Phosphorus status,use and recycling in a Chinese peri-urban region with intensive animal husbandry and cropping systems Results from case study in a Sino-German applied research collaboration project

The Sino-German research collaboration project, “Recycling of organic residues from agricultural and municipal origin in China” (2008–2012), comprising different interdisciplinary research groups, and also German small and medium-sized enterprises, aimed at developing integrated strategies and solutions for the recycling of organic residues in China. In an intensive crop-livestock agricultural region in the Shunyi District of Beijing, five typical cropping systems were investigated. The research was conducted in the form of analyses of phosphorus (P) in soil, plants, animal feed, animal products, manures, mineral and organic fertilizers and the derivation of the corresponding nutrient balances and P flows. The mean annual P balance surplus was 492 kg·ha⁻¹·yr⁻¹ P for the vegetable production system, significantly higher (P<0.05) than that for orchards (130 kg·ha⁻¹·yr⁻¹P) and cereal crops (83 kg·ha⁻¹·yr⁻¹ P). Plant-available P (Olsen-P) concentrations of topsoils (0–20 cm) had good correlations with the amounts of P applied (from mineral and organic sources). Compared to results from the Second Chinese National Soil Survey of 1981, mean concentrations of available P in soils of 19 plots investigated in Shunyi District increased 10-fold (from 7.3 to 60 mg·kg⁻¹) from 1981 to 2009. On average, the critical limit for Olsen-P concentrations (>30 mg·kg⁻¹) that can lead to increased risk of P loss was exceeded in all five cropping systems. With feed additives, the “natural background value” (Chinese Environmental Quality Standard for Soils) of copper and zinc in topsoils was exceeded at several sites. Screening for several substances in the veterinary antibiotic classes of sulfonamides, tetracyclines, and fluoroquinolones revealed widespread topsoil contamination. Calculated livestock densities were 10.6 livestock units per ha arable land in 2007. Animal husbandry is increasingly conducted in large operations, making traditional ways of reuse difficult to apply. Comparing three management systems for treatment of organic residues from a pig farm via aerobic (composting) or anaerobic (biogas) treatment in a life cycle assessment, the resulting cropland demand for a sustainable land application of biogas effluent varied between 139 and 288 ha·yr⁻¹, well above the cropland area owned by the farm (10 ha). The mismatch problems in the above context between business-as-usual and improving performance are framed and discussed as (1) the mismatch between centralized animal husbandry and smallholder farming, (2) the mismatch between livestock density and cropland, (3) nutrient (including P) recycling and increasing organic matter content versus energy production, (4) subsidies for compost production and biogas, as well as (5) advances in the regulatory framework in China.     

地膜覆盖与施肥对秸秆碳氮在土壤中固存的影响

[目的]作物秸秆不仅含有较高的有机碳,而且含有丰富的矿质营养元素.秸秆还田是东北黑土地区培肥土壤和农业可持续发展的重要技术措施.然而不同地膜覆盖(简称"覆膜")及施肥方式下秸秆碳(C)和氮(N)在土壤中的固持特征还不是很明确.本研究通过定量分析秸秆碳对土壤有机碳(SOC)和秸秆氮对土壤全氮(TN)的贡献,探讨不同覆膜和...     

EVALUATING QUINOA LODGING RISK AND YIELD UNDER DIFFERENT IRRIGATION THRESHOLDS,NITROGEN RATES AND PLANTING DENSITIES IN NORTH-WESTERN CHINA

● A moderate irrigation threshold of −25 kPa gave the greatest actual yield. ● Nitrogen rates of 80−160 kg·ha⁻¹ reduced lodging risk without yield decrease. ● Planting density of 30 plants·m⁻² provided both high yield and lodging resistance. ● A lower-stem lodging index was best for prediction of quinoa lodging risk. Lodging is a major yield-limiting factor of quinoa production. In 2018 and 2019, the orthogonal field experiments were conducted to investigate the responses of quinoa lodging risk and yield to irrigation threshold (soil matric potential of −15, −25 and −55 kPa), nitrogen rate (80, 160 and 240 kg·ha⁻¹) and planting density (20, 30 and 40 plants m⁻²). Results showed that high irrigation thresholds and nitrogen rates significantly (P < 0.05) increased plant height and fresh weight per plant, and high planting densities reduced stem diameter and strength, all of those led to significantly ( P < 0.05) high lodging risks. The −15 and −55 kPa treatments gave the lowest actual yield ( P < 0.05) in 2018 and 2019, respectively. Higher lodging rate with a nitrogen rate of 240 kg·ha⁻¹ resulted in a lower actual yield than 80 and 160 kg·ha⁻¹ in both years. Planting density of 30 plants m⁻² gave a significantly (P < 0.05) greater estimated yield than 20 plants m⁻² and had a lower lodging rate than 40 plants m⁻², resulting in the maximum actual yield among planting densities. In conclusion, a moderate irrigation threshold of −25 kPa, a nitrogen rate of 80−160 kg·ha⁻¹ and an intermediate planting density of 30 plants m⁻² were determined to be best for quinoa cultivation in North-western China. In addition, the lower-stem lodging index (quarter plant height) could evaluate lodging risk more accurately than middle-stem (half plant height) or upper-stem (three quarters plant height) lodging indexes.     

