Optimal gate operation of a main drainage canal in a flat,low-lying,agricultural area using a tank model

Chiyoda basin is located in Saga Prefecture in Kyushu Island, Japan, and lies next to the tidal compartment of the Chikugo River to which the excess water in the basin is drained away. Chiyoda basin has a total area of about 1,100 ha and is a typical flat and low-lying paddy-cultivated area. The main problem in this basin is the appropriate operation of drainage structures during and after flood events in order to minimize the inundation damages for crop yield and to fulfill the irrigation requirement in the irrigation period. This paper presents a mathematical model of a drainage system in Chiyoda basin for calculating the flood inundation and optimizing the operation of gates in a main drainage canal. First, the algorithm of gate operation was simulated and the drainage model was then evaluated by comparing the simulated water levels with those observed during an actual rainfall event. The results show that the observed and simulated water levels are in good agreement, indicating that the proposed model is applicable for drainage and inundation analyses in flat, low-lying paddy-cultivated areas. Second, the optimization of gate operation was investigated by trial and error method using a stochastic rainfall time series with a return period of 30 years and the tidal conditions of spring and neap tides in the Chikugo River. Comparing a total inundation time, a total inundation area and maximum inundation depth in the paddy tanks at the upstream and the downstream ends, it was concluded that the present operation based on the gate operators’ experience was almost the optimal one, and the sooner start of opening operation and the later start of closing operation within the operationality of check gates were recommended to minimize the inundation damage. The present operation could be able to minimize the total inundation time, the total inundation area and the maximum inundation depths in paddy tanks and to meet fully both the drainage and the irrigation requirements.     

田间条件下不同园龄茶树氮、磷、钾养分需求规律的研究

本文通过分析大田条件下1、2、3、5和10龄龙井43茶园头年秋天整株茶树、第二年采摘新稍、修剪物和落叶的生物量以及氮、磷、钾养分量,研究不同园龄茶树氮、磷、钾养分需求规律。1龄茶园到5龄茶园,茶树地上部生物量、氮、磷、钾养分量分别增加约32倍、21倍、25倍、29倍,到10龄茶园,与5龄茶园相比,仅分别增加约71%、17%、13%、14%。从1龄到2龄茶园,茶树氮、磷、钾的年养分需求量分别为90.01、5.71、31.11kg/hm2,从2龄到3龄茶园,茶树氮、磷、钾的年养分需求量分别为122.74、9.63、45.14kg/hm2,从3龄到4龄茶园,茶树氮、磷、钾的年养分需求量分别为144.03、10.33、47.99kg/hm2。幼龄茶树经过定型修剪后,吸收的养分有一部分通过修剪物和落叶回归土壤,因茶树生长(不包括修剪物和落叶等)并留存在茶树上的养分量占总量的43.9%、48.7%、61.3%左右。进入青年期,如5龄茶园,茶树氮、磷、钾的年养分需求量分别约为164.4、12.68、71.29kg/hm2。进入采摘后,茶树所需的养分主要用于新稍生长,一部分分配到修剪物和落叶之中,因茶树生长(不包括修剪物和落叶等)并留存在茶树上的氮、磷、钾养分量比较稳定且只占较少份额(氮、磷、钾养分量分别仅约为7.54、0.53、5.44kg/hm2)。本试验对田间条件下不同生育期的茶树氮、磷、钾养分需求量的研究建立了试验分析方法,为进一步研究茶树养分需求规律提供了一条新的思路。     

Systematic assessment of flood mitigation in a tank irrigated paddy fields area

Flood mitigation in irrigation tanks and paddy fields is their favorable aspect though its practical effect is not known very well. A dynamic and systematic approach is presented to assess flood mitigation in a tank irrigated paddy fields area in the worst case where no static buffer function is expected. Based on the linear control theory, transfer function models for runoff process in catchments are identified. Hydraulic models are developed to represent flood dynamics in irrigation tanks, paddy fields, and drainage channels. These models are integrated as an ordinary differential equations system. Then, using the perturbed linear system, flood mitigation in each component of the system is examined in terms of frequency response. An application example demonstrates that a tank irrigated paddy fields area has a significant flood mitigation effect as a low-pass filter. This method has the advantage of assessing flood mitigation even in the case of an increase in the total runoff ratio.     

