Urban green spaces serve as critical but highly heterogeneous components of carbon (C) sinks in urban ecosystems, yet substantial uncertainty persists regarding soil organic carbon (SOC) sequestration and stabilization across different species. This study examined the effects of four common turfgrass species (zoysia grass, bluegrass, tall fescue, and bentgrass) on SOC pool distribution and stability in surface (0–10 cm) and subsurface (10–20 cm) soil following eight years of cultivation. Soil organic matter was fractionated into particulate organic matter (POM) and mineral-associated organic matter (MAOM), with chemical composition analyzed via solid-state 13C-NMR. All species increased SOC content, though the magnitude of enhancement varied 2.4-fold. Zoysia and tall fescue achieved the highest gains, significantly outperforming bentgrass. While MAOM fractions were all significantly elevated, only zoysia grass enriched both POM and MAOM, with its recalcitrant alkyl-C compounds enhancing chemical stability. Soil under tall fescue exhibited higher microbial biomass carbon content, along with significantly greater surface soil respiration compared to the control. These differences in microbial activity and carbon pool distribution drove SOC stabilization and decomposition. For urban carbon management, we recommend prioritizing zoysia grass for long-term carbon stabilization and tall fescue for maximizing total carbon stocks, while noting that management-sensitive species like bentgrass may provide unreliable C-sink functions.

为研究植丝式混合草坪中人造草丝对草坪草生长及养分去向的影响,本研究以高羊茅(Festuca arundinacea)品种'交战Ⅳ'为试验材料,以不植丝处理为对照,研究植丝对草坪坪观质量、生长速度和生物量、草坪草养分吸收、草坪土壤中养分残留以及养分淋溶损失的影响.结果表明:植丝促进了草坪草的生长并提升了草坪的坪观质量.植丝后草坪草氮素和磷素吸收量增加,其中草屑和根系氮素的吸收量最高分别增加了30.0％和40.6％,草屑磷素吸收量最高增加了24.8％.土壤中矿质氮和速效磷残留量增加,分别最高增加了33.9％和87.0％.硝态氮淋溶损失量减少,最大降幅可达79.3％.因此,植丝促进了草坪草生长,提高了草坪草氮素和磷素利用效率,降低了草坪氮素淋溶风险.

Aims: Increases in nitrogen (N) deposition may significantly affect the organic carbon (OC) cycle in soil. The inconsis-tent findings of the influence of added N on soil OC pools highlight the need of quantifying responses of the OC pool distribution to N addition. Moreover, the influence of N addition with a mixture of organic and inorganic N on OC pool distribution and stabilization in grassland soil remains unclear.Methods: We carried out a five-year field experiment with adding N to examine the effects of different types of N addi-tion on soil OC pool distribution and transformation in a meadow steppe in Inner Mongolia. We applied N in the ratios of inorganic N (IN) and organic N (ON) at 10:0 (N1), 7:3 (N2), 5:5 (N3), 3:7 (N4), 0:10 (N5), and 0:0 (CK), respectively. We measured OC content in bulk soil, particulate organic matter (POM), and mineral-associated organic matter (MAOM) fractions. Additionally, a short-term soil incubation was conducted to assess potential OC mineralization.Results: Our study showed no significant effect on soil organic carbon content of different ratios of IN/ON addition. N addition reduced microbial biomass C/N ratio, the fraction of mineral-associated organic matter, cumulative CO2 emission, and microbial metabolic quotient. Compared with ON addition alone, IN addition alone showed a stronger effect on the C in different soil fractions and soil OC mineralization. The particulate organic matter (POM) fraction was more sensitive to N addition than the mineral-associated organic matter (MAOM) fraction.Conclusions: Our results suggest that the contribution of N in organic and inorganic forms affecting OC pool distribution with different turnover rates should be considered when assessing the effects of N addition types on soil OC processes in grassland.

