【作者】 肖新；

【导师】 胡锋； 赵言文；

【作者基本信息】 南京农业大学 ， 生态学， 2007， 博士

【摘要】 水资源与粮食生产发展的关系密切,如何提高农业生产中的水分生产力已成为21世纪人类面临的巨大挑战。我国是一个淡水资源严重短缺的国家,粮食安全始终是我国国家安全的重要内容。农业是用水大户,水资源压力与危机进一步加大,正成为制约我国农业发展的重要因素。南方丘陵区是我国重要稻米产区之一,季节性干旱的出现,致使水稻生产用水供给不足,严重阻碍水稻生产。而且水资源又具有区位固定性、不可替代性等特征,不像其它资源可以通过进口替代来缓解压力。因此,研究和开发节水农业,特别是节水的稻作农业,发展水稻节水生产,不但在很大程度上节约水资源,而且有利于增产稳产,节约能源和减少环境污染,对水资源日益短缺、人口压力巨大、又以稻米为主食的中国21世纪“稻米安全”具有特殊重要的战略意义。因此,探明节水稻作技术的生理生态特征和节水稻作模式的生态环境效应,建立适合于南方丘陵区季节性干旱地区的节水稻作技术与模式,旨在为该区稻作持续稳产高产高效优质生产和节约高效利用水资源提供理论依据。本研究以不同节水稻作技术和节水稻作模式为研究对象,在大田和防雨棚池栽条件下系统开展了节水稻作条件下水稻生理生态效应及技术体系集成、节水高效新型稻作模式生态环境效应及稻作模式的综合效益评价模型三方面研究。主要研究结果如下:1.阐明了节水条件下不同水稻品种产量效应及水分利用效率及节水对水稻产量构成和稻米品质影响。结果表明在早稻、中稻、晚稻节约用水分别达10%、28%、26%条件下,与其对照相比,引种早稻品种中旱27、中稻品种武运粳7号和两优培九、晚稻品种农香16和中香1号具有较高的经济与生态效益,在该区具有广阔的前景。节水灌溉对中稻与晚稻的生长和稻米品质的影响表现出一致性。与常规灌溉模式相比,节水灌溉下虽然水稻有效穗降低,有的甚至达到显著差异,但是每穗颖花数、结实率和千粒重的增加,弥补有效穗降低不足,因此产量变化未达到显著差异。节水灌溉条件下糙米率、精米率、整精米率、胶稠度、碱消值、直链淀粉等性状提高,而垩白率、垩白度、蛋白含量降低和稻米粒型变小。2.明确了控制灌溉下水稻密度与氮肥互作对其光合特性、稻谷产量及产量结构的影响。中稻试验结果表明,随着密度的增加,孕穗期前,控制灌溉水稻群体净光合速率增加,但孕穗期后,高密度大群体净光合速率衰退较快,与此同时,高密度大群体剑叶光合速率、穗粒数、结实率及千粒重较低;随着施氮量的增加,水稻群体净光合速率、剑叶光合速率、叶绿素含量、单位面积穗数及穗粒数增加,而结实率与千粒重降低。在本研究条件下,控制灌溉中稻水稻栽插密度为28.13万穴/ha、施氮量225kg/ha时,其产量最高,达10299kg/ha;控制灌溉晚稻栽插密度为32.14万穴/ha、施氮量225kg/ha时,其产量最高,达6537 kg/ha。3.揭示了不同水分胁迫程度下水稻产量构成因子及叶片生理性状指标相对值变化规律。大田试验结果表明,在轻度水分胁迫下,虽然有效穗数降低,但每穗颍花数和结实率增加能够弥补有效穗数降低不利因素,因此产量没有显著降低。在重度水分胁迫下,不仅有效穗数降低,而且每穗颍花数和结实率也降低,产量则显著下降。适当水分胁迫,能够不降低水稻的产量,大大节约灌溉水量,提高水稻水分利用效率,试验提出以-30kPa土水势为该区水稻节水灌溉控制标准。防雨棚池栽试验结果表明,在适宜土壤水分胁迫下,即土水势高于-30kPa,丙二醛(MDA)含量、细胞质膜透性、可溶性糖含量和游离氨基酸含量、SOD、CAT、POD含量相对值有所升高,当土壤水分低于灌溉下限复水至土壤饱和时,有所恢复,随着生育时期延长,变化趋势平稳,这说明叶片本身存在一定对干旱胁迫适应与调节能力。当水势低于-30kPa时,丙二醛(MDA)含量、细胞质膜透性、可溶性糖含量和游离氨基酸含量、SOD、CAT、POD含量相对值显著升高,抗旱性强品种的丙二醛(MDA)含量、细胞质膜透性增加或升高幅度小,抗旱性强品种可溶性糖含量和游离氨基酸含量、SOD、CAT、POD含量增加或升高幅度大。花后16天,细胞质膜透性、可溶性糖含量和游离氨基酸含量、SOD、CAT、POD含量相对值降低。4.阐明了节水稻作模式生态系统的物流、能流、价值流及生态环境效应。结果表明,节水稻作模式的净初级生产力为3.10×10~5-3.78×10~5MJ/(ha·yr),以化肥为主的辅助能投入为0.59×10~5-0.97×10~5MJ/(ha·yr),纯收入为484-1166美元/(ha·yr)。不同节水稻作模式所表现出的变化特征为:采用节水灌溉双季稻模式,有利于减少系统化肥、农药、人工等能量投入,增加系统能量的输出,提高能量转换效率、光能利用效率和稻田的经济效益;采用水旱轮作双季稻节水稻作模式,有机肥的投入增加,能流循环指数提高,系统稳定性增强,但能量转换效率下降,稻田的经济效益有所降低;采用稻油轮作节水稻作模式,在减少系统化肥、农药、人工等能量投入同时,充分利作物生长期间太阳辐射,光能利用效率提高,稻田的经济效益增加。与常规稻作模式相比,节水稻作模式的综合效益较高,具有较好节肥、省药效应以及控制农业面源污染效应。5.揭示了节水稻作模式需水规律和稻田水分利用效率。结果表明,节水稻作模式通过对水稻和油菜等作物产生的生长调控作用和补偿生效应,使植株蒸腾量、棵间蒸发量及稻田渗漏量大幅降低,各阶段的需水量、需水强度和需水模系数均发生显著变化,形成了稻作模式新的需水规律。与常规双季模式相比,节水灌溉双季稻模式、水旱轮作双季稻模式、稻油轮作模式的需水强度分别减少了0.76mm/d、1.15 mm/d、0.32mm/d,渗漏强度分别减少了0.12mm/d、0.16 mm/d、0.19 mm/d,水分利用效率提高了30%、48%、18%,作物需水与降雨耦合度分别提高了14%、33%、6%。6.阐明了节水稻作模式下土壤理化性状、土壤微生物特性及土壤酶活性变化规律。结果表明,与该区常规稻作模式相比,在试验设计范围内,节水稻作模式下稻田的土壤理化性状明显改善,随着耕种年限增加,土壤容重下降,而孔隙度增加,土壤通透性增强,有效阻止土壤次生潜育化和土壤酸化,提高了土壤pH值;采用节水稻作模式实现了土壤水分轻度亏缺,这种轻度水分亏缺不仅可以提供生命所必需的水分,而且可以有效地改善土壤的通气状况,为微生物的生命活动提供了良好环境,因此土壤微生物菌落总数的显著增加,其中以水旱轮作双季稻模式最佳;就土壤酶活性而言,节水稻作模式处理酶活性常规稻作模式相比,除转化酶外,其它酶活性均有不同程度的增加,尤其对磷酸酶与脲酶影响最大;主成分分析和相关分析表明,土壤脲酶、磷酸酶和过氧化氢酶活性与土壤化学性质显著相关,可以作为评价土壤肥力水平的指标,主成分分析能够客观地评价土壤肥力水平。7.构建了节水稻作模式综合效益评价模型与评价指标体系。针对南方丘陵区季节性干旱状况和稻作发展的基本特点,以节水稻作模式为研究对象,借鉴层次分析法(AHP)的基本原理,遵循科学、实用及简明的原则,构建了南方丘陵区节水稻作模式综合效益评价模型,提出了综合效益评价的经济效益、生态环境效益和社会效益三方面共16项评价指标。并以国家“863”项目推广示范的节水灌溉双季稻模式、水旱轮作双季稻模式、稻油轮作模式三种节水稻作模式和当地常规双季稻模式为例,利用所建模型进行了综合评价。结果表明,三种节水稻作模式的综合效益均优于该区常规稻作模式,以稻油轮作模式综合效益最高,因此在南方丘陵季节性干旱双季稻区适当发展稻油轮作节水稻作模式具有良好的前景。评价结果可为南方丘陵季节性干旱区水资源高效利用和稻作持续健康发展提供了理论依据。更多还原

【Abstract】 Distribution of precipitation is inconsistent and asynchronous with evaporation, creating conditions for severe summer and autumn droughts in the hilly region of southern China. Jiangxi Province is located in a hilly region of southern China, where seasonal drought regions are widely distributed. High temperatures have caused severe drought during the past fifty years. The drought disaster-affected acreage of rice was 0.63×10~6 ha in 2003. Seasonal drought often seriously affects rice production due to water stress. As a result, it is necessary to set up new water-saving rice cultivation systems to increase water use