Effects of an environmental friendly slow-releasing woodchip fertilizer on cabbage production

Wood from three tree species was used for making slow-releasing woodchip fertilizer. Fertilizer made from Populus tomentiglandulosa retained the highest amounts of N （29.04%）, P205 （26.03%） and K20 （16.93%）. On the other band, woodchip fertilizer made from Pinus koraiensis retained the lowest amounts of N （26.22%）, P205 （21.80%） and I（20 （14.49%）. A field experiment was performed in a 50 m^2 experimental plot at Gangwon Agricultural Research and Extension Services, Chuncheon, Korea from August to November 1999. The effects of a general fertilizer along with compost and slow releasing woodchip fertilizer without compost on the cabbage production were observed. Cabbage production parameters, such as top height, head weight, head height, head width, number of outer and inner leaves, leaf width and head length, increased in the field where Larix kaempferi woodchip fertilizer was added as a basal dose. The result showed that the woodchip fertilizer made from Pinus koraiensis had faster releasing properties compared to other woodchip fertilizers. Without adding any compost in the woodchip fertilized field, woodchip fertilizer showed a superior outcome over a general chemical fertilizer. Although the amount of woodchip fertilizer was larger compared to that of a chemical fertilizer, it increased cabbage production.

Effect of Slow and Controlled Release Fertilizers on the Yield and Nutrient Use Efficiency of Hot Pepper in Qiu-bei

[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper（Capsicum frutescens L.）as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection.

Effects of Slow Release Fertilizer on the Yield and Nutrient Use Efficiency of Carnation and Its Environmental Protection Effect

[Objective] The aim was to study the effects of slow release fertilizer on the yield,economic benefit and nutrient use efficiency of carnation and environmental pollution.[Method] Taking carnation（Dianthus caryophyllus）as research object,the application effect and environmental protection effect of slow release fertilizer on carnation were discussed through field plot test.[Result] The main agronomic characters of carnation improved after the application of slow release fertilizer;compared with Conv-F treatment,the yield of carnation with slow release fertilizer increased by 18.67%-20.83%,and its economic benefit increased by 105 500 yuan/hm2,while the ratio of output to input improved by 74.29%;under the same NPK ratio and nutrient amount,the yield,economic benefit and ratio of output to input of carnation after the application of slow release fertilizer increased by 2.11%,14 800 yuan and 16.2%,respectively;besides,the application of slow release fertilizer improved the nutrient use efficiency of carnation,and N,P and K nutrient use efficiency in Opt-F-0.7% treatment increased by 13.88%,8.57% and 30.14% compared with Conv-F treatment.[Conclusion] Slow release fertilizer could not only reduce the waste of fertilizer resources and improve fertilizer use efficiency but also decrease the pollution caused by nutrient loss,which had important practical significance for protecting ecological environment and promoting the sustainable development of agriculture.

Preliminary Discussion on Research Progress and Prospect of Slow Released Fertilizers

Slow/controlled release fertilizers （SRFs/CRFs） have been paid more at- tentions by the researchersin recent years. In this paper, the application effects and methods, types, current problem and development prospect of SRFs/CRFsboth at home and abroad were reviewed. The production principles and processes of urea- formaldehyde slow release fertilizers were introduced; and It is suggested that the urea-formaldehyde slow release fertilizers show great development to ease energy and environment pressure.

Application Effect of Water-absorbent Slow Release Nitrogen Fertilizer in Latosol

[Objective] A new-type water-absorbent slow release nitrogen fertilizer（WASRNF） was produced through polymerization reaction. Its physicochemical property and application effect in latosol were studied. Feasibility of using WASRNF to improve the serious problems of latosol in rubber planting area in Hainan Island including vulnerable nutrient, free-running fertilizer and water was studied. [Result] The results showed that raw materials of WASRNF, urea and water-retention material formed co-polymer through hydrogen-bond interaction that the WASRNF contained many hydrophilic groups. The p H value of WASRNF is near neutral and its water absorbent rate in tap water could reach 167.17 g·g-1. The water absorbent rates in latosol leach liquors with water/soil ratios of 1：5, 1：10 and 1：20 were 104.66, 122.93 and 145.38 g·g^-1, respectively. The maximum water holding ratio of latosol increased by 23.72%, 30.89% and 39.68% when 0.5%, 1% and 2% WASRNFs were added to latosol, and water evaporation rate of latosol decreased efficiently. Compared with common urea, WASRNF could slow down the leaching rate of nitrogen and the initial leaching amount was only 22.17% of the total amount. [Conclusion]The results indicated that WASRNF in latosol had strong water absorption and water-retention abilities in addition to the good slow release effect, and could efficiently decrease nutrient loss, increase utilization ratio of water and fertilizer and promote interaction between water and fertilizer.

