Improvement in Reproductive Development,Seed Yield,and Quality in Wheat by Zinc Application to a Soil Deficient in Zinc

A pot experiment was done to study the effect of zinc (Zn) application on the reproductive development and quality of wheat (Triticum aestivum L. cv. SP 343) seeds. The soil was low in diethylenetriaminepentaacetate (DTPA)–extractable Zn and was fortified with a mixture of nitrogen, phosphorus, and potassium (NPK) as basal fertilizers. Four treatments included a control (no Zn), 5 mg Zn, 10 mg Zn, and 10 mg Zn kg^?1 soil with urea instead of ammonium nitrate. Zinc addition improved the pollen-producing capacity of anthers, pollen viability, and seed yield with an increase in seed Zn, phytate, and starch contents but decreased the phytate/zinc molar ratio at 5 mg Zn kg^?1 and increased it at 10 mg Zn kg^?1. Application of urea increased the seed protein content at 10 mg Zn kg^?1 but was ineffective in lowering the phytate/Zn ratio, which was still less than the alarming level.     

Response of Wheat Plants to Zinc,Iron, and Manganese Applications and Uptake and Concentration of Zinc,Iron, and Manganese in Wheat Grains

This experiment was conducted at Zahak Agricultural Research Station in the Sistan region in southeast Iran. A factorial design with three replications was used to determine the effects of zinc (Zn), iron (Fe), and manganese (Mn) applications on wheat yield, Zn, Fe, and Mn uptakes and concentrations in grains. Four levels of Zn [soil applications of 0, 40, and 80 kg ha^?1 and foliar application of 0.5% zinc sulfate (ZnSO₄) solution], two levels of iron sulfate (FeSO₄; 0 and 1%) as foliar application, and two levels of Mn (0 and 0.5%) also as foliar application were used in this study. Results showed that the interactive effects of Zn and Mn were significant on the number of grains in each spike. The highest number of grains resulted from the application of 80 kg ZnSO₄ ha^?1 and foliar Mn. The interactive effects of Zn and Fe were significant on weight of 1000 grains. The highest weight of 1000 grains resulted from application of 80 kg Zn and foliar Fe. Application of 80 kg ZnSO₄ ha^?1 alone and 80 kg ZnSO₄ ha^?1 with foliar application of Mn significantly increased grain yield in 2003. The 2‐year results showed that foliar application of Zn increased Zn concentration and Fe concentration in grains 99% and 8%, respectively. Foliar application of Fe resulted in a 21% increase in Fe concentration and a 13% increase in Zn concentration in grains. The foliar application of Mn resulted in a 7% increased in Mn concentration in grains.     

低锌旱地土施锌肥对小麦产量和锌利用的影响

土壤有效锌含量低是制约西北旱地冬小麦籽粒锌营养品质的关键问题。采用连续两年的田间定位试验,设0、10、25、50、100、150kg·hm。6个锌肥（ZnSO4·7H2O）水平,研究了施锌对小麦产量、籽粒锌含量和土壤有效锌含量的影响,分析了西北旱地冬小麦土施锌肥的可行性。结果表明,随锌肥用量增加,土壤有效锌含量显著提高,但小麦产量无明显变化,小麦籽粒锌含量两季最高值分别为19．8、32.1mg·kg^-1,比不施锌提高32％和44％,却依然低于40-60mg·kg^-1的推荐含量,总锌利用率不到1％。因此,在西北旱地,不建议通过土施锌肥来提高小麦籽粒锌含量。     

