【作者】 武其甫；

【导师】 武雪萍；

【作者基本信息】 中国农业科学院 ， 农业水资源利用， 2011， 硕士

【摘要】 当前我国蔬菜生产中普遍存在大水漫灌和过量施肥现象,不合理的水氮管理导致氮肥浪费严重、环境污染问题日益突出,土壤退化、蔬菜产量和品质下降成为限制蔬菜生产可持续发展的瓶颈。针对以上问题,在河北省辛集市马庄农场保护地大棚内设置小区试验,系统研究了不同灌溉、施氮量下保护地秋冬茬番茄季土壤N₂O排放损失量、氨挥发损失量、土壤氮素残留累积和损失规律及不同水氮管理对番茄产量和品质的影响。在本试验条件下,取得以下研究结论:1.节水灌溉、减施氮25%处理组合与传统水氮处理相比,显著降低了保护地土壤N₂O排放损失量。番茄整个生长期各处理N₂O排放损失量分别为W₁N₉₀₀ （5.304 kg/hm²）> W₂N₉₀₀ （4.913 kg/hm²）>> W₁N₆₇₅ （3.616 kg/hm²）>> W₂N₆₇₅ （2.901 kg/hm²）>> W₁ N₀ （0.563 kg/hm²） > W₂ N₀ （0.511 kg/hm²）。在传统灌溉量下,减施氮25%的处理N₂O排放损失量比传统施氮处理降低31.8%;节水灌溉量下,减施氮25%比传统施氮处理降低40.9%,处理间差异均达到显著水平;在减施氮25%的条件下,节水灌溉的处理相比传统灌溉也显著降低了N₂O排放损失量（降低19.7%）。由此可见,合理减少施氮量和灌溉量是降低保护地菜地N₂O排放损失量的有效途径。温度对保护地N₂O排放通量有明显的影响,在温度较高的8¹0月份,减少施氮量可以显著降低N₂O排放损失量,而在11¹2月份,不同施氮量间差异不显著。研究还表明,N₂O排放通量与土壤中硝态氮含量呈极显著正相关,出现的排放峰值一般在灌溉施肥后3⁵ d。施入蔬菜保护地土壤的氮肥有0.35% 0.53%以N₂O排放损失。2.与农民习惯施氮相比,减量施氮可以显著减少氨挥发损失量。本研究条件下番茄整个生长期各处理氨挥发损失总量的大小顺序为W₂N₉₀₀ （21.362 kg/hm²）> W₁N₉₀₀ （20.878 kg/hm²） >> W₂N₆₇₅ （17.632 kg/hm²） > W₁N₆₇₅ （17.466 kg/hm²） >> W1N0 (6.591 kg/hm² > W₂ N₀ （6.390 kg/hm²）。在2个灌溉水平下,减施氮25%处理分别比习惯施氮量处理降低氨挥发损失量17.5%和16.3%。相同施氮量下的不同灌溉量处理间氨挥发损失量无显著差异。温度和土壤pH是影响氨挥发的主要环境因素,施用尿素后土壤pH快速上升是土壤氨挥发峰值主要出现在施肥后1³ d的原因之一,而且温度较高的时期氨挥发强度更高。施入土壤中的氮素有1.59% 1.68%经氨挥发损失。3.番茄收获后施氮处理土壤0⁴0 cm土体累积了较高的的无机氮（239.7⁴26.5 kg/hm²）,占0¹00 cm土体总残留量的48.4%⁵2.5%,而相同施氮量下,节水灌溉处理的无机氮残留量显著高于传统灌溉处理,降低了氮素淋失出根层的风险。2个灌溉水平下,根层土壤氮素表观矿化量分别为183.9和211.1 kg/hm²。增施氮肥并没有显著提高番茄植株氮素吸收量,施氮处理氮素表观利用率为13.6%²1.6%。传统施氮量处理当季表观氮素损失率为59.0%⁶2.4%,而节水灌溉下、减施氮25%处理表观损失率为44.0%,显著低于其他施氮处理。4.本研究条件下施用氮肥没有显著增产,在2个灌溉水平下,减施氮25%的处理要比传统施氮量的处理产量提高5.6%和7.3%。不施氮肥虽然不会降低产量,但番茄果实品质有所下降,合理的水氮运筹才能保证高产,提高品质。综上所述,本地区保护地番茄生产中农户传统施氮量过高,有很大的减施氮空间。减量施氮不仅避免了减产,还提高了果实品质,降低了氮肥由于N₂O排放和氨挥发的损失量,也减少了表层土壤氮素积累和淋失。节水灌溉不仅不会影响产量,还在一定程度上提高蔬菜品质,减少氮素向深层的淋溶。在本试验条件下,节水灌溉、减施氮25%的处理(W₂N₆₇₅)是最佳水氮组合,相比当地习惯水氮处理(W₁N₉₀₀),可以减少N₂O排放损失45.3%,减少氨挥发损失15.5%,减少氮素表观损失率25.4%,提高根层氮素残留率72.9%。综合考虑,秋冬茬番茄经历前期高温、中期适温、后期低温的温光环境特点,前期番茄氮素需求量小,而且土壤温度和水分条件好,氮素矿化量较高,加之前茬作物的氮素残留,建议该地区建立基于土壤氮素供应、施肥供应和番茄氮素需求规律相协调的“前轻后重”的氮肥管理策略。更多还原