由无机氮和有机氮沉降共同构成的大气氮沉降已成为全球变化的重要现象之一,影响着草原土壤磷循环过程.以内蒙古额尔古纳草甸草原为研究对象,进行了 5年不同形式氮添加试验,设置的无机氮和有机氮比例分别为10∶0(N1)、7∶3(N2)、5∶5(N3)、3∶7(N4)、0∶10(N5)和对照处理0∶0(CK).通过测定土壤有效磷含量、全磷含量及酸性磷酸酶活性,结合生态化学计量学来探究不同形式氮添加对草甸草原不同土层磷素含量和碳氮磷化学计量特征的影响.结果表明,不同形式氮添加对土壤全磷含量和酸性磷酸酶活性无显著影响(P＞0.05);0-10cm表层土壤有效磷含量在N2处理下显著高于对照和其他氮添加处理(P＜0.05).土壤碳氮比(C/N)、碳磷比(C/P)、氮磷比(N/P)均不受氮添加形式的影响;0-10 cm表层土壤C/N、C/P、N/P均值低于全国平均水平.因此,有必要在更长的时间尺度上继续跟进不同形式氮添加对草原土壤磷循环的影响.

The effects of different reinforcement materials on the quality of the turf and the performance of the turf-bed in the mobile sports field was investigated. The ‘Titanium 2LS’ variety of Festuca arundinacea was used as the test material, and the mobile sports field turf without reinforcement material was used as control. The performance of turf-bed and quality of movement was investigated by simulating medium intensity trampling with a tramper so as to study the effects of curing agents and plant fibers on the quality of mobile sports turf. The results showed that 2 weeks before trampling, XW treatment significantly improved the color, normalized vegetation index, and turf quality evaluation parameters (P < 0.05). There was no significant difference between results for the quality evaluation analysis of Jipingguan and CK (P > 0.05). WOH treatment could effectively maintain soil compaction, YP significantly improved surface hardness and torsional friction of turf, whereas YP treatment significantly increased the risk of head injury in players (P < 0.05). After 4 weeks of trampling, the structure of the turf-bed was disturbed by trampling, and the reinforcement performance of each reinforcement material treatment decreased significantly (P < 0.05). To summarize, under moderate trampling intensity, the use of WOH in the reinforcement material in the turf-bed of the mobile stadium can effectively ensure the stable structure of the turf-bed to reduce the risk of player injury and meet the quality requirements of high-quality stadiums.

为研究地温调控对高温胁迫下草坪养分动态变化的影响,本研究以匍匐翦股颖(Agrostis stolonifera)为试验材料,以正常生长环境为对照,地下 20 cm处控温 27、24、21℃为处理,研究地温调控对草坪草养分吸收、草坪土壤养分动态以及土壤微生物和酶活性的影响.结果表明:降温促进了匍匐翦股颖生长,并增加了草坪草生物量,草坪草氮素和磷素吸收量显著增加,并且在 21℃处理时效果最好,地上、地下生物量分别比对照增加了 44.3%和220.7%,地下部的氮素、磷素吸收量分别增加了147.9%和179.3%.土壤中矿质氮含量降低,在24℃处理下10-20 cm土层最高降低了 48.5%.土壤速效磷含量增加,在 21℃处理下 0-10 cm土层最高,增加了 82.5%.土壤微生物量碳含量随着降温幅度的增加,呈现先上升后下降的趋势,而 10-20 cm土层的微生物量氮含量则呈现上升的趋势,土壤碳、氮、磷循环相关酶活性普遍受到降温处理影响.综上,夏季地温调控促进了匍匐翦股颖生长以及草坪草对土壤养分的吸收,影响了土壤碳、氮、磷循环相关酶活性,改变相应养分的有效性.此外,建议夏季运动场降温后适量补充氮肥.