A potential solution for food security in Kenya: implications of the Quzhou model in China

Poor soil fertility due to low nutrient inputs is a major factor limiting grain production in Kenya. Increasing soil fertility for crop productivity in China has implications for food security in Kenya. The purpose of this study was therefore to investigate the historical patterns of grain production, nutrient inputs, soil fertility and policies in Quzhou, a typical agricultural county on the North China Plain, and to compare grain production in Quzhou County and Kenya to identify a potential approach for increasing grain production in Kenya. Grain yields in Quzhou increased from 1 to 3 t·ha⁻¹ between 1961 and 1987 by increasing manure application accompanied by small amounts of chemical fertilizer after soil desalinization. There was a further increase from 3 to 5 t·ha⁻¹ up to 1996 which can be mainly attributed to chemical fertilizer use and policy support. Hence, a beneficial cycle between soil fertility and plant growth in Quzhou grain production was developed and strengthened. In contrast, there was only a slight increase in grain yields in Kenya over this period, resulting from low soil fertility with limited external nutrient inputs, a consequence of poor socioeconomic development. It is suggested that grain yields in Kenya would likely be boosted by the development of a self-reinforcing cycling between soil fertility and plant growth with manure and chemical fertilizer use if supported by policy and socioeconomic development.     

不同根系分泌物对土壤N2O排放及同位素特征值的影响

【目的】探究植物根系分泌的主要组分（有机酸、氨基酸、糖类）对土壤N₂O排放及其微生物过程的影响,为选择适宜的植物进而控制土壤N₂O排放提供支撑。【方法】通过室内试验分别添加草酸、丝氨酸、葡萄糖于土壤中模拟根系的3种主要分泌物,每种分泌物设置两个浓度水平：低浓度（150 μg C·d ^-1）和高浓度（300 μg C·d ^-1）,另设置添加蒸馏水的对照组,共7个处理。将土壤置于120 mL玻璃瓶中进行培养,24 h内采集气体样品7次,每次培养2 h,获取N₂O排放速率、日累积排放量和同位素特征值（δ ¹⁵N ^bulk、δ ¹⁸O和SP（site preference,SP=δ ¹⁵N ^α-δ ¹⁵N ^β））。【结果】添加3种根系分泌物组分后,土壤N₂O排放速率均逐渐升高,且均高于对照。高浓度处理组N₂O累积排放量为：葡萄糖（（3.2±1.3）mg·kg ^-1·d ^-1）处理>丝氨酸（（2.6±0.5）mg·kg ^-1·d ^-1）处理>草酸（（1.4±0.2）mg·kg ^-1·d ^-1）处理,低浓度处理组为：草酸（（2.7±1.3）mg·kg ^-1·d ^-1）处理>丝氨酸（（1.8±0.4）mg·kg ^-1·d ^-1）处理>葡萄糖（（1.6±0.8）mg·kg ^-1·d ^-1）处理;添加根系分泌物的不同处理间土壤N₂O的δ ¹⁸O值无明显差异,并稳定在24.1‰—25.6‰,且均显著高于对照（（20.1±1.5）‰）;土壤N₂O的δ ¹⁵N ^bulk值与添加根系分泌物的种类有关,其中草酸处理组为（-20.06±2.22）‰、丝氨酸处理组为（-22.33±1.10）‰、葡萄糖处理组为（-13.86±1.11）‰、对照组为（-23.14±3.72）‰。各处理土壤N₂O的SP值的变化范围为13.13‰—15.03‰,根系分泌物浓度越高,SP值越低。综合分析不同处理4个指标（N₂O排放速率、N₂O的δ ¹⁵N ^bulk、δ ¹⁸O和SP值）的不同时刻的检测值与日均值的校正系数,添加根系分泌物后第16小时各处理4个指标的校正系数最接近于1。【结论】在NH+ 4-300 mg N·kg ^-1的土壤环境下根系分泌物促进N₂O的排放,且在培养期间（24 h）土壤N₂O排放速率逐渐升高。高浓度处理组葡萄糖对土壤N₂O排放速率促进效果最强,低浓度处理组草酸对土壤N₂O排放速率促进效果最强。与对照组相比,根系分泌物的添加使N₂O的δ ¹⁸O值显著升高;与对照组相比,葡萄糖的添加使δ ¹⁵N ^bulk值显著升高。根系分泌物浓度越高,反硝化作用对N₂O的贡献越大。     

