【作者】 王群；

【导师】 李潮海；

【作者基本信息】 河南农业大学 ， 作物栽培学与耕作学， 2010， 博士

【摘要】 本文于2007-2009年在不同类型土壤(原状潮土、砂姜黑土和黄褐土)上采用桶栽(盆栽)和大田等种植方式,系统研究了紧实胁迫对不同类型土壤上玉米根系的时空分布和生理功能、根显微结构、呼吸代谢和内源激素含量变化、植株养分吸收与分配、氮肥利用效率、地上部生长发育和产量形成、土壤微生物量和土壤呼吸速率变化规律,以及土壤耕作措施的调控效应,以期为提高玉米产量提供理论和技术依据。1、紧实胁迫下根系的形态和生理功能发生明显改变,高紧实胁迫下显著降低了玉米单株根长度、根干重、根总表面积和根体积,使根直径增粗;紧实胁迫使根系的生理特性也受到明显影响,高紧实度下根总吸收面积和活跃吸收面积、根系活力和根系ATP酶活性下降,单根吸收强度(比吸收表面和比活跃吸收表面)增加,根冠比降低。不同类型土壤对紧实度的反应不同,各指标总趋势表现为潮土>砂姜黑土>黄褐土,对紧实胁迫的响应以砂姜黑土和黄褐土较为敏感,变幅较大,潮土变幅较小。在玉米生育期间各项指标呈单峰曲线变化,吐丝期达到最大。2、紧实胁迫下根系基本组织内形成大量溶生型气腔,气腔数量和气腔面积均显著高于正常紧实土壤;紧实胁迫下根的皮层厚度和中柱直径增加,导管数量和导管直径也有不同程度的增加;根系皮层薄壁细胞在紧实胁迫下径向长度和横位直径均受到明显制约,与正常土壤对照差异达极显著。不同类型土壤上根横切结构的变化总的表现为潮土>砂姜黑土>黄褐土,以砂姜黑土和黄褐土对紧实胁迫的响应较为敏感。紧实胁迫下根系的无氧呼吸代谢功能增强,表现为无氧呼吸关键酶——PDC、LDH、ADH酶活性显著增加,无氧代谢产物乳酸、乙醛和乙醇含量急剧增加,虽然紧实胁迫下无氧呼吸代谢并未像淹水缺氧胁迫下剧烈,但紧实胁迫已表现出明显的缺氧胁迫机制。紧实胁迫下根系的内源激素IAA、GA、ZR含量呈现明显下降趋势,ABA含量显著增加,且紧实胁迫IAA/ABA、GA/AB、ZR/ABA比值低于正常紧实土壤,而IAA/ZR则高于正常紧实土壤;受土壤紧实胁迫的影响,根系SOD和POD酶活性均呈现不同程度的下降,MDA含量上升。3、紧实胁迫下单株氮磷钾累积量和器官中的分配量均表现为:潮土>砂姜黑土>黄褐土,且处理间差异显著;器官中养分分配比例以叶片中的高于茎鞘;各处理后期养分转移率表现为黄褐土>砂姜黑土>潮土。降低土壤紧实度增加了各类土壤上玉米单株和各器官中氮磷钾的累积量,其中黄褐土和砂姜黑土增加幅度较大,潮土增幅较小;随着紧实度的降低,玉米叶片和茎鞘中的氮磷钾转移率呈下降趋势。不同类型土壤氮肥利用效率与植株吸氮量呈相反变化趋势,表现为潮土小于砂姜黑土和黄褐土,潮土比砂姜黑土和黄褐土氮素表观利用效率分别小3.1%和3.6%;降低土壤容重后总吸氮量和氮肥表观利用率和氮肥农学效率均明显提高,其中潮土、砂姜黑土和黄褐土的氮素表观利用率分别提高了4.3%、6.0%和5.4%,氮肥农学效率分别提高了2.59 kg·kg-1、4.28 kg·kg-1和1.87kg·kg-1。4、在玉米生长季节,土壤微生物碳、氮总量、各层次土壤微生物量碳氮及微生物熵(MBC/SOC)和MBN/TN均呈单峰曲线,峰值在吐丝期;紧实胁迫下,不同类型土壤微生物量碳氮变化顺序为潮土>砂姜黑土>黄褐土;降低土壤紧实度,各处理微生物量碳、氮值升高,以黄褐土和砂姜黑土增幅较大,潮土增幅较小,低紧实度对20-40cm土层的微生物量碳、氮影响效应比0-20cm更为显著。不同类型土壤MBC/SOC变化顺序为黄褐土略高于潮土和砂姜黑土,而MBN/TN变化趋势与之相反;降低土壤紧实度,提高了各处理的MBC/SOC和MBN/TN值, MBC/SOC以黄褐土和潮土提高幅度较大,砂姜黑土较小,MBN/TN则以黄褐土和砂姜黑土提高幅度大于潮土;微生物C/N比则变化顺序为黄褐土>砂姜黑土>潮土,降低紧实度使微生物C/N比值下降。微生物量碳、氮与有机碳、全N、速效N呈显著正相关,微生物熵与有机碳和微生物量碳也呈显著或极显著相关性。不同类型土壤呼吸速率和日变化均呈单峰曲线,裸土上土体呼吸和种植玉米的土壤呼吸峰值分别出现在吐丝后25天和吐丝期,不同类型土壤呼吸速率变化依次是潮土>砂姜黑土>黄褐土;降低土壤紧实度增加了各处理土壤呼吸速率,不同类型土壤以砂姜黑土增幅最为明显;影响土壤呼吸速率因素从大到小依次为根系生物量、地上生物量、总生物量、叶面积指数、微生物碳、氮、土壤温度、土壤水分。5、玉米生育期间,3种类型原状土壤上玉米叶面积指数、可溶性糖含量呈单峰曲线变化趋势;SPAD值从吐丝后14天开始趋于下降,干物质积累呈上升趋势;叶面积指数、株高、茎粗、叶绿素值、干物质量、可溶性糖含量、穗粒数和产量均表现为潮土>砂礓黑土>黄褐土,且株高、茎粗、穗粒数和产量在各处理间差异达显著水平。降低土壤紧实度,3种类型土壤上各项指标均呈现不同程度的增加,尤其以砂礓黑土和黄褐土较为明显,降低紧实度前后各类土壤的株高、茎粗、产量间差异均达显著水平。紧实度显著影响玉米穗粒数的变化,但对百粒重影响较小。降低土壤紧实度虽然能改善玉米的根系和地上部的生长状况,缩小各类土壤间的差异,但并不能改变三类土壤上各指标的变化顺序,仍然为T潮土>T砂姜黑土>T黄褐土。通过大田土壤深耕或者深耕起垄等耕作措施,有效降低了土壤容重和紧实性,大幅度提高了土壤孔隙度,尤其对10-20cm和20-30cm土层效果更为显著,两土层平均容重降低10.41%和13.97%,孔隙度增加17.91%和30.51%;降低紧实度使大田玉米穗长平均增加幅度为4.76%-8.63%、穗粒数和产量增加幅度分别6.89%-12.70%和10.35%-16.71%。更多还原

【Abstract】 Improving grain yield of maize and soil productivity is now one of the key subjects.Soil compaction is a main constraint to root and shoot growth, it is the main physical stress that limits crop growth and yield.The studies on the effect of the soil compaction stress on the maize Eco-physiology and regulate measures were carried out at three locations, Henan Agricultural University Experomental Station with the methods of pot and barrel research combined with field research on three soil types during 2007-2009,repectively.Effects were studied of soil compaction stress on the growth and distribution of root, root microstructure, root respiratory metabolism, root endogenous hormones, nutrient absorbing and distribution, soil microbial biomass carbon and nitrogen , soil respiration and corn growth and yield. The results were as follows:;1、A barrel expriment were conducted to research root morphology and physiological characteristics in three soil types(fluvo-aquic soil, lime concretion black soil and yellow cinnamon soil) under soil compaction stress.The results showed that root length, root dry weight ,individual root, total root surface area,root volume were decreased significantly under soil compaction stress in