【作者】 段路路；

【导师】 张民；

【作者基本信息】 山东农业大学 ， 土壤学， 2009， 博士

【摘要】 随着人口—资源—环境问题的日渐突出,农业生产中为保障高产而对肥料的应用愈加关注。在肥料的施用中提高肥料利用率、降低资源浪费、减少环境污染是保障土壤资源可持续利用的目标和关键。缓控释肥料可以显著提高肥料的利用率、减少养分的挥发和淋溶损失、减轻施肥对环境的污染、改善作物的生长发育状况、提高作物的产量和品质,因而受到了研究人员的广泛关注。生产和施用缓控释肥料已经成为目前化肥工业发展的主要趋势之一,也是发展现代农业、实施可持续发展战略的必然要求。缓控释肥料能提高养分利用率是其养分释放特性包括养分释放率和释放期以及养分释放与作物对养分吸收的同步性所决定的,因此,对其释放特性的研究和评价方法的建立是评价缓控释肥料质量和性能的关键环节。本研究采用水浸提法、饱和盐溶液蒸汽压法、土壤培养法和肥料填埋法,探讨了不同种类缓控释肥料养分释放机理,并按照缓控释肥料行业标准(HG/T 3931-2007)、硫包衣尿素行业标准(HG/T 3997-2008)和欧洲标准化委员会(CEN)推荐的控释肥料和硫包衣尿素评价标准,对15种缓控释肥料的养分释放特性进行了研究和评价。采用扫描电镜和红外光谱分析,对缓控释肥料的微观结构进行了研究。同时,采用盆栽和大田试验,评价了缓控释肥料养分释放特性与作物需肥规律的吻合性。主要研究结果如下:1.温度是影响缓控释肥料养分释放的主要因素。对于热塑性树脂包膜尿素、热塑性树脂包膜复合肥、热固性树脂包膜复合肥、硫包衣尿素、异丁叉二脲来说,温度越高,养分释放速率就越快,释放期就相对越短。聚合物包膜控释肥在水中的释放曲线多为“S”型,SCU为“破裂式释放”,IBDU的释放曲线呈倒“L”型。在不同培养温度条件下氮素释放率与时间的关系可用一级动力学方程Nt=No(1-e-kt)、Elovich方程Nt=a+blnt和抛物线方程Nt=a+bt0.5表征,在25℃和40℃时,以一级动力学方程拟合效果最好。定量描述氮素养分释放的动力学方程中以一级动力学方程更具有实效性。聚合物包膜复合肥的养分释放规律为氮素释放速率最快,其次是钾,磷素释放速率较慢。2.包膜控释肥料的养分释放是由包膜内外水蒸汽压差引起的,其释放速率常数k随着水蒸汽压差的增大而增大。蒸汽压差越大,养分释放率越大,反之越小。在同一水蒸汽压下,包膜肥料的养分释放率随着培养时间的延长而增大;相同的培养时间,养分累积释放率表现为H2O>KH2PO4饱和溶液>KCl饱和溶液。包膜控释肥料膜内外水蒸汽压差是控制养分释放速率快慢的根本因素。3.土壤含水量对缓控释肥料养分释放速率有较大的影响。当土壤含水量在田间持水量之内,随着土壤含水量的增加,养分释放加快。包膜尿素在不同土壤含水量下拟合曲线的相关系数在0.9740～0.9972之间,标准误在0.0015～0.0022之间,达极显著水平(ρ=0.0001)。对于包膜复合肥来说,供试样品CRF1和CRF2在各培养时期内氮素释放率均随着土壤含水量的增大而增大。对于硫包衣尿素来说, SCU在土壤培养中的释放率要高于其在静水浸提中的释放率。而异丁叉二脲在水中的释放率始终快于土壤培养中的释放率。4.扫面电镜试验表明,包膜材料不同,包膜后在肥料颗粒表面成膜的结构不同。热塑性树脂膜表面有微小的孔隙,这些微孔是养分释放的通道;热固性膜表面都比较致密,都存在不同的固体颗粒突起,很难看出微孔的存在。硫包衣尿素膜表面非常光滑,包膜材料之间的排列和堆积比较致密。从断面照片可以看出,供试样品PCU1、CRF1、CRF2、Nutricote、Osmocote和SCU1的膜厚度分别为59.5μm、58.6μm、41.4μm、107μm、46.3μm和55.1μm,同时六种肥料的膜厚度均匀,包膜质量较好。5.红外光谱分析试验表明,不同膜质材料的红外光图谱有明显差异。两种热塑性树脂包膜复合肥料(CRF1和Nutricote)的膜材料在波长3447 cm-1、2919 cm-1、2850 cm-1、670 cm-1附近都有红外吸收,说明两种膜材料有一定的相似性,同时比较两者的红外谱图也可见波谱的相似处;两种热固性树脂包膜复合肥料(CRF2和Osmocote)的谱图有很大的相似性,不同的是Osmocote含有脂肪族一元酸的官能团;而SCU1的红外光谱图不仅显示SCU1膜中除无机硫占大多数以外,还含有类似氧化乙烯聚合物或聚乙烯蜡等添加物。6.采用25℃常温浸提法测定与100℃快速浸提法测定,后者的养分释放率加快。可用100℃快速浸提法建立预测缓控释肥料在常温下(25℃)的释放期的回归方程(一元二次方程,相关系数大于0.98),预测值与实测值相差1～3d。对于25℃常温浸提法测定释放期分别为66d和84d的包膜控释复合肥CRF2和CRF3,用100℃电导率法预测的养分释放期分别为65d和81d,相对误差小于3.5%,可见电导率法也可以准确快速地预测包膜控释复合肥料的养分释放率和释放期。用初期养分释放率、平均释放率和养分释放期等参数,可用于缓控释肥料的综合评价。7.缓控释肥料在水、土两种介质中的养分释放特性有一定的关系,4种缓控释肥料在水浸法和土壤培养法中的养分释放特性均可用二项式方程进行拟合,说明两种方法存在一定的相关性。因此,在对缓控释肥料进行农业评价时,应在实验室水浸法的基础上,进行土壤培养试验,进而测定作物的养分吸收量,并结合作物生长与产量的结果加以具体分析。本研究结果表明树脂包膜控释肥料可以在相同温度下用水中测定的释放率预测在土壤中的养分释放率。8.控释肥料的养分释放可以通过制作工艺的调整与改进使其与作物对养分的吸收相同步,达到使作物增产和增效的作用,CRF1、CRF2两处理的油菜养分吸收量和生物量显著高于其他处理,以CRF2处理为最高,并且CRF1、CRF2的养分释放特性更接近油菜的需肥规律。通过对肥料种类与作物匹配性的评价与预测,并将两者结合起来,可以制造出适合各种作物生长发育的专用控释肥料。更多还原

【Abstract】 The problem of population-resource-environment becomes more and more prominented. It should been pay more attention to the using of fertilizer in order to enhance the output of soil. The problems such as how to enhance the efficiency of fertilizer,how to reduce the waste of resources,how to lessen the environment pollution ,how to ensure soils and so on are the targets for fertilizer research.The efficiency of fertilizer have been improved evidently, loss and volatilization of nutrition elements hav been reduced, waste of resources have been lightened,product quality and crop output have been enhanced markedly by applied slow and controlled-release fertilizers,so many experts think highly of them. The production and use of slow and controlled-release fertilizers are one of the main trends for the development of chemical fertilizers at present, and are necessary need for the development of modern agriculture and sustainable development stratagem.