不同供氮水平对蒙古栎幼苗生物量与光合特性的影响

采用盆栽试验方法,从1、4、8、16、32 mmol·L^-1 5个N素处理对蒙古栎幼苗的生物量、相关生理指标以及光合特性等方面的影响进行研究。结果表明,随着供N水平的提高,蒙古栎幼苗根、茎和全株的生物量均在N₁₆供应下达最高,但与N₈、N₃₂处理间差异不显著,叶片生物量在N₃₂水平达最大,与N₁₆的差异不显著。根冠比随着供N水平的提高呈现降低的趋势。蒙古栎幼苗的光合参数（P_n、T_r、G_s、C_i）随供N量的增加呈现出先增加后减小的趋势,均在N₈水平下达最大。除叶绿素b之外,叶绿素a、叶绿素总量、类胡萝卜素以及可溶性蛋白含量与光合参数的变化一致,同样在N₈水平达最大。试验结果表明,增加N素供应可促进蒙古栎幼苗的生物量,或高或低的供N都会影响蒙古栎幼苗的光合作用。     

稳定同位素技术在肉羊产地溯源中的应用

[目的]通过比较不同部位羊肉中碳氮稳定同位素差异,以及对羊肉、全骨粉、脱脂骨粉与骨胶原的稳定同位素分析,为肉羊产地溯源鉴别提供技术支持.[方法]利用同位素比率质谱仪(IRMS)测定不同部位脱脂羊肉中δ13C和δ15N值,进而比较不同产地来源(新西兰和中国宁夏、甘肃、安徽)的羊肉、全骨粉、脱脂骨粉与骨胶原中δ13C和δ1...     

NEW ZEALAND DAIRY FARM SYSTEMS AND KEY ENVIRONMENTAL EFFECTS

• NZ dairy farming systems are based on year-round grazing of perennial pasture (ryegrass/white clover). • Milk production per hectare has increased by about 29% with increased use of externally-sourced feeds over the last two decades. • Externally-sourced feeds with a low protein concentration can potentially reduce N₂O emissions and N leaching per unit of production. • Systems analysis is important for evaluating mitigations to minimize trade-offs between environmental impacts. This paper provides an overview of the range of dairy pasture grazing systems used in New Zealand (NZ), the changes with increased inputs over time and associated key environmental effects including nitrogen (N) leaching and greenhouse gas (GHG) emissions. NZ dairy farming systems are based on year-round grazing and seasonal milk production on perennial ryegrass/clover pasture where cows are rotationally grazed in paddocks. There was an increase in stocking rate on NZ dairy farms from 2.62 cows ha⁻¹ in 2000/2001 to 2.84 cows ha⁻¹ in 2015/2016. During the same period annual milk solids production increased from 315 to 378 kg·yr⁻¹ per cow. This performance has coincided with an increase in N fertilizer use (by ~ 30%) and a twofold increase in externally-sourced feeds. Externally-sourced feeds with a low protein concentration (e.g., maize silage) can increase the efficiency of N utilization and potentially reduce N losses per unit of production. Off-paddock facilities (such as standoff or feed pads) are often used to restrict grazing during very wet winter conditions. A systems analysis of contrasting dairy farms in Waikato (largest NZ dairying region) indicates that the increased input would result in an increase in per-cow milk production but little change in efficiency of milk production from a total land use perspective. This analysis also shows that the increased inputs caused an 11% decrease in N footprint (i.e., N emissions per unit of milk production) and a 2% increase in C footprint (i.e., greenhouse gas (GHG) emissions per unit of milk production).     