Differences of yield and nitrogen use efficiency under different applications of slow release fertilizer in spring maize

Excessive or insufficient application of fertilizer has raised broader concerns regarding soil and environmental degradation.One-time application of slow release fertilizer (SF) has been widely used to reduce yield gap with potential maize yield and improve nitrogen use efficiency (NUE).A 2-year field experiment (2018–2019) was conducted to evaluate the effects of SF rates from 0 to 405 kg N ha^(–1) (named F0,SF225,SF270,SF315,SF360,and SF405) and 405 kg N ha^(–1) of common fertilizer(CF405) on the grain yield,biomass and N accumulation,enzymatic activities related with carbon–nitrogen metabolism,NUE and economic analysis.Results indicated that the highest grain yields,NUEs and economic returns were achieved at SF360in both varieties.The enzymatic activities related with carbon–nitrogen metabolism,pre-and post-silking accumulation of biomass and N increased with increasing SF rate,and they were the highest at SF360 and SF405.The grain yield at SF360had no significant difference with that at SF405.However,the N partial factor productivity,N agronomic efficiency and N recovery efficiency at SF360 were 9.8,6.6 and 8.9% higher than that at SF405.The results also indicated that the average grain yields,NUE and economic benefit at SF405 were 5.2,12.3 and 18.1% higher than that at CF405.In conclusion,decreasing N rate from 405 kg ha^(–1)(CF) to 360 kg ha^(–1)(SF) could effectively reduce the yield gap between realized and potential maize yields.The N decreased by 11.1%,but the yield,NUE and economic benefit increased by 3.2,22.2 and 17.5%,which created a simple,efficient and business-friendly system for spring maize production in Jiangsu Province,China.

Characteristics and Performance of Novel Water-Absorbent Slow Release Nitrogen Fertilizers

In this article, a research on the characteristics and performance of water-absorbent slow release nitrogen fertilizer （WASRNF） using infrared spectroscopy （IR）, scanning electronic microscopy （SEM）, differential scanning calorimetry （DSC）, and thermogravimetry analysis （TGA）, was present. The results indicate that the water absorbency and nitrogen analysis of WASRNF is 103 g g^-1 and 30%, respectively, and WASRNF exhibits approximately neutral pH and very low salt index. WASRNF is a copolymer of nitrogen fertilizer and super absorbent polymer （SAP） monomers which is formed through hydrogen bond interaction, and the molecule contains hydrophilic groups, which is responsible for the absorption and water retention capacity of the molecule. WASRNF is a gel that exhibits the ability to swell, but does not dissolve in water. WASRNF shows non-homogenous nature as a whole, but in local zone it is homogenous, the copolymer molecule shows chain network that is the physical structure responsible for absorption and retention of water in WASRNF. The water retained in WASRNF exists as free and nonfreezing bound and freezing bound water states, with the free and the nonfreezing water accounting for more than 95% of water retained in WASRNF, and the nonfreezing bound water for less than 5%. WASRNF functions in delaying the release of nitrogen from it, thereby serving a novel slow release nitrogenous fertilizer.

Effects of slow or controlled release fertilizer types and fertilization modes on yield and quality of rice

There is limited information about the influence of slow or controlled release fertilizer（S/CRF） on rice yield and quality. In this study, japonica rice cultivar Nanjing 9108 was used to study the effects of three different S/CRFs（polymer-coated urea（PCU）, sulfur-coated urea（SCU）, and urea formaldehyde（UF）） and two fertilization modes（both S/CRF and common urea（CU） as basal fertilizer, S/CRF as basal and CU as tillering fertilizer） on rice yield and quality. CU only was applied separately as control（CK）. Results showed that, rice grain yield, chalky kernel rate, chalky area, overall chalkiness, and the content of gliadin, glutenin, and protein, all showed the trends of UF〉PCU〉SCU within the same fertilization mode, and showed the trends of S/CRF as basal and CU as tillering fertilizer〉both S/CRF and CU as basal fertilizer within the same type of S/CRF. In contrast, the contents of amylose, amylopectin, and starch, as well as taste value, and peak and hot viscosity showed trends of SCU〉PCU〉UF, and the trends of both S/CRF and CU as basal fertilizer〉S/CRF as basal and CU as tillering fertilizer. Among S/CRF treatments and fertilization modes, taste values of cooked rice were positively correlated with amylose, amylopectin, and starch contents, as well as gel consistency, peak viscosity, hot viscosity, and cool viscosity, while negatively correlated with globulin, gliadin, glutenin, and protein contents. The types of S/CRF and fertilization modes are important for improving rice yield and quality. Compared to CK, higher yield and similar quality of rice was achieved with UF as basal and CU as tillering fertilizer, and similar yield with improved appearance and eating and cooking quality of rice was achieved with either both UF and CU as basal fertilizer, or PCU as basal and CU as tillering fertilizer.

