Effects of mixed fertilizers formed by the compounding of two targeted controlled-release nitrogen fertilizers on yield,nitrogen use efficiency,and ammonia volatilization in double-cropping rice

One-time application of mixed fertilizer formed by the compounding of two controlled-release nitrogen fertilizers(CRUs)with targeted N supply during the periods from transplantation(TS)to panicle initiation(PI)and from PI to heading(HS)is expected to synchronize the double-peak N demand of rice.However,its effects on the yield and N use efficiency(NUE)of labor-intensive double-cropping rice were unknown.Two targeted CRU(CRU_(A)and CRU_(B))were compounded in five ratios(CRU_(A):CRU_(B)=10:0,7:3,5:5,3:7,and 0:10)to form five mixed fertilizers(BBFs):BBF1-5.A field experiment was performed to investigate the characteristics of N supply in early and late seasons under different BBFs and their effects on N uptake,yield,and ammonia volatilization(AV)loss from paddy fields of double-cropping rice.Conventional high-yield fertilization(CK,three split applications of urea)and zero-N treatments were established as controls.The N supply dropped significantly with the increased compound ratio of CRU_(B)during the period from TS to PI,but increased during the period from PI to HS.With the exception of the period from TS to PI in the late rice season,the N uptake of early and late rice maintained close synchronicity with the N supply of BBFs during the double-peak periods.Excessive N supply(BBF1 and BBF2)in the late rice season during the period from TS to PI increased N loss by AV.The effect of BBF on grain yield increase varied widely between seasons,irrespective of year.Among the BBFs,the BBF2 treatment of early rice not only stabilized the spikelets per panicle but also ensured a high number of effective panicles by promoting N uptake during the period from TS to PI and a high grain-filling percentage by appropriately reducing the N supply at the later PI stage,resulting in the highest rice yield.While stabilizing the effective panicle number,the BBF4 treatment of late rice increased the number of spikelets per panicle by promoting N uptake during the period from PI to HS,resulting in the highest rice yield.The two-year average yield and apparent N recovery efficiency of the BBF2 treatment during the early rice season were 9.6 t ha 1 and 45.3%,while those of late rice in BBF4 were 9.6 t ha 1 and 43.0%,respectively.The yield and NUE indexes of BBF2 in early rice and BBF4 in late rice showed no significant difference from those of CK.The AVs of BBF2 during the early rice season and of BBF4 during the late rice season were 50.0%and 76.8%lower,respectively,than those of CK.BBF2 and BBF4 could effectively replace conventional urea split fertilization in early and late rice seasons,ensuring rice yield and NUE and reducing AV loss in paddy fields.

Studies on the Mechanism of Single Basal Application of Controlled-Release Fertilizers for Increasing Yield of Rice (Oryza sativa L.)

This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice （Oryza sativa L.）. Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance （CRF1） and polymer materials （CRF3） increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer （RSF1）. Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.

Controlled-release fertilizer(CRF): A green fertilizer for controlling non-point contamination in agriculture

Fertilizers contribute greatly to high yields but also result in environmental non-point contamination, including the emission of greenhouse gas(N 2O) and eutrophication of water bodies. How to solve this problem has become a serious challenge, especially for China as its high ecological pressure. Controlled-release fertilizer(CRF) has been developed to minimize the contamination while keeping high yield and has become a green fertilizer for agriculture. Several CRFs made with special coating technology were used for testing the fertilizer effects in yield and environment through pot experiment and field trial. The result indicated that the CRFs had higher N use efficiency, thus reducing N loss through leaching and volatilization while keeping higher yields. Comparing with imported standard CRFs, the test on CRFs showed similar fertilizer effect but with much lower cost. CRFs application is becoming a new approach for minimizing non-point contamination in agriculture.

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.

