【作者】 唐锐；

【导师】 翟丙年；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2023， 硕士

【摘要】 水、氮是影响小麦生长发育的两大因子,随着水肥一体化技术在我国农业生产中的推广与应用,水、氮对我国小麦生产的调控作用更加直接与频繁,但当前小麦生产实践中仍缺乏科学合理的水肥一体化方案。灌溉施氮过量不仅降低了水氮利用效率,而且提高了生产投入成本,甚至造成资源浪费与环境污染。为了兼顾水氮利用效率、土壤肥力状况与作物生产高效,本文以陕西省关中平原喷灌冬小麦为研究对象,以探寻符合当地集约化生产的水肥一体化方案为目标,通过田间试验设置4个灌溉水平（W1:30,W2:60,W3:90,W4:120 mm）和4个施氮水平(N1:150,N2:187.5,N3:225,N4:262.5 kg·hm^-2),共计16个处理,研究了喷灌条件下水氮调控及其互作效应对冬小麦生长发育、产量及构成要素、氮素吸收转移、水氮利用效率、土壤肥力状况以及硝态氮残留的影响。主要研究结果如下:（1）春后灌溉与施氮可以显著促进冬小麦生长发育后期的干物质积累,自抽穗期到成熟期W4N3处理的干物质增长量最多为15012 kg·hm^-2。在成熟期,W2、W3、W4灌溉条件下小麦干物质积累量分别较W1灌溉提高1514、2240、2228 kg·hm^-2;N2、N3、N4施氮条件下小麦干物质积累量分别较N1施氮提高1288、2010、1514 kg·hm^-2。灌溉与施氮对小麦产量的影响具有明显的耦合效应,W3N2处理下小麦产量最高达9053 kg·hm^-2,较W1N1、W3N1处理分别增产27.9%、16.1%。（2）成熟期小麦籽粒氮素积累量随灌溉量、施氮量提高呈先增多后减少趋势,其中,W3N2处理籽粒氮素积累量最高为197 kg·hm^-2,较W1N1处理显著增长24.7%。在相同灌溉水平下,增加施氮量导致小麦氮素利用效率显著下降,其中氮肥偏生产力下降最显著,N4施氮较N1施氮下降34.5%-40.4%;相同施氮水平下,灌溉量增加导致水分利用效率降低,W4灌溉的水分利用效率较W1灌溉下降12%-15.9%。（3）提升施氮水平显著提高成熟期土壤硝态氮、铵态氮、全氮含量以及p H值,降低水溶性碳含量;提升灌溉水平显著提高土壤水溶性碳与全磷含量。过量施氮或灌水不足均导致0-200 cm土体的硝态氮残留增加,N4施氮条件下平均硝态氮残留量为199.3 kg·hm^-2;W1灌溉下的平均残留量为194.1 kg·hm^-2。水氮调控显著促进抽穗期至成熟期土壤微生物量碳、氮的增长,抑制微生物量磷的下降。成熟期微生物量碳、氮、磷分别在W3N3、W3N4、W4N4处理达到最大值,较W1N1处理分别提高20.5%、59.2%、52%。微生物量碳熵、氮熵、磷熵三者之间两两显著正相关,微生物量熵、土壤硝态氮与p H值显著影响土壤微生物量。（4）路径分析表明,吸收积累量对产量的直接调控作用最强,水氮投入对小麦产量的间接调控作用最强,二者是实现小麦增产的主要因素。不同水氮处理下土壤养分状况与产量的综合质量评价得出,W4N3处理的综合得分最高为1.38、其次为W3N2（1.27）、W3N3（1.14）、W3N4（1.07）、W2N3（0.94）、W4N4（0.58）、W2N4（0.55）,以上7个处理被聚合为一类,为最优处理集合。综上所述,灌溉施肥水平可以显著调控小麦的生长发育以及土壤养分状况,保障较高的干物质及氮素积累是实现小麦增产的主要因素。在关中地区喷灌条件下冬小麦生产中,推荐全生育期灌溉80-100 mm,配合施氮180-220 kg·hm^-2,可以实现水氮利用、土壤肥力与小麦生产的高效协同。更多还原

