【作者】 姜慧敏；

【导师】 刘更另； 杨俊诚；

【作者基本信息】 中国农业科学院 ， 土壤学， 2012， 博士

【摘要】 针对我国集约化设施蔬菜生产中氮素不合理投入导致资源浪费、土壤质量退化和环境污染风险增加等突出问题，以我国设施蔬菜生产典型区山东寿光为研究基地，通过实地调查、田间试验，研究了不同氮肥管理模式对不同棚龄设施菜地土壤肥力质量、环境质量和氮素利用的影响。采用灰关联度方法初步确定了氮肥优化管理模式，利用15N交叉双标记的田间微区实验探明了农民习惯施氮和氮肥优化管理模式下有机、无机氮素在植物-土壤体系中的去向。研究提出了山东寿光设施菜地合理的氮肥管理模式，同时为保持设施蔬菜优质高效生产和土壤可持续利用提供了理论和技术支持。主要研究结果如下：（1）在对寿光设施菜地的实地调查和已有资料分析的基础上，提出了当地农民习惯施肥量：化肥氮1000kg N/ha，有机肥氮1200kg N/ha。寿光集约化设施菜地农民习惯水肥管理下氮素的盈余结果表明，设施菜地土壤氮素损失情况十分严重。（2）设施菜地0-20cm耕层土壤肥力水平随种植年限的增加而增加，与农民习惯氮肥管理模式相比较，减施氮肥管理模式在耕层中能够保证较高的土壤肥力。随着氮肥施用量和种植年限的增加，耕层土壤中电导率含量显著增加（P<0.05），且土壤电导率与土壤硝态氮含量间存在显著的正相关关系。与农民习惯氮肥管理模式相比较，减施氮肥管理模式下土壤电导率均有降低，说明减施氮肥模式能够有效地抑制土壤盐渍化的形成。硝态氮是设施菜地无机氮残留的主要形式。低龄大棚硝态氮主要累积在0-20cm土层，随着氮肥的不断施入，高龄大棚中60-100cm土层均有较多的硝态氮累积。减施氮肥管理模式均能够降低土层硝态氮的积累，其中以50%农民习惯化肥氮（500kg N/ha）+秸秆+滴灌模式降低的土壤硝态氮累积最显著（P＜0.05）。（3）农民习惯氮肥管理模式下过量的氮肥投入没有显著提高作物的产量和品质，反而降低了氮肥农学效率、氮肥利用率和氮肥生理效率，产值、效益和产投比的下降；较农民习惯施氮量减少30%-50%能够保证番茄具有较高的产量和品质，有利于提高作物对氮素的吸收和利用，但是需要配合其他的措施效果更好。（4）灰关联度法结果表明，50%农民习惯化肥氮（500kg N/ha）+秸秆+滴灌的管理模式在番茄生产管理中的综合评价最好，农民习惯氮肥管理模式在设施生产中综合效益最低。15N双标记示踪试验结果表明，两个氮肥管理模式下作物对当季化肥氮的吸收和利用均显著高于对有机肥氮的吸收和利用（P＜0.05）；化肥氮主要以硝态氮的形式残留在土壤中，而有机肥氮主要以有机结合态氮的形态存在，土壤残留的氮均随土层深度的增加而降低；化肥氮的损失量和损失率均低于有机肥氮；氮肥优化模式能够显著提高化肥氮和有机肥氮的吸收和利用，显著降低化肥氮在土壤中的残留和氮肥在不同途径的损失量（P＜0.05），而对有效减少有机肥氮在土壤中的残留和损失方面相差不大。基于上述试验结果，综合考虑氮肥管理模式对设施菜地农学效应、肥力效应和环境效应影响，确定在寿光设施菜地的化肥氮投入量为500kg N/ha，灌溉方式为滴灌，并在设施菜地中添加一定量的秸秆调节土壤C/N比，有利于稳定土壤-蔬菜系统的氮素平衡，保证番茄产量和品质、改善土壤质量和降低化肥氮的表观损失，从可持续发展角度来看，具有更大的应用价值。更多还原

