水稻秸秆生物质炭基缓释肥的制备与应用研究

发布时间：2018-10-08 17:42

【摘要】：与传统肥料相比,包膜缓控释肥能有效减轻土壤氮素养分的流失。但目前大部分包膜材料均为高分子聚合物,难降解易累积,长期使用极易破坏土壤结构。因此寻求新的缓释包膜材料,制备环境友好型缓释肥是目前该领域研究的热点。另一方面,我国水稻秸秆资源丰富,但秸秆还田往往促进稻田甲烷等温室气体的排放。生物质炭具有高度稳定性和较强的养分吸附持留特性,具备作为缓释肥包膜材料的基本要求。如果能将水稻秸秆炭化用于制备缓释肥,则无疑将为水稻秸秆资源化利用和环保型缓释肥生产提供一条新技术途径,也将为我国农田生态系统面源污染防治和农业固碳减排作出重大贡献。基于此,本论文通过采用自燃内热式炭化炉,以水稻秸秆为原料,开展了秸秆生物质炭化中试生产试验；借助正交试验,以秸秆生物质炭为主料,优化制备适合水稻生长的炭基缓释肥；并在盆栽和大田试验条件下验证了炭基缓释肥对水稻生产和稻田氮素流失的影响。主要研究结果如下： (1)借助具有自主知识产权的自燃内热式炭化炉,以水稻秸秆为试材,综合考察风机进风量和炭化停留时间对生物质炭炭化得率和碳含量的影响。结果表明进风量为2600m3/h和停留时间为1h的运行条件下制备得到的生物质炭比较适合用作制备炭基缓释肥的研究材料。在该条件下,水稻秸秆经400-500℃炭化后,生物质炭的得率可达34.9%,碳含量高达53.67%。 (2)以秸秆生物质炭和普通复合肥料为基料,通过正交试验,比较分析了生物质炭、膨润土与煤炭腐殖酸含量以及粘结剂类型对炭基缓释肥中氮养分缓释效果的影响。结果发现生物质炭含量为25%,膨润土含量为4%,煤炭腐殖酸含量10%,并以改性玉米淀粉为粘结剂条件下制备的炭基包膜缓释肥缓释效果最佳,达到国家缓释肥料标准(GB/T23348-2009)要求。生物质炭组分含量变化对包膜缓释肥缓释效果影响最大。生物质炭与膨润土、煤炭腐殖酸相互作用在肥芯外形成紧致膜层可能是制备的炭基缓释肥具备高效缓释性能的主要原因。 (3)以秸秆生物质炭和炭基缓释肥为试材,通过盆栽和大田实验,初步考察了炭基缓释肥施用对稻田氮素流失与水稻产量的影响。大田实验结果表明,与CK相比,SRFA的施用可以使水稻产量增加7.7%。人工模拟降雨实验结果表明,在相同雨量条件下,与对照相比,炭基缓释肥施用可削减径流总氮流失量27.3%-56.6%。通过对大田施肥后田面水的总氮浓度进行多项式拟合,CK的二次项系数0.0329SRFA的二次项系数0.0188,表明与CK相比,SRFA可以缓慢释放养分,有利于降低稻田氮素养分流失风险和水稻增产。
[Abstract]:Compared with traditional fertilizer, coated controlled release fertilizer can effectively reduce soil nitrogen loss. However, most of the coating materials are polymeric polymers, which are difficult to be degraded and accumulated, and can easily destroy soil structure for long term use. Therefore, it is a hotspot in this field to seek new sustained-release coating materials and prepare environmentally friendly sustained-release fertilizer. On the other hand, rice straw resources are abundant in China, but straw returning often promotes methane emissions. Biomass carbon has the characteristics of high stability and strong nutrient retention, and has the basic requirements as the coated material of slow-release fertilizer. If rice straw carbonization can be used to produce slow-release fertilizer, it will undoubtedly provide a new technical approach for the utilization of rice straw and the production of environment-friendly slow-release fertilizer. It will also contribute to the prevention and control of agricultural ecosystem non-point source pollution and the reduction of carbon sequestration in agriculture. Based on this, the pilot production experiment of straw biomass carbonization was carried out by using autoignition internal heat carbonization furnace and rice straw as raw material, and straw biomass carbon was used as main material by orthogonal test. The effects of carbon-based slow-release fertilizer on rice production and nitrogen loss in paddy field were tested in pot and field experiments. The main results are as follows: (1) the effects of air intake and residence time of blower on the carbonization yield and carbon content of biomass were investigated with the help of spontaneous combustion internal heat carbonization furnace with independent intellectual property rights and rice straw as test material. The results showed that the biomass carbon prepared under the conditions of air intake 2600m3/h and residence time 1 h was suitable for the preparation of carbon-based slow-release fertilizer. Under these conditions, after carbonization of rice straw at 400-500 鈩，

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