【作者】 吴建新；

【导师】 王殿武； 邹国元； 王甲辰；

【作者基本信息】 河北农业大学 ， 土壤学， 2010， 硕士

【摘要】 保护地作物具有产量高、需肥量大等特点。在实际生产中,过量施肥现象比较严重,造成氮肥利用率较低,大量速效氮累积在土壤中,易引起淋失,造成地下水体硝酸盐污染。针对我国蔬菜生产中不合理施肥导致的氮素损失及环境污染问题,以彩色甜椒和罗马花椰菜为供试作物,研究了京郊保护地条件下单施有机肥、常规施肥及优化施肥措施对蔬菜产量、氮肥利用率、土壤剖面硝态氮分布特征以及土壤—蔬菜系统氮素平衡的影响。主要结果如下:(1)施肥能够增加彩色甜椒与罗马花椰菜的经济产量。同对照相比,常规施肥与优化施肥处理彩色甜椒增产率分别为20.17%和14.97%,罗马花椰菜增产率分别为32.81%和48.99%,均达到显著水平,单施有机肥未能显著增加罗马花椰菜经济产量;相比常规施肥,优化施肥处理彩色甜椒产量虽有所降低,但未达显著水平。另外,优化施肥较常规施肥在一定程度上减少了两季蔬菜可食部分NO3--N含量;所有处理两季蔬菜可食部分NO3--N含量均远低于蔬菜可食部分硝酸盐的食用卫生一级标准。(2)研究了施肥对蔬菜氮素利用的影响,结果表明:在彩色甜椒生长季,优化施肥与常规施肥的表观氮肥利用率分别为9.11%和10.42%,无机氮肥利用率分别为5.59%和3.02%,相差均不大;罗马花椰菜生长季,优化施肥的表观氮肥利用率及无机氮肥利用率分别为40.21%和36.39%,比常规施肥分别提高了20.04%和19.37%.(3)通过彩色甜椒—休闲—罗马花椰菜轮作试验,揭示了不同措施下0~200 cm土体硝态氮分布特征。随着时间的推移,相比定位试验初始土壤剖面硝态氮含量,对照、单施有机肥、优化施肥处理均表现出明显的降低趋势,而常规施肥于彩色甜椒收获后、休闲期结束和罗马花椰菜收获后分别在40~60 cm、80~100 cm、120~140 cm土层出现土壤硝态氮含量累积峰,峰值分别为77.98 mg/kg,74.44 mg/kg和65.51 mg/kg,且均高于初始土壤相对应土层硝态氮含量。两季蔬菜轮作后,对照及单施有机肥处理0~160 cm剖面硝态氮含量较低,160~200 cm范围内逐渐升高,但均未超过20 mg/kg,整体剖面未见明显的累积峰。其中,罗马花椰菜生长季优化施肥及常规施肥处理在120~140 cm范围内出现累积峰,峰值分别为65.51 mg/kg和28.03 mg/kg。两季蔬菜收获后0~200 cm剖面硝态氮累积量优化施肥较常规施肥分别减少了631.05 kg/hm2和613.68 kg/hm2,均达到显著水平。(4)土壤—蔬菜系统下氮素表观平衡结果表明:同常规施肥相比,优化施肥处理下彩色甜椒和罗马花椰菜单季的氮素表观损失量分别减少9.54 kg/hm2和169.69 kg/hm2。彩色甜椒—休闲—罗马花椰菜轮作下各处理氮素表观损失量在28.26 kg/hm2~1261.14 kg/hm2之间,对照及单施有机肥处理均较低,优化施肥处理显著低于常规施肥处理,各处理表观损失量大小为常规施肥>优化施肥>单施有机肥>对照。更多还原