不同施氮量与栽插密度对水稻群体生长及产量构成的影响

【目的】 研究不同施氮量和栽插密度对新疆南疆水稻群体生长及产量特征的影响,为生产中合理密植与优化氮素优化管理提供依据。【方法】 选用新稻36号品种,设置主区为4种施氮量(纯氮0、120、240和360 kg/hm²,以N₀、N₁、N₂和N₃表示),副区为5种栽插密度(13.89×10⁴、16.67×10⁴、20.83×10⁴、27.78×10⁴和41.67×10⁴穴/hm²,以D₁、D₂、D₃、D₄和D₅表示)的裂区田间试验,分析茎蘖动态、干物质积累、产量构成与米质特征。【结果】 (1)适当增加栽插密度和施氮量有利于提高水稻群体茎蘖数,以N₂D₄的最终茎蘖数最大,达412.80×10⁴个/hm²;(2)南疆水稻群体干物质快速增长期在拔节前后至灌浆中后期,且随施氮量增加有延长趋势,其最终干物质积累量表现为N₃>N₂>N₁>N₀。密度过高不利于群体干物质积累,其最终干物质积累量表现为D₄>D₅>D₃>D₂>D₁;(3)N₂和D₁的穗粒数最大,施氮量过高,对提高结实率、粒重和分蘖成穗率不利。随施氮量及栽插密度增加,有效穗数和产量呈先增后降的趋势,以N₂D₄的有效穗数和产量最大,分别达399.08×10⁴穗/hm²和13.61 t/hm²,其次是N₃D₄,为371.46×10⁴穗/hm²和12.94 t/hm²;(4)密度对米质影响不大,增施氮肥利于蛋白质含量、糙米率、精米率增加,提高品质。【结论】 施氮量240~360 kg/hm²、栽插密度27.78×10⁴穴/hm²(30 cm×12 cm)可获得较高产量。     

花后高温干旱胁迫下氮素对冬小麦氮积累与代谢酶、蛋白质含量及水氮利用效率的影响

【目的】 本研究基于气候室模拟温度日变化特征,旨在探讨氮素对高温、干旱及复合胁迫下冬小麦地上干物质重、氮积累与分配、氮代谢相关酶活性、蛋白质含量、产量及水氮利用效率的影响。【方法】 基于人工气候室开展冬小麦盆栽试验,以小偃22号为试验材料,采用裂-裂区随机完全区组设计,以2个温度处理（高温：H;适宜温度：S）为主区,以2个水分水平（干旱：D;充分供水：F）为裂区,3个施氮水平（低氮：N₁;中氮：N₂;高氮：N₃）为裂-裂区,研究冬小麦生长生理特性、产量及水氮利用效率对高温干旱胁迫及各施氮量的响应特征。【结果】 高温、干旱及复合胁迫导致地上总干物质重（ADW）和氮积累量（ANA）降低。在成熟期,高温干旱复合胁迫（HD）和干旱胁迫（SD）下N₃处理ANA分别较N₁处理增加7.26%和6.82%。高温、干旱及复合胁迫提高小麦花前氮素对籽粒贡献率（NRR）,HD胁迫各施氮处理NRR均值较对照（SF）增加达38.21%,施氮量的增加扩大这种增加效应。高温、干旱及复合胁迫导致成熟期穗氮分配率降低,特别是复合胁迫。暴露于高温、干旱及复合胁迫下籽粒蛋白质产量（PY）降低,干旱胁迫（7.37%）各施氮处理PY均值较高温胁迫（3.94%）降低更多,无论单一或复合胁迫下籽粒PY均在N₂处理下显著增加。此外,单一的干旱和高温胁迫下降低的谷氨酰胺合成酶（GS）和硝酸还原酶（NR）活性在N₂处理下显著增加,复合胁迫N₁处理NR和GS活性分别较N₃处理提高23.81%和23.07%。与对照相比,干旱胁迫各施氮处理穗粒数、千粒重和产量均值的降幅均高于高温胁迫,N₂处理对高温和干旱胁迫下这些参数存在明显正向调控,产量水分利用效率（WUE_g）和生物量水分利用效率（WUE_b）在N₂处理下得到明显改善。充分供水+N₂处理籽粒（NUE_g）分别较低干旱和复合胁迫N₃处理提高19.09%和19.44%,表明在水分充足条件下中氮能有效地缓解干旱和高温胁迫下籽粒氮利用效率的降低。NUE_g和NUE_b的提高可能归因于合理氮肥调控下增加的GS和NR活性。主成分分析表明胁迫条件下小麦千粒重和ADW与产量的关系更紧密。【结论】 高温和干旱胁迫的综合效应比单一胁迫对小麦危害更大。在单一高温和干旱胁迫下,适量增加氮输入能增加氮代谢酶活性并维持更高氮代谢能力,提高籽粒氮积累量及蛋白质产量,将更有利于提高产量及水氮利用效率。然而在花后遭遇高温干旱复合胁迫时,相比低施氮量,增加施氮对小麦产量形成及水氮的吸收利用均产生一定抑制作用,应适当减少氮肥用量。     

