In situ measurements of winter wheat diurnal changes in photosynthesis and environmental factors reveal new insight into photosynthesis improvement by super-high-yield cultivation

In past 30 years, the wheat yield per unit area of China has increased by 79%. The super-high-yield(SH) cultivation played an important role in improving the wheat photosynthesis and yield. In order to find the ecophysiological mechanism underneath the high photosynthesis of SH cultivation, in situ diurnal changes in the photosynthetic gas exchange and chlorophyll(Chl) a fluorescence of field-grown wheat plants during the grain-filling stage and environmental factors were investigated. During the late grain-filling stage at 24 days after anthesis(DAA), the diurnal changes in net CO_2 assimilation rate were higher under SH treatment than under high-yield(H) treatment. From 8 to 24 DAA, the actual quantum yield of photosystem II(PSII) electron transport in the light-adapted state(ΦPSII) in the flag leaves at noon under SH treatment were significantly higher than those under H treatment. The leaf temperature, soil temperature and soil moisture were better suited for higher rates of leaf photosynthesis under SH treatment than those under H treatment at noon. Such diurnal changes in environmental factors in wheat fields could be one of the mechanisms for the higher biomass and yield under SH cultivation than those under H cultivation. ΦPSII and CO_2 exchange rate in wheat flag leaves under SH and H treatments had a linear correlation which could provide new insight to evaluate the wheat photosynthesis performance under different conditions.     

土壤深松和补灌对小麦干物质生产及水分利用率的影响

研究一次深松耕作后土壤水分对冬小麦籽粒产量和水分利用率的影响,为小麦节水高产栽培提供理论依据.于2008-2009和2009-2010两个小麦生长季,选用高产小麦品种济麦22,采取测墒补灌的方法,研究了深松+旋耕和旋耕2种耕作方式下土壤水分对小麦0-200 cm土层土壤含水量、干物质积累与分配、籽粒产量及水分利用率的影响.结果表明,(1)深松+旋耕40-180 cm土层土壤含水量低于旋耕处理;旗叶光合速率和水分利用率,开花后干物质积累量及其对籽粒的贡献率显著高于旋耕处理.(2)W3(补灌至0-140 cm土层土壤相对含水量播种期为85％,越冬期80％,拔节和开花期75％)成熟期0-200cm土层土壤含水量与W1(播种期80％,越冬期80％,拔节和开花期75％)和W2处理(播种期80％,越冬期85％,拔节和开花期75％)无显著差异;W3和W''3(播种期85％,越冬期85％,拔节和开花期75％)60-140 cm土层土壤含水量分别低于W4(播种期85％,越冬期85％,拔节和开花期75％)和W''4(播种期90％,越冬期85％,拔节和开花期75％)处理;W3和W''3灌浆中后期旗叶光合速率较高,开花后干物质积累量及其对籽粒的贡献率显著高于其他处理,获得高的籽粒产量和水分利用率.综合考虑籽粒产量、水分利用率和灌溉效益,在深松+旋耕条件下,两年度分别以W3和W''3为节水高产的最佳处理.     

基于AquaCrop模型的北京地区冬小麦水分利用效率

【目的】作物水分利用效率(water use efficiency,WUE)是农业水分管理与决策的重要指标。北京是严重缺水的城市,其主要种植作物冬小麦灌溉用水占比高,开展冬小麦产量水分利用效率的分析研究,可为北京地区的冬小麦节水灌溉与增产平衡提供决策信息支持。【方法】利用2011—2012、2012—2013和2013—2014年国家精准农业示范研究基地冬小麦不同生育期不同灌溉处理下的田间实测数据,对AquaCrop作物模型进行参数本地化。统计北京地区2004—2014年冬小麦生育期的日降雨量数据,利用Pearson-Ⅲ型分布划分了3种降雨年型:湿润年(2012—2013年生育期)、平水年(2009—2010年生育期)和干旱年(2005—2006年生育期)。应用AquaCrop研究分析了3种不同降雨年型、14种灌溉情景下冬小麦籽粒产量水平和产量水分利用效率特征变化。【结果】基于AquaCrop模型的产量模拟值和实测值的R 2、RMSE和d分别为0.99、0.3 t·hm~(-2)、0.99。模型模拟的冬小麦产量水分利用效率:2011—2012年正常灌溉条件下为1.72 kg·m~(-3),2012—2013年正常灌溉条件下为1.67 kg·m~(-3),2013—2014年雨养、正常灌溉和过量灌溉条件下分别为1.27、1.74和1.64 kg·m~(-3),正常灌溉条件下产量水分利用效率最高,其次是过量灌溉,雨养条件下产量水分利用效率最低。在此基础上应用AquaCrop模型模拟分析了3种不同降雨年型冬小麦籽粒产量和产量水分利用效率随灌溉量变化的响应特征,其中,湿润年产量水分利用效率和籽粒产量达到最大值时所需的灌溉量分别为35和50 mm;平水年达到最大值所需的灌溉量分别为35和40 mm;干旱年达到最大值所需的灌溉量均为65 mm。【结论】AquaCrop模型可以很好预测北京地区不同年份不同灌溉条件下冬小麦的籽粒产量和产量水分利用效率。冬小麦产量与产量水分利用效率均随着灌溉量的增加逐渐增大,至最大值后开始减小,在干旱的情况下,植物通过自身适应策略会提高水分利用效率,随着水分的增加,水分利用率将降低,因此3种不同年型的产量水分利用效率的大小顺序依次为干旱年、平水年和湿润年。因此,在制定冬小麦灌溉策略时,要做到产量和产量水分利用效率兼顾。以上研究结果表明,利用Aqua Crop模型可以为北京地区冬小麦田间灌溉和决策提供指导。关于降雨年型本研究仅对湿润年、平水年和干旱年3种年型在越冬期、返青期、拔节期、开花期和灌浆期不同灌溉量和籽粒产量和产量水分利用效率之间的关系进行模拟,对于不同时期不同灌溉量对籽粒产量和产量水分利用效率的影响没有考虑,需要进一步研究验证。     