efficiency and reduce yield loss caused by drought. The physiology-ecological effect and technology integration of water-saving rice cropping, the feature of ecosystem function and eco - environmental effect of water-saving rice cultivation patterns, and synthetic evaluation mode of water-saving rice cultivation patterns were studied in the field experiment and trough cultivation experiment in this research. This research would lend itself to prove up more construction and function of water-saving rice cultivation systems, and set up sustainable water-saving rice cultivation systems. This research has the potential to aid in sustainable development and effective production of rice cultivation and optimum use of water in seasonal droughts hilly region of southern China. The results are as follows:The biological characteristics of introducing rice cultivars under condition of water-saving and effects of water-saving irrigation on rice growth and grain quality were studied by using 12 introducing rice cultivations and 3 local rice cultivations as material in the seasonal drought hilly region of southern China. The results showed the early rice, mid-season rice and late rice was under the condition of 10%, 28%, and 26% water-saving respectively, the introducing early rice cultivar Zhanghan 27, mid-season rice cultivar Liangyoupeijiu and Wuyunjing 7, late rice cultivar Nongxiang 16 and Zhongxiang 1 had higher economic benefit and ecological benefit, and had a bright prospect of application in the region. The effective panicle number and plant length in water-saving irrigation was lower than that in common irrigation, but the spikelet length, No. of spikelet per plant, seed setting rate and 1000-grain weight in water-saving was higher than that in common irrigation. Among which effects of water-saving irrigation on the effective panicle number, plant length and No. of spikelet per plant had notable discrepancy in some rice cultivars. Comparing with the common irrigation, the brown rice rate, milled rice rate, head rice rate, gel consistency, amylose content and alkali-spreading value was increased, but length/width, chalky grain rate and chalkiness was decreased. Therefore the rice grain quality could be improved in water-saving irrigation.The effect of amount of nitrogen and planting density on canopy apparent photo synthetic (CAP) rate, photosynthetic rate and chlorophyll content in flag leaves, yield components and grain yields were studied with indica hybrid rice Liangyoupeijiu in intermission irrigation in southern China seasonal drought hilly region. The results were as follows: as the increment of density, canopy apparent photosynthetic (CAP) rate increased before anthesis and decreased quickly during grain filling. Meanwhile photosynthetic rate in flag leaves, grain number per panicle, seed setting rate and 1000-grain weight decreased. As the increment of amount of nitrogen, canopy apparent photosynthetic (CAP) rate, photosynthetic rate and chlorophyll content in flag leaves, panicle number and grain number per panicle increased. But seed setting rate and 1000-grain weight increased. The result showed that the tiptop output of mid-season rice was 10299 kg/ha when the transplanting density was 281.3 thousand hills/ha and the applying amount N-fertilizer is 225kg/ha in controlling irrigation.In order to investigate the effects of drought tolerance on the yield, component factors, as well as water productivity of rice, the field experiment and trough cultivation experiment with rain-proof shelter were carried out in 2003 and 2004. The results followed that: irrigation when the soil water potential was higher than -30kPa had no significant effect on yield however would greatly save irrigation water and improve water productivity. It would be the optimal rice irrigation regime rice in this