【作者】 王红丽；

【导师】 宋尚有；

【作者基本信息】 甘肃农业大学 ， 作物栽培学与耕作学， 2012， 博士

【摘要】 玉米（Zea mays L.）是我国仅次于水稻、小麦的第三大粮食作物。建国后种植面积和单产逐年增加。但随社会经济发展和城镇化推进，可持续耕地面积逐渐减少，玉米种植面积的增加不大，其产量的增加只能靠提高单产来实现。近年来，全膜双垄沟播玉米种植技术在西北干旱半干旱地区大面积推广，可显著提高玉米产量，但其增产机制仍需系统研究分析。本文以春玉米为试验材料，在位于西北黄土高原丘陵沟壑区半干旱区的定西市安定区于2009-2010年进行大田定位试验，设全膜双垄沟播、全沙覆盖平作和裸地平作三个处理，测定玉米全生育期的土壤耕层温度、0-200cm土层土壤水分、玉米生长发育指标、干物质累积和产量构成因子等，计算玉米阶段性耗水、水分利用效率，探讨全膜双垄沟播的增产机制及其对土壤水分平衡的影响，得到如下主要结果：1．全膜双垄沟播（whole field surface plastic mulching and double ridge-furrow planting，PMF）能提高玉米苗期-抽雄期0-25cm土壤平均温度3℃左右，利于玉米早生快发；其地温与气温线性相关，但线性拟合曲线的斜率小于SM和CK，尤其是10cm以下土层地温对气温波动的响应灵敏度低于SM和CK，地温相对稳定，为玉米生长提供较好的温度条件；SM增温和稳定地温的作用均弱于PMF；2．三种种植方式在地温最低点，温度梯度为正值，土壤热量从土壤深层传向地表，在地温最高点，温度梯度为负值，土壤热量从土壤表层传向深层；拔节期前，无论在地温最低或最高点，PMF温度梯度最大，SM居中，CK最小，PMF土壤导热性强于其余2个处理；拔节后-成熟期，地温最低点温度梯度PMF﹥SM﹥CK，地温最高点PMF﹤SM﹤CK，可见玉米生育中后期地温较高时段，PMF土壤导热性弱于SM和CK，而地温较低阶段则相反，表明PMF能响应土壤热状况的改变从而调节土壤热量传导性能，维持土壤温度的稳定；在PMF和SM增温和稳定地温作用下，玉米生育期提前，总生育期缩短，但生殖生长阶段延长，有利于玉米籽粒灌浆。3．PMF明显改善玉米拔节前0-200cm土壤水分条件，并减少此阶段地表蒸发为主的水分消耗，提高土壤水分保蓄的能力，在玉米需水较少阶段储蓄更多水分供需水盛期使用。拔节期前，2009年PMF0-60cm土壤贮水量较SM和CK平均增加9.5mm和18.2mm，60-120cm平均增加13.7mm和9.6mm，2010年0-60cm土壤贮水量较SM和CK平均增加24.7mm和6.9mm，60-120cm平均增加8.6mm和14.2mm；随玉米生育进程的推进，3种处理的耗水量依次为：PMF﹥SM﹥CK，而土壤贮水量表现为CK﹥SM﹥PMF；玉米拔节后，PMF耗水加快，其中灌浆期最为显著，其次是拔节-抽雄期。灌浆期，2009年PMF耗水量较SM和CK提高72.0%和190.8%，2010年提高84.5%和237.7%，拔节-抽雄期，2009年PMF耗水量较SM和CK提高8.2%和23.9%，2010年提高8.2%和37.8%，为玉米生殖生长提供较好水分条件；玉米耗水高峰的出现与当年降雨充沛时段基本吻合；SM在一定程度减少地表蒸发，促进生殖生长阶段耗水，但效果显著弱于PMF；4．PMF因前期温度、水分条件好，耗水量增加，促进了玉米叶的生长和干物质累积。PMF处理的LAI在玉米整个生育期均大于SM和CK，并在整个生殖生长阶段保持相对较高的LAI，因此，PMF干物质累积量最大，相对旺盛的营养生长为生殖生长和产量形成提供支撑；再者PMF和SM生殖生长阶段延长，玉米生育后期耗水显著增多，在整个生殖生长阶段提高并维持较高地上干物质水分利用效率（WUEb），促进了光热水资源的利用，因而使玉米穗长、穗粒数、穗粒重、百粒重显著提高，产量较CK增加310.0%-356.2%，HI增加95.3%-169.6%；SM增产效果小于PMF，产量较CK增加224.3%-256.1%，HI增加76.1%-156.0%；5．PMF和SM地上干物质水分利用效率（WUEb）和籽粒水分利用效率（WUEg）均显著大于CK（P＜0.05）。与CK相比，PMF和SM不仅能提高WUEb，而且能在玉米生殖生长阶段维持长时间高WUEb。抽雄后PMF处理的玉米WUEb下降幅度在4.8-6.1%之间，SM在5.8-7.9%之间，而CK在9.0-25.6%之间。玉米生殖生长阶段持续较高的WUEb，促进玉米对水分的高效利用，使PMF的WUEg较CK提高265.6%-315.5%；SM全生育期WUEg同样显著高于CK，较CK提高204.9%-249.3%；6．PMF在获得持续高产的同时，加快了土壤水分的循环和消耗，以较快速度和较大程度耗散了土壤蓄存水分。所以，在相同降雨条件下，PMF处理0-200cm土壤水分降雨入渗补给深度最大，SM次之，CK最小；在这种吸水腾空库容，入渗加快，土壤水分条件改善，再次促进耗水的驱动下，PMF耗水量和耗水深度随种植年限的增加而增加，本试验两年种植期间耗水深度从20-120cm向120-200cm推移，连续种植两年后，3种处理40-120cm土壤含水量下降至9%以下，其中PMF下降最快，降至7.9%，土壤含水量接近萎蔫系数7.2%，玉米只能靠当年降水生长，但本试验区常有降水供需错位的气象特征，如种植年限继续增加，土壤水分持续消耗加上补给不足，极有可能导致土壤干层形成，土壤水分平衡被打破和土壤水分生态环境被恶化的潜在风险增加；可见，PMF首先是提高玉米苗期-抽雄期0-25cm土壤平均温度并增大拔节期前土壤温度梯度，显著改善玉米拔节期0-200cm土壤水分条件，促进前期营养生长；在玉米生育中后期，PMF因前期累积的较大营养体促进了生殖生长阶段耗水，尤其是灌浆期，促进玉米生育后期光合产物向籽粒转移，促进籽粒灌浆，在玉米对光热水资源更好利用的基础上，玉米穗部性状得到最大程度的改善，穗长、穗粒数、粒重显著增加，产量和水分利用效率（包括WUEb和WUEg）显著提高，但代价却是土壤蓄存水分的大量消耗。两年种植期间耗水深度从20-120cm向120-200cm推移，连续种植两年后，0-200cm土壤耗水量达163.6mm，40-120cm土壤含水量下降至7.9%，接近萎蔫系数7.2%，玉米只能靠当年降水生长，土壤水分平衡被打破和土壤水分生态环境被恶化的潜在风险增加。可见，PMF对作物和土壤环境的一系列效应均在温度梯度驱动下热量和水分的上下迁移过程中完成，而且这一过程对玉米生产有利，对土壤水分环境不利。更多还原

【Abstract】 Corn (Zea mays L.) is the third mainly crop (inferior to wheat and rice) in China. its plantingarea is increasing yearly from1949to nowadays. However, the cropland area is decreasing withthe development of economy and town expanding, resulted in the restricted area of corn, and theproductivity of corn is determined by unit yield solely. Recently, whole field surface plasticmulching and double ridge-furrow planting (PMF), a new technology increased corn yieldsignificantly, is applied widely in arid and semi-arid northwestern China. However, there has nosystemic research on the mechanism of improvement of PMF. To explore these, field experimentwere conducted in dingxi county of Gansu province during2009-2010, where locates at hilly andsemiarid northwest Loess plateau. Three treatments involved in the field experiment,1) wholefield surface plastic mulching and double ridge-furrow planting (PMF),2) whole field surfacesand mulching and