Synthesis and characterization of castor oil-based polymeric surfactants

Dehydrated castor oil was epoxidized using phosphoric acid as a catalyst and acetic acid peroxide as an oxidant to produce epoxidized castor oil (ECO). Ring-opening polymerization with stannic chloride was used to produce polymerized ECO (PECO), and sodium hydroxide used to give hydrolyzed PECO (HPECO). The HPECO was characterized by Fourier transform infrared, ¹H and ¹³C nuclear magnetic resonance spectroscopies, gel permeation chromatography, and differential scanning calorimetry. The weight-average molecular weight of soluble PECO and HPECO were 5026 and 2274 g·mol^-1, respectively. PECO and HPECO exhibited glass transition. Through neutralizing the carboxylic acid of HPECO with different counterions, castor oil-based polymeric surfactants (HPECO-M, where M= Na⁺, K⁺ or triethanolamine ion) exhibited high efficiency to reduce the surface tension of water. The critical micelle concentration (CMC) values of HPECO-M ranged from 0.042 to 0.098 g·L^-1 and the minimum equilibrium surface tensions at CMC (g_cmc) of HPECO-M ranged from 25.6 to 30.0 mN·m^-1. The water-hexadecane interfacial energy was calculated from measured surface tension using harmonic and geometric mean methods. Measured values of water-hexadecane interfacial tension agreed well with those calculated using the harmonic and geometric mean methods.     

Quantifying in situ N2 fluxes from an intensively managed calcareous soil using the 15N gas-flux method

Denitrification-induced nitrogen (N) losses from croplands may be greatly increased by intensive fertilization.  However, the accurate quantification of these losses is still challenging due to insufficient available in situ measurements of soil dinitrogen (N₂) emissions.  We carried out two one-week experiments in a maize–wheat cropping system with calcareous soil using the ¹⁵N gas-flux (¹⁵NGF) method to measure in situ N₂ fluxes following urea application.  Applications of ¹⁵N-labeled urea (99 atom%, 130–150 kg N ha⁻¹) were followed by irrigation on the 1st, 3rd, and 5th days after fertilization (DAF 1, 3, and 5, respectively).  The detection limits of the soil N₂ fluxes were 163–1 565, 81–485, and 54–281 μg N m⁻² h⁻¹ for the two-, four-, and six-hour static chamber enclosures, respectively.  The N₂ fluxes measured in 120 cases varied between 159 and 2 943 (811 on average) μg N m⁻² h⁻¹, which were higher than the detection limits, with the exception of only two cases.  The N₂ fluxes at DAF 3 were significantly higher (by nearly 80% (P<0.01)) than those at DAF 1 and 5 in the maize experiment, while there were no significant differences among the irrigation times in the wheat experiment.  The N₂ fluxes and the ratios of nitrous oxide (N₂O) to the N₂O plus N₂ fluxes following urea application to maize were approximately 65% and 11 times larger, respectively (P<0.01), than those following urea application to wheat.  Such differences could be mainly attributed to the higher soil water contents, temperatures, and availability of soil N substrates in the maize experiment than in the wheat experiment.  This study suggests that the ¹⁵NGF method is sensitive enough to measure in situ N₂ fluxes from intensively fertilized croplands with calcareous soils.     