渭北旱塬不同施肥与覆盖栽培对冬小麦产量形成及土壤水分利用的影响

 【目的】研究不同施肥和覆盖栽培模式对渭北旱塬旱地冬小麦产量和水分利用的影响。【方法】通过田间试验,研究测土推荐施氮、顶凌追肥、垄覆沟播、秸秆还田覆盖等措施对冬小麦产量、生物量、收获指数、水分利用效率及土壤水分周年变化的影响。【结果】旱地早春追肥使冬小麦增产6%—14%,水分利用效率提高7%—10%,达到12.2—13.6 kg•hm-2•mm-1;“减氮+垄覆沟播”增产达15%—41%,水分利用率提高10%—30%,达到12.2—16.5 kg•hm-2•mm-1。主要原因是,通过测土优化氮肥用量,采用基肥﹕追肥（3﹕1）方式,并与起垄覆膜栽培措施相结合可促进冬小麦利用深层土壤水分,提高冬小麦抽穗开花期植株含水量和成熟期的生物量及收获指数;虽然生育期耗水增加,但水分利用效率也提高。而单纯减少氮肥用量,不利于水分利用效率的提高;夏季垄上覆膜沟内覆盖作物秸秆可提高休闲效率,利于土壤水分恢复,实现土壤水分周年平衡和旱地小麦可持续增产。【结论】优化施氮结合垄覆沟播是黄土高原渭北旱地小麦增产增效的栽培模式。     

深松蓄水和施磷对旱地小麦产量和水分利用效率的影响

【目的】针对黄土高原旱地小麦干旱缺水、肥料不合理施用的问题,探索旱地小麦休闲期深松蓄水和播前配施磷肥的最佳技术途径。【方法】于2012—2016年连续4年在山西农业大学闻喜旱地小麦试验基地开展试验,主区为休闲期深松与对照2个耕作方式,副区为施磷(P_2O_5)0、75、150、225、300、375 kg·hm~(-2) 6个施磷量处理,以明确年际间休闲期深松和播前配施磷肥对旱地小麦产量和水分利用效率的影响。【结果】夏季休闲利于旱地麦田土壤水分恢复,可提高土壤蓄水效率20%—86%;休闲期深松较对照显著提高播种期3 m内土壤蓄水量24—90 mm;提高穗数1%—18%,提高产量3%—25%,提高2012—2013年水分利用效率4%—20%。施磷肥对土壤水分有一定影响,施磷量在0—225 kg·hm~(-2)范围内,旱地小麦生育期内0—300 cm土壤蓄水量以施磷量150 kg·hm~(-2)最低;施磷(4年定位试验)降低了生育期内0—300 cm土壤蓄水量,各处理间差异以第4年最显著。本试验中施磷肥的第3年和第4年的土壤水分未达平衡,施磷量150 kg·hm~(-2)与未施磷肥间的周年耗水量差异显著,说明长期施磷肥增加了作物对水分的消耗和利用,0—300 cm土壤蓄水量会降低。随施磷量(0—225 kg·hm~(-2))增加,旱地小麦4年平均产量和水分利用效率表现为先增加后降低的变化趋势,并且均以施磷量150 kg·hm~(-2)最高,产量各处理间差异显著,水分利用效率施磷量150 kg·hm~(-2)与未施磷肥处理间差异显著。此外,F测验显示年份对产量和水分利用效率影响最大,增产效果显示休闲期深松的增产效果高于磷肥的增产效果,最终4年定位试验形成的播前0—300 cm底墒414—546 mm配施磷量150 kg·hm~(-2)、底墒556—607 mm配施磷量75 kg·hm~(-2),穗数、产量、水分利用效率均较高。【结论】旱地麦田休闲期深松有利于蓄积休闲期降水,改善底墒;施磷增加了旱地小麦对土壤水分的消耗和利用,降低了生育期土壤水分,增加了周年耗水;休闲期深松每多蓄1 mm水分可增产2—31 kg·hm~(-2),在施磷量0—150 kg·hm~(-2)范围内每多施1 kg·hm~(-2)磷肥可增产2—13 kg·hm~(-2);播前0—300 cm底墒550 mm以下配施磷量150 kg·hm~(-2)、底墒550 mm以上配施磷量75 kg·hm~(-2)均可实现较高的产量和水分利用效率。     

