不同灌溉技术条件对冬小麦生产的影响

为了研究并得到3种不同灌溉技术（滴灌、喷灌、漫灌）对冬小麦产量及其构成的影响,在中国农业大学吴桥实验站设计了滴灌、喷灌、漫灌的大田试验.3种灌溉技术条件下,其灌溉总量相同,漫灌和喷灌采用浇底墒水加浇两水,滴灌采用浇底墒水加浇四水的方式;从冬小麦整个生长期内的作物高度、叶面积指数、籽粒重等指标,考察不同灌溉技术对冬小麦生产及其构成的影响.结果表明：滴灌条件下,表层含水量下降速度最小,整个生长期,含水量高于喷灌和漫灌;滴灌处理的叶面积指数最高,其次是喷灌;在成熟期,滴灌条件下,作物高度比漫灌高12%,比喷灌高5%;滴灌和喷灌的条件下产量分别比漫灌高8.63%,7.75%;滴灌、喷灌、漫灌的籽粒千粒重分别为43.36,42.17和41.17 g,滴灌和喷灌籽粒重明显高于漫灌,且生物量分别比漫灌提高了6.9%,3%.这说明3种灌溉技术中,滴灌技术最有利于实现节水保墒、小麦增产,其次是喷灌.     

粉碎秸秆对冬小麦棵间蒸发的影响

利用秸秆粉碎还田配施化肥(S)和常规施肥(R)2种措施下的大田试验数据,对比分析了2种措施下冬小麦全生育期内棵间蒸发量的变化,棵间蒸发量占蒸发蒸腾量的比例与叶面积指数的关系以及土壤含水量与叶片含水量的关系.结果表明:S,R 2种措施下冬小麦全生育内的棵间蒸发量变化均呈现为"大—小—大—小—大"的"W"型变化规律,相比较R措施,S措施可有效抑制冬小麦棵间蒸发,全生育期内平均抑制蒸发率为9.96%,抑制蒸发率随着生育期变化,呈现出"高—低—高—低"的趋势.同时冬小麦全生育期内S措施下的叶面积指数均高于R措施下的,棵间蒸发量占蒸发蒸腾量的比例均小于R措施下的,可见,S措施有利于叶片生长,并可减小棵间蒸发量占蒸发蒸腾量的比例.冬小麦封行后,通过监测40~60 cm和60~80 cm土层的土壤含水量可反映S,R 2种措施下冬小麦的水分状况.     

桶栽条件下冬小麦产量的连旱效应

为了研究连续干旱对冬小麦产量的影响,以冬小麦品种“矮抗58”为试验材料,通过桶栽试验,在冬小麦的拔节期、抽穗期和灌浆期分别设置轻度干旱、中度干旱、重度干旱,分别对应土壤含水率控制在田间持水率的60%~70%,50%~60%,40%~50%.试验设置了单阶段受旱9个、两阶段连旱6个,三阶段连旱4个,试验对照1个,共计20个试验处理.研究结果表明,单旱条件下,拔节期减产最明显,抽穗期其次;拔节期轻旱、中旱和重旱分别减产4.08%,21.71%和36.73%.两阶段连旱条件下,拔节期和抽穗期连续中旱对产量影响最大,减产率达28.42%;抽穗期和灌浆期连续中旱对产量影响相对较小.三阶段连旱条件下,连续轻旱减产不明显,连续中旱和重旱分别减产24.96%,53.99%.总体上,拔节期是冬小麦的需水关键期,中旱及以上水平就会引起显著减产;相反,水资源紧缺条件下,抽穗期和灌浆期可以适当中旱,甚至重旱,对产量影响较小.     

地下水位调控对冬小麦排水中氮磷浓度的影响

为了寻找减少氮磷流失的最优控水方式,采用田间试验研究不同地下水位控制对冬小麦地氮磷流失的影响.研究结果表明,不同控水方式对冬小麦地排水中氮磷浓度影响明显.经地下水位控制,冬小麦各生育期地下排水中的氨态氮(NH⁺₄-N)质量浓度降低,而硝态氮(NO^-₃-N)质量浓度则有所增加;拔节孕穗期保持水位100 mm处理排水总磷(TP)质量浓度增加,抽穗开花期排水TP质量浓度降低;拔节孕穗期保持水位-200 mm处理TP质量浓度降低,抽穗开花期则有所增加.冬小麦地土壤速效氮质量比在拔节孕穗期有所减少,抽穗开花期保持高水位有利于速效氮质量比降低,拔节孕穗期土壤中的速效磷质量比都有一定幅度的降低,抽穗开花期保持高水位有利于速效磷质量比降低,在水位较低的情况下,控水时间越长,速效磷质量比越大.     