新农科建设对草业科学等涉农专业的教学改革提出了新要求.草产品加工学是草业科学专业的核心课程,注重理论与实践的有机结合.但传统教学模式以教师讲授为主,学生参与度不高.BOPPPS模式是一种基于体验式学习理论而设计的教学模型,其重要特点在于教学互动.在新农科背景下为培养高素质复合型草业科学专业人才,笔者将BOPPPS教学模式引入草产品加工学课程教学中,调整教学学时、重新编写教案、改革考核方式,构建了本课程的BOPPPS教学体系.在BOPPPS模块设计过程中,笔者综合运用参与式教学、小组讨论、小型测验、案例分析、课堂辩论等多种教学方法,并将网络教学平台作为部分学生自学章节的辅助工具.实践表明,BOPPPS教学模式的运用,激发了学生的学习兴趣,调动了学生的主观能动性,培养了学生扎实的理论基础,提高了学生的创新能力,显著提升了教学质量.本教学设计与实践也为国内高校开展草产品加工学教学研究提供有益参考.

氮沉降增加已成为全球变化的重要现象之一,已显著影响草地土壤氮素循环.以内蒙古额尔古纳草甸草原为研究对象,进行了6年不同形式氮添加试验,设置无机氮和有机氮比例分别为:10:0(N 1),7:3(N 2),5:5(N 3),3:7(N4),0:10(N5)和对照处理0:0(CK).通过土壤有机质物理分组及室内矿化培养的方法,从氮素形态、氮素组分及氮素潜在矿化三方面研究不同比例有机、无机氮添加对草原土壤氮素分配和转化特征的影响.结果表明,土壤全氮含量未受氮素添加形式的影响;氮添加显著提高了0～20 cm土层矿质氮含量,尤其是土壤硝态氮,其中N4(无机氮:有机氮=3:7)混合氮肥处理下硝态氮含量增幅最大,较对照处理增加1332％.不同形式氮添加没有影响氮素在土壤颗粒态有机氮(轻组)及矿物结合态有机氮(重组)中的占比;N1(无机氮:有机氮=10:0)处理显著提高了0～10 cm土层颗粒态有机氮(轻组)及0～20 cm土层矿物结合态有机氮(重组)中的氮素相对含量,较对照分别增加了91％和44％.氮添加增加了10～20 cm次表层土壤硝化速率的同时降低了氨化速率,但土壤净氮矿化速率不受氮添加形式的影响.因此,有机/无机氮添加比例变化对草原土壤氮素形态和周转的影响也更加复杂.

可溶性有机碳(Dissolved organic carbon,DOC)是陆地生态系统碳循环的关键物质,为研究公路对沿线土壤DOC的影响,本试验以距G109格尔木至拉萨段公路不同水平距离(20 m,100 m,400 m)土壤为研究对象,测定土壤DOC含量,结合紫外可见光谱和三维荧光光谱分析土壤可溶性有机质(Dissolved organic matter,DOM)的光谱特征.结果表明:在同一海拔高度下,公路显著影响了土壤DOC分布的空间格局,距公路不同距离土壤DOC含量由高到低依次为:400 m>100 m>20 m;公路影响了土壤的芳香化程度和疏水性组分,距离公路越近,土壤有机质越不稳定;结合荧光特征指数得出,土壤DOM主要属于微生物源输入,且腐殖化程度较低.因此,对公路周边环境进行生态修复时,要特别注意距离公路较近处,可以通过提高植被覆盖度的方式,增加土壤碳储量及稳定性,保护生态环境.

为研究地温调控对草坪高温胁迫的缓解作用,在地下20?cm处设置3个地温调控处理,调控温度分别保持在27、24和21?℃,以正常生长环境下的匍匐剪股颖(Agrostis stolonifera)草坪为对照(CK),探讨地温调控对草坪土壤温度、草坪质量和根系生长的影响.结果表明:在高温季节,地温调控可以显著降低土壤温度(P?<?0.05),缓解高温胁迫下草坪质量和生长情况下降的趋势,调控温度在24?℃以下效果较明显,调控温度为21?℃效果最好;在21?℃调控处理下,5和20?cm土层土壤温度分别较CK处理降低了2～4.5和5～7?℃,草坪色泽和归一化差异植被指数(NDVI)分别提高了17.8％和28.2％,地下生物量增加了58.2％,总根长、根表面积、根体积增加幅度最大可达84.5％、97.8％和112.7％,根系活力最高增加了46.9％.因此,地温调控处理可以有效缓解高温胁迫下剪股颖草坪生长下降的趋势,可以作为剪股颖草坪植物应对高温胁迫的有效措施,以21～24?℃为适宜调控温度.