A simulation of winter wheat crop responses to irrigation management using CERES-Wheat model in the North China Plain

To improve efficiency in the use of water resources in water-limited environments such as the North China Plain(NCP), where winter wheat is a major and groundwater-consuming crop, the application of water-saving irrigation strategies must be considered as a method for the sustainable development of water resources. The initial objective of this study was to evaluate and validate the ability of the CERES-Wheat model simulation to predict the winter wheat grain yield, biomass yield and water use efficiency(WUE) responses to different irrigation management methods in the NCP. The results from evaluation and validation analyses were compared to observed data from 8 field experiments, and the results indicated that the model can accurately predict these parameters. The modified CERES-Wheat model was then used to simulate the development and growth of winter wheat under different irrigation treatments ranging from rainfed to four irrigation applications(full irrigation) using historical weather data from crop seasons over 33 years(1981–2014). The data were classified into three types according to seasonal precipitation: 100 mm, 100–140 mm, and 140 mm. Our results showed that the grain and biomass yield, harvest index(HI) and WUE responses to irrigation management were influenced by precipitation among years, whereby yield increased with higher precipitation. Scenario simulation analysis also showed that two irrigation applications of 75 mm each at the jointing stage and anthesis stage(T3) resulted in the highest grain yield and WUE among the irrigation treatments. Meanwhile, productivity in this treatment remained stable through different precipitation levels among years. One irrigation at the jointing stage(T1) improved grain yield compared to the rainfed treatment and resulted in yield values near those of T3, especially when precipitation was higher. These results indicate that T3 is the most suitable irrigation strategy under variable precipitation regimes for stable yield of winter wheat with maximum water savings in the NCP. The application of one irrigation at the jointing stage may also serve as an alternative irrigation strategy for further reducing irrigation for sustainable water resources management in this area.     

Effect of low-nitrogen stress on photosynthesis and chlorophyll fluorescence characteristics of maize cultivars with different low-nitrogen tolerances

Nitrogen(N) is a critical element for plant growth and productivity that influences photosynthesis and chlorophyll fluorescence. We investigated the effect of low-N stress on leaf photosynthesis and chlorophyll fluorescence characteristics of maize cultivars with difference in tolerance to low N levels. The low-N tolerant cultivar ZH311 and low-N sensitive cultivar XY508 were used as the test materials. A field experiment(with three N levels: N0, 0 kg ha–1; N1, 150 kg ha–1; N2, 300 kg ha–1) in Jiyanyang, Sichuan Province, China, and a hydroponic experiment(with two N levels: CK, 4 mmol L–1; LN, 0.04 mmol L–1) in Chengdu, Sichuan Province, China were conducted. Low-N stress significantly decreased chlorophyll content and rapid light response curves of the maximum fluorescence under light(Fm′), fluorescence instable state(Fs), non-photochemical quenching(qN), the maximum efficiency of PSII photochemistry under dark-adaption(Fv/Fm), potential activity of PSII(Fv/Fo), and actual photochemical efficiency of PSII(ΦPSII) of leaves. Further, it increased the chlorophyll(Chl) a/Chl b values and so on. The light compensation point of ZH311 decreased, while that of XY508 increased. The degree of variation of these indices in low-N tolerant cultivars was lower than that in low-N sensitive cultivars, especially at the seedling stage. Maize could increase Chl a/Chl b, apparent quantum yield and light saturation point to adapt to N stress. Compared to low-N sensitive cultivars, low-N tolerant cultivars maintained a higher net photosynthetic rate and electron transport rate to maintain stronger PSII activity, which further promoted the ability to harvest and transfer light. This might be a photosynthetic mechanism by which low-N tolerant cultivar adapt to low-N stress.     