Seasonal water use by winter wheat grown under shallow water table conditions

Techniques for estimating seasonal water use from soil profile water depletion frequently do not account for flux below the root zone. A method using tensiometers for obtaining evapotranspiration losses from the root zone and water movement below it is discussed. Soil water flux below the root zone is approached by a sequence of pseudo steady state solutions of the flow equation. Upward soil water flux contributed 36 to 73% to the total water requirement of winter wheat (Triticum aestivum L.) whereas soil water depletion accounted for 11 to 19% only. Water use efficiency with one irrigation during an early stage of plant development is greater than with no or three irrigations. This is the result of both decrease of resistance due to soil moistening and better root development. Tensiometer readings were also interpreted to estimate root zones, water table depths and soil moisture contents. Methods described in this paper can be used in determining seasonal water use by growing crops, replacing or supplementing lysimeter or meteorology approaches to this problem.     

灌溉水矿化度对土壤盐分及冬小麦产量的影响

为合理高效利用河北低平原区浅层地下咸水资源,采用田间试验的方法,系统研究了不同矿化度(1,2,4,6,8 g/L)灌溉水对土壤盐分分布与冬小麦产量的影响.结果表明,随灌溉水中矿化度的增加,0～20 cm厚度的土层土壤容重增加,同时土壤孔隙率逐渐降低.与淡水处理(1 g/L)相比,矿化度为2 g/L的灌溉水浇灌的麦田0～100 cm土层土壤平均盐分含量未出现明显增加;冬小麦拔节期、孕穗期和抽穗期的叶面积指数、株高以及单位面积穗数、穗粒数、千粒质量和籽粒产量未呈现明显差异.然而,当灌溉水矿化度增加到4 g/L以上时,0～100 cm土层土壤平均盐分含量大幅增加,植株生长受到明显抑制,籽粒产量出现显著下降,减产主要因素为咸水灌溉导致的冬小麦穗数减少.在该灌溉模式下,推荐冬小麦咸水灌溉的适宜矿化度低于2 g/L.     

基于熵权TOPSIS模型评价涝渍条件下冬小麦水位管理方案

为了选取基于资源、环境、效益相统一的水位调控方案,通过调节农田水位,制定了不同的排灌方案模拟冬小麦不同生育期的涝渍胁迫状况.将熵权法和TOPSIS模型有机结合,从冬小麦的高产、水资源的高效利用、减少农业面源污染3个方面选取4个指标构建冬小麦水位管理评价体系.通过熵权法确定各指标权重,运用TOPSIS模型对13种不同的水位管理方案进行计算,得到各处理的理论贴合度S_i,从而评价了各水位管理方案受到涝渍胁迫的影响.根据模型计算结果得出,冬小麦在乳熟期-200 mm(3 d)(5 d-800 mm)受涝渍影响最严重,造成产量下降明显;而在分蘖期-50 mm(1 d)(5 d-200 mm)受到涝渍胁迫时,可实现冬小麦高产、节水和减排的目标.结果符合试验规律,具有一定的实践价值.     

Estimation of a production function for wheat under saline conditions

Salinity is a major problem for irrigated agriculture in many parts of the world. Farmers face economic questions such as optimal water applications for given irrigation water quality, reuse of drainage water, reduction in income from using drainage saline waters and rate of mixing good quality water. Crop yield response to water quality and quantity is required to answer these questions. Therefore, this paper is concerned with estimating a set of production functions relating wheat yield to initial soil salinity and water quantity and quality. Crop-water production functions are estimated from experimental data from wheat crop at Sampla village in Rohtak district of Haryana (India).     