Effects of different types of slow-and controlled-release fertilizers on rice yield

This experiment explored the effects of single application of seven types of slow-and controlled-release fertilizers on rice yield and various population characteristics.Based on a study of the nitrogen(N)release characteristics of these fertilizers,pot experiments were conducted in 2018 and 2019 with split fertilization(CK,urea applied split equally at basal and panicle initiation stages,respectively)as control,which assessed the effects on SPAD value,yield and yield components,dynamic changes of rice tillers and dry matter accumulation.The results showed that the N release characteristics of different types of slow-and controlled-release fertilizers were significantly different.Polymer-coated urea(PCU)showed a controlledrelease mode and provided sustained release throughout the whole growth stages.Sulfur-coated urea(SCU)exhibited a slow-release mode,providing insufficient release at the middle and late stages.Urease inhibitor urea(AHA)and ureaformaldehyde(UF)yielded a rapid-release mode,with an explosive N release at the early stage and no release at the middle and late stages.These results showed that PCU delayed the peak seedling stage.Compared with CK,dry matter accumulation and SPAD showed no significant differences,and due to the continuous release of N throughout the growth stages,rice yield,spikelets per panicle,seed setting rate,and 1000-grain weight were all increased.Owing to the lack of N supply at the late stage and the low number of spikelets,SCU led to a reduction of rice yield,which is nevertheless not statistically significant.AHA and UF were susceptible to environmental factors and had varying effects on rice yield.The results of this experiment indicated that given a fixed amount of N applied in a pot,the stronger the N supply capacity and the longer the effective duration time of the fertilizer,the higher the dry matter accumulation at the late growth stage,and the higher the rice yield.

Physiological Basis of Photosynthetic Function and Senescence of Rice Leaves as Regulated by Controlled-Release Nitrogen Fertilizer

The physiological mechanism of photosynthetic function and senescence of rice leaves was studied by using early rice variety Baliangyou 100 and late rice variety Weiyou 46, treated with controlled-release nitrogen fertilizer （CRNF）, urea and no nitrogen fertilizer. CRNF showed obvious effects on delaying the senescence and prolonging photosynthetic function duration of rice leaves. Compared with urea, CRNF could significantly increase the chlorophyll content of functional leaves in both early and late rice varieties, and this difference between the treatments became larger as rice growth progressed; CRNF increased the activities of active oxygen scavenging enzymes super oxide dismutase （SOD） and peroxidase （POD）, and decreased the accumulation amount of malondialdehyde （MDA） in functional leaves during leaf aging; Photosynthetic rate of functional leaves in CRNF treatment was significantly higher than that in urea treatment. The result also indicated that CRNF could effectively regulate the contents of indole-3-acetic acid （IAA） and abscisic acid （ABA） in functional leaves; IAA content was higher and ABA content was lower in CRNF treatment than those in urea treatment. Therefore, application of CRNF could increase the rice yield significantly due to these physiological changes in the functional leaves.

Preparation and characterization of controlled-release fertilizers coated with marine polysaccharide derivatives

Encapsulation of water-soluble nitrogen fertilizers by membranes can be used to control the release of nutrients to maximize the fertilization ef fect and reduce environmental pollution.In this research,we formulated a new double-coated controlled-release fertilizer(CRF)by using food-grade microcrystalline wax(MW)and marine polysaccharide derivatives(calcium alginate and chitosan-glutaraldehyde copolymer).The pellets of water-soluble nitrogen fertilizer were coated with the marine polysaccharide derivatives and MW.A convenient and eco-friendly method was used to prepare the CRF.Scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR)were used to characterize the morphology and composition of the products.The nitrogen-release properties were determined in water using UV-Vis spectrophotometry.The controlled-release properties of the fertilizer were improved dramatically after coating with MW and the marine polysaccharide derivatives.The results show that the double-coated CRFs can release nitrogen in a controlled manner,have excellent controlled-release features,and meet the European Standard for CRFs.