砂姜黑土小麦根系性状与冠层光合对不同灌水方式的响应

【目的】明确小麦前期不同灌水方式对中后期根系性状、冠层光合及产量影响的潜在机理,揭示小麦根系性状与冠层光合间的关系。【方法】在人工玻璃防雨蓬下,设置以下10种灌水处理CK（生育前期水分充足）、W1_20d （苗后20 d灌水50 mm）、W2_40d （苗后40 d灌水50 mm）、W3_60d （苗后60 d灌水50 mm）、W4_80d （苗后80 d灌水50 mm）、W5_100d （苗后100 d灌水50 mm）、W6_120d （苗后120 d灌水50 mm）、W7_20d+60d （苗后20 d灌水25 mm+苗后60 d灌水25 mm）、W8_40d+80d （苗后40 d灌水25 mm + 苗后80 d灌水25 mm）和W9_60d+100d（苗后60 d灌水25 mm + 苗后100 d灌水25 mm）。研究前期不同灌水方式对小麦中后期根系性状、冠层单叶面积、叶绿素密度、光合速率、光合有效辐射、叶绿素荧光参数和产量的影响。【结果】小麦生育前期适当延迟灌水日期有利于增加总根长、总表面积、总体积、平均直径、总根尖数和总分叉数,其中W5_100d与CK间的差异不显著,但两者显著高于W1_20d和W6_120d。CK孕穗期和开花期的倒1、倒2和倒3叶的单叶面积最大,但与W5_100d差异不显著,且总灌水量相同下灌水次数对冠层单叶面积的影响不显著。生育前期灌1水下冠层叶绿素密度随灌水日期的推迟呈先增加后下降的趋势,并以W5_100d最高,W1_20d最低。W5_100d孕穗期、开花期和灌浆中期的冠层光合速率显著高于CK,分别增加了7.5%、8.9% 和 8.9%,但冠层光合速率受灌水次数影响不明显。灌1水下,W5_100d孕穗期、开花期和灌浆中期的冠层光合有效辐射最高,分别比W1_20d和W6_120d显著增加了18.7%、9.7%、11.0% 和5.7%、4.9%、4.3%。W5_100d孕穗期和开花期的叶绿素荧光参数F_o、F_m、F_v/F_m、Φ_psII和ETR值最高,灌水次数对叶绿素荧光参数的影响不显著。W5_100d的产量和收获指数与CK差异不显著,两指标分别比W1_20d和W6_120d显著增加了15.4%、22.1% 和3.2%、9.2%。【结论】生育前期过早和过晚灌水对小麦中后期根系生长、冠层光能利用及产量形成不利,适当延长前期灌水日期可获得优于或相当于小麦生育前期水分充足处理的根系性状、冠层光合及产量,灌水次数在灌水量相同下的效果不明显。     

AquaCrop模型对旱区冬小麦抗旱灌溉的模拟研究

【目的】根据干旱情况及时采取灌溉措施,对旱区抗旱以及提高水分利用效率具有重要意义。从大田农业的实际情况出发,研究AquaCrop模型在旱区的适用性及干旱年份抗旱灌溉模拟,为实现抗旱保产提供依据。【方法】于2012-2014年,在旱区陕西杨凌及杨凌周边区域进行冬小麦大田试验,采用2013-2014年揉谷试验区的冬小麦观测数据进行模型的参数调试,采用2012-2013年揉谷试验区和2013-2014年武功试验区的冬小麦观测数据进行模型的验证,从而获得AquaCrop模型在陕西杨凌及周边地区的模型参数。模型参数包括影响冠层生长的冠层增长系数、冠层衰老系数和最大冠层覆盖度,影响生物量积累的水分生产力,影响产量形成的参考收获指数等。然后根据调查的干旱年份2012-2013年的灌溉情况制定出4种灌溉情景,并利用参数本地化后的AquaCrop模型模拟2012-2013年4种灌溉情景对冬小麦生物量和产量的影响,通过模拟结果得出最优灌溉策略。最后比较2012-2013年揉谷试验区、2013-2014年揉谷试验区和武功试验区冬小麦的产量水分利用效率。【结果】在冬小麦冠层覆盖度方面,AquaCrop模型模拟的冠层覆盖度和实测值之间的决定系数（R²）与均方根误差（RMSE）分别为0.464和8.0%。在冬小麦生物量模拟方面,AquaCrop模型模拟的生物量和实测值之间的R²和RMSE分别为0.889和1.622 t·hm^-2。在冬小麦产量模拟方面,AquaCrop模型模拟的产量与实测产量之间的RMSE为0.377 t·hm^-2。2013年为干旱年份,在播种后第77天进行冬灌并且在播种后第172天的拔节期再进行灌溉的两种情景获得最大的生物量;在播种后第77天进行冬灌、播种后第172天拔节期和播种后第200天抽穗期再分别灌溉,小麦产量最高,达到6.451 t·hm^-2。2012-2013年揉谷试验区、2013-2014年揉谷试验区和武功试验区冬小麦的产量水分利用效率分别为1.84、1.69和1.82 kg·m^-3。【结论】AquaCrop模型能够较好地模拟旱区冬小麦的生物量和产量,并且AquaCrop模型模拟的干旱年份下不同灌溉策略的生物量和产量,基本可以说明不同灌溉时间和灌溉次数对冬小麦最终产量的影响。同时说明2012-2013年增加的2次灌溉使干旱年份冬小麦的产量水分利用效率超过正常年份。以上研究符合当地农业生产实际情况,说明AquaCrop模型可以为旱区抗旱保产提供依据。AquaCrop模型具有很好的应用前景,正逐渐成为一个重要的田间决策工具。     