为研究践踏对草垫式混合草坪草质量和根系生长的影响,本研究以多年生黑麦草品种'名仕'为研究材料,以无草垫处理为对照,通过践踏器模拟研究轻度、中度和重度践踏条件,进行为期4周的践踏处理,以此研究两种草垫对不同人造-天然混合草坪的坪观质量、生长特性和运动质量的影响.结果表明:在践踏条件下,草垫式混合草坪的色泽、盖度和坪观质量等综合表现优于天然草坪,且践踏强度越大差异越明显,其中在践踏4周后的重度践踏条件下,两个草垫试验组分别比对照组的色泽提高了45.5％和39.0％,盖度分别比对照组提高了136.4％和150.0％.在践踏处理下,草垫减缓了草坪的损伤程度,对草坪草地上和地下部分的生长起到了保护作用,对践踏具有缓冲作用,践踏4周后无背衬试验组的根长在轻度、中度和重度践踏下分别比对照组提高了105.3％、239.1％和152.6％.草垫在践踏胁迫下对草坪草生长起到了较为明显的保护作用,增加草坪的扭动摩擦,降低了摔倒的风险,但草垫增加了草坪的表面硬度和坪床紧实度,使得头部损伤风险加大,其中有背衬结构的风险较大.因此在草垫式混合草坪的使用中要采取适宜的养护措施,避免硬度过高带来风险.

Perennial ryegrass (Lolium perenne ‘Neruda 1 BT’) and tall fescue (Festuca arundinacea ‘Crown’) were used to study the effect of the carpet on turfgrass quality and root growth. Pot experiments with a no-carpet control were carried out to study the effects of carpet on turf performance quality, aboveground and underground biomass, and root morphological parameters under different seeding conditions (perennial ryegrass, tall fescue, and their mixture). The carpet significantly decreased turfgrass performance traits such as color. Turfgrass color was significantly lower than that of the control for perennial ryegrass, tall fescue, and their mixture by 3.8%, 5.3% and 3.9%, respectively. At the same time, the carpet decreased the aboveground biomass of perennial ryegrass and tall fescue by 11.8% and 16.9%, respectively. Additionally, as for the root morphological parameters of the root under the carpet, the total root length, root surface area, and root volume were all lower than those in the control to different degrees under different seeding conditions. Therefore, in artificial-natural hybrid turf, the carpet inhibited root growth under the carpet and further affected the growth of aboveground turf grass.

为研究人造草垫式混合草坪中不同的人造草垫对草坪表观质量和稳定性的影响,以多年生黑麦草品种"名仕"为研究材料,以无草垫处理为对照,研究了3种人造草垫植入对草坪表观质量、地上地下生物量和根系参数(根长、根表面积、根体积和根活力)的影响,并通过直剪试验对坪床稳定性进行测定.结果表明:各草垫处理均降低了草坪的色泽、归一化差异植被指数和密度,生长至116 d时,3个草垫处理组的密度分别比对照组降低了20.8％、8.7％和14.7％,有背衬的草垫结构增加了草坪草的均一度;同时,草垫处理降低了草坪草的地下生物量、根系长度、根总表面积和根系总体积,影响了垫上和垫下部分的根系活力.草垫处理增加了混合系统的抗剪强度和表面硬度,3个草垫处理组分别比对照组的内聚力增加了51.9％、162.7％ 和134.6％,硬度分别比对照组增加了34.6％、32.8％和45.8％.因此,人造草垫式混合草坪中,各种草垫在不同程度上抑制了根系生长,进而影响地上部分的生长和表观质量;人造草垫式混合系统稳定性高于天然草坪,且有背衬结构的草垫对提高坪床稳定性的效果更为明显,草垫对提高草坪的强度有积极作用.

