【作者】 刘浩；

【导师】 段爱旺；

【作者基本信息】 中国农业科学院 ， 农业水土工程， 2010， 博士

【摘要】 温室能充分调节利用光、热、水、土资源,为作物的生长发育提供适宜的环境。随着社会经济的快速发展和生活水平的日益改善,人们更加重视蔬菜产品品质的提高和无公害生产。在水资源日益紧缺的大背景下,以滴灌为主的节水灌溉技术被越来越多的应用于温室蔬菜的生产中,并突显出其优越性和重要性。基于目前的社会经济形势,研究滴灌条件下温室蔬菜的需水特性及优质高效灌溉指标,可以促进日光温室蔬菜节水灌溉的发展,提高水分利用效率,实现日光温室蔬菜的优质高产、以水调质的功效,对日光温室水肥资源高效利用及生产效益的提高具有重要意义。本项研究以种植区域十分广泛、种植面积非常大的番茄为主要研究对象。试验于2008年和2009年在中国农业科学院农田灌溉研究所作物需水量试验场内的日光温室中进行,采用常见的宽窄行方式种植。根据番茄的生长发育特性,将番茄的整个生育期划分为苗期、开花坐果期和成熟采摘期3个阶段,在苗期设计3个土壤水分控制下限(占田间持水量的百分比)处理,在开花坐果期和成熟采摘期都设置4个土壤水分控制下限处理,另外设置一个全生育期都充分供水的处理作为对照,共计10个试验处理。试验采用随机布设,重复3次。通过两年较为系统的田间试验和实验室分析,对不同土壤水分状况下温室番茄植株生长发育状况、生理生态特性、棵间土壤蒸发和植株蒸腾规律、最终产量和产品品质及水分利用效率进行了系统的观察研究,取得的主要研究结果如下:(1)任何生育阶段发生水分亏缺均会降低番茄叶片光合速率及气孔开度,进而影响干物质的累积和运转,但不同时期水分亏缺的影响形式及程度有所不同。苗期水分亏缺会抑制番茄植株的正常生长,但水分过高会使植株营养生长过大,不利于光合产物向果实的运移;开花坐果期水分亏缺不仅抑制了番茄植株的生长发育,而且会降低干物质的累积速率,并最终影响到果实产量;成熟采摘期水分亏缺会加速番茄植株的衰老,降低植株干物质总量,对番茄果实产量的影响最为明显。试验表明,只有在适宜的阶段合理的控制土壤水分下限,才能既不影响番茄植株正常生长发育及生理需水,又能有效地抑制番茄的冗余生长,使光合产物向有利产量形成的方向运转,为产量形成提供良好的基础。(2)番茄苗期适度水分亏缺(土壤水分保持在田间持水量的50%~55%)可提高坐果率,降低畸形果比率,但果实总体偏小,果实成熟主要集中到采摘后期;开花坐果期过度水分亏缺(土壤水分降到田间持水量的65%以下)虽可促进果实成熟,但降低了成果数,且易形成小果和畸形果;成熟采摘期水分过高(田间持水量的80%以上)或过低(田间持水量的65%以下)均会降低番茄产量,水分亏缺(田间持水量的65%以下)使成果数降低、畸形果比率增加。(3)滴灌条件下,温室番茄的耗水量与土壤水分状况(处理)有着密切的关系。不论是总耗水量还是阶段耗水量,均随着土壤水分的降低而减小。番茄产量与全生育期灌水量及耗水量之间均呈现良好的二次函数关系,相关系数均达到0.90以上。温室番茄的经济耗水量在311.83~348.18mm之间。(4)在番茄整个采摘过程中,同一水分处理不同时间采摘的果实,品质具有较大差异。因此,某一次采摘果实的品质测定值,均无法很好地代表整个采摘期的品质性状。这一现象在所有水分处理中都存在。因此,取若干次采摘果实品质测定值的平均值,可以在一定程度上消除采摘时间不同所产生的差异。不同生育阶段土壤水分调控对番茄果实储运品质(硬度)和营养品质(糖酸比、VC含量、可溶性蛋白含量、硝酸盐含量等)的影响程度不同,其中苗期影响较小,开花坐果期和成熟采摘期影响较大。总体上看,果实硬度和VC含量随水分胁迫程度的增加而提高,与耗水量呈线性负相关关系;硝酸盐含量与耗水量呈下凸型二次抛物线关系,糖酸比与耗水量呈上凸型二次抛物线关系,而可溶性蛋白质含量对水分调控的敏感性较小。水分调控可在一定程度上改善果实的某些品质特性。(5)番茄棵间土壤蒸发和植株蒸腾速率受气象条件、土壤水分状况及作物自身生长状况等因素的影响。棵间土壤蒸发与总辐射、气温、饱和水汽压差等气象因子呈指数正相关关系,而植株日茎流量与日总辐射呈线性正相关,与空气饱和水汽压差呈对数正相关关系。相对土壤蒸发强度与番茄叶面积指数呈指数负相关关系,而茎流速率与叶面积指数呈线性正相关关系,二者呈现明显的此消彼长变化。研究结果表明,番茄植株茎流速率经标准化处理后可以很好地表示植株的蒸腾速率。以Penman-Monteith方程为基础,针对温室特定的小气候环境,对番茄冠层整体气孔阻力、空气动力学阻力等参数进行了修正,建立了以气象数据、叶面积指数和冠层高度为主要参数的温室番茄蒸腾量估算模型。分别采用2009年5月2日~13日(处于开花坐果期内)和2009年6月9日~20日(处于成熟采摘期内)两个时段内的茎流速率与茎流量实测值对建立的蒸腾量估算模型进行验证,模拟结果的平均相对误差分别为8.48%和9.20%,表明所建模型可以较好地的计算温室番茄的蒸腾量。通过对温室番茄需水规律及其影响因素的分析,首次提出了基于常规气象数据的温室番茄需水量估算模型,分别采用2009年5月2日~13日(处于开花坐果期内)和2009年6月9日~20日(处于成熟采摘期内)两个时段的实测蒸腾量和实测棵间土壤蒸发量对模型进行验证,模型模拟值的平均相对误差小于10%。在建立的需水量估算模型基础上,引入土壤水分修正系数K(θ),建立了适用于水分胁迫条件下估算温室番茄蒸发蒸腾量的模型。(6)以产量、水分利用效率、单果重、果实硬度、糖酸比和VC含量为主要评价指标,采用主成份分析法,确定了能够实现温室番茄优质、高产、高效三者相统一的土壤水分适宜控制下限指标,即苗期为田间持水量的60%~65%,开花坐果期和成熟采摘期均为田间持水量的70%-75%。更多还原

【Abstract】 Greenhouse technology can contribute to utilize the resources such as light, heat, water and soil in various ways and provide with an optimum environmental medium for crop growth. With the rapid economic development and the improvement of people’s living conditions, people pay more attention to the vegetables quality and non-polluted production. With increasing shortage of water resources, water-saving irrigation technologies mainly in drip irrigation were used in greenhouse vegetable production more and more, and showed an importance and superiority. Base on the current economic situation, water requirement and optimal irrigation index for effective water use and high-quality of tomato in Greenhouse were studied in this paper, which can improve the development of water-saving irrigation and water use efficiency on vegetables in greenhouse and achieve the vegetable products with high-yield and high-quality by water. At the same time, these studies will play an important role in improving high efficient utilization of water and fertilizer and production profit.Tomato, as a vegetable crop, being cultivated in a wide range of region and greater acreage, was regarded as the main research object in this study. The experiment was carried out in a greenhouse in 2008 and 2009 at the water requirement experimental station of Farmland Irrigation Research Institute. Tomatoes were transplanted