闽江河口区稻田土壤和植物的C、N、P含量及其生态化学计量比

选取闽江河口区稻田为研究区域,对土壤和植物的C、N、P含量及其生态化学计量比进行测定和分析。研究表明：土壤C、N、P元素的变化范围分别为5.72-13.41、0.47-0.82和0.33-0.89 mg.g-1,平均值分别为9.50、0.62和0.56 mg.g-1,其C与N、C与P、N与P的比值分别为12.18-16.39、15.07-24.34和0.92-1.55,平均值分别为15.05、17.88和1.20;植物C、N、P元素的变化范围分别为28.62-38.99、0.65-1.52和0.13-0.32 mg.g-1,平均值分别为35.21、1.19、0.25 mg.g-1,其C与N、C与P、N与P的比值分别为24.54-44.10、94.05-258.93和2.13-10.55,平均值分别为32.11、160.07和5.47。土壤C、N含量低于植物,而P含量却高于植物,C与N、C与P、N与P的比值则表现为土壤低于植物。     

AA3型连续流动分析仪（CFA）同时测定橡胶叶全氮、全磷、全钾的方法研究

通过对AA3型连续流动分析仪所附试剂配制等方法的改进,研究AA3同时测定橡胶叶片氮、磷、钾的方法。结果表明,氮、磷、钾混合标准曲线相关系数均达0.999 9以上;氮、磷变异系数均小于0.5%(n=10),当钾浓度相当于标准曲线中间浓度范围时(即6～10 mg/L),变异系数为0.97%～1.13%,重现性良好;氮、磷、钾加标回收率分别为99.7%～101.1%、99.3%～100.7%、98.4%～102.8%,待测液中氮、磷、钾检出限分别为0.019、0.004、0.072 mg/L。橡胶叶片氮、磷、钾测定结果与常规法相比无显著差异。该方法用于橡胶叶片H2SO4-H2O2消煮后氮、磷、钾同时测定,快速高效,一天半可测300个样品待测液,提高工效10多倍。     

磷酸盐转运蛋白OsPT4影响水稻氮磷积累与利用的机理研究

【目的】磷酸盐(Pi)转运蛋白OsPT4是水稻Pht1家族成员之一,负责Pi吸收以及向地上部的转运。探究OsPT4超表达对不同Pi条件下水稻氮(N)和磷(P)积累与利用的影响及其机理具有重要意义。【方法】以日本晴背景的OsPT4超表达株系为研究材料,通过设置正常供Pi与缺Pi的水培与桶培实验,检测生殖生长阶段不同组织中OsPT4的相对表达量,探究不同Pi处理条件下不同组织(叶片、叶鞘、茎秆、稻壳、穗柄和糙米)中的N和P浓度,并计算Pi吸收率及N和P利用效率,同时分析株高、单株产量、千粒重和结实率等产量构成因素。【结果】OsPT4在水稻生殖生长阶段的根系中相对表达丰度较高,OsPT4超表达使水稻剑叶、叶鞘、茎秆、稻壳、穗柄和糙米中的总P浓度不同程度提高,并显著提高了不同Pi处理条件下的Pi吸收与利用效率。同时,OsPT4的超表达可显著提高正常供Pi与缺Pi土壤条件下的单株产量与千粒重,以及缺Pi土壤中生长的结实率。除此之外,OsPT4的超表达使缺Pi条件下瘪壳与糙米中总N浓度平均升高16.8%和19.8%,N利用效率平均升高6.6%。【结论】OsPT4超表达不仅显著提高Pi吸收与利用效率,同时对不同Pi条件下的生理氮素利用率起促进作用。     

灌水与施氮对夏玉米冠层结构及产量的影响

以郑单958为材料,在大田条件下研究不同水、氮处理对夏玉米冠层结构及产量的影响。结果表明,试验条件下,灌水使植株叶绿素含量（SPAD）增加、透光率减小,对产量无显著影响。施氮对冠层结构和产量的影响因灌水处理而不同,在不灌水条件下,增施氮肥增加叶片SPAD,提高穗位层叶面积指数（LAI）和产量,以施氮量375 kg/hm²时产量最高,较不施氮处理提高39.5%;在灌水条件下,增施氮肥增加各层LAI和SPAD,而使透光率减小,产量以施氮量225 kg/hm²时最高。氮肥偏生产力随施氮量增加呈明显下降趋势。从产量及氮肥高效利用看,高产玉米适宜的施氮量在225～300 kg/hm²之间,灌水与否取决于不同降水年型。     

