【作者】 李银坤；

【导师】 武雪萍；

【作者基本信息】 中国农业科学院 ， 土壤学， 2010， 硕士

【摘要】 随着人们对蔬菜需求量的增加,菜农为获得高产,盲目提高施肥与灌水量,而忽视科学水肥管理的理念。如今,蔬菜生产中不合理的水肥管理导致的土壤环境恶化、肥料利用率低以及蔬菜质量品质下降等问题已经十分严重。明确保护地土壤的氮素损失途径,探讨蔬菜生产中科学的水肥管理措施是我国设施农业可持续发展的需要。迄今为止,有关保护地中不同水氮条件下系统分析土壤的氨挥发、反硝化和N2O排放以及土壤溶液中无机氮淋失的研究较为少见。本研究在河北省辛集市马庄科园农场开展了田间试验和15N示踪的微区试验,田间试验和15N示踪的微区试验均设置6个处理,将减量灌水、减量施氮与习惯水氮处理进行对比研究:(1)习惯灌水、不施氮处理(灌水量为7470 m3·hm-2);(2)习惯灌水、减施氮25%处理(灌水与氮肥用量分别为7470 m3·hm-2和900 kg·hm-2)(;3)习惯水氮处理(灌水与氮肥用量分别为7470 m3·hm-2和1200 kg·hm-2);(4)减量灌水30%、减施氮50%处理(灌水与氮肥用量分别为5190 m3·hm-2和600 kg·hm-2)。(5)减量灌水30%、减施氮25%处理(灌水与氮肥用量分别为5190 m3·hm-2和900 kg·hm-2);(6)减量灌水30%、习惯施氮处理(灌水与氮肥用量分别为5190 m3·hm-2和1200 kg·hm-2)。研究了不同灌水与施肥条件对黄瓜季保护地的氨挥发,硝化、反硝化速率,N2O损失,硝态氮淋失,氮肥15N的动态与去向以及产量品质的影响。以期为探讨保护地蔬菜生产中氮素损失途径和建立合理的水氮优化管理技术提供科学的依据。在本试验条件下,取得以下研究结论:1、黄瓜生长季农田氨挥发损失总量为11.4~26.6 kg·hm-2、氨挥发量占氮肥用量的0.89%~1.27%氮肥对氨挥发的贡献率为31.8%~57.1%。在减量灌水条件下,减量施氮25%与50%处理(W2N900与W2N600)的氨挥发损失量比习惯施氮处理(W2N1200)分别降低了22.1%和37.2%;而相同氮用量下,减量灌水与习惯灌水相比,氨挥发损失量增加了3.0%~4.8%。2、黄瓜生长季农田总硝化速率与反硝化速率最高分别达523μgN·kg-2·h-1、351μgN·kg-2·h-1。其中在减量灌水条件下,减施氮25%和50%处理(W2N900和W2N600)与习惯施氮处理(W2N1200)相比,总硝化速率分别降低了19.9%、26.7%;反硝化速率分别降低了9.8%、20.8%。相同施氮量下,减量灌水与习惯灌水相比,总硝化速率与反硝化速率的降低幅度分别为2.5%~11.5%,19.5%~26.0%。3、黄瓜生长季农田N2O损失量为0.74~7.92 kg·hm-2,占氮肥用量的0.25%~0.60%,而氮肥对N2O损失的贡献率为67.8%~90.6%。在减量灌水条件下,减量施氮25%与50%处理(W2N900与W2N600)的N2O损失量比习惯施氮处理(W2N1200)分别降低了39.9%和54.1%;而相同氮用量下,减量灌水与习惯灌水处理相比,N2O损失量可降低36.8%~45.2%。4、黄瓜生长季农田无机氮的淋失量为120~595 kg·hm-2,占施氮量的25.6%~39.6%。硝态氮是土壤无机氮淋失的主要形式,可占到无机氮淋失总量的99.7%以上。在减量灌水条件下,减施氮25%和50%处理(W2N900和W2N600)与习惯施氮处理(W2N1200)相比,100 cm土体硝态氮的淋失量分别降低了30.0%和46.0%;而相同氮用量下,减量灌水与习惯灌水处理相比,硝态氮淋失量降低了14.9%~23.8%。5、在本试验中的减量灌水条件下,减施氮25%和50%处理(W2N900与W2N600)的产量比习惯施氮处理(W2N1200)分别提高了4.5%和5.4%。在减施氮25%的条件下,减量灌水处理(W2N900)比习惯灌水处理(W1N900)提高了3.4%。6、不同水氮处理对黄瓜品质亦有显著的影响。其中在减量灌水条件下,减施氮25%和50%处理(W2N900与W2N600)与习惯施氮处理(W2N1200)相比,果实硝酸盐含量分别降低了9.8%和13.5%,可溶性糖含量则分别增加了13.1%和12.9%。在减施氮25%的条件下,减量灌水处理(W2N900)比习惯灌水处理(W1N900)的果实硝酸盐含量降低了3.9%,而可溶性糖含量则增加了7.3%。7、不同水氮处理对黄瓜叶片的瞬时水分利用效率(WUE)具有显著的影响。其中在减量灌水条件下,减施氮50%处理(W2N600)与习惯施氮处理(W2N1200)相比,可提高1.2%~9.8%。在减施氮25%的条件下,减量灌水处理(W2N900)的叶片瞬时水分利用效率(生育期均值)比习惯灌水处理(W1N900)提高了6.1%。8、15N微区试验结果表明,不同水氮条件下黄瓜全株对氮肥15N的吸收量在177~297 kg·hm-2,果实、叶、茎、根对氮肥15N吸收量依次降低。黄瓜当季的氮肥利用率为23.6%~32.8%,在2种灌水条件下分别以减施氮25%处理(W1N900)和减施氮50%处理(W2N600)的氮肥利用率最高,与相同条件下的习惯施氮处理(W1N1200与W2N1200)相比,其利用率分别提高了4.57、6.96个百分点。综合分析,本试验条件下,处理W2N600和W2N900既具有较高的光合速率和氮肥利用率,又具有最高的水分利用效率,而且产量高,品质好,是较为合理的水氮组合。2年的试验研究表明,通过合理施肥、科学控制灌溉量,在当地习惯水氮管理的基础上,减量灌溉30%、减施氮25%~50%的情况下,不会影响到黄瓜产量,因此,推荐河北省保护地春季黄瓜生产,灌水量为5190 m3·hm-2,施氮量为600~900 kg·hm-2。更多还原