氮锌配施对不同玉米品种灌浆期生理特性和籽粒氮锌含量的影响

提高粮食作物中可食部分的锌生物有效性是解决人体缺锌的重要措施。为研究氮锌肥料施用对玉米籽粒锌营养的影响,本研究以郑单958和谷神玉66为试验材料,在大田条件下研究3个氮水平(90、180 和225 kg N·hm^-2)和2个喷锌处理(0和4.5 kg·hm^-2 ZnSO₄·7H₂O)下玉米籽粒产量和氮锌含量以及灌浆期叶片生理特性的变化。结果表明,吐丝后,与施氮量90 kg·hm^-2处理相比,施氮量180和225 kg·hm^-2处理提高了吐丝后穗位叶SPAD值及硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、碳酸酐酶(CA)、超氧化物歧化酶(SOD)活性和灌浆后期PSⅡ综合性能指数(PI),降低了丙二醛(MDA)含量。施锌能提高吐丝后穗位叶CA、SOD、过氧化物酶(POD)、过氧化氢酶(CAT)活性和灌浆后期SPAD值和PI,降低MDA含量。2个品种相比,谷神玉66灌浆后期穗位叶SPAD值、叶片初始荧光(F_o)和最大荧光(F_m)较高,而灌浆前期穗位叶PI和吐丝后NR、CA、SOD以及POD活性则以郑单958较高。施氮量为90 kg·hm^-2时,玉米籽粒产量平均为8.55 t·hm^-2,随着施氮量增加,玉米籽粒产量显著提高。籽粒中氮含量以施氮量180 kg·hm^-2时最高,为14.85 g·kg^-1。施氮量90和180 kg·hm^-2时,籽粒锌含量平均为27.2 mg·kg^-1,显著高于施氮量225 kg·hm^-2处理。与不施锌相比,喷锌后玉米籽粒产量未有显著变化,籽粒中氮、锌含量分别增加了11.7%和18.0%。郑单958籽粒产量较谷神玉66提高了3.8%,籽粒氮锌含量则分别减少了11.9%和5.3%。综合来看,施氮量为180 kg N·hm^-2时,与喷施ZnSO₄·7H₂O 4.5 kg·hm^-2 配合施用能够增强玉米灌浆期叶片SPAD和荧光特性,提高氮锌代谢关键酶活性,增强氧自由基清除系统酶活性,减弱膜脂过氧化作用的伤害,促进籽粒中氮、锌的吸收和累积。本研究结果可为玉米生产中优化锌生物强化措施提供理论依据。     

Morpho-physiological Response of Saffron (Crocus Sativus L.) to Particle Size and Rates of Zinc Fertilizer

A field study was conducted during 2015–2017 in order to evaluate effects of the foliar application of different sources and concentrations of zinc oxide (ZnO) on the yield and morpho-physiological characteristics of saffron. Experimental treatment included the foliar application of nano ZnO at a concentration of (3, 6, and 9 g L^?1), foliar application of normal ZnO at a concentration of (3, 6, and 9 g L^?1) and the control. Both types of ZnO had positive effects on the saffron yield and number of flowers, but the highest yield and flower number were obtained by the foliar application of 9 g L^?1 normal ZnO followed by 6 g L^?1 nano ZnO. Increasing concentrations of both fertilizers up to 3 g L^?1 had no significant effect on crocin, but the crocin content significantly decreased at higher concentrations. Effects of experimental treatments were significant on all morpho-physiological traits. The maximum chlorophyll a (1.74 mg.g^?1) was observed in normal ZnO at a concentration of 9 g L^?1 followed by nano ZnO at a concentration of 3 g L^?1. The increasing application of different types of fertilizers linearly increased the Peroxidase activity, but the highest activity of Catalase in normal ZnO and nano ZnO was measured after the foliar application at concentrations of 3 and 6 g L^?1, respectively.     