Synthesis and Characterization of Suspension Polymerized Styrene-Divinylbenzene Porous Microsphere Using as Slow-Release-Active Carrier

Functional porous microspheres used for the slow release carrier of actives in cosmetics or pharmaceuticals were prepared by modified suspension polymerization of styrene （ST） with divinylbenzene （DVB） in the presence of toluene, cyclohexanol and heptane as porogenic diluents. The use of ultrasonic dispersion decreases the beads＇ size and improves the uniformity. The effects of the porogen mixture, DVB content and solvent extraction on the surface performance of the synthesized beads were studied. The microspheres were characterized by scanning electron microscopy （SEM） and BET surface area determination. It was found that a great proportion of the non-solvating porogen increases the pore diameter and the specific surface area. High DVB concentration also results in the great specific surface area and porosity. When the ratio of toluene/cyclohexanol is 1：2, DVB content is at the range of 40%-60% and methylene chloride was used as extractant, the beads with good spherical shape and pore size were obtained. The prepared porous microspheres were applied as active carriers and showed satisfactory slow release effect. Over 10h constantly sustained release was observed in vitro releasing test for hydroquinone-loaded microspheres. Great surface area promoted high concentration of released hydroquinone.

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.

Release Characteristics of Different N Forms in an Uncoated Slow/Controlled Release Compound Fertilizer

This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer （UCRF） and the N uptake and N-use efficiency by rice plants. Water dissolution, soil leaching, and pot experiments were employed. The dynamics of N release from the UCRF could be quantitatively described by three equations： the first-order kinetics equation [N1=N0 （1-e^-kt）], Elovich equation （N1=a ＋ blnt）, and parabola equation （N1=a ＋ bt^0.5）, with the best fitting by the first-order kinetics equation for different N （r= 0.9569^＊＊-0.9999^＊＊）. The release potentials （No values estimated by the first-order kinetics equation） of different N in the UCRF decreased in the order of total N 〉 DON 〉 urea-N 〉 NH4^＋-N 〉 NO3^-N in water, and total N 〉 NH4^＋-N 〉 DON 〉 urea-N 〉 NO3^--N in soil, respectively, being in accordance with cumulative amounts of N release. The constants of N release rate （k values and b values） for different N forms were in decreasing order of total N 〉 DON 〉 NH4^＋-N 〉 NO3^--N in water, whereas the k values were urea- N 〉DON 〉 NH4^＋-N 〉 total N 〉 NO3^--N, and the b values were total N 〉 NH4^＋-N 〉 DON 〉 NO3^--N 〉 urea-N in soil. Compared with a common compound fertilizer, the N-use efficiency, N-agronomy efficiency, and N-physiological efficiency of the UCRF were increased by 11.4%, 8.32 kg kg^-1, and 5.17 kg kg^-1, respectively. The ratios of different N to total N in the UCRF showed significant correlation with N uptake by rice plants. The findings showed that the first-order kinetics equation [Nt=N0 （l-e^kt）] could be used to describe the release characteristics of different N forms in the fertilizer. The UCRF containing different N forms was more effective in facilitating N uptake by rice compared with the common compound fertilizer containing single urea-N form.

Starch Modification for Slow Release of Herbicide Encapsulated with Concentrated Starch Paste

An attempt on starch modification has been made to increase the paste concentration of potato starch for reducing the energy consumption required for the encapsulation of herbicide within starch matrix by encapsulating 2, 4-D as model herbicide. The matrix behaviors were evaluated in terms of the herbicide content, capability of swelling in water, encapsulation efficiency, and the rate of herbicide released from the matrix. To increase paste concentration of starch for decreasing the energy consumption in dry process, potato starch was acidified before the encapsulation. However, the matrix prepared in such a way showed that it weakened the control to the herbicide encapsulated, which increased the rate of herbicide released from the matrix. By introducing covalent bonds among starch molecules, the problem with the control and release rate can be completely solved. Moreover, the effects of formaldehyde amount, medium pH, herbicide content, and particle size on the matrix behaviors and release rate were also investigated. The newly developed matrix shows low capability of swelling and slow release, and reduces water evaporation in dry process by about 40% during matrix preparation.