in wide-narrow row plantation method. According to the growth characteristics of tomato, it was divided into three growing stages, such as vegetative growth stage, flowering and fruit development stage and fruit maturation stage. On the same basis of irrigation endpoint of 90% (taking up percentage of field water capacity), there were three different irrigation water levels (irrigation start point was 50%, 60% and 70%, respectively) at the vegetative growth stage, and four different irrigation water levels (irrigation start point was 50%, 60%, 70% and 80%, respectively) at the flowering and fruit development stage and the fruit maturation stage, respectively. In additiona, an adequate water treatment (irrigation start point was 80% for the whole growing season) was designed as a control. The experiment was laid out in a randomize block design consisting of ten treatments and three replications.Plant growth situation, physioecological characteristics, soil evaporation, plant transpiration, final yield, fruit quality and water use efficiency were investigated with field laboratory experimental data got in two years. The main results were as following:(1) Water deficit at any growth stage decreased photosynthetic rate and stomatal aperture of tomato leaves, furthermore, affected the accumulation and transportation of dry matters, but influencing pattern and degree of water stress were not same at the different growth stages. Water stress inhibited tomato growth and development at the vegetative growth stage, but too enough water led to plant spindling and over growth and affected photosynthate transportation to the fruit. Water stress at the flowering and fruit development stage not only inhibited tomato growth, but also reduced dry matter accumulation, and affected the yield formation. Water deficit at the fruit maturation stage accelerated tomato plants aging, decreased the ultimate amount of dry matters, and affeted yield formation obviously. Therefore, moderate soil moisture can not influence tomato normal growth and physiological water requirement, can inhibit plant excessive growth of tomato and has an advantage of transporting photosynthate to fruit and providing a good base for yield formation.(2) Water deficit (50%～55% of field capacity) occurred at the vegetative growing stage increased fruit numbers and decreased the percentage of malformed fruit, but reduced fruit size generally. Fruit maturation also were delayed and concentrated mainly in the later picking period. During flowering and fruit development stage, severe water deficit (less than 65% of field capacity) promoted tomato fruit maturation, but reduced fruit numbers and increased the risk of forming small fruit and malformed fruit. At the fruit maturation stage, too high (more than 80% of field capacity) or too low (less than 65% of filed capacity) soil moisture both reduced tomato yield, but had few effects on fruit maturation. Too low soil moisture also decreased fruit numbers and increased the percentage of malformed fruit.(3) There was a close relationship between tomato water consumption and soil moisture (water treatment) in greenhouse under drip irrigation. Water consumption was decreased with soil moisture whether in the whole growth season or at any stage. A quadratic function relation with correlation coefficient above 0.90 was showed between tomato yield and water consumption or amount of irrigation in the whole growth season. Economic water consumption ranged from 311.83mm to 348.18mm for the greenhouse grown tomato.