【Abstract】 With the human demand of vegetables increased, farmers ignore the scientific concept of water and fertilizer management. In order to obtain high-yield of vegetable, the amount of fertilizer and irrigation water is improved blindly. Up to now, the problems of soil environment deterioration, low fertilizer use efficiency and worse vegetables quality are very serious. They are all caused by the unreasonable management of water and fertilizer in vegetable production. The way of nitrogen loss and also scientific management of water and fertilizer should be defined in vegetable production. These are urgent for sustaining development of facility agriculture. Up to date, there have few researches on comprehensive and systematic study about the ammonia volatilization, de-nitrification, N2O emissions and the leaching loss of inorganic nitrogen. Field plot experiments and micro-plot experiments of 15N tracing were established in Xinji City, Hebei Province. Our experiment included six treatments both in field trail and micro-plot experiment with 15N tracing to compare the study on reduction of irrigation, nitrogen and conventional of water and nitrogen treatments: (1) conventional water application and with no nitrogen applied (irrigation amount, 7470 m3·hm-2); (2) conventional water application and with nitrogen decreased by 25% applied (irrigation amount, 7470 m3·hm-2; amount of nitrogen, 900 kg·hm-2); (3) conventional water and nitrogen application (irrigation amount, 7470 m3·hm-2; amount of nitrogen, 1200 kg·hm-2); (4) water decreased by 30%, nitrogen decreased by 50% applied (irrigation amount, 5190 m3·hm-2; amount of nitrogen, 600 kg·hm-2); (5) water decreased by 30%, nitrogen decreased by 25% applied (irrigation amount, 5190 m3·hm-2; amount of nitrogen, 900 kg·hm-2); (6) water decreased by 30%, conventional nitrogen application, (irrigation amount, 5190 m3·hm-2; amount of nitrogen, 1200 kg·hm-2). We studied the effects of different amount of water and nitrogen on the field ammonia volatilization, denitrification, N2O emissions, and the leaching loss of nitrate nitrogen and also the fate of 15N and cucumber quality in this research. In our experiment, the main results were as follows:1. During the cucumber growing season, ammonia volatilization content of the field was 11.4~26.6 kg·hm-2 and the loss ratio of nitrogen was 0.89%~1.27% and the contribution rate of nitrogen was 31.8%~57.1%. The ammonia volatilization contents of the treatment with W2N900 and W2N600 decreased by 22.1%, 37.2% respectively under the reduction of irrigation water conditions. Compared with conventional water applied (W2N1200), the ammonia volatilization content of reduction water treatment increased by 3.0%~4.8% with the same nitrogen conditions.2. The gross nitrification rates and denitrification rates of field were 523μg N·kg-2·h-1、351μg N·kg-2·h-1 respectively. The gross nitrification rates of the treatment with W2N900 and W2N600 decreased by 19.9%, 26.7% respectively and the denitrification rates decreased by 9.8% and 20.8% under the reduction of irrigation water conditions. The gross nitrification rates and denitrification rates decreased by 2.5%~11.5%, 19.5%~26.0% respectively in the treatment of reduction water compared to conventional water (W2N1200) under the same nitrogen conditions.3. The N2O loss amount of field was 