【Abstract】 Water and nitrogen are two major factors that affect the growth and development of wheat.With the promotion and application of integrated water and fertilizer technology in agricultural production in China,the regulatory effects of water and nitrogen on wheat production in China are more direct and frequent.However,there is still a lack of scientific and reasonable integrated water and fertilizer solutions in current wheat production practice.Excessive nitrogen application in irrigation not only reduces water and nitrogen utilization efficiency,but also increases production input costs,and even causes resource waste and environmental pollution.In order to give consideration to water and nitrogen use efficiency,soil fertility status and crop production efficiency,this paper takes winter wheat under sprinkler irrigation in the Guanzhong Plain of Shaanxi Province as the research object,with the goal of exploring a water and fertilizer integration scheme that conforms to local intensive production,through field experiments,four irrigation levels（W1:30 mm,W2:60 mm,W3:90 mm,W4:120 mm）and four nitrogen application levels(N1:150,N2:187.5,N3:225,N4:262.5 kg·hm^-2)were set up,A total of 16 treatments were used to study the effects of water and nitrogen regulation and interaction on winter wheat growth and development,yield and components,nitrogen absorption and transfer,water and nitrogen use efficiency,soil fertility status and nitrate nitrogen residue under sprinkler irrigation.The main research findings are as follows:（1）Irrigation and nitrogen application after spring can significantly promote the accumulation of dry matter in the later stage of winter wheat growth and development.The maximum increase in dry matter from heading stage to maturity stage under W4N3 treatment is 15012 kg·hm^-2.During the mature stage,the dry matter accumulation of wheat under W2,W3,and W4 irrigation conditions increased by 1514,2240,and 2228 kg·hm^-2 compared to W1 irrigation,respectively;The dry matter accumulation of wheat under N2,N3,and N4nitrogen application conditions increased by 1288,2010,and 1514 kg·hm^-2compared to N1nitrogen application,respectively.There is a significant coupling effect between irrigation and nitrogen application on wheat yield.Under W3N2 treatment,the wheat yield reaches a maximum of 9053 kg·hm^-2,which is 27.9%and 16.1%higher than that of W1N1 and W3N1treatments,respectively.（2）The nitrogen accumulation in wheat grains during the mature stage showed a trend of first increasing and then decreasing with the increase of irrigation and nitrogen application.Among them,the highest nitrogen accumulation in grains was 197 kg·hm^-2 in the W3N2treatment,which was significantly increased by 24.7%compared to the W1N1 treatment.Under the same irrigation level,increasing nitrogen application rate resulted in a significant decrease in nitrogen utilization efficiency of wheat,with the most significant decrease in nitrogen fertilizer productivity,with N4 nitrogen application decreasing by 34.5%-40.4%compared to N1 nitrogen application;Under the same nitrogen application level,an increase in irrigation amount leads to a decrease in water use efficiency.The water use efficiency of W4 irrigation decreases by 12%-15.9%compared to W1 irrigation.（3）Improving nitrogen application levels significantly increases the content of nitrate nitrogen,ammonium nitrogen,total nitrogen,and p H value in mature soil,while reducing the content of water-soluble carbon;Improving irrigation level significantly increases the content of water-soluble carbon and soil total phosphorus.Excessive nitrogen application or insufficient irrigation can lead to an increase in nitrate nitrogen residue in the 0-200 cm soil mass,with an average nitrate nitrogen residue of 199.3 kg·hm^-2 under N4 nitrogen application conditions;The average residual amount under W1 irrigation is 194.1 kg·hm^-2.Water and nitrogen regulation significantly promotes the growth of soil microbial biomass carbon and nitrogen from heading to maturity,and inhibits the decrease of microbial biomass phosphorus.During the mature stage,the microbial biomass of carbon,nitrogen,and phosphorus reached their maximum values in W3N3,W3N4,and W4N4 treatments,which were 20.5%,59.2%,and 52%higher than those in W1N1 treatment,respectively.There is a significant positive correlation between microbial biomass carbon entropy,nitrogen entropy,and phosphorus entropy.Microbial biomass entropy,soil nitrate nitrogen,and p H value significantly affect soil microbial biomass.（4）Path analysis shows that the direct regulation effect of absorption and accumulation on yield is the strongest,while the indirect regulation effect of water and nitrogen input on wheat yield is the strongest.Both are the main factors for achieving wheat yield increase.The comprehensive quality evaluation of soil nutrient status and yield under different water and nitrogen treatments showed that the W4N3 treatment had the highest comprehensive score of1.38,followed by W3N2（1.27）,W3N3（1.14）,W4N2（1.09）,W3N4（1.07）,W2N3（0.94）,and W4N4（0.58）.The above seven treatments were aggregated into one group,making them the optimal treatment set.To sum up,the level of irrigation and fertilization can significantly regulate the growth and development of wheat,as well as the soil nutrient status.Ensuring high dry matter and nitrogen accumulation is the main factor in achieving wheat yield increase.In the winter wheat production under sprinkler irrigation in Guanzhong area,it is recommended to irrigate 80-100mm in the whole growth period,and apply 180-220 kg·hm^-2 of nitrogen in combination,which can achieve efficient synergy of water and nitrogen utilization,soil fertility and wheat production.更多还原