Canopy morphological changes and water use efficiency in winter wheat under different irrigation treatments

Water is a key limiting factor in agriculture. Water resource shortages have become a serious threat to global food security. The development of water-saving irrigation techniques based on crop requirements is an important strategy to resolve water scarcity in arid and semi-arid regions. In this study, field experiments with winter wheat were performed at Wuqiao Experiment Station, China Agricultural University in two growing seasons in 2013–2015 to help develop such techniques. Three irrigation treatments were tested: no-irrigation(i.e., no water applied after sowing), limited-irrigation(i.e., 60 mm of water applied at jointing), and sufficient-irrigation(i.e., a total of 180 mm of water applied with 60 mm at turning green, jointing and anthesis stages, respectively). Leaf area index(LAI), light transmittance(LT), leaf angle(LA), transpiration rate(Tr), specific leaf weight, water use efficiency(WUE), and grain yield of winter wheat were measured. The highest WUE of wheat in the irrigated treatments was found under limited-irrigation and grain yield was only reduced by a small amount in this treatment compared to the sufficient irrigation treatment. The LAI and LA of wheat plants was lower under limited irrigation than sufficient irrigation, but canopy LT was greater. Moreover, the specific leaf weight of winter wheat was significantly lower under sufficient than limited irrigation conditions, while the leaf Tr was significantly higher. Correlation analysis showed that the increased LAI was associated with an increase in the leaf Tr, but the specific leaf weight had the opposite relationship with transpiration. Optimum WUE occurred over a reasonable range in leaf Tr. In conclusion, reduced irrigation can optimize wheat canopies and regulate water consumption, with only small reductions in final yield, ultimately leading to higher wheat WUE and water saving in arid and semi-arid regions.     

Sublethal effects of sulfoxaflor on the fitness of two species of wheat aphids,Sitobion avenae(F.) and Rhopalosiphum padi(L.)

Sitobion avenae(F.) and Rhopalosiphum padi(L.) are two important pests of wheat in China. They typically coexist in fields during the late period of wheat growth. Sulfoxaflor is a novel sulfoximine insecticide that demonstrates broad-spectrum efficacy, especially in targeting sap-feeding insects. This study was carried out to investigate the sublethal effects of sulfoxaflor on the development, longevity, and reproduction of two species of wheat aphids. Our results showed that sublethal concentrations of sulfoxaflor did not cause significant effects on the fecundity or the longevity of the parent generation(F_0 generation) of either S. avenae or R. padi. However, it caused transgenerational sublethal effects. For S. avenae, adult longevity of F_1 generation was significantly decreased. No significant differences were observed on the population parameters of S. avenae in the F_1 generation. For R. padi, the adult preoviposition period(APOP) and the total preoviposition period(TPOP) of F_1 generation were significantly reduced. The mean generation time(T) was significantly reduced in the R. padi F_1 generation. What's more, the intrinsic rate of increase(r_m) and the finite rate of increase(λ) were significantly increased in the R. padi F_1 generation. Taken together, these results suggest that exposure to the LC_(25) of sulfoxafl had no effects on the parent generation of S. avenae or R. padi, but it reduced adult longevity of S. avenae as a negative effect and increased the r_m and λ of R. padi in the first progeny generation, which may have an impact on the population dynamics of R. padi.     

滴灌条件下水肥耦合对北疆冬小麦生理生长和产量的影响

[目的]研究滴灌下水肥耦合对北疆冬小麦生理生长与产量的影响,确定北疆滴灌冬小麦最佳水肥施用量.[方法]供试作物为当地主栽小麦品种新冬8号.采用2因素3水平设计,2因素为灌水量和施氮量,灌水量3个水平分别为2 700、3 600、4 500 m3/hm2,施氮量3个水平分别为150、450、750 kg/hm2;对照为常规畦灌处理,灌水4次,灌水量为3 600 m3/hm2,施肥量为450 kg/hm2.[结果]滴灌和畦灌条件下冬小麦株高变化趋势为返青分蘖期至抽穗期急剧增长,抽穗后株高增长相对缓慢;拔节期水分增加对小麦株高的影响较大;在相同灌水量的情况下,冬小麦株高随着施氮量的增加而增大;在相同施氮量的情况下,滴灌冬小麦株高随着灌水量的增加而增大.滴灌和畦灌条件下,冬小麦叶面积指数（LAI）在生育期内呈正态曲线变化,随着小麦生育期推进LAI呈先升后降的变化趋势,孕穗期LAI最高;在相同灌水量的情况下,随着施氮量的增加,LAI也增大;在相同施氮量的情况下,随着灌水量的增加,LAI随着增大;水肥耦合对小麦产量、穗数、千粒重和质量影响较大,但对穗粒数的影响不显著.[结论]该研究可为大面积推广冬小麦滴灌技术和制定合理的灌溉施肥管理措施提供科学依据.     