我国主要麦区小麦籽粒锌含量对叶喷锌肥的响应

【目的】我国小麦籽粒锌含量普遍偏低,叶喷锌肥是提高小麦籽粒锌含量的重要措施,研究我国主要麦区小麦籽粒锌含量对叶喷锌肥的响应,对小麦科学施用锌肥、 调控小麦籽粒锌营养状况有重要意义。【方法】本研究在我国14个省(市)主要麦区布置了30个田间试验,在每个试验点设置不喷锌对照和叶面喷锌两个处理,以当地主栽小麦品种为供试作物,通过测定收获期小麦产量、 各器官锌含量,研究了叶喷锌肥提高小麦籽粒锌含量的效果、 区域差异及其与土壤主要理化性质、 小麦拔节前植株锌含量的关系。【结果】 30个试验点的结果显示,叶面喷锌对小麦籽粒产量、 生物量和收获指数均无明显影响,但籽粒锌含量显著提高,叶面喷锌的籽粒锌含量比对照平均提高5.2 mg/kg(17.5%), pH7.0的区域提高5.3 mg/kg(16.4%), pH 7.0的区域提高5.2 mg/kg(18.4%)。小麦地上部锌吸收与分配在两个区域间没有显著差异,叶面喷锌的小麦籽粒、 颖壳和茎叶平均锌吸收量分别为255.5、 26.0和117.5 g/hm2,比对照增加19.4%、 28.7% 和99.2%; 锌收获指数为64.1%,比对照降低12.2%。籽粒锌利用率和籽粒锌强化指数也不受区域的影响,平均值锌利用率为3.0%,锌强化指数为3.8 mg/kg。无论叶面喷锌与否,籽粒锌含量和土壤有效锌均呈显著正相关,土壤有效锌含量每升高1.0 mg/kg,籽粒锌含量平均提高约4.0 mg/kg; 籽粒锌含量和土壤pH呈显著负相关,土壤pH每升高1个单位,籽粒锌含量平均降低3.8 mg/kg; 籽粒锌含量与土壤有机质没有显著相关性。小麦籽粒锌含量与拔节前植株锌含量极显著正相关,拔节前植株锌含量每升高1.0 mg/kg,籽粒锌含量平均提高0.4 mg/kg。【结论】 除叶面喷施锌肥外,调节土壤酸碱性,提高土壤有效锌含量,促进小麦生长前期植株对锌的吸收对改善我国小麦锌营养均具有重要意义。     

Response of Winter Wheat to Chloride Fertilization in Sandy Loam Soils

Abstract

Chloride (Cl) as a yield and growth‐limiting nutrient has been the object of experimental attention for the last several decades. Long‐term experiments were conducted from 1996 to 2002 at Hennessey and Perkins, Oklahoma to evaluate the response of winter wheat grain yield and nitrogen (N) uptake to 0, 15 and 30 kg Cl ha^?1 rates. A randomized complete block experimental design with three replications was used at both sites. Grain yield data were subjected to statistical analysis using SAS. Polynomial Orthogonal contrasts were used to detect trends in grain yield and N uptake to chloride levels. Chloride fertilizer significantly increased wheat grain yields in 50% of the site‐year combinations (14 total site years), and the increases were more notable on the sandy loam soil included in this study.     

拔节期土壤施锌对小麦籽粒中锌生物有效性影响评估

本研究通过2012—2013及2013—2014两个年度的田间试验,在小麦(扬麦-16)的拔节期土壤施加高用量的锌肥,通过植酸/锌摩尔比法,对小麦籽粒进行了锌生物有效性评价,每公顷施ZnSO4·7H2O的量达到300 kg能显著提高小麦籽粒锌含量,小麦籽粒锌含量达到60 mg/kg以上,小麦籽粒植酸/锌摩尔比显著降低,植酸/锌摩尔比最大可降低至15以下,表明小麦锌强化后籽粒中锌的生物有效性得到显著提高。     

Zinc biofortification of bread wheat,triticale, and durum wheat cultivars by foliar zinc fertilization

Poor zinc (Zn) nutrition of wheat is one of the main causes of poor human health in developing countries. A field experiment with no zinc and foliar zinc application (0.5% ZnSO₄.7H₂O) on bread wheat (8), durum wheat (3), and triticale (4) cultivars was conducted in a randomized block design with three replications in 2 years. The experimental soil texture was loamy sand with slightly alkalinity. The grain yields of bread wheat, triticale, and durum wheat cultivars increased from 43.6 to 56.4, 46.5 to 51.6, and 49.4 to 53.5 t ha^?1, respectively, with foliar application of 0.5% ZnSO₄.7H₂O. The highest grain yield was recorded by PBW 550 (wheat), TL 2942 (triticale), and PDW 291 (durum), which was 5.22, 4.24, and 4.56% and significantly higher over no zinc. Foliar zinc application increased zinc in bread wheat, triticale, and durum wheat cultivars grains varying from 31.0 to 63.0, 29.3 to 61.8, and 30.2 to 62.4?mg kg^?1, respectively. So, agronomic biofortification is the best way which enriching the wheat grains with zinc for human consumption.     

