Synthesis and Performance of Polyurethane Coated Urea as Slow/controlled Release Fertilizer

Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 lam were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.

Study on the Rapid Method to Predict Longevity of Controlled Release Fertilizer Coated by Water Soluble Resin

The study discussed the rapid method to test and predict the longevity of controlled release fertilizers （CRFs） coated by water soluble resin by using the short-term leaching under higher temperature. Pure water dissolving incubation and higher temperature leaching were used to study the patterns of the nutrient release of the CRFs. The correlation analysis between the days at 25℃ and the hours at 80℃ of Trincote 1 and Trincote 2 for the same cumulative release rates were conducted. Patterns of cumulative nutrient release curve followed one factor quadratic regression equation at each given temperatures, and each of relative coefficient was bigger than 0.995. As the temperature increased, nutrients release of the CRFs increased. The longevity of resin coated CRFs were predicted by use of both the cumulative nutrients release equation at 80℃ and the regression equation of release time needed for the same cumulative release rates between 25 and 80℃. There were only 0.3-6.9% relative errors between the tested longevity and predicted one. In conclusion, the longevity of resin coated CRFs could be predicted more quickly and precisely by use of the higher temperature short-term leaching method than that of the traditional differential release rate. The longevity of resin coated CRF could be rapidly and precisely predicted in a few hours by application of the higher temperature shortterm leaching method.

Shifts in soil bacterial communities induced by the controlled-release fertilizer coatings

Coated controlled-release fertilizers （CRFs） have been widely applied in agriculture due to their increased efficiency. However, the widespread and a lot of coated CRFs application may leave undesired coating residues in the soil due to their slow degradation. Limited information is available on the effects of substantial residual coatings on the soil bacterial community. By adding 0, 5, 10, 20, and 50 times quantities of residual coating from conventional application amount of resin and water-soluble coated CRFs, we studied the responses of soil properties and bacterial community composition to these two residual coatings in black soil. The results showed that the resin and water-soluble coatings did not essentially alter the properties of black soil or cause dramatic changes to bacterial diversity within the test concentration range. The residual resin and water-soluble coatings also did not distinctly alter the relative abundance of the top ten bacteria at phylum level. Heatmap results suggested that the treatments were basically clustered into two groups by concentration rather than types of coating material. Pearson correlation analysis showed that the Simpson＇s diversity index of the bacterial community was significantly correlated with microbial biomass carbon （MBC, r=0.394, P〈0.05）, and the richness index abundance-based coverage estimator （ACE） of the bacterial community was significantly correlated with microbial biomass nitrogen （MBN, t=0.407, P〈0.05）. Overall, results of this study suggested that substantial residual resin and water-soluble coatings with 0-50 times quantities of residual coating from conventional application amount of coated CRFs did not generate obviously negative impacts on the bacterial community in black soil.

In situ polymerization coating and characteristics of coated NPK compound fertilizer

Controlled release NPK compound fertilizers were prepared by means of in situ polymerization of monomers on the surface of fertilizer granules at room temperature. Methacrylate, α-methyl acrylic acid, and ethylene dimethylacrylate were used as monomers, Dibenzoyl peroxide as initiator, and cobalt naphthenate, and triethyl amine as promoters. The structures of coating materials were characterized by IR spectra. The thermogravimetric analysis result indicated that the coating materials were of good thermal stability. The mean thickness of single coating measured with screw gauge was ca. 140 μm. The morphologies of uncoated and coated fertilizer granules analyzed by using scanning electron microscopy were changed from porosities and gullies to hills and plain. The release rate of coated compound fertilizers in water could be controlled by the hydrophicity and thickness of coating. The increase in coating hydrophicity caused the increase in release rate of fertilizer. The increase in thickness of coating slowed the release rate.