种植模式及灌水频次对冬小麦抗倒性的影响

为了研究高效节水灌溉模式对冬小麦抗倒伏能力和产量的影响,采用2种种植模式(宽幅精播种植和常规种植),每种种植模式设3种灌溉处理(拔节期、抽穗期和灌浆期各灌溉40 mm,拔节期和抽穗期各灌溉60 mm和拔节期一次灌溉120 mm),进行了灌溉频次和宽幅精播对冬小麦生育后期茎秆主要物理性状参数、机械强度、抗倒伏指数、产量及产量构成因素等的影响研究.结果表明,灌溉总量一定情况下,抽穗期、灌浆期和蜡熟期的冬小麦重心高度随着灌溉频次的增加而降低,3次灌溉对冬小麦茎秆倒数第二节间外径影响最大;1次和2次灌溉下常规种植倒数第二节间机械强度均显著大于宽幅精播,而3次灌溉下的抗倒伏指数均大于1次和2次灌溉;冬小麦茎秆机械强度和鲜质量呈显著相关,抗倒伏指数和重心高度呈显著负相关;无论何种种植模式均为2次灌溉下的产量最高,相对于常规种植模式,在减少灌溉频次的情况下,宽幅精播种植模式可以通过提高穗数发挥增产潜力.研究表明,统筹考虑冬小麦茎秆抗倒伏能力和籽粒产量,拔节期和抽穗期各灌溉60 mm和宽幅精播相结合是一种有效的节水种植模式.     

Effect of irrigation methods on root development and profile soil water uptake in winter wheat

The 2-year field experiments were carried out to research the effect of different irrigation methods, namely border irrigation, sprinkler irrigation, and surface drip irrigation, on root development and profile water uptake in winter wheat. Results showed that the main root distribution zone moved upward under sprinkler and surface drip irrigation when compared to the traditional border irrigation. Profile root distribution pattern changed with irrigation methods. Soil profile water uptake was correlated to the root system and soil water dynamics. Due to the appropriate soil water and higher root density in the surface soil layer under sprinkler and surface drip irrigation, the main water uptake zone was concentrated in the upper layer. Because of the water deficit in the surface layer under border irrigation, water uptake in 50–100 cm depth was stimulated, which caused the main uptake zone downward. The amount and pattern of root water uptake varied with irrigation methods. This may provide valuable information on the aspect of agricultural management.     

基于Cokriging插值修正冬小麦面积遥感监测

在研究区内冬小麦种植区选取149个地面样方,筛选样方内反映种植结构、地块破碎程度、地形因素的参数并利用差分GPS测量,对3个参数量化并确定插值的主辅变量。探讨和比较了利用普通克里格和协同克里格2种插值方法对研究区的冬小麦种植面积比例的插值结果。结果表明,相同采样数量下,协同克里格法相对于普通克里格法的均方根误差降低1.48%,预测值与实测值之间的相关系数提高了6.82%,利用COK插值获取研究区内冬小麦种植面积比例分布状况,可以分区域对大尺度冬小麦面积遥感提取结果进行修正。     

Modeling the role of irrigation in winter wheat yield,crop water productivity,and production in China

Irrigation plays an important role in increasing food production in China. The impact of irrigation on crop yield (Y), crop water productivity (CWP), and production has not been quantified systematically across regions covering the whole country. In this study, a GIS-based EPIC model (GEPIC) was applied to simulate Y and CWP for winter wheat (Triticum aestivum L.) in China at a grid resolution of 5 arc-minutes and to analyze the impacts of reducing irrigation water on wheat production. The findings show that irrigation is especially important in improving CWP of winter wheat in the North China Plain (NCP), the “bread basket” of China. On average, the provincial aggregate CWP was 56% higher under the irrigated than that under the rainfed conditions. The intensification of water stress and the associated increase in environmental problems in much of the NCP require critical thoughts about reducing water allocation for irrigated winter wheat. Two scenarios for irrigation reduction in the NCP provinces are presented: reducing irrigation depth (S1), and replacing irrigated winter wheat by rainfed winter wheat (S2). The simulation results show that S1 and S2 have similar effects on wheat production when the reduction in irrigation water supply is below 20% of the current level. Above this percentage, S2 appears to be a better scenario since it leads to less reduction in wheat production with the same amount of water saving.     