Cadmium Uptake by Winter Wheat Seedlings in Response to Interactions Between Phosphorus and Zinc Supply in Soils

ABSTRACT

Effects of application of zinc (Zn) (0, 1, 5, 10 mg kg^?1 soil) and phosphorus (P) (0, 10, 50, 100 mg kg^?1 soil) on growth and cadmium (Cd) accumulations in shoots and roots of winter wheat (Triticum aestivum L.) seedlings were investigated in a pot experiment. All soils were supplied with a constant concentration of Cd (6 mg kg^?1 soil). Phosphorus application resulted in a pronounced increase in shoot and root biomass. Effects of Zn on plant growth were not as marked as those of P. High Zn (10 mg kg^?1) decreased the biomass of both shoots and roots; this result may be ascribed to Zn toxicity. Phosphorus and Zn showed complicated interactions in uptake by plants within the ranges of P and Zn levels used. Cadmium in shoots decreased significantly with increasing Zn (P < 0.001) except at P addition of 10 mg kg^?1. In contrast, root Cd concentrations increased significantly except at Zn addition of 5 mg kg^?1 (P < 0.001). These results indicated that Zn might inhibit Cd translocation from roots to shoots. Cadmium concentrations increased in shoots (P < 0.001) but decreased in roots (P < 0.001) with increasing P supply. The interactions between Zn and P had a significant effect on Cd accumulation in both shoots (p = 0.002) and roots (P < 0.001).     

Zinc Biofortification in Sixty Groundnut Cultivars Through Foliar Application of Zinc Sulphate

A field experiment with 60 groundnut cultivars, in a calcareous soil having 1.20 mg kg^?1 available zinc (Zn), foliar application of 0.2% aqueous solution of zinc sulphate thrice at 40, 55 and 70 days at 500, 500 and 1000 L ha^?1, respectively, increased the number of pods, pod yield, shelling and 100 seed mass and seed zinc (Zn) content, significantly. The seeds Zn content in groundnut cultivars ranged 38–70 mg kg^?1 with an average of 48 mg kg^?1 without Zn and 58 mg kg^?1 with Zn. Foliar Zn application increased 22% Zn in seed. This increase was more than 10% in 48 out of 60 cultivars. The cultivars GG 7, GG 20, Tirupati 4, DH 8, JSP 19, TKG 19 A, CSMG 884 and S 206 showed > 50 mg kg^?1 Zn, > 10% increase in seed Zn with Zn application and > 250 g m^?2 pod yield.     

Effects of Urea Foliar Application on Grain Yield and Quality of Winter Wheat

The effects of urea foliar application rates at different growth stages of wheat on protein and yield of winter wheat were evaluated in a factorial experiment. Time of application and amounts of urea foliar application rates were the treatments. Urea was applied at four stages including tillering, jointing, anthesis, and grain filling, and urea foliar application rates were 22.5, 45, 67.5, and 90 kg ha^?1 (12.5, 25, 37.5, and 50% of total urea application). Our data demonstrated that urea application time had significant effects on grain weight, number of seeds per spike, plant height, and protein content. Furthermore, total dry weight, grain weight, harvest index, 1000-seed weight, plant height, and protein content were significantly affected by amounts of urea foliar application. The effects of time?×?rate of urea foliar application on grain yield, 1000-seed weight, and plant height were significant.     

