【作者】 章君果；

【导师】 达良俊；

【作者基本信息】 华东师范大学 ， 生态学， 2010， 硕士

【摘要】 在蔬菜生产过程中大量的氮磷投入,导致土壤氮磷大量盈余,其结果导致土壤氮磷不断流失,造成水体养分过剩而形成水体富营养化污染。过量使用氮肥,不仅造成水体污染,而且蔬菜的产量和品质也受到一定影响,对蔬菜生产带来很大压力。基于这些问题,对蔬菜生产中养分差异化管理的研究有着极为重要的意义。本文选取了滇池流域蔬菜设施保护地油麦菜种植区进行研究。油麦菜是滇池流域开始大面积种植的一种新蔬菜作物,而对油麦菜养分迁移状况的研究未见到报道。在2008年8月到9月进行油麦菜田间试验,分为高量施肥和低量施肥两个组别进行,每个组9个施肥处理水平,并在试验过程中对植株样和土样进行采集,对油麦菜产量、油麦菜硝酸盐含量,植株样总氮、总磷,土壤总氮、总磷、有效磷、碱解氮和有机质进行测定,结合养分差异来讨论油麦菜对土壤氮磷的吸收,油麦菜产量、硝酸盐含量和土壤氮磷迁移变化特征及环境社会效应。其主要结果表明：1.氮磷投入量比高量施肥减少46.4%,油麦菜增产32.4%。适宜的氮磷投入量和施用比例是油麦菜高产的重要因素,产量较高时氮的施用范围为180-225kg·ha-1,磷肥可以少量施用,施磷量控制在63 kg·ha-1左右,可以达到经济效益和环境效益的协调。在适宜的氮施用量范围内,油麦菜对氮的平均吸收率达到25%,最高达到了28%,成熟期氮吸收量比生长期高。油麦菜对磷的吸收率很低,在适量施磷范围内,对磷的吸收率也只有10%左右。2.油麦菜硝酸盐含量随氮素水平的提高呈递增趋势,磷素具有能够抑制硝酸盐的积累的作用。油麦菜产量达到较高水平,而油麦菜食用部分硝酸盐含量符合中国叶菜类硝酸盐含量标准。控制氮磷的合理配施只是有效降低硝酸盐含量的一个重要方面,并不是一个根本因素,只能在一定程度上对蔬菜硝酸盐含量有影响。3.短期内土壤总氮在各施肥处理之间并没有规律性变化；0-20cm碱解氮和施氮量表现出了正相关；总磷在0-40cm土层随施磷量的增加而增加,表现出显著线性正相关(P<0.05)；有效磷和总磷的变化趋势一致,0-40cm有效磷和施磷量显著线性正相关(P<0.05)；有机质在短期内变化不大。在垂直梯度上,土壤养分随深度增加而递减。4.土壤总氮积累量和施氮量呈现了显著线性正相关(P<0.05),这是农业施肥处理中一个普遍现象,与种植何种作物关系不大。磷在土壤中积累效益比较显著,积累量达到80%以上。在0-20cm和20-40cm土层总磷和施磷量都表现出了显著线性正相关(P<0.05)。适量施氮量土壤氮积累量表现出了减少,而过量施氮则表现出了盈余；施磷处理都表现出了磷积累量的盈余。5.适量施肥和过量施肥相比氮磷化肥投入减少58.5%,油麦菜产量增加24.2%,单季每公顷油麦菜,农户可节约化肥投入1814.2元,增加收入13275元。滇池流域油麦菜种植区,适量施肥每年将减少氮损失101.53t,减少磷损失60.86t,每公顷油麦菜在适量施肥时将获得直接环境经济效益401.14元,滇池流域油麦菜种植区每年将获得直接环境经济效益84.2万元。综合以上研究结果,土壤氮磷的损失量和积累量与氮磷施用量直接相关,与种植蔬菜作物关系不大。从结合农户的经济效益和环境效益的综合考虑,建议实施“控氮少磷”的养分差异化管理,油麦菜种植过程中氮素控制在现有施肥量的1/2以内,其适宜施用量为180-225 kg·ha-1,油麦菜对磷素的吸收比较少,可以采用“少磷”措施,将磷肥的施用量减少在63 kg·ha-1左右。更多还原

