小麦叶片CO2/H2O交换参数 对不同供水条件的响应

Daily change of gas exchange parameter of wheat leaves was measured under different water conditions, the result have showed that, the photosynthetic rate, stomatal conductance, transpiration rate, and intercelluar CO₂ concentration are obvious change in daily. The trend of this change was differ from different water supply and it was influenced by many environment factors, such as soil water status, light, air temperature, and air humidity et al., but mainly determinated by stomatal conductance and photosynthetic characteristic of chloroplast.     

封丘地区小麦生产合理灌溉的研究: I.土壤水供给与小麦产量相关性分析

A 5-year experiment on water balance was conducted in a flat rainfed wheat field with an area of 66 m×100 m in Fengqiu, Henan Province, China. Results of the experiment showed that the correlation between wheat yield and water consumption was not significant, but that between wheat yield and the ratio of water supply to Penman evaporation was significant, following a parabolic curve. The water consumption process, as well as the growing season of wheat plant, could be divided into three periods. The first (154 days) was vegetative growth period, during which the water consumption accounted for 35% of the total; the second (65 days) reproductive growth period, during which the water consumption occupied 57%, indicating the importance of water consumption in this period; and the third (5~9 days) maturation period, during which water supply was not important to yield formation. According to the statistics of meteorological data over the years in this region, the hydrological conditions of the five seasons covered a probability range of 74.8%. The results (3.465.63 t ha^-1) indicated that the productivity of the wheat field under rainfed conditions in this region had a degree of confidence of 74.8%.     

土壤水分对小麦产量和品质的影响

本文综述了土壤水分对小麦产量和品质的影响。土壤水分既影响小麦产量,也影响其籽粒品质;土壤水分缺少能够影响器官发育,使叶面积减小,叶绿素含量降低,群体叶片光合性能下降。土壤水分缺少还使开花后的光合产物减少,造成灌浆物质不足,原贮存在营养器官中的物质向籽粒的运转速度加快,贮存物质在粒重中的比例提高,在一定程度上弥补了粒重和产量的降低。同时,土壤水分也影响小麦品质,主要表现在蛋白质和淀粉上。     

保水剂有效使用的土壤水分条件及对小麦的增产效果

在中壤质潮土,土壤水分含量在50%FMC～80%FMC范围内,应用保水剂拌种可使小麦出苗率增加,出苗期提前,麦苗抗旱性增强,地上部鲜、干重明显增加。田间小麦增产4.49%～6.09%。     

小麦叶片CO2/H2O交换参数对不同供水条件的响应

在大田不同供水条件下,于小麦孕穗期和灌浆期对小麦叶片气体交换参数的日变化进行了连续测定,结果表明,小麦叶片光合速度,气孔导度,蒸腾速度,以及叶肉细胞间隙ＣＯ２浓度均有较明显的日变化。不同供水条件下,Ｐｎ的日变化趋势不同,充分供水时为典型的双峰曲线,中午有明显的“午休”现象;当非充分供水时,Ｐｎ午休现象明显,且持续时间长,第二高峰表现不明显。     

小麦叶温对籽粒灌浆的影响

本文分析了叶温对小麦籽粒灌浆的影响.研究表明,叶温与气温的差能很好地反映小麦的灌浆过程.晴日,辐射充足,当植株水分满足时,叶气温差大,叶面积平稳下降,有利于籽粒灌浆.当太阳辐射充足,土壤干旱,小麦植株水分亏缺时,叶气温差小,植株早衰,叶面积大幅度下降,不利于籽粒灌浆.阴雨天,太阳辐射不足,气温低,叶气温差小,同样不利于籽粒的灌浆.并找出定量指标,生产上具有参考价值.     

小麦生死生长阶段综合温度指标研究

大量田间试验表明：温度是影响小麦生殖生长阶段（抽穗至成熟）长短的主要因子。粒花期与温度的关系一反“Ｓ”型阻滞曲线，有明显的阶段，其长适温为１６－１８℃；乳熟期与温度、日较差为非线性关系，其适宜温度１８－２２℃，日较差１０℃左右；完熟期与温度、日较差为非线性关系，其适宜温度为１８－２２℃，日较差１０℃左右；完熟期与温度、日差为线性关系其适宜湿度２２－２５℃，日较差７℃以上。     

水肥(氮)对小麦生理生态的影响 (Ⅰ)水肥 (氮 )条件对小麦光合蒸腾与水分利用的影响

光合速率在日出后随着光强的增强而急速升高,4月20日是小麦光合最强。净光合速率日变化随施氮量的增加而下降,水胁迫处理显著低于高水处理;不同时段变化净光合速率随施氮量和土壤含水量的增加而增加,但总的趋势是降低的。小麦蒸腾速率日变化总体趋势是在日出后随着光强的增强而急速升高、随光强的减弱而降低。小麦蒸腾速率日变化曲线为单峰型,中午最高。叶片蒸腾速率日变化随土壤水分供应增加而增加,随氮肥供应增加而下降;不同供水供氮条件下,叶片蒸腾速率的分异在日中尤其是上午比较明显。蒸腾速率从4月10日一直呈现下降趋势。小麦叶片水分利用率日变化曲线为"L"型,即早上较高,中午和下午都非常低。4月20日叶片水分利用率最高,5月10日最低。叶片对不同土壤水分和氮控制的反映为高氮低水高水分利用率,反之,则水分利用率较低。不同水、氮在上午对叶片水分利用率影响差异比较明显,下午则趋于一致。     