黄淮麦区小麦籽粒锌含量差异原因与调控

小麦高产优质生产对保障我国粮食安全和人们营养健康有重要意义。通过实地调研和取样分析,研究了黄淮麦区276个田块的小麦籽粒锌含量与产量和产量构成、施肥和土壤养分、作物锌吸收利用等参数的关系。结果表明,黄淮麦区缺锌和非缺锌土壤的比例分别为42%和58%,两种土壤上的小麦籽粒锌含量分别介于16~52和17~58 mg·kg^-1,分别有7%和9%样本的籽粒锌达到推荐值40 mg·kg^-1。缺锌田块,籽粒锌含量与磷肥用量（r = -0.273,P < 0.01）、0~20 cm土壤有效磷（r= -0.283,P < 0.01）显著负相关,高低籽粒锌组的磷肥用量分别为73和137 kg·hm^-2,土壤有效磷分别为13和20 mg·kg^-1,有效锌分别为0.8和0.7 mg·kg^-1,但籽粒产量低于非缺锌土壤（7 204 和7 857 kg·hm^-2）。非缺锌田块,籽粒锌含量与磷肥用量显著负相关（r= -0.181,P < 0.05）,与0~20 cm（r= 0.236,P< 0.01）和20~40 cm（r= 0.183,P < 0.05）土壤有效锌显著正相关,高低锌组的磷肥用量分别为112和145 kg·hm^-2,0~20 cm的土壤有效磷分别为29和30 mg·kg^-1,有效锌分别为3.3和2.2 mg·kg^-1。因此,在缺锌土壤上,应首先解决土壤缺锌问题,将有效锌提升至临界值1.0 mg·kg^-1以上,非缺锌土壤有效锌保持在3.0 mg·kg^-1以上,同时适当减少磷肥用量和降低土壤有效磷水平,以减少磷对小麦锌吸收的负面影响,维持黄淮麦区小麦高产并改善籽粒锌营养。     

Within-Field Variability of Winter Wheat Yield and Grain Quality versus Soil Properties

Within-field variability in wheat grain yield and its quality always exists in production fields and depends, among other factors, mainly on various soil properties related to nutrients and water availability. The aim of the research was to examine the relationships between selected soil properties such as texture; pH; content of the available phosphorus (P), potassium (K), magnesium (Mg), and organic carbon; and winter wheat grain yield and quality under rainfed conditions. Six crop fields with winter wheat (Triticum aestivum, L.) in three sites located in different regions of Poland were examined during two seasons. The grain yield was mainly determined by the soil texture, and the majority of the chemical soil properties did not have a significant effect on grain yield. The grain quality traits were determined by the examined soil properties to a smaller degree than grain yield. The relationships were not consistent across sites and years.     

施氮量对2个粒色小麦产量及加工品质的影响

为探究施氮量对2个不同粒色小麦品种产量和加工品质的影响,采用裂区试验设计,以白粒小麦中麦8号和黑粒小麦漯珍1号为试验材料,测定2个品种的SPAD值、产量及产量构成因素和部分加工品质指标。结果表明,在同一施氮水平下,2个品种旗叶的SPAD值随时间推移呈先升高后降低的趋势,均在花后20 d和施氮量300 kg·hm~(-2)处理下有最大值,分别为57.52和63.55,增施氮肥可以有效缓解小麦旗叶叶绿素的降解,延长旗叶功能期。在120~300 kg·hm~(-2)的施氮量范围内,除中麦8号的穗粒数在施氮量300 kg·hm~(-2)处理下有最大值外,籽粒产量及产量构成因素随施氮量增加呈先增加后降低的趋势。随施氮量的增加,容重、硬度、出粉率和吸水率逐渐增加;蛋白质含量、沉降值、湿面筋含量、形成时间、稳定时间及粉质评价值呈先升高后降低趋势,最高值出现在施氮量240 kg·hm~(-2)的处理;漯珍1号的籽粒蛋白质含量、沉降值、湿面筋、吸水率、形成时间和粉质评价值均高于中麦8号,而容重、硬度、出粉率和稳定时间反之。2个品种在施氮量240 kg·hm~(-2)处理下既提高了产量又改善了部分加工品质。本研究结果为不同粒色小麦优质高产栽培提供了理论依据。     