Response of wheat to saline irrigation and drainage

The response of wheat (Triticum aestiuum L.) to varying depths of irrigation, quantity of water applied and to the drainage conditions was studied in 2 m × 2 m × 2 m size lysimeters filled in with a sandy loam soil. Saline water with an electrical conductivity of 8.6 dS m⁻¹ was used for irrigation. The treatments included four irrigations of 5 cm depth, four irrigations of 7 cm, and three irrigations of 9 cm, scheduled on the basis of cumulative pan evaporation, while the drainage conditions were represented by the drained and undrained lysimeters. Another treatment, using good quality water for irrigation, represented the potential yield of the crop. The growth parameters, as well as the yield, showed an improvement with larger irrigation depth increments in the drained lysimeters. But, in contrast, in the undrained lysimeters, the yield was reduced with larger irrigation depth increments, mainly due to a sharp rise in water table depth during the irrigation cycles. The rise and fall in water table showed a high sensitivity and were also highly disproportionate to the irrigation and evapotranspiration events. The yield tended to be higher with a smaller depth of water applied more frequently in the undrained lysimeters. But, in view of the limitations of conventional surface irrigation to apply water in smaller depth increments, an improved drainage is imperative for cropping in shallow saline water table conditions.     

涝渍胁迫对冬小麦净光合速率变化的影响

在水位调控技术的基础上,采用田间试验研究了麦田水位调控下,冬小麦不同生育期、不同农田水层深度、地下水埋深下净光合速率变化规律.研究结果表明,淹水水位较浅且历时适中对冬小麦的净光合速率影响最小,相同水位、相同淹水历时条件下,水位回落速度越快净光合速率越大;不同控水条件下,冬小麦各生育期净光合速率日变化曲线呈“M”形.上午随光合有效辐射增强和温度的升高急剧增大,下午随有效辐射减弱和温度的降低大幅度下降,中午变化较缓,净光合速率峰值出现在11:00和13:00左右,12:00左右有明显的下降,即出现“午休”现象;此外,小麦净光合速率与光合有效辐射、太阳总辐射、大气温度、空气相对湿度和风速存在一定的相关性,其中净光合速率与太阳总辐射、光合有效辐射、空气温度有较强的相关性,与空气湿度和风速相关性较弱.     

覆膜冬小麦的生理生态效应研究

本文通过分析覆膜与不覆膜冬小麦的生理生态指标 ,总结了覆膜冬小麦的叶水势、光合速率、蒸腾速率等的变化规律 ,揭示了覆膜冬小麦节水、增产的机理 ,提出覆膜在不同生育阶段的不同效应情况 ,指出了适时揭膜的合理性。     

营养液供液量与供液频率对冬春茬辣椒的影响

为了了解营养液不同供液量和供液频率对辣椒生长发育、果实品质和水分利用效率的影响,以“洋大帅”为试验材料,采用基质槽培的栽培方式进行试验.试验设置了3个不同供液量(在苗期,每株辣椒每天的供液量分别为W1:300 mL,W2:400 mL,W3:500 mL,开花坐果期每株辣椒每天的供液量加倍,结果期每天的供液量是苗期的3倍)和3个不同供液频率(整个生育期,每天的供液频率维持不变,即T1:2次/d,T2:3次/d,T3:4次/d).结果表明:当供液量为W2时,地上部分与地下部分相关性最好;处理W1T2水分利用效率最高,为18.13 kg/m³,但是其产量最低;处理W3T1的总根表面积最大,为754.54 cm³;处理W3T2辣椒生长最好,有最大的株高和茎粗,果实品质与水分利用效率也相对较好.因此,处理W3T2为试验条件下基质培冬春茬辣椒最佳的供液量和供液频率.     

Modified steady state drainage equations for transient conditions in subsurface drainage

The steady state drainage solutions of Ernst, Dagan and van Beers were modified to predict the rate of fall (or rise) of water table midway between drain lines by using the integration technique of Bouwer and van Schilfgaarde. The same assumption to account for the non-uniformity of flux per unit area because of the change in the shape of the water table during recession, was followed.

