【作者】 陈家宙；

【导师】 陈明亮；

【作者基本信息】 华中农业大学 ， 土壤学， 2001， 博士

【摘要】 季节性干旱缺水严重制约着我国红壤区农业的持续发展。1999～2000年在中国科学院红壤生态实验站，利用大型称重式蒸渗仪、测坑小区和径流小区，配合时域反射仪、光合蒸腾仪、水势仪及动态气孔阻力计等仪器，设计高、中、低3种土壤水分处理，进行了花生和早晚稻试验。结合“五水”转换观点和SPAC理论，系统地研究了红壤农田水量平衡、水分转换和作物的生产能力。研究结果为有效利用红壤区水资源、合理调控农田水分和提高作物生产力提供了科学依据和实用技术。 系统地阐明了赣中红壤农田年度和作物生长季节的水量平衡及各分量的特征。红壤区降水集中于3～7月，先于潜在蒸散高峰期的7～9月，农田向下排水集中于4～6月，形成深层蓄水，根系难以吸收，加剧了8～10月季节性水分亏缺对作物的危害。花生苗期和饱果期耗水少，花针期和结荚期耗水多，整个生育期必须有400 mm以上的水量才能满足需要。早稻本田期耗水量580 mm以上，生长期间降水总量能满足其需要，提出了“只排不灌”的高强度节水方式。晚稻本田期耗水量470 mm以上，生长期间的降水不足，必须灌水补充。 证实了中等土壤水分可以提高作物水分利用效率(WUE)和获得较高产量。长期低土壤水分使花生株形矮小、分枝减少、单叶面积及叶面积指数变小、后期叶片脱落快并且早衰，但细根增多。中、低土壤水分明显提高了花生叶片水平的WUE；中等土壤水分下花生根冠比和出仁率提高，水分临界期灌水可高产，而低土壤水分下花生大幅度减产。水稻中等土壤水分下的产量、叶片及产量水平的WUE都提高，早稻主要是因为颖花数和结实率增加，晚稻是因为增加了颖花数。 探明了SPAC中水流阻力主要以节点阻力存在，土-根阻力是决定作物水分状况的主要因素。花生植株体水势明显高于水稻对应部位的水势，红壤-作物-大气连续体水势绝对值大约以指数速率增加；水势差主要存在于土-根、茎-叶、叶-气界面，植株体阻力也主要以土-根和茎-叶节点阻力存在；叶-气界面阻力约占连续体内总阻力的90％以上，植株体阻力是土壤阻力的20～50倍。随着辐射增强，蒸腾速率变大，连续体内水流驱动力也增加。 较好地解决了作物生长与土壤水分运动的反馈及耦合关系的模拟问题。针对目前一些土壤水分运动模型的不足，建立了一个土壤水分运动与作物生产关系的计算机模拟模型，较好地实现了作物生长、根系吸水、蒸腾、蒸发、降水、入渗等各过程之间的联系，预测值与实测值吻合较好。模型在Excel中编写代码，使用方便并具有扩充件。更多还原

【Abstract】 The sustainable agriculture in Red Soil area of China is restricted severely by the seasonal drought and water shortage. During 1999-2000, the study was performed in the Ecological Experimental Station of Red Soil, Academia Sinica. Peanut or rice were planted in the large-scale weighing Lysimeter, pit plots, and standard runoff plots, where high, moderate, and low soil moisture levels were designed as 3 treatments, assembling with some instruments such as time domain reflectometry, portable photosynthesis system, dew point microvoltmeter, and porometer. Combining the "five waters" transition viewpoint and SPAC theory, the water balance, water transition, and crop productivity were studied. From the results, some scientific basis and practical techniques were provided for using water resource effectively, regulating farmland water rationally, and improving crop productivity.The characteristics of water balance and its components were expounded systematically both in years and in crop growing seasons. The precipitation was concentrated from March to July, earlier than the evapotranspiration peak-day, which was from July to September. The farmland downward water drainage was produced mainly during April to June, formed as deep soil layer water storage, which was difficult for crop root to absorb. And the hazard to crop, caused by the seasonal water shortage during August to October, was then intensified by it. The peanut physiological water-costing process presented as an unsymmetrical parabola, i.e., water amount consumed by peanut in seedling and pod-filling stages was less than that of in blooming and pod-setting stages. More than 400 mm water was demanded in the peanut full growth stage. More than 580 mm water was required by early rice after transplanting, and the total precipitation during the period was sufficient for the demand. The intensive water-saving pattern "drain only without irrigation" in early rice was then proposed. Later rice needed more than 470 mm water after transplanting, and the rainfall was far below the demand, so irrigation was crucial.It was approved that crop water use efficiency (WUE) was increased and the preferable yield was obtained in the moderate soil moisture. Under lasting low soil moisture, the peanut plant was short and small, tillers were reduced, leaf area and leaf area index were decreased, leaves were more easy to fall off and premature senility was showed in the late growth stage, but fine roots were increased. Under moderate soil water content, the peanut root/shoot ratio and kernel/pod ratio were increased, and high yieldcould be obtained if irrigation was performed during the water critical period. But the peanut yield was decreased by the large size in low soil moisture. The rice yield and WUE both in leaf and yield level were increased in moderate soil water content, for spikelets per panicle and filled spikelets were increased in the early rice, and spikelets per panicle were increased in the later rice.It was proved that the water flow resistances in SPAC existed largely as node resistances, and the resistance between soil and root was the major factor that determines the water status in crop. The water potentials in peanut plant were higher than that of in rice. The water potential differences were existed mainly in the interface of soil-root, stem-leaf, and leaf-air. And the resistances in plant were presented mostly as soil-root and stem-leaf node resistances. The water flow resistance in leaf-atmosphere interface account for more than 90 percent of the total resistance; and the resistance in plant was 20 to 50 times larger than soil. The water flow drive force was augmented with the increase of SPAC water flux, which was induced by the radiation.The problem of simulating the feedback and coupling relation between crop and soil water movement was solved in the study. After analyzing the disadvantage of some soil water movement models, a computer model was established to simulate soil water movement and crop growth. The complicated interrelatio更多还原