追氮量对黑小麦品种(系)籽粒产量和品质的影响

为探究追氮量对不同黑小麦品种(系)籽粒产量和品质的影响,本研究采用大田裂区试验设计,主区为11个黑小麦品种(系),副区为追施氮量0(N0,对照)、34.5(N1)、51.8(N2)、69.0(N3)kg·hm²,于小麦灌浆期测定旗叶叶绿素含量(SPAD值),成熟期测定籽粒产量及产量构成要素、籽粒氮素含量和品质指标。结果表明,旗叶SPAD值在追氮处理下均增加,除B145-2、L10056、L10058的旗叶SPAD值在N1最高,其余8个品种(系)的旗叶SPAD值均随追氮量增加而升高。追施氮肥均有利于增加黑小麦产量,与N0相比,N1、N2和N3的产量增幅分别为15.2%~99.7%、17.5%~80.9%和0.7%~69.9%。11个品种(系)获得最高产量的适宜追氮量因品种而异,其中L10056、B120-2、运黑14207籽粒产量随追氮量增加而增加,B145-2、L10058籽粒产量在N2最高,其余6个品种(系)籽粒产量在N1最高。追氮量、品种及二者交互均对产量及构成因素存在极显著影响。追施氮肥能够提高多数黑小麦品种籽粒氮素含量,其中B145-2、L10058和运黑14207在N2最高,18鉴46、临黑131、冬黑1号、临黑187、2002-4、运黑161在N1最高。追氮量与籽粒产量、氮含量、蛋白含量呈正相关(相关性不显著),而产量与籽粒蛋白含量及多数品质指标存在极显著负相关关系。综合考虑黑小麦产量及品质的提高,追氮量在34.5~51.8 kg·hm²之间较为适宜。本研究结果可为黑小麦合理施用氮肥提供参考。     

追氮量对黑小麦品种(系)籽粒产量和品质的影响

为探究追氮量对不同黑小麦品种(系)籽粒产量和品质的影响,本研究采用大田裂区试验设计,主区为11个黑小麦品种(系),副区为追施氮量0(N0,对照)、34.5(N1)、51.8(N2)、69.0(N3)kg·hm²,于小麦灌浆期测定旗叶叶绿素含量(SPAD值),成熟期测定籽粒产量及产量构成要素、籽粒氮素含量和品质指标。结果表明,旗叶SPAD值在追氮处理下均增加,除B145-2、L10056、L10058的旗叶SPAD值在N1最高,其余8个品种(系)的旗叶SPAD值均随追氮量增加而升高。追施氮肥均有利于增加黑小麦产量,与N0相比,N1、N2和N3的产量增幅分别为15.2%~99.7%、17.5%~80.9%和0.7%~69.9%。11个品种(系)获得最高产量的适宜追氮量因品种而异,其中L10056、B120-2、运黑14207籽粒产量随追氮量增加而增加,B145-2、L10058籽粒产量在N2最高,其余6个品种(系)籽粒产量在N1最高。追氮量、品种及二者交互均对产量及构成因素存在极显著影响。追施氮肥能够提高多数黑小麦品种籽粒氮素含量,其中B145-2、L10058和运黑14207在N2最高,18鉴46、临黑131、冬黑1号、临黑187、2002-4、运黑161在N1最高。追氮量与籽粒产量、氮含量、蛋白含量呈正相关(相关性不显著),而产量与籽粒蛋白含量及多数品质指标存在极显著负相关关系。综合考虑黑小麦产量及品质的提高,追氮量在34.5~51.8 kg·hm²之间较为适宜。本研究结果可为黑小麦合理施用氮肥提供参考。     

Influence of Exogenous Application of Silicon and Potassium on Physiological Responses,Yield, and Yield Components of Salt-Stressed Wheat

