The rectangular hyperbola (RH), Mitscherlich (M) and YE equation were applied to describe the photosynthetic light response (PLR) curves measured from rice leaves with different SPAD values, to reveal the relationship between SPAD values and parameters in different equations, and to establish the modified PLR equations. The parameters in PLR equations are largely varied. SPAD value, as an indicator of leaf N contents, was highly correlated to the parameter of P-nmax in RH, M and YE equations. Incorporating the factor SPAD into PLR equations, the modified equations (MRH, MM, and MYE) were established which were feasible to describing the PLR curves for leaves with different SPAD values using the identical parameters for the ten PLR curves as a whole, and perform much better than the general PLR equations (GRH, GM, and GYE). It indicated that incorporating easy available indicators of leaf physiological and morphological traits in the PLR equations, such as SPAD as an indicator of leaf N or Chlorophyll contents, is an easy way to overcome the shortcoming of parameters variation in PLR equations between individuals of the same specie growing in different environments. Further validation should be done for different crops with both SPAD and other possible factors.

Impact of water deficit in different growing stages on rice growth was disscussed based on the change of dry matter and yield of rice under water regulation and different nitrogen levels from pot experiments.The results showed that the yield of rice was not significantly decreased and dry matter accumulation was slightly increased with water deficit during later tillering stage compared to check treatment,but rice is easy to be restrained from water deficit during jointing-booting and head-flowering stages,especially under water deficit during heading-flowering,the yield and dry matter accumulation were significantly decreased compared to check treatment.Nitrogen level would regulate crop growth under water deficit.High level of nitrogen can improve water use efficiency,release the damage to rice under water deficit,and realize the effect of water-fertilizer mutual coordinated.

概述了国内外高效节水灌溉的发展状况,阐述了各种灌溉方式的适用对象及优缺点,以期为以后的发展提供借鉴和参考。

In order to determine the compensation effects of rewatering of the water deficit,pot experiments were carried out to study the influences of the lower limit of soil moisture of around rice with different nitrogen levels at different bearing periods on growing characteristics. The results show that,with different nitrogen levels,the dry matter production of roots and shoots,allometric growth between roots and shoots,rice yield,and water and fertilizer utilization efficiency exhibit significant differences with the water stress stage. Rewatering of the water deficit at the late tillering stage results in significant compensation effects. The rewatering of severe water deficit (saturated water content of 40%) has lesser influence on the rice growth at the late tillering stage with a high nitrogen fertilization level (300 kg/hm2),and it may be regarded as a reasonable control index for rice.

A leaf-scale coupled approach to photosynthesis-stomatal conductance modeling is a key element in predicting physiology of crop, estimating crop growth and water use. In order to consider the effect of moisture and nitrogen deficit of soil on stomatal conductance and photosynthesis, the leaf-air temperature and chlorophyll relative content were introduced to regulate coupled Leuning-Ball photosynthesis-stomatal conductance model. Field data of a pot experiment were used to validate the model. The results show that the improved coupled model yields reasonable interpretation and the best photosynthesis interpretation ability under soil moisture and nitrogen deficit. For stomatal conductance, the maximum relative errors were reduced from 125.5% and 128.8% to 98.2% and 126.6%. For photosynthetic rate, the average relative errors were reduced from 32.3%, 74.3% to 20.5% and 39.3%, and the maximum relative errors from 331.5% and 327.9% down to 113.4% and 177.1%, respectively. The coupled model can reflect the water and energy situation considering the limiting water and nitrogen more reasonably.

In order to find an effective coupling effect of water and fertilizer and reduce non-point pollution,nitrogen transportation,dynamics and pollution in paddy field as affected by different levels of water and fertilizer are investigated by analyzing surface water and soil solution samples.The experiments are conducted in lysimeters and TN、NO-3 and NH+4 are analyzed during the whole season of rice growing.The results indicate that the value of contamination concentration reaches to the peak ten days after fertilizing,then drops rabidly and last approaches to a steady state.The drainage should be regulated in order to reduce the runoff of nitrogen.As affected by different level of water and fertilizer,the feature of NO-3 and NH+4 concentration is different in surface water and soil solution.The pollution produced by nitrogen in surface water in paddy field can be decreased by control irrigation,and the concentration in soil water is higher than traditional irrigation,however,the total leaching is lower.Overall,the pollution can be efficiently reduced by control irrigation.Under traditional irrigation,the effect of different levels of fertilizer on concentration of N is not obvious,but under control irrigation,the concentration of site-specific nutrient management(SSNM) is higher than farmers' fertilization practice(FFP).It can be concluded that the concentration of control irrigation and SSNM is an effective way for reducing nitrogen leaching.

通过不同肥料和密度对杂交棉主要农艺性状的影响研究,结果表明,在22500～31500株/hm2的密度水平和600～1050kg/hm2的施肥(折尿素,下同)水平范围内,各处理对杂交棉的生育期影响不大;而随着密度增加,杂交棉每株果档数减少、单铃重下降、衣分降低,有效铃增加,产量总体上呈增加趋向势;随着肥料水平增加,不同密度水平的产量性状因子表现不一致,,而较低密度时,除每株果档数外其余产量性状及产量均增加,而较高密度时,各产量性状及产量则表现先增后降,但差异不明显,均在杂交棉移栽种植的适宜密度范围内.综合来看,生产上应以27000株/hm2密度和900kg/hm2施肥水平为基础上,视田间具体条件,选择适宜的肥料和移栽密度水平.

基于蒸渗仪试验中水样采集与室内水质化验资料，研究了不同水肥条件对稻田氮素运移的影响及不同土壤深度氮素浓度的变化规律，分析了不同水肥组合对环境污染的影响。结果表明，不同水肥条件下氮素浓度总体呈现施肥后10天出现峰值，之后迅速下降，并逐渐趋于稳定的变化规律。减少施肥后10天内的排水量是降低氮素随径流流失的有效途径。控制灌溉可以减少稻田中氮素对地表水的污染，而土壤溶液中氮素浓度略有增加，但总淋失量小于淹灌。因此控制灌溉可以有效减少氮素对环境的污染。淹水条件下施肥水平对氮素浓度影响不显著，而控灌条件下实地施肥氮素浓度略高于常规施肥。综合水肥因素的共同作用，控制灌溉实地养分管理是减少稻田氮素淋失的较优水肥组合。

通过蒸渗仪试验和室内化学分析，研究了不同水肥调控模式下水稻叶片叶绿素含量、PSⅡ最大光化学量子产量Fv/Fm和PSⅡ潜在活性Fv/F0的响应规律及相应参数的补偿效应。结果表明，控制灌溉实地施肥水稻Fv/Fm 和Fv/F0正午低于对照，正午前后接近或高于对照，适度的水肥调控增强了叶片抵御光抑制的能力；控制灌溉实地施肥水稻各时刻的Fv/Fm和Fv/F0在拔节孕穗期后多接近或高于对照，控制灌溉水稻叶片叶绿素含量具有拔节孕穗后期到乳熟前期多高于对照的变化规律，适度的水肥调控提高了水稻叶片光能利用效率与叶绿素含量。生长中后期表现出明显的生理补偿效应，有利于水稻光合产物的积累及获得较高的经济产量。