耐低钾冬小麦基因型筛选方法的研究

通过液培实验及低钾土壤上的田间实验,比较,讨论了耐低钾冬小麦基因型的筛选指标,时期及钾浓度,结果表明：液培筛选的评价指标,吸钾量优于钾利用指数,筛选的适宜时期为拔节期,钾浓度以１．０ｍｍｏｌ／ＬＫ＾＋为宜,低钾土壤７种基因型的经济产量与植株地上部吸钾量间存在极显著正相关（ｒ＝０．９４５,ｎ＝２１）。冬小麦吸收的钾主要来自于１ｍｏｌ／Ｌ热ＮＨＯ３不能提取的非交换性钾,吸钾量亦可作主田间筛选的评价指标     

薪炭林水土保持效益的研究

根据试验小区观测资料,本文分析了降雨量,雨强,土壤渗透及植物对水土流失的影响,结果表明:雨强是影响径流强度的主导因子,雨量是决定径流量的关键。建立植被,增强土壤入渗能力是防止水土流失的有效途径。     

A seasonal behavior of surface soil moisture condition in a reclaimed tropical peatland

Soil moisture condition is essential to regulate the release of soil carbon from a drained peatland since aerobic microbial activities can be encouraged through oxygen supply associated with dewatering the soil layer while they may be discouraged under too dry conditions. Aiming to characterize the soil moisture condition in a reclaimed tropical peatland, we monitored the volumetric water content at 5?cm depth (θ _5?cm), groundwater level (GWL) and rainfall for 20 months from March 2010 to November 2011 in an oil palm field in Nakhon-Si-Thammarat, Thailand. We also measured the soil water retention curve and the unsaturated hydraulic conductivity (k) for a series of matric potential (h) to simulate the moisture condition monitored in the field by using the Buckingham-Darcy's flux law. During the dry season in 2010, the θ _5?cm consistently stayed lower than 0.35?m³?m^–3 with the GWL lower than a depth of 30?cm. In the transition from the dry season to the rainy season in 2010, the GWL rose to the land surface with peaks and dips across the time for about one month with the θ _5?cm increasing toward saturation. During the rainy season where the GWL stayed near or above the land surface, the θ _5?cm remained the field-saturated value of 0.58?m³?m^–3 on average, less than the laboratory-saturated value of 0.63?m³?m^–3, suggesting the development of a significant amount of entrapped air-phase. Hysteretic behavior in the measured θ _5?cm–GWL relation also supported that the top soil layer refuses to absorb water in wetting processes. The simulated θ _5?cm based on the measured k(h) and soil water retention curves demonstrated that the ease with which the top soil dries during a dry season was due mainly to the low k(h) value in the dried condition, while the slope of the θ(h) curve was so moderate that the soil layer could retain moisture for maintaining liquid water supply to the surface from the dropped GWL. Sensitivity analyses while varying the magnitude of both k(h) and evaporation rate (E) suggested that the k(h) function was more deterministic than the value of E in making the land surface easily dried. As the GWL stayed lower than 30?cm in depth for a total of 187 days out of the year monitored, while surface-ponding conditions took place for 120 days of the year, it was concluded that either the extremely dried condition or the saturated-moisture condition had dominantly occurred in the study site through a year and, thus, there may only be a limited time when soil organic matter near the land surface is in favorable moisture conditions for aerobic decomposition.     

细质沙土增施磷肥对小麦生长及氮素吸收的影响

本文应用￣（１５）Ｎ示踪技术，在黄河故道细质沙土上研究小麦增施磷肥的效应。结果表明，增施磷肥，显著提高了小麦的根量、分蘖数、单位面积穗数和籽粒产量，促进小麦对肥料Ｎ和土壤Ｎ的吸收，减少肥料Ｎ损失，提高小麦对肥料Ｎ利用率。在该中低产沙地上，磷的施用量１８０～２７０ｋｇＰ２Ｏ５／ｈｍ２效益最佳。     

区域土壤盐渍化预报模型的初步研究

本文根据1987年春、夏季黄淮海平原曲周县北部247.4km²面积上,60个点的土壤盐分观测结果,结合前人的研究,详细分析了影响土壤盐分变化的各种因素,如土壤质地剖面(主要是粘土层厚度),地下水埋深及矿化度,降雨、灌溉和土壤初始含盐量,并以此为自变量,运用逐步回归分析方法,建立了春、夏季0-100和0-40cm土体盐分储量统计预报模型。逐步回归拟合的效果较好,主要影响因素都被选入预报方程,不同季节、不同深度土体选入方程的自变量各有侧重。初步检验证明,这种模型至少可满足农业生产中等级预报的精度要求。但预报模型只适用于与1987年相似年型及自然条件下。     

