【作者】 陆欣春；

【导师】 田霄鸿；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2012， 博士

【摘要】 我国小麦主产区主要位于北方石灰性土壤地带，其土壤有效Zn含量多处于潜在缺锌水平（DTPA-Zn含量为0.5¹.0mg·kg-1），生产的小麦籽粒Zn含量较低（平均含量26.8mg·kg-1），难以满足以其为主食人群对锌的营养需求，从而众多人口由于缺锌导致严重健康问题。施用锌肥是提高小麦籽粒Zn含量的最直接有效途径，而前期在石灰性土壤上田间试验结果表明，土施低量锌肥对小麦籽粒Zn含量提高幅度有限，不能满足人体Zn营养需求，那么增加施锌量是否能继续增加小麦籽粒Zn含量？同时石灰性土壤对外源锌肥固定是限制锌肥肥效的主要原因，为此监测锌肥施入潜在缺锌石灰性土壤后各形态Zn含量动态变化，揭示土壤对锌肥的固定机制，对指导潜在缺锌石灰性土壤地区施用锌肥提高小麦籽粒Zn含量具有重要科学意义。且在实际生产中氮磷肥的大量施用对锌肥肥效亦有一定影响，尤其是磷锌间的拮抗作用早已成为被关注热点问题，但关于土壤中二者关系研究较少，尤其是磷锌配施对土壤中不同形态Zn含量的影响还未见报道，因此本研究在潜在缺锌石灰性土壤上分别进行了不同施锌量、氮锌配施、磷锌配施3个冬小麦田间定位试验，得到以下主要结果：1.不同施锌量(0、7.5、15、30、45kg Zn·hm^-2)对小麦Zn营养品质影响的两季冬小麦田间定位试验。结果表明：土施锌肥对小麦籽粒Zn含量提高有限，增幅仅为11.4³3.2%，锌肥当季利用率仅为0.14⁰.98%，且以高施锌量(45kg·hm^-2)处理Zn肥利用率最低，而锌肥后效对第二季小麦籽粒Zn含量未有显著增加；两季小麦地上部锌携出总量仅占施锌量的0.13¹.29%。不同施锌量对小麦籽粒植酸含量及[植酸]/[Zn2+]摩尔比影响均不显著。可见，在潜在缺锌石灰性土壤上增加施锌量不能继续增加小麦籽粒Zn含量，反而进一步降低了Zn肥利用率。2.氮锌配施(施氮量分别为0、105kg·hm^-2，施锌量分别为0、6.8kg·hm^-2，完全方案)对10个小麦品种Zn营养品质影响的两季冬小麦田间定位试验。结果表明：施锌肥对小麦籽粒Zn含量的影响因不同品种而异，单施锌肥仅增加了西杂1号、武农148、郑麦9023籽粒Zn含量，氮锌配施增加了除小偃22外其余9种供试小麦品种籽粒Zn含量，增幅为7.3-54.7%。单施锌肥对小麦地上部Zn累积量增加不明显，单施氮肥可显著增加小麦地上部Zn吸收，但其主要累积在小麦茎叶部，氮锌配施显著增加小麦地上部Zn累积量，两季分别增加了6.5%、29.8%。氮锌配施处理比单施锌肥显著增加了Zn肥利用率，单施锌肥和氮锌配施处理两季小麦地上部携出Zn总量分别占施锌量0.25%、1.50%。可见，潜在缺锌石灰性土壤上，在施氮肥基础上施锌肥对小麦籽粒Zn含量提高效果更好。3.磷锌配施(施P2O5量分别为0、50、100、150、200kg·hm^-2，施Zn量为0、7kg·hm^-2，完全方案)对小麦Zn营养品质影响的两季冬小麦田间定位试验。结果表明：低磷配施锌(P₅₀Zn₇)使两季小麦籽粒Zn含量比对照（P0Zn0）分别增加37.7%、8.8%，高磷配施锌(P₂₀₀Zn₇)反而使两季小麦籽粒Zn含量分别降低37.6%、17.0%；小麦籽粒植酸含量、[植酸]/[Zn²⁺]摩尔比均随施磷量增加而增加，磷锌配施的[植酸]/[Zn2+]摩尔比低于单施等量磷肥。可见，在潜在缺锌石灰性土壤上，高磷配施锌肥显著降低了小麦籽粒Zn生物有效性，为此在该地区施磷量不能高于100kg·hm^-2。4.土施锌肥(7.5⁴5kg·hm^-2)及磷锌配施均增加了小麦籽粒微量元素（Zn、Fe、Cu、Mn）总累积量，不同施锌量对Zn、Fe、Cu、Mn的分配比例影响较小，而磷锌配施时，随着施磷量的增加，Zn的吸收比例逐渐降低，Fe的吸收比例增加，造成小麦籽粒微量元素吸收不平衡。在不同试验条件下，小麦籽粒植酸含量与Zn、Fe、Cu、Mn间相关关系不一致，从而同时提高Zn、Fe、Cu、Mn微量元素含量和降低植酸含量而提高微量元素生物有效性较为困难。5.监测不同用量Zn肥(7.5⁴5kg·hm^-2)施入潜在缺锌土壤后DTPA-Zn含量变化结果表明，施锌可显著增加土壤DTPA-Zn含量，且随施锌量增加DTPA-Zn含量逐渐增加，锌肥施入土壤后7d，DTPA-Zn含量增加幅度为267⁵29%；到639d时，增加幅度为68¹37%，可见随时间推移土壤DTPA-Zn含量虽有所降低，但在两季小麦生育期内仍能维持较高水平（＞1.0mg·kg-1）。氮锌配施及磷锌配施试验结果表明，氮锌配施及磷锌配施对土壤DTPA-Zn含量增加幅度均低于单施锌肥处理，尤其磷锌配施条件下，DTPA-Zn含量随施磷量增加而逐渐降低。6.石灰性土壤中锌主要以矿物态（Min-Zn）存在，占全锌91.5⁹7.6%，其次为松结有机态锌（Wbo-Zn，1.34⁵.53%）、碳酸盐结合态锌（Carb-Zn0.47¹.55%）。相关分析、通径分析及主成分分析结果表明，土壤中交换态Zn（Ex-Zn）和Wbo-Zn对有效锌贡献最大，Carb-Zn亦间接影响土壤有效锌含量。小麦籽粒Zn含量与土壤中Ex-Zn、Wbo-Zn含量呈显著正相关关系，石灰性土壤中Wbo-Zn和Carb-Zn含量占有较为可观的比例，因此增加这两种形态储备容量是调节和控制土壤锌营养状况的重要措施。7.监测不同量锌肥(7.5⁴5kg·hm^-2)施入石灰性土壤后不同形态Zn含量动态变化结果表明，锌肥施入土壤初期（7d）主要增加了Wbo-Zn和Carb-Zn，两者增加量分别占施Zn量的63.4⁸4.0%和6.5¹0.3%；其后Wbo-Zn含量逐渐降低，到两季小麦收获后（231d、639d），施入锌肥的42.4⁶9.0%和62.0⁷8.1%已转化为无效的Min-Zn。氮锌配施及磷锌配施结果表明，氮锌交互作用对不同形态Zn含量影响不显著；磷锌交互作用对Wbo-Zn和Crab-Zn含量有影响显著，低磷配施锌(P0Zn7、P₅₀Zn₇)可使土壤Wbo-Zn含量分别增加4.0、4.4倍，对其他形态Zn含量无显著增加，高磷锌配施(P150Zn7、P₂₀₀Zn₇)对土壤Wbo-Zn和Crab-Zn影响均有负交互效应。基于以上3个田间试验结果可以得出以下主要结论：（1）在潜在缺锌土壤上，土施锌肥可以显著增加土壤DTPA-Zn含量，且能维持两季小麦生育期，但对小麦籽粒Zn含量提高幅度有限，锌肥利用率极低，氮锌配施比单施锌肥提高锌肥利用率。（2）高磷配锌降低土壤中有效性较高形态Zn（Wbo-Zn和Carb-Zn）含量，显著降低籽粒Zn生物有效性，因此在该地区磷锌配施时施磷量应低于100kg·hm^-2。（3）土壤中Ex-Zn、Wbo-Zn含量对有效锌贡献最大，与小麦籽粒Zn含量呈显著正相关。（4）锌肥施入土壤最初主要增加有效性较高的形态Zn含量，其后逐渐向无效态Zn（Min-Zn）转化，到小麦收获后一大部分转化为矿物态。综上在潜在缺锌石灰性土壤地区控制氮磷肥施用量对施锌效果至关重要，调节和控制土壤Wbo-Zn含量对提高小麦籽粒Zn含量解决人体Zn营养健康问题具有重要意义。更多还原