“Water extraction method”“vapor pressure method in saturated salt”“soil incubation method”and“fertilizer embedding method”were used to discuss mechanism of slow and controlled-release fertilizers. Nutrient release characteristics of fifteen different kind of slow and controlled-release fertilizers were evaluated according to the chemical industry standard of slow/controlled-release fertilizer (HG/T 3931-2007), the chemical industry standard of sulfur coated urea (HG/T 3997-2008)and the standard recommended by the Committee of European Normalization (CEN) using water extraction method and soil incubation method. The membrane microstructures of slow and controlled-release fertilizers were studied by scanning electron microscopy and infrared spectra. Meanwhile, the relationship between fertilizer release rates and nutrient requirements of plant were tested in a pot experiment and a field experiment. The main results were summarized as follows:1. Temperature was the main factor which affected the nutrient release of slow and controlled-release fertilizers. These slow and controlled-release fertilizers could include ploymer coated urea, risen coated compound fertilizers, polymer coated compound fertilizers, sulfur coated urea and Isobutylidene diurea, and the higher the temperature was , the quickly the release rate of them was. In water, the nutrient release curves in water were“S”pattern for CRF1 and CRF2, burst release for SCU, and reverse“L”pattern for IBDU. The dynamics of nitrogen release rate could be quantitatively described by three equations: the first-order kinetics equation (Nt=No(1-e-kt)), Elovich equation (Nt=a+blnt) and parabola equation (Nt=a+bt0.5). However, the imitation of the first-order kinetics equation was the best at 25℃and 40℃. So, the imitation of the first-order kinetics equation was the most practical for the release of nitrogen release. Besides, the nitrogen release of coated compound fertilizers was the fast, next was potassium, and phosphorus release was the slowest.2. The differences of inside and outside water vapor pressures arose to the nutrient release of coated controlled-release fertilizers. The constant k increased with the water vapor differential pressure increased. The bigger the water vapor differential pressure, the higher the nutrient release rate. Under the same water vapor pressure, the nutrient release rate would grow bigger when the time was extended, and at the same time, the order of nutrient cumulative release rate was H2O>KH2PO4 saturted solution>KCl saturted solution. So the base factor of controlling the nutrient release rate was the differences of inside and outside water vapor pressures.3. Soil water content would influence the nutrient release rate of slow and controlled-release fertilizers. When the soil water content was under the field moisture capacity, the nutrient release would be speedy with the increase of soil water content. For coater urea, the correlation coefficient of fittingcurve was between 0.9740 and 0.9972, and the standard error would be between 0.0015 and 0.0022, so the fitting curve would reach best conspicuous level. For coated compound fertilizers, the nitrogen release of CRF1 and CRF2 would increase with the increase of soil water content at different time. For SCU1, the release rate in soil was higher than that in water, but opposite phenomenon occurred for IBDU.4. Scanning electron microscope test indicated that when the material of coat was different, the structure