(4) There was a difference of fruit quality among the different picking time for the same water treatment in the whole picking process. Quality traits in the whole picking stage would be not represented by one fruit quality value that existing in each treatment. Therefore, takeing the average value of the fruit quality measurement in several times can eliminate differences in the different picking time to a certain extent.The effects of soil moisture at different growth stages on fruit storage-transportation quality (firmness) and nutrition quality (such as sugar-acid ratio, vitamin C content, soluble protein content, nitrate content, etc.) varied, which was little at the vegetative growing stage and large both at the flowering and fruit development stage and fruit maturation stage. Overall, fruit firmness and VC content increased with the degree of water deficit imposed, and a negative linear relationship was observed between these two indexes and water consumption. There was a lower convex second-degree parabola relation between nitrate content and water consumption, but a upper convex second-degree parabola relation between sugar-acid ratio and water consumption. However, the effect of soil moisture on soluble protein content was little in this study. Therefore, water regulation can improve some fruit quality in a certain extent.(5) Soil evaporation and plant transpiration were affected by meteorological condition, soil water moisture and tomato growth status. It was showed that a positive exponential correlation existed between soil evaporation and meteorological factors such as solar radiation, air temperature and vapor pressure difference. Daily sap flow rate had a positive linear correlation with daily solar radiation, and a logarithm relationship with vapor pressure difference. Soil evaporation was negatively exponential correlated with leaf area index, sap flow rate was positive linear correlated with leaf area index, and the obvious interweave changes was showed between soil evaporation and plant transpiration. The study also showed standardized sap flow rate can express the plant transpiration of tomato well.Based on Penman-Monteith equation and the existing research results, the parameters such as canopy stomatal resistance of tomato and aerodynamic resistance were modified in connection with a microclimate environment in greenhouse, and the estimation model of transpiration for greenhouse grown tomato was established by considering the meteorological data, leaf area index and canopy height as main parameters. The model was verified by measurement values of sap flow rate from May 2 to 13 in 2009 (at the flowering and fruit development stage) and from June 9 to 20 in 2009 (at the fruit maturation stage), respectively. The result showed that average relative error for the model simulation was 8.48% and 9.20% at two stages, respectively. Therefore, plant transpiration can be estimated using the model.With the analysis of water requirement and its influence factors for greenhouse grown tomato, the estimation model for water requirement was established for the first time based on the meteorological data. The model was verified by measurement values of transpiration and soil evaporation from May 2 to 13 in 2009 (at the flowering and fruit development stage) and from June 9 to 20 in 2009 (at the fruit maturation stage), respectively. The result showed that average relative error of the model was less than 10%. Based on the model for estimating water requirement, the evapotranspiration model was established by introducing soil moisture correction coefficient K(θ) when water deficit occurred.(6) Taking yield, water use efficiency, single fruit weight, fruit firmness, sugar-acid ratio, VC content as the main evaluation indicator and using the principal component analysis method, the lower limit index of soil water was determined with achieving high yield, high fruit quality and efficiency for greenhouse grown tomato. The lower limit index value of soil moisture was 60%-65%, 70%-75% and 70%-75% of field capacity at the three growth stages of tomato, respectively.更多还原