氮是植物生長需求最重要的元素之一,是農(nóng)業(yè)生產(chǎn)中影響作物產(chǎn)量最關(guān)鍵的限制因子,穩(wěn)定的有機(jī)碳(SOC)供應(yīng)對(duì)于植物的養(yǎng)分循環(huán)和改善土壤物理、化學(xué)和生物性質(zhì)(Rasool et al.2008),SOC因?yàn)槠浜妥魑锂a(chǎn)量之間的密切關(guān)系而成為土壤質(zhì)量的重要指標(biāo)(Lal 1997),本研究于2016-2017年在河南鄭州實(shí)施,目的是想得到在冬小麥-夏玉米耕作系統(tǒng)中5個(gè)氮肥施用梯度下的氮肥利用效率(NUE)和土壤肥力的關(guān)系。土壤處理在小麥季和玉米季都為五個(gè)不同的肥力梯度(非常低,低,中,高,非常高),每個(gè)處理都有4個(gè)重復(fù),采用隨機(jī)整組設(shè)計(jì)。結(jié)果顯示,相對(duì)非常低水平,較高的土壤肥力水平(高和非常高)可以在小麥和玉米季顯著提升作物產(chǎn)量、N吸收和NUE(小麥和玉米產(chǎn)量分別提升41-44%和98–105%,N吸收分別提高47%和116-123%,NUE分別提升18-23%和12%)(P<0.05)。在冬小麥和夏玉米季,小麥籽粒產(chǎn)量和土壤肥力之間呈線性關(guān)系(f=y0+a*x)(籽粒產(chǎn)量=a+b*SFL,a=(8.8733)x+11.49,r2:0.71,P=0.007)(圖3-9)。相似的線性關(guān)系在15...

【文章頁數(shù)】：109 頁

【學(xué)位級(jí)別】：博士

【文章目錄】：
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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