土壤水分与氮素追施比率的关系

在黄淮豫东平原商丘试验区进行了三年冬小麦土壤水分与Ｎ素追施比率的关系田间试验。结果表明，冬小麦的土壤水分和追Ｎ比率间存在明显的互作效应，不同土壤水分条件要求与之相适宜的追Ｎ比率。在旱作条件下（冬小麦生育期降雨２００～２６０ｍｍ），适宜的追Ｎ比率为２５％或０（全部底施）；中等以上供水条件（全生育期浇水二次以上）以５０％的追Ｎ比率为宜。只有如此才能提高水分利用效率和肥料利用率，充分发挥水肥的效益     

施氮和不同栽培模式对半湿润农田生态系统冬小麦群体特征的影响

探讨了不同施氮水平及不同栽培模式下小麦群体特征的动态变化,旨在为黄土高原旱地农业的合理施肥与栽培奠定基础。在黄土高原南部年降水量632 mm左右的半湿润区,以小偃22为供试品种,研究不同施氮水平(设不施氮和每公顷施纯氮120 kg)及不同栽培模式(常规栽培、地膜覆盖、垄沟栽培和垄播覆膜栽培)对小麦群体特征的影响。结果表明,施氮和栽培模式主要通过影响群体分蘖、叶面积和地上部生物量而影响小麦群体结构。施氮能够明显增加小麦群体的分蘖数,而垄播覆膜栽培模式有利于增加小麦单株分蘖数。随小麦生育期的推进,叶面积指数(LAI)先增后减;施氮处理LAI比不施氮处理显著增加20%(P<0.01);垄播覆膜栽培模式下LAI明显高于其他栽培模式。从开花期到成熟期,小麦冠层透光率(DIFN)依次上升,施氮对DIFN的影响不明显;地膜栽培和垄播覆膜栽培模式下的DIFN与其他栽培模式间均存在极显著差异(P<0.01);施氮与栽培模式对DIFN的交互作用达到极显著水平(P<0.01),以常规栽培、不施氮处理的DIFN最大。小麦地上部生物量在灌浆前持续增加,灌浆到收获期呈下降趋势;施氮能够极显著增加地上部生物量(P<0.01),不同栽培模式的小麦地上部生物量不同,覆膜处理明显高于不覆膜处理,垄播覆膜比地膜栽培更有利于增加小麦地上部生物量,进而提高小麦籽粒产量。综上认为,施氮有助于提高冬小麦叶面积指数等生理指标;就小麦群体特征而言,地膜覆盖和垄播覆膜栽培应为首选栽培模式。     

Identification of the resistance gene to powdery mildew in Chinese wheat landrace Baiyouyantiao

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most damaging diseases to wheat in the world. The cultivation of resistant varieties of wheat is essential for controlling the powdery mildew epidemic. Wheat landraces are important resources of resistance to many diseases. Mapping powdery mildew resistance genes from wheat landraces will promote the development of new varieties with disease resistance. The Chinese wheat landrace Baiyouyantiao possesses characteristic of disease resistance to powdery mildew. To identify the resistance gene in this landrace, Baiyouyantiao was crossed with the susceptible cultivar Jingshuang 16 and seedlings of parents and F₁, BC₁, F₂, and F_2:3 were tested with Bgt isolate E09. The genetic results showed that the resistance of Baiyouyantiao to E09 was controlled by a single recessive gene, tentatively designated PmBYYT. An Illumina wheat 90K single-nucleotide polymorphism (SNP) array was applied to screen polymorphisms between F₂-resistant and F₂-susceptible DNA bulks for identifying the chromosomal location of PmBYYT. A high percentage of polymorphic SNPs between the resistant and susceptible DNA bulks was found on chromosome 7B, indicating that PmBYYT may be located on this chromosome. A genetic linkage map of PmBYYT consisting of two simple sequence repeat markers and eight SNP markers was developed. The two flanking markers were SNP markers W7BL-8 and W7BL-15, with genetic distances of 3 and 2.9 cM, respectively. The results of this study demonstrated the rapid characterization of a wheat disease resistance gene and SNP marker development using the 90K SNP assay. The flanking markers of gene PmBYYT will benefit marker-assisted selection (MAS) and map-based cloning in breeding wheat cultivars with powdery mildew resistance.     