0.74~7.92 kg·hm-2, and the loss ratio of nitrogen was 0.25%~0.60%, the contribution rate of nitrogen was 67.8%~90.6%. The N2O loss amount of the treatment with W2N900 and W2N600 decreased by 39.9%, 54.1% respectively under the reduction of irrigation water conditions. The treatment with reduction of water compared to conventional water, the N2O loss amount decreased by 36.8%~45.2% under the same nitrogen conditions.4. Inorganic nitrogen leaching amount was 120~595 kg·hm-2, account for 25.6%~39.6% of nitrogen applied. Nitrate nitrogen was the main form of the leaching loss of inorganic nitrogen, and the ratio was 99.7%. The nitrate nitrogen leaching amount of the treatments with W2N900 and W2N600 decreased by 30.3%, 46.0% respectively under the reduction of irrigation water conditions. The treatment with reduction of water compared to conventional water, the nitrate nitrogen leaching amount decreased by 14.9%~23.8% under the same nitrogen conditions.5. Compared with W2N1200, the yield of treatment W2N900 and W2N600 increased by 4.6%, 5.4% respectively under the reduction of irrigation water conditions. Compared with W1N900, the cucumber yield of W2N900 increased by 3.4% under the same of nitrogen applied.6. The effects of different water and nitrogen on quality were significantly. Compared with W2N1200, the NO3- amount of cucumber in the treatment W2N900 and W2N600 decreased by 9.8%, 13.5% respectively, and soluble sugar increased by 13.1%, 12.9% respectively under the reduction of irrigation water conditions. Compared with W1N900, the amount of NO3- in the treatment W2N900 decreased by 3.9%, while soluble sugar increased by 7.3%.7. The effects of different water and nitrogen conditions on WUE were significantly. Compared with W2N1200, the water use efficiency of treatment W2N600 decreased by 1.2%~9.8% with the reduction of irrigation water conditions. Compared with W1N900, the water use efficiency of treatment W2N900 decreased by 6.1% with the same amount of nitrogen applied.8. Micro-plot experiment with 15N tracing showed that absorbed of nitrogenous fertilizer 15N by cucumber was 177~297 kg·hm-2. The amount of absorption by fruit, leaf, stem, and root were reducing in turn. Nitrogen use efficiency was 23.6%~32.8%. The treatments W2N900 and W2N600 had the highest nitrogen use efficiency. Compared with the treatment W1N1200 and W2N1200, they increased by 4.57, 6.96 percentage respectively.In conclusion, the treatments W2N900 and W2N600 were much more reasonable management approach. Because they not only had the higher growth characteristics, water and nitrogen use efficiency, but also with the higher cucumber yield and quality. Two years experiment showed that the water decreased by 30% and nitrogen decreased by 25%~50% would not affect the yield of cucumber. So we recommended that the water irrigate amount was 5190 m3·hm-2, and the amount of nitrogen was 600~900 kg·hm-2 in this area.更多还原