Cover crops (CC) have been widely used to improve soil quality and sustain agricultural productivity. However, the turnover of carbon (C) and nitrogen (N) from different species and parts of CCs incorporated into the soil under Northern European conditions remains unclear. In this study, we examined mineralization of C and N from isolated shoots and roots of two leguminous and two non-leguminous CCs labeled with 15N tracers in a 100-day incubation experiment at 10 °C. After 100 days incubation, the average net N mineralization was 33% from the leguminous CCs and 20% from the non-legumes. Net N mineralization from shoots was 1–15% (% of the N input) higher than that from the corresponding roots, and the net C mineralization accounted for 53–62% and 18–39% of the total C applied with CC shoots and roots, respectively. The C/N ratio of plant residues was a good predictor for net N mineralization, while the lignin concentration was a good predictor for C mineralization from both roots and shoots. Roots of both legume and non-legume CCs caused net immobilization of (unlabeled) soil N, whereas no significant soil N immobilization occurred from shoots with low C/N ratios. Our results indicate that different CC characteristics (C/N ratio and lignin) control the turnover of residue N and C, respectively, in the soil. Our results further showed very limited interactions with soil N turnover (no priming effects) when materials with low C/N ratios were applied to soil.

Nitrogen (N) flows in organic cropping systems differ considerably from those in conventional systems. The difference is particularly due to the N in organic materials in organic systems as opposed to the mineral N in fertilizer in conventional systems, which differently affect crop N supply and N losses. This implies different responses of conventional and organic cropping systems to N inputs and N management. Therefore, N flow dynamics were studied in a range of arable cropping systems with 4-year crop rotations at three different sites in Denmark varying in soil (coarse sand, loamy sand and sandy loam) and climatic conditions. The long-term field experiments included an incomplete factorial combination of (1) rotations with grass-clover in organic farming (OGC) or grain legumes in organic farming (OGL) or conventionally managed (CGL) systems, (2) with (+CC) and without (-CC) cover crops, and (3) with (+M) and without (-M) animal manure (in OGC and OGL), and with (+F) mineral fertilizer (in CGL). Cover crops in OGC and OGL included a mixture of perennial ryegrass and clover (at the sites with coarse sand and sandy loam soils) or winter rye, fodder radish and vetch (at the site with loamy sand soil), and cover crops in CGL included only perennial ryegrass at all the sites. Higher N input and N output was observed in CGL compared to OGC and OGL. The differences in annual N output in cash crops between CGL and OGL, and CGL and OGC after accounting for effects of differences in N inputs were 15 and 27 kg N ha(-1), respectively. The N output was related to N input, with a higher response to mineral N in both fertilizer and manure than to biological N fixation (BNF). The N surplus (difference between N input and N output) was significantly lower in OGL/-M + CC compared with other treatments. The recycled N in above-ground plant residues was highest in OGC/-M + CC where grass-clover cuttings were left in the field, followed by + CC treatments in OGL and CGL. The response of nitrate-N leaching to N input depended on soil type and precipitation, and leaching was reduced by the use of cover crops. The nitrate-N leaching increased with increasing N input at rates of 0.13-0.22 kg N kg(-1) N input, and it increased with increasing N surplus at rates of 0.21-0.27 kg N kg(-1) N surplus.