滴灌与沟灌对杨树细根空间分布的影响

  目的  探究不同灌溉方式对杨树Populus细根生长和分布的影响,为滴灌培育人工林提供理论和技术依据。  方法  以5年生欧美杨107 Populus × euramericana ‘Neva’为研究对象,在滴灌和沟灌栽培的人工林中选取标准木,分别在株间、对角和行间方向距树干20、50、100和150 cm处采用根钻法取样,比较其细根生物量密度、细根根长密度、细根比根长的差异。  结果  滴灌条件下株间方向的细根生物量密度与沟灌的差异随水平距离增加而增大(P＜0.05),对角和行间方向随水平距离增加其差异减小。滴灌下细根生物量密度在株间方向距树干50 cm处最大,对角和行间方向在距树干20 cm处最大。滴灌下株间方向的细根根长密度与沟灌的差异随水平距离增加而增大(P＜0.05),对角和行间方向的差异随水平距离增加而减小。滴灌下细根根长密度在株间方向距树干50 cm处最大,对角和行间方向在距树干20 cm处最大。滴灌和沟灌下0~40 cm土层的细根生物量分别占0~60 cm土层的81%和73%,细根根长分别占0~60 cm土层的85%和80%。滴灌和沟灌下的比根长随水平距离增加而增大,且均表现为沟灌大于滴灌,不同方向比根长的差异在距树干20 cm处最大,在距树干50 cm处最小。  结论  滴灌能促进杨树人工林细根的生长和周转,影响细根的空间分布,提高林地生产力。图4表1参28     

滴灌施肥水肥耦合对温室番茄产量、品质和水氮利用的影响

【目的】水肥是限制作物增产的两大因子,不合理的灌溉与施氮不仅难于增加产量,还会增加土壤剖面硝态氮累积、降低作物品质及水氮利用效率。针对西北半干旱地区温室蔬菜灌水和施肥存在的问题,通过滴灌施肥水肥耦合对温室番茄产量品质和水氮利用的影响,研究滴灌施肥条件下温室番茄高产优质高效的灌水施肥制度。【方法】通过温室番茄小区试验,设常规沟灌施肥（100%ET₀,N240-P₂O₅120-K₂O150 kg·hm^-2）以及3个滴灌水量（高水W₁：100%ET₀、中水W₂：75%ET₀、低水W₃：50%ET₀）和3个施肥水平（高肥F₁：N240-P₂O₅120-K₂O150 kg·hm^-2、中肥F₂：N180-P₂O₅90-K₂O112.5 kg·hm^-2、低肥F₃：N120-P₂O₅60-K₂O75 kg·hm^-2）,共10个处理,分析番茄生长产量、品质、土壤硝态氮分布以及水氮吸收利用对不同灌水量和施肥量的响应规律。【结果】与常规沟灌施肥相比,滴灌施肥增加番茄产量31.04 t·hm^-2、干物质量3 208 kg·hm^-2和总氮吸收量73.13 kg·hm^-2,增幅分别为46.9%、54.0%和82.4%,同时增加果实中维生素C（Vc）含量61.8%;降低土壤中硝态氮含量;水分利用效率（WUE）和氮肥利用率（NUE）分别增加46.4%和76.5%。滴灌施肥条件下,W₁F₂处理总干物质量最大（9 248 kg·hm^-2）,产量和植株氮素吸收量均与灌水量和施肥量正相关,增加施肥量带来的增产效应大于灌水,且W₁F₂处理产量和氮素吸收量增加幅度最大。增加灌水量,降低施肥量,WUE逐渐下降,NUE逐渐上升,W₃F₁处理WUE最大（47.7 kg·m^-3）,W₁F₃处理NUE最大（65.6%）,且W₃F₂处理的WUE和W₁F₂处理的NUE增加幅度明显大于其他处理。土壤中硝态氮含量受灌水、施肥以及水肥交互效应影响显著,随灌水量的增加呈先增大后降低的趋势,随施肥量的增加逐渐增大,在滴头正下方没有明显累积,在湿润土体的横向边缘产生累积,W₁F₂处理土壤中硝态氮含量较小,分布更均匀。增大灌水量显著降低番茄Vc、番茄红素和可溶性糖含量以及营养累积量;增大施肥量,品质含量以及营养累积量呈先增大后降低的趋势;W₃F₂处理获得最大的Vc和番茄红素含量及营养累积量,最大的可溶性糖含量及较大的营养累积量。【结论】温室番茄滴灌施肥技术能够达到高产优质和高效的目的,当追求产量和氮肥利用率时,高水中肥（W₁F₂：100%ET₀,N180-P₂O₅90-K₂O112.5 kg·hm^-2）处理能获得较高的产量和NUE以及较低的土壤硝态氮含量;当追求品质和水分利用效率时,低水中肥（W₃F₂：50%ET₀,N180-P₂O₅90-K₂O112.5 kg·hm^-2）处理获得最大的维生素C、可溶性糖和番茄红素含量以及较高的水分利用效率。     

