【作者】 毕磊；

【导师】 胡承孝； 谭启玲；

【作者基本信息】 华中农业大学 ， 植物营养， 2010， 硕士

【摘要】 丹江口水库是南水北调中线工程的水源地,重点解决北京、天津、石家庄等沿线20多座大城市的缺水问题,并兼顾沿线生态环境和农业用水,输水水质安全保障极其重要。柑橘种植业作为丹江口的特色产业,目前在库区两岸形成了两条百里柑橘带,并以每年2万亩的速度递增。鉴于控制丹江口库区柑橘产业快速发展可能引起的农业面源污染,本研究在采样调查柑橘园土壤肥力和柑橘营养状况的基础上,选择丹江口库区典型柑橘园,采用径流小区试验和土壤分层取样法研究了推荐施肥、推荐施肥结合分期施肥、推荐施肥结合全园植草等养分管理措施对丹江口库区橘园地表径流输出量、氮磷养分流失量与流失形态、土壤氮磷分布及迁移、柑橘叶片氮磷周年变化、柑橘产量及品质、的影响,主要得出以下结论：1)丹江口库区橘园调查结果显示,由于当地土壤贫瘠再加上长期施肥水平偏低,以及施肥比例不合理(偏施氮、少施磷),库区橘园土壤速效氮、磷含量普遍偏低,再加上各个果园管理水平参差不齐,导致土壤养分变异系数较大。橘树叶片分析结果表明,库区半数以上橘树表现为氮素缺乏。同时,根据上述调查提出了橘园的养分管理措施。2)推荐施肥处理以及各个增量施肥处理均能降低橘园坡地地表径流的输出,其中以推荐施肥处理效果最为显著,与习惯施肥处理比较降低了40.09%的径流输出；可溶性总氮和颗粒态磷为库区橘园径流中氮、磷的主要流失形态,需重点加以控制,化肥的施用并不是造成库区橘园氮磷流失的主要影响因素。提高施肥次数,能明显的降低总氮、可溶性总氮和可溶性总磷的流失,而全园植草则在减少总磷、颗粒态磷和颗粒态氮的流失方面效果显著,分期施肥处理(125%M0+FT)减少了35.96%总氮的流失,植草处理(125%M0+PG)减少了59.31%总磷的流失。但值得注意的是,坡面植草有提高径流中可溶性有机态氮的流失趋势。3)氮肥施用能够显著提高0-80 cm土层碱解氮含量,以20-40 cm土层增幅最大,伴随土层的加深,碱解氮累积峰出峰越晚。磷肥施用主要影响0-40cm土层速效磷含量,其中又以0-20 cm土层变幅最大,只有极少一部分磷移动到40-80 cm土层,因此出现大量磷素垂直迁移的可能性很低。施肥量越高,碱解氮及速效磷0 cm-80 cm土层的储量越大,与增量施肥处理(125% MO)相比,坡面植草可以减少碱解氮及速效磷的储量,然而分期施肥一方面减少碱解氮的储量另一方面又能够提高速效磷的储量。习惯施肥(CF)处理产生的残留硝态氮历经4个月迁移出橘树根层,分期施肥(125%M0+FT)导致硝态氮累积峰率先出现,而坡面植草处理全年并没有出现明显的累积峰；增加施肥次数和坡面植草虽然可以在一定程度上减少60-80 cm土层硝态氮的残留,但影响程度远不及减少施氮量明显,在产量不受较大影响的情况下适当减少施氮量可以大幅降低硝态氮的淋失风险。4)增加施肥次数可以提高叶片氮磷含量,土壤速效氮磷含量的高低决定叶片及果实氮磷的含量。坡面植草处理在试验前期降低叶片氮磷的含量,但通过定期刈草并作为绿肥翻入土壤,在试验后期叶片氮磷含量都有所上升。推荐施肥及各增量施肥处理与习惯施肥处理相比都能不同程度的提高柑橘产量,其中增量施肥处理(125%M0)和植草处理(125%M0+PG)与习惯施肥处理(CF)相比增产效果显著,分别增产43.44%和33.81%,每公顷增收6814元和4339元。推荐施肥结合坡面植草可以促进柑橘果实Vc和可溶性固形物的含量,提高固酸比及可食率,降低总酸含量和单果重,提高了果实营养价值,使果实酸甜适度风味可口。因此,在推荐施肥基础上实行分期施肥,并结合坡面种植三叶草(M0+FT+PG),即可以提高柑橘产量和品质,提高农民收入,又能够有效减少氮磷随地表径流的流失以及硝态氮的淋失,适宜在丹江口库区推广应用。更多还原

