可以在小麦和玉米季显著提升作物产量、N吸收和NUE(小麦和玉米产量分别提升41-44%和98–105%,N吸收分别提高47%和116-123%,NUE分别提升18-23%和12%)(P<0.05)。在冬小麦和夏玉米季,小麦籽粒产量和土壤肥力之间呈线性关系(f=y0+a*x)(籽粒产量=a+b*SFL,a=(8.8733)x+11.49,r2:0.71,P=0.007)(图3-9)。相似的线性关系在15...

【文章页数】：109 页

【学位级别】：博士

【文章目录】：
摘要
ABSTRACT
CHAPTER 1 INTRODUCTION
    1.1 Nitrogen Use Efficiency
    1.2 Nitrogen mineralization
        1.2.1 Mechanism of nitrogen assimilation:
        1.2.2 Nitrate assimilation:
        1.2.3 Biotic immobilization–remineralization
        1.2.4 Abiotic Immobilization
        1.2.5 Soil organic nitrogen mineralization
        1.2.6 Gross and net N mineralization
        1.2.7 Soil N mineralization potential
        1.2.8 Factors affecting soil N mineralization
        1.2.9 Indexes of N mineralization
    1.3 Scientific Question
    1.4 Hypothesis
    1.5 Objectives
CHAPTER 2 MATERIALS AND METHODS
    2.1 Design or route map
    2.2 Site description,sampling
        2.2.1 Soil sample preparation for the analysis of basic properties
        2.2.2 Chemical and biological analysis of incubated and non-incubated soils
    2.3 Experimental setup
        2.3.1 Incubation study(N Mineralization)
        2.3.2 Pot experiment cropped with winter wheat and summer maize
    2.4 Chemical analysis
    2.5 Data processing and statistical analysis
CHAPTER 3 POT STUDY IN WINTER WHEAT“RELATION OF NUE WITH SOIL FERTILITY”
    3.1 Summary
    3.2 Introduction
    3.3 Results
        3.3.1 Crop yield
        3.3.2 Nitrogen uptake
        3.3.3 Nitrogen use efficiency
        3.3.4 Relationship between grain yield,NUE and soil fertility levels
        3.3.5 Chemical and biological changes in soil
    3.4 Discussion
        3.4.1 Crop yield
        3.4.2 Nitrogen uptake
        3.4.3 Nitrogen use efficiency
        3.4.4 Relationship between wheat grain yield and soil fertility levels,¹⁵NUE in wheat and soil fertility levels
        3.4.5 NUE links with N mineralization
        3.4.6 Chemical and biological changes in soil
CHAPTER 4 POT STUDY IN SUMMER MAIZE“RELATION OF NUE WITH SOIL FERTILITY”
    4.1 Summary
    4.2 Introduction
    4.3 Results
        4.3.1 Crop yield
        4.3.2 Nitrogen uptake
        4.3.3 Nitrogen use efficiency
        4.3.4 Relationship between grain yield,NUE and soil fertility levels
        4.3.5 Chemical and biological changes in soil
    4.4 Discussion
        4.4.1 Crop yield
        4.4.2 Nitrogen uptake
        4.4.3 Nitrogen use efficiency
        4.4.4 NUE links with N mineralization study
        4.4.5 Chemical and biological changes in soil
CHAPTER 5 NITROGEN SUPPLY FROM SOIL THROUGH MINERALIZATION
    5.1 Summary
    5.2 Introduction
    5.3 Results
        5.3.1 Changes in NH4
+-N and NO3
-N content in the soil during the incubation
        5.3.2 N mineralization potential and mineralization rate constant(k)
        5.3.3 Net N mineralization rate and cumulative N mineralization rate
        5.3.4 Availability of mineralized N to wheat and maize during the whole growing period
        5.3.5 The relationship between N mineralization rate and soil microbial biomass
        5.3.6 Temporal changes in mineralized N and fixed NH4+
        5.3.7 Nitrified nitrogen and k(constant)rate
    5.4 Discussion
        5.4.1 N mineralization process
        5.4.2 Fixation of mineralized NH4+
        5.4.3 The quantitative relationship between mineralization and nitrification
CHAPTER 6 CONCLUSION
REFERENCES
ACKNOWLEDGEMENTS
CURRICULUM VITAE



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