本文選題：濟(jì)陽葛店灌區(qū) + 氮素�。� 參考：《濟(jì)南大學(xué)》2016年碩士論文

【摘要】：氮素是作物生長及發(fā)育的重要營養(yǎng)元素之一,自然條件下,氮素一般處于動態(tài)平衡,而農(nóng)田生態(tài)系統(tǒng),人們?yōu)樽非笞魑锂a(chǎn)量的最大化,長期向土壤中不合理過量的投入氮肥,導(dǎo)致水土環(huán)境中氮素含量積累,加之農(nóng)田生態(tài)系統(tǒng)不同于自然生態(tài)系統(tǒng),其人為干擾程度較大,且沒有足夠的自凈能力,不合理的人類活動會對其產(chǎn)生較大影響,進(jìn)而影響農(nóng)田氮素遷移淋失特征,據(jù)前期調(diào)查濟(jì)南葛店引黃灌區(qū)水土環(huán)境中氮素面源污染嚴(yán)重,本文旨在研究水稻-小麥生長期內(nèi)土壤剖面、淺層地下水環(huán)境中氮素累積分布、淋失特征及影響因素分析,基于Hydus-3D軟件模擬不同設(shè)計施肥灌溉方案下包氣帶氮素遷移轉(zhuǎn)化特征,確定適合灌區(qū)較優(yōu)的水肥方案。主要研究內(nèi)容及結(jié)論如下:(1)水稻-小麥作物生長年內(nèi)系統(tǒng)采集0~120cm土壤剖面土壤樣品,分析不同作物生長期土壤剖面氮素累積分布特征。研究表明,水稻-小麥生長年內(nèi),硝態(tài)氮與銨態(tài)氮含量變化趨勢基本一致且隨施肥灌溉處理其含量變化趨勢響應(yīng)明顯;此外,水稻生長期內(nèi),土壤剖面氮素在80~100cm土壤累積現(xiàn)象明顯,硝態(tài)氮凈累積量為97.46kg/hm2,銨態(tài)氮凈累積量為3.65 kg/hm2。(2)利用灌區(qū)土壤樣品原狀填充有機玻璃土柱進(jìn)行室內(nèi)實驗,收集0~120cm土壤剖面滲濾液測定氮素含量,研究作物不同時期0~120cm土層剖面氮素淋失特征,結(jié)果表明,隨作物生長發(fā)育,土壤剖面氮素淋失量減少,作物生長初期淋失量最多,成熟期量淋失量最少;相比總氮、銨態(tài)氮,硝態(tài)氮濃度曲線斜率大且穩(wěn)定最小濃度時間短,與硝態(tài)氮最易淋失特點相符,土壤銨態(tài)氮含量少且礦化生成銨態(tài)氮明顯,致使銨態(tài)氮淋失量波動較小。(3)采集土壤樣品的同時采集淺層地下水,觀測淺層地下水埋深變化,分析淺層地下水中氮素含量及其影響因素,淺層地下水中氮素含量隨作物生長發(fā)育明顯升高,水稻部分生長期硝態(tài)氮含量大于30mg/L,低于淺層地下水質(zhì)量Ⅴ類標(biāo)準(zhǔn),水稻-小麥生長年內(nèi)淺層地下水中銨態(tài)氮含量均大于0.5mg/L,最大值為1.83mg/L,作物收割休閑期含量為0.75mg/L,低于淺層地下水質(zhì)量Ⅳ類標(biāo)準(zhǔn),說明灌區(qū)不合理的施肥灌溉已經(jīng)污染淺層地下水水環(huán)境。(4)對影響土層氮素累積因素土壤有機質(zhì)、土壤質(zhì)地、灌水量分析,得出有機質(zhì)與土壤剖面氮素具有較好的正線性相關(guān),有機質(zhì)是土壤氮素賦存的重要載體,不同土壤質(zhì)地氮素累積量存在較大差異,累積量大小順序:粘壤土壤土砂質(zhì)壤土,灌溉對水土環(huán)境中氮素的分布、淋失特征影響較大,過量灌溉易造成氮素淋。(5)為緩解灌區(qū)氮素對土壤、淺層地下水質(zhì)量的影響,設(shè)計不同水肥方案,基于Hydus-3D軟件模擬包氣帶氮素遷移轉(zhuǎn)化,優(yōu)化提出較適合灌區(qū)的水肥方案。
[Abstract]:Nitrogen is one of the important nutrient elements in crop growth and development. Under natural conditions, nitrogen is generally in dynamic balance. In order to maximize crop yield, the farmland ecosystem, people in order to achieve the maximum crop yield, long-term unreasonable excessive input of nitrogen fertilizer in the soil. As a result of nitrogen accumulation in soil and water environment and the difference between farmland ecosystem and natural ecosystem, the degree of human disturbance is greater, and there is not enough self-purification ability. Unreasonable human activities will have a great impact on it. According to the investigation of nitrogen non-point source pollution in the soil and water environment of Gedian Yellow River Irrigation area in Jinan, the purpose of this paper is to study the soil profile in rice and wheat growing period and the accumulation and distribution of nitrogen in shallow groundwater environment. Based on Hydus-3D software, the characteristics of nitrogen transfer and transformation in aeration zone were simulated under different fertilization and irrigation schemes, and the suitable water and fertilizer schemes were determined. The main contents and conclusions are as follows: (1) soil samples of 0~120cm soil profile were collected systematically during the growing years of rice and wheat crops, and the characteristics of soil nitrogen accumulation and distribution in different crop growing periods were analyzed. The results showed that the change trend of nitrate nitrogen and ammonium nitrogen content was basically the same during the growing years of rice and wheat, and the change trend of nitrate and ammonium nitrogen content was obvious with fertilization and irrigation, in addition, during the rice growing period, the change trend of nitrate nitrogen and ammonium nitrogen content in rice growing period was obvious. The accumulation of nitrogen in soil profile was obvious in 80~100cm. The net accumulation of nitrate and ammonium were 97.46 kg / hm ~ 2 and 3.65 kg 路hm ~ (2) 路hm ~ (2) respectively. (2) the soil samples were filled with organic glass soil column in irrigation area. 0~120cm soil profile leachate was collected to determine nitrogen content, and the characteristics of nitrogen leaching in 0~120cm soil profile at different crop stages were studied. The results showed that the nitrogen leaching loss in soil profile decreased with crop growth and increased in early crop growth. Compared with total nitrogen and ammonium nitrogen, the curve slope of nitrate concentration curve was larger and the time of stable minimum concentration was shorter than that of total nitrogen, which was consistent with the characteristics of most easy leaching of nitrate nitrogen, and the soil ammonium nitrogen content was less and mineralized to produce ammonium nitrogen obviously. As a result, the amount of ammonium nitrogen leaching fluctuates less. (3) collecting soil samples and collecting shallow groundwater, observing the change of shallow groundwater depth, analyzing nitrogen content in shallow groundwater and its influencing factors. Nitrogen content in shallow groundwater increased obviously with crop growth and development. Nitrate nitrogen content in some growing stages of rice was more than 30 mg / L, which was lower than the class V standard of shallow groundwater quality. During the growing years of rice and wheat, the content of ammonium nitrogen in shallow groundwater was greater than 0.5 mg / L, the maximum value was 1.83 mg / L, and the content in crop harvest and leisure period was 0.75 mg / L, which was lower than the grade 鈪，

本文編號：2056630