水稻氮素的生物学特性及其高产运筹研究概况

本文着重对氮素营养与水稻生育特性、氮素与水稻群体的产量形成、氮素的吸收及其利用、水稻氮素高产运筹技术等进行了阐述,并提出了水稻氮素在栽培学与育种学研究上需要深入研究的几个方面,以其为今后水稻大面积生产上氮素的高效利用提供依据。     

施氮对小麦根-冠及土壤碳氮特征的影响

为解决小麦主产区土壤肥力下降、氮肥投入过量问题,在长期定位施氮试验基础上,研究了4个施氮水平（0、180、240和300 kg·hm^-2）下小麦根-冠生物量、碳氮含量以及麦田土壤碳氮含量、碳氮储量特征。结果表明,与不施氮处理相比,施氮可显著增加小麦的根-冠生物量和全氮含量,对根-冠有机碳含量影响不显著,但降低根-冠碳氮比;在180、240和300 kg·hm^-2三个施氮处理间,根-冠生物量、碳氮比及地上部氮含量均差异不显著,而根系氮含量则随施氮水平提高呈上升趋势。施氮对土壤有机碳含量和储量影响微弱,对20～40和40～60 cm土层的土壤氮含量和储量影响显著,且分别表现为随施氮水平的提高呈先降后升和先升后降趋势;从0~60 cm土层土壤碳氮含量平均值和总储量看,施氮效应不明显。由此可见,在本试验条件下,长期施氮可促进小麦生长和氮素营养供应,但对土壤碳氮含量和储量影响较小。     

Analysis of the water balance and the nitrogen and phosphorus runoff pollution of a paddy field in situ in the Taihu Lake basin

Paddy and Water Environment - Nitrogen (N) and phosphorus (P) runoff loads of paddy fields in situ under conventional water and fertilizer management measures caused severe water pollution in the...     

Nitrogen transport and transformation in packed soil columns from paddy fields

Our understanding of nitrogen transformation in paddy fields or wetlands is limited due to the complex interactions between soil, water, and biomass. Therefore, we studied transformation patterns resulting from the oxic level in the soil, and studied saturated (anoxic) and unsaturated (oxic) flow conditions. We present a model designed to predict concentrations of nitrate and ammonium at several soil depths resulting from the processes of nitrification, denitrification, and ammonification. Model equations were obtained that describe NO₃-N and NH₄-N concentrations in terms of position, rate constant, and average flow velocity. Although many parameters were included in the model equations, some were determined from the literature and others were derived from experiments. A sensitivity analysis of the rate coefficients for NO₃-N and NH₄-N revealed that they are extremely sensitive to denitrification and ammonification respectively. Experimental results show that there were large differences in the transformations of NO₃-N and NH₄-N, the water pressure distributions, and the oxygen reduction potentials (ORP) between saturated and unsaturated pore water flow conditions. The performance of the model for sequential transformations during the transport of NO₃-N is well documented under both saturated and unsaturated flow conditions.     

浅埋滴灌下水氮减量对春玉米干物质积累及水氮利用效率的影响

2017～2018年,以传统畦灌常规施氮为对照,采用大田裂区试验,以传统畦灌常规灌量40％(W1)、常规灌量50％(W2)、常规灌量60％(W3)为主处理,以常规施氮量50％(N1)、常规施氮量70％(N2)、常规氮施量(N3)为副处理,研究浅埋滴灌下水氮减量对春玉米干物质积累及水氮利用效率的影响.结果表明,浅埋滴灌下...     