【Abstract】 In the vegetable production, as the use of chemical fertilizer is increasing constantly, a large number of farmland nutrients aggravates a huge surplus of soil nitrogen and phosphorus, which inflow water bodies and resulted in environmental pollutions. The loss use of nitrogen fertilizers will not only cause water pollutions, but also impact the yield and quality of vegetables, which brought a lot of pressure on vegetable production. Because of these problems, differences of Nutrient Management research has significant importance in vegetable production.This paper selected lettuce vegetable areas of facilities vegetable soil in Dianchi Lake basin. Lettuce bengined planting widely and was not studied on Metastaic Characteristics of N、P. From August to september in 2008, through lettuce field experiment of high fertilization level and low fertilization level, the Indicators of lettuce yield and nitrate content, lettuce TN and TP, soil TN and TP, soil available phosphorus, soil available nitrogen and organic matter had been analyzed. The experiment set 9 fertilizer treatments. The behavior characteristics of lettuce absorption, lettuce yield, nitrate content, soil nitrogen and phosphorus transfer and ecological benefit law had been probed into combining with discussion of Differences of Nutrient. The results of our study are as follows:1. The yield of Lettuce was increased by 32.4%, when the rates of N and P were reduced to 46.4% of high fertilizer. N、P, applied in proper combinations, is an important factor for high yield of lettuce. The optimal nitrogen level for high Lettuce yield was 180-270 kg·ha-1, and the optimal phosphorus level was small and about 63 kg·ha-1, in order to coordination economic benefits and environmental benefits. On appropriate nitrogen application, the absorption rate of lettuce reached over 20%, while the highest value 28%. In maturing stage, the nitrogen absorption amount of lettuce was higher than that in growing stage. The phosphorus absorption rate of lettuce was low. On appropriate phosphorus application, the phosphorus absorption rate was only about 10%. 2. The content of nitrate increased with the increasing of nitrogen levels. Appropriate phosphorus levels could restrain nitrate accumulation in Lettuce. Proper N、P combinations could improve the quality of lettuce and increase yield. The nitrate content of edible parts of lettuce accorded with the standard of nitrate pollution in China. The control of nitrogen and phosphorus fertilizer is a important aspect of decreasing nitrate content. It is important that nitrate content was reduced by reasonable control of nitrogen and phosphorus fertilizers.3. Soil total nitrogen had no law in treatment level. The correlation analysis showed that the available nitrogen within 0-20cm soil layer was significantly positively related with the nitrogen application(P<0.05). In 0-40cm soil layer, the total phosphorus increased with phosphorus application amount. The trend of available phosphorus was consistent with the total phosphorus. The total phosphorus and available phosphorus in 0-40cm soil layer showed significant positive linear correlation with phosphorus application amount(P<0.05). Organic matter had little change in a short period. In the vertical gradients, the soil nutrients decreased with depth decrements.4. The correlation analysis showed that the total nitrogen accumulation was significantly positively linear related with the nitrogen application(P<0.05). This was an common phenomenon and had little relationship with crop. In the soil phosphorus accumulation was more significant than nitrogen and reached over 80%. In 0-20cm and 20-40cm soil layer, total phosphorus showed significant positive linear correlation with phosphorus application amount(P<0.05). The soil nitrogen accumulation decreased in appropriate nitrogen application and increased in excess nitrogen application. P-fertilizer showed a surplus of phosphorus accumulation.5. In appropriate nitrogen application, the yield of lettuce was increased by 32.4%,when the rates of N and P were reduced to 46.4% of high fertilizer. Farmers could save fertilizer of 1814.2yuan per hectare and the income increased by 13275yuan per hectare by applying appropriate fertilizers. In lettuce-growing areas of Dianchi Lake Basin, the appropriate nitrogen application would reduce nitrogen loss of 101.53t and phosphorus loss 60.86t. There would be direct environmental economic benefit 401.14yuan per hectare lettuce in appropriate nitrogen application and in lettuce-growing areas of Dianchi Lake Basin there was direct environmental economic benefit 842,000yuan per year.Based on the above result, the loss and accumulation of soil nitrogen and phosphorus was related to the amount of nitrogen and phosphorus. Involving farmers’ economic benefits and environmental benefits, this paper proposed implementing differences of nutrient management about "control of nitrogen and little phosphorus".the optimal nitrogen level was 1/2 of current level and was 180-225 kg·ha-1. Phosphorus absorption of lettuce was little and farmers could apply a little and the application of phosphorus was about 63 kg·ha-1.更多还原