different soil types, while that of root diameter exhibited the opposite. In addition, root total absorbing area, root activitily absorbing area, root activities , root ATPase activity and root/shoot ratio declined prominently. Ratio of absorbing area and ratio of activitily absorbing area to root weight were increased distinctly. The order of all parameters was fluvo-aquic soil > lime concretion black soil > yellow cinnamon soil, but three soil types varied different trend responding to soil compaction stress, Among them lime concretion black soil and yellow cinnamon soil were influenced largely and sensitivily, while fluvo-aquic soil was influenced slightly by soil compaction stress. During the growth of maize, some parameters were single peak curves, The highest values appeared at the silking stage.2、In the pot experiments stated ablove,studies were carried out to evaluate the effects of soil compaction stress on root morphology, root respiratory metabolism, root endogenous hormones and root protective enzyme activity under three soil types. The results showed that there were much more aerenchyma formation under soil compaction stress. Aerenchyma number and aerenchyma area on the root transection were increased significantly under high soil compaction. Length of cortex and diameter of plerome were also enhanced largely, and number and diameter of vessel were increased to some cxtent. Radial and transverse length of cortical cells discreased under soil compaction stress.The diversity of them were extremely significant between high soil compaction and normal soil compaction. There were different orders among three soil types. Lime concretion black soil and yellow cinnamon soil were influenced largely and sensitivily among them.The activities of pyruvate decarboxylase(PDC), lactate dehydrogenase(LDH) and alcohol dehydrogenase(ADH) increased significantly under soil compaction stress.The contents of lactat, acetaldehyde and alcoho also were increased evidently under high soil compaction.but increment of these indexes was lesser than that of these under water-logging treatment.The contents of indoleacetic acid (IAA),gibberellins (GA) and zeatin riboside (ZR) in root decreased under high soil compaction,while abscisic acid content in root increased. The value of IAA/ABA,GA/ABA,ZR/ABA were lower under high soil compaction than normal compaction.while the value of IAA/ZR was higher under high soil compaction. Under soil high compaction activities of superoxide dismutase (SOD) and peroxidase (POD) decreaesed to some extent, but content of (MDA)was enhanced significantly.3、Under high soil compaction the order of nutrient accumulation was N>K>P in different soil types, and the order of total accumulation of N, P, K in per corn was fluvo-aquic soil>lime concretion black soil>yellow cinnamon soil. Statistical analysis indicated that there were significant difference among these soil types. The order of nitrogen, phosphorous and potassium consumption in leaves and culm-sheath agreed with that in plant, and the proportion of distribution in leaves was a few higher than that in the culm-sheath. Total accumulation of N, P, K in per corn and distribution of N,P,K in leaf, culm-sheath and grain were enhanced highly with the decreasing of soil compaction.Among three soil tyes the extent of increasing in lime concretion black soil and yellow cinnamon soil were higher than that in fluvo-aquic soil. Besides the transferring rate of N,P,K in leaves and culm-sheath were increased a littler under high soil compaction.In three soil types the order of nitrogen use efficiency was fluvo-aquic soil<lime concretion