【作者】 高晓宁；

【导师】 韩晓日；

【作者基本信息】 沈阳农业大学 ， 植物营养学， 2009， 博士

【摘要】 土壤氮素是土壤肥力的重要组成部分和作物氮素营养的主要来源。多数土壤氮素不能满足作物的生长需求,要靠施肥来予以补充和调节。但盲目、不合理的施用肥料,不仅造成肥料的大量浪费、经济效益下降,还会带来一系列的环境问题。了解土壤的供氮能力,合理施肥则是提高氮肥利用率、减少环境污染、提高作物产量和品质的基本途径。本文从当前生产实际出发,结合沈阳农业大学棕壤长期定位试验,深入系统地研究经过29年长期轮作施肥,不同施肥处理对棕壤各形态氮素含量分布特征、有机氮矿化特征以及土壤供氮能力的影响,探讨长期轮作施肥条件下棕壤氮素的演变规律和供氮机理,为棕壤氮素养分资源的高效利用提供理论依据。主要研究结果如下:1.经过29年长期不同施肥,耕层（0～20 cm）土壤有机质、全氮、碱解氮、无机态氮（硝态氮、交换性铵、固定态铵）和微生物量氮含量变化明显。各指标总的变化趋势为高量有机肥区＞低量有机肥区＞化肥区＞无肥区,其中高量有机肥和化肥配合施用效果最好。土壤有机质、全氮、碱解氮、无机态氮含量的剖面分布规律均为随土层的加深逐渐降低,而固定态铵的剖面分布则呈相反趋势。2.长期施肥能明显影响耕层土壤有机氮各组分的含量,尤对氨基酸态氮影响最为显著。总的分布趋势为氨基酸态氮＞非酸解态氮＞酸解氨态氮＞酸解未知态氮＞氨基糖态氮。其中酸解有机氮各组分含量随土层的加深而降低,各层次变化规律为有机无机肥配施处理＞单施有机肥处理＞单施化肥处理和CK处理,而非酸解态氮在各土层中则表现出无序性。3.在两个轮作周期中,土壤各氮素指标的含量均表现为玉米年份＞大豆年份。4.一级动力学方程（One pool模型）能很好地描述棕壤（0～60 cm土层）有机氮的矿化过程,且由One pool模型拟合得出的矿化参数能够表达土壤有机氮的矿化特征。5.长期施肥能显著增加耕层（0～20 cm）土壤氮素矿化势值。其变化规律为高量有机肥区＞低量有机肥区＞化肥区＞CK＞试验前（1979年）,以高量有机肥配施化肥的效果最好,土壤供氮潜能最大。不同施肥处理土壤氮矿化势随土层的加深而骤减,且各土层间差异显著。6.土壤氮矿化势（N₀）与土壤有机氮组分含量之间关系十分密切,其中以氨基酸态氮对土壤氮矿化势的直接贡献最大,其它有机氮组分则表现为通过氨基酸态氮的间接贡献。此外,土壤全氮也是影响土壤氮素矿化势的重要因素。7.土壤中各氮素指标与作物吸氮量、产量之间均达1%极显著水平,说明土壤中各形态氮在评价土壤供氮水平上均表现出一定的作用。其中以土壤氮素矿化势、可矿化氮、碱解氮三个指标能更好地评价土壤的供氮水平。8.土壤供氮量的大小顺序为高量有机肥区＞低量有机肥区＞化肥区＞CK,以高量有机肥配施化肥的效果最好。且呈上高下低的特点,即随土层深度的增加而迅速降低。耕层（0～20 cm）土壤供氮能力较强,且深层土壤的供氮能力也不容忽视。总之,长期有机无机肥配施,尤其是高量有机肥配施化肥处理,是维持土壤肥力最优的施肥方式。它可以显著提高土壤各形态氮素含量,进而影响了土壤氮素矿化势,达到改善土壤供氮能力的目的。因此,农业生产中在重视有机物料投入的同时,还应注意其与无机肥料的搭配使用。本文首次对长期定位试验棕壤的供氮特性进行了全面系统地研究,其结果丰富了我国土壤氮素的研究,对于科学合理地制定施肥方案、保障环境及农产品安全具有特殊重要的意义。更多还原