Effects of Controlled-Release Fertilizers and Their Application Methods on Germination and Seedling Growth of Dent and Sweet Corns

Effects of controlled-release fertilizers (CRFs) (C-AS, polyolefin coated ammonium sulfate, 50-day-type; Dd-LP, polyolefincoated urea with dicyandiamide, 40-day-type; C-ANP, polyolefin coated ammonium nitrate phosphate, 40-day-type; andC-DAP, polyolefin coated diammonium acid phosphate, 40-day-type), ammonium sulphate and no fertilizer control, andtheir application methods (spot, band, surface and mixed) on germination and seedling development of sweet corn (Zeamays L.var. saccharata Sturt.) and dent corn (Zea mays L.var. indentata Sturt.) were investigated in a greenhouse. Underco-situs application (band and spot) of CRFs, there were no obvious differences in the germination speed and rate for bothdent corn and sweet corn relative to control. Mortality rates of sweet corn seedlings under co-situs application were highin experiment 1, but were very low in experiment 2, because the environmental conditions were different in the twoexperiments. That is, under lower temperature and weaker sunlight, young seedlings easily die due to high soil nutrientconcentration and slow growth speed of corn. Shoot weight of both dent and sweet corn did not greatly decrease inexperiment 1. In experiment 2, there were no significant differences in shoot and root weight of both corns between co-situs and surface or mixed application methods. However, with spot and band application of ammonium sulfate, shoot androot weight were significantly reduced. Soil EC and pH were considerably affected by co-situs application, especially atthe fertilizer application site. For both dent and sweet corn, EC in the 0-3 cm soil was significantly higher under co-situsapplication and surface application than that under mixed application, whereas in the 3-6 cm soil depth the situation wasreversed. Compared with control, mixed application of CRFs decreased soil pH slightly (0-3 cm depth) or greatly (3-6 cmdepth).

Subsurface banding of blended controlled-release urea can optimize rice yields while minimizing yield-scaled greenhouse gas emissions

Controlled-release urea(CRU)is widely reported to supply crop nitrogen(N)demand with one basal application,thus effectively replacing split applications of urea without diminishing grain yield and N use efficiency(NUE).However,its use for replacement for high-yield split applications of urea(CK)for rice is untested.In addition,the degree to which greenhouse gas(GHG)emissions in rice systems are affected when CRU is substituted for CK remains unclear.During 2017 and 2018,we sampled plant growth and gas emissions in a rice paddy field treated with three CRU types(sulfur-coated urea[SCU],polymer-coated urea[PCU],and bulk blended CRU[BBU])applied via two methods(surface broadcasting on the soil and subsurface banding at 5 cm depth),with CK as a control.The three CRUs led to different soil NH_(4)^(+)-N dynamics,and the N supply pattern under BBU was more beneficial for rice seedling establishment than under SCU and PCU,resulting in grain yield and NUE comparable to those under CK.CRU type showed no significant effect on either CH_(4) emissions or N_(2)O emissions,and broadcast CRUs exhibited significantly higher total GHG emissions than CK.However,banded CRUs significantly reduced the total GHG emissions in comparison with broadcast CRUs,by 9.2%averaged across the two years.Reduced CH_(4) emissions,particularly during the period prior to the middle drainage,contributed largely to the GHG difference.With comparably high grain yield and low total GHG emissions,banded BBU showed a low yield-scaled GHG(GHG emissions divided by grain yield)comparable to that under CK in both years.Overall,our study suggested that N management synchronized with rice demand and contributing to a high NUE tended to minimize yield-scaled GHG.Broadcast CRU can hardly substitute for CK in terms of either grain yield or GHG emissions,but banded BBU is a promising N management strategy for sustaining rice production while minimizing environmental impacts.

Advances in controlled-release fertilizer encapsulated by organic-inorganic composite membranes

Heavy use of conventional fertilizers can lead to negative environmental concerns.Controlled-release fertilizers(CRFs)can effectively reduce the amounts of fertilizers used,improve the availability of fer-tilizers,and which is conducive to the protection of the ecological environment and sustainable devel-opment of agriculture.Therefore,it is imperative to develop and use CRFs as an alternative to traditional fertilizers.This review aims to present the classification,raw material composition,benefits,release process,release mode,and manufacturing methods of fertilizers coated with organic-inorganic com-posite membranes(OICMs)in order to provide an overall update and summarize CRFs encapsulated by OICMs and provide an insight for future trends in the field of fertilizers.It is expected that utilizing CRFs encapsulated by OICMs and their characteristics for agricultural applications can provide innovative ideas and suggestions for developing novel CRFs suitable for modern and sustainable agriculture.