【Abstract】 This study was conducted to determine the effect of different N application and irrigation rates on N₂O emissions, ammonia volatilization, nitrogen accumulation and utilization efficiency in 0¹00 cm deep layer, tomato yield and fruit quality from a loamy fluvo-aquic soil in North China Plain from 2008 to 2009.Tomato were planted under two different irrigation levels W1 and W1（traditional and water-saving）. Three nitrogen levels were set under W1 and W₂ (N₀:0 kg/ha, N₆₇₅: 675 kg/ha, N900:900 kg/ha) respectively. In this experiment, the main results were as follows:1. The results indicated that reduction of nitrogen regardless of low or high irrigation rate can reduce N₂O fluxes, however, only if low N fertilization was applied, low irrigation result lower N₂O fluxes. In this study condition, Total N₂O emission from the different treatments arrangement as follows: W₁N₉₀₀ （5.304 kg/ha）>W₂N₉₀₀ （4.913 kg/ha）>>W₁N₆₇₅ （3.616 kg/ha）>> W₂N₆₇₅ （2.901 kg/ha）>> W1 N0 （0.563 kg/ha）> W2 N0 （0.511 kg/ha）. The high N₂O emissions from greenhouse tomatoes plots were due to high N₂O losses from the fertilized treatments during the summer and early autumn （Aug, Sept and Oct） and high soil nitrate contents after the N application. The emissions of N₂O per unit N fertilizer applied （low and the conventional rates of N fertilization）were 0.35% 0.53%.2. Decreased N application can significantly reduced the amount of ammonia volatilization in the protection soil of tomato. Total ammonia volatilization from the different treatments arrangement as follows: W₂N₉₀₀ （21.362 kg/ kg/ha）> W₁N₉₀₀ （20.878 kg/ha） >> W₂N₆₇₅ （17.632 kg/ha） > W₁N₆₇₅ （17.466 kg/ha） >> W₁N₀ (6.591 kg/ha > W₂ N₀ （6.390 kg/ha）. Reduced nitrogen fertilizer application is an effective way to reduced ammonia volatilization in greenhouse soil. There is no significant between low and conventional irrigation if the N application rates are same. The reason that the peak of ammonia volatilization is found at 1-3 d after fertilization is the rapid increase of pH after fertilization. In addition ammonia volatilization is higher during high temperature period （August to October）.The volatilization of ammonia per unit N fertilizer applied （low and the conventional rates of N fertilization） were 1.59%¹.68%.3. The results showed that protected vegetable soils from high nitrogen treatments accumulated large pools of nitrates in each layer from 0 to 100 cm soil layer, especially from 0 to 40 cm, meanwhile, leaching out of 40 cm soil layer was large when high irrigation was applied. Nitrate residual in vegetable soils may be cause serious threats to underground water in vegetable growing areas.4. Irrigation and N application had important influence on tomato yield and dry matter accumulatio. In this study condition, no N-application have maintained yield however low quality. No significant increase of yield in high N application （900 kg/ha）treatments,but also increased the content of nitrate in fruit.In summary, the experiment showed that it had the potential of saving water and fertilizer under the premise of maintaining the yield and quality in greenhouse in Xinji city, Hebei province. Reduced N application not reduced the yield significantly, but improved fruit quality, reduce the gas losses of N₂O and ammonia, reduced the accumulation and leaching amount of nitrogen of root zone soil. In this experiment, the best treatment is W₂N₆₇₅ which reduce the N₂O fluxes and ammonia volatilization by 45.3% and 15.5% compare with W1N900 treatment, in addition, W₂N₆₇₅ has highest utilization rate and lowest lossing rate of nitrogen.更多还原