不同水氮环境条件下小麦氮素含量和氮素利用效率的遗传模型研究

为了研究不同水氮环境条件下小麦氮素含量和氮素利用效率（NUE）的遗传模型,随机选用8个亲本组配成28个双列杂交组合,在正常和水氮亏缺胁迫两种环境下进行随机区组试验,采用Hayman的分析方法研究了各性状的遗传模型。结果表明,在正常环境下籽粒和茎秆的氮素含量为加性-显性-上住性模型遗传,叶片氮素含量和氮素利用效率为加性-上住性模型遗传。在水氮亏缺胁迫环境条件下,籽粒和叶片氮素含量为加性-显性模型遗传。茎秆氮素含量和氮素利用效率为加性-显性-上位性模型遗传。可见,小麦氮素含量和氮素利用效率的遗传模型在不同的水氮环境中不完全一样。     

不同拦截植物对小流域农田排水沟渠氮磷消纳效果差异研究

构建生态沟渠消纳水体氮磷是防控农业面源污染的重要措施.为筛选出适应湘北洞庭湖区农区沟渠生长的高富集氮、磷植物,选取津市市毛里湖稻区沟渠作为研究对象,进行生态沟渠拦截试验.于2016~2017年连续监测,系统研究狐尾藻、珍珠梅、海寿花等水生植物及组合对小流域农田排水中氮、磷的去除效果.结果表明:2年观测期(4~8月)内,拦截植物对农田排水总氮、铵态氮、硝态氮及总磷的去除率效应极显著(p<0.01),且去除率具有生长变化趋势.不同拦截植物及组合对总氮、铵态氮、硝态氮及总磷的去除率大小表现为狐尾藻+海寿花>海寿花>珍珠梅>狐尾藻>自然植被.其中,狐尾藻+海寿花组合平均总氮、铵态氮、硝态氮及总磷的去除率2016年分别为53.57%、77.35%、51.74%和61.06%,2017年分别为34.67%、66.53%、39.51%和46.05%.研究区生态沟渠对氮、磷污染物有较好的拦截效应,单种植物以海寿花的水体氮磷消纳效果较好,在此基础上混种狐尾藻,效果更佳.     

Infiltration process and groundwater table raising in a paddy field area

The water coming from the soil surface after the saturation of the soil stratum over the groundwater table at field saturation raises the groundwater level. The soil structure and the soil texture characterize the infiltration process. The resultant of the gravitational force and the capillary forces gives the energy to the water molecules to push the entrapped air out of the pores, reaching a full saturation of the soil thereby raising the phreatic level. There is a complex interaction between the agent forces on the water and the air resistant forces in the soil micro-pores. In the irrigation of paddy fields a groundwater level stable condition is reached when there is equilibrium between the capillary forces. A stable soil stratum with pressured air is always present in the soil over the phreatic level. From the collected data it seems that the soil stratum thickness from the soil surface to the groundwater table is proportional to the modulus of the capillary force. In a stable surface ponding depth, as the groundwater table rises, the level growing velocity may be assumed to be proportional to a medium hydraulic conductibility of the soil stratum. As the phreatic level approaches the saturated soil surface, the rising rate gradually changes until it gets to a point of equilibrium where the groundwater table is stationary at stable surface conditions. Under these conditions, as the surface water depth changes the phreatic level also changes.     

供氮形态和水分胁迫耦合作用对磷在苗期——分蘖期水稻植株不同部位含量与分配的影响

为探讨不同形态氮素营养对干旱条件下水稻P吸收与分配的影响, 采用室内营养液培养及聚乙二醇（PEG6000）模拟水分胁迫处理的方法,在分蘖期设置3种供氮形态（NH4+ N、NO3- N以及NO3- N和NH4+ N相同浓度下等体积混合）和两种水分条件（非水分胁迫及水分胁迫）的耦合处理进行研究。结果表明： 1）在水分胁迫条件下,水稻植株及各部位含P量均是全NH4+ N营养明显高于全NO3- N营养;同时,在分蘖期,全NO3- N营养水稻植株含P量明显低于非水分胁迫条件下的相应处理,但水分胁迫对全NH4+ N以及NO3- N和NH4+ N混合营养水稻含P量影响不大;2）在两种水分条件下,全NH4+ N以及NO3- N和NH4+ N混合营养均相对降低了水稻对吸收进入体内的P向叶片和根系的运输比例;而全NO3- N营养则只相对降低了水稻体内的P向叶片的运输比例。此外,由分蘖初期到中期,在水分胁迫条件下,全NH4+ N营养水稻积累的P素增加比例最高。     