【Abstract】 In China, wheat is mainly grown on calcareous soils, of which DTPA-Zn is potentiallydeficient, being0.5-1.0mg·kg-1. Wheat grain Zn concentration is relativey low, averagely26.8mg·kg-1, which leading to Zn deficiency in human beings. Zinc fertilization is the mostdirect and efficient method to solve Zn deficiency. However, results from the previous fieldexperiments on calcareous soil showed that, Zn fertilization to soil with a low level had a littleeffect on increasing grain Zn concentration and then should grain Zn concentration beingincreased with the increasing level of Zn fertilizer? Meanwhile, Zn fixation in calcareous soilis the main inhibitory factor for low Zn effectiveness. How to increase grain Zn concentrationby Zn fertilization on potentially Zn-deficient soil, it is very important to research thedynamic changes of Zn fractions and Zn fixation on potentially Zn-deficient soil after Znfertilization to soil. Meanwhile, in practical producation, nitrogen and phosphorus also affecton Zn fertilizer effectiveness and the antagonist effect between P and Zn becomes a hot topic.However, the interaction between P and Zn in soil and the information of combined P with Znfertilization on Zn fraction was little. Therefore, three field location experiments onpotentially Zn-deficient soil were conducted to study the effects of Zn fertilization withdifferent levels, combined N and Zn fertilization and combined P and Zn fertilization on grainZn nutritional quality of winter wheat and Zn fractions in soil. The main results were asfollows.1. The effectiveness of Zn application to a potentially Zn-deficient calcareous soil wasmeasured using two winter wheat cultivars and five Zn fertilizer rates （0,7.5,15,30,45kg Znha-1）. The results showed that Zn fertilizer increased grain Zn concentration in2008-2009by11.4to33.2%. The apparent Zn utilization efficiency was between0.14and0.98%with thelowest Zn effectiveness in45kg Zn ha-1treatment. The after effect of Zn had no significanteffect on grain Zn concentration in2009-2010. The Zn uptake in shoots were0.13-1.29%inthe levels of Zn fertilizer in the two cropping. There was no significant effect of Znfertilization on grain phytic acid （PA） content and the PA: Zn molar ratio. Therefore, grain Znconcentration was not increased with the increasing Zn fertilizer levels and the effectiveness of Zn was also relatively reduced.2. A two-year experiment was conducted to investigate the effects of combined N-Znfertilizers on growth and Zn accumulation of10varieties of winter wheat. Results showedthat the effect of single Zn fertilizer application on yield and grain Zn concentration weresignificantly different among various varieties of winter wheat. Single Zn fertilizerapplication increased grain Zn concentrations of Xiza1, Wunong148, and Zhengmai9023.Combined N-Zn fertilizer increased grain Zn concentration of9varieties of wheat exceptXiaoyan22and the increment was7.3%-54.7%. There was no significant effect of single Znfertilizer application on Zn uptake. While single N fertilizer supply significantly