Biochar-compost-based controlled-release nitrogen fertilizer intended for an active microbial community

Nitrogen(N) fertilizers in agriculture suffer losses by volatilization of N to the air, surface runoff and leaching into the soil, resulting in low N use efficiency(NUE)( 50%) and raising severe environmental pollutions. Controlledrelease nitrogen fertilizers(CRNFs) can control the release of N nutrients to NUE in crop production. Different methods were used to develop new CRNFs.However, different CRNF technologies are still underdeveloped due to inadequate controlling on N releasing time and/or unsustainable diffusion. The study on the influences of CRNF processing parameters on microbial conditions are lacking when the CRNFs composed of various bio-ingredients such as biochar, composts, and biowaste. The complexity of processing methods, material biodegradability, and other physical properties make current CRNFs of questionable value in agricultural production. This research aims to develop a novel biochar-compost-based controlled-release urea fertilizer(BCRUF) to preserve microbial properties carried by the compost. The BCRUF was synthesized by pelletizing the 50:50(dry, wt/wt) mixture of biochar and compost. BCRUF was loaded with urea and then spray-coated with polylactic acid(PLA). The releasing time of two types of BCRUFs, coated and uncoated with PLA, for 80% of N release in water was up to 6 h at three different temperatures(4, 23, and 40 °C), compared to conventional urea fertilizer and commercial environmentally smart N(ESN) fertilizer. The releasing time of coated BCRUF for 80% N release in soil was up to 192 h(8 days). Fourier-transform infrared spectroscopy(FTIR) analysis revealed that no new functional groups were found in the release solution, indicating no new chemical hazards generated. The differential scanning calorimetry(DSC)tests also verified that its thermal stability could be up to 160 °C. The microbe populations in the BCRUF pellets were reduced after the pelleting and drying processes in BCRUF fabrication, but a few bacteria can endure in the air-drying process. BCRUF pellets soaked in water for 4 days retained some bacteria. The BCRUF showed very promising characteristics to improve NUE and sustainability in agricultural production.

味精废液有机无机BB肥的水稻肥效试验

在广东省两个试点进行田间小区试验,水稻施用味精废液有机无机BB肥1000 kg.hm-2,与习惯施肥相比增产320 kg.hm-2,达显著标准;产投比值为2.08,收益明显;土壤有机质、N、P2O5、K2O含量与种植前有不同程度的增加。施味精废液有机无机BB肥,不但能满足水稻对氮、磷、钾大量元素的需求,同时具有改土、培肥地力的作用。该肥作基肥一次施用,能有效节约劳动力投入。

控释BB肥对西瓜施用效果研究

[目的]研究控释BB肥对西瓜的施用效果,为控释肥的推广使用提供理论依据。[方法]以丰乐1号西瓜为试材,采用田间小区试验法研究了控释BB肥对西瓜产量、品质和氮素利用率的影响。[结果]控释BB肥能显著提高西瓜产量,在等养分施用下较常规施肥增产20.18%,在养分减少20%的情况下,仍能增产8.69%;控释BB肥能明显提高西瓜的品质,在等量、减量20%、减氮30%的3个不同控释BB肥处理中,西瓜果实的Vc和可溶性糖含量较常规施肥分别增加了28.69%和16.35%,硝酸盐含量也有显著的降低,氮素利用率分别较常规施肥提高38.13%、37.08%和27.79%。[结论]控释BB肥具有延缓养分释放的功能,是一种既增产又经济,还对环境友好的肥料。

BB肥对水稻生育及产量的影响

ＢＢ（ＢｕｃｋＢｌｅｎｄ）肥是按不同作物所需养分配制成的专用肥料，具有浓度高，加工简单，成本较低，运输方便，施用简便等优点。本试验选用质量分数ω＝５０％水稻型ＢＢ肥与质量分数ω＝３５％的全元肥（复合肥）和常规施用的单质化肥（碳铵，钙镁磷，氯化钾，尿素）以相等价格投入作对比试验，ＢＢ肥在水稻生育和产量上明显优于其他两种用肥。