Development and Application of Coated Fertilizer in Japan

The fertilizer industry faces a continuing challenge to improve its products to increase the fertilizer use efficiency and to minimize any possible adverse environmental impact.For this purpose,studies on the development of coated fertilizers have been done all over the world.In this paper,we are to introduce our coated urea“MEISTER”as the sophisticated fertilizer,with explaining the features and applications in actual fields.“MEISTER”is the coated urea with a mixture of polyolefin and silicate mineral.“MEISTER”has two releasing types.One is the linear type.Another is the sigmoidal type.Release of nitrogen from“MEISTER”mainly depends on temperature which allows precise prediction of nutrient release.Application experiments for rice,Chinese cabbage and long onion are introduced in this paper.Every experiment shows single basal application is possible by using“MEISTER”with keeping yield and high nitrogen recovery.Coated fertilizers show accurate release control of nutrients.The use of coated fertilizers brings:(a)efficient use of fertilizer resources,(b)reduction of environmental load by fertilizer,(c)labor saving.Thus applying coated fertilizers is definitely smart fertilization technology in agriculture.Coated fertilizers seem to closely meet the requirements of an ideal fertilizer.The problem is its high price compared to the normal rapid soluble fertilizer.Unit price of coated fertilizer is expensive on the surface,though total application cost of coated fertilizers is often cheaper than the cost of rapid soluble fertilizers.This sometime disturbs the spread of coated fertilizers.So,we have been trying to make an effort to reduce production cost and doing application enlargement trials of coated fertilizers for becoming more widespread.Through those studies and development,we believe coated fertilizers will contribute to agriculture more in the world.

Recent Advances on the Technologies to Increase Fertilizer Use Efficiency

To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relatively low FUE and serious losses of nutrients. Recent advances of the technologies to increase FUE are reviewed in this article. These include site-specific and real-time nitrogen management, non-destructive quick test of the nitrogen status of plants, new types of slow release and controlled release fertilizers, site-specific nutrient management, and use of urease inhibitor and nitrification inhibitor to decrease nitrogen losses. Future outlook in technologies related to FUE improvement is also discussed.

聚乙烯醇/壳聚糖膜制备及其包膜尿素特性

为解决传统肥料养分利用率低,以及一般聚合物包膜肥料的膜材料难以降解、养分释放速率不可控等问题,该研究以聚乙烯醇(PVA)为膜基材,通过与壳聚糖(CS)共混、使用戊二醛(GA)交联、添加纳米SiO_(2)3种不同的方式,制备了3种膜:PVA/CS膜、PVA/CS/GA膜、PVA/CS/GA/纳米SiO_(2)膜,此外,制备了纯PVA膜作为对比。对4种膜进行了吸水率(Q)、生物降解性(De)、养分渗透系数(Ps)等表征,结果表明:CS的添加提升了膜的生物降解率,GA交联可以延缓膜在土壤中的生物降解速率,而纳米SiO_(2)的添加对膜的生物降解性影响不大,总体来说4种膜都显示出良好的生物降解性(77 d内的生物降解率在30%~60%);相比于PVA膜,PVA/CS、PVA/CS/GA和PVA/CS/GA/纳米SiO_(2)膜的吸水率分别降低43.00%、68.79%和82.73%;相比于PVA/CS膜,PVA/CS/GA和PVA/CS/GA/纳米SiO_(2)膜的养分渗透系数分别降低48.51%和57.59%,说明CS的添加、GA的交联和纳米SiO_(2)的添加都增强了PVA膜的疏水性。将4种膜液通过转鼓包衣机包覆在尿素颗粒表面制得了4种包膜尿素(PCU)颗粒(PCU-PVA、PCU-PVA/CS、PCUPVA/CS/GA和PCU-PVA/CS/GA/纳米SiO_(2)),分别使用土埋法测定和数学模型拟合了氮素释放行为,结果显示4种PCU的氮释放量达到90%时所需的时间分别为5、11、23、28 d;氮素释放行为符合一级动力学模型,释放速率常数(k)依次减小,分别为0.3654、0.2333、0.1127、0.0926,且与膜的养分渗透系数(Ps)呈线性关系,相关系数(R2)为0.9991。该研究提供了系列生物降解性能良好、养分释放速率可控的聚乙烯醇/壳聚糖膜材料,并成功地应用于包膜尿素颗粒的制备,更方便和有效地指导PCU的施用。