施肥对菜地土壤、蔬菜、径流中δ15N组成的影响

为了解施肥对蔬菜地土壤、蔬菜和地表水体中δ¹⁵N丰度的影响,选择2012至2018内施用不同肥料的28块蔬菜地（包括13块施用化肥蔬菜地、8块施用畜禽粪蔬菜地和7块施用商品有机肥加化肥蔬菜地）,采样分析表层土壤、蔬菜地上部分和地下部分及地表径流样的δ¹⁵N丰度。结果表明：施肥种类对土壤、蔬菜和地表径流中δ¹⁵N丰度均可产生显著影响,其丰度值由高至低依次为：畜禽肥>商品有机肥加化肥>化肥。蔬菜和地表水与土壤之间的δ¹⁵N丰度存在正相关。分析认为,蔬菜产品中氮同位素组成可以作为鉴定有机蔬菜的辅助依据,地表水体中δ¹⁵N丰度可作为水体中氮素污染源的指标。     

减氮配施有机肥对滴灌春小麦花后同化物转运和籽粒灌浆特性的影响

[目的]研究减氮条件下新疆滴灌小麦高产高效的调控途径,分析滴灌春小麦花后同化物转运和籽粒灌浆特性的调控效应,为新疆滴灌春小麦的高产优质栽培提供科学依据.[方法]设置不同减氮配施有机肥处理,采用裂区设计,氮素为主区,品种为副区;于2019年在田间滴灌条件下设置7种减氮配施有机肥水平(NCK、N5、N10、N15、N20、...     

不同生育期成龄灰枣树茎流速率与气象因子的关系

【目的】在微喷灌的灌溉方式下,研究不同天气和不同气象因子条件下成龄灰枣树的茎流速率,精准测定出成龄枣树的耗水量,为优化枣树的土壤水分管理提供生产指导。【方法】采用针式茎流计,连续监测灰枣树茎流速率,分析枣树的茎流速率受不同天气和气象因子的影响程度。【结果】晴天和阴天茎流速率的波动变化过程呈倒“U”型的单峰曲线,而多云天气下呈“M”型的双峰曲线。1 d中枣树的茎流累积趋势呈“S”变化,各生育期耗水量大小排序为果实膨大期>成熟期>花期>萌芽展叶期。只有成熟期枣树的茎流速率与空气温度相关程度最高,其余都是太阳辐射。各生育期太阳辐射与枣树茎流速率的相关系数R_D1=0.964^**、R_D2=0.969^**、R_D3=0.957^**和R_D4=0.886^**。利用多元线性回归在枣树的各生育期内对茎流速率和气象因子进行输入回归,建立不同天气条件下,各生育期枣树茎流速率和气象因子的多元线性回归模型,经过回归系数和相关系数检验,各生育期的多元线性回归方程均达到了显著水平。【结论】各生育期内,典型天气的茎流速率排序为晴天>多云>阴天,整个生育期中的需水关键期是果实膨大期,对枣树的茎流速率产生最大影响的气象因子是太阳辐射和空气温度。     

葡聚糖改性尿素对冬小麦产量和肥料氮去向的影响

【目的】糖类物质具有调控氮素转化和作物生长的作用，目前尚不明确不同聚合度糖类物质与尿素反应对尿素氮肥利用、作物生长的影响及机理。通过将不同聚合度葡萄糖（葡聚糖）与¹⁵N尿素熔融制备葡聚糖改性尿素，分析葡聚糖改性尿素的结构变化与小麦产量和氮素吸收利用的关系，以期为葡聚糖在提高尿素氮肥利用效率中的应用提供科学依据。【方法】采用¹⁵N示踪技术，供试作物为冬小麦（济麦22），将葡萄糖（单体）、麦芽糖（2聚）、低聚麦芽糖（≈5聚）和聚葡萄糖（≈20聚）按1%添加量加入到熔融¹⁵N尿素（丰度为10.19%）中，制得葡聚糖改性尿素（葡萄糖、麦芽糖、低聚麦芽糖、聚葡萄糖改性尿素分别由GU、MU、OU和PU表示），以不同聚合度葡萄糖改性尿素和普通尿素（U）为供试肥料，运用田间土柱栽培试验研究葡聚糖改性尿素对小麦生长及肥料氮去向的影响。利用傅里叶红外变换（FTIR）光谱和¹³C核磁共振（¹³C NMR）波谱特征探究葡萄糖聚合度及其改性尿素的结构变化，并揭示其与小麦产量、氮肥利用的关系。【结果】（1）与U相比，葡聚糖改性尿素的FTIR谱图在3 343和1 601 cm^-1处的伯酰胺振动强度减弱，¹³C NMR波谱在158—171 ppm处检测到一个新的化学位移峰，是葡聚糖的醛基与尿素的胺基发生席夫碱反应，生成含C=N物质的标志。（2）与U相比，不同聚合度葡萄糖改性尿素（GU、MU、OU、PU）增加了小麦产量，分别较U提高了1.9%、9.2%、10.3%和12.3%，主要通过增加小麦穗数和穗粒数实现增产。（3）与U相比，不同聚合度葡萄糖改性尿素的小麦籽粒总氮吸收量和肥料氮吸收量分别提高了8.7%—20.0%和6.1%—13.9%；MU、OU和PU处理的氮素吸收量均高于GU。（4）与U相比，不同聚合度葡萄糖改性尿素的¹⁵N利用率提高了2.0—6.1个百分点，肥料氮残留率提高了1.3—4.9个百分点，肥料氮损失率显著降低6.9—7.4个百分点。（5）相关性分析结果表明，小麦产量与葡萄糖聚合度呈显著正相关关系，而与席夫碱含量呈显著负相关；利用一元二次方程可显著拟合席夫碱含量与小麦产量和¹⁵N利用率的关系，葡萄糖聚合度5—8时，小麦产量和肥料氮利用率最高。【结论】与普通尿素相比，不同聚合度葡萄糖改性尿素可以增加小麦产量，促进氮素的吸收利用，提高肥料氮残留量，减少尿素氮肥损失。一定范围内，随着葡聚糖聚合度的增加，小麦产量和肥料氮吸收量逐渐增加，土壤中肥料氮残留量逐渐降低。葡萄糖聚合度为5—8，其对尿素改性增效的效果最佳。     