以色列野生二棱大麦籽粒氮素含量的基因型及其生态差异

为了筛选极端蛋白质含量或氮素营养含量的大麦材料,以采自以色列不同生境的9个群体90个野生大麦基因型为试验材料,分别于2012年和2013年种植于黔中地区4个环境条件下（Y2012 Farm、Y2013 AS、Y2013 Garden和Y2013 9F）,测定并比较其籽粒可溶性蛋白质和总氮含量。结果显示,Y2012 Farm环境下的籽粒总氮含量显著高于Y2013 AS环境;Y2013 AS环境下的籽粒可溶性蛋白含量显著高于其他3个环境;在Y2012 Farm 和Y2013 AS两个环境下,籽粒总氮含量最高的是Tabigha群体,最低的分别是Golan High和Hermon群体,两者均与Tabigha群体有显著差异;Y2012 Farm、Y2013 AS及Y2013 Garden 3个环境中,Gilboa群体的可溶性蛋白质含量均显著高于其他群体,说明野生二棱大麦籽粒氮素营养积累既受种植环境的影响,又有一定的保守性。Y2012 Farm 和Y2013 AS两个环境下,总氮含量较高的基因型有T8、R23和R3,分别为3.42%、3.04%和3.12%,较低的基因型是GN26,平均值为2.01%。综合比较发现,在供试的野生二棱大麦基因型中,有利用价值的氮素含量极端高和低的基因型分别为T8和HM17,可用于现代栽培大麦的改良。     

氮、磷、锌营养对水稻籽粒植酸含量的影响及与几种矿质元素间的相关性

以协青早、秀水110及其辐射诱变获得的低植酸突变系（HIPi1和HIPj1）为材料,通过水培试验对不同氮、磷、锌浓度处理下水稻籽粒植酸含量差异及与几种矿质元素间的相关性进行了比较分析。高水平氮、磷、锌浓度处理的籽粒植酸含量较同一品种的低氮、磷、锌处理均有所降低,但在水稻生育期间,籽粒植酸含量对磷、锌处理浓度变化的敏感性,则因品种的植酸类型特征而异;氮、磷浓度增加能分别提高铁或降低铜在籽粒中的积累,但在高锌处理下,籽粒铁含量明显降低、而钾和镁的含量等却有所升高; 籽粒植酸含量一般与K、Mg、Fe、Cu 4种矿质元素含量呈正相关、与籽粒Zn含量呈负相关,但统计显著水平因品种而异。低植酸突变体籽粒中的K、Mg、Fe、Zn等含量虽略有下降,但可以通过适当的介质营养条件来调节有关矿质营养在水稻籽粒中的积累。     

Responses of C3 and C4 grasses to application of nitrogen and phosphorus fertilizer at two dates in the spring

In grasslands composed of C₃ and C₄ plants, a different pattern of response by the two photosynthetic types to fertilizer may change the floristic composition of the community. In this study, we evaluated the effects of an application of nitrogen (N) and phosphorus (P) fertilizer at two dates in the spring on the aerial growth of C₃ and C₄ grasses. Danthonia montevidensis and Stipa neesiana ( C₃), and Setaria geniculata and Sporobolus indicus (C₄), were selected from a native grassland of the Flooding Pampa, Argentina. Two consecutive experiments (early and late spring) were conducted in pots filled with the local soil. The C₃ grasses showed no response in aerial biomass, and only minor responses in aerial concentrations of N and P, numbers of leaves and tillers, and nutrient use efficiency to an application of P or N fertilizer. In contrast, their C₄ counterparts showed a consistent positive response. C₄ species performance was considerably influenced by date of fertilizer application in the spring. There was on average a 1·8 and a 2·5 increase in aerial biomass in early and late spring, respectively, to fertilizer application. The later date in spring was associated with higher ambient temperatures and it appeared that temperature rather than fertilizer application was the main limiting factor for C₃ species. It was concluded that the positive response in C₄ species to an application of P and N fertilizer indicates that the differences between C₃ and C₄ species were related to a higher demand to sustain greater growth rates in C₄ species.