Biological nitrogen (N) fixation (BNF) by legumes in organic cropping systems has been perceived as a strategy to substitute N import from conventional sources. However, the N contribution by legumes varies considerably depending on legumes species, as well as local soil and climatic conditions. There is a lack of knowledge on whether the N contribution of legumes estimated using short-term experiments reflects the long-term effects in organic systems varying in fertility building measures. There is also limited information on how fertilizer management practices in organic crop rotations affect BNF of legumes. Therefore, this study aimed to estimate BNF in long-term experiments with a range of organic and conventional arable crop rotations at three sites in Denmark varying in climate and soils (coarse sand, loamy sand and sandy loam) and to identify possible causes of differences in the amount of BNF. The experiment included 4-year crop rotations with three treatment factors in a factorial design: (i) rotations, i.e. organic with a year of grass-clover (OGC), organic with a year of grain legumes (OGL), and conventional with a year of grain legumes (CGL), (ii) with ( + CC) and without (- CC) cover crops, and (iii) with ( + M) and without (- M) animal manure in OGC and OGL, and with ( +F) mineral fertilizer in CGL. Cover crops consisted of a mixture of perennial ryegrass and clover (at the sites with coarse sand and sandy loam soils) or winter rye, fodder radish and vetch (at the site with loamy sand soil) in OGC and OGL, and only perennial ryegrass in CGL at all sites. The BNF was measured using the N difference method. The proportion of N derived from the atmosphere (%Ndfa) in aboveground biomass of clover grown for an entire year in a mixture with perennial ryegrass and harvested three times during the growing season in OGC was close to 100% at all three sites. The Ndfa of grain legumes in both OGL and CGL rotations ranged between 61% and 95% depending on location with mostly no significant difference in Ndfa between treatments. Cover crops had more than 92% Ndfa at all sites. The total BNF per rotation cycle was higher in OGC than in OGL and CGL, mostly irrespective of manure/fertilizer or cover crop treatments. There was no significant difference in total BNF between OGL and CGL rotations, but large differences were observed between sites. The lowest cumulated BNF by all the legume species over the 4-year rotation cycle was obtained at the location with sandy loam soil, i.e. 224-244, 96-128, and 144-156 kg N ha(-1) in OGC, OGL and CGL, respectively, whereas it was higher at the locations with coarse sand and loamy sand soil, i.e. 320-376, 168-264, and 200-220 kg N ha(-1) in OGC, OGL and CGL, respectively. The study shows that legumes in organic crop rotations can maintain N-2 fixation without being significantly affected by long-term fertilizer regimes or fertility building measures.

Zinc (Zn) biofortification of staple food crops is essential for addressing worldwide human malnutrition problem, but its success has been restricted by low soil Zn availability. With ethylenediaminetetraacetic acid (EDTA) addition, soil Zn availability is able to be increased in contaminated soils, but whether and how it will behave in uncontaminated calcareous soil with low available Zn, and its effect on winter wheat grain Zn need further research. In a series of pot experiments, winter wheat was grown on a low-Zn calcareous soil, with EDTA applied at different stages or in different rates, and then soil pH, soil available Zn, Zn fractions, and Zn concentration of different wheat organs were determined. Obtained results showed that grain Zn concentration was increased by 8%-46%, but grain yield was not affected by EDTA addition. With EDTA applied at sowing, straw Zn uptake was increased by 69%-120% during heading to filling, and after anthesis it significantly decreased and contributed 61% of the grain Zn uptake. Meanwhile, soil available Zn (DTPA-Zn) in rhizosphere and nonrhizosphere was increased by 185%-377%. Correspondingly, soil exchangeable Zn (Ex-Zn) was dramatically increased; Zn weakly bounded with organic matter (Wbo-Zn) and Zn bounded with carbonate (Carb-Zn) were increased by 4%-54% and 2-18 fold respectively; while Zn bounded with amorphous iron oxide (AmoFe-Zn), Zn bounded with crystal iron oxide (CryFe-Zn), and Zn in residue mineral (Res-Zn) were decreased by 78%, 10%-31%, and 6% respectively, and soil pH kept stable or increased by 0.1-0.2 unit. Among Zn fractions only Ex-Zn, Wbo-Zn, and Carb-Zn were significantly and positively correlated with DTPA-Zn. With EDTA application, the enhanced soil Zn transformation from unavailable Zn fractions (AmoFe, Cry-Fe, and Res) to available Zn fractions (Ex, Wbo, Carb), and the enhanced straw Zn uptake at anthesis and its remobilization to grain during filling period was responsible for the increase of grain Zn concentration. Also, without decreasing soil pH the unavailable soil Zn fractions can be still transformed to available Zn in calcareous soil.