施氮对毛竹笋营养成分的影响

  目的  探讨氮沉降对毛竹Phyllostachys edulis笋品质的影响,为竹笋品质改善和人体保健提供理论依据。  方法  通过人工喷氮模拟氮沉降方法,研究了3种不同水平的氮沉降[0 kg·hm?2·a?1(对照)、30 kg·hm?2·a?1(低氮,N₃₀)和60 kg·hm?2·a?1(高氮,N₆₀)]对毛竹笋不同氨基酸、营养成分(维生素C、粗纤维、粗蛋白质、可溶性糖)和矿质元素质量分数的影响。  结果  氮沉降对毛竹笋营养品质和矿质元素影响显著,氮沉降显著增加了总氨基酸、必需氨基酸和甜味氨基酸的质量分数(P＜0.05),高氮沉降显著提高了鲜味、苦味和芳香类氨基酸的质量分数(P＜0.05),而低氮沉降则相反;同时,氮沉降显著提高了毛竹笋中甜味氨基酸比例(P＜0.05),显著降低了必需、鲜味、苦味和芳香类氨基酸比例(P＜0.05);氮沉降显著降低了毛竹笋中维生素C质量分数(P＜0.05),但却提高了粗纤维质量分数,对粗蛋白质和可溶性糖质量分数影响不显著;氮沉降显著提高了硒、铁和钠(P＜0.05)质量分数,显著降低了铜(P＜0.05)质量分数,低氮沉降显著增加了锰、钙和镁(P＜0.05)质量分数,而高氮沉降则相反。  结论  适度的氮沉降对毛竹笋营养成分有一定的提升作用,有利于竹笋品质的改善和人体保健。图2表2参41     

不同基因型水稻磷营养的差异性研究

为了筛选磷高效基因型水稻种质,以14个不同基因型水稻为供试材料,对低磷和正常供磷处理下水稻分蘖期的生物学性状、磷的吸收利用效率、成熟期产量及其产量构成因素的差异进行了研究。结果表明,低磷胁迫明显影响水稻的生长,分蘖期的株高、分蘖数、干物质量、磷吸收效率、单株产量分别低于正常供磷处理5.9~14.5cm,4.5~14.8,2.15~7.53 g/株,5.35~14.46 mg/株,0.5~13.4 g,而根冠比和磷利用效率分别高于正常供磷处理0.01~0.08,133.8~416.4 g/g,且不同基因型水稻间差异显著。说明筛选具有较高磷吸收利用效率和较高产量的水稻种质是可行的。     