Production Technology and Application of Slow-Release Non-protein Nitrogen Extruded Feed Additive

Slow-release non-protein nitrogen feed has a large market demand. It has a long research history, but its production technology needs further improvement in order to realize the industrial production of slow-release non-protein nitrogen extruded feed. By designing the best formula and using chelating and emulsifying process, the slow-release non-protein nitrogen extruded feed additives were produced. This product increases milk yield and improves milk quality, thus increasing economic efficiency.

Screening of Slow Release Solvents for Plant Volatiles

[Objective] The paper was to study the slow release effects of eight common kinds of slow release solvents on n-hexane, and to provide a reference for the construction of slow release system of attractants or repellents synthesized by plant volatiles. [Method] The effect of slow release solvents on volatile quantity and release rate of n-hexane was compared by weight loss method. [Result] Under indoor natural conditions [(22±2) ℃,RH 50%±10%], the slow release effect of lubricating oil on n-hexane was the best, followed by liquid paraffin. The best ratio of slow release solvent(lubricating oil and liquid paraffin) and n-hexane was 5∶1 and the best mixing time was 3 h, which improved the slow release effects of n-hexane by6.3 and 4.7 times, and prolonged the half-life of n-hexane by 1.3 and 1.0 times, respectively. Slow release solvents mainly affected the post-half-life period of n-hexane, and the release rates of n-hexane mixed with lubricating oil and liquid paraffin were decreased by 10.4 and 7.7 times, respec-tively. During the half-life period, the release rates of n-hexane were decreased by 1.3 and 1.0 times, respectively. [Conclusion] Two kinds of slow release solvents with good slow release effect on volatile n-hexane are screened out, and the proportion and mixing time of slow release solvent and volatile are determined, which will provide technical support for the construction of plant volatile slow release system.

Effects of Different Slow-release Fertilizers on Growth and Yield of Ratooning Rice

The effect of slow-release fertilizer application on reducing the fertilization times of ratooning rice was explored by carrying out plot experiments using different slow-release fertilizer formulas.The results showed that compared with conventional fertilization of farmers(TCK),there were no significant differences in plant heights of the first rice crop and ratoon rice crop and the number of tillers was slightly increased,by applying different ratios and types of slow-release fertilizers,indicating that reducing fertilization times did not affect rice growth.Compared with the TCK,the yields of treatments T1,T2,T3 and T4 of slow-release fertilizers increased to a certain extent.The yield of the first rice crop increased by 14.7%,16.7%,23.5% and 17.5%,respectively,the yields of the ratoon rice crop increased by 6.3%,5.8%,7.4% and 8.1%,respectively,and the yields of the two rice crops increased between 10.8% and 16.1%,indicating that reasonable combined application of slow-release nitrogen and fast-acting nitrogen fertilizer could meet the nutrient requirements of ratooning rice at different growth stages,and the application of slow-release fertilizers could reduce the fertilization times of ratooning rice.Based on the combination of rice yield and slow-release fertilizer cost in the first rice crop and ratoon rice crop,the T 3 formula was preferred,that is,urea-formaldehyde slow-release nitrogen fertilizer was used as the base and tillering fertilizer,and polyurethane-coated slow-release nitrogen fertilizer was used as the panicle-sprouting fertilizer.

Studies on In Vitro Slow-Release Characteristics and Anticancer Effect of 5-Fluorouracil-Loaded Immuno-Nanoparticles

OBJECTIVE To investigate slow-release features of biodegradable anticancer 5-fluorouracil-loaded immunonanoparticles （5-FU INPs）, and to assess their tumor cell killing activity in vitro.METHODS The method of vibrating dialysis at a constant temperature, and first-order derivative ultraviolet spectrophotometry were used to determine the drug-releasing character of 5-FU INPs. The methyl thiazolyl tetrazolium （MTT） colorimetric method was employed to assay the killing activity of 5-FU INPs on 5 tumor cell lines at different phases.RESULTS The 5-FU INPs had a favorable slow-release function, with a tl/2 release time of 10.4 days. The 5-FU INPs had a rather strong lethal effect on 5 tumor cell lines resulting in a positive correlativity between the killing activity and the action time and amount of the drug released.CON＇CLUSION The drug disposition is uniform from the 5-FU INPs, and there is no impact on efficacy of the 5-FU during preparation and degradation of the 5-FU INPs. The 5-FU INPs have a favorable function for drug release, and can maintain an effective killing activity over a long period of time.