black soil<yellow cinnamon soil under high soil compaction. nitrogen use efficiency in fluvo-aquic soil decreased by 3.1% and 3.6% than others.Decreasing soil compaction, nitrogen accumulation, nitrogen agronomic efficiency and nitrogen use fertilizer efficiency were improved lightly. They increased respectively by 4.3%,6.0% and 5.4% in fluvo-aquic soil,lime concretion black soil and yellow cinnamon soil. Nitrogen agronomic efficiency was increasing respectively by 2.59 kg·kg-1、4.28 kg·kg-1and 1.87kg·kg-1 in three soil types.4、During the growth of maize, Soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), microbial carbon to organic carbon(Cmic-to-Corg) and microbial nitrogen to total nitrogen ratio(MBN/TN) were a single curve,and the high value of them were at the silking stage.The order of three soil types was fluvo-aquic soil>lime concretion black soil>yellow cinnamon soil under soil high compaction. With soil compaction decreasing, SMBC and SMBN were increasing. These were enhanced highly in lime concretion black soil and yellow cinnamon soil and increased less in fluvo-aquic soil.The effect of soil high compaction on SMBN and SMBC were more evident in the 20-40 cm than in the 0-20 cm.The value of MBC/SOC was higher in yellow cinnamon soil than in fluvo-aquic soil and lime concretion black soil,while the value of MBN/TN exhibited opposite. The lower the soil compaction, the more significant the increasing the value of MBC/SOC and MBN/TN.The increase of MBC/SOC was higher in yellow cinnamon soil and fluvo-aquic soil,while the increase of MBN/TN was less in lime concretion black soil.The order of value of soil microbial biomass carbon to soil microbial biomass nitrogen (SMBC/SMBN) was yellow cinnamon soil > lime concretion black soil> fluvo-aquic soil.The value of SMBC/SMBN decreased with the soil compaction decreasing. SMBC and SMBN were positive correlation with soil organic carbon,total nitrogen and available nitrogen. MBC/SOC was extreme correlation with SOC and SMBC.The soil respiration and dinrual changes of its were single curve in different soil types under soil high compaction.The highest values of soil respiration and rhizospheric respiration were at the silking stages and 25th day after silking respectively. The order of respiration changes was fluvo-aquic soil>lime concretion black soil>yellow cinnamon soil.These were some factors of root biomass,organism biomass,total biomass, leaf area index,SMBC,SMBN,soil temperature and soil moisture on soil respiration in turn.5、During the growth of maize, Leaf area index(LAI) and content of soluble sugar were single curves.The value of SPAD decreased from 14th day after silking.The order of changes of LAI,height and diameter of stem,dry matter,content of soluble sugar,value of SPAD and yield was fluvo-aquic soil>lime concretion black soil>yellow cinnamon soil.these diversity were significantly.These parameters increased evidently with soil compaction decreaesing.but 100 kernel weight was affected hardly.With soil compaction decreasing,the difference was reduced significantly.The order of different soil types was not changed.this was also T fluvo-aquic soil>T lime concretion black soil>T yellow cinnamon soil.By deep tillage or deep tillage added ridging,soil compaction and bulk density decreased ,and soil porosity was enhanced extremely significantly.The decreasing of soil bulk density was by 10.41% and 13.97% in the 0-20cm and 20-40cm depth. The increasing of soil porosity was by 17.91% and 30.51%in this two soil layers.The kernel per plant and yield were increasing by 6.8-12.7% and 10.35%-16.71%with soil conmoaction decreasing.更多还原