flat planting (SM), and3) flat planting without mulching (CK), designedrandomly and replicated three times. Soil temperature, soil water storage, crop growth index, drymass, water consumption in different growth stages, water use efficiency, yield and yieldcomponent of corn were determined and analyzed. The main results are as follows:1. PMF increased soil average temperature about3℃in0-25cm soil profile duringSeeding-Heading stage of corn, as compare with CK, improved corn development in early growthperiod. Soil temperature of PMF was linear correlation with air temperature, but responsiblesensitivity was lower than SM and CK, especially in10-25cm soil profile. Therefore, PMF couldsustain relative stable soil temperature, benefit to corn development. SM also could improve andsustain relative stable soil temperature, but the impact was not significant as PMF.2. At the minimum soil temperature point, soil temperature gradient (Gra) of three treatmentswas positive, the deeper soil heat transported to surface. However, the Gra was opposed at themaximum soil temperature point. Before corn jointing, whether at the minimum or maximum soiltemperature point, Gra followed the sequence as PMF﹥SM﹥CK, soil thermal conductivity ofPMF was stronger than SM and CK. From corn jointing to harvest, Gra followed the sequence asPMF﹥SM﹥CK at the minimum soil temperature point, and followed the sequence as PMF＜SM＜CK at the maximum soil temperature point, then, it suggested that soil thermal conductivity of PMF was stronger at lower soil temperature condition, weaker at higher soil temperature stage,plastic mulching adjust the characteristics of soil thermal conductivity, keep the relative stable soiltemperature, therefore, PMF improve corn growth, advance corn growth stage, shorten the wholegrowing stage, especially, extend the reproductive growth period, its benefit to corn filling.3. PMF could improve soil water storage in0-200cm profile and reduce evaporationsignificantly before corn jointing, enhance the soil water capacity, the more soil water sustainedfor later corn development. As compared with SM and CK, before corn jointing, PMF increasedsoil water storage by9.5mm and18.2mm in0-60cm soil profile, by13.7mm and9.6mm in60-120cm soil layer in2009, and by24.7mm and6.9mm in0-60cm soil layer, by8.6mm and14.2mm in60-120cm soil layer in2010, respectively. With the corn growth, there was a significant differencein water consumption between three treatments, which followed the sequence as PMF>SM>CK.Conversely, the change of soil water storage followed as CK>SM> PMF.After corn jointing, cornwater consumption accelerated, the most significantly stage was filling, then was the stage fromjointing to heading. During corn filling stage, as compared with SM and CK, water consumptionof PMF increased by72.0%and190.8%in2009, by84.5%and237.7%respectively in2010,during corn jointing-heading stage, water consumption of PMF increased by8.2%and23.9%in2009, by8.2%and37.8%respectively in2010. Thus, PMF could sustain a relatively better watercondition for corn reproductive growth. The water consumption peak was adaptive to thedynamics of precipitation. SM also could reduce evaporation and promote water use inreproductive growth period, but the effect was not significant as PMF.4. PMF increased soil temperature, soil water storage during corn growth early stage,increasd corn water consumption, therefore, improved leaf growth and biomass accumulation ofcorn. Leaf area index (LAI) of PMF was higher than SM and CK through whole corn growingstage and keep higher LAI in whole reproductive growth period, therefore, dry matteraccumulation of PMF was highest among three treatments, better vegetative growth supportreproductive growth