area. Meanwhile trough cultivation experiment with rain-proof shelter was carried out to investigate the effects of different water stress on the relative values of MDA, plasmalemma permeability, osmoregulation substances, protective enzyme activity. The results indicated that the relative values of MDA, plasmalemma permeability, soluble sugar, amino acid, and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in leaves increased and then decreased after rewatering to saturated soil under optimal water stress (the soil water potential was higher than -30kPa). The change trend became stable with the advance of growth stage. When the soil water potential was below -30kPa, the relative values of MDA, plasmalemma permeability, soluble sugar, amino acid, and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in leaves significantly increased, increases of MDA and plasmalemma permeability in better drought resistant cultivars were obvious less than those in weaker drought resistant ones, and increases of soluble sugar, amino acid, activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD in better drought resistant cultivars were obvious more than those in weaker drought resistant ones, and plasmalemma permeability, soluble sugar, amino acid, and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) decreased from16 days to 40days after anthesis. These results suggest that water stress can induce physiological and biochemical changes in rice and changes of MDA content, plasmalemma permeability, osmotic regulators and antioxidative enzyme activities are correlated significantly to drought resistance of rice varieties.Based on field investigation and experimental data analysis, ecological economic principles were applied to study the material flow, energy flow, value flow and ecological environmental benefits of water-saving rice cultivation systems. The results showed that the net production and economical production in the three types of water-saving rice cultivation systems were 3.10×l0~5 to 3.78×10~5MJ/( ha·yr) and 1.77×10~5 to 1.98×10~5 MJ/ (ha·yr), respectively. The major input of energy was for fertilizers, which were 0.59×10~5 to 0.97×10~5 MJ/ (ha·yr). The output-input ratios of energy and light utilization efficiency of rice fields were 3.22 to 6.45:1 and 0.64 to 0.78, respectively. The net monetary values were 484 to 1166 dollar/ (ha·yr) and the cost-benefit ratios were 0.34 to 0.88. Higher energy conversion efficiency, light utilization efficiency, and economic efficiency were found in the water-saving irrigation double-cropping rice cultivation system and water-saving rice cultivation system of rice and rape rotation. However, the lower energy conversion efficiency and economic efficiency took place in water-saving rice cultivation system of flood-drought cultivation. The water-saving rice cultivation systems had a higher integral benefit than the local rice cultivation system, and could significantly save water and decrease the application of fertilizer and pesticide so that it could control agriculture non-point resource pollution.Study of water-demand regulations and water use efficiencies under condition of different water-saving rice cultivation patterns were carried by field-scale experiments. The results obtained showed that the evapotranspiration of rice or rape reduced by a wide margin, the water requirement, requirement intensity and coefficient of every stage changed greatly for the growth regulation function and compensation effect to crop of water-saving rice cultivation patterns. Thus, the new water requirement rules of water-saving rice cultivation patterns were formed. The water requirement intensities of the water-saving irrigation double cropping rice pattern, the double cropping rice pattern of flood-drought cultivation, and water-saving rice cultivation pattern of rice