拖拉机行走引起的土壤压实对小麦和玉米生长的影响

论文摘要

当土壤颗粒被挤压到一起时就会产生的土壤压实,从而使土壤颗粒间的空隙减少。重型机器、车轮、耕作设备、动物的踩踏、有机物缺乏、频繁使用化肥以及多年耕深不变等都会导致土壤压实。土壤压实信息经常可以从其上面生长的作物状态来观察出。迟缓的出苗、纤细的秸杆、不一致的早期生长、较小的穗头、奇异的根系状态以及养分的减少吸收都是土壤压实的表现。过多的土壤压实会阻碍根系生长进而会限制根系在土壤中的发育程度。土壤压实是一个世界性问题,在中国目前对此问题研究较少。因此,本项目旨在研究土壤压实对土壤性质、作物生长的影响,同时探索适宜的改善土壤次表层压实的有效措施。在南京农业大学江浦实验农场,于2005-06进行了2种类型的实验,并在2006-07年重复了一次。第一种类型实验研究了表层土壤压实对作物生长的影响,第二类实验研究了改善下表层土壤人为压实的措施。其中,在第一类实验中设计了4个处理组,手扶式拖拉机、轮式拖拉机、履带式拖拉机压实1次为T1,压实2次为T2,压实4次为T3,对照组为T4。压实的次数可以反映压实的程度。压实后,用旋耕方式重新对表层的5厘米深土壤进行翻耕,小麦的品种为南京-601,而玉米的品种为白玉-109。在第二类实验中,根据播种计划对各实验小区使用了不同的改善措施。实验中共包括五种处理,其中S1为深耕（D.P.）,S2为D.P.+厩肥（10000 kg/ha）,S3为D.P.+硫酸钙（2000 kg/ha）,S4为D.P+厩肥（10000 kg/ha）+硫酸钙（2000 kg/ha）,S5为对照组。所有实验组中,对次表层土壤用手扶拖拉机行走4次、轮式拖拉机行走2次、履带式拖拉机行走2次的方式进行压实。然后,除对照组外,对各小区深耕15厘米。所有实验组中,小麦的品种为南京-601,播种量为236 kg/ha。在第一类实验中,土壤压实显著影响了表层土壤强度、容重、空隙度,作物的拔节时间、成熟时间、秸杆高度、每平方米穗数、每穗粒数、千粒重、生物质产量、产量、收获指数、作物生长率、根系长度、谷物蛋白质含量、植株中N、P、K含量。同时,照各处理两年的平均值来计,土壤压实对出苗时间、出苗率、每平方米分蘖数,上表层土壤强度、容重、空隙度、总N、有效P、有效K等参数没有显著影响。除下表层的土壤容重外,这些参数值在T4组中最大,在T3组中最小,而对下表层土壤容重来说,刚好相反。随着下表层土壤压实程度的增加,几乎所有的参数都有所增加。年份与压实间的交互影响作用不确定。这些参数的明显不同主要是压实导致土壤特性的改变而引起的。不过,与第一年相比,由于气候原因,这些参数值在第二年略有增加。主要是第一年中的平均最高温度和最低温度都小于第二年,结果导致作物生长期延长。在第二类实验中,土壤压实改善措施显著影响拔节时间、成熟时间、植株高度、每平方米分蘖数、每平方米穗数、每穗粒数、千粒重、生物质产量、产量、收获指数、根系长度、作物生长率、谷物蛋白质含量,下表层土壤强度、容重、空隙度,植株中N、P、K含量,土壤N、P、K含量。同时,对出苗时间、出苗率、每平方米穗数,表层土壤圆锥指数、容重、空隙度没有显著影响。这些参数值在S4组中最大,其次是S2组。除土壤容重外,在S5组中各参数值最小,而对土壤容重来说,则是在S5组中最大,在S4和S2组中达到最小。之所以深耕和厩肥的使用有较好的效果,是由于它们可以改善土壤的结构,进而促进了作物的生长。因此土壤压实对作物生长的负面影响可以通过用这些措施来改善。虽然年份和压实之间的交互影响作用不确定,但是,第二年中的各参数实测值要高于第一年。