To investigate the effect of exogenous application of silicon and potassium on some physiological responses, yield, and yield components of two wheat cultivars (Pishgam and Alvand) grown under salt-stress conditions, a field experiment was conducted at the Agricultural and Natural Resources Research Centre in East Azerbaijan, Iran, during 2012 and 2013 growing seasons. The experiment was arranged in factorial design based on randomized complete blocks design with three replications in each year. Wheat seeds were sown in saline soil (10 dS m^?1) and irrigated with saline water (4 dS m^?1). The plants were sprayed with silicon and potassium solutions at 0, 2, and 4 mM and 0, 100, 200, and 300 mM concentrations, respectively. The results demonstrated that silicon and potassium application improved antioxidant enzyme activity, chlorophyll content, photosynthesis rate, potassium uptake, yield, and yield components in both wheat cultivars. Although silicon and potassium had significant effects on all studied traits, there was a great interactive effect between them. When these two elements were applied on plants, the positive effect was more pronounced. Among all treatments, the most effective treatment was 4 mM silicon and 300 mM potassium. The greatest enzyme activity, chlorophyll content, photosynthesis rate, potassium uptake, yield, and yield components and the lowest proline, malondialdehyde, and sodium accumulations were observed in this treatment.     

Phosphorus Response and Fertilizer Recommendations for Wheat Grown on Nitisols in the Central Ethiopian Highlands

The provision of farmers with proper and balanced fertilizer recommendations is becoming increasingly important, for reasons of crop productivity, food security, and sustainability. Phosphorus (P) response trials with wheat were conducted on Nitisols at 14 sites in the central Ethiopian highlands during the 2010 and 2011 cropping seasons. The treatments, comprising six levels of P fertilizer (0, 10, 20, 30, 40, and 50 kg P ha^?1), were arranged in a randomized complete block design with three replicates. Based on a yield difference between the control and the P treatments, 90% of sites responded to P fertilizer. Application of P fertilizer increased wheat grain yield, up to 30% more than the control. Extractable soil P concentrations (Bray 2, 0–15 cm deep) 3 weeks after planting significantly responded to P fertilizer rate. The critical P concentration (for 90% relative yield) was 13.5 mg kg^?1. Most sites tested had Bray 2 P values <10 mg kg^?1. In the absence of a soil test, a recommendation of 40 kg P ha^?1, resulting in the best response overall, could be made for the first year of application. We also recommend that to prevent a potential loss of wheat yield, a maintenance application of at least 5–12 kg P ha^?1 be applied every year, irrespective of the calculated recommended rate, in order to replace P exported from the field in produce. Further field trials are required to determine interactions between P response and the effects of climate, soil properties, and other management practices.     

灌水量对不同小麦品种籽粒品质、产量及土壤硝态氮含量的影响

选用强筋小麦济麦20和中筋小麦泰山23两个品种，在大田条件下设置不灌水（0mm）、灌水180mm，240mm和300mm4个处理，研究了灌水量对籽粒品质和产量及土壤硝态氮含量的影响。结果表明，灌水180mm和240mm的处理比不灌水和灌水300mm的处理提高了强筋小麦济麦20的籽粒谷蛋白含量、谷蛋白含量／醇溶蛋白含量比值（谷／醇比值）、谷蛋白大聚合体（GMP）含量和湿面筋含量，延长了面团稳定时间，改善了籽粒品质；中筋小麦泰山23的不灌水处理的籽粒蛋白质含量高于灌水180mm，240mm和300mm的处理，但是GMP含量、湿面筋含量和面团稳定时间各处理间无显著差异。两品种的籽粒产量均以灌水240mm的处理最高，但泰山23灌水180mm的处理与灌水240mm的处理无显著差异。随灌水量增加，土壤中的硝态氮向深层土壤的淋溶增加。本试验条件下，综合考虑品质、产量和土壤中硝态氮的淋溶，济麦20和泰山23可供生产中参考的灌水量分别为180～240mm和180mm。