enhancedshoot Zn uptake which primarily accumulated in wheat stem and leaf. Combined N-Znfertilizer significantly increased Zn uptake in wheat shoots, by6.5%and29.8%in the twoyears experiment. Combined N-Zn fertilizers significantly increased Zn fertilizereffectiveness compared to single Zn fertilizer application. The Zn uptakes in shoots were0.25%and1.5%of the levels of Zn fertilizer in the single Zn fertilizer application and theapplication of N and Zn fertilization. Therefore, the application of N and Zn fertilization is asensible method to increase grain Zn concentration on potentially Zn-deficient soil.3. A two-year field experiment was conducted to investigate the effects of combinedapplication of Zn and phosphorus fertilizers on Zn nutritional quality of winter wheat. Resultsshowed the application of50kg P₂O₅ha-1combined with Zn fertilizer （P50Zn7） increasedgrain Zn concentrations by37.7%in2006-2007and8.8%in2007-2008compared to theP0Zn0treatment. However, the P₂₀₀Zn₇treatment reduced grain Zn concentrations by37.6%in2006-2007and17.0%in2007-2008compared to the control （P₀Zn₀）. The PA concentrationand the PA: Zn molar ratio in wheat grain increased as P fertilizer application rate increased,regardless of the Zn fertilizer application rate. Meanwhile, the PA: Zn molar ratio wasrelatively lower in combined P with Zn fertilization compared to single P fertilization. Inconclusion, on potentially Zn-deficient calcareous soil, combined P with Zn fertilizationreduced grain Zn nutritional quality and P fertilizer application rates used in this study shouldbe <100kg P2O5ha-1to ensure the effectiveness of the Zn fertilizer.4. Zinc fertilization with the extent of7.5-45kg·ha-1and combined P-Zn fertilizerincreased the accumulation of grain micronutrients, such as Zn, Fe, Cu and Mn. However, theeffect of Zn fertilization on the distribution of Zn, Fe, Cu and Mn was little. The uptake of Znwas gradually reduced and Fe was increased with P levels increased in the combined P and Znfertilization treatment. Therefore, the balance of micronutrient uptake in grain of wheat wasbroken. Under different experimental conditions, the interaction between phytic acid and Zn,Fe, Cu, Mn was also different. Therefore, it is a big work to increase Zn, Fe, Cu, Mn concentration and at the same time to reduce phytic acid content.5. A two-year field experiment was conducted to study the effect of Zn fertilizerapplication on soil DTPA-Zn. Results showed that soil DTPA-Zn content was significantlyincreased with Zn levels increasing. After7d of Zn fertilizer application to soil, soilDTPA-Zn increased by267-529%, after639d, the extent was68-137%. Therefore, with timeelapsing, soil DTPA-Zn content was relatively reduced and in the two cropping, the soilDTPA-Zn was also higher than1.0mg·kg-1. The results in combined N with Zn fertilizationand combined P with Zn fertilization, these two application methods relatively had a littleeffect on reduced soil DTPA-Zn concent compared to single Zn fertilizer application.Especially in the combined P with Zn fertilization, the