【目的】通过取样调查和田间叶喷硒肥试验,研究中国不同麦区小麦籽粒硒含量状况、硒含量的影响因素以及提高硒含量的农艺措施。【方法】分别于2008—2009、2009—2010、2010—2011年小麦季收集中国不同麦区73份春小麦和582份冬小麦共计655份田间小麦样品,调查籽粒产量并测定籽粒硒含量。于2010—2011年在14个省（市）的30个国家小麦产业技术体系综合试验站开展叶面喷施硒肥试验,设叶面喷施清水或0.017%亚硒酸钠2个处理,于拔节中、末期各喷施1次,完全随机区组设计,重复3次,测定拔节前植株样品的硒含量和收获后籽粒产量和硒含量。【结果】655份小麦籽粒样品平均硒含量为64.6μg·kg -1 ,远不能满足以小麦为主食人群对硒的营养需求,变幅为0—821.0μg·kg -1 ,春、冬小麦平均分别为67.5和64.2μg·kg -1 。有63%缺硒,19%偏低,仅有8%富硒,未发现有小麦籽粒硒含量达到中毒水平。小麦籽粒硒含量在不同区域表现为北部高于南部、西部高于东部。各地的田间试验表明,叶面喷施亚硒酸钠对小麦籽粒产量没有显著影响,不喷硒和喷硒平均产量分别为6 650和6 649 kg·hm-2。叶喷硒肥使籽粒硒含量显著提高,不喷硒时,籽粒硒含量平均为31.0μg·kg -1 ,喷硒116 g·hm-2使籽粒硒含量平均增加到647.8μg·kg -1 ,达到了富硒水平,但没有达到中毒水平。每施用1.0 g Se·hm -2 ,籽粒硒含量平均提高5.3μg·kg -1 ,施用51 g Se·hm-2可将小麦籽粒硒含量从平均31.0μg·kg -1 提高到300μg·kg -1 以上。小麦籽粒硒含量不受产量的影响,但不喷硒时籽粒硒含量与0—20 cm土层土壤有效硒含量和拔节前植株硒含量分别呈显著和极显著正相关。土壤有效硒含量在6.3—30.7μg·kg -1 每增加1.0μg·kg -1 ,不喷硒时籽粒硒含量平均增加2.1μg·kg -1 ,拔节前植株硒含量在0—147.2μg·kg -1 每增加1.0μg·kg -1 ,不喷硒籽粒硒含量平均增加0.7μg·kg -1 。喷硒后籽粒硒含量和硒强化指数均与拔节前植株硒含量极显著正相关。拔节前植株硒含量每增加1.0μg·kg -1 ,喷硒籽粒硒含量平均增加5.7μg·kg -1 ,籽粒硒强化指数平均增加0.043μg·kg -1 （g·hm-2）-1。【结论】在农业生产中,通过拔节前土壤施硒提高土壤有效硒水平、在拔节中期或末期叶面喷施硒肥等,均可使植株累积较多的硒,并在灌浆期向籽粒转移,从而提高籽粒硒含量。

In order to understand the nutritional status of amino acids of China's wheat varieties, we collected 655 grain samples of wheat growing in 22 provinces from 2009 to 2011 and analyzed the content of total protein and 18 amino acids. The average grain protein contents of spring and winter wheat were 13.7% and 12.7%, respectively. In spring wheat, 45%, 22%, and 33% of samples met the protein standard for strong, medium, and weak gluten wheat, while the portion was 18%, 24%, and 58% in winter wheat, respectively. Spring wheat had higher contents in all amino acids except for tyrosine than winter wheat, but their ratios of essential to total amino acids were both 28.8%. Protein content decreased in the trend of from the north to the south, and from the east to the west. In addition, the single and the total essential amino acid content decreased from the east to the west. Lysine and tryptophan were the limiting amino acids in 98% and 2% of the wheat samples, respectively. The amino acid score varied across years, with an average of 53 in spring wheat and 56 in winter wheat. In conclusion, the overall protein content level of wheat grain was low in the sampling area. Particularly, the low contents and proportions of lysine and essential amino acids are limited factors in wheat protein nutrition.