and yielding. PMF and SM elongated reproductive growth period andaccelerate water consumption during corn reproductive stage, keep higher water use efficiencybiomass(WUEb) in whole reproductive growth period, benefit to the using of light, heat and water.Therefore, spike length, grain number per spike, grain weight per spike,100-grain weigh of cornwere increased significantly. For example, corn yield, harvest index (HI) of PMF increased by310.0%-356.2%and95.3%-169.6%respectively, as compared with CK. Likely, SM also increased corn yield and HI by224.3%-256.1%and76.1%-156.0%, respectively.5. WUEband WUEgof PMF were higher than CK significant, as well as SM treatment. AsCompared with CK, PMF and SM not only improved WUEb, but also kept higher WUEbthroughcorn reproductive growth period. After corn heading, WUEbof PMF decreased by4.8-6.1%,WUEbof SM decreased by5.8-7.9%, and WUEbof CK decreased by9.0-25.6%, resulted in theincrement of WUEgby265.6%-315.5%in PMF treatment, by204.9%-249.3%in SM treatment,respectively, as compared with CK.6. PMF increased corn yield continuously, but speeding up the soil water cycle andconsumption, as well as increased the water loss in deeper soil profile. Thus, the restored depth ofsoil water in0-200cm soil profile was deepest in PMF treatment under the same annualprecipitation, and then was SM, CK was shallowest. Under PMF treatment, the quicker soil waterloss promoted the speed of soil water restoration, further, the quicker soil water restoration drovethe crop water consumption, so the quantity and depth of soil water consumption in PMFtreatment increased with the increases of corn planting years. For example, from2009to2010, thedepth of soil water loss increased from20-120cm profile to120-200cm profile. After2years corncontinuous cropping, soil water content in40-120cm profile was less than9%in all threetreatments, especially, the soil water content of PMF treatment was7.9%, closed to the wiltingcoefficient (7.2%), corn development only depending on rainfall in growth season. The dynamicof precipitation was not coincide with corn water need in the experimental area, the continuouscorn cropping with PMF probably caused soil dry layer in semiarid area. Therefore, PMF couldimprove corn yield significantly, but continuous cropping may result in the significant reductionof soil water storage, and was disadvantage to the sustainable the balance of soil water storage.We can conclud that PMF firstly increased soil average temperature in0-25cm soil profileduring Seeding-Heading stage, increased Gra and0-200cm soil water storage before jointing stageof corn, improve corn development in early growth period. Secondly, PMF increased waterconsumption during corn reproductive growth stage, especially filling stage, promoted thetransferring of energy to grain, improved filling, benefit to the using of light, heat and water, thus,spike properties of corn improved significantly, spike length, grain number per spike, grain weightper spike and then yield, WUE(WUEband WUEg) of corn increased significantly. But, the costwas the huge consumption of soil water. For example, from2009to2010, the depth of soil waterloss increased from20-120cm profile to120-200cm profile. After2years corn continuous cropping, soil water consumption in0-200cm was up to163.6mm, soil water content in40-120cmprofile was7.9%, closed to the wilting coefficient (7.2%), corn development only depending onrainfall in growth season, the potential risk increased that soil water balance was broken and soilwater ecosystem was deteriorated. Therefore, effect of PMF on crop and soil was drove by Gra,taken by transferring of soil heat and water, was advantage to corn but disadvantage to soil waterecosystem.更多还原