The integrated equations of Ernst, Dagan and van Beers were compared with the integrated equation of Hooghoudt and of Toksoz and Kirkham which were developed by Bouwer and van Schilfgaarde and the non-steady equation of van Schilfgaarde, using the field data for falling water table collected from subsurface drainage experiment in the saline soil of Mundlana, India. From the comparison of predicted and actual hydraulic heads it was observed that all the equations showed good agreement. No specific trend for the behaviour of different equations could be found from the analysis of field observations at geographically different experimental locations given by Bouwer and van Schilfgaarde, Nwa and Twocock and El-Mowelhi and Hermsmeier.     

灌水控制下限对冬小麦产量和品质的影响

为制定冬小麦的优质高效灌溉指标,通过3个生长季（2005－2008年）的人工控水试验,研究了不同灌水控制下限对冬小麦生长、产量和品质的影响。结果表明,与对照相比,播种—拔节前期水分胁迫对冬小麦生长、产量及品质的负面影响不明显,且可节水11.68%～18.18%,水分利用效率提高8.33%～12.5%;拔节—抽穗前期水分胁迫对冬小麦生长的抑制作用最明显,使籽粒出粉率、蛋白质质量分数显著降低,面团形成时间和稳定时间显著缩短,产量降低6.56%～9.08%,但可节水24.29%～31.95%,水分利用效率提高6.19%～10.63%;抽穗扬花期水分胁迫对冬小麦生长没有明显影响,虽显著提高了籽粒蛋白质、湿面筋、氨基酸质量分数和出粉率,但减产9.96%～11.35%,水分利用效率仅提高了4.12%～5.62%;灌浆成熟期水分胁迫对冬小麦生长影响最小,籽粒蛋白质、湿面筋、氨基酸质量分数和出粉率均显著提高,但大幅度降低了产量,水分利用效率只提高了1.03%～5.95%。华北地区冬小麦优质高效节水灌溉指标是：播种—拔节前期、拔节—抽穗前期、抽穗扬花期和灌浆成熟期的灌水控制下限分别为50%、65%、70%和65%田间持水率。     

基于主成分和云模型的冬小麦种植信息提取研究

在对Sentinel-2卫星遥感影像进行预处理的基础上，利用主成分变化提取小麦主要信息，基于云模型算法开展光谱遥感图像分类。分类时，首先根据训练样本集，由逆向云发生器生成典型小麦的云模型，然后利用云发生器计算出各波段每个象元对小麦地物的平均隶属度，在对各波段的隶属度分析基础上，摒弃含有复杂信息的第1主成分，利用第2主成分和第3主成分信息实现对冬小麦种植空间信息的提取。结果表明，提取小麦种植信息制图精度和用户精度分别为92.78%和99.90%，小麦种植田块的隶属度值因小麦长势和密度的不同有较大的差异，云模型对长势较差、密度较低的小麦像元存在漏分现象。基于云模型的算法精度极高，对小麦地块的识别错分、漏分现象少。该模型有助于冬小麦种植面积的精确提取，对于农业部门进行冬小麦生长监测与产量估测有重要的支撑作用。      

基于SIMDual_Kc模型估算非充分灌水条件下冬小麦蒸散量

为研究关中冬小麦植株蒸腾和土壤蒸发规律,利用2 a冬小麦小区控水试验实测数据,率定和验证了双作物系数SIMDual_Kc模型在关中地区的适用性.用大型称重式蒸渗仪的实测蒸散量值(或水量平衡法计算值)与模型模拟值进行对比.结果表明:SIMDualKc模型可较准确地模拟关中不同水分条件下冬小麦蒸散量,且模拟精度较高.模型估算的平均绝对误差为0.643 3 mm/d.模型估算的冬小麦初期、中期和后期的基础作物系数分别为0.35,1.30,0.20.另外,模型还可以较准确地估算不同水分供应条件下的土壤水分胁迫系数、土壤蒸发量和植株蒸散量.冬小麦整个生育期,土壤蒸发主要发生在作物生育前期,中期较低,后期略微增大;植株蒸腾主要发生在作物快速生长期和生长中期,整个生育期中呈先增大后减小的趋势.