of membrane was different. The surface of thermoplast had minim pore which was the channel of the nutrient release. The surface of polymer was relatively collapse, and there was different solid particle, so minim pore could not see clearly. The surface of SCU was very smoothing, so arrange and deposit of material were relatively compactness. It could be seen that from fracture the film thickness of PCU1 CRF1 CRF2 Nutricote Osmocote and SCU1 were 59.5μm 58.6μm 41.4μm 107μm 46.3μm and 55.1μm. Besides, the film thickness of six fertilizers was uniformity, and the quality of coat was preferably.5. Infrared spectra test indicated, the infrared spectra of different coated material had distinct variance. For CRF1 and Nutricote, they had infrared absorption at 3447 cm-1 2919 cm-1 2850 cm-1 and 670 cm-1, so the material of the two fertilizers had some similarity. For CRF2 and Osmocote, the spectra of them also had prodigious similarity, but Osmocote had functional group of aliphatic hydrocarbons. The infrared spectra of SCU1 showed that there were ont only lots of inorganic sulfur but also addition such as ethylene epoxide and polyethylene wax.6. Nutrition release was accelerated when temperature of the solution in the water extraction method was raised from 25℃to 100℃. The regression equation for prediction and forecast of the 100℃fast extraction method fit a quadric equation in one variable with a correlative coefficient being < 0.98, and could be used to quickly and precisely predict release duration of slow/controlled fertilizers. The difference between the measured value and predicted one was only one to three days. Besides, electric conductivity measurement could also be used to quickly and precisely predict nutrient release rate and duration. By using the electric conductivity measurement at 100℃, the release duration of CRF2 and CRF3 was predicted to be 65days and 81days, less than 3.5% in difference from their measured duration of 66 days and 84. Parameters, like initial nutrient release rate, mean release rate, and release duration, could be used for integrative evaluation of slow- and controlled- release fertilizers.7. The nutrient release characteristics of the four fertilizers in“water extraction”and“soil incubation”all fit binomial equations, suggesting there was some correlation between the two methods. Therefore, when the agriculture evaluation of slow and controlled-release fertilizers was carried out,“soil incubation”test should be take on the base of“water extraction”test, and also the nutrient absorptivity of plant should be measured, and then the plant growth and output should be analysis. This study indicated that the release rate in soil could be predicted by the releasee rate in water at the same temperature.8. Slow and controlled-release fertilizers are fertilizers containing a plant nutrient in a form which either delays its availability for plant uptake and use after application, or which is available to the plant significantly longer than a reference“rapidly available nutrient fertilizer”. The nutrient uptakes and biomass of plants treated with CRF1 and CRF2 were significantly higher than other treatments, among which CRF2 the greatest. Nutrient release curves of CRF1 and CRF2 accorded with nutrient requirements of canola more closely. Meanwhile, special purposes controlled-release fertilizers which suit the growth and development of plants could produce by evalution and predict of fertilizer kind and plant matching.更多还原