EFFECTS OF SPATIAL COUPLING OF WATER AND FERTILIZER APPLICATIONS ON ROOT GROWTH CHARACTERISTICS AND WATER USE OF WINTER WHEAT

□ Root systems play vital roles, inter alia in the acquisition of water and nutrients in all plants, and hence in their growth, physiology and metabolism. However, much remains to be learned about the mechanisms affecting root distributions and uptake efficiencies. These are important aspects to understand in order to optimize water and fertilizer applications, especially in arid areas such as the Loess Plateau of China, where a key crop is winter wheat. Therefore, we have studied the effects of spatial coupling of water, nitrogen and phosphorus applications on winter wheat root growth patterns at different growth stages and in different soil layers in soil columns. Observations by minirhizotrons showed root length, surface area, volume and number to be respectively 18.9, 25.3, 29.8 and 8.0% higher under dry treatments than under wet treatments. Simultaneous application of nitrogen and phosphorus in the 0–90 or 0–30 cm layers promoted extensive spatial distributions of roots, especially in the 0–30 cm layer. In addition, water use efficiency (WUE) was found to be strongly correlated with root length, surface area, volume and number (r ² = 0.72–0.80, n = 26), but weakly correlated with root biomass (r ² = 0.3).     

两种氮水平下CO2浓度升高对冬小麦生长和氮磷浓度的影响

预计到 2 1世纪末期大气CO2 浓度将会比目前水平增加 1倍 ,约 70 0 μmolmol- 1 左右。因此CO2 浓度升高对作物的影响研究十分重要。本文探讨在两种氮 (N)水平下 ,CO2 浓度升高对冬小麦 (TriticumaestivumL cv Xinong 872 7)生长和地上部N、磷 (P)浓度的影响及原因。试验设 3 5 0 μmolmol- 1 和 70 0 μmolmol- 1 两种CO2 浓度水平和 45kghm- 2 和 90kghm- 2 两种N肥施用水平。结果表明 ,CO2 浓度升高 ,冬小麦株高和叶面积指数 (LAI)均增加 ,净同化率 (NAR)值增加 ,叶面积比率 (LAR)下降 ,比叶重 (SLW )不增加。高CO2 浓度对相对生长率 (RGR)的影响因施N水平而异 ,低N时RGR不增加 ,高N时明显增加。CO2 浓度增加 ,小麦抽穗提早 7～ 8d ,叶鞘、茎杆和地上部干物重提高 ,叶片、叶鞘和茎杆N、P浓度降低 ,但叶片、叶鞘和茎杆N、P吸收量增加均不明显。CO2 浓度升高 ,氮磷利用效率 (NUE和PUE)提高 ,而对相对氮磷累积速率 (RNAR和RPAR)影响不大。高CO2 浓度冬小麦体内N、P浓度下降是由于稀释效应以及NUE和PUE提高之故。     

劣质水灌溉对土壤盐碱化及作物产量的影响

长期的劣质水灌溉将导致土壤潜在的次生盐碱化。通过在以色列的大田试验,分析了劣质水灌溉对浅埋地下水位条件下土壤盐碱动态和作物产量的影响。试验在安装有暗管排水系统的试验田中进行。试验田土壤为粉砂粘土,种植有饲料玉米(Zea mays L.)。试验结果显示,高盐碱地下水的侧向运动和蒸发形成了试验田南半部和北半部土壤中盐碱度分布的巨大差异。在试验条件下,0～1.2 m土壤中的盐分在整个玉米生长期内平均增加了7.5%,碱度增大了19.6%。作物产量和植株高度与土壤含盐量成反比,籽粒产量受影响最为严重。利用冬季的降雨淋洗土壤盐分是维持本地区灌溉农业持续发展的关键。     

基于CWSI和土壤水分修正系数的冬小麦田土壤含水量估算

2000年10月～2001年7月在西北农林科技大学灌溉实验站冬小麦田内,进行了利用作物冠层温度定量估算冬小麦田土壤含水量的试验研究。根据水分亏缺条件下作物蒸发蒸腾量计算公式及作物水分胁迫指标(CWSI)的定义,得到了基于CWSI和土壤水分修正系数Ks的不同生育阶段冬小麦田土壤含水量估算公式,其中Ks采用了康绍忠的幂函数形式(KM)及Dooreboos的线性公式(DM)。用该公式对冬小麦田土壤含水量在4个生育阶段进行了估算,并对估算值和实测值进行对比和误差分析。分析结果表明:在出苗越冬期和越冬返青期KM和DM模型对土壤水分的估算偏高,其原因是由于麦田土地裸露导致CWSI观测中出现了较大误差;在返青抽穗开花期和灌浆成熟期KM模型估算冬小麦根层土壤含水量较适宜,误差在15%以内,DM模型误差较大达到30%。