水氮耦合对滴灌冬小麦氮素吸收、 转运及产量的影响

【目的】 研究南疆滴灌冬小麦氮素吸收和利用特征,为揭示滴灌冬小麦氮素高效利用机制打下基础。【方法】 以新冬22号为材料,开展水氮裂区设计试验,滴施纯氮为主区,设N₁(138 kg/hm²)、N₂(207 kg/hm²)、N₃(276 kg/hm²)和N₀(对照,不施氮肥)4个水平;滴水量为副区,在统一冬灌900 m³/hm²的基础上,起身期以后设W₁(1 800 m³/hm²)、W₂(3 150 m³/hm²)、W₃(4 500 m³/hm²)3个滴灌水平,共12个处理。【结果】 (1)适当增加水氮供应量有利于提高冬小麦植株氮素积累量,其中N₃W₂、N₃W₃、N₂W₂和N₂W₃处理的积累量显著高于其他处理。(2)开花前是氮素积累量的主要时期,其平均积累量占总积累量的78.28%,拔节-扬花期是氮素吸收速率高峰期,并以N₃W₂、N₂W₃和N₂W₂处理最高,分别达6.38、5.81和5.01 kg/(hm²·d)。(3)各器官氮素转运量及对籽粒氮素积累的贡献率大小为叶片>茎鞘>颖壳+穗轴;N₃W₂和N₂W₃处理的营养器官氮素转移量显著高于其他处理,达158.34和147.49 kg/hm²;N₃W₂、N₂W₂和N₂W₃处理的籽粒蛋白质含量及蛋白质产量显著高于其他处理,分别达15.73%、15.41%和14.18%及1 475.94、1 256.97和1 217.78 kg/hm²。(4)滴灌冬小麦的产量构成及水、氮利用效率具有显著的水氮耦合效应,N₃W₂、N₂W₃和N₂W₂处理的产量较高,其氮肥农学利用率、氮肥利用效率及灌溉水利用效率也最大。【结论】 207~276 kg/hm²的施氮量和3 150~4 500 m³/hm²的春季滴水量是该地区较合适的水氮供应范围,当施氮量为275.08 kg/hm²和滴水量为4 457.89 m³/hm²包括冬灌900 m³/hm²时,产量可达最大为8 558.73 kg/hm²。     

基施氮肥及灌浆前期喷施锌肥对小麦籽粒富锌及蛋白组分含量的影响

【目的】叶面喷锌（Zn）是提高小麦籽粒锌含量进而解决人体缺锌问题的有效农艺措施。探明不同施氮（N）量下叶面喷锌后小麦全粒及面粉中的富锌效果及对蛋白组分含量的影响。【方法】基于长期定位试验,于2018—2020年连续进行了两年裂区田间试验。以基施不同用量氮肥（N₀、N₁₂₀、N₂₄₀,施N量分别为0、120、240 kg∙hm^-2）为主区,副区为灌浆前期喷施锌肥处理（Zn₀、Zn₁,分别为喷H₂O、喷0.4% ZnSO₄·7H₂O）,测定了灌浆前期和成熟期各部位锌含量、叶片等营养器官中锌向籽粒的转移量及分配、籽粒和面粉中蛋白质及其组分含量。【结果】与N₀相比,N₁₂₀和N₂₄₀处理籽粒产量显著提高,增幅达88%—114%,但N₁₂₀和N₂₄₀处理之间并无显著差异。叶面喷锌均能显著提高小麦籽粒和面粉锌含量且籽粒达富锌标准,而不受施氮量的影响,其中,N₁₂₀、N₂₄₀处理小麦籽粒锌含量分别比N₀处理提高0.95和1.12倍。与N₀相比,施用氮肥均提高了小麦灌浆前期叶片等营养器官中氮、锌向籽粒的转移量,但降低了二者的转移比例,其中氮转移比例由60.2%下降至48.6%,锌由55.4%下降至42.3%。无论喷锌与否,氮、锌向籽粒的转移量及成熟期籽粒中氮、锌含量均呈显著线性正相关,且喷锌时氮、锌协同效应更为显著。与灌浆前期相比,成熟期小麦籽粒和面粉中储藏蛋白（醇溶蛋白和谷蛋白）含量显著增加,约占蛋白含量的80%—84%。施氮对籽粒和面粉中醇溶蛋白和谷蛋白含量提升幅度高于清蛋白和球蛋白,且以谷蛋白最大,而喷锌不影响籽粒和面粉中蛋白质及其组分含量,但在Zn₁条件下,施氮对籽粒和面粉中谷蛋白含量的提高幅度高于Zn₀条件下,分别提升37.5%和38.1%。【结论】叶面喷锌能够实现籽粒富锌,但不影响籽粒和面粉中蛋白质及其组分含量,表明籽粒和面粉中存在足够的用于锌储存的蛋白质库。因此在潜在缺锌石灰性土壤上,通过合理施用氮肥结合小麦灌浆前期叶面喷锌,能在保证小麦高产稳产的同时提高籽粒氮、锌营养品质。