论文目录

• 摘要
• ABSTRACT
• CHAPTER 1 INTRODUCTION
• References
• CHAPTER 2 REVIEW OF LITERATURE
• 2.1 Compaction effects
• 2.2. Improvements measure effects
• 2.3 Farming under compaction
• 2.4 Influence of soil water content on soil compaction
• 2.5 Mechanized farm operations and soil compaction
• 2.6 Effects of wheels and tyres on soil compaction
• 2.7 Number of passes
• 2.8 Plant roots and soil compaction
• Reference
• CHAPTER 3 MATERIALS AND METHODS
• 3.1 Effects of soil compaction on soil properties and crop growth
• 3.1.1 Site Description
• 3.1.2 Field experiments
• 3.1.3 Soil
• 3.1.4 Tractors Used
• 3.1.5 Experimental Design
• 3.1.6 Treatments and Experimental layout
• 3.1.7 Effects of soil compaction on soil properties
• 3.2 Effects of improvement measures applied to compacted subsurface soil
• 3.3 Data Collection
• 3.4 Methodology for recording data
• 3.4.1 Soil bulk density
• 3.4.2 Total porosity
• 3.4.3 Penetration measurements
• 3.4.4 Soil compaction comparison among HT,WT and CT
• 3.4.5 Effect of the number of tractor passes on penetration resistance
• 3.4.6 Rut Depth
• 3.4.7 Plowing effect on penetration resistance
• 3.4.8 Shear strength
• 3.5 Effects of soil compaction on crop response
• 3.5.1 Herbicide
• 3.5.2 Days to emergence
• 3.5.3 Emergence per square meter
• 3.5.4 Days to anthesis
• 3.5.5 Days to maturity
• 3.5.6 Plant height（cm）
• 3.5.7 Tillers per square meter
• 3.5.8 Spikes per square meter
• 3.5.9 Grains per spike
• 3.5.10 Thousand grain weight（TGW）（g）
• 3.5.11 Dry matter
• 3.5.12 Biological yield
• 3.5.13 Grain yield
• 3.5.14 Harvest index
• -2.days^-1）'>3.5.15 Crop growth rate（g·m^-2.days^-1）
• 3.5.16 Root length
• 3.6 Effects of soil compaction on crop protein
• 3.6.1 Grain protein
• 3.6.2 NirtogeneoneentrationinPlanst（%）
• 3.6.3 PhosPhoruseoneentrationinPlants（%）
• 3.6.4 PotassiumConcentrationinPlanst（%）
• 3.6.5 Total soil N
• 3.6.6 Available soil P
• 3.6.7 Available soil K
• 3.6.8 Percent values of N,P and K in FYM
• Reference
• CHAPTER 4 EFFECTS OF SOIL COMPACTION ON SOIL PROPERTIES AND CROP GROWTH
• 4.1 Introduction
• 4.2 Effects of compaction on soil properties
• 4.2.1 Relationship between soil water content and penetration resistance
• 4.2.2 Soil compaction comparison among treatments
• 4.2.3 Number of tractor passes impact on penetration resistance
• 4.2.4 Plowing impact on penetration resistance
• 4.2.5. Soil physical properties
• 4.2.6. Rut depth
• 4.2.7 Upper surface soil bulk density
• 4.2.8. Subsurface soil bulk density
• 4.2.9 Upper surface soil porosity
• 4.2.10 Total porosity of subsurface soil
• 4.2.11 Effect of compaction on shear stress
• 4.3 Effects of subsurface suil compaction on crop response
• 4.3.1 Days to emergence
• 4.3.2 Emergence per square meter
• 4.3.3 Days to anthesis
• 4.3.4 Days to maturity
• 4.3.5 Plant height
• 4.3.6 Tillers per square meter
• 4.3.7 Spikes per square meter
• 4.3.8 Grain per spike
• 4.3.9 Thousand grain weight（TGW）
• 4.3.10 Biological Yield
• 4.3.11 Grain yield
• 4.3.12 Harvest Index（HI）
• 4.3.13 Crop growth rate
• 4.3.14 Root length
• 4.4. Effect of subsurface soil compaction on crop nutrients from soil
• 4.4.1 Grain protein
• 4.4.2 Nitrogen concentration in plants
• 4.4.3 Phosphorus concentration in plants
• 4.4.4 Potassium concentration in plants
• 4.4.5 Nitrogen（N）uptake by plants
• 4.4.6 Phosphorous（P）uptake by plants
• 4.4.7 Potassium（K）uptake by plants gram per square meter
• 4.4.8 Total Soil Nitrogen
• 4.4.9 Available Soil Phosphorus
• 4.4.10 Available Soil Potassium
• 4.5 DISCUSSION
• References
• CHAPTER 5 SUBSURFACE SOIL COMPACTION AND IMPROVEMENT STRATIGIES
• 5.1 Introduction
• 5.2 Effects of improvement measures on soil properties
• 5.2.1 Effects of improvement measures on upper surface soil bulk density
• 5.2.2 Effects of improvement measures on subsurface soil bulk density
• 5.2.3 Effects of improvement measures on porosity of upper surface soil
• 5.2.4 Effects of improvement measures on total porosity of subsurface soil
• 5.2.5 Effects of compaction on penetration resistance
• 5.3 Effects of improvement measures on crop
• 5.3.1 Days to emergence
• 5.3.2 Emergence per square meter
• 5.3.3 Days to anthesis
• 5.3.4 Days to maturity
• 5.3.5 Plant height
• 5.3.6 Tillers per square meter
• 5.3.7 Spikes per square meter
• 5.3.8 Grains per spike
• 5.3.9 Thousand grain weight（TGW）
• 5.3.10 Biological yield
• 5.3.11 Grain yield
• 5.3.12 Harvest Index（HI）
• 5.3.13 Crop growth rate
• 5.3.14 Root length
• 5.4 Effects of improvement measures on crop nutrients
• 5.4.1 Grain protein
• 5.4.2 Nitrogen concentration in plants
• 5.4.3 Phosphorous concentration in plants
• 5.4.4 Potassium concentration in plants
• 5.4.5 Nitrogen uptake by plants
• 5.4.6 Phosphorous uptake by plants
• 5.4.7 Potassium uptake by plants
• 5.4.8 Total soil Nitrogen
• 5.4.9 Available soil phosphorous
• 5.4.10 Available soil potash
• 5.5 DISCUSSION
• References
• CHAPTER 6 CONCLUSIONS AND SUGGESTIONS
• 6.1 CONCLUSIONS
• 6.2 ACHIEVEMENTS
• 6.3 PRACTICAL SOLUTIONS TO REDUCE THE RISK OF SOIL COMPACTION
• 6.4 IMPLICATION OF FUTURE RESEARCH
• APPENDICES
• RESEARCH PAPERS
• ACKNOWLEDGEMENTS