植物油包膜控释氮肥在间作玉米-大豆上的施用效果研究

为考察新型植物油包膜控释氮肥对间作玉米-大豆的产量、经济效益、肥料利用率等方面的影响,开展了田间小区试验。试验以不施氮肥(CK)、施用普通尿素(PU)处理为对照;植物油包膜控释氮肥施肥量为全量、减量20%、减量30%等3种,控释氮占总氮量为60%、40%等2种,共设置4个处理。结果表明,在玉米试验中,与PU处理相比,控释氮占总氮量60%的全量、减量20%处理的产量分别显著增产14.70%、7.49%,纯收入分别显著增加3192.80、2680.02元/hm2;控释氮肥处理的氮素利用率为50.14%~53.43%,差异显著。在大豆试验中,与PU处理相比,控释氮占总氮量60%的全量处理显著增产16.67%,纯收入显著增加2725.80元/hm2;控释氮肥处理的氮素利用率为54.12%~57.98%,差异显著。对于玉米-大豆间作栽培,建议全量或减量20%施用控释氮占总氮量60%的植物油包膜控释氮肥。

控释复合肥料的养分释放特性及其对不同花卉生长的影响

为探讨包膜质量分数分别为3%、4%、5%、6%的聚氨酯包膜控释复合肥料的养分释放特性和对花卉生长的影响,以市售的控释复合肥料为对照(CK)处理,开展了养分释放特征试验和以鸡冠花、鼠尾草为试验对象的盆栽试验及淋溶试验。结果表明:随着包膜量的增加,聚氨酯包膜控释复合肥料的养分释放率减小,有效延长了肥料的养分释放期;与CK处理相比,包膜量为4%、5%的聚氨酯包膜控释复合肥料分别显著提高了鸡冠花和鼠尾草的植株鲜质量;CK处理的淋溶液电导率(EC值)随时间延长不断减小,而聚氨酯包膜控释复合肥料淋溶液的EC值呈先上升后下降的变化趋势,可有效延缓土壤养分的流失。包膜量为4%~5%的聚氨酯包膜控释复合肥料可促进供试花卉的生长,有效提高肥料利用率,减轻对环境的污染。

聚氨酯微塑料和秸秆添加对滨海脱盐潮土有机碳矿化及其组分的影响

为模拟研究聚氨酯包膜控释肥微塑料残膜对土壤有机碳矿化及秸秆降解的影响,采集江苏省滨海地区脱盐潮土,进行为期35 d的室内培养试验。设置未添加物料(CK)、添加0.1%(质量分数w,下同)微塑料(T1)、0.3%微塑料(T2)、1%微塑料(T3)、1%秸秆(S)、0.1%微塑料+1%秸秆混施(T1+S)、0.3%微塑料+1%秸秆混施(T2+S)、1%微塑料+1%秸秆混施(T3+S)共8个处理,分析微塑料及其与秸秆混施条件下土壤有机碳矿化速率、有机碳组分和酶活性的变化特征。结果表明,T3、T1+S、T2+S、T3+S处理可显著促进土壤有机碳矿化,T1、T2处理对有机碳矿化无显著影响。与对照相比,T1、T2、T3处理显著提高了土壤累积矿化量,增幅为72.77%~80.00%。微塑料和秸秆添加处理均增加了土壤可溶性有机碳(DOC)、微生物量碳(MBC)、易氧化有机碳(ROC)含量。与对照相比,微塑料处理的DOC、MBC、ROC含量分别增加5.70%~57.43%、9.14%~41.92%和2.87%~57.34%;与单施秸秆相比,微塑料+秸秆处理的DOC、MBC、ROC含量在培养期间分别增加13.74%~75.82%、10.38%~60.19%和2.21%~34.76%。微塑料和秸秆添加处理均显著提高了土壤β-葡萄糖苷酶和过氧化氢酶活性。微塑料添加条件下土壤有机碳矿化速率与DOC、MBC、ROC含量及β-葡萄糖苷酶活性均呈显著正相关,而与土壤过氧化氢酶活性无显著相关性。结果表明,聚氨酯微塑料短期内可以增加土壤活性碳组分,促进土壤有机碳矿化,聚氨酯微塑料和秸秆对有机碳矿化和酶活性的影响具有交互作用。