不同水分处理对滴灌春小麦水分利用效率及产量的影响

研究不同水分处理对春小麦滴灌水分在土壤中的分布状况、水分利用效率（WUE）及产量的影响。结果表明,不同水分处理对滴灌小麦土壤水分的分布有很大影响,同一土层0～20cm土壤含水率在灌溉前后具有明显的变化;0～40cm土层土壤含水率整体趋于平缓,总体表现为W1处理（150mm）〈W2处理（300mm）〈W3处理（450mm）〈W4处理（600mm）;40～60cm土层距离滴灌带不同远近的土壤含水率变化不明显。W3处理的WUE最高,漫灌的WUE最低。滴灌小麦和漫灌小麦不同水分处理的产量间差异达显著水平,同一水分处理不同行之间由于灌溉量的不同也表现差异性;两品种产量均随灌水增加而增加,灌水过多而降低的趋势。     

Physiological evaluation of nitrogen use efficiency of different apple cultivars under various nitrogen and water supply conditions

Nitrogen(N) deficiency is a common problem for apple(Malus×domestica) production in arid regions of China. However, N utilization efficiency(NUE) of different apple cultivars grown under low N conditions in arid regions has not been evaluated. In this study, NUE was assessed for one-year-old seedlings of six apple cultivars, Golden Delicious, Qinguan, Jonagold, Honeycrisp, Fuji and Pink Lady, grafted onto Malus hupehensis Rehd. rootstocks. Four treatments were used, including control water with control N(CWCN), limited water with control N(LWCN), control water with low N(CWLN) and limited water with low N(LWLN). Our results showed that growth indices such as biomass, plant height and stem diameter, and photosynthetic rate of all cultivars decreased in the order CWCNCWLNLWCNLWLN. When subjected to LWLN treatment, Qinguan showed better growth and photosynthetic characters than other tested cultivars. Additionally, Qinguan and Pink Lady had higher NUE, while Honeycrisp and Jonagold had lower NUE, based on the determination of biomass, photosynthetic parameters, chlorophyll content, the maximal photochemical efficiency of PSII(F_v/F_m), ~(15) N and N contents.     

黄土塬区冬小麦产量及水分利用效率对播前底墒变化与生育期差别供水的响应

【目的】通过黄土塬区播前底墒变化和生育期差别供水(降水+补充灌溉)对冬小麦产量、耗水量以及水分利用效率影响的田间试验,揭示该区域农田有限水资源高效利用的调控机制,明确现有措施下冬小麦旱作生产潜力可实现水平。【方法】划设田间试验小区,在夏闲期通过覆盖保水与生物耗水措施形成底墒差异的基础上,设计如下试验:(1)由不同底墒+生育期降水形成4个冬小麦全生育期无补灌处理,以分析冬小麦产量及水分利用效率对播前底墒变化的响应。其2 m土层底墒变化范围为350—550 mm。(2)相同底墒下不同生育期灌一水处理:在平均底墒约为500 mm下分别在拔节期、孕穗期和灌浆期补充灌溉40 mm,探讨冬小麦不同生育期对等量灌溉的响应差别。(3)高底墒542.3 mm与571.6 mm下分别进行灌2水与4水处理,形成冬小麦全生育期比较充分的供水条件,研究冬小麦在低水分胁迫下产量提升的可能程度及其水分利用效率特征。【结果】(1)在黄土塬区降水季节分布特征下,播前底墒对冬小麦产量具有决定性作用,产量随底墒线性增加。在做好夏闲期蓄水保墒的基础上,旱作冬小麦产量可达到充分供水情况下能够取得产量的88%—90%水平。(2)与2 m土层底墒为500 mm且生育期无补充灌溉的处理比较,供水增加同为40 mm时,表现为底墒增加处理的产量提高了11.8%,次之是在拔节期与孕穗期分别补灌的处理,但三者间产量无显著差异;播前底墒较高并在拔节期及孕穗期补充灌溉的处理冬小麦产量达到试验年份较高水平,且作物水分利用效率(WUE)也得到提高。(3)冬小麦产量与耗水量表现为Logistic曲线关系,随着耗水量的增大,产量提升速率表现为先快后慢,边际水分利用效率(MWUE)则持续降低,而WUE表现为上升、达到峰值和下降三个阶段,且WUE到达其最高值的耗水量小于产量到达其最高值的耗水量。【结论】黄土塬区气候条件下,播前底墒差别与生育期差别供水对冬小麦产量均有影响,由底墒或不同生育时期分别增加等量供水在总供水水平相同时其增产效应基本一致;采用Logistic曲线模型可以较好地模拟冬小麦产量与耗水量之间的关系,揭示产量、耗水量及WUE间的内在联系。