【Abstract】 Crops in protected field possess the advantage of high yield, high fertilizer demand and so on. The phenomenon of excessive fertilization which lead to low N use efficiency is serious, and results in high accumulation of available N in actual production process which may cause N leaching easily, also lead to nitrate contamination of groundwater. Nitrogen losses and the pollution of environment due to irrational fertilization in vegetable production system has been becoming more and more concerned to the whole world. Aiming at this problem, a series of field experiments with Sweet Bell Pepper and Broccoli Romanesco were carried out in protected field in Beijing suburb. Four treatments were designed to study on the effects of crop yield, quality, N use efficiency, soil NO3--N distribution and apparent N balance of soil-crop system. These treatments were no fertilizer, manure only, conventional fertilization and optimized fertilization. The results showed as follows:(1) Fertilization increased economic yields of Sweet Bell Pepper and Broccoli Romanesco. Contrasted with no fertilizer, the yields of optimized fertilization and conventional fertilization enhanced significantly by 20.17% and 14.97% in Sweep Bell Pepper growing season, while 32.81% and 48.99% in Broccoli Romanesco growing season. Manure didn’t enhance economic yield of Broccoli Romanesco significantly. Contrasted with conventional fertilization, optimized fertilization didn’t reduce the yield of Sweet Bell Pepper significantly. In addition, optimized fertilization decreased fruits NO3--N content in both two vegetables to a certain degree. The edible parts NO3--N content in all treatments were much lower than the standard of primary food sanitation standard.(2) The results of effects of fertilization on the nitrogen utilization showed that: Nitrogen apparent use efficiency of optimized fertilization and conventional fertilization were 9.11% and 10.42% respectively and inorganic nitrogen fertilizer use efficiency were 5.59% and 3.02% in Sweep Bell Pepper growing season. Nitrogen apparent use efficiency and inorganic nitrogen fertilizer use efficiency of optimized fertilization were 40.21% and 36.39% which enhanced 20.04% and 19.37% contrasted with conventional fertilization respectively in Broccoli Romanesco growing season.(3) The nitrate distribution characteristics in the depth of 0~200 cm soil profiles were studied on Sweet Bell Pepper-Fallow-Broccoli Romanesco rotation system. Compared with the initial experiment, the soil NO3--N content of no fertilization, manure and optimized fertilization fell obviously, while the soil profiles NO3--N content in the depth of 40~60 cm, 80~100 cm, 120~140 cm of conventional fertilization accumulated the highest NO3--N content at the end of every growing season, the peak value were 77.98 mg/kg, 74.44 mg/kg and 65.51 mg/kg, respectively. At the end of the experiment, relative in initial experiment, soil NO3--N accumulation in conventional fertilization and organic manure treatment were lower at 0~160 cm soil profiles and higher in 160~200 cm soil profiles, the soil NO3--N content of conventional fertilization and manure did not higher than 20 mg/kg and without the peak of accumulated nitrate either. While accumulated nitrate peak in 120~140 cm soil profile was found in optimized fertilization and conventional fertilization in Broccoli Romanesco growing season, the peak value were 65.51 mg/kg and 28.03 mg/kg respectively. Compared with conventional fertilization, after the two crops’harvest, the NO3--N residue of optimized fertilization in the depth of 0~200 cm decreased 631.05kg/hm2 and 613.68 kg/hm2, respectively and both showed significant difference.(4) The results of the apparent nitrogen balance in soil vegetable system indicated: Compared with conventional fertilization, the apparent nitrogen balance of optimized fertilization in Sweet Bell Pepper and Broccoli Romanesco growing season were decreased 9.54 kg/hm2 and 169.69 kg/hm2, respectively. The apparent nitrogen losses of the four treatments varied from 28.26 kg/hm2 to 1261.14 kg/hm2 in the Sweet Bell Pepper-Fallow-Broccoli Romanesco rotation system. The apparent nitrogen balance of no fertilizer and manure were very low, while optimized significantly lower than that of conventional. The apparent nitrogen losses were in an order as follows: conventional fertilization> optimized fertilization>manure>no fertilizer.更多还原