包膜控释肥料研究进展

控释肥被认为是一种环境友好型肥料,不仅能控制养分释放速率与植物生长相匹配,而且能减少因肥料养分流失带来的农业面源污染。综述了国内外控释肥包膜材料研究的新进展,介绍了控释肥养分释放机制,分析了控释肥在农业生产中的应用效果和存在的问题,并对控释肥在农业上的应用前景进行了展望。

“墨翠”腐殖酸钾复合肥在水稻上的应用效果研究

为明确腐殖酸钾复合肥(腐殖酸螯合长效型)在华南地区双季稻上的应用效果以及为水稻高效施肥提供技术支撑,在广东省台山市海宴镇仑定村开展了腐殖酸钾复合肥在水稻上的应用效果试验,共设3个处理,试验过程中对水稻农艺性状、产量及土壤养分含量进行监测和分析。结果表明,“墨翠”腐殖酸钾复合肥(24-10-16)处理在推荐施肥用量范围内,水稻分蘖数高于其他2个处理,株高、有效穗、平均产量均高于农户习惯施肥即彩虹包膜双控控释肥(23-6-21)和不施肥处理,差异达显著水平(P<0.05)。水稻经济效益和经济系数依次为“墨翠”腐殖酸钾复合肥(24-10-16)处理>不施肥处理>农户习惯施肥即彩虹包膜双控控释肥(23-6-21)处理,但各处理之间未达到显著差异水平。与农户习惯施肥即彩虹包膜双控控释肥(23-6-21)处理相比,“墨翠”腐殖酸钾复合肥(24-10-16)处理水稻增产11.54%,产值增加1717.1元/hm2。“墨翠”腐殖酸钾复合肥(24-10-16)处理对减缓土壤p H值下降、调节和稳定土壤p H值有一定效果。腐殖酸钾分解后释放植物所需的营养元素对水稻生长具有积极作用。腐殖酸钾复合肥在华南地区可实现水稻的一次性施肥。

提高肥料利用率技术研究进展

如何提高肥料利用率、减少由于肥料损失带来的环境污染是长期以来全球共同关注的课题。针对我国肥料利用率低、氮肥损失严重的现状,本文综述了除传统提高肥料利用率技术以外的几项其它技术的最新研究进展,主要包括应用实时、实地氮肥管理技术快速、无损检测作物氮素营养状况,进行作物推荐施肥;研发新型缓/控释肥料,调控肥料养分的供应;运用农田养分精准管理技术,因地制宜、精细准确地施用肥料;通过脲酶抑制剂或硝化抑制剂,有效地抑制NH3挥发和NO3--N淋溶损失等。并对今后提高肥料利用率技术进行了展望。

有机高聚物包膜控释肥氮释放特性的测定与农业评价

采用水浸泡法对 3种有机高聚物包膜控释肥Osmocote 、MEISTER 和山东农业大学包膜肥试样的养分溶出特征进行了系统比较测定 ,研究了 3种控释肥初期溶出率、微分溶出率和养分释放期的特征与差异 ;研究了温度对3种包膜控释肥氮素释放率与释放期的影响 ;通过土壤施用包膜控释肥的盆栽试验 ,测定水稻全生育期的吸氮量和产量。并将 2种测定方法综合分析 ,用于评价不同控释肥的作用适应性 。