【Abstract】 Excessive nitrogen （N） fertilization input has resulted in deteriorated crop yield and quality, lowefficiency of N use, soil quality degeneration and serious environmental problems, etc. Field plot trailsthat aiming to resolve the problems were carried out in Guan Lu village （GL） and Dong Liu Ying village（DLY） of Shouguang, Shandong Province, the famous greenhouse vegetable production base in northernChina. Based on the results of the effects of different N fertilizer management models on soil quality,utilization and fate of N and the statistical analysis of Gray Relational Analysis, an optimum N fertilizermanagement model was selected. To understand the mechanism of N fertilizer recovery rates underfarmer’s common practices and optimum N fertilizer management model, the micro-plot experimentwith¹5N tracing technique was utilized to investigate the fate and utilization on chemical and organic Nfertilizer. The main findings were as follows:（1） Based on the statistical data of literatures and the farm’s survey in Shouguang, theconventional chemical and organic N were1000and1200kg/ha, respectively. N surplus was analyzedaccording to “black box method” under conventional N fertilizer model. The results showed N loss wasvery serious in greenhouse vegetable system.（2） Soil fertility such as total N, organic matter, available P and K were high in the0-20cmsurface layers and accumulation increasing with increasing length of period of vegetable production.There were no significant differences on soil urease and invertase abilities among different N fertilizermanagement models. Compared with conventional N fertilizer model, reducing30%-50%N fertilizercombined with some measurements could preserve soil fertility in greenhouse vegetable. Soil salinityoccured in the topsoil layer （0-20cm） of greenhouse, significantly increasing with increasing Nfertilizer application and length of period of vegetable production （P<0.05）. Soil electrical conductivity（EC） values were highly significantly and positively correlated with NO₃^--N concentrations, indicatingthat the excess NO₃^--N accumulations were an important factor contributing to soil salinity.Compared with conventional N fertilizer management model, soil EC value significantly lower in N5model （P<0.05）. The results indicated that reducing50%chemical N fertilizer combined with straw anddrip irrigation had significant impact on soil salinization inhibition. NO₃^--N accumulation was the mainsoil mineral N residue form. NO₃^--N accumulation in0-100cm soil profile was significantly increasedwith the increasing of N rate. NO₃^--N mainly accumulated in0-20cm soil depth in GL. Over-applied Nfertilizer under conventional N fertilizer management model resulted in more NO₃^--N accumulated in60-100cm soil profile in DLY. The average NO₃^--N accumulation amounts in0-100cm soil profileunder conventional N fertilizer management model were higher than other N fertilizer models.Reducing50%N fertilizer combined with straw and drip irrigation significantly decreased soil NO3–-Naccumulation.（3） The highest N fertilizer rate and irrigation （conventional N fertilizer model） not only lowered Nagronomic efficiency, N recovery and N physiologic efficiency, but also failed to improve tomato yieldand quality, thus reducing outputs and profit for farmers and wasting N fertilizer. High crop yields, quality and N use efficiency could be achieved with reducing30%-50%N fertilizer application, butsome measurements should be combined with it.（4） Gray Relational Analysis indicated that the best comprehensive evaluation was achieved by50%reduction of the conventional N chemical fertilizer input combined with adjustment of the C/Nratio and water–fertilizer coupling （N5model） and the worst comprehensive evaluation wasconventional N fertilizer model （N1）. So N5model was selected as the optimum N fertilizermanagement model. The micro-plot experiment with¹5N tracing technique showed that¹5N recoveryderived from chemical N fertilizer was significantly higher than¹5N recovery derived organic Nfertilizer under N1and N5models. NO₃^--N was the main chemical N residue form, but organic-boundwas the main organic N residue form.¹5N loss derived from chemical N fertilizer was significantlyhigher than¹5N recovery derived organic N fertilizer. Increasing N rate decreased crop recovery butincreased soil N recovery. Compared with N1model,¹5N recovery under optimizing N application wassignificantly improved, whatever¹5N derived from chemical or organic N fertilizer （P<0.05）. Otherwise,¹5N residue and loss derived from chemical N fertilizer were significantly decreased under N5model（P<0.05）. A great deal of manure was used for the high benefit of greenhouse vegetable cropping system,which led to more organic N residue and loss. There was no significantly difference between N1and N5model.The present study showed that environmental protection and high crop yields could be achievedwith a50%reduction of the conventional N chemical fertilizer input combined with adjustment of theC/N ratio and fertigation. These combined approaches represent a practical approach for reducingexcess N input while maintaining the sustainability of greenhouse-based intensive vegetable systems.更多还原