content of soil DTPA-Zn was graduallyreduced with P levels increasing in soil.6. In the soil Zn appeared mainly in the following fractions, mineral bonded Zn （Min-Zn）accounted for91.5%-97.6%of total Zn, Zinc weakly bound to organic matter （Wbo-Zn）accounted for1.34%-5.53%of total Zn and carbonate bonded Zn （Carb-Zn） accounted for0.47%-1.55%of total Zn. The analysis of path analysis and principal component showed thatthe exchangeable Zn （Ex-Zn）, the Wbo-Zn, the Carb-Zn could indicate the availability Zn insoils in various degrees, respectively. Zinc congcentration of wheat grain showed a strongpositive correlation with Ex-Zn and Wbo-Zn. Carbonate bounded Zn and Wbo-Zn accountedfor most parts of total Zn in calcareous soil. To stimulate and control the Zn nutrient conditionin calcareous soil, it is an important measure to increase the content of the Carb-Zn and theWbo-Zn in soil.7. A two-year field experiment was conducted to study the effect of Zn fertilizerapplication on soil Zn fractions. Results showed that, within one week of Zn fertilizerapplication, soil Wbo-Zn and Carb-Zn content was significantly increased by amountsequivalent to63.4-84.0%and6.5-10.3%of the fertilizer Zn application, respectively. TheWbo-Zn fraction decreased gradually over time. Calculations indicated that42.4-69.0%and62.0-78.1%of the Zn fertilizer was mineral bound after231d and639d, respectively. In thecombined N-Zn fertilization and combined P-Zn fertilization treatments, the interactionbetween N-Zn had no significant effect on Zn fractions; however, P0Zn7and P50Zn7treatments significantly increased soil Wbo-Zn content by4.0and4.4folds, respectively. Onthe other hand, P₁₅₀Zn₇and P₂₀₀Zn₇treatments significantly reduced soil Wbo-Zn andCarb-Zn content.Based on these results of the three field experiments, conclusions can be made:（1） Onpotentially Zn-deficient soil, Zn fertilization to soil significantly can increase soil DTPA-Zncontent within two cropping; however, the effect of Zn fertilizer on grain Zn concentration is relatively little. Respect to Zn effectiveness, combined N-Zn fertilization has a higher Zneffectiveness compared to single Zn fertilization.（2） High P levels combined with Znfertilization reduces soil Wbo-Zn, Carb-Zn content and grain Zn bioavailability. Therefore, onpotentially Zn-deficient soil, P fertilizer application rates used should be <100kg P2O5ha-1.（3） The Ex-Zn, the Wbo-Zn, the Carb-Zn could indicate the availability Zn in soils in variousdegrees, respectively. Meanwhile, these two Zn fractions significantly are positively relatedwith grain Zn concentration.（4） Zinc fertilizer application to soil is firstly transformed intomore effective Zn fractions and then gradually transforms into Min-Zn. After wheat harvest, alarge part of Zn fertilizer can be transformed into Min-Zn. Therefore, on potentiallyZn-deficient soil, sensible N and P application rate could increase Zn fertilizer effectivenessand to solve Zn deficiency in human, it is possible to increase grain Zn concentration byincreasing soil Wbo-Zn content.更多还原