土壤硝态氮淋溶及氮素利用研究进展

农业生产中氮肥的不科学施用,在一定程度上造成环境污染,而硝态氮淋溶则是水体环境质量恶化的重要影响因素,也成为氮素损失研究中的热点问题。综述了近年来国内外在土壤硝态氮淋溶方面的研究进展,提出氮肥施用量多寡以及土壤灌溉和降雨是导致硝态氮淋溶的重要因素,总结了根据土壤质地和矿物组成调整氮肥施用,合理耕作,水分管理,生化抑制剂的合理添加以及新型高效缓控释肥料的施用等措施是减少土壤硝态氮淋溶,提高氮素利用率的有效途径。

硫膜和树脂膜控释尿素对水稻产量、光合特性及氮肥利用率的影响

本试验以控释期为90d的硫膜(SPCU)和树脂膜(PCU)控释尿素为材料,通过盆栽试验,研究了硫膜和树脂膜控释尿素对水稻产量、光合特性及氮肥利用效率的影响。结果表明,与普通尿素(U)一次基施相比,控释尿素各处理均能显著提高水稻子粒产量、氮肥表观利用率和农学效率,增幅分别达15.1%～51.4%、64.5%～141.1%和5.4～18.2 kg/kg;显著提高水稻生育中后期叶片净光合速率;提高水稻生育中后期的SPAD值。与普通尿素分次施用相比,树脂膜控释尿素及硫膜控释尿素和普通尿素以7∶3比例一次性施入的处理能显著提高水稻子粒产量、氮肥农学效率以及水稻收获后的土壤全氮和碱解氮含量,其增幅分别为7.9%～31.7%、3.3～13.0 kg/kg、2.2%～17.6%和13.2%～22.0%;显著提高叶片中后期的净光合速率,且以树脂膜控释尿素100%一次基施的处理最高。施用树脂膜控释尿素的各处理较普通尿素均能显著提高水稻的氮肥生理效率。树脂膜控释尿素比硫膜控释尿素表现出更好的水稻增产效应和氮肥利用效率,更能有效延缓叶片衰老,实现水稻氮素的高效利用。

包膜控释肥养分释放特性评价方法的研究进展

控释肥已成为国内外肥料研究的热点 ,但是评价控释肥养分释放特性的方法研究相对滞后 ,至今没有较为完善的方法和统一的测试标准。本文综述了包膜控释肥养分释放特性的现有评价方法 :水中 (或溶液 )溶出率法、土壤溶出率法、扩散率法、渗透率法、电超滤法和同位素示踪法等 ;评述了各种方法的优缺点及改进途径 ;

包膜控释肥料在土壤中养分释放特性的测试方法与评价

在土壤培养基础上,着重研究了包膜控释肥料养分释放率的三种测定方法以及在土壤中测得的包膜控释肥料养分释放率与在水中测得的养分释放率间的相关性。结果表明,在土壤培养中,采用肥料养分化学测定法、肥料养分称量法和土壤无机氮增量法都能直接或间接表征包膜控释肥料在土壤中的养分释放率及其相关性状。包膜控释肥料在土壤与水两种体系中所测得的养分释放率之间相关性显著,其相关关系符合一元一次线型回归方程,相关系数(r)大于0.920。

包膜肥料养分控释机理研究进展

利用胶囊技术将易水溶性肥料包被起来是提高肥料利用率和减少施肥环境风险的一个重要手段 .在广泛收集国内外有关包膜肥料研究的基础上 ,探讨了包膜肥料养分控释的原理、过程和特征 ,概述了影响包膜肥料养分控释的因素和包膜肥料养分控释的数学模拟研究 。

聚合物/膨润土复合控释材料的应用研究

用聚合物/膨润土复合材料与肥料混合制备混合型缓/控释肥和用复合材料包裹尿素制备包膜型缓/控释肥进行盆栽试验。结果表明,聚合物和膨润土都具有控释作用,二者复合具有更好的控释效果。几种混合型缓/控释肥处理的玉米生物量均较对照有显著提高,以添加含膨润土0 5倍(相对于聚合物质量)的复合材料配制的缓/控释肥效果最好。几种包膜型缓/控释肥处理的玉米生物量较对照有所提高,差异达显著水平,以含膨润土2倍的复合材料制备的缓/控释肥效果最好。