and rape rotation were 0.76mm/d、1.15 mm/d、0.32 mm/d lower than those of the conventional double cropping rice pattern, respectively. The leakage intensities of the water-saving irrigation double cropping rice pattern, the double cropping rice pattern of flood-drought cultivation, and water-saving rice cultivation pattern of rice and rape rotation were 0.12mm/d、0.16 mm/d、0.19 mm/d lower than those of the conventional double cropping rice pattern, respectively. The WUE of the water-saving irrigation double cropping rice pattern, the double cropping rice pattern of flood-drought cultivation, and water-saving rice cultivation pattern of rice and rape rotation was 30%, 48%, and 18% higher than that of the conventional double cropping rice pattern, respectively.Environment of cultivated land has been influenced unfavorably by single continuous cropping in paddy field, and seasonal drought often seriously affects rice production due to water stress. The soil physical and chemical characteristics, soil microorganism and soil enzyme activity of water-saving rice cultivation patterns were studied in the field experiment of five years in this paper. The results showed that, water-saving rice cultivation patterns had improved soil physical and chemical characteristics apparently. Water-saving rice cultivation patterns could not only provide water indispensable to life, but also ameliorate the condition of soil water content and ventilation. Soil microorganisms multiplied, and the double cropping rice pattern of flood-drought cultivation was best among all the water-saving rice cultivation patterns. The activities of catalase, phosphatase, urease, polyphenoloxidase were higher than those of the conventional double cropping rice pattern. The correlation and principal component analysis showed that soil urease, alkaline phosphatase activities, and catalase activities could be as a comprehensive index of soil fertility, and their enzyme activities were affected by soil chemical properties and other enzymes. Soil fertility could be evaluated objectively by principal component analysis.Research of water-saving rice cultivation patterns integrated benefit evaluation is a core problem concerning development of paddy field agriculture, soil and water environmental protection as well as coordinated economic and eco-environmental development. Based on the current situation of seasonal droughts hilly region of southern China, applying analytic hierarchical process theory, this paper established the mathematical model and indicators system for integrated benefit evaluation for water-saving rice cultivation patterns by taking the demonstration patterns of water-saving rice cultivation in the native "863" special project as a research project. The evaluation indictors system was proposed based on characteristics and principles of scientific, practical and concise. The indicators system included three aspects such as economic benefit, social and eco-environmental benefit and systematically reflects the features of water-saving rice cultivation patterns. The evaluating model and the indicators system were applied to evaluate synthetically the integrated benefit of water-saving rice cultivation patterns in seasonal droughts hilly region of southern China. The evaluation results showed that The integrated benefits of the water-saving irrigation double cropping rice pattern, the double cropping rice pattern of flood-drought cultivation, and water-saving rice cultivation pattern of rice and rape rotation was higher than that of the conventional double cropping rice pattern, especially of water-saving rice cultivation pattern of rice and rape rotation. The evaluation model played an important role in the evaluation and management of water-saving rice cultivation patterns in seasonal droughts hilly region of southern China.更多还原