控释BB肥对西瓜生长期土壤酶活性的影响

研究控释BB肥(掺混肥)对土壤中酶活性的影响,为控释肥的推广使用提供理论依据。采用田间小区试验法研究了控释BB肥对西瓜不同生育期土壤脲酶、中性磷酸酶和蔗糖酶活性的影响。在试验条件下,由于控释BB肥对养分的显著控释效果,它的施用对土壤中这三种酶活性的影响要好于习惯施肥处理。

隆阳区杂交油菜BB控释肥肥效效应分析

为了进一步分析杂交油菜在不同施肥水平下的丰产性，筛选出最理想施肥基数，为高产攻关创造有利条件，为大面积油菜生产获取高产提供科学依据。通过2011_2012年在云南保山市隆阳区金鸡乡进行杂交油菜BB控释肥栽培试验，对其参试的‘云油杂10号’进行5个处理的肥效效应研究。结果表明：同一品种在相同的管理条件下，5个不同施肥水平处理小区实收产量在606．66-3222．5kg／hm2之间，其中，以全生育期施肥总量尿素675kg／hm2，普钙750kg／hm2，硫酸钾300kg／hm2，,硼肥22．5kg／hm2（底肥：提苗肥：壮苗肥：蕾苔肥=18．5：30：34．3：17．2）的处理产量最高，可作为类似云南隆阳区生态气候油菜高产区大面积推广应用。BB控释肥释放时期提早释放20-25天，增加控释肥用量150kg／hm2，就能达到预期的节本增效效果。

树脂包膜尿素与普通尿素配施及树脂包膜BB肥在玉米上增产效果研究

在驻马店市农科所进行了树脂包膜尿素与普通尿素配施试验。试验结果表明,树脂包膜尿素与普通尿素配施处理的产量以控释尿素70%+普通尿素30%处理最好,为7 665 kg/hm2,比100%金正大树脂包膜尿素增产465 kg/hm2,提高了6.5%,比普通复合肥处理增产1 125 kg/hm2,提高了19.0%,比对照增产了2 400 kg/hm2,提高45.6%。金正大控释专用BB肥处理比普通复合肥处理增产90 kg/hm2,提高1.5%。

木薯应用控释BB肥研究

研究了控释BB肥在木薯上的应用效果。结果表明,随着控释BB肥用量的增加,木薯株高、茎基部粗度显著增加,施氮量20kg处理的木薯产量分别较施氮量10、15kg处理增加33.8%和32.7%。随着施肥次数的增加,木薯株高、茎基部粗度有增加趋势,在低施肥量下随着施肥次数的增加,结薯数和产量也有增加趋势,但高施肥量下以一次施肥或二次施肥产量较高,三次施肥明显降低。因此,木薯应用控释BB肥时应适当增加肥料用量以获得显著增产效果,同时,施肥方法采用一次施肥或二次施肥均可。

控释BB肥对西瓜种植土壤养分的影响

[目的]探讨控释BB肥对西瓜栽培土壤养分的影响。[方法]以丰乐1号西瓜为试材,设置5个施肥处理（不施肥料CK,习惯施肥,等量、减量、减氮控释BB肥）,探讨了不同肥料施入土壤后的养分动态变化规律。[结果]习惯施肥处理的养分在短期内达最大值。在3个控释BB肥处理中,等量处理的土壤碱解氮最高 减N增P、K处理的土壤速效磷和速效钾均最高。相对于习惯施肥处理,这3个控释BB肥处理的速效NPK养分均有滞后释放的特性,基本上都在西瓜进入膨大期（施肥后45~60 d）时达到释放高峰,更能有效地提高土壤中速效养分的含量。[结论]控释BB肥的养分释放曲线与西瓜的养分需求曲线有一定的相似性,有利于获得高产优质的西瓜。

控失BB肥在小麦上的应用效果

为了验证控失BB肥的优越性并发现其在施用过程中存在的问题,为进一步改进控失尿素产品提出建议,对控失BB肥在小麦上的应用效果进行了大田试验和示范处理。试验结果表明,控失BB肥能有效提高氮肥利用率,但氮肥利用率随氮肥使用量的增加而下降。示范结果表明,控失BB肥比普通BB肥处理小麦增产372.0 kg/hm^2,增产率4.7%。