Comparison on the Pharmacokinetics and Weight Reduction of Clobenzorex Slow Release and Immediate Release Formulations in Obese Patients

Clobenzorex is an anorexigenic drug that is widely used in Mexicofor the treatment of obesity, since it helps to reduce body weight. This drug is available as immediate release capsules. To improve compliance to treatment, it was developed a new slow release formulation. In order to establish its usefulness, oral pharmacokinetics and weight reduction of slow release and immediate release formulations of clobenzorex in obese patients were compared. Sixty patients with a BMI higher than 27 kg/m2 were included in the study. Two groups of 30 patients were formed, one of them received 30 mg immediate release formulation b.i.d. and the other group received one 60 mg slow release formulation once a day, since under this scheme these formulations are prescribed. Blood samples were obtained at selected times during the first day and once weekly during 4 weeks. After the last dose, samples were obtained at selected times during 48 h. Plasma levels were determined by HPLC-MS/MS and pharmacokinetic parameters were obtained. Reduction in Cmax due to increased tmax, as well as, increased half-life were observed with the slow release formulation in comparison with immediate release formulation. Although lower plasma levels of clobenzorex were reached with the slow release formulation, reduction of body weight was similar with both products. Based on the results, it was concluded that slow release formulation of clobenzorex is an adequate formulation of clobenzorex, since pharmacokinetics and effects observed are compatible with a once a day administration.

Migration and Transformation of Coated Controlled Release Nitrogen in Soil under Co-situs Application Mode

By using field trials, the migration and transformation of coated controlled release nitrogen （YZS80） in soil under the co-situs application mode were studied. The results indicated that YZS80 nitrogen dissolved out in average speed of about 0.4%/d and 32% totally in 80 d compared with common compound fertUizer. For YZS80, in the vertical downward direction of application points, urea nitrogen content increased significantly （P 〈0.05） in the 45 -80 d and the 30 -60 cm soil layers; nitrate nitrogen content was little change range and in moderate （10 -100 mg/kg） in 0 -80 d and 10 -60 cm soil layers, but increased significantly （ P 〈0.05） 45 -80 d compared to 0 -45 d; ammonium nitrogen content was significant lower （P〈0.05） before 45 d in 10 -30 cm soil layers, but significant higher（P〈0.05） after 45 d in 10 -60 cm soil layers; NO3^- -N/NH4^＋ -N meets gradually the needs of the crop with the extension of time. Under the co-situs application mode, the possibility of burning root and salt injury and loss dsk of nitrate leaching is a significant reduction.

Effect of Starch Sources on the Release Rates of Herbicides Encapsulated

The effects of starch sources on the behaviors of starch matrices and on the rates of herbicides released from the matrices were studied for slow release. The starches considered include native corn starch, wheat starch, potato starch and cassava starch. The matrices were prepared through encapsulating 2,4-dichlorophenoxyacetic or 2,4,5 trichlorophenoxyacetic acids as model herbicides with hot-gelatinized starch pastes. The encapsulation was evaluated in terms of herbicide content, swellability, encapsulation efficiency, and release rate. The results show that starch sources play an important role on the matrix behaviors and on release rates. The rate of 2,4-D released follows the order： wheat starch 〈 potaot starch 〈 corn starch 〈 cassava starch. And for the rate of 2,4,5-T, this order is nearly the same only with an exception that the late two kinds of starch are similar. It is also demonstrated that herbicides with different water solubility show different release rates, no matter what type of starch is used as the matrices.

Pyraclostrobin-loaded poly(lactic-co-glycolic acid) nanospheres: Preparation and characteristics

We used poly(lactic-co-glycolic acid)(PLGA) as a carrier polymer for pyraclostrobin-loaded nanospheres. Using the ultrasound emulsification-solvent evaporation method, the physicochemical characteristics and release properties of the pyraclostrobin-loaded nanospheres were studied by dialysis. The optimal nanospheres prepared had a diameter of 0.6 μm, an active ingredient loading of 17.2%, and a loading rate of 89.7%. Infrared spectroscopy data and differential scanning calorimetry revealed that pyraclostrobin was successfully embedded in the carrier PLGA, and photostability tests indicated enhanced ultraviolet resistance of pyraclostrobin-loaded PLGA nanospheres nanospheres. Release property testing indicated that smaller particles had a faster release rate. Nanospheres also had a faster release rate in slightly acidic and slightly basic environments than in a neutral condition. Agitated nanospheres had a faster release rate than immobile nanospheres. The cumulative release kinetics of pyraclostrobin-loaded nanospheres was consistent with the first order kinetic equation and the Weibull equation.