【Abstract】 The soil nitrogen is the important component of soil fertility and the main source of crop’s nitrogen nutrition. Most soil nitrogen cannot meet the crop growth needs, it depends on fertilization to complement and adjust. But the unreasonable use of fertilizer not only cause the vast waste and the decline of economic benefit but also bring a series of environmental problems. The basic approach of improving the nitrogen use efficiency, decreasing environmental pollution and raising crop’s yield is the understanding of the supplying nitrogen capacity and reasonable fertilization. According to the current actual situation, different fertilization treatments were used in a long-term fertilizer location experiment of Shenyang Agricultural University. After 29 years of long-term rotation and fertilization, the effect of different fertilization treatments on the distribution of N content, the mineralization of organic N and soil N supplying capacity were studied; The developing law and the supplying mechanism of soil N were discussed under long-term rotation and fertilization. They provide a theoretical basis for the utilization of N nutrient resource in brown soil. The main results as follows:1. After 29 years of long-term fertilization, the concentration of organic matter, total N, alkali hydrolyze N, inorganic N （ NO₃^--N, exchangeable NH₄⁺-N, fixed ammonium ） and SMBN in topsoil （ 0～20 cm） differed significantly at P<0.01. The general trend of soil N indexes was high level of organic manure treatment >low level of organic manure treatment > fertilizer treatment > control, expecially applying the higher level organic manure and inorganic fertilizer has the best effect. With the soil layers deeper, the concentration of soil organic matter, total N, alkali hydrolyze N, inorganic N reduced gradually, but the distribution of soil fixed ammonium was contrary trend.2. Long-term fertilization could increase the contents of soil organic N forms, especially the content of amino acid N. The general trend of organic N forms was amino acid N >non-hydrolysable N > ammonia N > hydrolysable unidentified N > amino sugar N. The distributions of acid hydrolysable organic N forms decreased with layers’ depth. The basic rule was organic-inorganic fertilizer treatment > single organic manure fertilizer treatment > single inorganic fertilizer treatment and the control. Non-hydrolysable N in each soil layers appeared out-of-order.3. In two rotation cycles, the concentration of each soil nitrogen indexes always showed the corn year >the soybean year.4. First-order kinetic equation （One pool model） could preferably described the mineralized process of brown soil （ 0～60 cm soil layer） organic N, and the parameters which were fitted by one pool model expressed the mineralization characteristics of soil organic N.5. Long-term fertilization could significantly increase the N mineralization potential of topsoil. The trend of soil N mineralization potential was high level of organic manure treatment >low level of organic manure treatment >fertilizer treatment >control >soil before the trial, expecially applying the higher level organic manure and inorganic fertilizer had the best effect and the biggest capacity on N supplying. With the soil layers deeper, the concentration of soil N mineralization potential had a sudden decrease and the different soil layers differed significantly.6. Soil N mineralization potential was correlated with soil organic N forms intimately. Amino acid N had the biggest direct contribution to N mineralization potential, and other components made indirect contribution through amino acid N. In addition, soil total N was also an important effect factor for soil N mineralization potential.7. Every soil N indexes were significantly correlated with crop yield and sorption contents of crop at P<0.01. It indicated that soil N forms had certain effects on assessing the N supplying level, especially N mineralization potential, mineralized N, alkali hydrolyze N.8. The sequence of soil N supplying amount was high level of organic manure treatment >low level of organic manure treatment > fertilizer treatment >control,expecially applying the higher level organic manure and inorganic fertilizer had the best effect. With the soil layers deeper, the amount of soil N supplying dropped fast. The topsoil had the stronger N supplying capacity, and that of the subsoil should not be ignored.In short, long-term fertilization of organic and inorganic, expecially applying the higher level organic manure and inorganic fertilizer, is considered the best way for maintaining the soil fertility. It can significantly improve the concentration of soil N forms, which affects soil N mineralization potential, in order to improve the capacity of soil N supplying. Therefore, we should attach importance to applying organic manure in agricultural production and pay attention to the combination of organic manure and inorganic fertilizer.It is the first time to study roundly N supplying characteristics of brown soil under long-term location experiment. The results enrich the theoretical study of soil N, and have great significance for forming fertilization programs, protecting environment and products safety.更多还原