【Abstract】 Danjiangkou Reservoir is the water resource of South-North Water Transfer Project, with the aim of satisfying the drink water supply for more than 20 cities, such as Beijing, Tianjin, Shijiazhuang and so on, so the security of water quality in this reservoir is extremely important. Hundred miles of citrus growing belt has formed arround the Danjiangkou Reservoir, and it is increasing annually 13 hm2 nowdays.It is necessary to control the non-point pollution from citrus garden while citrus planting area is raising, based on the investigation of citrus garden soil fertility and tree nutrition, the typical citrus orchards of Danjiangkou Reservoir area was selected, runoff plots experiment and soil stratified sampling method were conducted to study the effects of recommended fertilization, recommended fertilization with split-applied fertilization and recommended fertilization with planting grass on the output of runoff, nitrogen and phosphorus, form of nitrogen and phosphorus,the distribution and migration of soil nitrogen and phosphorus, the annual variation in nitrogen and phosphorus concentrations of citrus leaves, citrus yield and quality. The main conclusions are showed as follows:1)The survey of Danjiangkou Reservoir area citrus orchards showed that:the contents of soil available nitrogen and phosphorus were very low, and long-term of low level fertilization and unreasonable fertilization (partial nitrogen, less phosphorus), coupled with varying management levels of different orchards, was resulted in a larger coefficient of variation of soil nutrients, and more than half of orange trees with deficiency of nitrogen. Meanwhile, we proposed a nutrition management measures for this citrus orchard according to the survey.2) Recommendation fertilization and nutrition management significantly reduced runoff losses,with a 40.09%, compared with the conventional fertilization. Dissolved nitrogen and particle phosphorus were the main loss forms of nitrogen and phosphorus in Danjiangkou reservoir orchard, which should be controlled carefully. Fertilizer application is not the main reason for the loss of nitrogen and phosphorus in Danjiangkou Reservoir area. The loss of total nitrogen, dissolved total nitrogen and dissolved total phosphorus were deceased significantly by increasing the frequency of fertilizer application, and planting grass reduced the loss of total phosphorus, particle phosphorus and particle nitrogen effectively. The loss of 35.96% total nitrogen was decreased by increasing the frequency of fertilizer application while the loss of 59.31% total phosphorus were reduced significantly by planting grass.It is noteworthy that the loss of dissolved organic nitrogen would be increased by planting grass.3)The content of available nitrogen in 0-80 cm soil was increased by applying nitrogen fertilizer significantly, while the concentration of 20-40 cm soil was increased more than the others.The deeper in the soil, the latter the soil available nitrogen accumulation peak appeared. The content of available phosphorus in 0-40 cm soil was raised by applying phosphate fertilizer remarkably, while the concentration of 0-20 cm soil was increased more than the others.There was only a very few amount of available phosphorus move to 40-80 cm soil, that meant it was hardly for soil available phosphorus move vertically. The larger amount of nitrogen and phosphorus was accumulated in 0-80 cm soil when higher rate fertilizer(125% M0) was used, but the accumulations of nitrogen and phosphorus were declined by planting grass, while nitrogen was decreased and phosphorus was increased by more split fertilizer application. The soil nitrate of conventional fertilization treatment (CF) was moved out of root layer after 4 months. Split fertilizer application(125% M0+FT) resulted in accumulation peak of nitrate nitrogen in soil profile firstly, but planting grass treatment(125% M0+PG) had no effect on accumulation of nitrate nitrogen obviously. It was concluded that the nitrate nitrogen of 60-80 cm soil layer could be declined by more split fertilzier application and planting grass, but the most effective measurement in decreasing the risk of nitrate leaching from the soil is to reduce the application rate of nitrogen fertilizer.4) The concentrations of nitrogen and phosphorus of citrus leaves were increased by split fertilizer application more times, the content of soil available nitrogen and phosphorus determine the content of nitrogen and phosphorus in leaves and fruit of citrus. The contents of nitrogen and phosphorus of citrus leaves were declined by planting grass while high application rate fertilizer was used, but raised at the end of experiment after the grass was mowed and buried into the soil. Compared with conventional fertilization treatment, citrus fruits yield was increased by various treatments of recommended fertilization in varying degrees, the citrus yield of incremental fertilization treatment (125% M0) and planting grass treatment(125% M0+PG) increased significantly by 43.44% and 33.81% respectively, with the income increase of 6814 Yuan and 4339 Yuan Renminbi. The concentrations of fruit vitamin C,soluble solids,the ratio of solid to acid and the rate of edible were increased, but the content of total fruit acid and weight per fruit were decreased by planting grass.In a word, planting grass improved the quality of fruit, induced the flavor of fruit to taste sweet and delicious.As a consequence, combined recommendation fertilization with split fertilization and planting grass (MO+FT+PG) not only resulted in higher yield, better quality of citrus and more income, but also in lower loss of nitrogen, phosphorus and the leaching of nitrate. The nutrient management measures mentioned above possess of popularization and application value for the citrus orchard in Danjiangkou Reservoir areas.更多还原